Down-integrate from internal code base.

101 files changed, 6756 insertions, 2209 deletions

diff --git a/src/google/protobuf/any.cc b/src/google/protobuf/any.cc
index 7351d377..f3ca06bf 100644
--- a/src/google/protobuf/any.cc
+++ b/src/google/protobuf/any.cc
@@ -65,9 +65,16 @@ bool AnyMetadata::UnpackTo(Message* message) const {
 }
 
 bool AnyMetadata::InternalIs(const Descriptor* descriptor) const {
-  return type_url_->GetNoArena(
-             &::google::protobuf::internal::GetEmptyString()) ==
-         GetTypeUrl(descriptor);
+  const string type_url = type_url_->GetNoArena(
+             &::google::protobuf::internal::GetEmptyString());
+  const string full_name = descriptor->full_name();
+  if (type_url.length() < full_name.length()) {
+      return false;
+  }
+  return (0 == type_url.compare(
+    type_url.length() - full_name.length(),
+    full_name.length(),
+    full_name));
 }
 
 bool ParseAnyTypeUrl(const string& type_url, string* full_type_name) {
diff --git a/src/google/protobuf/any.h b/src/google/protobuf/any.h
index f760ad5d..c8dbef13 100644
--- a/src/google/protobuf/any.h
+++ b/src/google/protobuf/any.h
@@ -75,7 +75,7 @@ extern const char kTypeGoogleProdComPrefix[];  // "type.googleprod.com/".
 // Get the proto type name from Any::type_url value. For example, passing
 // "type.googleapis.com/rpc.QueryOrigin" will return "rpc.QueryOrigin" in
 // *full_type_name. Returns false if type_url does not start with
-// "type.googleapis.com".
+// "type.googleapis.com" or "type.googleprod.com".
 bool ParseAnyTypeUrl(const string& type_url, string* full_type_name);
 
 // See if message is of type google.protobuf.Any, if so, return the descriptors
diff --git a/src/google/protobuf/any.pb.cc b/src/google/protobuf/any.pb.cc
index 321fd315..0bf523b3 100644
--- a/src/google/protobuf/any.pb.cc
+++ b/src/google/protobuf/any.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
diff --git a/src/google/protobuf/any.proto b/src/google/protobuf/any.proto
index 423699be..e8a18bc3 100644
--- a/src/google/protobuf/any.proto
+++ b/src/google/protobuf/any.proto
@@ -27,21 +27,22 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
 package google.protobuf;
 
-option java_generate_equals_and_hash = true;
-option java_multiple_files = true;
-option java_outer_classname = "AnyProto";
-option java_package = "com.google.protobuf";
 option csharp_namespace = "Google.Protobuf.WellKnownTypes";
+option java_package = "com.google.protobuf";
+option java_outer_classname = "AnyProto";
+option java_multiple_files = true;
+option java_generate_equals_and_hash = true;
 option objc_class_prefix = "GPB";
 
-
 // `Any` contains an arbitrary serialized message along with a URL
 // that describes the type of the serialized message.
 //
+//
 // JSON
 // ====
 // The JSON representation of an `Any` value uses the regular
@@ -62,8 +63,8 @@ option objc_class_prefix = "GPB";
 //
 // If the embedded message type is well-known and has a custom JSON
 // representation, that representation will be embedded adding a field
-// `value` which holds the custom JSON in addition to the the `@type`
-// field. Example (for message [google.protobuf.Duration][google.protobuf.Duration]):
+// `value` which holds the custom JSON in addition to the `@type`
+// field. Example (for message [google.protobuf.Duration][]):
 //
 //     {
 //       "@type": "type.googleapis.com/google.protobuf.Duration",
@@ -80,7 +81,7 @@ message Any {
   // * If no schema is provided, `https` is assumed.
   // * The last segment of the URL's path must represent the fully
   //   qualified name of the type (as in `path/google.protobuf.Duration`).
-  // * An HTTP GET on the URL must yield a [google.protobuf.Type][google.protobuf.Type]
+  // * An HTTP GET on the URL must yield a [google.protobuf.Type][]
   //   value in binary format, or produce an error.
   // * Applications are allowed to cache lookup results based on the
   //   URL, or have them precompiled into a binary to avoid any
diff --git a/src/google/protobuf/api.pb.cc b/src/google/protobuf/api.pb.cc
index ed90702c..e589a89d 100644
--- a/src/google/protobuf/api.pb.cc
+++ b/src/google/protobuf/api.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
diff --git a/src/google/protobuf/api.proto b/src/google/protobuf/api.proto
index 597a6497..dbe87b8f 100644
--- a/src/google/protobuf/api.proto
+++ b/src/google/protobuf/api.proto
@@ -27,6 +27,7 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
 package google.protobuf;
@@ -34,11 +35,11 @@ package google.protobuf;
 import "google/protobuf/source_context.proto";
 import "google/protobuf/type.proto";
 
+option csharp_namespace = "Google.Protobuf.WellKnownTypes";
 option java_package = "com.google.protobuf";
 option java_outer_classname = "ApiProto";
 option java_multiple_files = true;
 option java_generate_equals_and_hash = true;
-option csharp_namespace = "Google.Protobuf.WellKnownTypes";
 option objc_class_prefix = "GPB";
 
 // Api is a light-weight descriptor for a protocol buffer service.
@@ -75,6 +76,7 @@ message Api {
   // be omitted. Zero major versions must only be used for
   // experimental, none-GA apis.
   //
+  //
   string version = 4;
 
   // Source context for the protocol buffer service represented by this
@@ -141,7 +143,6 @@ message Method {
 //
 //     package google.storage.v2;
 //     service Storage {
-//       // (-- see AccessControl.GetAcl --)
 //       rpc GetAcl(GetAclRequest) returns (Acl);
 //
 //       // Get a data record.
diff --git a/src/google/protobuf/arena.h b/src/google/protobuf/arena.h
index 40c1e7c2..6a35183e 100644
--- a/src/google/protobuf/arena.h
+++ b/src/google/protobuf/arena.h
@@ -591,14 +591,12 @@ class LIBPROTOBUF_EXPORT Arena {
   // This is inside Arena because only Arena has the friend relationships
   // necessary to see the underlying generated code traits.
   template<typename T>
-  struct is_destructor_skippable :
-      public google::protobuf::internal::integral_constant<bool,
-              sizeof(InternalIsDestructorSkippableHelper::DestructorSkippable<
-                     const T>(static_cast<const T*>(0))) ==
-              sizeof(char) ||
-              google::protobuf::internal::has_trivial_destructor<T>::value> {
-  };
-
+  struct is_destructor_skippable
+      : public google::protobuf::internal::integral_constant<
+            bool,
+            sizeof(InternalIsDestructorSkippableHelper::DestructorSkippable<
+                   const T>(static_cast<const T*>(0))) == sizeof(char) ||
+                google::protobuf::internal::has_trivial_destructor<T>::value> {};
 
   // CreateMessage<T> requires that T supports arenas, but this private method
   // works whether or not T supports arenas. These are not exposed to user code
diff --git a/src/google/protobuf/arenastring.h b/src/google/protobuf/arenastring.h
index 1dacdc68..ef57033b 100755
--- a/src/google/protobuf/arenastring.h
+++ b/src/google/protobuf/arenastring.h
@@ -36,7 +36,6 @@
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/stubs/fastmem.h>
-
 #include <google/protobuf/arena.h>
 #include <google/protobuf/generated_message_util.h>
 
diff --git a/src/google/protobuf/compiler/command_line_interface.cc b/src/google/protobuf/compiler/command_line_interface.cc
index 26a4f0b0..deb3d0f1 100644
--- a/src/google/protobuf/compiler/command_line_interface.cc
+++ b/src/google/protobuf/compiler/command_line_interface.cc
@@ -271,15 +271,35 @@ class CommandLineInterface::ErrorPrinter : public MultiFileErrorCollector,
   // implements MultiFileErrorCollector ------------------------------
   void AddError(const string& filename, int line, int column,
                 const string& message) {
+    AddErrorOrWarning(filename, line, column, message, "error", std::cerr);
+  }
+
+  void AddWarning(const string& filename, int line, int column,
+                  const string& message) {
+    AddErrorOrWarning(filename, line, column, message, "warning", std::clog);
+  }
 
+  // implements io::ErrorCollector -----------------------------------
+  void AddError(int line, int column, const string& message) {
+    AddError("input", line, column, message);
+  }
+
+  void AddWarning(int line, int column, const string& message) {
+    AddErrorOrWarning("input", line, column, message, "warning", std::clog);
+  }
+
+ private:
+  void AddErrorOrWarning(
+      const string& filename, int line, int column,
+      const string& message, const string& type, ostream& out) {
     // Print full path when running under MSVS
     string dfile;
     if (format_ == CommandLineInterface::ERROR_FORMAT_MSVS &&
         tree_ != NULL &&
         tree_->VirtualFileToDiskFile(filename, &dfile)) {
-      std::cerr << dfile;
+      out << dfile;
     } else {
-      std::cerr << filename;
+      out << filename;
     }
 
     // Users typically expect 1-based line/column numbers, so we add 1
@@ -288,24 +308,22 @@ class CommandLineInterface::ErrorPrinter : public MultiFileErrorCollector,
       // Allow for both GCC- and Visual-Studio-compatible output.
       switch (format_) {
         case CommandLineInterface::ERROR_FORMAT_GCC:
-          std::cerr << ":" << (line + 1) << ":" << (column + 1);
+          out << ":" << (line + 1) << ":" << (column + 1);
           break;
         case CommandLineInterface::ERROR_FORMAT_MSVS:
-          std::cerr << "(" << (line + 1)
-                    << ") : error in column=" << (column + 1);
+          out << "(" << (line + 1) << ") : "
+              << type << " in column=" << (column + 1);
           break;
       }
     }
 
-    std::cerr << ": " << message << std::endl;
-  }
-
-  // implements io::ErrorCollector -----------------------------------
-  void AddError(int line, int column, const string& message) {
-    AddError("input", line, column, message);
+    if (type == "warning") {
+      out << ": warning: " << message << std::endl;
+    } else {
+      out << ": " << message << std::endl;
+    }
   }
 
- private:
   const ErrorFormat format_;
   DiskSourceTree *tree_;
 };
@@ -1353,7 +1371,7 @@ void CommandLineInterface::PrintHelpText() {
 "                              defined in the given proto files. Groups share\n"
 "                              the same field number space with the parent \n"
 "                              message. Extension ranges are counted as \n"
-"                              occupied fields numbers."
+"                              occupied fields numbers.\n"
       << std::endl;
   if (!plugin_prefix_.empty()) {
     std::cerr <<
@@ -1443,6 +1461,7 @@ bool CommandLineInterface::GenerateDependencyManifestFile(
   for (int i = 0; i < parsed_files.size(); i++) {
     GetTransitiveDependencies(parsed_files[i],
                               false,
+                              false,
                               &already_seen,
                               file_set.mutable_file());
   }
@@ -1522,6 +1541,7 @@ bool CommandLineInterface::GeneratePluginOutput(
   for (int i = 0; i < parsed_files.size(); i++) {
     request.add_file_to_generate(parsed_files[i]->name());
     GetTransitiveDependencies(parsed_files[i],
+                              true,  // Include json_name for plugins.
                               true,  // Include source code info.
                               &already_seen, request.mutable_proto_file());
   }
@@ -1654,6 +1674,7 @@ bool CommandLineInterface::WriteDescriptorSet(
     set<const FileDescriptor*> already_seen;
     for (int i = 0; i < parsed_files.size(); i++) {
       GetTransitiveDependencies(parsed_files[i],
+                                true,  // Include json_name
                                 source_info_in_descriptor_set_,
                                 &already_seen, file_set.mutable_file());
     }
@@ -1665,6 +1686,7 @@ bool CommandLineInterface::WriteDescriptorSet(
       }
       FileDescriptorProto* file_proto = file_set.add_file();
       parsed_files[i]->CopyTo(file_proto);
+      parsed_files[i]->CopyJsonNameTo(file_proto);
       if (source_info_in_descriptor_set_) {
         parsed_files[i]->CopySourceCodeInfoTo(file_proto);
       }
@@ -1699,7 +1721,9 @@ bool CommandLineInterface::WriteDescriptorSet(
 }
 
 void CommandLineInterface::GetTransitiveDependencies(
-    const FileDescriptor* file, bool include_source_code_info,
+    const FileDescriptor* file,
+    bool include_json_name,
+    bool include_source_code_info,
     set<const FileDescriptor*>* already_seen,
     RepeatedPtrField<FileDescriptorProto>* output) {
   if (!already_seen->insert(file).second) {
@@ -1709,13 +1733,18 @@ void CommandLineInterface::GetTransitiveDependencies(
 
   // Add all dependencies.
   for (int i = 0; i < file->dependency_count(); i++) {
-    GetTransitiveDependencies(file->dependency(i), include_source_code_info,
+    GetTransitiveDependencies(file->dependency(i),
+                              include_json_name,
+                              include_source_code_info,
                               already_seen, output);
   }
 
   // Add this file.
   FileDescriptorProto* new_descriptor = output->Add();
   file->CopyTo(new_descriptor);
+  if (include_json_name) {
+    file->CopyJsonNameTo(new_descriptor);
+  }
   if (include_source_code_info) {
     file->CopySourceCodeInfoTo(new_descriptor);
   }
diff --git a/src/google/protobuf/compiler/command_line_interface.h b/src/google/protobuf/compiler/command_line_interface.h
index 7e611c44..f196ffc5 100644
--- a/src/google/protobuf/compiler/command_line_interface.h
+++ b/src/google/protobuf/compiler/command_line_interface.h
@@ -262,8 +262,11 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   // in order.  Any files in *already_seen will not be added, and each file
   // added will be inserted into *already_seen.  If include_source_code_info is
   // true then include the source code information in the FileDescriptorProtos.
+  // If include_json_name is true, populate the json_name field of
+  // FieldDescriptorProto for all fields.
   static void GetTransitiveDependencies(
       const FileDescriptor* file,
+      bool include_json_name,
       bool include_source_code_info,
       set<const FileDescriptor*>* already_seen,
       RepeatedPtrField<FileDescriptorProto>* output);
diff --git a/src/google/protobuf/compiler/command_line_interface_unittest.cc b/src/google/protobuf/compiler/command_line_interface_unittest.cc
index fa792dae..4ce81a75 100644
--- a/src/google/protobuf/compiler/command_line_interface_unittest.cc
+++ b/src/google/protobuf/compiler/command_line_interface_unittest.cc
@@ -886,6 +886,10 @@ TEST_F(CommandLineInterfaceTest, WriteDescriptorSet) {
   EXPECT_EQ("bar.proto", descriptor_set.file(0).name());
   // Descriptor set should not have source code info.
   EXPECT_FALSE(descriptor_set.file(0).has_source_code_info());
+  // Descriptor set should have json_name.
+  EXPECT_EQ("Bar", descriptor_set.file(0).message_type(0).name());
+  EXPECT_EQ("foo", descriptor_set.file(0).message_type(0).field(0).name());
+  EXPECT_TRUE(descriptor_set.file(0).message_type(0).field(0).has_json_name());
 }
 
 TEST_F(CommandLineInterfaceTest, WriteDescriptorSetWithDuplicates) {
@@ -919,6 +923,10 @@ TEST_F(CommandLineInterfaceTest, WriteDescriptorSetWithDuplicates) {
   EXPECT_EQ("baz.proto", descriptor_set.file(2).name());
   // Descriptor set should not have source code info.
   EXPECT_FALSE(descriptor_set.file(0).has_source_code_info());
+  // Descriptor set should have json_name.
+  EXPECT_EQ("Bar", descriptor_set.file(0).message_type(0).name());
+  EXPECT_EQ("foo", descriptor_set.file(0).message_type(0).field(0).name());
+  EXPECT_TRUE(descriptor_set.file(0).message_type(0).field(0).has_json_name());
 }
 
 TEST_F(CommandLineInterfaceTest, WriteDescriptorSetWithSourceInfo) {
@@ -1413,6 +1421,18 @@ TEST_F(CommandLineInterfaceTest, PluginReceivesSourceCodeInfo) {
       "Saw message type MockCodeGenerator_HasSourceCodeInfo: 1.");
 }
 
+TEST_F(CommandLineInterfaceTest, PluginReceivesJsonName) {
+  CreateTempFile("foo.proto",
+    "syntax = \"proto2\";\n"
+    "message MockCodeGenerator_HasJsonName {\n"
+    "  optional int32 value = 1;\n"
+    "}\n");
+
+  Run("protocol_compiler --plug_out=$tmpdir --proto_path=$tmpdir foo.proto");
+
+  ExpectErrorSubstring("Saw json_name: 1");
+}
+
 TEST_F(CommandLineInterfaceTest, GeneratorPluginNotFound) {
   // Test what happens if the plugin isn't found.
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_file.cc b/src/google/protobuf/compiler/cpp/cpp_file.cc
index 9aa41534..37e4bae4 100644
--- a/src/google/protobuf/compiler/cpp/cpp_file.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_file.cc
@@ -252,6 +252,7 @@ void FileGenerator::GenerateSource(io::Printer* printer) {
     "#include <algorithm>\n"    // for swap()
     "\n"
     "#include <google/protobuf/stubs/common.h>\n"
+    "#include <google/protobuf/stubs/port.h>\n"
     "#include <google/protobuf/stubs/once.h>\n"
     "#include <google/protobuf/io/coded_stream.h>\n"
     "#include <google/protobuf/wire_format_lite_inl.h>\n",
diff --git a/src/google/protobuf/compiler/importer.cc b/src/google/protobuf/compiler/importer.cc
index 8333684e..0d9093c0 100644
--- a/src/google/protobuf/compiler/importer.cc
+++ b/src/google/protobuf/compiler/importer.cc
@@ -185,6 +185,19 @@ void SourceTreeDescriptorDatabase::ValidationErrorCollector::AddError(
   owner_->error_collector_->AddError(filename, line, column, message);
 }
 
+void SourceTreeDescriptorDatabase::ValidationErrorCollector::AddWarning(
+    const string& filename,
+    const string& element_name,
+    const Message* descriptor,
+    ErrorLocation location,
+    const string& message) {
+  if (owner_->error_collector_ == NULL) return;
+
+  int line, column;
+  owner_->source_locations_.Find(descriptor, location, &line, &column);
+  owner_->error_collector_->AddWarning(filename, line, column, message);
+}
+
 // ===================================================================
 
 Importer::Importer(SourceTree* source_tree,
diff --git a/src/google/protobuf/compiler/importer.h b/src/google/protobuf/compiler/importer.h
index f010fd08..cc8fcc39 100644
--- a/src/google/protobuf/compiler/importer.h
+++ b/src/google/protobuf/compiler/importer.h
@@ -121,6 +121,12 @@ class LIBPROTOBUF_EXPORT SourceTreeDescriptorDatabase : public DescriptorDatabas
                   ErrorLocation location,
                   const string& message);
 
+    virtual void AddWarning(const string& filename,
+                            const string& element_name,
+                            const Message* descriptor,
+                            ErrorLocation location,
+                            const string& message);
+
    private:
     SourceTreeDescriptorDatabase* owner_;
   };
@@ -188,6 +194,9 @@ class LIBPROTOBUF_EXPORT MultiFileErrorCollector {
   virtual void AddError(const string& filename, int line, int column,
                         const string& message) = 0;
 
+  virtual void AddWarning(const string& filename, int line, int column,
+                          const string& message) {}
+
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MultiFileErrorCollector);
 };
diff --git a/src/google/protobuf/compiler/importer_unittest.cc b/src/google/protobuf/compiler/importer_unittest.cc
index 33c9328f..be19aa2e 100644
--- a/src/google/protobuf/compiler/importer_unittest.cc
+++ b/src/google/protobuf/compiler/importer_unittest.cc
@@ -71,6 +71,7 @@ class MockErrorCollector : public MultiFileErrorCollector {
   ~MockErrorCollector() {}
 
   string text_;
+  string warning_text_;
 
   // implements ErrorCollector ---------------------------------------
   void AddError(const string& filename, int line, int column,
@@ -78,6 +79,12 @@ class MockErrorCollector : public MultiFileErrorCollector {
     strings::SubstituteAndAppend(&text_, "$0:$1:$2: $3\n",
                                  filename, line, column, message);
   }
+
+  void AddWarning(const string& filename, int line, int column,
+                  const string& message) {
+    strings::SubstituteAndAppend(&warning_text_, "$0:$1:$2: $3\n",
+                                 filename, line, column, message);
+  }
 };
 
 // -------------------------------------------------------------------
@@ -123,6 +130,7 @@ class ImporterTest : public testing::Test {
 
   // Return the collected error text
   string error() const { return error_collector_.text_; }
+  string warning() const { return error_collector_.warning_text_; }
 
   MockErrorCollector error_collector_;
   MockSourceTree source_tree_;
diff --git a/src/google/protobuf/compiler/java/java_enum.cc b/src/google/protobuf/compiler/java/java_enum.cc
index 8a09f3a8..5fc9b002 100644
--- a/src/google/protobuf/compiler/java/java_enum.cc
+++ b/src/google/protobuf/compiler/java/java_enum.cc
@@ -85,17 +85,10 @@ EnumGenerator::~EnumGenerator() {}
 
 void EnumGenerator::Generate(io::Printer* printer) {
   WriteEnumDocComment(printer, descriptor_);
-  if (HasDescriptorMethods(descriptor_)) {
-    printer->Print(
-      "public enum $classname$\n"
-      "    implements com.google.protobuf.ProtocolMessageEnum {\n",
-      "classname", descriptor_->name());
-  } else {
-    printer->Print(
-      "public enum $classname$\n"
-      "    implements com.google.protobuf.Internal.EnumLite {\n",
-      "classname", descriptor_->name());
-  }
+  printer->Print(
+    "public enum $classname$\n"
+    "    implements com.google.protobuf.ProtocolMessageEnum {\n",
+    "classname", descriptor_->name());
   printer->Indent();
 
   for (int i = 0; i < canonical_values_.size(); i++) {
@@ -311,7 +304,6 @@ void EnumGenerator::Generate(io::Printer* printer) {
       "}\n"
       "\n");
 
-    // index is only used for reflection; lite implementation does not need it
     printer->Print("private final int index;\n");
   }
 
diff --git a/src/google/protobuf/compiler/java/java_enum_field_lite.cc b/src/google/protobuf/compiler/java/java_enum_field_lite.cc
index e8bf15d0..e3e87c58 100644
--- a/src/google/protobuf/compiler/java/java_enum_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_enum_field_lite.cc
@@ -596,9 +596,7 @@ GenerateInterfaceMembers(io::Printer* printer) const {
 void RepeatedImmutableEnumFieldLiteGenerator::
 GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
-    // TODO(dweis): Switch to IntList?
-    "private com.google.protobuf.Internal.ProtobufList<\n"
-    "    java.lang.Integer> $name$_;\n"
+    "private com.google.protobuf.Internal.IntList $name$_;\n"
     "private static final com.google.protobuf.Internal.ListAdapter.Converter<\n"
     "    java.lang.Integer, $type$> $name$_converter_ =\n"
     "        new com.google.protobuf.Internal.ListAdapter.Converter<\n"
@@ -623,7 +621,7 @@ GenerateMembers(io::Printer* printer) const {
   WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$(int index) {\n"
-    "  return $name$_converter_.convert($name$_.get(index));\n"
+    "  return $name$_converter_.convert($name$_.getInt(index));\n"
     "}\n");
   if (SupportUnknownEnumValue(descriptor_->file())) {
     WriteFieldDocComment(printer, descriptor_);
@@ -635,7 +633,7 @@ GenerateMembers(io::Printer* printer) const {
     WriteFieldDocComment(printer, descriptor_);
     printer->Print(variables_,
       "$deprecation$public int get$capitalized_name$Value(int index) {\n"
-      "  return $name$_.get(index);\n"
+      "  return $name$_.getInt(index);\n"
       "}\n");
   }
 
@@ -649,7 +647,7 @@ GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
     "private void ensure$capitalized_name$IsMutable() {\n"
     "  if (!$is_mutable$) {\n"
-    "    $name$_ = newProtobufList($name$_);\n"
+    "    $name$_ = newIntList($name$_);\n"
     "  }\n"
     "}\n");
   WriteFieldDocComment(printer, descriptor_);
@@ -660,7 +658,7 @@ GenerateMembers(io::Printer* printer) const {
     "    throw new NullPointerException();\n"
     "  }\n"
     "  ensure$capitalized_name$IsMutable();\n"
-    "  $name$_.set(index, value.getNumber());\n"
+    "  $name$_.setInt(index, value.getNumber());\n"
     "}\n");
   WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
@@ -669,7 +667,7 @@ GenerateMembers(io::Printer* printer) const {
     "    throw new NullPointerException();\n"
     "  }\n"
     "  ensure$capitalized_name$IsMutable();\n"
-    "  $name$_.add(value.getNumber());\n"
+    "  $name$_.addInt(value.getNumber());\n"
     "}\n");
   WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
@@ -677,13 +675,13 @@ GenerateMembers(io::Printer* printer) const {
     "    java.lang.Iterable<? extends $type$> values) {\n"
     "  ensure$capitalized_name$IsMutable();\n"
     "  for ($type$ value : values) {\n"
-    "    $name$_.add(value.getNumber());\n"
+    "    $name$_.addInt(value.getNumber());\n"
     "  }\n"
     "}\n");
   WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "private void clear$capitalized_name$() {\n"
-    "  $name$_ = emptyProtobufList();\n"
+    "  $name$_ = emptyIntList();\n"
     "}\n");
 
   if (SupportUnknownEnumValue(descriptor_->file())) {
@@ -692,13 +690,13 @@ GenerateMembers(io::Printer* printer) const {
       "private void set$capitalized_name$Value(\n"
       "    int index, int value) {\n"
       "  ensure$capitalized_name$IsMutable();\n"
-      "  $name$_.set(index, value);\n"
+      "  $name$_.setInt(index, value);\n"
       "}\n");
     WriteFieldDocComment(printer, descriptor_);
     printer->Print(variables_,
       "private void add$capitalized_name$Value(int value) {\n"
       "  ensure$capitalized_name$IsMutable();\n"
-      "  $name$_.add(value);\n"
+      "  $name$_.addInt(value);\n"
       "}\n");
     WriteFieldDocComment(printer, descriptor_);
     printer->Print(variables_,
@@ -706,7 +704,7 @@ GenerateMembers(io::Printer* printer) const {
       "    java.lang.Iterable<java.lang.Integer> values) {\n"
       "  ensure$capitalized_name$IsMutable();\n"
       "  for (int value : values) {\n"
-      "    $name$_.add(value);\n"
+      "    $name$_.addInt(value);\n"
       "  }\n"
       "}\n");
   }
@@ -805,7 +803,7 @@ GenerateFieldBuilderInitializationCode(io::Printer* printer)  const {
 
 void RepeatedImmutableEnumFieldLiteGenerator::
 GenerateInitializationCode(io::Printer* printer) const {
-  printer->Print(variables_, "$name$_ = emptyProtobufList();\n");
+  printer->Print(variables_, "$name$_ = emptyIntList();\n");
 }
 
 void RepeatedImmutableEnumFieldLiteGenerator::
@@ -840,9 +838,9 @@ GenerateParsingCode(io::Printer* printer) const {
     printer->Print(variables_,
       "int rawValue = input.readEnum();\n"
       "if (!$is_mutable$) {\n"
-      "  $name$_ = newProtobufList();\n"
+      "  $name$_ = newIntList();\n"
       "}\n"
-      "$name$_.add(rawValue);\n");
+      "$name$_.addInt(rawValue);\n");
   } else {
     printer->Print(variables_,
       "int rawValue = input.readEnum();\n"
@@ -855,9 +853,9 @@ GenerateParsingCode(io::Printer* printer) const {
     printer->Print(variables_,
       "} else {\n"
       "  if (!$is_mutable$) {\n"
-      "    $name$_ = newProtobufList();\n"
+      "    $name$_ = newIntList();\n"
       "  }\n"
-      "  $name$_.add(rawValue);\n"
+      "  $name$_.addInt(rawValue);\n"
       "}\n");
   }
 }
@@ -897,12 +895,12 @@ GenerateSerializationCode(io::Printer* printer) const {
       "  output.writeRawVarint32($name$MemoizedSerializedSize);\n"
       "}\n"
       "for (int i = 0; i < $name$_.size(); i++) {\n"
-      "  output.writeEnumNoTag($name$_.get(i));\n"
+      "  output.writeEnumNoTag($name$_.getInt(i));\n"
       "}\n");
   } else {
     printer->Print(variables_,
       "for (int i = 0; i < $name$_.size(); i++) {\n"
-      "  output.writeEnum($number$, $name$_.get(i));\n"
+      "  output.writeEnum($number$, $name$_.getInt(i));\n"
       "}\n");
   }
 }
@@ -917,7 +915,7 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
   printer->Print(variables_,
     "for (int i = 0; i < $name$_.size(); i++) {\n"
     "  dataSize += com.google.protobuf.CodedOutputStream\n"
-    "    .computeEnumSizeNoTag($name$_.get(i));\n"
+    "    .computeEnumSizeNoTag($name$_.getInt(i));\n"
     "}\n");
   printer->Print(
     "size += dataSize;\n");
diff --git a/src/google/protobuf/compiler/java/java_enum_lite.cc b/src/google/protobuf/compiler/java/java_enum_lite.cc
index 62186386..ed415eee 100644
--- a/src/google/protobuf/compiler/java/java_enum_lite.cc
+++ b/src/google/protobuf/compiler/java/java_enum_lite.cc
@@ -85,34 +85,26 @@ EnumLiteGenerator::~EnumLiteGenerator() {}
 
 void EnumLiteGenerator::Generate(io::Printer* printer) {
   WriteEnumDocComment(printer, descriptor_);
-  if (HasDescriptorMethods(descriptor_)) {
-    printer->Print(
-      "public enum $classname$\n"
-      "    implements com.google.protobuf.ProtocolMessageEnum {\n",
-      "classname", descriptor_->name());
-  } else {
-    printer->Print(
-      "public enum $classname$\n"
-      "    implements com.google.protobuf.Internal.EnumLite {\n",
-      "classname", descriptor_->name());
-  }
+  printer->Print(
+    "public enum $classname$\n"
+    "    implements com.google.protobuf.Internal.EnumLite {\n",
+    "classname", descriptor_->name());
   printer->Indent();
 
   for (int i = 0; i < canonical_values_.size(); i++) {
     map<string, string> vars;
     vars["name"] = canonical_values_[i]->name();
-    vars["index"] = SimpleItoa(canonical_values_[i]->index());
     vars["number"] = SimpleItoa(canonical_values_[i]->number());
     WriteEnumValueDocComment(printer, canonical_values_[i]);
     if (canonical_values_[i]->options().deprecated()) {
       printer->Print("@java.lang.Deprecated\n");
     }
     printer->Print(vars,
-      "$name$($index$, $number$),\n");
+      "$name$($number$),\n");
   }
 
   if (SupportUnknownEnumValue(descriptor_->file())) {
-    printer->Print("UNRECOGNIZED(-1, -1),\n");
+    printer->Print("UNRECOGNIZED(-1),\n");
   }
 
   printer->Print(
@@ -145,15 +137,7 @@ void EnumLiteGenerator::Generate(io::Printer* printer) {
 
   printer->Print(
     "\n"
-    "public final int getNumber() {\n");
-  if (SupportUnknownEnumValue(descriptor_->file())) {
-    printer->Print(
-      "  if (index == -1) {\n"
-      "    throw new java.lang.IllegalArgumentException(\n"
-      "        \"Can't get the number of an unknown enum value.\");\n"
-      "  }\n");
-  }
-  printer->Print(
+    "public final int getNumber() {\n"
     "  return value;\n"
     "}\n"
     "\n"
@@ -193,7 +177,7 @@ void EnumLiteGenerator::Generate(io::Printer* printer) {
 
   printer->Print(
     "private final int value;\n\n"
-    "private $classname$(int index, int value) {\n",
+    "private $classname$(int value) {\n",
     "classname", descriptor_->name());
   printer->Print(
     "  this.value = value;\n"
diff --git a/src/google/protobuf/compiler/java/java_file.cc b/src/google/protobuf/compiler/java/java_file.cc
index 68b47ee1..c8172330 100644
--- a/src/google/protobuf/compiler/java/java_file.cc
+++ b/src/google/protobuf/compiler/java/java_file.cc
@@ -42,6 +42,7 @@
 
 #include <google/protobuf/compiler/java/java_context.h>
 #include <google/protobuf/compiler/java/java_enum.h>
+#include <google/protobuf/compiler/java/java_enum_lite.h>
 #include <google/protobuf/compiler/java/java_extension.h>
 #include <google/protobuf/compiler/java/java_generator_factory.h>
 #include <google/protobuf/compiler/java/java_helpers.h>
@@ -281,8 +282,13 @@ void FileGenerator::Generate(io::Printer* printer) {
 
   if (!MultipleJavaFiles(file_, immutable_api_)) {
     for (int i = 0; i < file_->enum_type_count(); i++) {
-      EnumGenerator(file_->enum_type(i), immutable_api_, context_.get())
-          .Generate(printer);
+      if (HasDescriptorMethods(file_)) {
+        EnumGenerator(file_->enum_type(i), immutable_api_, context_.get())
+            .Generate(printer);
+      } else {
+        EnumLiteGenerator(file_->enum_type(i), immutable_api_, context_.get())
+            .Generate(printer);
+      }
     }
     for (int i = 0; i < file_->message_type_count(); i++) {
       message_generators_[i]->GenerateInterface(printer);
@@ -543,13 +549,23 @@ void FileGenerator::GenerateSiblings(const string& package_dir,
                                      vector<string>* file_list) {
   if (MultipleJavaFiles(file_, immutable_api_)) {
     for (int i = 0; i < file_->enum_type_count(); i++) {
-      EnumGenerator generator(file_->enum_type(i), immutable_api_,
-                              context_.get());
-      GenerateSibling<EnumGenerator>(package_dir, java_package_,
-                                     file_->enum_type(i),
-                                     context, file_list, "",
-                                     &generator,
-                                     &EnumGenerator::Generate);
+      if (HasDescriptorMethods(file_)) {
+        EnumGenerator generator(file_->enum_type(i), immutable_api_,
+                                context_.get());
+        GenerateSibling<EnumGenerator>(package_dir, java_package_,
+                                       file_->enum_type(i),
+                                       context, file_list, "",
+                                       &generator,
+                                       &EnumGenerator::Generate);
+      } else {
+        EnumLiteGenerator generator(file_->enum_type(i), immutable_api_,
+                                    context_.get());
+        GenerateSibling<EnumLiteGenerator>(package_dir, java_package_,
+                                           file_->enum_type(i),
+                                           context, file_list, "",
+                                           &generator,
+                                           &EnumLiteGenerator::Generate);
+      }
     }
     for (int i = 0; i < file_->message_type_count(); i++) {
       if (immutable_api_) {
diff --git a/src/google/protobuf/compiler/java/java_primitive_field_lite.cc b/src/google/protobuf/compiler/java/java_primitive_field_lite.cc
index 392333b8..5a7bf82d 100644
--- a/src/google/protobuf/compiler/java/java_primitive_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_primitive_field_lite.cc
@@ -87,11 +87,13 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
       (*variables)["field_list_type"] =
           "com.google.protobuf.Internal." + capitalized_type + "List";
       (*variables)["new_list"] = "new" + capitalized_type + "List";
+      (*variables)["new_list_with_capacity"] =
+          "new" + capitalized_type + "ListWithCapacity";
       (*variables)["empty_list"] = "empty" + capitalized_type + "List()";
       (*variables)["make_name_unmodifiable"] =
           (*variables)["name"] + "_.makeImmutable()";
-      (*variables)["repeated_index_get"] =
-          (*variables)["name"] + "_.get" + capitalized_type + "(index)";
+      (*variables)["repeated_get"] =
+          (*variables)["name"] + "_.get" + capitalized_type;
       (*variables)["repeated_add"] =
           (*variables)["name"] + "_.add" + capitalized_type;
       (*variables)["repeated_set"] =
@@ -102,11 +104,11 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
           "com.google.protobuf.Internal.ProtobufList<" +
           (*variables)["boxed_type"] + ">";
       (*variables)["new_list"] = "newProtobufList";
+      (*variables)["new_list_with_capacity"] = "newProtobufListWithCapacity";
       (*variables)["empty_list"] = "emptyProtobufList()";
       (*variables)["make_name_unmodifiable"] =
           (*variables)["name"] + "_.makeImmutable()";
-      (*variables)["repeated_index_get"] =
-          (*variables)["name"] + "_.get(index)";
+      (*variables)["repeated_get"] = (*variables)["name"] + "_.get";
       (*variables)["repeated_add"] = (*variables)["name"] + "_.add";
       (*variables)["repeated_set"] = (*variables)["name"] + "_.set";
   }
@@ -629,7 +631,7 @@ GenerateMembers(io::Printer* printer) const {
   WriteFieldDocComment(printer, descriptor_);
   printer->Print(variables_,
     "$deprecation$public $type$ get$capitalized_name$(int index) {\n"
-    "  return $repeated_index_get$;\n"
+    "  return $repeated_get$(index);\n"
     "}\n");
 
   if (descriptor_->options().packed() &&
@@ -773,6 +775,9 @@ GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const {
 
 void RepeatedImmutablePrimitiveFieldLiteGenerator::
 GenerateParsingCode(io::Printer* printer) const {
+  // TODO(dweis): Scan the input buffer to count, then initialize
+  // appropriately.
+  // TODO(dweis): Scan the input buffer to count and ensure capacity.
   printer->Print(variables_,
     "if (!$is_mutable$) {\n"
     "  $name$_ = $new_list$();\n"
@@ -785,8 +790,21 @@ GenerateParsingCodeFromPacked(io::Printer* printer) const {
   printer->Print(variables_,
     "int length = input.readRawVarint32();\n"
     "int limit = input.pushLimit(length);\n"
-    "if (!$is_mutable$ && input.getBytesUntilLimit() > 0) {\n"
-    "  $name$_ = $new_list$();\n"
+    "if (!$is_mutable$ && input.getBytesUntilLimit() > 0) {\n");
+
+  int fixed_size = FixedSize(GetType(descriptor_));
+  if (fixed_size == -1) {
+    // TODO(dweis): Scan the input buffer to count, then initialize
+    // appropriately.
+    printer->Print(variables_,
+      "  $name$_ = $new_list$();\n");
+  } else {
+    printer->Print(variables_,
+      "  $name$_ = $new_list_with_capacity$(length/$fixed_size$);\n");
+  }
+
+  // TODO(dweis): Scan the input buffer to count and ensure capacity.
+  printer->Print(variables_,
     "}\n"
     "while (input.getBytesUntilLimit() > 0) {\n"
     "  $repeated_add$(input.read$capitalized_type$());\n"
@@ -814,12 +832,12 @@ GenerateSerializationCode(io::Printer* printer) const {
       "  output.writeRawVarint32($name$MemoizedSerializedSize);\n"
       "}\n"
       "for (int i = 0; i < $name$_.size(); i++) {\n"
-      "  output.write$capitalized_type$NoTag($name$_.get(i));\n"
+      "  output.write$capitalized_type$NoTag($repeated_get$(i));\n"
       "}\n");
   } else {
     printer->Print(variables_,
       "for (int i = 0; i < $name$_.size(); i++) {\n"
-      "  output.write$capitalized_type$($number$, $name$_.get(i));\n"
+      "  output.write$capitalized_type$($number$, $repeated_get$(i));\n"
       "}\n");
   }
 }
@@ -835,7 +853,7 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
     printer->Print(variables_,
       "for (int i = 0; i < $name$_.size(); i++) {\n"
       "  dataSize += com.google.protobuf.CodedOutputStream\n"
-      "    .compute$capitalized_type$SizeNoTag($name$_.get(i));\n"
+      "    .compute$capitalized_type$SizeNoTag($repeated_get$(i));\n"
       "}\n");
   } else {
     printer->Print(variables_,
diff --git a/src/google/protobuf/compiler/java/java_string_field.cc b/src/google/protobuf/compiler/java/java_string_field.cc
index 72ebaeca..7f757e47 100644
--- a/src/google/protobuf/compiler/java/java_string_field.cc
+++ b/src/google/protobuf/compiler/java/java_string_field.cc
@@ -405,7 +405,7 @@ void ImmutableStringFieldGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   if (CheckUtf8(descriptor_)) {
     printer->Print(variables_,
-      "String s = input.readStringRequireUtf8();\n"
+      "java.lang.String s = input.readStringRequireUtf8();\n"
       "$set_has_field_bit_message$\n"
       "$name$_ = s;\n");
   } else if (!HasDescriptorMethods(descriptor_->file())) {
@@ -414,7 +414,7 @@ GenerateParsingCode(io::Printer* printer) const {
     // spurious intermediary ByteString allocations, cutting overall allocations
     // in half.
     printer->Print(variables_,
-      "String s = input.readString();\n"
+      "java.lang.String s = input.readString();\n"
       "$set_has_field_bit_message$\n"
       "$name$_ = s;\n");
   } else {
@@ -665,7 +665,7 @@ void ImmutableStringOneofFieldGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   if (CheckUtf8(descriptor_)) {
     printer->Print(variables_,
-      "String s = input.readStringRequireUtf8();\n"
+      "java.lang.String s = input.readStringRequireUtf8();\n"
       "$set_oneof_case_message$;\n"
       "$oneof_name$_ = s;\n");
   } else if (!HasDescriptorMethods(descriptor_->file())) {
@@ -674,7 +674,7 @@ GenerateParsingCode(io::Printer* printer) const {
     // spurious intermediary ByteString allocations, cutting overall allocations
     // in half.
     printer->Print(variables_,
-      "String s = input.readString();\n"
+      "java.lang.String s = input.readString();\n"
       "$set_oneof_case_message$;\n"
       "$oneof_name$_ = s;\n");
   } else {
@@ -773,12 +773,6 @@ GenerateMembers(io::Printer* printer) const {
     "    get$capitalized_name$Bytes(int index) {\n"
     "  return $name$_.getByteString(index);\n"
     "}\n");
-
-  if (descriptor_->options().packed() &&
-      HasGeneratedMethods(descriptor_->containing_type())) {
-    printer->Print(variables_,
-      "private int $name$MemoizedSerializedSize = -1;\n");
-  }
 }
 
 void RepeatedImmutableStringFieldGenerator::
@@ -939,14 +933,14 @@ void RepeatedImmutableStringFieldGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   if (CheckUtf8(descriptor_)) {
     printer->Print(variables_,
-    "String s = input.readStringRequireUtf8();\n");
+    "java.lang.String s = input.readStringRequireUtf8();\n");
   } else if (!HasDescriptorMethods(descriptor_->file())) {
     // Lite runtime should attempt to reduce allocations by attempting to
     // construct the string directly from the input stream buffer. This avoids
     // spurious intermediary ByteString allocations, cutting overall allocations
     // in half.
     printer->Print(variables_,
-    "String s = input.readString();\n");
+    "java.lang.String s = input.readString();\n");
   } else {
     printer->Print(variables_,
     "com.google.protobuf.ByteString bs = input.readBytes();\n");
@@ -966,30 +960,6 @@ GenerateParsingCode(io::Printer* printer) const {
 }
 
 void RepeatedImmutableStringFieldGenerator::
-GenerateParsingCodeFromPacked(io::Printer* printer) const {
-  printer->Print(variables_,
-    "int length = input.readRawVarint32();\n"
-    "int limit = input.pushLimit(length);\n"
-    "if (!$get_mutable_bit_parser$ && input.getBytesUntilLimit() > 0) {\n"
-    "  $name$_ = new com.google.protobuf.LazyStringArrayList();\n"
-    "  $set_mutable_bit_parser$;\n"
-    "}\n"
-    "while (input.getBytesUntilLimit() > 0) {\n");
-  if (CheckUtf8(descriptor_)) {
-    printer->Print(variables_,
-      "  String s = input.readStringRequireUtf8();\n");
-  } else {
-    printer->Print(variables_,
-      "  String s = input.readString();\n");
-  }
-  printer->Print(variables_,
-    "  $name$.add(s);\n");
-  printer->Print(variables_,
-    "}\n"
-    "input.popLimit(limit);\n");
-}
-
-void RepeatedImmutableStringFieldGenerator::
 GenerateParsingDoneCode(io::Printer* printer) const {
   printer->Print(variables_,
     "if ($get_mutable_bit_parser$) {\n"
@@ -999,21 +969,10 @@ GenerateParsingDoneCode(io::Printer* printer) const {
 
 void RepeatedImmutableStringFieldGenerator::
 GenerateSerializationCode(io::Printer* printer) const {
-  if (descriptor_->options().packed()) {
-    printer->Print(variables_,
-      "if (get$capitalized_name$List().size() > 0) {\n"
-      "  output.writeRawVarint32($tag$);\n"
-      "  output.writeRawVarint32($name$MemoizedSerializedSize);\n"
-      "}\n"
-      "for (int i = 0; i < $name$_.size(); i++) {\n"
-      "  writeStringNoTag(output, $name$_.getRaw(i));\n"
-      "}\n");
-  } else {
-    printer->Print(variables_,
-      "for (int i = 0; i < $name$_.size(); i++) {\n"
-      "  $writeString$(output, $number$, $name$_.getRaw(i));\n"
-      "}\n");
-  }
+  printer->Print(variables_,
+    "for (int i = 0; i < $name$_.size(); i++) {\n"
+    "  $writeString$(output, $number$, $name$_.getRaw(i));\n"
+    "}\n");
 }
 
 void RepeatedImmutableStringFieldGenerator::
@@ -1031,23 +990,8 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
   printer->Print(
       "size += dataSize;\n");
 
-  if (descriptor_->options().packed()) {
-    printer->Print(variables_,
-      "if (!get$capitalized_name$List().isEmpty()) {\n"
-      "  size += $tag_size$;\n"
-      "  size += com.google.protobuf.CodedOutputStream\n"
-      "      .computeInt32SizeNoTag(dataSize);\n"
-      "}\n");
-  } else {
-    printer->Print(variables_,
-      "size += $tag_size$ * get$capitalized_name$List().size();\n");
-  }
-
-  // cache the data size for packed fields.
-  if (descriptor_->options().packed()) {
-    printer->Print(variables_,
-      "$name$MemoizedSerializedSize = dataSize;\n");
-  }
+  printer->Print(variables_,
+    "size += $tag_size$ * get$capitalized_name$List().size();\n");
 
   printer->Outdent();
   printer->Print("}\n");
diff --git a/src/google/protobuf/compiler/java/java_string_field.h b/src/google/protobuf/compiler/java/java_string_field.h
index 1ea44dec..a3b57351 100644
--- a/src/google/protobuf/compiler/java/java_string_field.h
+++ b/src/google/protobuf/compiler/java/java_string_field.h
@@ -131,7 +131,6 @@ class RepeatedImmutableStringFieldGenerator : public ImmutableFieldGenerator {
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
-  void GenerateParsingCodeFromPacked(io::Printer* printer) const;
   void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/java/java_string_field_lite.cc b/src/google/protobuf/compiler/java/java_string_field_lite.cc
index 092e3c29..eb5964bd 100644
--- a/src/google/protobuf/compiler/java/java_string_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_string_field_lite.cc
@@ -647,12 +647,6 @@ GenerateMembers(io::Printer* printer) const {
     "      $name$_.get(index));\n"
     "}\n");
 
-  if (descriptor_->options().packed() &&
-      HasGeneratedMethods(descriptor_->containing_type())) {
-    printer->Print(variables_,
-      "private int $name$MemoizedSerializedSize = -1;\n");
-  }
-
   printer->Print(variables_,
     "private void ensure$capitalized_name$IsMutable() {\n"
     "  if (!$is_mutable$) {\n"
@@ -835,29 +829,6 @@ GenerateParsingCode(io::Printer* printer) const {
 }
 
 void RepeatedImmutableStringFieldLiteGenerator::
-GenerateParsingCodeFromPacked(io::Printer* printer) const {
-  printer->Print(variables_,
-    "int length = input.readRawVarint32();\n"
-    "int limit = input.pushLimit(length);\n"
-    "if (!$is_mutable$ && input.getBytesUntilLimit() > 0) {\n"
-    "  $name$_ = com.google.protobuf.GeneratedMessageLite.newProtobufList();\n"
-    "}\n"
-    "while (input.getBytesUntilLimit() > 0) {\n");
-  if (CheckUtf8(descriptor_)) {
-    printer->Print(variables_,
-      "  String s = input.readStringRequireUtf8();\n");
-  } else {
-    printer->Print(variables_,
-      "  String s = input.readString();\n");
-  }
-  printer->Print(variables_,
-    "  $name$.add(s);\n");
-  printer->Print(variables_,
-    "}\n"
-    "input.popLimit(limit);\n");
-}
-
-void RepeatedImmutableStringFieldLiteGenerator::
 GenerateParsingDoneCode(io::Printer* printer) const {
   printer->Print(variables_,
     "if ($is_mutable$) {\n"
@@ -870,21 +841,10 @@ GenerateSerializationCode(io::Printer* printer) const {
   // Lite runtime should reduce allocations by serializing the string directly.
   // This avoids spurious intermediary ByteString allocations, cutting overall
   // allocations in half.
-  if (descriptor_->options().packed()) {
-    printer->Print(variables_,
-      "if (get$capitalized_name$List().size() > 0) {\n"
-      "  output.writeRawVarint32($tag$);\n"
-      "  output.writeRawVarint32($name$MemoizedSerializedSize);\n"
-      "}\n"
-      "for (int i = 0; i < $name$_.size(); i++) {\n"
-      "  output.writeStringNoTag($name$_.get(i));\n"
-      "}\n");
-  } else {
-    printer->Print(variables_,
-      "for (int i = 0; i < $name$_.size(); i++) {\n"
-      "  output.writeString($number$, $name$_.get(i));\n"
-      "}\n");
-  }
+  printer->Print(variables_,
+    "for (int i = 0; i < $name$_.size(); i++) {\n"
+    "  output.writeString($number$, $name$_.get(i));\n"
+    "}\n");
 }
 
 void RepeatedImmutableStringFieldLiteGenerator::
@@ -906,23 +866,9 @@ GenerateSerializedSizeCode(io::Printer* printer) const {
   printer->Print(
       "size += dataSize;\n");
 
-  if (descriptor_->options().packed()) {
-    printer->Print(variables_,
-      "if (!get$capitalized_name$List().isEmpty()) {\n"
-      "  size += $tag_size$;\n"
-      "  size += com.google.protobuf.CodedOutputStream\n"
-      "      .computeInt32SizeNoTag(dataSize);\n"
-      "}\n");
-  } else {
-    printer->Print(variables_,
-      "size += $tag_size$ * get$capitalized_name$List().size();\n");
-  }
 
-  // cache the data size for packed fields.
-  if (descriptor_->options().packed()) {
-    printer->Print(variables_,
-      "$name$MemoizedSerializedSize = dataSize;\n");
-  }
+  printer->Print(variables_,
+    "size += $tag_size$ * get$capitalized_name$List().size();\n");
 
   printer->Outdent();
   printer->Print("}\n");
diff --git a/src/google/protobuf/compiler/java/java_string_field_lite.h b/src/google/protobuf/compiler/java/java_string_field_lite.h
index 9d93b307..4d9b4bd7 100644
--- a/src/google/protobuf/compiler/java/java_string_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_string_field_lite.h
@@ -129,7 +129,6 @@ class RepeatedImmutableStringFieldLiteGenerator
   void GenerateMergingCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
-  void GenerateParsingCodeFromPacked(io::Printer* printer) const;
   void GenerateParsingDoneCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/js/js_generator.cc b/src/google/protobuf/compiler/js/js_generator.cc
new file mode 100755
index 00000000..1e308464
--- /dev/null
+++ b/src/google/protobuf/compiler/js/js_generator.cc
@@ -0,0 +1,2620 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <google/protobuf/compiler/js/js_generator.h>
+
+#include <assert.h>
+#include <algorithm>
+#include <limits>
+#include <map>
+#include <memory>
+#ifndef _SHARED_PTR_H
+#include <google/protobuf/stubs/shared_ptr.h>
+#endif
+#include <string>
+#include <utility>
+#include <vector>
+
+#include <google/protobuf/stubs/logging.h>
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/stringprintf.h>
+#include <google/protobuf/io/printer.h>
+#include <google/protobuf/io/zero_copy_stream.h>
+#include <google/protobuf/descriptor.pb.h>
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/stubs/strutil.h>
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace js {
+
+// Sorted list of JavaScript keywords. These cannot be used as names. If they
+// appear, we prefix them with "pb_".
+const char* kKeyword[] = {
+  "abstract",
+  "boolean",
+  "break",
+  "byte",
+  "case",
+  "catch",
+  "char",
+  "class",
+  "const",
+  "continue",
+  "debugger",
+  "default",
+  "delete",
+  "do",
+  "double",
+  "else",
+  "enum",
+  "export",
+  "extends",
+  "false",
+  "final",
+  "finally",
+  "float",
+  "for",
+  "function",
+  "goto",
+  "if",
+  "implements",
+  "import",
+  "in",
+  "instanceof",
+  "int",
+  "interface",
+  "long",
+  "native",
+  "new",
+  "null",
+  "package",
+  "private",
+  "protected",
+  "public",
+  "return",
+  "short",
+  "static",
+  "super",
+  "switch",
+  "synchronized",
+  "this",
+  "throw",
+  "throws",
+  "transient",
+  "try",
+  "typeof",
+  "var",
+  "void",
+  "volatile",
+  "while",
+  "with",
+};
+
+static const int kNumKeyword = sizeof(kKeyword) / sizeof(char*);
+
+namespace {
+
+bool IsReserved(const string& ident) {
+  for (int i = 0; i < kNumKeyword; i++) {
+    if (ident == kKeyword[i]) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Returns a copy of |filename| with any trailing ".protodevel" or ".proto
+// suffix stripped.
+string StripProto(const string& filename) {
+  const char* suffix = HasSuffixString(filename, ".protodevel")
+      ? ".protodevel" : ".proto";
+  return StripSuffixString(filename, suffix);
+}
+
+// Returns the fully normalized JavaScript path for the given
+// file descriptor's package.
+string GetPath(const GeneratorOptions& options,
+               const FileDescriptor* file) {
+  if (!options.namespace_prefix.empty()) {
+    return options.namespace_prefix;
+  } else if (!file->package().empty()) {
+    return "proto." + file->package();
+  } else {
+    return "proto";
+  }
+}
+
+// Forward declare, so that GetPrefix can call this method,
+// which in turn, calls GetPrefix.
+string GetPath(const GeneratorOptions& options,
+               const Descriptor* descriptor);
+
+// Returns the path prefix for a message or enumeration that
+// lives under the given file and containing type.
+string GetPrefix(const GeneratorOptions& options,
+                 const FileDescriptor* file_descriptor,
+                 const Descriptor* containing_type) {
+  string prefix = "";
+
+  if (containing_type == NULL) {
+    prefix = GetPath(options, file_descriptor);
+  } else {
+    prefix = GetPath(options, containing_type);
+  }
+
+  if (!prefix.empty()) {
+    prefix += ".";
+  }
+
+  return prefix;
+}
+
+
+// Returns the fully normalized JavaScript path for the given
+// message descriptor.
+string GetPath(const GeneratorOptions& options,
+               const Descriptor* descriptor) {
+  return GetPrefix(
+      options, descriptor->file(),
+      descriptor->containing_type()) + descriptor->name();
+}
+
+
+// Returns the fully normalized JavaScript path for the given
+// field's containing message descriptor.
+string GetPath(const GeneratorOptions& options,
+               const FieldDescriptor* descriptor) {
+  return GetPath(options, descriptor->containing_type());
+}
+
+// Returns the fully normalized JavaScript path for the given
+// enumeration descriptor.
+string GetPath(const GeneratorOptions& options,
+               const EnumDescriptor* enum_descriptor) {
+  return GetPrefix(
+      options, enum_descriptor->file(),
+      enum_descriptor->containing_type()) + enum_descriptor->name();
+}
+
+
+// Returns the fully normalized JavaScript path for the given
+// enumeration value descriptor.
+string GetPath(const GeneratorOptions& options,
+               const EnumValueDescriptor* value_descriptor) {
+  return GetPath(
+      options,
+      value_descriptor->type()) + "." + value_descriptor->name();
+}
+
+// - Object field name: LOWER_UNDERSCORE -> LOWER_CAMEL, except for group fields
+// (UPPER_CAMEL -> LOWER_CAMEL), with "List" (or "Map") appended if appropriate,
+// and with reserved words triggering a "pb_" prefix.
+// - Getters/setters: LOWER_UNDERSCORE -> UPPER_CAMEL, except for group fields
+// (use the name directly), then append "List" if appropriate, then append "$"
+// if resulting name is equal to a reserved word.
+// - Enums: just uppercase.
+
+// Locale-independent version of ToLower that deals only with ASCII A-Z.
+char ToLowerASCII(char c) {
+  if (c >= 'A' && c <= 'Z') {
+    return (c - 'A') + 'a';
+  } else {
+    return c;
+  }
+}
+
+vector<string> ParseLowerUnderscore(const string& input) {
+  vector<string> words;
+  string running = "";
+  for (int i = 0; i < input.size(); i++) {
+    if (input[i] == '_') {
+      if (!running.empty()) {
+        words.push_back(running);
+        running.clear();
+      }
+    } else {
+      running += ToLowerASCII(input[i]);
+    }
+  }
+  if (!running.empty()) {
+    words.push_back(running);
+  }
+  return words;
+}
+
+vector<string> ParseUpperCamel(const string& input) {
+  vector<string> words;
+  string running = "";
+  for (int i = 0; i < input.size(); i++) {
+    if (input[i] >= 'A' && input[i] <= 'Z' && !running.empty()) {
+      words.push_back(running);
+      running.clear();
+    }
+    running += ToLowerASCII(input[i]);
+  }
+  if (!running.empty()) {
+    words.push_back(running);
+  }
+  return words;
+}
+
+string ToLowerCamel(const vector<string>& words) {
+  string result;
+  for (int i = 0; i < words.size(); i++) {
+    string word = words[i];
+    if (i == 0 && (word[0] >= 'A' && word[0] <= 'Z')) {
+      word[0] = (word[0] - 'A') + 'a';
+    } else if (i != 0 && (word[0] >= 'a' && word[0] <= 'z')) {
+      word[0] = (word[0] - 'a') + 'A';
+    }
+    result += word;
+  }
+  return result;
+}
+
+string ToUpperCamel(const vector<string>& words) {
+  string result;
+  for (int i = 0; i < words.size(); i++) {
+    string word = words[i];
+    if (word[0] >= 'a' && word[0] <= 'z') {
+      word[0] = (word[0] - 'a') + 'A';
+    }
+    result += word;
+  }
+  return result;
+}
+
+// Based on code from descriptor.cc (Thanks Kenton!)
+// Uppercases the entire string, turning ValueName into
+// VALUENAME.
+string ToEnumCase(const string& input) {
+  string result;
+  result.reserve(input.size());
+
+  for (int i = 0; i < input.size(); i++) {
+    if ('a' <= input[i] && input[i] <= 'z') {
+      result.push_back(input[i] - 'a' + 'A');
+    } else {
+      result.push_back(input[i]);
+    }
+  }
+
+  return result;
+}
+
+string ToFileName(const string& input) {
+  string result;
+  result.reserve(input.size());
+
+  for (int i = 0; i < input.size(); i++) {
+    if ('A' <= input[i] && input[i] <= 'Z') {
+      result.push_back(input[i] - 'A' + 'a');
+    } else {
+      result.push_back(input[i]);
+    }
+  }
+
+  return result;
+}
+
+// Returns the message/response ID, if set.
+string GetMessageId(const Descriptor* desc) {
+  return string();
+}
+
+
+// Used inside Google only -- do not remove.
+bool IsResponse(const Descriptor* desc) { return false; }
+bool IgnoreField(const FieldDescriptor* field) { return false; }
+
+
+// Does JSPB ignore this entire oneof? True only if all fields are ignored.
+bool IgnoreOneof(const OneofDescriptor* oneof) {
+  for (int i = 0; i < oneof->field_count(); i++) {
+    if (!IgnoreField(oneof->field(i))) {
+      return false;
+    }
+  }
+  return true;
+}
+
+string JSIdent(const FieldDescriptor* field,
+               bool is_upper_camel,
+               bool is_map) {
+  string result;
+  if (field->type() == FieldDescriptor::TYPE_GROUP) {
+    result = is_upper_camel ?
+        ToUpperCamel(ParseUpperCamel(field->message_type()->name())) :
+        ToLowerCamel(ParseUpperCamel(field->message_type()->name()));
+  } else {
+    result = is_upper_camel ?
+        ToUpperCamel(ParseLowerUnderscore(field->name())) :
+        ToLowerCamel(ParseLowerUnderscore(field->name()));
+  }
+  if (is_map) {
+    result += "Map";
+  } else if (field->is_repeated()) {
+    result += "List";
+  }
+  return result;
+}
+
+string JSObjectFieldName(const FieldDescriptor* field) {
+  string name = JSIdent(
+      field,
+      /* is_upper_camel = */ false,
+      /* is_map = */ false);
+  if (IsReserved(name)) {
+    name = "pb_" + name;
+  }
+  return name;
+}
+
+// Returns the field name as a capitalized portion of a getter/setter method
+// name, e.g. MyField for .getMyField().
+string JSGetterName(const FieldDescriptor* field) {
+  string name = JSIdent(field,
+                        /* is_upper_camel = */ true,
+                        /* is_map = */ false);
+  if (name == "Extension" || name == "JsPbMessageId") {
+    // Avoid conflicts with base-class names.
+    name += "$";
+  }
+  return name;
+}
+
+string JSMapGetterName(const FieldDescriptor* field) {
+  return JSIdent(field,
+                 /* is_upper_camel = */ true,
+                 /* is_map = */ true);
+}
+
+
+
+string JSOneofName(const OneofDescriptor* oneof) {
+  return ToUpperCamel(ParseLowerUnderscore(oneof->name()));
+}
+
+// Returns the index corresponding to this field in the JSPB array (underlying
+// data storage array).
+string JSFieldIndex(const FieldDescriptor* field) {
+  // Determine whether this field is a member of a group. Group fields are a bit
+  // wonky: their "containing type" is a message type created just for the
+  // group, and that type's parent type has a field with the group-message type
+  // as its message type and TYPE_GROUP as its field type. For such fields, the
+  // index we use is relative to the field number of the group submessage field.
+  // For all other fields, we just use the field number.
+  const Descriptor* containing_type = field->containing_type();
+  const Descriptor* parent_type = containing_type->containing_type();
+  if (parent_type != NULL) {
+    for (int i = 0; i < parent_type->field_count(); i++) {
+      if (parent_type->field(i)->type() == FieldDescriptor::TYPE_GROUP &&
+          parent_type->field(i)->message_type() == containing_type) {
+        return SimpleItoa(field->number() - parent_type->field(i)->number());
+      }
+    }
+  }
+  return SimpleItoa(field->number());
+}
+
+string JSOneofIndex(const OneofDescriptor* oneof) {
+  int index = -1;
+  for (int i = 0; i < oneof->containing_type()->oneof_decl_count(); i++) {
+    const OneofDescriptor* o = oneof->containing_type()->oneof_decl(i);
+    // If at least one field in this oneof is not JSPB-ignored, count the oneof.
+    for (int j = 0; j < o->field_count(); j++) {
+      const FieldDescriptor* f = o->field(j);
+      if (!IgnoreField(f)) {
+        index++;
+        break;  // inner loop
+      }
+    }
+    if (o == oneof) {
+      break;
+    }
+  }
+  return SimpleItoa(index);
+}
+
+// Decodes a codepoint in \x0000 -- \xFFFF. Since JS strings are UTF-16, we only
+// need to handle the BMP (16-bit range) here.
+uint16_t DecodeUTF8Codepoint(uint8_t* bytes, size_t* length) {
+  if (*length == 0) {
+    return 0;
+  }
+  size_t expected = 0;
+  if ((*bytes & 0x80) == 0) {
+    expected = 1;
+  } else if ((*bytes & 0xe0) == 0xc0) {
+    expected = 2;
+  } else if ((*bytes & 0xf0) == 0xe0) {
+    expected = 3;
+  } else {
+    // Too long -- don't accept.
+    *length = 0;
+    return 0;
+  }
+
+  if (*length < expected) {
+    // Not enough bytes -- don't accept.
+    *length = 0;
+    return 0;
+  }
+
+  *length = expected;
+  switch (expected) {
+    case 1: return bytes[0];
+    case 2: return ((bytes[0] & 0x1F) << 6)  |
+                   ((bytes[1] & 0x3F) << 0);
+    case 3: return ((bytes[0] & 0x0F) << 12) |
+                   ((bytes[1] & 0x3F) << 6)  |
+                   ((bytes[2] & 0x3F) << 0);
+    default: return 0;
+  }
+}
+
+// Escapes the contents of a string to be included within double-quotes ("") in
+// JavaScript. |is_utf8| determines whether the input data (in a C++ string of
+// chars) is UTF-8 encoded (in which case codepoints become JavaScript string
+// characters, escaped with 16-bit hex escapes where necessary) or raw binary
+// (in which case bytes become JavaScript string characters 0 -- 255).
+string EscapeJSString(const string& in, bool is_utf8) {
+  string result;
+  size_t decoded = 0;
+  for (size_t i = 0; i < in.size(); i += decoded) {
+    uint16_t codepoint = 0;
+    if (is_utf8) {
+      // Decode the next UTF-8 codepoint.
+      size_t have_bytes = in.size() - i;
+      uint8_t bytes[3] = {
+        static_cast<uint8_t>(in[i]),
+        static_cast<uint8_t>(((i + 1) < in.size()) ? in[i + 1] : 0),
+        static_cast<uint8_t>(((i + 2) < in.size()) ? in[i + 2] : 0),
+      };
+      codepoint = DecodeUTF8Codepoint(bytes, &have_bytes);
+      if (have_bytes == 0) {
+        break;
+      }
+      decoded = have_bytes;
+    } else {
+      codepoint = static_cast<uint16_t>(static_cast<uint8_t>(in[i]));
+      decoded = 1;
+    }
+
+    // Next byte -- used for minimal octal escapes below.
+    char next_byte = (i + decoded) < in.size() ?
+        in[i + decoded] : 0;
+    bool pad_octal = (next_byte >= '0' && next_byte <= '7');
+
+    switch (codepoint) {
+      case '\0': result += pad_octal ? "\\000" : "\\0";   break;
+      case '\b': result += "\\\b";  break;
+      case '\t': result += "\\\t";  break;
+      case '\n': result += "\\\n";  break;
+      case '\r': result += "\\\r";  break;
+      case '\f': result += "\\\f";  break;
+      case '\\': result += "\\\\";  break;
+      case '"':  result += pad_octal ? "\\042" : "\\42"; break;
+      case '&':  result += pad_octal ? "\\046" : "\\46"; break;
+      case '\'': result += pad_octal ? "\\047" : "\\47"; break;
+      case '<':  result += pad_octal ? "\\074" : "\\74"; break;
+      case '=':  result += pad_octal ? "\\075" : "\\75"; break;
+      case '>':  result += pad_octal ? "\\076" : "\\76"; break;
+      default:
+        // All other non-ASCII codepoints are escaped.
+        // Original codegen uses hex for >= 0x100 and octal for others.
+        if (codepoint >= 0x20 && codepoint <= 0x7e) {
+          result += static_cast<char>(codepoint);
+        } else {
+          if (codepoint >= 0x100) {
+            result += StringPrintf("\\u%04x", codepoint);
+          } else {
+            if (pad_octal || codepoint >= 0100) {
+              result += "\\";
+              result += ('0' + ((codepoint >> 6) & 07));
+              result += ('0' + ((codepoint >> 3) & 07));
+              result += ('0' + ((codepoint >> 0) & 07));
+            } else if (codepoint >= 010) {
+              result += "\\";
+              result += ('0' + ((codepoint >> 3) & 07));
+              result += ('0' + ((codepoint >> 0) & 07));
+            } else {
+              result += "\\";
+              result += ('0' + ((codepoint >> 0) & 07));
+            }
+          }
+        }
+        break;
+    }
+  }
+  return result;
+}
+
+string EscapeBase64(const string& in) {
+  static const char* kAlphabet =
+      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+  string result;
+
+  for (size_t i = 0; i < in.size(); i += 3) {
+    int value = (in[i] << 16) |
+        (((i + 1) < in.size()) ? (in[i + 1] << 8) : 0) |
+        (((i + 2) < in.size()) ? (in[i + 2] << 0) : 0);
+    result += kAlphabet[(value >> 18) & 0x3f];
+    result += kAlphabet[(value >> 12) & 0x3f];
+    if ((i + 1) < in.size()) {
+      result += kAlphabet[(value >>  6) & 0x3f];
+    } else {
+      result += '=';
+    }
+    if ((i + 2) < in.size()) {
+      result += kAlphabet[(value >>  0) & 0x3f];
+    } else {
+      result += '=';
+    }
+  }
+
+  return result;
+}
+
+// Post-process the result of SimpleFtoa/SimpleDtoa to *exactly* match the
+// original codegen's formatting (which is just .toString() on java.lang.Double
+// or java.lang.Float).
+string PostProcessFloat(string result) {
+  // If inf, -inf or nan, replace with +Infinity, -Infinity or NaN.
+  if (result == "inf") {
+    return "Infinity";
+  } else if (result == "-inf") {
+    return "-Infinity";
+  } else if (result == "nan") {
+    return "NaN";
+  }
+
+  // If scientific notation (e.g., "1e10"), (i) capitalize the "e", (ii)
+  // ensure that the mantissa (portion prior to the "e") has at least one
+  // fractional digit (after the decimal point), and (iii) strip any unnecessary
+  // leading zeroes and/or '+' signs from the exponent.
+  string::size_type exp_pos = result.find('e');
+  if (exp_pos != string::npos) {
+    string mantissa = result.substr(0, exp_pos);
+    string exponent = result.substr(exp_pos + 1);
+
+    // Add ".0" to mantissa if no fractional part exists.
+    if (mantissa.find('.') == string::npos) {
+      mantissa += ".0";
+    }
+
+    // Strip the sign off the exponent and store as |exp_neg|.
+    bool exp_neg = false;
+    if (!exponent.empty() && exponent[0] == '+') {
+      exponent = exponent.substr(1);
+    } else if (!exponent.empty() && exponent[0] == '-') {
+      exp_neg = true;
+      exponent = exponent.substr(1);
+    }
+
+    // Strip any leading zeroes off the exponent.
+    while (exponent.size() > 1 && exponent[0] == '0') {
+      exponent = exponent.substr(1);
+    }
+
+    return mantissa + "E" + string(exp_neg ? "-" : "") + exponent;
+  }
+
+  // Otherwise, this is an ordinary decimal number. Append ".0" if result has no
+  // decimal/fractional part in order to match output of original codegen.
+  if (result.find('.') == string::npos) {
+    result += ".0";
+  }
+
+  return result;
+}
+
+string FloatToString(float value) {
+  string result = SimpleFtoa(value);
+  return PostProcessFloat(result);
+}
+
+string DoubleToString(double value) {
+  string result = SimpleDtoa(value);
+  return PostProcessFloat(result);
+}
+
+string MaybeNumberString(const FieldDescriptor* field, const string& orig) {
+  return orig;
+}
+
+string JSFieldDefault(const FieldDescriptor* field) {
+  assert(field->has_default_value());
+  switch (field->cpp_type()) {
+    case FieldDescriptor::CPPTYPE_INT32:
+      return MaybeNumberString(
+          field, SimpleItoa(field->default_value_int32()));
+    case FieldDescriptor::CPPTYPE_UINT32:
+      // The original codegen is in Java, and Java protobufs store unsigned
+      // integer values as signed integer values. In order to exactly match the
+      // output, we need to reinterpret as base-2 signed. Ugh.
+      return MaybeNumberString(
+          field, SimpleItoa(static_cast<int32>(field->default_value_uint32())));
+    case FieldDescriptor::CPPTYPE_INT64:
+      return MaybeNumberString(
+          field, SimpleItoa(field->default_value_int64()));
+    case FieldDescriptor::CPPTYPE_UINT64:
+      // See above note for uint32 -- reinterpreting as signed.
+      return MaybeNumberString(
+          field, SimpleItoa(static_cast<int64>(field->default_value_uint64())));
+    case FieldDescriptor::CPPTYPE_ENUM:
+      return SimpleItoa(field->default_value_enum()->number());
+    case FieldDescriptor::CPPTYPE_BOOL:
+      return field->default_value_bool() ? "true" : "false";
+    case FieldDescriptor::CPPTYPE_FLOAT:
+      return FloatToString(field->default_value_float());
+    case FieldDescriptor::CPPTYPE_DOUBLE:
+      return DoubleToString(field->default_value_double());
+    case FieldDescriptor::CPPTYPE_STRING:
+      if (field->type() == FieldDescriptor::TYPE_STRING) {
+        return "\"" + EscapeJSString(field->default_value_string(), true) +
+               "\"";
+      } else {
+        return "\"" + EscapeBase64(field->default_value_string()) +
+               "\"";
+      }
+    case FieldDescriptor::CPPTYPE_MESSAGE:
+      return "null";
+  }
+}
+
+string ProtoTypeName(const GeneratorOptions& options,
+                     const FieldDescriptor* field) {
+  switch (field->type()) {
+    case FieldDescriptor::TYPE_BOOL:
+      return "bool";
+    case FieldDescriptor::TYPE_INT32:
+      return "int32";
+    case FieldDescriptor::TYPE_UINT32:
+      return "uint32";
+    case FieldDescriptor::TYPE_SINT32:
+      return "sint32";
+    case FieldDescriptor::TYPE_FIXED32:
+      return "fixed32";
+    case FieldDescriptor::TYPE_SFIXED32:
+      return "sfixed32";
+    case FieldDescriptor::TYPE_INT64:
+      return "int64";
+    case FieldDescriptor::TYPE_UINT64:
+      return "uint64";
+    case FieldDescriptor::TYPE_SINT64:
+      return "sint64";
+    case FieldDescriptor::TYPE_FIXED64:
+      return "fixed64";
+    case FieldDescriptor::TYPE_SFIXED64:
+      return "sfixed64";
+    case FieldDescriptor::TYPE_FLOAT:
+      return "float";
+    case FieldDescriptor::TYPE_DOUBLE:
+      return "double";
+    case FieldDescriptor::TYPE_STRING:
+      return "string";
+    case FieldDescriptor::TYPE_BYTES:
+      return "bytes";
+    case FieldDescriptor::TYPE_GROUP:
+      return GetPath(options, field->message_type());
+    case FieldDescriptor::TYPE_ENUM:
+      return GetPath(options, field->enum_type());
+    case FieldDescriptor::TYPE_MESSAGE:
+      return GetPath(options, field->message_type());
+    default:
+      return "";
+  }
+}
+
+string JSIntegerTypeName(const FieldDescriptor* field) {
+  return "number";
+}
+
+string JSTypeName(const GeneratorOptions& options,
+                  const FieldDescriptor* field) {
+  switch (field->cpp_type()) {
+    case FieldDescriptor::CPPTYPE_BOOL:
+      return "boolean";
+    case FieldDescriptor::CPPTYPE_INT32:
+      return JSIntegerTypeName(field);
+    case FieldDescriptor::CPPTYPE_INT64:
+      return JSIntegerTypeName(field);
+    case FieldDescriptor::CPPTYPE_UINT32:
+      return JSIntegerTypeName(field);
+    case FieldDescriptor::CPPTYPE_UINT64:
+      return JSIntegerTypeName(field);
+    case FieldDescriptor::CPPTYPE_FLOAT:
+      return "number";
+    case FieldDescriptor::CPPTYPE_DOUBLE:
+      return "number";
+    case FieldDescriptor::CPPTYPE_STRING:
+      return "string";
+    case FieldDescriptor::CPPTYPE_ENUM:
+      return GetPath(options, field->enum_type());
+    case FieldDescriptor::CPPTYPE_MESSAGE:
+      return GetPath(options, field->message_type());
+    default:
+      return "";
+  }
+}
+
+bool HasFieldPresence(const FieldDescriptor* field);
+
+string JSFieldTypeAnnotation(const GeneratorOptions& options,
+                             const FieldDescriptor* field,
+                             bool force_optional,
+                             bool force_present,
+                             bool singular_if_not_packed,
+                             bool always_singular) {
+  bool is_primitive =
+      (field->cpp_type() != FieldDescriptor::CPPTYPE_ENUM &&
+       field->cpp_type() != FieldDescriptor::CPPTYPE_MESSAGE);
+
+  string jstype = JSTypeName(options, field);
+
+  if (field->is_repeated() &&
+      !always_singular &&
+      (field->is_packed() || !singular_if_not_packed)) {
+    if (!is_primitive) {
+      jstype = "!" + jstype;
+    }
+    jstype = "Array.<" + jstype + ">";
+    if (!force_optional) {
+      jstype = "!" + jstype;
+    }
+  }
+
+  if (field->is_optional() && is_primitive &&
+      (!field->has_default_value() || force_optional) && !force_present) {
+    jstype += "?";
+  } else if (field->is_required() && !is_primitive && !force_optional) {
+    jstype = "!" + jstype;
+  }
+
+  if (force_optional && HasFieldPresence(field)) {
+    jstype += "|undefined";
+  }
+  if (force_present && jstype[0] != '!' && !is_primitive) {
+    jstype = "!" + jstype;
+  }
+
+  return jstype;
+}
+
+string JSBinaryReaderMethodType(const FieldDescriptor* field) {
+  string name = field->type_name();
+  if (name[0] >= 'a' && name[0] <= 'z') {
+    name[0] = (name[0] - 'a') + 'A';
+  }
+
+  return name;
+}
+
+string JSBinaryReadWriteMethodName(const FieldDescriptor* field,
+                                   bool is_writer) {
+  string name = JSBinaryReaderMethodType(field);
+  if (is_writer && field->type() == FieldDescriptor::TYPE_BYTES) {
+    // Override for `bytes` fields: treat string as raw bytes, not base64.
+    name = "BytesRawString";
+  }
+  if (field->is_packed()) {
+    name = "Packed" + name;
+  } else if (is_writer && field->is_repeated()) {
+    name = "Repeated" + name;
+  }
+  return name;
+}
+
+string JSBinaryReaderMethodName(const FieldDescriptor* field) {
+  return "read" + JSBinaryReadWriteMethodName(field, /* is_writer = */ false);
+}
+
+string JSBinaryWriterMethodName(const FieldDescriptor* field) {
+  return "write" + JSBinaryReadWriteMethodName(field, /* is_writer = */ true);
+}
+
+string JSReturnClause(const FieldDescriptor* desc) {
+  return "";
+}
+
+string JSReturnDoc(const GeneratorOptions& options,
+                   const FieldDescriptor* desc) {
+  return "";
+}
+
+bool HasRepeatedFields(const Descriptor* desc) {
+  for (int i = 0; i < desc->field_count(); i++) {
+    if (desc->field(i)->is_repeated()) {
+      return true;
+    }
+  }
+  return false;
+}
+
+static const char* kRepeatedFieldArrayName = ".repeatedFields_";
+
+string RepeatedFieldsArrayName(const GeneratorOptions& options,
+                               const Descriptor* desc) {
+  return HasRepeatedFields(desc) ?
+      (GetPath(options, desc) + kRepeatedFieldArrayName) : "null";
+}
+
+bool HasOneofFields(const Descriptor* desc) {
+  for (int i = 0; i < desc->field_count(); i++) {
+    if (desc->field(i)->containing_oneof()) {
+      return true;
+    }
+  }
+  return false;
+}
+
+static const char* kOneofGroupArrayName = ".oneofGroups_";
+
+string OneofFieldsArrayName(const GeneratorOptions& options,
+                            const Descriptor* desc) {
+  return HasOneofFields(desc) ?
+      (GetPath(options, desc) + kOneofGroupArrayName) : "null";
+}
+
+string RepeatedFieldNumberList(const Descriptor* desc) {
+  std::vector<string> numbers;
+  for (int i = 0; i < desc->field_count(); i++) {
+    if (desc->field(i)->is_repeated()) {
+      numbers.push_back(JSFieldIndex(desc->field(i)));
+    }
+  }
+  return "[" + Join(numbers, ",") + "]";
+}
+
+string OneofGroupList(const Descriptor* desc) {
+  // List of arrays (one per oneof), each of which is a list of field indices
+  std::vector<string> oneof_entries;
+  for (int i = 0; i < desc->oneof_decl_count(); i++) {
+    const OneofDescriptor* oneof = desc->oneof_decl(i);
+    if (IgnoreOneof(oneof)) {
+      continue;
+    }
+
+    std::vector<string> oneof_fields;
+    for (int j = 0; j < oneof->field_count(); j++) {
+      if (IgnoreField(oneof->field(j))) {
+        continue;
+      }
+      oneof_fields.push_back(JSFieldIndex(oneof->field(j)));
+    }
+    oneof_entries.push_back("[" + Join(oneof_fields, ",") + "]");
+  }
+  return "[" + Join(oneof_entries, ",") + "]";
+}
+
+string JSOneofArray(const GeneratorOptions& options,
+                    const FieldDescriptor* field) {
+  return OneofFieldsArrayName(options, field->containing_type()) + "[" +
+      JSOneofIndex(field->containing_oneof()) + "]";
+}
+
+string RelativeTypeName(const FieldDescriptor* field) {
+  assert(field->cpp_type() == FieldDescriptor::CPPTYPE_ENUM ||
+         field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE);
+  // For a field with an enum or message type, compute a name relative to the
+  // path name of the message type containing this field.
+  string package = field->file()->package();
+  string containing_type = field->containing_type()->full_name() + ".";
+  string type = (field->cpp_type() == FieldDescriptor::CPPTYPE_ENUM) ?
+      field->enum_type()->full_name() : field->message_type()->full_name();
+
+  // |prefix| is advanced as we find separators '.' past the common package
+  // prefix that yield common prefixes in the containing type's name and this
+  // type's name.
+  int prefix = 0;
+  for (int i = 0; i < type.size() && i < containing_type.size(); i++) {
+    if (type[i] != containing_type[i]) {
+      break;
+    }
+    if (type[i] == '.' && i >= package.size()) {
+      prefix = i + 1;
+    }
+  }
+
+  return type.substr(prefix);
+}
+
+string JSExtensionsObjectName(const GeneratorOptions& options,
+                              const Descriptor* desc) {
+  if (desc->full_name() == "google.protobuf.bridge.MessageSet") {
+    return "jspb.Message.messageSetExtensions";
+  } else {
+    return GetPath(options, desc) + ".extensions";
+  }
+}
+
+string FieldDefinition(const GeneratorOptions& options,
+                       const FieldDescriptor* field) {
+  string qualifier = field->is_repeated() ? "repeated" :
+      (field->is_optional() ? "optional" : "required");
+  string type, name;
+  if (field->type() == FieldDescriptor::TYPE_ENUM ||
+      field->type() == FieldDescriptor::TYPE_MESSAGE) {
+    type = RelativeTypeName(field);
+    name = field->name();
+  } else if (field->type() == FieldDescriptor::TYPE_GROUP) {
+    type = "group";
+    name = field->message_type()->name();
+  } else {
+    type = ProtoTypeName(options, field);
+    name = field->name();
+  }
+  return StringPrintf("%s %s %s = %d;",
+                      qualifier.c_str(),
+                      type.c_str(),
+                      name.c_str(),
+                      field->number());
+}
+
+string FieldComments(const FieldDescriptor* field) {
+  string comments;
+  if (field->cpp_type() == FieldDescriptor::CPPTYPE_BOOL) {
+    comments +=
+        " * Note that Boolean fields may be set to 0/1 when serialized from "
+        "a Java server.\n"
+        " * You should avoid comparisons like {@code val === true/false} in "
+        "those cases.\n";
+  }
+  if (field->is_repeated()) {
+    comments +=
+        " * If you change this array by adding, removing or replacing "
+        "elements, or if you\n"
+        " * replace the array itself, then you must call the setter to "
+        "update it.\n";
+  }
+  return comments;
+}
+
+bool ShouldGenerateExtension(const FieldDescriptor* field) {
+  return
+      field->is_extension() &&
+      !IgnoreField(field);
+}
+
+bool HasExtensions(const Descriptor* desc) {
+  if (desc->extension_count() > 0) {
+    return true;
+  }
+  for (int i = 0; i < desc->nested_type_count(); i++) {
+    if (HasExtensions(desc->nested_type(i))) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool HasExtensions(const FileDescriptor* file) {
+  for (int i = 0; i < file->extension_count(); i++) {
+    if (ShouldGenerateExtension(file->extension(i))) {
+      return true;
+    }
+  }
+  for (int i = 0; i < file->message_type_count(); i++) {
+    if (HasExtensions(file->message_type(i))) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool IsExtendable(const Descriptor* desc) {
+  return desc->extension_range_count() > 0;
+}
+
+// Returns the max index in the underlying data storage array beyond which the
+// extension object is used.
+string GetPivot(const Descriptor* desc) {
+  static const int kDefaultPivot = (1 << 29);  // max field number (29 bits)
+
+  // Find the max field number
+  int max_field_number = 0;
+  for (int i = 0; i < desc->field_count(); i++) {
+    if (!IgnoreField(desc->field(i)) &&
+        desc->field(i)->number() > max_field_number) {
+      max_field_number = desc->field(i)->number();
+    }
+  }
+
+  int pivot = -1;
+  if (IsExtendable(desc)) {
+    pivot = ((max_field_number + 1) < kDefaultPivot) ?
+        (max_field_number + 1) : kDefaultPivot;
+  }
+
+  return SimpleItoa(pivot);
+}
+
+// Returns true for fields that represent "null" as distinct from the default
+// value. See https://go/proto3#heading=h.kozewqqcqhuz for more information.
+bool HasFieldPresence(const FieldDescriptor* field) {
+  return
+      (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) ||
+      (field->containing_oneof() != NULL) ||
+      (field->file()->syntax() != FileDescriptor::SYNTAX_PROTO3);
+}
+
+// For proto3 fields without presence, returns a string representing the default
+// value in JavaScript. See https://go/proto3#heading=h.kozewqqcqhuz for more
+// information.
+string Proto3PrimitiveFieldDefault(const FieldDescriptor* field) {
+  switch (field->cpp_type()) {
+    case FieldDescriptor::CPPTYPE_INT32:
+    case FieldDescriptor::CPPTYPE_INT64:
+    case FieldDescriptor::CPPTYPE_UINT32:
+    case FieldDescriptor::CPPTYPE_UINT64: {
+      return "0";
+    }
+
+    case FieldDescriptor::CPPTYPE_ENUM:
+    case FieldDescriptor::CPPTYPE_FLOAT:
+    case FieldDescriptor::CPPTYPE_DOUBLE:
+      return "0";
+
+    case FieldDescriptor::CPPTYPE_BOOL:
+      return "false";
+
+    case FieldDescriptor::CPPTYPE_STRING:
+      return "\"\"";
+
+    default:
+      // BYTES and MESSAGE are handled separately.
+      assert(false);
+      return "";
+  }
+}
+
+}  // anonymous namespace
+
+void Generator::GenerateHeader(const GeneratorOptions& options,
+                               io::Printer* printer) const {
+  printer->Print("/**\n"
+                 " * @fileoverview\n"
+                 " * @enhanceable\n"
+                 " * @public\n"
+                 " */\n"
+                 "// GENERATED CODE -- DO NOT EDIT!\n"
+                 "\n");
+}
+
+void Generator::FindProvides(const GeneratorOptions& options,
+                             io::Printer* printer,
+                             const vector<const FileDescriptor*>& files,
+                             std::set<string>* provided) const {
+  for (int i = 0; i < files.size(); i++) {
+    for (int j = 0; j < files[i]->message_type_count(); j++) {
+      FindProvidesForMessage(options, printer, files[i]->message_type(j),
+                                 provided);
+    }
+    for (int j = 0; j < files[i]->enum_type_count(); j++) {
+      FindProvidesForEnum(options, printer, files[i]->enum_type(j),
+                              provided);
+    }
+  }
+
+  printer->Print("\n");
+}
+
+void Generator::FindProvidesForMessage(
+    const GeneratorOptions& options,
+    io::Printer* printer,
+    const Descriptor* desc,
+    std::set<string>* provided) const {
+  string name = GetPath(options, desc);
+  provided->insert(name);
+
+  for (int i = 0; i < desc->enum_type_count(); i++) {
+    FindProvidesForEnum(options, printer, desc->enum_type(i),
+                        provided);
+  }
+  for (int i = 0; i < desc->nested_type_count(); i++) {
+    FindProvidesForMessage(options, printer, desc->nested_type(i),
+                           provided);
+  }
+}
+
+void Generator::FindProvidesForEnum(const GeneratorOptions& options,
+                                    io::Printer* printer,
+                                    const EnumDescriptor* enumdesc,
+                                    std::set<string>* provided) const {
+  string name = GetPath(options, enumdesc);
+  provided->insert(name);
+}
+
+void Generator::FindProvidesForFields(
+    const GeneratorOptions& options,
+    io::Printer* printer,
+    const vector<const FieldDescriptor*>& fields,
+    std::set<string>* provided) const {
+  for (int i = 0; i < fields.size(); i++) {
+    const FieldDescriptor* field = fields[i];
+
+    if (IgnoreField(field)) {
+      continue;
+    }
+
+    string name =
+        GetPath(options, field->file()) + "." + JSObjectFieldName(field);
+    provided->insert(name);
+  }
+}
+
+void Generator::GenerateProvides(const GeneratorOptions& options,
+                                 io::Printer* printer,
+                                 std::set<string>* provided) const {
+  for (std::set<string>::iterator it = provided->begin();
+       it != provided->end(); ++it) {
+    printer->Print("goog.provide('$name$');\n",
+                   "name", *it);
+  }
+}
+
+void Generator::GenerateRequires(const GeneratorOptions& options,
+                                 io::Printer* printer,
+                                 const Descriptor* desc,
+                                 std::set<string>* provided) const {
+  std::set<string> required;
+  std::set<string> forwards;
+  bool have_message = false;
+  FindRequiresForMessage(options, desc,
+                         &required, &forwards, &have_message);
+
+  GenerateRequiresImpl(options, printer, &required, &forwards, provided,
+                       /* require_jspb = */ have_message,
+                       /* require_extension = */ HasExtensions(desc));
+}
+
+void Generator::GenerateRequires(const GeneratorOptions& options,
+                                 io::Printer* printer,
+                                 const vector<const FileDescriptor*>& files,
+                                 std::set<string>* provided) const {
+  std::set<string> required;
+  std::set<string> forwards;
+  bool have_extensions = false;
+  bool have_message = false;
+
+  for (int i = 0; i < files.size(); i++) {
+    for (int j = 0; j < files[i]->message_type_count(); j++) {
+      FindRequiresForMessage(options,
+                             files[i]->message_type(j),
+                             &required, &forwards, &have_message);
+    }
+    if (!have_extensions && HasExtensions(files[i])) {
+      have_extensions = true;
+    }
+
+    for (int j = 0; j < files[i]->extension_count(); j++) {
+      const FieldDescriptor* extension = files[i]->extension(j);
+      if (IgnoreField(extension)) {
+        continue;
+      }
+      if (extension->containing_type()->full_name() !=
+          "google.protobuf.bridge.MessageSet") {
+        required.insert(GetPath(options, extension->containing_type()));
+      }
+      FindRequiresForField(options, extension, &required, &forwards);
+      have_extensions = true;
+    }
+  }
+
+  GenerateRequiresImpl(options, printer, &required, &forwards, provided,
+                       /* require_jspb = */ have_message,
+                       /* require_extension = */ have_extensions);
+}
+
+void Generator::GenerateRequires(const GeneratorOptions& options,
+                                 io::Printer* printer,
+                                 const vector<const FieldDescriptor*>& fields,
+                                 std::set<string>* provided) const {
+  std::set<string> required;
+  std::set<string> forwards;
+  for (int i = 0; i < fields.size(); i++) {
+    const FieldDescriptor* field = fields[i];
+    if (IgnoreField(field)) {
+      continue;
+    }
+    FindRequiresForExtension(options, field, &required, &forwards);
+  }
+
+  GenerateRequiresImpl(options, printer, &required, &forwards, provided,
+                       /* require_jspb = */ false,
+                       /* require_extension = */ fields.size() > 0);
+}
+
+void Generator::GenerateRequiresImpl(const GeneratorOptions& options,
+                                     io::Printer* printer,
+                                     std::set<string>* required,
+                                     std::set<string>* forwards,
+                                     std::set<string>* provided,
+                                     bool require_jspb,
+                                     bool require_extension) const {
+  if (require_jspb) {
+    printer->Print(
+        "goog.require('jspb.Message');\n");
+    if (options.binary) {
+      printer->Print(
+          "goog.require('jspb.BinaryReader');\n"
+          "goog.require('jspb.BinaryWriter');\n");
+    }
+  }
+  if (require_extension) {
+    printer->Print(
+        "goog.require('jspb.ExtensionFieldInfo');\n");
+  }
+
+  std::set<string>::iterator it;
+  for (it = required->begin(); it != required->end(); ++it) {
+    if (provided->find(*it) != provided->end()) {
+      continue;
+    }
+    printer->Print("goog.require('$name$');\n",
+                   "name", *it);
+  }
+
+  printer->Print("\n");
+
+  for (it = forwards->begin(); it != forwards->end(); ++it) {
+    if (provided->find(*it) != provided->end()) {
+      continue;
+    }
+    printer->Print("goog.forwardDeclare('$name$');\n",
+                   "name", *it);
+  }
+}
+
+bool NamespaceOnly(const Descriptor* desc) {
+  return false;
+}
+
+void Generator::FindRequiresForMessage(
+    const GeneratorOptions& options,
+    const Descriptor* desc,
+    std::set<string>* required,
+    std::set<string>* forwards,
+    bool* have_message) const {
+
+
+  if (!NamespaceOnly(desc)) {
+    *have_message = true;
+    for (int i = 0; i < desc->field_count(); i++) {
+      const FieldDescriptor* field = desc->field(i);
+      if (IgnoreField(field)) {
+        continue;
+      }
+      FindRequiresForField(options, field, required, forwards);
+    }
+  }
+
+  for (int i = 0; i < desc->extension_count(); i++) {
+    const FieldDescriptor* field = desc->extension(i);
+    if (IgnoreField(field)) {
+      continue;
+    }
+    FindRequiresForExtension(options, field, required, forwards);
+  }
+
+  for (int i = 0; i < desc->nested_type_count(); i++) {
+    FindRequiresForMessage(options, desc->nested_type(i), required, forwards,
+                           have_message);
+  }
+}
+
+void Generator::FindRequiresForField(const GeneratorOptions& options,
+                                     const FieldDescriptor* field,
+                                     std::set<string>* required,
+                                     std::set<string>* forwards) const {
+    if (field->cpp_type() == FieldDescriptor::CPPTYPE_ENUM &&
+        // N.B.: file-level extensions with enum type do *not* create
+        // dependencies, as per original codegen.
+        !(field->is_extension() && field->extension_scope() == NULL)) {
+      if (options.add_require_for_enums) {
+        required->insert(GetPath(options, field->enum_type()));
+      } else {
+        forwards->insert(GetPath(options, field->enum_type()));
+      }
+    } else if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+      required->insert(GetPath(options, field->message_type()));
+    }
+}
+
+void Generator::FindRequiresForExtension(const GeneratorOptions& options,
+                                         const FieldDescriptor* field,
+                                         std::set<string>* required,
+                                         std::set<string>* forwards) const {
+    if (field->containing_type()->full_name() != "google.protobuf.bridge.MessageSet") {
+      required->insert(GetPath(options, field->containing_type()));
+    }
+    FindRequiresForField(options, field, required, forwards);
+}
+
+void Generator::GenerateTestOnly(const GeneratorOptions& options,
+                                 io::Printer* printer) const {
+  if (options.testonly) {
+    printer->Print("goog.setTestOnly();\n\n");
+  }
+  printer->Print("\n");
+}
+
+void Generator::GenerateClassesAndEnums(const GeneratorOptions& options,
+                                        io::Printer* printer,
+                                        const FileDescriptor* file) const {
+  for (int i = 0; i < file->message_type_count(); i++) {
+    GenerateClass(options, printer, file->message_type(i));
+  }
+  for (int i = 0; i < file->enum_type_count(); i++) {
+    GenerateEnum(options, printer, file->enum_type(i));
+  }
+}
+
+void Generator::GenerateClass(const GeneratorOptions& options,
+                              io::Printer* printer,
+                              const Descriptor* desc) const {
+  if (!NamespaceOnly(desc)) {
+    printer->Print("\n");
+    GenerateClassConstructor(options, printer, desc);
+    GenerateClassFieldInfo(options, printer, desc);
+
+
+    GenerateClassToObject(options, printer, desc);
+    if (options.binary) {
+      // These must come *before* the extension-field info generation in
+      // GenerateClassRegistration so that references to the binary
+      // serialization/deserialization functions may be placed in the extension
+      // objects.
+      GenerateClassDeserializeBinary(options, printer, desc);
+      GenerateClassSerializeBinary(options, printer, desc);
+    }
+    GenerateClassClone(options, printer, desc);
+    GenerateClassRegistration(options, printer, desc);
+    GenerateClassFields(options, printer, desc);
+    if (IsExtendable(desc) && desc->full_name() != "google.protobuf.bridge.MessageSet") {
+      GenerateClassExtensionFieldInfo(options, printer, desc);
+    }
+  }
+
+  // Recurse on nested types.
+  for (int i = 0; i < desc->enum_type_count(); i++) {
+    GenerateEnum(options, printer, desc->enum_type(i));
+  }
+  for (int i = 0; i < desc->nested_type_count(); i++) {
+    GenerateClass(options, printer, desc->nested_type(i));
+  }
+}
+
+void Generator::GenerateClassConstructor(const GeneratorOptions& options,
+                                         io::Printer* printer,
+                                         const Descriptor* desc) const {
+  printer->Print(
+      "/**\n"
+      " * Generated by JsPbCodeGenerator.\n"
+      " * @param {Array=} opt_data Optional initial data array, typically "
+      "from a\n"
+      " * server response, or constructed directly in Javascript. The array "
+      "is used\n"
+      " * in place and becomes part of the constructed object. It is not "
+      "cloned.\n"
+      " * If no data is provided, the constructed object will be empty, but "
+      "still\n"
+      " * valid.\n"
+      " * @extends {jspb.Message}\n"
+      " * @constructor\n"
+      " */\n"
+      "$classname$ = function(opt_data) {\n",
+      "classname", GetPath(options, desc));
+  string message_id = GetMessageId(desc);
+  printer->Print(
+      "  jspb.Message.initialize(this, opt_data, $messageId$, $pivot$, "
+      "$rptfields$, $oneoffields$);\n",
+      "messageId", !message_id.empty() ?
+                   ("'" + message_id + "'") :
+                   (IsResponse(desc) ? "''" : "0"),
+      "pivot", GetPivot(desc),
+      "rptfields", RepeatedFieldsArrayName(options, desc),
+      "oneoffields", OneofFieldsArrayName(options, desc));
+  printer->Print(
+      "};\n"
+      "goog.inherits($classname$, jspb.Message);\n"
+      "if (goog.DEBUG && !COMPILED) {\n"
+      "  $classname$.displayName = '$classname$';\n"
+      "}\n",
+      "classname", GetPath(options, desc));
+}
+
+void Generator::GenerateClassFieldInfo(const GeneratorOptions& options,
+                                       io::Printer* printer,
+                                       const Descriptor* desc) const {
+  if (HasRepeatedFields(desc)) {
+    printer->Print(
+        "/**\n"
+        " * List of repeated fields within this message type.\n"
+        " * @private {!Array<number>}\n"
+        " * @const\n"
+        " */\n"
+        "$classname$$rptfieldarray$ = $rptfields$;\n"
+        "\n",
+        "classname", GetPath(options, desc),
+        "rptfieldarray", kRepeatedFieldArrayName,
+        "rptfields", RepeatedFieldNumberList(desc));
+  }
+
+  if (HasOneofFields(desc)) {
+    printer->Print(
+        "/**\n"
+        " * Oneof group definitions for this message. Each group defines the "
+        "field\n"
+        " * numbers belonging to that group. When of these fields' value is "
+        "set, all\n"
+        " * other fields in the group are cleared. During deserialization, if "
+        "multiple\n"
+        " * fields are encountered for a group, only the last value seen will "
+        "be kept.\n"
+        " * @private {!Array<!Array<number>>}\n"
+        " * @const\n"
+        " */\n"
+        "$classname$$oneofgrouparray$ = $oneofgroups$;\n"
+        "\n",
+        "classname", GetPath(options, desc),
+        "oneofgrouparray", kOneofGroupArrayName,
+        "oneofgroups", OneofGroupList(desc));
+
+    for (int i = 0; i < desc->oneof_decl_count(); i++) {
+      if (IgnoreOneof(desc->oneof_decl(i))) {
+        continue;
+      }
+      GenerateOneofCaseDefinition(options, printer, desc->oneof_decl(i));
+    }
+  }
+}
+
+void Generator::GenerateClassXid(const GeneratorOptions& options,
+                                 io::Printer* printer,
+                                 const Descriptor* desc) const {
+  printer->Print(
+      "\n"
+      "\n"
+      "$class$.prototype.messageXid = xid('$class$');\n",
+      "class", GetPath(options, desc));
+}
+
+void Generator::GenerateOneofCaseDefinition(
+    const GeneratorOptions& options,
+    io::Printer* printer,
+    const OneofDescriptor* oneof) const {
+  printer->Print(
+      "/**\n"
+      " * @enum {number}\n"
+      " */\n"
+      "$classname$.$oneof$Case = {\n"
+      "  $upcase$_NOT_SET: 0",
+      "classname", GetPath(options, oneof->containing_type()),
+      "oneof", JSOneofName(oneof),
+      "upcase", ToEnumCase(oneof->name()));
+
+  for (int i = 0; i < oneof->field_count(); i++) {
+    if (IgnoreField(oneof->field(i))) {
+      continue;
+    }
+
+    printer->Print(
+        ",\n"
+        "  $upcase$: $number$",
+        "upcase", ToEnumCase(oneof->field(i)->name()),
+        "number", JSFieldIndex(oneof->field(i)));
+  }
+
+  printer->Print(
+      "\n"
+      "};\n"
+      "\n"
+      "/**\n"
+      " * @return {$class$.$oneof$Case}\n"
+      " */\n"
+      "$class$.prototype.get$oneof$Case = function() {\n"
+      "  return /** @type {$class$.$oneof$Case} */(jspb.Message."
+      "computeOneofCase(this, $class$.oneofGroups_[$oneofindex$]));\n"
+      "};\n"
+      "\n",
+      "class", GetPath(options, oneof->containing_type()),
+      "oneof", JSOneofName(oneof),
+      "oneofindex", JSOneofIndex(oneof));
+}
+
+void Generator::GenerateClassToObject(const GeneratorOptions& options,
+                                      io::Printer* printer,
+                                      const Descriptor* desc) const {
+  printer->Print(
+      "\n"
+      "\n"
+      "if (jspb.Message.GENERATE_TO_OBJECT) {\n"
+      "/**\n"
+      " * Creates an object representation of this proto suitable for use in "
+      "Soy templates.\n"
+      " * Field names that are reserved in JavaScript and will be renamed to "
+      "pb_name.\n"
+      " * To access a reserved field use, foo.pb_<name>, eg, foo.pb_default.\n"
+      " * For the list of reserved names please see:\n"
+      " *     com.google.apps.jspb.JsClassTemplate.JS_RESERVED_WORDS.\n"
+      " * @param {boolean=} opt_includeInstance Whether to include the JSPB "
+      "instance\n"
+      " *     for transitional soy proto support: http://goto/soy-param-"
+      "migration\n"
+      " * @return {!Object}\n"
+      " */\n"
+      "$classname$.prototype.toObject = function(opt_includeInstance) {\n"
+      "  return $classname$.toObject(opt_includeInstance, this);\n"
+      "};\n"
+      "\n"
+      "\n"
+      "/**\n"
+      " * Static version of the {@see toObject} method.\n"
+      " * @param {boolean|undefined} includeInstance Whether to include the "
+      "JSPB\n"
+      " *     instance for transitional soy proto support:\n"
+      " *     http://goto/soy-param-migration\n"
+      " * @param {!$classname$} msg The msg instance to transform.\n"
+      " * @return {!Object}\n"
+      " */\n"
+      "$classname$.toObject = function(includeInstance, msg) {\n"
+      "  var f, obj = {",
+      "classname", GetPath(options, desc));
+
+  bool first = true;
+  for (int i = 0; i < desc->field_count(); i++) {
+    const FieldDescriptor* field = desc->field(i);
+    if (IgnoreField(field)) {
+      continue;
+    }
+
+    if (!first) {
+      printer->Print(",\n    ");
+    } else {
+      printer->Print("\n    ");
+      first = false;
+    }
+
+    GenerateClassFieldToObject(options, printer, field);
+  }
+
+  if (!first) {
+    printer->Print("\n  };\n\n");
+  } else {
+    printer->Print("\n\n  };\n\n");
+  }
+
+  if (IsExtendable(desc)) {
+    printer->Print(
+        "  jspb.Message.toObjectExtension(/** @type {!jspb.Message} */ (msg), "
+        "obj,\n"
+        "      $extObject$, $class$.prototype.getExtension,\n"
+        "      includeInstance);\n",
+        "extObject", JSExtensionsObjectName(options, desc),
+        "class", GetPath(options, desc));
+  }
+
+  printer->Print(
+      "  if (includeInstance) {\n"
+      "    obj.$$jspbMessageInstance = msg\n"
+      "  }\n"
+      "  return obj;\n"
+      "};\n"
+      "}\n"
+      "\n"
+      "\n",
+      "classname", GetPath(options, desc));
+}
+
+void Generator::GenerateClassFieldToObject(const GeneratorOptions& options,
+                                           io::Printer* printer,
+                                           const FieldDescriptor* field) const {
+  printer->Print("$fieldname$: ",
+                 "fieldname", JSObjectFieldName(field));
+
+  if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+    // Message field.
+    if (field->is_repeated()) {
+      {
+        printer->Print("jspb.Message.toObjectList(msg.get$getter$(),\n"
+                       "    $type$.toObject, includeInstance)",
+                       "getter", JSGetterName(field),
+                       "type", GetPath(options, field->message_type()));
+      }
+    } else {
+      printer->Print("(f = msg.get$getter$()) && "
+                     "$type$.toObject(includeInstance, f)",
+                     "getter", JSGetterName(field),
+                     "type", GetPath(options, field->message_type()));
+    }
+  } else {
+    // Simple field (singular or repeated).
+    if (!HasFieldPresence(field) && !field->is_repeated()) {
+      // Delegate to the generated get<field>() method in order not to duplicate
+      // the proto3-field-default-value logic here.
+      printer->Print("msg.get$getter$()",
+                     "getter", JSGetterName(field));
+    } else {
+      if (field->has_default_value()) {
+        printer->Print("jspb.Message.getField(msg, $index$) != null ? "
+                       "jspb.Message.getField(msg, $index$) : $defaultValue$",
+                       "index", JSFieldIndex(field),
+                       "defaultValue", JSFieldDefault(field));
+      } else {
+        printer->Print("jspb.Message.getField(msg, $index$)",
+                       "index", JSFieldIndex(field));
+      }
+    }
+  }
+}
+
+void Generator::GenerateClassFromObject(const GeneratorOptions& options,
+                                        io::Printer* printer,
+                                        const Descriptor* desc) const {
+  printer->Print(
+      "if (jspb.Message.GENERATE_FROM_OBJECT) {\n"
+      "/**\n"
+      " * Loads data from an object into a new instance of this proto.\n"
+      " * @param {!Object} obj The object representation of this proto to\n"
+      " *     load the data from.\n"
+      " * @return {!$classname$}\n"
+      " */\n"
+      "$classname$.fromObject = function(obj) {\n"
+      "  var f, msg = new $classname$();\n",
+      "classname", GetPath(options, desc));
+
+  for (int i = 0; i < desc->field_count(); i++) {
+    const FieldDescriptor* field = desc->field(i);
+    GenerateClassFieldFromObject(options, printer, field);
+  }
+
+  printer->Print(
+      "  return msg;\n"
+      "};\n"
+      "}\n");
+}
+
+void Generator::GenerateClassFieldFromObject(
+    const GeneratorOptions& options,
+    io::Printer* printer,
+    const FieldDescriptor* field) const {
+  if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+    // Message field (singular or repeated)
+    if (field->is_repeated()) {
+      {
+        printer->Print(
+            "  goog.isDef(obj.$name$) && "
+            "jspb.Message.setRepeatedWrapperField(\n"
+            "      msg, $index$, goog.array.map(obj.$name$, function(i) {\n"
+            "        return $fieldclass$.fromObject(i);\n"
+            "      }));\n",
+            "name", JSObjectFieldName(field),
+            "index", JSFieldIndex(field),
+            "fieldclass", GetPath(options, field->message_type()));
+      }
+    } else {
+      printer->Print(
+          "  goog.isDef(obj.$name$) && jspb.Message.setWrapperField(\n"
+          "      msg, $index$, $fieldclass$.fromObject(obj.$name$));\n",
+          "name", JSObjectFieldName(field),
+          "index", JSFieldIndex(field),
+          "fieldclass", GetPath(options, field->message_type()));
+    }
+  } else {
+    // Simple (primitive) field.
+    printer->Print(
+        "  goog.isDef(obj.$name$) && jspb.Message.setField(msg, $index$, "
+        "obj.$name$);\n",
+        "name", JSObjectFieldName(field),
+        "index", JSFieldIndex(field));
+  }
+}
+
+void Generator::GenerateClassClone(const GeneratorOptions& options,
+                                   io::Printer* printer,
+                                   const Descriptor* desc) const {
+  printer->Print(
+      "/**\n"
+      " * Creates a deep clone of this proto. No data is shared with the "
+      "original.\n"
+      " * @return {!$name$} The clone.\n"
+      " */\n"
+      "$name$.prototype.cloneMessage = function() {\n"
+      "  return /** @type {!$name$} */ (jspb.Message.cloneMessage(this));\n"
+      "};\n\n\n",
+      "name", GetPath(options, desc));
+}
+
+void Generator::GenerateClassRegistration(const GeneratorOptions& options,
+                                          io::Printer* printer,
+                                          const Descriptor* desc) const {
+  // Register any extensions defined inside this message type.
+  for (int i = 0; i < desc->extension_count(); i++) {
+    const FieldDescriptor* extension = desc->extension(i);
+    if (ShouldGenerateExtension(extension)) {
+      GenerateExtension(options, printer, extension);
+    }
+  }
+
+}
+
+void Generator::GenerateClassFields(const GeneratorOptions& options,
+                                    io::Printer* printer,
+                                    const Descriptor* desc) const {
+  for (int i = 0; i < desc->field_count(); i++) {
+    if (!IgnoreField(desc->field(i))) {
+      GenerateClassField(options, printer, desc->field(i));
+    }
+  }
+}
+
+void Generator::GenerateClassField(const GeneratorOptions& options,
+                                   io::Printer* printer,
+                                   const FieldDescriptor* field) const {
+  if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+    printer->Print(
+        "/**\n"
+        " * $fielddef$\n"
+        "$comment$"
+        " * @return {$type$}\n"
+        " */\n",
+        "fielddef", FieldDefinition(options, field),
+        "comment", FieldComments(field),
+        "type", JSFieldTypeAnnotation(options, field,
+                                      /* force_optional = */ false,
+                                      /* force_present = */ false,
+                                      /* singular_if_not_packed = */ false,
+                                      /* always_singular = */ false));
+    printer->Print(
+        "$class$.prototype.get$name$ = function() {\n"
+        "  return /** @type{$type$} */ (\n"
+        "    jspb.Message.get$rpt$WrapperField(this, $wrapperclass$, "
+        "$index$$required$));\n"
+        "};\n"
+        "\n"
+        "\n",
+        "class", GetPath(options, field->containing_type()),
+        "name", JSGetterName(field),
+        "type", JSFieldTypeAnnotation(options, field,
+                                      /* force_optional = */ false,
+                                      /* force_present = */ false,
+                                      /* singular_if_not_packed = */ false,
+                                      /* always_singular = */ false),
+        "rpt", (field->is_repeated() ? "Repeated" : ""),
+        "index", JSFieldIndex(field),
+        "wrapperclass", GetPath(options, field->message_type()),
+        "required", (field->label() == FieldDescriptor::LABEL_REQUIRED ?
+                     ", 1" : ""));
+    printer->Print(
+        "/** @param {$optionaltype$} value $returndoc$ */\n"
+        "$class$.prototype.set$name$ = function(value) {\n"
+        "  jspb.Message.set$oneoftag$$repeatedtag$WrapperField(",
+        "optionaltype",
+        JSFieldTypeAnnotation(options, field,
+                              /* force_optional = */ true,
+                              /* force_present = */ false,
+                              /* singular_if_not_packed = */ false,
+                              /* always_singular = */ false),
+        "returndoc", JSReturnDoc(options, field),
+        "class", GetPath(options, field->containing_type()),
+        "name", JSGetterName(field),
+        "oneoftag", (field->containing_oneof() ? "Oneof" : ""),
+        "repeatedtag", (field->is_repeated() ? "Repeated" : ""));
+
+    printer->Print(
+        "this, $index$$oneofgroup$, value);$returnvalue$\n"
+        "};\n"
+        "\n"
+        "\n",
+        "index", JSFieldIndex(field),
+        "oneofgroup", (field->containing_oneof() ?
+                       (", " + JSOneofArray(options, field)) : ""),
+        "returnvalue", JSReturnClause(field));
+
+    printer->Print(
+        "$class$.prototype.clear$name$ = function() {\n"
+        "  this.set$name$($clearedvalue$);$returnvalue$\n"
+        "};\n"
+        "\n"
+        "\n",
+        "class", GetPath(options, field->containing_type()),
+        "name", JSGetterName(field),
+        "clearedvalue", (field->is_repeated() ? "[]" : "undefined"),
+        "returnvalue", JSReturnClause(field));
+
+  } else {
+    string typed_annotation;
+
+    // Simple (primitive) field, either singular or repeated.
+    {
+      typed_annotation = JSFieldTypeAnnotation(options, field,
+                              /* force_optional = */ false,
+                              /* force_present = */ !HasFieldPresence(field),
+                              /* singular_if_not_packed = */ false,
+                              /* always_singular = */ false),
+      printer->Print(
+          "/**\n"
+          " * $fielddef$\n"
+          "$comment$"
+          " * @return {$type$}\n"
+          " */\n",
+          "fielddef", FieldDefinition(options, field),
+          "comment", FieldComments(field),
+          "type", typed_annotation);
+    }
+
+    printer->Print(
+        "$class$.prototype.get$name$ = function() {\n",
+        "class", GetPath(options, field->containing_type()),
+        "name", JSGetterName(field));
+
+    {
+      printer->Print(
+          "  return /** @type {$type$} */ (",
+          "type", typed_annotation);
+    }
+
+    // For proto3 fields without presence, use special getters that will return
+    // defaults when the field is unset, possibly constructing a value if
+    // required.
+    if (!HasFieldPresence(field) && !field->is_repeated()) {
+      printer->Print("jspb.Message.getFieldProto3(this, $index$, $default$)",
+                     "index", JSFieldIndex(field),
+                     "default", Proto3PrimitiveFieldDefault(field));
+    } else {
+      if (field->has_default_value()) {
+        printer->Print("jspb.Message.getField(this, $index$) != null ? "
+                       "jspb.Message.getField(this, $index$) : $defaultValue$",
+                       "index", JSFieldIndex(field),
+                       "defaultValue", JSFieldDefault(field));
+      } else {
+        printer->Print("jspb.Message.getField(this, $index$)",
+                       "index", JSFieldIndex(field));
+      }
+    }
+
+    {
+      printer->Print(
+          ");\n"
+          "};\n"
+          "\n"
+          "\n");
+    }
+
+    {
+      printer->Print(
+          "/** @param {$optionaltype$} value $returndoc$ */\n",
+          "optionaltype",
+          JSFieldTypeAnnotation(options, field,
+                                /* force_optional = */ true,
+                                /* force_present = */ !HasFieldPresence(field),
+                                /* singular_if_not_packed = */ false,
+                                /* always_singular = */ false),
+          "returndoc", JSReturnDoc(options, field));
+    }
+
+    printer->Print(
+        "$class$.prototype.set$name$ = function(value) {\n"
+        "  jspb.Message.set$oneoftag$Field(this, $index$",
+        "class", GetPath(options, field->containing_type()),
+        "name", JSGetterName(field),
+        "oneoftag", (field->containing_oneof() ? "Oneof" : ""),
+        "index", JSFieldIndex(field));
+    printer->Print(
+        "$oneofgroup$, $type$value$rptvalueinit$$typeclose$);$returnvalue$\n"
+        "};\n"
+        "\n"
+        "\n",
+        "type", "",
+        "typeclose", "",
+        "oneofgroup",
+        (field->containing_oneof() ? (", " + JSOneofArray(options, field))
+                                   : ""),
+        "returnvalue", JSReturnClause(field), "rptvalueinit",
+        (field->is_repeated() ? " || []" : ""));
+
+
+    if (HasFieldPresence(field)) {
+      printer->Print(
+          "$class$.prototype.clear$name$ = function() {\n"
+          "  jspb.Message.set$oneoftag$Field(this, $index$$oneofgroup$, ",
+          "class", GetPath(options, field->containing_type()),
+          "name", JSGetterName(field),
+          "oneoftag", (field->containing_oneof() ? "Oneof" : ""),
+          "oneofgroup", (field->containing_oneof() ?
+                         (", " + JSOneofArray(options, field)) : ""),
+          "index", JSFieldIndex(field));
+      printer->Print(
+          "$clearedvalue$);$returnvalue$\n"
+          "};\n"
+          "\n"
+          "\n",
+          "clearedvalue", (field->is_repeated() ? "[]" : "undefined"),
+          "returnvalue", JSReturnClause(field));
+    }
+  }
+}
+
+void Generator::GenerateClassExtensionFieldInfo(const GeneratorOptions& options,
+                                                io::Printer* printer,
+                                                const Descriptor* desc) const {
+  if (IsExtendable(desc)) {
+    printer->Print(
+        "\n"
+        "/**\n"
+        " * The extensions registered with this message class. This is a "
+        "map of\n"
+        " * extension field number to fieldInfo object.\n"
+        " *\n"
+        " * For example:\n"
+        " *     { 123: {fieldIndex: 123, fieldName: {my_field_name: 0}, "
+        "ctor: proto.example.MyMessage} }\n"
+        " *\n"
+        " * fieldName contains the JsCompiler renamed field name property "
+        "so that it\n"
+        " * works in OPTIMIZED mode.\n"
+        " *\n"
+        " * @type {!Object.<number, jspb.ExtensionFieldInfo>}\n"
+        " */\n"
+        "$class$.extensions = {};\n"
+        "\n",
+        "class", GetPath(options, desc));
+  }
+}
+
+
+void Generator::GenerateClassDeserializeBinary(const GeneratorOptions& options,
+                                               io::Printer* printer,
+                                               const Descriptor* desc) const {
+  // TODO(cfallin): Handle lazy decoding when requested by field option and/or
+  // by default for 'bytes' fields and packed repeated fields.
+
+  printer->Print(
+      "/**\n"
+      " * Deserializes binary data (in protobuf wire format).\n"
+      " * @param {jspb.ByteSource} bytes The bytes to deserialize.\n"
+      " * @return {!$class$}\n"
+      " */\n"
+      "$class$.deserializeBinary = function(bytes) {\n"
+      "  var reader = new jspb.BinaryReader(bytes);\n"
+      "  var msg = new $class$;\n"
+      "  return $class$.deserializeBinaryFromReader(msg, reader);\n"
+      "};\n"
+      "\n"
+      "\n"
+      "/**\n"
+      " * Deserializes binary data (in protobuf wire format) from the\n"
+      " * given reader into the given message object.\n"
+      " * @param {!$class$} msg The message object to deserialize into.\n"
+      " * @param {!jspb.BinaryReader} reader The BinaryReader to use.\n"
+      " * @return {!$class$}\n"
+      " */\n"
+      "$class$.deserializeBinaryFromReader = function(msg, reader) {\n"
+      "  while (reader.nextField()) {\n"
+      "    if (reader.isEndGroup()) {\n"
+      "      break;\n"
+      "    }\n"
+      "    var field = reader.getFieldNumber();\n"
+      "    switch (field) {\n",
+      "class", GetPath(options, desc));
+
+  for (int i = 0; i < desc->field_count(); i++) {
+    GenerateClassDeserializeBinaryField(options, printer, desc->field(i));
+  }
+
+  printer->Print(
+      "    default:\n");
+  if (IsExtendable(desc)) {
+    printer->Print(
+        "      jspb.Message.readBinaryExtension(msg, reader, $extobj$,\n"
+        "        $class$.prototype.getExtension,\n"
+        "        $class$.prototype.setExtension);\n"
+        "      break;\n",
+        "extobj", JSExtensionsObjectName(options, desc),
+        "class", GetPath(options, desc));
+  } else {
+    printer->Print(
+        "      reader.skipField();\n"
+        "      break;\n");
+  }
+
+  printer->Print(
+      "    }\n"
+      "  }\n"
+      "  return msg;\n"
+      "};\n"
+      "\n"
+      "\n");
+}
+
+void Generator::GenerateClassDeserializeBinaryField(
+    const GeneratorOptions& options,
+    io::Printer* printer,
+    const FieldDescriptor* field) const {
+
+  printer->Print("    case $num$:\n",
+                 "num", SimpleItoa(field->number()));
+
+  if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+    printer->Print(
+        "      var value = new $fieldclass$;\n"
+        "      reader.read$msgOrGroup$($grpfield$value,"
+        "$fieldclass$.deserializeBinaryFromReader);\n",
+        "fieldclass", GetPath(options, field->message_type()),
+        "msgOrGroup", (field->type() == FieldDescriptor::TYPE_GROUP) ?
+                      "Group" : "Message",
+        "grpfield", (field->type() == FieldDescriptor::TYPE_GROUP) ?
+                    (SimpleItoa(field->number()) + ", ") : "");
+  } else {
+    printer->Print(
+        "      var value = /** @type {$fieldtype$} */ (reader.$reader$());\n",
+        "fieldtype", JSFieldTypeAnnotation(options, field, false, true,
+                                           /* singular_if_not_packed = */ true,
+                                           /* always_singular = */ false),
+        "reader", JSBinaryReaderMethodName(field));
+  }
+
+  if (field->is_repeated() && !field->is_packed()) {
+    // Repeated fields receive a |value| one at at a time; append to array
+    // returned by get$name$().
+    printer->Print(
+        "      msg.get$name$().push(value);\n",
+        "name", JSGetterName(field));
+  } else {
+    // Singular fields, and packed repeated fields, receive a |value| either as
+    // the field's value or as the array of all the field's values; set this as
+    // the field's value directly.
+    printer->Print(
+        "      msg.set$name$(value);\n",
+        "name", JSGetterName(field));
+  }
+
+  printer->Print("      break;\n");
+}
+
+void Generator::GenerateClassSerializeBinary(const GeneratorOptions& options,
+                                             io::Printer* printer,
+                                             const Descriptor* desc) const {
+  printer->Print(
+      "/**\n"
+      " * Class method variant: serializes the given message to binary data\n"
+      " * (in protobuf wire format), writing to the given BinaryWriter.\n"
+      " * @param {!$class$} message\n"
+      " * @param {!jspb.BinaryWriter} writer\n"
+      " */\n"
+      "$class$.serializeBinaryToWriter = function(message, "
+      "writer) {\n"
+      "  message.serializeBinaryToWriter(writer);\n"
+      "};\n"
+      "\n"
+      "\n"
+      "/**\n"
+      " * Serializes the message to binary data (in protobuf wire format).\n"
+      " * @return {!Uint8Array}\n"
+      " */\n"
+      "$class$.prototype.serializeBinary = function() {\n"
+      "  var writer = new jspb.BinaryWriter();\n"
+      "  this.serializeBinaryToWriter(writer);\n"
+      "  return writer.getResultBuffer();\n"
+      "};\n"
+      "\n"
+      "\n"
+      "/**\n"
+      " * Serializes the message to binary data (in protobuf wire format),\n"
+      " * writing to the given BinaryWriter.\n"
+      " * @param {!jspb.BinaryWriter} writer\n"
+      " */\n"
+      "$class$.prototype.serializeBinaryToWriter = function (writer) {\n"
+      "  var f = undefined;\n",
+      "class", GetPath(options, desc));
+
+  for (int i = 0; i < desc->field_count(); i++) {
+    GenerateClassSerializeBinaryField(options, printer, desc->field(i));
+  }
+
+  if (IsExtendable(desc)) {
+    printer->Print(
+        "  jspb.Message.serializeBinaryExtensions(this, writer, $extobj$,\n"
+        "    $class$.prototype.getExtension);\n",
+        "extobj", JSExtensionsObjectName(options, desc),
+        "class", GetPath(options, desc));
+  }
+
+  printer->Print(
+      "};\n"
+      "\n"
+      "\n");
+}
+
+void Generator::GenerateClassSerializeBinaryField(
+    const GeneratorOptions& options,
+    io::Printer* printer,
+    const FieldDescriptor* field) const {
+  printer->Print(
+      "  f = this.get$name$();\n",
+      "name", JSGetterName(field));
+
+  if (field->is_repeated()) {
+    printer->Print(
+        "  if (f.length > 0) {\n");
+  } else {
+    if (HasFieldPresence(field)) {
+      printer->Print(
+          "  if (f != null) {\n");
+    } else {
+      // No field presence: serialize onto the wire only if value is
+      // non-default.  Defaults are documented here:
+      // https://goto.google.com/lhdfm
+      switch (field->cpp_type()) {
+        case FieldDescriptor::CPPTYPE_INT32:
+        case FieldDescriptor::CPPTYPE_INT64:
+        case FieldDescriptor::CPPTYPE_UINT32:
+        case FieldDescriptor::CPPTYPE_UINT64: {
+          {
+            printer->Print("  if (f !== 0) {\n");
+          }
+          break;
+        }
+
+        case FieldDescriptor::CPPTYPE_ENUM:
+        case FieldDescriptor::CPPTYPE_FLOAT:
+        case FieldDescriptor::CPPTYPE_DOUBLE:
+          printer->Print(
+              "  if (f !== 0.0) {\n");
+          break;
+        case FieldDescriptor::CPPTYPE_BOOL:
+          printer->Print(
+              "  if (f) {\n");
+          break;
+        case FieldDescriptor::CPPTYPE_STRING:
+          printer->Print(
+              "  if (f.length > 0) {\n");
+          break;
+        default:
+          assert(false);
+          break;
+      }
+    }
+  }
+
+  printer->Print(
+      "    writer.$writer$(\n"
+      "      $index$,\n"
+      "      f",
+      "writer", JSBinaryWriterMethodName(field),
+      "name", JSGetterName(field),
+      "index", SimpleItoa(field->number()));
+
+  if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
+    printer->Print(
+        ",\n"
+        "      $submsg$.serializeBinaryToWriter\n",
+        "submsg", GetPath(options, field->message_type()));
+  } else {
+    printer->Print("\n");
+  }
+  printer->Print(
+      "    );\n"
+      "  }\n");
+}
+
+void Generator::GenerateEnum(const GeneratorOptions& options,
+                             io::Printer* printer,
+                             const EnumDescriptor* enumdesc) const {
+  printer->Print(
+      "/**\n"
+      " * @enum {number}\n"
+      " */\n"
+      "$name$ = {\n",
+      "name", GetPath(options, enumdesc));
+
+  for (int i = 0; i < enumdesc->value_count(); i++) {
+    const EnumValueDescriptor* value = enumdesc->value(i);
+    printer->Print(
+        "  $name$: $value$$comma$\n",
+        "name", ToEnumCase(value->name()),
+        "value", SimpleItoa(value->number()),
+        "comma", (i == enumdesc->value_count() - 1) ? "" : ",");
+  }
+
+  printer->Print(
+      "};\n"
+      "\n");
+}
+
+void Generator::GenerateExtension(const GeneratorOptions& options,
+                                  io::Printer* printer,
+                                  const FieldDescriptor* field) const {
+  string extension_scope =
+      (field->extension_scope() ?
+       GetPath(options, field->extension_scope()) :
+       GetPath(options, field->file()));
+
+  printer->Print(
+      "\n"
+      "/**\n"
+      " * A tuple of {field number, class constructor} for the extension\n"
+      " * field named `$name$`.\n"
+      " * @type {!jspb.ExtensionFieldInfo.<$extensionType$>}\n"
+      " */\n"
+      "$class$.$name$ = new jspb.ExtensionFieldInfo(\n",
+      "name", JSObjectFieldName(field),
+      "class", extension_scope,
+      "extensionType", JSFieldTypeAnnotation(
+          options, field,
+          /* force_optional = */ false,
+          /* force_present = */ true,
+          /* singular_if_not_packed = */ false,
+          /* always_singular = */ false));
+  printer->Print(
+      "    $index$,\n"
+      "    {$name$: 0},\n"
+      "    $ctor$,\n"
+      "     /** @type {?function((boolean|undefined),!jspb.Message=): "
+      "!Object} */ (\n"
+      "         $toObject$),\n"
+      "    $repeated$",
+      "index", SimpleItoa(field->number()),
+      "name", JSObjectFieldName(field),
+      "ctor", (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE ?
+               GetPath(options, field->message_type()) : string("null")),
+      "toObject", (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE ?
+                   (GetPath(options, field->message_type()) + ".toObject") :
+                   string("null")),
+      "repeated", (field->is_repeated() ? "1" : "0"));
+
+  if (options.binary) {
+    printer->Print(
+        ",\n"
+        "    jspb.BinaryReader.prototype.$binaryReaderFn$,\n"
+        "    jspb.BinaryWriter.prototype.$binaryWriterFn$,\n"
+        "    $binaryMessageSerializeFn$,\n"
+        "    $binaryMessageDeserializeFn$,\n"
+        "    $isPacked$);\n",
+        "binaryReaderFn", JSBinaryReaderMethodName(field),
+        "binaryWriterFn", JSBinaryWriterMethodName(field),
+        "binaryMessageSerializeFn",
+        (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) ?
+        (GetPath(options, field->message_type()) +
+         ".serializeBinaryToWriter") : "null",
+        "binaryMessageDeserializeFn",
+        (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) ?
+        (GetPath(options, field->message_type()) +
+         ".deserializeBinaryFromReader") : "null",
+        "isPacked", (field->is_packed() ? "true" : "false"));
+  } else {
+    printer->Print(");\n");
+  }
+
+  printer->Print(
+      "// This registers the extension field with the extended class, so that\n"
+      "// toObject() will function correctly.\n"
+      "$extendName$[$index$] = $class$.$name$;\n"
+      "\n",
+      "extendName", JSExtensionsObjectName(options, field->containing_type()),
+      "index", SimpleItoa(field->number()),
+      "class", extension_scope,
+      "name", JSObjectFieldName(field));
+}
+
+bool GeneratorOptions::ParseFromOptions(
+    const vector< pair< string, string > >& options,
+    string* error) {
+  for (int i = 0; i < options.size(); i++) {
+    if (options[i].first == "add_require_for_enums") {
+      if (options[i].second != "") {
+        *error = "Unexpected option value for add_require_for_enums";
+        return false;
+      }
+      add_require_for_enums = true;
+    } else if (options[i].first == "binary") {
+      if (options[i].second != "") {
+        *error = "Unexpected option value for binary";
+        return false;
+      }
+      binary = true;
+    } else if (options[i].first == "testonly") {
+      if (options[i].second != "") {
+        *error = "Unexpected option value for testonly";
+        return false;
+      }
+      testonly = true;
+    } else if (options[i].first == "error_on_name_conflict") {
+      if (options[i].second != "") {
+        *error = "Unexpected option value for error_on_name_conflict";
+        return false;
+      }
+      error_on_name_conflict = true;
+    } else if (options[i].first == "output_dir") {
+      output_dir = options[i].second;
+    } else if (options[i].first == "namespace_prefix") {
+      namespace_prefix = options[i].second;
+    } else if (options[i].first == "library") {
+      library = options[i].second;
+    } else {
+      // Assume any other option is an output directory, as long as it is a bare
+      // `key` rather than a `key=value` option.
+      if (options[i].second != "") {
+        *error = "Unknown option: " + options[i].first;
+        return false;
+      }
+      output_dir = options[i].first;
+    }
+  }
+
+  return true;
+}
+
+void Generator::GenerateFilesInDepOrder(
+    const GeneratorOptions& options,
+    io::Printer* printer,
+    const vector<const FileDescriptor*>& files) const {
+  // Build a std::set over all files so that the DFS can detect when it recurses
+  // into a dep not specified in the user's command line.
+  std::set<const FileDescriptor*> all_files(files.begin(), files.end());
+  // Track the in-progress set of files that have been generated already.
+  std::set<const FileDescriptor*> generated;
+  for (int i = 0; i < files.size(); i++) {
+    GenerateFileAndDeps(options, printer, files[i], &all_files, &generated);
+  }
+}
+
+void Generator::GenerateFileAndDeps(
+    const GeneratorOptions& options,
+    io::Printer* printer,
+    const FileDescriptor* root,
+    std::set<const FileDescriptor*>* all_files,
+    std::set<const FileDescriptor*>* generated) const {
+  // Skip if already generated.
+  if (generated->find(root) != generated->end()) {
+    return;
+  }
+  generated->insert(root);
+
+  // Generate all dependencies before this file's content.
+  for (int i = 0; i < root->dependency_count(); i++) {
+    const FileDescriptor* dep = root->dependency(i);
+    GenerateFileAndDeps(options, printer, dep, all_files, generated);
+  }
+
+  // Generate this file's content.  Only generate if the file is part of the
+  // original set requested to be generated; i.e., don't take all transitive
+  // deps down to the roots.
+  if (all_files->find(root) != all_files->end()) {
+    GenerateClassesAndEnums(options, printer, root);
+  }
+}
+
+bool Generator::GenerateAll(const vector<const FileDescriptor*>& files,
+                            const string& parameter,
+                            GeneratorContext* context,
+                            string* error) const {
+  vector< pair< string, string > > option_pairs;
+  ParseGeneratorParameter(parameter, &option_pairs);
+  GeneratorOptions options;
+  if (!options.ParseFromOptions(option_pairs, error)) {
+    return false;
+  }
+
+
+  // We're either generating a single library file with definitions for message
+  // and enum types in *all* FileDescriptor inputs, or we're generating a single
+  // file for each type.
+  if (options.library != "") {
+    string filename = options.output_dir + "/" + options.library + ".js";
+    google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> output(context->Open(filename));
+    GOOGLE_CHECK(output.get());
+    io::Printer printer(output.get(), '$');
+
+    // Pull out all extensions -- we need these to generate all
+    // provides/requires.
+    vector<const FieldDescriptor*> extensions;
+    for (int i = 0; i < files.size(); i++) {
+      for (int j = 0; j < files[i]->extension_count(); j++) {
+        const FieldDescriptor* extension = files[i]->extension(j);
+        extensions.push_back(extension);
+      }
+    }
+
+    GenerateHeader(options, &printer);
+
+    std::set<string> provided;
+    FindProvides(options, &printer, files, &provided);
+    FindProvidesForFields(options, &printer, extensions, &provided);
+    GenerateProvides(options, &printer, &provided);
+    GenerateTestOnly(options, &printer);
+    GenerateRequires(options, &printer, files, &provided);
+
+    GenerateFilesInDepOrder(options, &printer, files);
+
+    for (int i = 0; i < extensions.size(); i++) {
+      if (ShouldGenerateExtension(extensions[i])) {
+        GenerateExtension(options, &printer, extensions[i]);
+      }
+    }
+
+    if (printer.failed()) {
+      return false;
+    }
+  } else {
+    // Collect all types, and print each type to a separate file. Pull out
+    // free-floating extensions while we make this pass.
+    map< string, vector<const FieldDescriptor*> > extensions_by_namespace;
+
+    // If we're generating code in file-per-type mode, avoid overwriting files
+    // by choosing the last descriptor that writes each filename and permitting
+    // only those to generate code.
+
+    // Current descriptor that will generate each filename, indexed by filename.
+    map<string, const void*> desc_by_filename;
+    // Set of descriptors allowed to generate files.
+    set<const void*> allowed_descs;
+
+    for (int i = 0; i < files.size(); i++) {
+      // Collect all (descriptor, filename) pairs.
+      map<const void*, string> descs_in_file;
+      for (int j = 0; j < files[i]->message_type_count(); j++) {
+        const Descriptor* desc = files[i]->message_type(j);
+        string filename =
+            options.output_dir + "/" + ToFileName(desc->name()) + ".js";
+        descs_in_file[desc] = filename;
+      }
+      for (int j = 0; j < files[i]->enum_type_count(); j++) {
+        const EnumDescriptor* desc = files[i]->enum_type(j);
+        string filename =
+            options.output_dir + "/" + ToFileName(desc->name()) + ".js";
+        descs_in_file[desc] = filename;
+      }
+
+      // For each (descriptor, filename) pair, update the
+      // descriptors-by-filename map, and if a previous descriptor was already
+      // writing the filename, remove it from the allowed-descriptors set.
+      map<const void*, string>::iterator it;
+      for (it = descs_in_file.begin(); it != descs_in_file.end(); ++it) {
+        const void* desc = it->first;
+        const string& filename = it->second;
+        if (desc_by_filename.find(filename) != desc_by_filename.end()) {
+          if (options.error_on_name_conflict) {
+            *error = "Name conflict: file name " + filename +
+                     " would be generated by two descriptors";
+            return false;
+          }
+          allowed_descs.erase(desc_by_filename[filename]);
+        }
+        desc_by_filename[filename] = desc;
+        allowed_descs.insert(desc);
+      }
+    }
+
+    // Generate code.
+    for (int i = 0; i < files.size(); i++) {
+      const FileDescriptor* file = files[i];
+      for (int j = 0; j < file->message_type_count(); j++) {
+        const Descriptor* desc = file->message_type(j);
+        if (allowed_descs.find(desc) == allowed_descs.end()) {
+          continue;
+        }
+
+        string filename = options.output_dir + "/" +
+            ToFileName(desc->name()) + ".js";
+        google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> output(
+            context->Open(filename));
+        GOOGLE_CHECK(output.get());
+        io::Printer printer(output.get(), '$');
+
+        GenerateHeader(options, &printer);
+
+        std::set<string> provided;
+        FindProvidesForMessage(options, &printer, desc, &provided);
+        GenerateProvides(options, &printer, &provided);
+        GenerateTestOnly(options, &printer);
+        GenerateRequires(options, &printer, desc, &provided);
+
+        GenerateClass(options, &printer, desc);
+
+        if (printer.failed()) {
+          return false;
+        }
+      }
+      for (int j = 0; j < file->enum_type_count(); j++) {
+        const EnumDescriptor* enumdesc = file->enum_type(j);
+        if (allowed_descs.find(enumdesc) == allowed_descs.end()) {
+          continue;
+        }
+
+        string filename = options.output_dir + "/" +
+            ToFileName(enumdesc->name()) + ".js";
+
+        google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> output(
+            context->Open(filename));
+        GOOGLE_CHECK(output.get());
+        io::Printer printer(output.get(), '$');
+
+        GenerateHeader(options, &printer);
+
+        std::set<string> provided;
+        FindProvidesForEnum(options, &printer, enumdesc, &provided);
+        GenerateProvides(options, &printer, &provided);
+        GenerateTestOnly(options, &printer);
+
+        GenerateEnum(options, &printer, enumdesc);
+
+        if (printer.failed()) {
+          return false;
+        }
+      }
+      // Pull out all free-floating extensions and generate files for those too.
+      for (int j = 0; j < file->extension_count(); j++) {
+        const FieldDescriptor* extension = file->extension(j);
+        extensions_by_namespace[GetPath(options, files[i])]
+            .push_back(extension);
+      }
+    }
+
+    // Generate extensions in separate files.
+    map< string, vector<const FieldDescriptor*> >::iterator it;
+    for (it = extensions_by_namespace.begin();
+         it != extensions_by_namespace.end();
+         ++it) {
+      string filename = options.output_dir + "/" +
+          ToFileName(it->first) + ".js";
+
+      google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> output(
+          context->Open(filename));
+      GOOGLE_CHECK(output.get());
+      io::Printer printer(output.get(), '$');
+
+      GenerateHeader(options, &printer);
+
+      std::set<string> provided;
+      FindProvidesForFields(options, &printer, it->second, &provided);
+      GenerateProvides(options, &printer, &provided);
+      GenerateTestOnly(options, &printer);
+      GenerateRequires(options, &printer, it->second, &provided);
+
+      for (int j = 0; j < it->second.size(); j++) {
+        if (ShouldGenerateExtension(it->second[j])) {
+          GenerateExtension(options, &printer, it->second[j]);
+        }
+      }
+    }
+  }
+
+  return true;
+}
+
+}  // namespace js
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/compiler/js/js_generator.h b/src/google/protobuf/compiler/js/js_generator.h
new file mode 100755
index 00000000..db2dceb3
--- /dev/null
+++ b/src/google/protobuf/compiler/js/js_generator.h
@@ -0,0 +1,265 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef GOOGLE_PROTOBUF_COMPILER_JS_GENERATOR_H__
+#define GOOGLE_PROTOBUF_COMPILER_JS_GENERATOR_H__
+
+#include <string>
+#include <set>
+
+#include <google/protobuf/compiler/code_generator.h>
+
+namespace google {
+namespace protobuf {
+
+class Descriptor;
+class EnumDescriptor;
+class FieldDescriptor;
+class OneofDescriptor;
+class FileDescriptor;
+
+namespace io { class Printer; }
+
+namespace compiler {
+namespace js {
+
+struct GeneratorOptions {
+  // Add a `goog.requires()` call for each enum type used. If not set, a forward
+  // declaration with `goog.forwardDeclare` is produced instead.
+  bool add_require_for_enums;
+  // Set this as a test-only module via `goog.setTestOnly();`.
+  bool testonly;
+  // Output path.
+  string output_dir;
+  // Namespace prefix.
+  string namespace_prefix;
+  // Create a library with name <name>_lib.js rather than a separate .js file
+  // per type?
+  string library;
+  // Error if there are two types that would generate the same output file?
+  bool error_on_name_conflict;
+  // Enable binary-format support?
+  bool binary;
+
+  GeneratorOptions()
+      : add_require_for_enums(false),
+        testonly(false),
+        output_dir("."),
+        namespace_prefix(""),
+        library(""),
+        error_on_name_conflict(false),
+        binary(false) {}
+
+  bool ParseFromOptions(
+      const vector< pair< string, string > >& options,
+      string* error);
+};
+
+class LIBPROTOC_EXPORT Generator : public CodeGenerator {
+ public:
+  Generator() {}
+  virtual ~Generator() {}
+
+  virtual bool Generate(const FileDescriptor* file,
+                        const string& parameter,
+                        GeneratorContext* context,
+                        string* error) const {
+    *error = "Unimplemented Generate() method. Call GenerateAll() instead.";
+    return false;
+  }
+
+  virtual bool HasGenerateAll() const { return true; }
+
+  virtual bool GenerateAll(const vector<const FileDescriptor*>& files,
+                           const string& parameter,
+                           GeneratorContext* context,
+                           string* error) const;
+
+ private:
+  void GenerateHeader(const GeneratorOptions& options,
+                      io::Printer* printer) const;
+
+  // Generate goog.provides() calls.
+  void FindProvides(const GeneratorOptions& options,
+                    io::Printer* printer,
+                    const vector<const FileDescriptor*>& file,
+                    std::set<string>* provided) const;
+  void FindProvidesForMessage(const GeneratorOptions& options,
+                              io::Printer* printer,
+                              const Descriptor* desc,
+                              std::set<string>* provided) const;
+  void FindProvidesForEnum(const GeneratorOptions& options,
+                           io::Printer* printer,
+                           const EnumDescriptor* enumdesc,
+                           std::set<string>* provided) const;
+  // For extension fields at file scope.
+  void FindProvidesForFields(const GeneratorOptions& options,
+                             io::Printer* printer,
+                             const vector<const FieldDescriptor*>& fields,
+                             std::set<string>* provided) const;
+  // Print the goog.provides() found by the methods above.
+  void GenerateProvides(const GeneratorOptions& options,
+                        io::Printer* printer,
+                        std::set<string>* provided) const;
+
+  // Generate goog.setTestOnly() if indicated.
+  void GenerateTestOnly(const GeneratorOptions& options,
+                        io::Printer* printer) const;
+
+  // Generate goog.requires() calls.
+  void GenerateRequires(const GeneratorOptions& options,
+                        io::Printer* printer,
+                        const vector<const FileDescriptor*>& file,
+                        std::set<string>* provided) const;
+  void GenerateRequires(const GeneratorOptions& options,
+                        io::Printer* printer,
+                        const Descriptor* desc,
+                        std::set<string>* provided) const;
+  // For extension fields at file scope.
+  void GenerateRequires(const GeneratorOptions& options,
+                        io::Printer* printer,
+                        const vector<const FieldDescriptor*>& fields,
+                        std::set<string>* provided) const;
+  void GenerateRequiresImpl(const GeneratorOptions& options,
+                            io::Printer* printer,
+                            std::set<string>* required,
+                            std::set<string>* forwards,
+                            std::set<string>* provided,
+                            bool require_jspb,
+                            bool require_extension) const;
+  void FindRequiresForMessage(const GeneratorOptions& options,
+                              const Descriptor* desc,
+                              std::set<string>* required,
+                              std::set<string>* forwards,
+                              bool* have_message) const;
+  void FindRequiresForField(const GeneratorOptions& options,
+                            const FieldDescriptor* field,
+                            std::set<string>* required,
+                            std::set<string>* forwards) const;
+  void FindRequiresForExtension(const GeneratorOptions& options,
+                                const FieldDescriptor* field,
+                                std::set<string>* required,
+                                std::set<string>* forwards) const;
+
+  // Generate definitions for all message classes and enums in all files,
+  // processing the files in dependence order.
+  void GenerateFilesInDepOrder(const GeneratorOptions& options,
+                               io::Printer* printer,
+                               const vector<const FileDescriptor*>& file) const;
+  // Helper for above.
+  void GenerateFileAndDeps(const GeneratorOptions& options,
+                           io::Printer* printer,
+                           const FileDescriptor* root,
+                           std::set<const FileDescriptor*>* all_files,
+                           std::set<const FileDescriptor*>* generated) const;
+
+  // Generate definitions for all message classes and enums.
+  void GenerateClassesAndEnums(const GeneratorOptions& options,
+                               io::Printer* printer,
+                               const FileDescriptor* file) const;
+
+  // Generate definition for one class.
+  void GenerateClass(const GeneratorOptions& options,
+                     io::Printer* printer,
+                     const Descriptor* desc) const;
+  void GenerateClassConstructor(const GeneratorOptions& options,
+                                io::Printer* printer,
+                                const Descriptor* desc) const;
+  void GenerateClassFieldInfo(const GeneratorOptions& options,
+                              io::Printer* printer,
+                              const Descriptor* desc) const;
+  void GenerateClassXid(const GeneratorOptions& options,
+                        io::Printer* printer,
+                        const Descriptor* desc) const;
+  void GenerateOneofCaseDefinition(const GeneratorOptions& options,
+                                   io::Printer* printer,
+                                   const OneofDescriptor* oneof) const;
+  void GenerateClassToObject(const GeneratorOptions& options,
+                             io::Printer* printer,
+                             const Descriptor* desc) const;
+  void GenerateClassFieldToObject(const GeneratorOptions& options,
+                                  io::Printer* printer,
+                                  const FieldDescriptor* field) const;
+  void GenerateClassFromObject(const GeneratorOptions& options,
+                               io::Printer* printer,
+                               const Descriptor* desc) const;
+  void GenerateClassFieldFromObject(const GeneratorOptions& options,
+                                    io::Printer* printer,
+                                    const FieldDescriptor* field) const;
+  void GenerateClassClone(const GeneratorOptions& options,
+                          io::Printer* printer,
+                          const Descriptor* desc) const;
+  void GenerateClassRegistration(const GeneratorOptions& options,
+                                 io::Printer* printer,
+                                 const Descriptor* desc) const;
+  void GenerateClassFields(const GeneratorOptions& options,
+                           io::Printer* printer,
+                           const Descriptor* desc) const;
+  void GenerateClassField(const GeneratorOptions& options,
+                          io::Printer* printer,
+                          const FieldDescriptor* desc) const;
+  void GenerateClassExtensionFieldInfo(const GeneratorOptions& options,
+                                       io::Printer* printer,
+                                       const Descriptor* desc) const;
+  void GenerateClassDeserialize(const GeneratorOptions& options,
+                                io::Printer* printer,
+                                const Descriptor* desc) const;
+  void GenerateClassDeserializeBinary(const GeneratorOptions& options,
+                                      io::Printer* printer,
+                                      const Descriptor* desc) const;
+  void GenerateClassDeserializeBinaryField(const GeneratorOptions& options,
+                                           io::Printer* printer,
+                                           const FieldDescriptor* field) const;
+  void GenerateClassSerializeBinary(const GeneratorOptions& options,
+                                    io::Printer* printer,
+                                    const Descriptor* desc) const;
+  void GenerateClassSerializeBinaryField(const GeneratorOptions& options,
+                                         io::Printer* printer,
+                                         const FieldDescriptor* field) const;
+
+  // Generate definition for one enum.
+  void GenerateEnum(const GeneratorOptions& options,
+                    io::Printer* printer,
+                    const EnumDescriptor* enumdesc) const;
+
+  // Generate an extension definition.
+  void GenerateExtension(const GeneratorOptions& options,
+                         io::Printer* printer,
+                         const FieldDescriptor* field) const;
+
+  GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Generator);
+};
+
+}  // namespace js
+}  // namespace compiler
+}  // namespace protobuf
+
+}  // namespace google
+#endif  // GOOGLE_PROTOBUF_COMPILER_JS_GENERATOR_H__
diff --git a/src/google/protobuf/compiler/main.cc b/src/google/protobuf/compiler/main.cc
index 584e5a40..97df536e 100644
--- a/src/google/protobuf/compiler/main.cc
+++ b/src/google/protobuf/compiler/main.cc
@@ -38,6 +38,7 @@
 #include <google/protobuf/compiler/ruby/ruby_generator.h>
 #include <google/protobuf/compiler/csharp/csharp_generator.h>
 #include <google/protobuf/compiler/objectivec/objectivec_generator.h>
+#include <google/protobuf/compiler/js/js_generator.h>
 
 int main(int argc, char* argv[]) {
 
@@ -80,5 +81,10 @@ int main(int argc, char* argv[]) {
   cli.RegisterGenerator("--objc_out", &objc_generator,
                         "Generate Objective C header and source.");
 
+  // JavaScript
+  google::protobuf::compiler::js::Generator js_generator;
+  cli.RegisterGenerator("--js_out", &js_generator,
+                        "Generate JavaScript source.");
+
   return cli.Run(argc, argv);
 }
diff --git a/src/google/protobuf/compiler/mock_code_generator.cc b/src/google/protobuf/compiler/mock_code_generator.cc
index 98261431..121d917b 100644
--- a/src/google/protobuf/compiler/mock_code_generator.cc
+++ b/src/google/protobuf/compiler/mock_code_generator.cc
@@ -147,6 +147,12 @@ bool MockCodeGenerator::Generate(
         std::cerr << "Saw message type MockCodeGenerator_HasSourceCodeInfo: "
                   << has_source_code_info << "." << std::endl;
         abort();
+      } else if (command == "HasJsonName") {
+        FieldDescriptorProto field_descriptor_proto;
+        file->message_type(i)->field(0)->CopyTo(&field_descriptor_proto);
+        std::cerr << "Saw json_name: "
+                  << field_descriptor_proto.has_json_name() << std::endl;
+        abort();
       } else {
         GOOGLE_LOG(FATAL) << "Unknown MockCodeGenerator command: " << command;
       }
diff --git a/src/google/protobuf/compiler/parser.cc b/src/google/protobuf/compiler/parser.cc
index a389a4fc..ea792a9d 100644
--- a/src/google/protobuf/compiler/parser.cc
+++ b/src/google/protobuf/compiler/parser.cc
@@ -458,6 +458,61 @@ void Parser::SkipRestOfBlock() {
 
 // ===================================================================
 
+bool Parser::ValidateEnum(const EnumDescriptorProto* proto) {
+  bool has_allow_alias = false;
+  bool allow_alias = false;
+
+  for (int i = 0; i < proto->options().uninterpreted_option_size(); i++) {
+    const UninterpretedOption option = proto->options().uninterpreted_option(i);
+    if (option.name_size() > 1) {
+      continue;
+    }
+    if (!option.name(0).is_extension() &&
+        option.name(0).name_part() == "allow_alias") {
+      has_allow_alias = true;
+      if (option.identifier_value() == "true") {
+        allow_alias = true;
+      }
+      break;
+    }
+  }
+
+  if (has_allow_alias && !allow_alias) {
+    string error =
+        "\"" + proto->name() +
+        "\" declares 'option allow_alias = false;' which has no effect. "
+        "Please remove the declaration.";
+    // This needlessly clutters declarations with nops.
+    AddError(error);
+    return false;
+  }
+
+  set<int> used_values;
+  bool has_duplicates = false;
+  for (int i = 0; i < proto->value_size(); ++i) {
+    const EnumValueDescriptorProto enum_value = proto->value(i);
+    if (used_values.find(enum_value.number()) != used_values.end()) {
+      has_duplicates = true;
+      break;
+    } else {
+      used_values.insert(enum_value.number());
+    }
+  }
+  if (allow_alias && !has_duplicates) {
+    string error =
+        "\"" + proto->name() +
+        "\" declares support for enum aliases but no enum values share field "
+        "numbers. Please remove the unnecessary 'option allow_alias = true;' "
+        "declaration.";
+    // Generate an error if an enum declares support for duplicate enum values
+    // and does not use it protect future authors.
+    AddError(error);
+    return false;
+  }
+
+  return true;
+}
+
 bool Parser::Parse(io::Tokenizer* input, FileDescriptorProto* file) {
   input_ = input;
   had_errors_ = false;
@@ -1627,6 +1682,9 @@ bool Parser::ParseEnumDefinition(EnumDescriptorProto* enum_type,
   }
 
   DO(ParseEnumBlock(enum_type, enum_location, containing_file));
+
+  DO(ValidateEnum(enum_type));
+
   return true;
 }
 
diff --git a/src/google/protobuf/compiler/parser.h b/src/google/protobuf/compiler/parser.h
index 3ba1e170..2c561c23 100644
--- a/src/google/protobuf/compiler/parser.h
+++ b/src/google/protobuf/compiler/parser.h
@@ -498,6 +498,8 @@ class LIBPROTOBUF_EXPORT Parser {
   }
 
 
+  bool ValidateEnum(const EnumDescriptorProto* proto);
+
   // =================================================================
 
   io::Tokenizer* input_;
diff --git a/src/google/protobuf/compiler/parser_unittest.cc b/src/google/protobuf/compiler/parser_unittest.cc
index 0d729e0b..1d623dd9 100644
--- a/src/google/protobuf/compiler/parser_unittest.cc
+++ b/src/google/protobuf/compiler/parser_unittest.cc
@@ -1170,6 +1170,29 @@ TEST_F(ParseErrorTest, EnumValueOutOfRange) {
     "4:19: Integer out of range.\n");
 }
 
+TEST_F(ParseErrorTest, EnumAllowAliasFalse) {
+  ExpectHasErrors(
+    "enum Foo {\n"
+    "  option allow_alias = false;\n"
+    "  BAR = 1;\n"
+    "  BAZ = 2;\n"
+    "}\n",
+    "5:0: \"Foo\" declares 'option allow_alias = false;' which has no effect. "
+    "Please remove the declaration.\n");
+}
+
+TEST_F(ParseErrorTest, UnnecessaryEnumAllowAlias) {
+  ExpectHasErrors(
+    "enum Foo {\n"
+    "  option allow_alias = true;\n"
+    "  BAR = 1;\n"
+    "  BAZ = 2;\n"
+    "}\n",
+    "5:0: \"Foo\" declares support for enum aliases but no enum values share "
+    "field numbers. Please remove the unnecessary 'option allow_alias = true;' "
+    "declaration.\n");
+}
+
 TEST_F(ParseErrorTest, DefaultValueMissing) {
   ExpectHasErrors(
     "message TestMessage {\n"
@@ -1839,6 +1862,8 @@ TEST_F(ParseDescriptorDebugTest, TestCommentsInDebugString) {
       "// Detached comment before TestMessage1.\n"
       "\n"
       "// Message comment.\n"
+      "//\n"
+      "// More detail in message comment.\n"
       "message TestMessage1 {\n"
       "\n"
       "  // Detached comment before foo.\n"
@@ -1890,11 +1915,6 @@ TEST_F(ParseDescriptorDebugTest, TestCommentsInDebugString) {
       pool_.BuildFileCollectingErrors(parsed_desc, &collector);
   ASSERT_TRUE(descriptor != NULL);
 
-  DebugStringOptions debug_string_options;
-  debug_string_options.include_comments = true;
-  const string debug_string =
-      descriptor->DebugStringWithOptions(debug_string_options);
-
   // Ensure that each of the comments appears somewhere in the DebugString().
   // We don't test the exact comment placement or formatting, because we do not
   // want to be too fragile here.
@@ -1905,6 +1925,7 @@ TEST_F(ParseDescriptorDebugTest, TestCommentsInDebugString) {
     "Package comment.",
     "Detached comment before TestMessage1.",
     "Message comment.",
+    "More detail in message comment.",
     "Detached comment before foo.",
     "Field comment",
     "Detached comment before NestedMessage.",
@@ -1919,11 +1940,28 @@ TEST_F(ParseDescriptorDebugTest, TestCommentsInDebugString) {
     "RPC comment",
   };
 
-  for (int i = 0; i < GOOGLE_ARRAYSIZE(expected_comments); ++i) {
-    string::size_type found_pos = debug_string.find(expected_comments[i]);
-    EXPECT_TRUE(found_pos != string::npos)
-        << "\"" << expected_comments[i] << "\" not found.";
+  DebugStringOptions debug_string_options;
+  debug_string_options.include_comments = true;
+
+  {
+    const string debug_string =
+        descriptor->DebugStringWithOptions(debug_string_options);
+
+    for (int i = 0; i < GOOGLE_ARRAYSIZE(expected_comments); ++i) {
+      string::size_type found_pos = debug_string.find(expected_comments[i]);
+      EXPECT_TRUE(found_pos != string::npos)
+          << "\"" << expected_comments[i] << "\" not found.";
+    }
+
+    // Result of DebugStringWithOptions should be parseable.
+    SetupParser(debug_string.c_str());
+    FileDescriptorProto parsed;
+    parser_->Parse(input_.get(), &parsed);
+    EXPECT_EQ(io::Tokenizer::TYPE_END, input_->current().type);
+    ASSERT_EQ("", error_collector_.text_)
+        << "Failed to parse:\n" << debug_string;
   }
+
 }
 
 TEST_F(ParseDescriptorDebugTest, TestMaps) {
diff --git a/src/google/protobuf/compiler/plugin.pb.cc b/src/google/protobuf/compiler/plugin.pb.cc
index 636673ae..a2da8eee 100644
--- a/src/google/protobuf/compiler/plugin.pb.cc
+++ b/src/google/protobuf/compiler/plugin.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
diff --git a/src/google/protobuf/compiler/subprocess.cc b/src/google/protobuf/compiler/subprocess.cc
index 85429924..a30ac305 100644
--- a/src/google/protobuf/compiler/subprocess.cc
+++ b/src/google/protobuf/compiler/subprocess.cc
@@ -47,6 +47,7 @@
 #include <google/protobuf/message.h>
 #include <google/protobuf/stubs/substitute.h>
 
+
 namespace google {
 namespace protobuf {
 namespace compiler {
diff --git a/src/google/protobuf/descriptor.cc b/src/google/protobuf/descriptor.cc
index 9a1c6fe8..1aac360b 100644
--- a/src/google/protobuf/descriptor.cc
+++ b/src/google/protobuf/descriptor.cc
@@ -2050,6 +2050,7 @@ class SourceLocationCommentPrinter {
   }
 
  private:
+
   bool have_source_loc_;
   SourceLocation source_loc_;
   DebugStringOptions options_;
@@ -2951,7 +2952,8 @@ class DescriptorBuilder {
                    const ServiceDescriptor* parent,
                    MethodDescriptor* result);
 
-  void LogUnusedDependency(const FileDescriptor* result);
+  void LogUnusedDependency(const FileDescriptorProto& proto,
+                           const FileDescriptor* result);
 
   // Must be run only after building.
   //
@@ -3996,7 +3998,7 @@ const FileDescriptor* DescriptorBuilder::BuildFile(
 
 
   if (!unused_dependency_.empty()) {
-    LogUnusedDependency(result);
+    LogUnusedDependency(proto, result);
   }
 
   if (had_errors_) {
@@ -4143,6 +4145,7 @@ void DescriptorBuilder::BuildMessage(const DescriptorProto& proto,
   }
 }
 
+
 void DescriptorBuilder::BuildFieldOrExtension(const FieldDescriptorProto& proto,
                                               const Descriptor* parent,
                                               FieldDescriptor* result,
@@ -4248,8 +4251,8 @@ void DescriptorBuilder::BuildFieldOrExtension(const FieldDescriptorProto& proto,
           } else if (proto.default_value() == "nan") {
             result->default_value_float_ = numeric_limits<float>::quiet_NaN();
           } else  {
-            result->default_value_float_ =
-              io::NoLocaleStrtod(proto.default_value().c_str(), &end_pos);
+            result->default_value_float_ = io::SafeDoubleToFloat(
+                io::NoLocaleStrtod(proto.default_value().c_str(), &end_pos));
           }
           break;
         case FieldDescriptor::CPPTYPE_DOUBLE:
@@ -4421,6 +4424,7 @@ void DescriptorBuilder::BuildFieldOrExtension(const FieldDescriptorProto& proto,
     AllocateOptions(proto.options(), result);
   }
 
+
   AddSymbol(result->full_name(), parent, result->name(),
             proto, Symbol(result));
 }
@@ -5533,11 +5537,19 @@ bool DescriptorBuilder::OptionInterpreter::InterpretOptions(
     // UnknownFieldSet and wait there until the message is parsed by something
     // that does know about the options.
     string buf;
-    options->AppendToString(&buf);
-    GOOGLE_CHECK(options->ParseFromString(buf))
+    GOOGLE_CHECK(options->AppendPartialToString(&buf))
+        << "Protocol message could not be serialized.";
+    GOOGLE_CHECK(options->ParsePartialFromString(buf))
         << "Protocol message serialized itself in invalid fashion.";
+    if (!options->IsInitialized()) {
+      builder_->AddWarning(
+          options_to_interpret->element_name, *original_options,
+          DescriptorPool::ErrorCollector::OTHER,
+          "Options could not be fully parsed using the proto descriptors "
+          "compiled into this binary. Missing required fields: " +
+          options->InitializationErrorString());
+    }
   }
-
   return !failed;
 }
 
@@ -6191,7 +6203,8 @@ void DescriptorBuilder::OptionInterpreter::SetUInt64(int number, uint64 value,
   }
 }
 
-void DescriptorBuilder::LogUnusedDependency(const FileDescriptor* result) {
+void DescriptorBuilder::LogUnusedDependency(const FileDescriptorProto& proto,
+                                            const FileDescriptor* result) {
 
   if (!unused_dependency_.empty()) {
     std::set<string> annotation_extensions;
@@ -6217,9 +6230,9 @@ void DescriptorBuilder::LogUnusedDependency(const FileDescriptor* result) {
       }
       // Log warnings for unused imported files.
       if (i == (*it)->extension_count()) {
-        GOOGLE_LOG(WARNING) << "Warning: Unused import: \"" << result->name()
-                     << "\" imports \"" << (*it)->name()
-                     << "\" which is not used.";
+        string error_message = "Import " + (*it)->name() + " but not used.";
+        AddWarning((*it)->name(), proto, DescriptorPool::ErrorCollector::OTHER,
+                   error_message);
       }
     }
   }
diff --git a/src/google/protobuf/descriptor.pb.cc b/src/google/protobuf/descriptor.pb.cc
index bc846609..eda6280f 100644
--- a/src/google/protobuf/descriptor.pb.cc
+++ b/src/google/protobuf/descriptor.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
diff --git a/src/google/protobuf/descriptor_unittest.cc b/src/google/protobuf/descriptor_unittest.cc
index ccd0650d..be8e0b72 100644
--- a/src/google/protobuf/descriptor_unittest.cc
+++ b/src/google/protobuf/descriptor_unittest.cc
@@ -178,6 +178,61 @@ void AddEmptyEnum(FileDescriptorProto* file, const string& name) {
   AddEnumValue(AddEnum(file, name), name + "_DUMMY", 1);
 }
 
+class MockErrorCollector : public DescriptorPool::ErrorCollector {
+ public:
+  MockErrorCollector() {}
+  ~MockErrorCollector() {}
+
+  string text_;
+  string warning_text_;
+
+  // implements ErrorCollector ---------------------------------------
+  void AddError(const string& filename,
+                const string& element_name, const Message* descriptor,
+                ErrorLocation location, const string& message) {
+    const char* location_name = NULL;
+    switch (location) {
+      case NAME         : location_name = "NAME"         ; break;
+      case NUMBER       : location_name = "NUMBER"       ; break;
+      case TYPE         : location_name = "TYPE"         ; break;
+      case EXTENDEE     : location_name = "EXTENDEE"     ; break;
+      case DEFAULT_VALUE: location_name = "DEFAULT_VALUE"; break;
+      case OPTION_NAME  : location_name = "OPTION_NAME"  ; break;
+      case OPTION_VALUE : location_name = "OPTION_VALUE" ; break;
+      case INPUT_TYPE   : location_name = "INPUT_TYPE"   ; break;
+      case OUTPUT_TYPE  : location_name = "OUTPUT_TYPE"  ; break;
+      case OTHER        : location_name = "OTHER"        ; break;
+    }
+
+    strings::SubstituteAndAppend(
+      &text_, "$0: $1: $2: $3\n",
+      filename, element_name, location_name, message);
+  }
+
+  // implements ErrorCollector ---------------------------------------
+  void AddWarning(const string& filename, const string& element_name,
+                  const Message* descriptor, ErrorLocation location,
+                  const string& message) {
+    const char* location_name = NULL;
+    switch (location) {
+      case NAME         : location_name = "NAME"         ; break;
+      case NUMBER       : location_name = "NUMBER"       ; break;
+      case TYPE         : location_name = "TYPE"         ; break;
+      case EXTENDEE     : location_name = "EXTENDEE"     ; break;
+      case DEFAULT_VALUE: location_name = "DEFAULT_VALUE"; break;
+      case OPTION_NAME  : location_name = "OPTION_NAME"  ; break;
+      case OPTION_VALUE : location_name = "OPTION_VALUE" ; break;
+      case INPUT_TYPE   : location_name = "INPUT_TYPE"   ; break;
+      case OUTPUT_TYPE  : location_name = "OUTPUT_TYPE"  ; break;
+      case OTHER        : location_name = "OTHER"        ; break;
+    }
+
+    strings::SubstituteAndAppend(
+      &warning_text_, "$0: $1: $2: $3\n",
+      filename, element_name, location_name, message);
+  }
+};
+
 // ===================================================================
 
 // Test simple files.
@@ -3120,77 +3175,95 @@ TEST(CustomOptions, UnusedImportWarning) {
       ->file()->CopyTo(&file_proto);
   ASSERT_TRUE(pool.BuildFile(file_proto) != NULL);
 
-
   pool.AddUnusedImportTrackFile("custom_options_import.proto");
   ASSERT_TRUE(TextFormat::ParseFromString(
     "name: \"custom_options_import.proto\" "
     "package: \"protobuf_unittest\" "
     "dependency: \"google/protobuf/unittest_custom_options.proto\" ",
     &file_proto));
-  pool.BuildFile(file_proto);
-}
 
-// ===================================================================
+  MockErrorCollector error_collector;
+  EXPECT_TRUE(pool.BuildFileCollectingErrors(file_proto, &error_collector));
+  EXPECT_EQ("", error_collector.warning_text_);
+}
 
-// The tests below trigger every unique call to AddError() in descriptor.cc,
-// in the order in which they appear in that file.  I'm using TextFormat here
-// to specify the input descriptors because building them using code would
-// be too bulky.
+// Verifies that proto files can correctly be parsed, even if the
+// custom options defined in the file are incompatible with those
+// compiled in the binary. See http://b/19276250.
+TEST(CustomOptions, OptionsWithRequiredEnums) {
+  DescriptorPool pool;
 
-class MockErrorCollector : public DescriptorPool::ErrorCollector {
- public:
-  MockErrorCollector() {}
-  ~MockErrorCollector() {}
+  FileDescriptorProto file_proto;
+  MessageOptions::descriptor()->file()->CopyTo(&file_proto);
+  ASSERT_TRUE(pool.BuildFile(file_proto) != NULL);
 
-  string text_;
-  string warning_text_;
+  // Create a new file descriptor proto containing a subset of the
+  // messages defined in google/protobuf/unittest_custom_options.proto.
+  file_proto.Clear();
+  file_proto.set_name("unittest_custom_options.proto");
+  file_proto.set_package("protobuf_unittest");
+  file_proto.add_dependency("google/protobuf/descriptor.proto");
 
-  // implements ErrorCollector ---------------------------------------
-  void AddError(const string& filename,
-                const string& element_name, const Message* descriptor,
-                ErrorLocation location, const string& message) {
-    const char* location_name = NULL;
-    switch (location) {
-      case NAME         : location_name = "NAME"         ; break;
-      case NUMBER       : location_name = "NUMBER"       ; break;
-      case TYPE         : location_name = "TYPE"         ; break;
-      case EXTENDEE     : location_name = "EXTENDEE"     ; break;
-      case DEFAULT_VALUE: location_name = "DEFAULT_VALUE"; break;
-      case OPTION_NAME  : location_name = "OPTION_NAME"  ; break;
-      case OPTION_VALUE : location_name = "OPTION_VALUE" ; break;
-      case INPUT_TYPE   : location_name = "INPUT_TYPE"   ; break;
-      case OUTPUT_TYPE  : location_name = "OUTPUT_TYPE"  ; break;
-      case OTHER        : location_name = "OTHER"        ; break;
-    }
+  // Add the "required_enum_opt" extension.
+  FieldDescriptorProto* extension = file_proto.add_extension();
+  protobuf_unittest::OldOptionType::descriptor()->file()
+      ->FindExtensionByName("required_enum_opt")->CopyTo(extension);
+
+  // Add a test message that uses the "required_enum_opt" option.
+  DescriptorProto* test_message_type = file_proto.add_message_type();
+  protobuf_unittest::TestMessageWithRequiredEnumOption::descriptor()
+      ->CopyTo(test_message_type);
+
+  // Instruct the extension to use NewOptionType instead of
+  // OldOptionType, and add the descriptor of NewOptionType.
+  extension->set_type_name(".protobuf_unittest.NewOptionType");
+  DescriptorProto* new_option_type = file_proto.add_message_type();
+  protobuf_unittest::NewOptionType::descriptor()
+      ->CopyTo(new_option_type);
+
+  // Replace the value of the "required_enum_opt" option used in the
+  // test message with an enum value that only exists in NewOptionType.
+  ASSERT_TRUE(TextFormat::ParseFromString(
+      "uninterpreted_option { "
+      "  name { "
+      "    name_part: 'required_enum_opt' "
+      "    is_extension: true "
+      "  } "
+      "  aggregate_value: 'value: NEW_VALUE' "
+      "}",
+      test_message_type->mutable_options()));
 
-    strings::SubstituteAndAppend(
-      &text_, "$0: $1: $2: $3\n",
-      filename, element_name, location_name, message);
-  }
+  // Add the file descriptor to the pool.
+  ASSERT_TRUE(pool.BuildFile(file_proto) != NULL);
 
-  // implements ErrorCollector ---------------------------------------
-  void AddWarning(const string& filename, const string& element_name,
-                  const Message* descriptor, ErrorLocation location,
-                  const string& message) {
-    const char* location_name = NULL;
-    switch (location) {
-      case NAME         : location_name = "NAME"         ; break;
-      case NUMBER       : location_name = "NUMBER"       ; break;
-      case TYPE         : location_name = "TYPE"         ; break;
-      case EXTENDEE     : location_name = "EXTENDEE"     ; break;
-      case DEFAULT_VALUE: location_name = "DEFAULT_VALUE"; break;
-      case OPTION_NAME  : location_name = "OPTION_NAME"  ; break;
-      case OPTION_VALUE : location_name = "OPTION_VALUE" ; break;
-      case INPUT_TYPE   : location_name = "INPUT_TYPE"   ; break;
-      case OUTPUT_TYPE  : location_name = "OUTPUT_TYPE"  ; break;
-      case OTHER        : location_name = "OTHER"        ; break;
-    }
+  // Find the test message.
+  const Descriptor* test_message = pool.FindMessageTypeByName(
+      "protobuf_unittest.TestMessageWithRequiredEnumOption");
+  ASSERT_TRUE(test_message != NULL);
+
+  const MessageOptions& options = test_message->options();
+  // Extract the "required_enum_opt" option. Since the binary does not
+  // know that the extension was updated, this will still return an
+  // OldOptionType message.
+  ASSERT_TRUE(
+      options.HasExtension(protobuf_unittest::required_enum_opt));
+  const protobuf_unittest::OldOptionType& old_enum_opt =
+      options.GetExtension(protobuf_unittest::required_enum_opt);
+
+  // Confirm that the required enum field is missing.
+  EXPECT_FALSE(old_enum_opt.IsInitialized());
+  EXPECT_FALSE(old_enum_opt.has_value());
+
+  string buf;
+  // Verify that the required enum field does show up when the option
+  // is re-parsed as a NewOptionType message;
+  protobuf_unittest::NewOptionType new_enum_opt;
+  EXPECT_TRUE(old_enum_opt.AppendPartialToString(&buf));
+  EXPECT_TRUE(new_enum_opt.ParseFromString(buf));
+  EXPECT_EQ(protobuf_unittest::NewOptionType::NEW_VALUE, new_enum_opt.value());
+}
 
-    strings::SubstituteAndAppend(
-      &warning_text_, "$0: $1: $2: $3\n",
-      filename, element_name, location_name, message);
-  }
-};
+// ===================================================================
 
 class ValidationErrorTest : public testing::Test {
  protected:
@@ -5123,7 +5196,6 @@ TEST_F(ValidationErrorTest, AllowEnumAlias) {
 }
 
 TEST_F(ValidationErrorTest, UnusedImportWarning) {
-
   pool_.AddUnusedImportTrackFile("bar.proto");
   BuildFile(
     "name: \"bar.proto\" "
@@ -5155,7 +5227,7 @@ TEST_F(ValidationErrorTest, UnusedImportWarning) {
   // }
   //
   pool_.AddUnusedImportTrackFile("forward.proto");
-  BuildFile(
+  BuildFileWithWarnings(
     "name: \"forward.proto\""
     "dependency: \"base.proto\""
     "dependency: \"bar.proto\""
@@ -5165,7 +5237,8 @@ TEST_F(ValidationErrorTest, UnusedImportWarning) {
     "message_type {"
     "  name: \"Forward\""
     "  field { name:\"base\" number:1 label:LABEL_OPTIONAL type_name:\"Base\" }"
-    "}");
+    "}",
+    "forward.proto: bar.proto: OTHER: Import bar.proto but not used.\n");
 }
 
 namespace {
diff --git a/src/google/protobuf/duration.pb.cc b/src/google/protobuf/duration.pb.cc
index c7eed0d5..b325944e 100644
--- a/src/google/protobuf/duration.pb.cc
+++ b/src/google/protobuf/duration.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
diff --git a/src/google/protobuf/duration.proto b/src/google/protobuf/duration.proto
index 7f172aa6..78bcc74b 100644
--- a/src/google/protobuf/duration.proto
+++ b/src/google/protobuf/duration.proto
@@ -27,15 +27,16 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
 package google.protobuf;
 
-option java_generate_equals_and_hash = true;
-option java_multiple_files = true;
-option java_outer_classname = "DurationProto";
-option java_package = "com.google.protobuf";
 option csharp_namespace = "Google.Protobuf.WellKnownTypes";
+option java_package = "com.google.protobuf";
+option java_outer_classname = "DurationProto";
+option java_multiple_files = true;
+option java_generate_equals_and_hash = true;
 option objc_class_prefix = "GPB";
 
 // A Duration represents a signed, fixed-length span of time represented
diff --git a/src/google/protobuf/dynamic_message.cc b/src/google/protobuf/dynamic_message.cc
index 091fc975..bb400476 100644
--- a/src/google/protobuf/dynamic_message.cc
+++ b/src/google/protobuf/dynamic_message.cc
@@ -69,8 +69,8 @@
 #include <google/protobuf/stubs/shared_ptr.h>
 #endif
 
-#include <google/protobuf/stubs/scoped_ptr.h>
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/scoped_ptr.h>
 
 #include <google/protobuf/dynamic_message.h>
 #include <google/protobuf/descriptor.h>
diff --git a/src/google/protobuf/empty.pb.cc b/src/google/protobuf/empty.pb.cc
index 4a4f6eae..f2eec782 100644
--- a/src/google/protobuf/empty.pb.cc
+++ b/src/google/protobuf/empty.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
@@ -79,9 +80,9 @@ void protobuf_AddDesc_google_2fprotobuf_2fempty_2eproto() {
 
   ::google::protobuf::DescriptorPool::InternalAddGeneratedFile(
     "\n\033google/protobuf/empty.proto\022\017google.pr"
-    "otobuf\"\007\n\005EmptyBM\n\023com.google.protobufB\n"
-    "EmptyProtoP\001\240\001\001\242\002\003GPB\252\002\036Google.Protobuf."
-    "WellKnownTypesb\006proto3", 142);
+    "otobuf\"\007\n\005EmptyBP\n\023com.google.protobufB\n"
+    "EmptyProtoP\001\240\001\001\370\001\001\242\002\003GPB\252\002\036Google.Protob"
+    "uf.WellKnownTypesb\006proto3", 145);
   ::google::protobuf::MessageFactory::InternalRegisterGeneratedFile(
     "google/protobuf/empty.proto", &protobuf_RegisterTypes);
   Empty::default_instance_ = new Empty();
@@ -117,6 +118,14 @@ Empty::Empty()
   // @@protoc_insertion_point(constructor:google.protobuf.Empty)
 }
 
+Empty::Empty(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.Empty)
+}
+
 void Empty::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -140,10 +149,20 @@ Empty::~Empty() {
 }
 
 void Empty::SharedDtor() {
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
   if (this != default_instance_) {
   }
 }
 
+void Empty::ArenaDtor(void* object) {
+  Empty* _this = reinterpret_cast< Empty* >(object);
+  (void)_this;
+}
+void Empty::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void Empty::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -162,11 +181,7 @@ const Empty& Empty::default_instance() {
 Empty* Empty::default_instance_ = NULL;
 
 Empty* Empty::New(::google::protobuf::Arena* arena) const {
-  Empty* n = new Empty;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<Empty>(arena);
 }
 
 void Empty::Clear() {
@@ -255,6 +270,18 @@ bool Empty::IsInitialized() const {
 
 void Empty::Swap(Empty* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    Empty temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void Empty::UnsafeArenaSwap(Empty* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void Empty::InternalSwap(Empty* other) {
diff --git a/src/google/protobuf/empty.pb.h b/src/google/protobuf/empty.pb.h
index 20876bea..868009fc 100644
--- a/src/google/protobuf/empty.pb.h
+++ b/src/google/protobuf/empty.pb.h
@@ -53,9 +53,14 @@ class LIBPROTOBUF_EXPORT Empty : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const Empty& default_instance();
 
+  void UnsafeArenaSwap(Empty* other);
   void Swap(Empty* other);
 
   // implements Message ----------------------------------------------
@@ -82,6 +87,11 @@ class LIBPROTOBUF_EXPORT Empty : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(Empty* other);
+  protected:
+  explicit Empty(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -101,6 +111,9 @@ class LIBPROTOBUF_EXPORT Empty : public ::google::protobuf::Message {
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   mutable int _cached_size_;
   friend void LIBPROTOBUF_EXPORT protobuf_AddDesc_google_2fprotobuf_2fempty_2eproto();
diff --git a/src/google/protobuf/empty.proto b/src/google/protobuf/empty.proto
index 9dddc6c5..b96daf28 100644
--- a/src/google/protobuf/empty.proto
+++ b/src/google/protobuf/empty.proto
@@ -27,16 +27,18 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
 package google.protobuf;
 
-option java_multiple_files = true;
-option java_outer_classname = "EmptyProto";
+option csharp_namespace = "Google.Protobuf.WellKnownTypes";
 option java_package = "com.google.protobuf";
+option java_outer_classname = "EmptyProto";
+option java_multiple_files = true;
 option java_generate_equals_and_hash = true;
-option csharp_namespace = "Google.Protobuf.WellKnownTypes";
 option objc_class_prefix = "GPB";
+option cc_enable_arenas = true;
 
 // A generic empty message that you can re-use to avoid defining duplicated
 // empty messages in your APIs. A typical example is to use it as the request
diff --git a/src/google/protobuf/field_mask.pb.cc b/src/google/protobuf/field_mask.pb.cc
index f834363b..01a6ce56 100644
--- a/src/google/protobuf/field_mask.pb.cc
+++ b/src/google/protobuf/field_mask.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
diff --git a/src/google/protobuf/field_mask.proto b/src/google/protobuf/field_mask.proto
index 8b21c692..908c8a86 100644
--- a/src/google/protobuf/field_mask.proto
+++ b/src/google/protobuf/field_mask.proto
@@ -27,16 +27,17 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
 package google.protobuf;
 
-option java_generate_equals_and_hash = true;
-option java_multiple_files = true;
-option java_outer_classname = "FieldMaskProto";
-option java_package = "com.google.protobuf";
 option csharp_namespace = "Google.Protobuf.WellKnownTypes";
+option java_package = "com.google.protobuf";
+option java_outer_classname = "FieldMaskProto";
+option java_multiple_files = true;
 option objc_class_prefix = "GPB";
+option java_generate_equals_and_hash = true;
 
 // `FieldMask` represents a set of symbolic field paths, for example:
 //
@@ -69,7 +70,7 @@ option objc_class_prefix = "GPB";
 //     z: 8
 //
 // The result will not contain specific values for fields x,y and z
-// (there value will be set to the default, and omitted in proto text
+// (their value will be set to the default, and omitted in proto text
 // output):
 //
 //
diff --git a/src/google/protobuf/io/coded_stream.h b/src/google/protobuf/io/coded_stream.h
index cb1869a7..2da096c5 100644
--- a/src/google/protobuf/io/coded_stream.h
+++ b/src/google/protobuf/io/coded_stream.h
@@ -109,6 +109,7 @@
 #ifndef GOOGLE_PROTOBUF_IO_CODED_STREAM_H__
 #define GOOGLE_PROTOBUF_IO_CODED_STREAM_H__
 
+#include <assert.h>
 #include <string>
 #include <utility>
 #ifdef _MSC_VER
diff --git a/src/google/protobuf/io/strtod.cc b/src/google/protobuf/io/strtod.cc
index 579de9aa..a90bb9a3 100644
--- a/src/google/protobuf/io/strtod.cc
+++ b/src/google/protobuf/io/strtod.cc
@@ -32,6 +32,7 @@
 
 #include <cstdio>
 #include <cstring>
+#include <limits>
 #include <string>
 
 #include <google/protobuf/stubs/logging.h>
@@ -109,6 +110,16 @@ double NoLocaleStrtod(const char* text, char** original_endptr) {
   return result;
 }
 
+float SafeDoubleToFloat(double value) {
+  if (value > std::numeric_limits<float>::max()) {
+    return std::numeric_limits<float>::infinity();
+  } else if (value < -std::numeric_limits<float>::max()) {
+    return -std::numeric_limits<float>::infinity();
+  } else {
+    return static_cast<float>(value);
+  }
+}
+
 }  // namespace io
 }  // namespace protobuf
 }  // namespace google
diff --git a/src/google/protobuf/io/strtod.h b/src/google/protobuf/io/strtod.h
index c2efc8d3..f56e41c8 100644
--- a/src/google/protobuf/io/strtod.h
+++ b/src/google/protobuf/io/strtod.h
@@ -43,6 +43,11 @@ namespace io {
 // uses a dot as the decimal separator.
 double NoLocaleStrtod(const char* str, char** endptr);
 
+// Casts a double value to a float value. If the value is outside of the
+// representable range of float, it will be converted to positive or negative
+// infinity.
+float SafeDoubleToFloat(double value);
+
 }  // namespace io
 }  // namespace protobuf
 
diff --git a/src/google/protobuf/io/tokenizer.cc b/src/google/protobuf/io/tokenizer.cc
index 7ccd633d..3d57707c 100644
--- a/src/google/protobuf/io/tokenizer.cc
+++ b/src/google/protobuf/io/tokenizer.cc
@@ -375,7 +375,7 @@ void Tokenizer::ConsumeString(char delimiter) {
           // Possibly followed by two more octal digits, but these will
           // just be consumed by the main loop anyway so we don't need
           // to do so explicitly here.
-        } else if (TryConsume('x') || TryConsume('X')) {
+        } else if (TryConsume('x')) {
           if (!TryConsumeOne<HexDigit>()) {
             AddError("Expected hex digits for escape sequence.");
           }
diff --git a/src/google/protobuf/io/tokenizer_unittest.cc b/src/google/protobuf/io/tokenizer_unittest.cc
index 6526056a..20d50a2c 100644
--- a/src/google/protobuf/io/tokenizer_unittest.cc
+++ b/src/google/protobuf/io/tokenizer_unittest.cc
@@ -875,6 +875,8 @@ ErrorCase kErrorCases[] = {
   // String errors.
   { "'\\l' foo", true,
     "0:2: Invalid escape sequence in string literal.\n" },
+  { "'\\X' foo", true,
+    "0:2: Invalid escape sequence in string literal.\n" },
   { "'\\x' foo", true,
     "0:3: Expected hex digits for escape sequence.\n" },
   { "'foo", false,
diff --git a/src/google/protobuf/map.h b/src/google/protobuf/map.h
index 4bd76f25..dfc62420 100644
--- a/src/google/protobuf/map.h
+++ b/src/google/protobuf/map.h
@@ -188,7 +188,6 @@ class LIBPROTOBUF_EXPORT MapKey {
       case FieldDescriptor::CPPTYPE_ENUM:
       case FieldDescriptor::CPPTYPE_MESSAGE:
         GOOGLE_LOG(FATAL) << "Can't get here.";
-        return false;
     }
     GOOGLE_LOG(FATAL) << "Can't get here.";
     return false;
@@ -497,7 +496,7 @@ class Map {
     insert(other.begin(), other.end());
   }
   template <class InputIt>
-  explicit Map(const InputIt& first, const InputIt& last)
+  Map(const InputIt& first, const InputIt& last)
       : arena_(NULL),
         allocator_(arena_),
         elements_(0, hasher(), key_equal(), allocator_),
@@ -546,9 +545,7 @@ class Map {
     }
 
 #if __cplusplus >= 201103L && !defined(GOOGLE_PROTOBUF_OS_APPLE) && \
-    !defined(GOOGLE_PROTOBUF_OS_NACL) &&                            \
-    !defined(GOOGLE_PROTOBUF_OS_ANDROID) &&                         \
-    !defined(GOOGLE_PROTOBUF_OS_EMSCRIPTEN)
+    !defined(GOOGLE_PROTOBUF_OS_NACL) && !defined(GOOGLE_PROTOBUF_OS_ANDROID)
     template<class NodeType, class... Args>
     void construct(NodeType* p, Args&&... args) {
       new (static_cast<void*>(p)) NodeType(std::forward<Args>(args)...);
@@ -586,21 +583,22 @@ class Map {
 
    private:
     typedef void DestructorSkippable_;
-    Arena* arena_;
+    Arena* const arena_;
 
     template <typename X>
     friend class MapAllocator;
   };
 
- public:
   typedef MapAllocator<std::pair<const Key, MapPair<Key, T>*> > Allocator;
+  typedef hash_map<Key, value_type*, hash<Key>, equal_to<Key>, Allocator>
+      InnerMap;
 
+ public:
   // Iterators
   class const_iterator
       : public std::iterator<std::forward_iterator_tag, value_type, ptrdiff_t,
                              const value_type*, const value_type&> {
-    typedef typename hash_map<Key, value_type*, hash<Key>, equal_to<Key>,
-                              Allocator>::const_iterator InnerIt;
+    typedef typename InnerMap::const_iterator InnerIt;
 
    public:
     const_iterator() {}
@@ -627,8 +625,7 @@ class Map {
   };
 
   class iterator : public std::iterator<std::forward_iterator_tag, value_type> {
-    typedef typename hash_map<Key, value_type*, hasher, equal_to<Key>,
-                              Allocator>::iterator InnerIt;
+    typedef typename InnerMap::iterator InnerIt;
 
    public:
     iterator() {}
@@ -744,8 +741,7 @@ class Map {
 
   // Erase
   size_type erase(const key_type& key) {
-    typename hash_map<Key, value_type*, hash<Key>, equal_to<Key>,
-                      Allocator>::iterator it = elements_.find(key);
+    typename InnerMap::iterator it = elements_.find(key);
     if (it == elements_.end()) {
       return 0;
     } else {
@@ -815,7 +811,7 @@ class Map {
 
   Arena* arena_;
   Allocator allocator_;
-  hash_map<Key, value_type*, hash<Key>, equal_to<Key>, Allocator> elements_;
+  InnerMap elements_;
   int default_enum_value_;
 
   friend class ::google::protobuf::Arena;
@@ -854,7 +850,6 @@ struct hash<google::protobuf::MapKey> {
       case google::protobuf::FieldDescriptor::CPPTYPE_ENUM:
       case google::protobuf::FieldDescriptor::CPPTYPE_MESSAGE:
         GOOGLE_LOG(FATAL) << "Can't get here.";
-        return 0;
     }
     GOOGLE_LOG(FATAL) << "Can't get here.";
     return 0;
@@ -879,7 +874,6 @@ struct hash<google::protobuf::MapKey> {
       case google::protobuf::FieldDescriptor::CPPTYPE_ENUM:
       case google::protobuf::FieldDescriptor::CPPTYPE_MESSAGE:
         GOOGLE_LOG(FATAL) << "Can't get here.";
-        return true;
     }
     GOOGLE_LOG(FATAL) << "Can't get here.";
     return true;
diff --git a/src/google/protobuf/repeated_field.h b/src/google/protobuf/repeated_field.h
index 5530fefe..432236ce 100644
--- a/src/google/protobuf/repeated_field.h
+++ b/src/google/protobuf/repeated_field.h
@@ -208,10 +208,19 @@ class RepeatedField {
   // sizeof(*this)
   int SpaceUsedExcludingSelf() const;
 
-  // Remove the element referenced by position.
+  // Removes the element referenced by position.
+  //
+  // Returns an iterator to the element immediately following the removed
+  // element.
+  //
+  // Invalidates all iterators at or after the removed element, including end().
   iterator erase(const_iterator position);
 
-  // Remove the elements in the range [first, last).
+  // Removes the elements in the range [first, last).
+  //
+  // Returns an iterator to the element immediately following the removed range.
+  //
+  // Invalidates all iterators at or after the removed range, including end().
   iterator erase(const_iterator first, const_iterator last);
 
   // Get the Arena on which this RepeatedField stores its elements.
@@ -885,10 +894,19 @@ class RepeatedPtrField : public internal::RepeatedPtrFieldBase {
   // so will trigger a GOOGLE_DCHECK-failure.
   Element* ReleaseCleared();
 
-  // Remove the element referenced by position.
+  // Removes the element referenced by position.
+  //
+  // Returns an iterator to the element immediately following the removed
+  // element.
+  //
+  // Invalidates all iterators at or after the removed element, including end().
   iterator erase(const_iterator position);
 
   // Removes the elements in the range [first, last).
+  //
+  // Returns an iterator to the element immediately following the removed range.
+  //
+  // Invalidates all iterators at or after the removed range, including end().
   iterator erase(const_iterator first, const_iterator last);
 
   // Gets the arena on which this RepeatedPtrField stores its elements.
diff --git a/src/google/protobuf/source_context.pb.cc b/src/google/protobuf/source_context.pb.cc
index 1be3297e..f2eb7ae7 100644
--- a/src/google/protobuf/source_context.pb.cc
+++ b/src/google/protobuf/source_context.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
diff --git a/src/google/protobuf/source_context.proto b/src/google/protobuf/source_context.proto
index e9a27d65..d76252ca 100644
--- a/src/google/protobuf/source_context.proto
+++ b/src/google/protobuf/source_context.proto
@@ -27,15 +27,16 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
 package google.protobuf;
 
-option java_multiple_files = true;
-option java_outer_classname = "SourceContextProto";
+option csharp_namespace = "Google.Protobuf.WellKnownTypes";
 option java_package = "com.google.protobuf";
+option java_outer_classname = "SourceContextProto";
+option java_multiple_files = true;
 option java_generate_equals_and_hash = true;
-option csharp_namespace = "Google.Protobuf.WellKnownTypes";
 option objc_class_prefix = "GPB";
 
 // `SourceContext` represents information about the source of a
diff --git a/src/google/protobuf/struct.pb.cc b/src/google/protobuf/struct.pb.cc
index 273645d9..e020597a 100644
--- a/src/google/protobuf/struct.pb.cc
+++ b/src/google/protobuf/struct.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
diff --git a/src/google/protobuf/struct.proto b/src/google/protobuf/struct.proto
index b3e9e699..8562e2c1 100644
--- a/src/google/protobuf/struct.proto
+++ b/src/google/protobuf/struct.proto
@@ -27,15 +27,16 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
 package google.protobuf;
 
-option java_generate_equals_and_hash = true;
-option java_multiple_files = true;
-option java_outer_classname = "StructProto";
-option java_package = "com.google.protobuf";
 option csharp_namespace = "Google.Protobuf.WellKnownTypes";
+option java_package = "com.google.protobuf";
+option java_outer_classname = "StructProto";
+option java_multiple_files = true;
+option java_generate_equals_and_hash = true;
 option objc_class_prefix = "GPB";
 
 
diff --git a/src/google/protobuf/stubs/strutil.cc b/src/google/protobuf/stubs/strutil.cc
index 8442f2ce..7ba92e8f 100644
--- a/src/google/protobuf/stubs/strutil.cc
+++ b/src/google/protobuf/stubs/strutil.cc
@@ -524,27 +524,81 @@ int CEscapeInternal(const char* src, int src_len, char* dest,
   return used;
 }
 
-int CEscapeString(const char* src, int src_len, char* dest, int dest_len) {
-  return CEscapeInternal(src, src_len, dest, dest_len, false, false);
+// Calculates the length of the C-style escaped version of 'src'.
+// Assumes that non-printable characters are escaped using octal sequences, and
+// that UTF-8 bytes are not handled specially.
+static inline size_t CEscapedLength(StringPiece src) {
+  static char c_escaped_len[256] = {
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 2, 2, 4, 4, 2, 4, 4,  // \t, \n, \r
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+    1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1,  // ", '
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // '0'..'9'
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 'A'..'O'
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1,  // 'P'..'Z', '\'
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 'a'..'o'
+    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4,  // 'p'..'z', DEL
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+    4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+  };
+
+  size_t escaped_len = 0;
+  for (int i = 0; i < src.size(); ++i) {
+    unsigned char c = static_cast<unsigned char>(src[i]);
+    escaped_len += c_escaped_len[c];
+  }
+  return escaped_len;
 }
 
 // ----------------------------------------------------------------------
-// CEscape()
-// CHexEscape()
-//    Copies 'src' to result, escaping dangerous characters using
-//    C-style escape sequences. This is very useful for preparing query
-//    flags. 'src' and 'dest' should not overlap. The 'Hex' version
-//    hexadecimal rather than octal sequences.
-//
-//    Currently only \n, \r, \t, ", ', \ and !isprint() chars are escaped.
+// Escapes 'src' using C-style escape sequences, and appends the escaped string
+// to 'dest'. This version is faster than calling CEscapeInternal as it computes
+// the required space using a lookup table, and also does not do any special
+// handling for Hex or UTF-8 characters.
 // ----------------------------------------------------------------------
+void CEscapeAndAppend(StringPiece src, string* dest) {
+  size_t escaped_len = CEscapedLength(src);
+  if (escaped_len == src.size()) {
+    dest->append(src.data(), src.size());
+    return;
+  }
+
+  size_t cur_dest_len = dest->size();
+  dest->resize(cur_dest_len + escaped_len);
+  char* append_ptr = &(*dest)[cur_dest_len];
+
+  for (int i = 0; i < src.size(); ++i) {
+    unsigned char c = static_cast<unsigned char>(src[i]);
+    switch (c) {
+      case '\n': *append_ptr++ = '\\'; *append_ptr++ = 'n'; break;
+      case '\r': *append_ptr++ = '\\'; *append_ptr++ = 'r'; break;
+      case '\t': *append_ptr++ = '\\'; *append_ptr++ = 't'; break;
+      case '\"': *append_ptr++ = '\\'; *append_ptr++ = '\"'; break;
+      case '\'': *append_ptr++ = '\\'; *append_ptr++ = '\''; break;
+      case '\\': *append_ptr++ = '\\'; *append_ptr++ = '\\'; break;
+      default:
+        if (!isprint(c)) {
+          *append_ptr++ = '\\';
+          *append_ptr++ = '0' + c / 64;
+          *append_ptr++ = '0' + (c % 64) / 8;
+          *append_ptr++ = '0' + c % 8;
+        } else {
+          *append_ptr++ = c;
+        }
+        break;
+    }
+  }
+}
+
 string CEscape(const string& src) {
-  const int dest_length = src.size() * 4 + 1; // Maximum possible expansion
-  scoped_array<char> dest(new char[dest_length]);
-  const int len = CEscapeInternal(src.data(), src.size(),
-                                  dest.get(), dest_length, false, false);
-  GOOGLE_DCHECK_GE(len, 0);
-  return string(dest.get(), len);
+  string dest;
+  CEscapeAndAppend(src, &dest);
+  return dest;
 }
 
 namespace strings {
diff --git a/src/google/protobuf/stubs/strutil.h b/src/google/protobuf/stubs/strutil.h
index b22066b6..27d47575 100644
--- a/src/google/protobuf/stubs/strutil.h
+++ b/src/google/protobuf/stubs/strutil.h
@@ -314,26 +314,20 @@ LIBPROTOBUF_EXPORT int UnescapeCEscapeString(const string& src, string* dest,
 LIBPROTOBUF_EXPORT string UnescapeCEscapeString(const string& src);
 
 // ----------------------------------------------------------------------
-// CEscapeString()
-//    Copies 'src' to 'dest', escaping dangerous characters using
-//    C-style escape sequences. This is very useful for preparing query
-//    flags. 'src' and 'dest' should not overlap.
-//    Returns the number of bytes written to 'dest' (not including the \0)
-//    or -1 if there was insufficient space.
+// CEscape()
+//    Escapes 'src' using C-style escape sequences and returns the resulting
+//    string.
 //
-//    Currently only \n, \r, \t, ", ', \ and !isprint() chars are escaped.
+//    Escaped chars: \n, \r, \t, ", ', \, and !isprint().
 // ----------------------------------------------------------------------
-LIBPROTOBUF_EXPORT int CEscapeString(const char* src, int src_len,
-                                     char* dest, int dest_len);
+LIBPROTOBUF_EXPORT string CEscape(const string& src);
 
 // ----------------------------------------------------------------------
-// CEscape()
-//    More convenient form of CEscapeString: returns result as a "string".
-//    This version is slower than CEscapeString() because it does more
-//    allocation.  However, it is much more convenient to use in
-//    non-speed-critical code like logging messages etc.
+// CEscapeAndAppend()
+//    Escapes 'src' using C-style escape sequences, and appends the escaped
+//    string to 'dest'.
 // ----------------------------------------------------------------------
-LIBPROTOBUF_EXPORT string CEscape(const string& src);
+LIBPROTOBUF_EXPORT void CEscapeAndAppend(StringPiece src, string* dest);
 
 namespace strings {
 // Like CEscape() but does not escape bytes with the upper bit set.
diff --git a/src/google/protobuf/text_format.cc b/src/google/protobuf/text_format.cc
index 38b9069b..b0a5ce63 100644
--- a/src/google/protobuf/text_format.cc
+++ b/src/google/protobuf/text_format.cc
@@ -46,6 +46,7 @@
 #include <google/protobuf/dynamic_message.h>
 #include <google/protobuf/repeated_field.h>
 #include <google/protobuf/wire_format_lite.h>
+#include <google/protobuf/io/strtod.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
@@ -380,6 +381,7 @@ class TextFormat::Parser::ParserImpl {
       string full_type_name, prefix;
       DO(ConsumeAnyTypeUrl(&full_type_name, &prefix));
       DO(Consume("]"));
+      TryConsume(":");  // ':' is optional between message labels and values.
       string serialized_value;
       DO(ConsumeAnyValue(full_type_name,
                          message->GetDescriptor()->file()->pool(),
@@ -389,7 +391,6 @@ class TextFormat::Parser::ParserImpl {
           string(prefix + full_type_name));
       reflection->SetString(message, any_value_field, serialized_value);
       return true;
-      // Fall through.
     }
     if (TryConsume("[")) {
       // Extension.
@@ -656,7 +657,7 @@ class TextFormat::Parser::ParserImpl {
       case FieldDescriptor::CPPTYPE_FLOAT: {
         double value;
         DO(ConsumeDouble(&value));
-        SET_FIELD(Float, static_cast<float>(value));
+        SET_FIELD(Float, io::SafeDoubleToFloat(value));
         break;
       }
 
@@ -1357,7 +1358,10 @@ string TextFormat::FieldValuePrinter::PrintDouble(double val) const {
   return SimpleDtoa(val);
 }
 string TextFormat::FieldValuePrinter::PrintString(const string& val) const {
-  return StrCat("\"", CEscape(val), "\"");
+  string printed("\"");
+  CEscapeAndAppend(val, &printed);
+  printed.push_back('\"');
+  return printed;
 }
 string TextFormat::FieldValuePrinter::PrintBytes(const string& val) const {
   return PrintString(val);
@@ -1423,7 +1427,8 @@ TextFormat::Printer::Printer()
     use_short_repeated_primitives_(false),
     hide_unknown_fields_(false),
     print_message_fields_in_index_order_(false),
-    expand_any_(false) {
+    expand_any_(false),
+    truncate_string_field_longer_than_(0LL) {
   SetUseUtf8StringEscaping(false);
 }
 
@@ -1775,11 +1780,21 @@ void TextFormat::Printer::PrintFieldValue(
           ? reflection->GetRepeatedStringReference(
               message, field, index, &scratch)
           : reflection->GetStringReference(message, field, &scratch);
+      int64 size = value.size();
+      if (truncate_string_field_longer_than_ > 0) {
+        size = std::min(truncate_string_field_longer_than_,
+                        static_cast<int64>(value.size()));
+      }
+      string truncated_value(value.substr(0, size) + "...<truncated>...");
+      const string* value_to_print = &value;
+      if (size < value.size()) {
+        value_to_print = &truncated_value;
+      }
       if (field->type() == FieldDescriptor::TYPE_STRING) {
-        generator.Print(printer->PrintString(value));
+        generator.Print(printer->PrintString(*value_to_print));
       } else {
         GOOGLE_DCHECK_EQ(field->type(), FieldDescriptor::TYPE_BYTES);
-        generator.Print(printer->PrintBytes(value));
+        generator.Print(printer->PrintBytes(*value_to_print));
       }
       break;
     }
@@ -1926,14 +1941,10 @@ void TextFormat::Printer::PrintUnknownFields(
         } else {
           // This field is not parseable as a Message.
           // So it is probably just a plain string.
-          generator.Print(": \"");
-          generator.Print(CEscape(value));
-          generator.Print("\"");
-          if (single_line_mode_) {
-            generator.Print(" ");
-          } else {
-            generator.Print("\n");
-          }
+          string printed(": \"");
+          CEscapeAndAppend(value, &printed);
+          printed.append(single_line_mode_ ? "\" " : "\"\n");
+          generator.Print(printed);
         }
         break;
       }
diff --git a/src/google/protobuf/text_format.h b/src/google/protobuf/text_format.h
index 6717aecd..ef3d4a8f 100644
--- a/src/google/protobuf/text_format.h
+++ b/src/google/protobuf/text_format.h
@@ -219,6 +219,18 @@ class LIBPROTOBUF_EXPORT TextFormat {
       expand_any_ = expand;
     }
 
+    // If non-zero, we truncate all string fields that are  longer than this
+    // threshold.  This is useful when the proto message has very long strings,
+    // e.g., dump of encoded image file.
+    //
+    // NOTE(hfgong):  Setting a non-zero value breaks round-trip safe
+    // property of TextFormat::Printer.  That is, from the printed message, we
+    // cannot fully recover the original string field any more.
+    void SetTruncateStringFieldLongerThan(
+        const int64 truncate_string_field_longer_than) {
+      truncate_string_field_longer_than_ = truncate_string_field_longer_than;
+    }
+
     // Register a custom field-specific FieldValuePrinter for fields
     // with a particular FieldDescriptor.
     // Returns "true" if the registration succeeded, or "false", if there is
@@ -286,6 +298,8 @@ class LIBPROTOBUF_EXPORT TextFormat {
 
     bool expand_any_;
 
+    int64 truncate_string_field_longer_than_;
+
     google::protobuf::scoped_ptr<const FieldValuePrinter> default_field_value_printer_;
     typedef map<const FieldDescriptor*,
                 const FieldValuePrinter*> CustomPrinterMap;
diff --git a/src/google/protobuf/timestamp.pb.cc b/src/google/protobuf/timestamp.pb.cc
index f0b09195..c1c4402c 100644
--- a/src/google/protobuf/timestamp.pb.cc
+++ b/src/google/protobuf/timestamp.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
@@ -82,9 +83,9 @@ void protobuf_AddDesc_google_2fprotobuf_2ftimestamp_2eproto() {
   ::google::protobuf::DescriptorPool::InternalAddGeneratedFile(
     "\n\037google/protobuf/timestamp.proto\022\017googl"
     "e.protobuf\"+\n\tTimestamp\022\017\n\007seconds\030\001 \001(\003"
-    "\022\r\n\005nanos\030\002 \001(\005BQ\n\023com.google.protobufB\016"
-    "TimestampProtoP\001\240\001\001\242\002\003GPB\252\002\036Google.Proto"
-    "buf.WellKnownTypesb\006proto3", 186);
+    "\022\r\n\005nanos\030\002 \001(\005BT\n\023com.google.protobufB\016"
+    "TimestampProtoP\001\240\001\001\370\001\001\242\002\003GPB\252\002\036Google.Pr"
+    "otobuf.WellKnownTypesb\006proto3", 189);
   ::google::protobuf::MessageFactory::InternalRegisterGeneratedFile(
     "google/protobuf/timestamp.proto", &protobuf_RegisterTypes);
   Timestamp::default_instance_ = new Timestamp();
@@ -122,6 +123,14 @@ Timestamp::Timestamp()
   // @@protoc_insertion_point(constructor:google.protobuf.Timestamp)
 }
 
+Timestamp::Timestamp(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.Timestamp)
+}
+
 void Timestamp::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -147,10 +156,20 @@ Timestamp::~Timestamp() {
 }
 
 void Timestamp::SharedDtor() {
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
   if (this != default_instance_) {
   }
 }
 
+void Timestamp::ArenaDtor(void* object) {
+  Timestamp* _this = reinterpret_cast< Timestamp* >(object);
+  (void)_this;
+}
+void Timestamp::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void Timestamp::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -169,11 +188,7 @@ const Timestamp& Timestamp::default_instance() {
 Timestamp* Timestamp::default_instance_ = NULL;
 
 Timestamp* Timestamp::New(::google::protobuf::Arena* arena) const {
-  Timestamp* n = new Timestamp;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<Timestamp>(arena);
 }
 
 void Timestamp::Clear() {
@@ -349,6 +364,18 @@ bool Timestamp::IsInitialized() const {
 
 void Timestamp::Swap(Timestamp* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    Timestamp temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void Timestamp::UnsafeArenaSwap(Timestamp* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void Timestamp::InternalSwap(Timestamp* other) {
diff --git a/src/google/protobuf/timestamp.pb.h b/src/google/protobuf/timestamp.pb.h
index 85fc1242..7bf62597 100644
--- a/src/google/protobuf/timestamp.pb.h
+++ b/src/google/protobuf/timestamp.pb.h
@@ -53,9 +53,14 @@ class LIBPROTOBUF_EXPORT Timestamp : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const Timestamp& default_instance();
 
+  void UnsafeArenaSwap(Timestamp* other);
   void Swap(Timestamp* other);
 
   // implements Message ----------------------------------------------
@@ -82,6 +87,11 @@ class LIBPROTOBUF_EXPORT Timestamp : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(Timestamp* other);
+  protected:
+  explicit Timestamp(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -113,6 +123,9 @@ class LIBPROTOBUF_EXPORT Timestamp : public ::google::protobuf::Message {
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   ::google::protobuf::int64 seconds_;
   ::google::protobuf::int32 nanos_;
diff --git a/src/google/protobuf/timestamp.proto b/src/google/protobuf/timestamp.proto
index 06b60e6f..b51fc3fa 100644
--- a/src/google/protobuf/timestamp.proto
+++ b/src/google/protobuf/timestamp.proto
@@ -27,15 +27,17 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
 package google.protobuf;
 
-option java_generate_equals_and_hash = true;
-option java_multiple_files = true;
-option java_outer_classname = "TimestampProto";
-option java_package = "com.google.protobuf";
 option csharp_namespace = "Google.Protobuf.WellKnownTypes";
+option cc_enable_arenas = true;
+option java_package = "com.google.protobuf";
+option java_outer_classname = "TimestampProto";
+option java_multiple_files = true;
+option java_generate_equals_and_hash = true;
 option objc_class_prefix = "GPB";
 
 // A Timestamp represents a point in time independent of any time zone
@@ -92,6 +94,7 @@ option objc_class_prefix = "GPB";
 //     nanos = int((now - seconds) * 10**9)
 //     timestamp = Timestamp(seconds=seconds, nanos=nanos)
 //
+//
 message Timestamp {
 
   // Represents seconds of UTC time since Unix epoch
diff --git a/src/google/protobuf/type.pb.cc b/src/google/protobuf/type.pb.cc
index 5792dff2..7b47b3bd 100644
--- a/src/google/protobuf/type.pb.cc
+++ b/src/google/protobuf/type.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
@@ -70,7 +71,7 @@ void protobuf_AssignDesc_google_2fprotobuf_2ftype_2eproto() {
       GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(Type, _internal_metadata_),
       GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(Type, _is_default_instance_));
   Field_descriptor_ = file->message_type(1);
-  static const int Field_offsets_[9] = {
+  static const int Field_offsets_[10] = {
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(Field, kind_),
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(Field, cardinality_),
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(Field, number_),
@@ -80,6 +81,7 @@ void protobuf_AssignDesc_google_2fprotobuf_2ftype_2eproto() {
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(Field, packed_),
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(Field, options_),
     GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(Field, json_name_),
+    GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(Field, default_value_),
   };
   Field_reflection_ =
     ::google::protobuf::internal::GeneratedMessageReflection::NewGeneratedMessageReflection(
@@ -203,37 +205,37 @@ void protobuf_AddDesc_google_2fprotobuf_2ftype_2eproto() {
     "\030\004 \003(\0132\027.google.protobuf.Option\0226\n\016sourc"
     "e_context\030\005 \001(\0132\036.google.protobuf.Source"
     "Context\022\'\n\006syntax\030\006 \001(\0162\027.google.protobu"
-    "f.Syntax\"\276\005\n\005Field\022)\n\004kind\030\001 \001(\0162\033.googl"
+    "f.Syntax\"\325\005\n\005Field\022)\n\004kind\030\001 \001(\0162\033.googl"
     "e.protobuf.Field.Kind\0227\n\013cardinality\030\002 \001"
     "(\0162\".google.protobuf.Field.Cardinality\022\016"
     "\n\006number\030\003 \001(\005\022\014\n\004name\030\004 \001(\t\022\020\n\010type_url"
     "\030\006 \001(\t\022\023\n\013oneof_index\030\007 \001(\005\022\016\n\006packed\030\010 "
     "\001(\010\022(\n\007options\030\t \003(\0132\027.google.protobuf.O"
-    "ption\022\021\n\tjson_name\030\n \001(\t\"\310\002\n\004Kind\022\020\n\014TYP"
-    "E_UNKNOWN\020\000\022\017\n\013TYPE_DOUBLE\020\001\022\016\n\nTYPE_FLO"
-    "AT\020\002\022\016\n\nTYPE_INT64\020\003\022\017\n\013TYPE_UINT64\020\004\022\016\n"
-    "\nTYPE_INT32\020\005\022\020\n\014TYPE_FIXED64\020\006\022\020\n\014TYPE_"
-    "FIXED32\020\007\022\r\n\tTYPE_BOOL\020\010\022\017\n\013TYPE_STRING\020"
-    "\t\022\016\n\nTYPE_GROUP\020\n\022\020\n\014TYPE_MESSAGE\020\013\022\016\n\nT"
-    "YPE_BYTES\020\014\022\017\n\013TYPE_UINT32\020\r\022\r\n\tTYPE_ENU"
-    "M\020\016\022\021\n\rTYPE_SFIXED32\020\017\022\021\n\rTYPE_SFIXED64\020"
-    "\020\022\017\n\013TYPE_SINT32\020\021\022\017\n\013TYPE_SINT64\020\022\"t\n\013C"
-    "ardinality\022\027\n\023CARDINALITY_UNKNOWN\020\000\022\030\n\024C"
-    "ARDINALITY_OPTIONAL\020\001\022\030\n\024CARDINALITY_REQ"
-    "UIRED\020\002\022\030\n\024CARDINALITY_REPEATED\020\003\"\316\001\n\004En"
-    "um\022\014\n\004name\030\001 \001(\t\022-\n\tenumvalue\030\002 \003(\0132\032.go"
-    "ogle.protobuf.EnumValue\022(\n\007options\030\003 \003(\013"
-    "2\027.google.protobuf.Option\0226\n\016source_cont"
-    "ext\030\004 \001(\0132\036.google.protobuf.SourceContex"
-    "t\022\'\n\006syntax\030\005 \001(\0162\027.google.protobuf.Synt"
-    "ax\"S\n\tEnumValue\022\014\n\004name\030\001 \001(\t\022\016\n\006number\030"
-    "\002 \001(\005\022(\n\007options\030\003 \003(\0132\027.google.protobuf"
-    ".Option\";\n\006Option\022\014\n\004name\030\001 \001(\t\022#\n\005value"
-    "\030\002 \001(\0132\024.google.protobuf.Any*.\n\006Syntax\022\021"
-    "\n\rSYNTAX_PROTO2\020\000\022\021\n\rSYNTAX_PROTO3\020\001BL\n\023"
-    "com.google.protobufB\tTypeProtoP\001\240\001\001\242\002\003GP"
-    "B\252\002\036Google.Protobuf.WellKnownTypesb\006prot"
-    "o3", 1522);
+    "ption\022\021\n\tjson_name\030\n \001(\t\022\025\n\rdefault_valu"
+    "e\030\013 \001(\t\"\310\002\n\004Kind\022\020\n\014TYPE_UNKNOWN\020\000\022\017\n\013TY"
+    "PE_DOUBLE\020\001\022\016\n\nTYPE_FLOAT\020\002\022\016\n\nTYPE_INT6"
+    "4\020\003\022\017\n\013TYPE_UINT64\020\004\022\016\n\nTYPE_INT32\020\005\022\020\n\014"
+    "TYPE_FIXED64\020\006\022\020\n\014TYPE_FIXED32\020\007\022\r\n\tTYPE"
+    "_BOOL\020\010\022\017\n\013TYPE_STRING\020\t\022\016\n\nTYPE_GROUP\020\n"
+    "\022\020\n\014TYPE_MESSAGE\020\013\022\016\n\nTYPE_BYTES\020\014\022\017\n\013TY"
+    "PE_UINT32\020\r\022\r\n\tTYPE_ENUM\020\016\022\021\n\rTYPE_SFIXE"
+    "D32\020\017\022\021\n\rTYPE_SFIXED64\020\020\022\017\n\013TYPE_SINT32\020"
+    "\021\022\017\n\013TYPE_SINT64\020\022\"t\n\013Cardinality\022\027\n\023CAR"
+    "DINALITY_UNKNOWN\020\000\022\030\n\024CARDINALITY_OPTION"
+    "AL\020\001\022\030\n\024CARDINALITY_REQUIRED\020\002\022\030\n\024CARDIN"
+    "ALITY_REPEATED\020\003\"\316\001\n\004Enum\022\014\n\004name\030\001 \001(\t\022"
+    "-\n\tenumvalue\030\002 \003(\0132\032.google.protobuf.Enu"
+    "mValue\022(\n\007options\030\003 \003(\0132\027.google.protobu"
+    "f.Option\0226\n\016source_context\030\004 \001(\0132\036.googl"
+    "e.protobuf.SourceContext\022\'\n\006syntax\030\005 \001(\016"
+    "2\027.google.protobuf.Syntax\"S\n\tEnumValue\022\014"
+    "\n\004name\030\001 \001(\t\022\016\n\006number\030\002 \001(\005\022(\n\007options\030"
+    "\003 \003(\0132\027.google.protobuf.Option\";\n\006Option"
+    "\022\014\n\004name\030\001 \001(\t\022#\n\005value\030\002 \001(\0132\024.google.p"
+    "rotobuf.Any*.\n\006Syntax\022\021\n\rSYNTAX_PROTO2\020\000"
+    "\022\021\n\rSYNTAX_PROTO3\020\001BL\n\023com.google.protob"
+    "ufB\tTypeProtoP\001\240\001\001\242\002\003GPB\252\002\036Google.Protob"
+    "uf.WellKnownTypesb\006proto3", 1545);
   ::google::protobuf::MessageFactory::InternalRegisterGeneratedFile(
     "google/protobuf/type.proto", &protobuf_RegisterTypes);
   Type::default_instance_ = new Type();
@@ -1026,6 +1028,7 @@ const int Field::kOneofIndexFieldNumber;
 const int Field::kPackedFieldNumber;
 const int Field::kOptionsFieldNumber;
 const int Field::kJsonNameFieldNumber;
+const int Field::kDefaultValueFieldNumber;
 #endif  // !defined(_MSC_VER) || _MSC_VER >= 1900
 
 Field::Field()
@@ -1058,6 +1061,7 @@ void Field::SharedCtor() {
   oneof_index_ = 0;
   packed_ = false;
   json_name_.UnsafeSetDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  default_value_.UnsafeSetDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 
 Field::~Field() {
@@ -1069,6 +1073,7 @@ void Field::SharedDtor() {
   name_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   type_url_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   json_name_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  default_value_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   if (this != default_instance_) {
   }
 }
@@ -1113,6 +1118,7 @@ void Field::Clear() {
   type_url_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   packed_ = false;
   json_name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  default_value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 
 #undef ZR_HELPER_
 #undef ZR_
@@ -1270,6 +1276,23 @@ bool Field::MergePartialFromCodedStream(
         } else {
           goto handle_unusual;
         }
+        if (input->ExpectTag(90)) goto parse_default_value;
+        break;
+      }
+
+      // optional string default_value = 11;
+      case 11: {
+        if (tag == 90) {
+         parse_default_value:
+          DO_(::google::protobuf::internal::WireFormatLite::ReadString(
+                input, this->mutable_default_value()));
+          DO_(::google::protobuf::internal::WireFormatLite::VerifyUtf8String(
+            this->default_value().data(), this->default_value().length(),
+            ::google::protobuf::internal::WireFormatLite::PARSE,
+            "google.protobuf.Field.default_value"));
+        } else {
+          goto handle_unusual;
+        }
         if (input->ExpectAtEnd()) goto success;
         break;
       }
@@ -1361,6 +1384,16 @@ void Field::SerializeWithCachedSizes(
       10, this->json_name(), output);
   }
 
+  // optional string default_value = 11;
+  if (this->default_value().size() > 0) {
+    ::google::protobuf::internal::WireFormatLite::VerifyUtf8String(
+      this->default_value().data(), this->default_value().length(),
+      ::google::protobuf::internal::WireFormatLite::SERIALIZE,
+      "google.protobuf.Field.default_value");
+    ::google::protobuf::internal::WireFormatLite::WriteStringMaybeAliased(
+      11, this->default_value(), output);
+  }
+
   // @@protoc_insertion_point(serialize_end:google.protobuf.Field)
 }
 
@@ -1434,6 +1467,17 @@ void Field::SerializeWithCachedSizes(
         10, this->json_name(), target);
   }
 
+  // optional string default_value = 11;
+  if (this->default_value().size() > 0) {
+    ::google::protobuf::internal::WireFormatLite::VerifyUtf8String(
+      this->default_value().data(), this->default_value().length(),
+      ::google::protobuf::internal::WireFormatLite::SERIALIZE,
+      "google.protobuf.Field.default_value");
+    target =
+      ::google::protobuf::internal::WireFormatLite::WriteStringToArray(
+        11, this->default_value(), target);
+  }
+
   // @@protoc_insertion_point(serialize_to_array_end:google.protobuf.Field)
   return target;
 }
@@ -1493,6 +1537,13 @@ int Field::ByteSize() const {
         this->json_name());
   }
 
+  // optional string default_value = 11;
+  if (this->default_value().size() > 0) {
+    total_size += 1 +
+      ::google::protobuf::internal::WireFormatLite::StringSize(
+        this->default_value());
+  }
+
   // repeated .google.protobuf.Option options = 9;
   total_size += 1 * this->options_size();
   for (int i = 0; i < this->options_size(); i++) {
@@ -1549,6 +1600,10 @@ void Field::MergeFrom(const Field& from) {
 
     json_name_.AssignWithDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), from.json_name_);
   }
+  if (from.default_value().size() > 0) {
+
+    default_value_.AssignWithDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), from.default_value_);
+  }
 }
 
 void Field::CopyFrom(const ::google::protobuf::Message& from) {
@@ -1582,6 +1637,7 @@ void Field::InternalSwap(Field* other) {
   std::swap(packed_, other->packed_);
   options_.UnsafeArenaSwap(&other->options_);
   json_name_.Swap(&other->json_name_);
+  default_value_.Swap(&other->default_value_);
   _internal_metadata_.Swap(&other->_internal_metadata_);
   std::swap(_cached_size_, other->_cached_size_);
 }
@@ -1826,6 +1882,49 @@ void Field::clear_json_name() {
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Field.json_name)
 }
 
+// optional string default_value = 11;
+void Field::clear_default_value() {
+  default_value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+ const ::std::string& Field::default_value() const {
+  // @@protoc_insertion_point(field_get:google.protobuf.Field.default_value)
+  return default_value_.GetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+ void Field::set_default_value(const ::std::string& value) {
+  
+  default_value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  // @@protoc_insertion_point(field_set:google.protobuf.Field.default_value)
+}
+ void Field::set_default_value(const char* value) {
+  
+  default_value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value));
+  // @@protoc_insertion_point(field_set_char:google.protobuf.Field.default_value)
+}
+ void Field::set_default_value(const char* value, size_t size) {
+  
+  default_value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      ::std::string(reinterpret_cast<const char*>(value), size));
+  // @@protoc_insertion_point(field_set_pointer:google.protobuf.Field.default_value)
+}
+ ::std::string* Field::mutable_default_value() {
+  
+  // @@protoc_insertion_point(field_mutable:google.protobuf.Field.default_value)
+  return default_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+ ::std::string* Field::release_default_value() {
+  
+  return default_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+ void Field::set_allocated_default_value(::std::string* default_value) {
+  if (default_value != NULL) {
+    
+  } else {
+    
+  }
+  default_value_.SetAllocatedNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), default_value);
+  // @@protoc_insertion_point(field_set_allocated:google.protobuf.Field.default_value)
+}
+
 #endif  // PROTOBUF_INLINE_NOT_IN_HEADERS
 
 // ===================================================================
diff --git a/src/google/protobuf/type.pb.h b/src/google/protobuf/type.pb.h
index 2533eb4e..76fe8a65 100644
--- a/src/google/protobuf/type.pb.h
+++ b/src/google/protobuf/type.pb.h
@@ -471,6 +471,17 @@ class LIBPROTOBUF_EXPORT Field : public ::google::protobuf::Message {
   ::std::string* release_json_name();
   void set_allocated_json_name(::std::string* json_name);
 
+  // optional string default_value = 11;
+  void clear_default_value();
+  static const int kDefaultValueFieldNumber = 11;
+  const ::std::string& default_value() const;
+  void set_default_value(const ::std::string& value);
+  void set_default_value(const char* value);
+  void set_default_value(const char* value, size_t size);
+  ::std::string* mutable_default_value();
+  ::std::string* release_default_value();
+  void set_allocated_default_value(::std::string* default_value);
+
   // @@protoc_insertion_point(class_scope:google.protobuf.Field)
  private:
 
@@ -484,6 +495,7 @@ class LIBPROTOBUF_EXPORT Field : public ::google::protobuf::Message {
   ::google::protobuf::internal::ArenaStringPtr type_url_;
   ::google::protobuf::RepeatedPtrField< ::google::protobuf::Option > options_;
   ::google::protobuf::internal::ArenaStringPtr json_name_;
+  ::google::protobuf::internal::ArenaStringPtr default_value_;
   bool packed_;
   mutable int _cached_size_;
   friend void LIBPROTOBUF_EXPORT protobuf_AddDesc_google_2fprotobuf_2ftype_2eproto();
@@ -1264,6 +1276,49 @@ inline void Field::set_allocated_json_name(::std::string* json_name) {
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Field.json_name)
 }
 
+// optional string default_value = 11;
+inline void Field::clear_default_value() {
+  default_value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+inline const ::std::string& Field::default_value() const {
+  // @@protoc_insertion_point(field_get:google.protobuf.Field.default_value)
+  return default_value_.GetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+inline void Field::set_default_value(const ::std::string& value) {
+  
+  default_value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  // @@protoc_insertion_point(field_set:google.protobuf.Field.default_value)
+}
+inline void Field::set_default_value(const char* value) {
+  
+  default_value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value));
+  // @@protoc_insertion_point(field_set_char:google.protobuf.Field.default_value)
+}
+inline void Field::set_default_value(const char* value, size_t size) {
+  
+  default_value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      ::std::string(reinterpret_cast<const char*>(value), size));
+  // @@protoc_insertion_point(field_set_pointer:google.protobuf.Field.default_value)
+}
+inline ::std::string* Field::mutable_default_value() {
+  
+  // @@protoc_insertion_point(field_mutable:google.protobuf.Field.default_value)
+  return default_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+inline ::std::string* Field::release_default_value() {
+  
+  return default_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+}
+inline void Field::set_allocated_default_value(::std::string* default_value) {
+  if (default_value != NULL) {
+    
+  } else {
+    
+  }
+  default_value_.SetAllocatedNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), default_value);
+  // @@protoc_insertion_point(field_set_allocated:google.protobuf.Field.default_value)
+}
+
 // -------------------------------------------------------------------
 
 // Enum
diff --git a/src/google/protobuf/type.proto b/src/google/protobuf/type.proto
index 4df95762..1c9cf53d 100644
--- a/src/google/protobuf/type.proto
+++ b/src/google/protobuf/type.proto
@@ -27,6 +27,7 @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 syntax = "proto3";
 
 package google.protobuf;
@@ -34,22 +35,22 @@ package google.protobuf;
 import "google/protobuf/any.proto";
 import "google/protobuf/source_context.proto";
 
+option csharp_namespace = "Google.Protobuf.WellKnownTypes";
 option java_package = "com.google.protobuf";
 option java_outer_classname = "TypeProto";
 option java_multiple_files = true;
 option java_generate_equals_and_hash = true;
-option csharp_namespace = "Google.Protobuf.WellKnownTypes";
 option objc_class_prefix = "GPB";
 
-// A light-weight descriptor for a proto message type.
+// A protocol buffer message type.
 message Type {
   // The fully qualified message name.
   string name = 1;
   // The list of fields.
   repeated Field fields = 2;
-  // The list of oneof definitions.
-  repeated string oneofs = 3;  // The list of oneofs declared in this Type
-  // The proto options.
+  // The list of types appearing in `oneof` definitions in this type.
+  repeated string oneofs = 3;
+  // The protocol buffer options.
   repeated Option options = 4;
   // The source context.
   SourceContext source_context = 5;
@@ -57,9 +58,9 @@ message Type {
   Syntax syntax = 6;
 }
 
-// Field represents a single field of a message type.
+// A single field of a message type.
 message Field {
-  // Kind represents a basic field type.
+  // Basic field types.
   enum Kind {
     // Field type unknown.
     TYPE_UNKNOWN        = 0;
@@ -81,7 +82,7 @@ message Field {
     TYPE_BOOL           = 8;
     // Field type string.
     TYPE_STRING         = 9;
-    // Field type group (deprecated proto2 type)
+    // Field type group. Proto2 syntax only, and deprecated.
     TYPE_GROUP          = 10;
     // Field type message.
     TYPE_MESSAGE        = 11;
@@ -101,38 +102,40 @@ message Field {
     TYPE_SINT64         = 18;
   };
 
-  // Cardinality represents whether a field is optional, required, or
-  // repeated.
+  // Whether a field is optional, required, or repeated.
   enum Cardinality {
-    // The field cardinality is unknown. Typically an error condition.
+    // For fields with unknown cardinality.
     CARDINALITY_UNKNOWN = 0;
     // For optional fields.
     CARDINALITY_OPTIONAL = 1;
-    // For required fields. Not used for proto3.
+    // For required fields. Proto2 syntax only.
     CARDINALITY_REQUIRED = 2;
     // For repeated fields.
     CARDINALITY_REPEATED = 3;
   };
 
-  // The field kind.
+  // The field type.
   Kind kind = 1;
-  // The field cardinality, i.e. optional/required/repeated.
+  // The field cardinality.
   Cardinality cardinality = 2;
-  // The proto field number.
+  // The field number.
   int32 number = 3;
   // The field name.
   string name = 4;
-  // The type URL (without the scheme) when the type is MESSAGE or ENUM,
-  // such as `type.googleapis.com/google.protobuf.Empty`.
+  // The field type URL, without the scheme, for message or enumeration
+  // types. Example: `"type.googleapis.com/google.protobuf.Timestamp"`.
   string type_url = 6;
-  // Index in Type.oneofs. Starts at 1. Zero means no oneof mapping.
+  // The index of the field type in `Type.oneofs`, for message or enumeration
+  // types. The first type has index 1; zero means the type is not in the list.
   int32 oneof_index = 7;
   // Whether to use alternative packed wire representation.
   bool packed = 8;
-  // The proto options.
+  // The protocol buffer options.
   repeated Option options = 9;
-  // The JSON name for this field.
+  // The field JSON name.
   string json_name = 10;
+  // The string value of the default value of this field. Proto2 syntax only.
+  string default_value = 11;
 }
 
 // Enum type definition.
@@ -141,7 +144,7 @@ message Enum {
   string name = 1;
   // Enum value definitions.
   repeated EnumValue enumvalue = 2;
-  // Proto options for the enum type.
+  // Protocol buffer options.
   repeated Option options = 3;
   // The source context.
   SourceContext source_context = 4;
@@ -155,22 +158,23 @@ message EnumValue {
   string name = 1;
   // Enum value number.
   int32 number = 2;
-  // Proto options for the enum value.
+  // Protocol buffer options.
   repeated Option options = 3;
 }
 
-// Proto option attached to messages/fields/enums etc.
+// A protocol buffer option, which can be attached to a message, field,
+// enumeration, etc.
 message Option {
-  // Proto option name.
+  // The option's name. For example, `"java_package"`.
   string name = 1;
-  // Proto option value.
+  // The option's value. For example, `"com.google.protobuf"`.
   Any value = 2;
 }
 
-// Syntax specifies the syntax in which a service element was defined.
+// The syntax in which a protocol buffer element is defined.
 enum Syntax {
-  // Syntax "proto2"
+  // Syntax `proto2`.
   SYNTAX_PROTO2 = 0;
-  // Syntax "proto3"
+  // Syntax `proto3`.
   SYNTAX_PROTO3 = 1;
 }
diff --git a/src/google/protobuf/unittest_custom_options.proto b/src/google/protobuf/unittest_custom_options.proto
index d4d6e869..4cc0e362 100644
--- a/src/google/protobuf/unittest_custom_options.proto
+++ b/src/google/protobuf/unittest_custom_options.proto
@@ -392,3 +392,30 @@ message NestedOptionType {
     optional int32 nested_extension = 7912573 [(field_opt2) = 1005];
   }
 }
+
+// Custom message option that has a required enum field.
+// WARNING: this is strongly discouraged!
+message OldOptionType {
+  enum TestEnum {
+    OLD_VALUE = 0;
+  }
+  required TestEnum value = 1;
+}
+
+// Updated version of the custom option above.
+message NewOptionType {
+  enum TestEnum {
+    OLD_VALUE = 0;
+    NEW_VALUE = 1;
+  }
+  required TestEnum value = 1;
+}
+
+extend google.protobuf.MessageOptions {
+  optional OldOptionType required_enum_opt = 106161807;
+}
+
+// Test message using the "required_enum_opt" option defined above.
+message TestMessageWithRequiredEnumOption {
+  option (required_enum_opt) = { value: OLD_VALUE };
+}
diff --git a/src/google/protobuf/util/field_comparator.h b/src/google/protobuf/util/field_comparator.h
index ee676265..8b83c69f 100644
--- a/src/google/protobuf/util/field_comparator.h
+++ b/src/google/protobuf/util/field_comparator.h
@@ -93,7 +93,7 @@ class LIBPROTOBUF_EXPORT FieldComparator {
 
 // Basic implementation of FieldComparator.  Supports four modes of floating
 // point value comparison: exact, approximate using MathUtil::AlmostEqual
-// method, and arbitrarilly precise using MathUtil::WithinFracionOrMargin.
+// method, and arbitrarilly precise using MathUtil::WithinFractionOrMargin.
 class LIBPROTOBUF_EXPORT DefaultFieldComparator : public FieldComparator {
  public:
   enum FloatComparison {
diff --git a/src/google/protobuf/util/field_comparator_test.cc b/src/google/protobuf/util/field_comparator_test.cc
index d3d34602..23f7d51d 100644
--- a/src/google/protobuf/util/field_comparator_test.cc
+++ b/src/google/protobuf/util/field_comparator_test.cc
@@ -35,7 +35,12 @@
 #include <google/protobuf/unittest.pb.h>
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/stubs/mathutil.h>
-
+// This gtest header is put after mathutil.h intentionally. We have to do
+// this because mathutil.h includes mathlimits.h which requires cmath not
+// being included to compile on some versions of gcc:
+//   https://github.com/google/protobuf/blob/818c5eee08840355d70d2f3bdf1a2f17986a5e70/src/google/protobuf/stubs/mathlimits.h#L48
+// and the opensource version gtest.h header includes cmath transitively
+// somehow.
 #include <gtest/gtest.h>
 
 namespace google {
diff --git a/src/google/protobuf/util/internal/datapiece.cc b/src/google/protobuf/util/internal/datapiece.cc
index ea360798..b557429f 100644
--- a/src/google/protobuf/util/internal/datapiece.cc
+++ b/src/google/protobuf/util/internal/datapiece.cc
@@ -35,8 +35,8 @@
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/util/internal/utility.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/stubs/mathutil.h>
 #include <google/protobuf/stubs/mathlimits.h>
+#include <google/protobuf/stubs/mathutil.h>
 
 namespace google {
 namespace protobuf {
@@ -57,13 +57,8 @@ inline Status InvalidArgument(StringPiece value_str) {
   return Status(util::error::INVALID_ARGUMENT, value_str);
 }
 
-// For general conversion between
-//     int32, int64, uint32, uint64, double and float
-// except conversion between double and float.
 template <typename To, typename From>
-StatusOr<To> NumberConvertAndCheck(From before) {
-  if (::google::protobuf::internal::is_same<From, To>::value) return before;
-  To after = static_cast<To>(before);
+StatusOr<To> ValidateNumberConversion(To after, From before) {
   if (after == before &&
       MathUtil::Sign<From>(before) == MathUtil::Sign<To>(after)) {
     return after;
@@ -76,6 +71,27 @@ StatusOr<To> NumberConvertAndCheck(From before) {
   }
 }
 
+// For general conversion between
+//     int32, int64, uint32, uint64, double and float
+// except conversion between double and float.
+template <typename To, typename From>
+StatusOr<To> NumberConvertAndCheck(From before) {
+  if (::google::protobuf::internal::is_same<From, To>::value) return before;
+
+  To after = static_cast<To>(before);
+  return ValidateNumberConversion(after, before);
+}
+
+// For conversion to integer types (int32, int64, uint32, uint64) from floating
+// point types (double, float) only.
+template <typename To, typename From>
+StatusOr<To> FloatingPointToIntConvertAndCheck(From before) {
+  if (::google::protobuf::internal::is_same<From, To>::value) return before;
+
+  To after = static_cast<To>(before);
+  return ValidateNumberConversion(after, before);
+}
+
 // For conversion between double and float only.
 template <typename To, typename From>
 StatusOr<To> FloatingPointConvertAndCheck(From before) {
@@ -96,30 +112,50 @@ StatusOr<To> FloatingPointConvertAndCheck(From before) {
 }  // namespace
 
 StatusOr<int32> DataPiece::ToInt32() const {
-  if (type_ == TYPE_STRING) {
-    return StringToNumber<int32>(safe_strto32);
-  }
+  if (type_ == TYPE_STRING) return StringToNumber<int32>(safe_strto32);
+
+  if (type_ == TYPE_DOUBLE)
+    return FloatingPointToIntConvertAndCheck<int32, double>(double_);
+
+  if (type_ == TYPE_FLOAT)
+    return FloatingPointToIntConvertAndCheck<int32, float>(float_);
+
   return GenericConvert<int32>();
 }
 
 StatusOr<uint32> DataPiece::ToUint32() const {
-  if (type_ == TYPE_STRING) {
-    return StringToNumber<uint32>(safe_strtou32);
-  }
+  if (type_ == TYPE_STRING) return StringToNumber<uint32>(safe_strtou32);
+
+  if (type_ == TYPE_DOUBLE)
+    return FloatingPointToIntConvertAndCheck<uint32, double>(double_);
+
+  if (type_ == TYPE_FLOAT)
+    return FloatingPointToIntConvertAndCheck<uint32, float>(float_);
+
   return GenericConvert<uint32>();
 }
 
 StatusOr<int64> DataPiece::ToInt64() const {
-  if (type_ == TYPE_STRING) {
-    return StringToNumber<int64>(safe_strto64);
-  }
+  if (type_ == TYPE_STRING) return StringToNumber<int64>(safe_strto64);
+
+  if (type_ == TYPE_DOUBLE)
+    return FloatingPointToIntConvertAndCheck<int64, double>(double_);
+
+  if (type_ == TYPE_FLOAT)
+    return FloatingPointToIntConvertAndCheck<int64, float>(float_);
+
   return GenericConvert<int64>();
 }
 
 StatusOr<uint64> DataPiece::ToUint64() const {
-  if (type_ == TYPE_STRING) {
-    return StringToNumber<uint64>(safe_strtou64);
-  }
+  if (type_ == TYPE_STRING) return StringToNumber<uint64>(safe_strtou64);
+
+  if (type_ == TYPE_DOUBLE)
+    return FloatingPointToIntConvertAndCheck<uint64, double>(double_);
+
+  if (type_ == TYPE_FLOAT)
+    return FloatingPointToIntConvertAndCheck<uint64, float>(float_);
+
   return GenericConvert<uint64>();
 }
 
diff --git a/src/google/protobuf/util/internal/datapiece.h b/src/google/protobuf/util/internal/datapiece.h
index 2ab3fa88..f22bfe70 100644
--- a/src/google/protobuf/util/internal/datapiece.h
+++ b/src/google/protobuf/util/internal/datapiece.h
@@ -98,7 +98,8 @@ class LIBPROTOBUF_EXPORT DataPiece {
 
   static DataPiece NullData() { return DataPiece(TYPE_NULL, 0); }
 
-  virtual ~DataPiece() {}
+  virtual ~DataPiece() {
+  }
 
   // Accessors
   Type type() const { return type_; }
diff --git a/src/google/protobuf/util/internal/default_value_objectwriter.cc b/src/google/protobuf/util/internal/default_value_objectwriter.cc
index 97b248ff..a63e560d 100644
--- a/src/google/protobuf/util/internal/default_value_objectwriter.cc
+++ b/src/google/protobuf/util/internal/default_value_objectwriter.cc
@@ -33,6 +33,7 @@
 #include <google/protobuf/stubs/hash.h>
 
 #include <google/protobuf/util/internal/constants.h>
+#include <google/protobuf/util/internal/utility.h>
 #include <google/protobuf/stubs/map_util.h>
 
 namespace google {
@@ -42,13 +43,25 @@ using util::Status;
 using util::StatusOr;
 namespace converter {
 
+namespace {
+// Helper function to convert string value to given data type by calling the
+// passed converter function on the DataPiece created from "value" argument.
+// If value is empty or if conversion fails, the default_value is returned.
+template <typename T>
+T ConvertTo(StringPiece value, StatusOr<T> (DataPiece::*converter_fn)() const,
+            T default_value) {
+  if (value.empty()) return default_value;
+  StatusOr<T> result = (DataPiece(value).*converter_fn)();
+  return result.ok() ? result.ValueOrDie() : default_value;
+}
+}  // namespace
+
 DefaultValueObjectWriter::DefaultValueObjectWriter(
     TypeResolver* type_resolver, const google::protobuf::Type& type,
     ObjectWriter* ow)
     : typeinfo_(TypeInfo::NewTypeInfo(type_resolver)),
       own_typeinfo_(true),
       type_(type),
-      disable_normalize_(false),
       current_(NULL),
       root_(NULL),
       ow_(ow) {}
@@ -165,12 +178,6 @@ DefaultValueObjectWriter* DefaultValueObjectWriter::RenderNull(
   return this;
 }
 
-DefaultValueObjectWriter*
-DefaultValueObjectWriter::DisableCaseNormalizationForNextKey() {
-  disable_normalize_ = true;
-  return this;
-}
-
 DefaultValueObjectWriter::Node::Node(const string& name,
                                      const google::protobuf::Type* type,
                                      NodeKind kind, const DataPiece& data,
@@ -178,7 +185,6 @@ DefaultValueObjectWriter::Node::Node(const string& name,
     : name_(name),
       type_(type),
       kind_(kind),
-      disable_normalize_(false),
       is_any_(false),
       data_(data),
       is_placeholder_(is_placeholder) {}
@@ -198,10 +204,6 @@ DefaultValueObjectWriter::Node* DefaultValueObjectWriter::Node::FindChild(
 }
 
 void DefaultValueObjectWriter::Node::WriteTo(ObjectWriter* ow) {
-  if (disable_normalize_) {
-    ow->DisableCaseNormalizationForNextKey();
-  }
-
   if (kind_ == PRIMITIVE) {
     ObjectWriter::RenderDataPieceTo(data_, name_, ow);
     return;
@@ -324,6 +326,7 @@ void DefaultValueObjectWriter::Node::PopulateChildren(
         }
       }
     }
+
     if (!is_map &&
         field.cardinality() ==
             google::protobuf::Field_Cardinality_CARDINALITY_REPEATED) {
@@ -336,11 +339,11 @@ void DefaultValueObjectWriter::Node::PopulateChildren(
 
     // If the child field is of primitive type, sets its data to the default
     // value of its type.
-    google::protobuf::scoped_ptr<Node> child(
-        new Node(field.json_name(), field_type, kind,
-                 kind == PRIMITIVE ? CreateDefaultDataPieceForField(field)
-                                   : DataPiece::NullData(),
-                 true));
+    google::protobuf::scoped_ptr<Node> child(new Node(
+        field.json_name(), field_type, kind,
+        kind == PRIMITIVE ? CreateDefaultDataPieceForField(field, typeinfo)
+                          : DataPiece::NullData(),
+        true));
     new_children.push_back(child.release());
   }
   // Adds all leftover nodes in children_ to the beginning of new_child.
@@ -363,41 +366,68 @@ void DefaultValueObjectWriter::MaybePopulateChildrenOfAny(Node* node) {
   }
 }
 
+DataPiece DefaultValueObjectWriter::FindEnumDefault(
+    const google::protobuf::Field& field, const TypeInfo* typeinfo) {
+  if (!field.default_value().empty()) return DataPiece(field.default_value());
+
+  const google::protobuf::Enum* enum_type =
+      typeinfo->GetEnumByTypeUrl(field.type_url());
+  if (!enum_type) {
+    GOOGLE_LOG(WARNING) << "Could not find enum with type '" << field.type_url()
+                 << "'";
+    return DataPiece::NullData();
+  }
+  // We treat the first value as the default if none is specified.
+  return enum_type->enumvalue_size() > 0
+             ? DataPiece(enum_type->enumvalue(0).name())
+             : DataPiece::NullData();
+}
+
 DataPiece DefaultValueObjectWriter::CreateDefaultDataPieceForField(
-    const google::protobuf::Field& field) {
+    const google::protobuf::Field& field, const TypeInfo* typeinfo) {
   switch (field.kind()) {
     case google::protobuf::Field_Kind_TYPE_DOUBLE: {
-      return DataPiece(static_cast<double>(0));
+      return DataPiece(ConvertTo<double>(
+          field.default_value(), &DataPiece::ToDouble, static_cast<double>(0)));
     }
     case google::protobuf::Field_Kind_TYPE_FLOAT: {
-      return DataPiece(static_cast<float>(0));
+      return DataPiece(ConvertTo<float>(
+          field.default_value(), &DataPiece::ToFloat, static_cast<float>(0)));
     }
     case google::protobuf::Field_Kind_TYPE_INT64:
     case google::protobuf::Field_Kind_TYPE_SINT64:
     case google::protobuf::Field_Kind_TYPE_SFIXED64: {
-      return DataPiece(static_cast<int64>(0));
+      return DataPiece(ConvertTo<int64>(
+          field.default_value(), &DataPiece::ToInt64, static_cast<int64>(0)));
     }
     case google::protobuf::Field_Kind_TYPE_UINT64:
     case google::protobuf::Field_Kind_TYPE_FIXED64: {
-      return DataPiece(static_cast<uint64>(0));
+      return DataPiece(ConvertTo<uint64>(
+          field.default_value(), &DataPiece::ToUint64, static_cast<uint64>(0)));
     }
     case google::protobuf::Field_Kind_TYPE_INT32:
     case google::protobuf::Field_Kind_TYPE_SINT32:
     case google::protobuf::Field_Kind_TYPE_SFIXED32: {
-      return DataPiece(static_cast<int32>(0));
+      return DataPiece(ConvertTo<int32>(
+          field.default_value(), &DataPiece::ToInt32, static_cast<int32>(0)));
     }
     case google::protobuf::Field_Kind_TYPE_BOOL: {
-      return DataPiece(false);
+      return DataPiece(
+          ConvertTo<bool>(field.default_value(), &DataPiece::ToBool, false));
     }
     case google::protobuf::Field_Kind_TYPE_STRING: {
-      return DataPiece(string());
+      return DataPiece(field.default_value());
     }
     case google::protobuf::Field_Kind_TYPE_BYTES: {
-      return DataPiece("", false);
+      return DataPiece(field.default_value(), false);
     }
     case google::protobuf::Field_Kind_TYPE_UINT32:
     case google::protobuf::Field_Kind_TYPE_FIXED32: {
-      return DataPiece(static_cast<uint32>(0));
+      return DataPiece(ConvertTo<uint32>(
+          field.default_value(), &DataPiece::ToUint32, static_cast<uint32>(0)));
+    }
+    case google::protobuf::Field_Kind_TYPE_ENUM: {
+      return FindEnumDefault(field, typeinfo);
     }
     default: { return DataPiece::NullData(); }
   }
@@ -408,7 +438,6 @@ DefaultValueObjectWriter* DefaultValueObjectWriter::StartObject(
   if (current_ == NULL) {
     root_.reset(new Node(name.ToString(), &type_, OBJECT, DataPiece::NullData(),
                          false));
-    root_->set_disable_normalize(GetAndResetDisableNormalize());
     root_->PopulateChildren(typeinfo_);
     current_ = root_.get();
     return this;
@@ -428,7 +457,6 @@ DefaultValueObjectWriter* DefaultValueObjectWriter::StartObject(
   }
 
   child->set_is_placeholder(false);
-  child->set_disable_normalize(GetAndResetDisableNormalize());
   if (child->kind() == OBJECT && child->number_of_children() == 0) {
     child->PopulateChildren(typeinfo_);
   }
@@ -454,21 +482,18 @@ DefaultValueObjectWriter* DefaultValueObjectWriter::StartList(
   if (current_ == NULL) {
     root_.reset(
         new Node(name.ToString(), &type_, LIST, DataPiece::NullData(), false));
-    root_->set_disable_normalize(GetAndResetDisableNormalize());
     current_ = root_.get();
     return this;
   }
   MaybePopulateChildrenOfAny(current_);
   Node* child = current_->FindChild(name);
   if (child == NULL || child->kind() != LIST) {
-    GOOGLE_LOG(WARNING) << "Cannot find field '" << name << "'.";
     google::protobuf::scoped_ptr<Node> node(
         new Node(name.ToString(), NULL, LIST, DataPiece::NullData(), false));
     child = node.get();
     current_->AddChild(node.release());
   }
   child->set_is_placeholder(false);
-  child->set_disable_normalize(GetAndResetDisableNormalize());
 
   stack_.push(current_);
   current_ = child;
@@ -526,7 +551,6 @@ void DefaultValueObjectWriter::RenderDataPiece(StringPiece name,
   } else {
     child->set_data(data);
   }
-  child->set_disable_normalize(GetAndResetDisableNormalize());
 }
 
 }  // namespace converter
diff --git a/src/google/protobuf/util/internal/default_value_objectwriter.h b/src/google/protobuf/util/internal/default_value_objectwriter.h
index bcb526e8..695b9dd8 100644
--- a/src/google/protobuf/util/internal/default_value_objectwriter.h
+++ b/src/google/protobuf/util/internal/default_value_objectwriter.h
@@ -98,8 +98,6 @@ class LIBPROTOBUF_EXPORT DefaultValueObjectWriter : public ObjectWriter {
 
   virtual DefaultValueObjectWriter* RenderNull(StringPiece name);
 
-  virtual DefaultValueObjectWriter* DisableCaseNormalizationForNextKey();
-
  private:
   enum NodeKind {
     PRIMITIVE = 0,
@@ -149,10 +147,6 @@ class LIBPROTOBUF_EXPORT DefaultValueObjectWriter : public ObjectWriter {
 
     void set_data(const DataPiece& data) { data_ = data; }
 
-    void set_disable_normalize(bool disable_normalize) {
-      disable_normalize_ = disable_normalize;
-    }
-
     bool is_any() { return is_any_; }
 
     void set_is_any(bool is_any) { is_any_ = is_any; }
@@ -176,8 +170,6 @@ class LIBPROTOBUF_EXPORT DefaultValueObjectWriter : public ObjectWriter {
     const google::protobuf::Type* type_;
     // The kind of this node.
     NodeKind kind_;
-    // Whether to disable case normalization of the name.
-    bool disable_normalize_;
     // Whether this is a node for "Any".
     bool is_any_;
     // The data of this node when it is a leaf node.
@@ -201,16 +193,17 @@ class LIBPROTOBUF_EXPORT DefaultValueObjectWriter : public ObjectWriter {
 
   // Creates a DataPiece containing the default value of the type of the field.
   static DataPiece CreateDefaultDataPieceForField(
-      const google::protobuf::Field& field);
-
-  // Returns disable_normalize_ and reset it to false.
-  bool GetAndResetDisableNormalize() {
-    return disable_normalize_ ? (disable_normalize_ = false, true) : false;
-  }
+      const google::protobuf::Field& field, const TypeInfo* typeinfo);
 
   // Adds or replaces the data_ of a primitive child node.
   void RenderDataPiece(StringPiece name, const DataPiece& data);
 
+  // Returns the default enum value as a DataPiece, or the first enum value if
+  // there is no default. For proto3, where we cannot specify an explicit
+  // default, a zero value will always be returned.
+  static DataPiece FindEnumDefault(const google::protobuf::Field& field,
+                                   const TypeInfo* typeinfo);
+
   // Type information for all the types used in the descriptor. Used to find
   // google::protobuf::Type of nested messages/enums.
   const TypeInfo* typeinfo_;
@@ -221,8 +214,6 @@ class LIBPROTOBUF_EXPORT DefaultValueObjectWriter : public ObjectWriter {
   // Holds copies of strings passed to RenderString.
   vector<string*> string_values_;
 
-  // Whether to disable case normalization of the next node.
-  bool disable_normalize_;
   // The current Node. Owned by its parents.
   Node* current_;
   // The root Node.
diff --git a/src/google/protobuf/util/internal/default_value_objectwriter_test.cc b/src/google/protobuf/util/internal/default_value_objectwriter_test.cc
index 237d0722..b7a537ab 100644
--- a/src/google/protobuf/util/internal/default_value_objectwriter_test.cc
+++ b/src/google/protobuf/util/internal/default_value_objectwriter_test.cc
@@ -43,21 +43,19 @@ namespace testing {
 
 using google::protobuf::testing::DefaultValueTest;
 
-// Tests to cover some basic DefaultValueObjectWriter use cases. More tests are
-// in the marshalling_test.cc and translator_integration_test.cc.
-class DefaultValueObjectWriterTest
+// Base class for setting up required state for running default values tests on
+// different descriptors.
+class BaseDefaultValueObjectWriterTest
     : public ::testing::TestWithParam<testing::TypeInfoSource> {
  protected:
-  DefaultValueObjectWriterTest()
+  explicit BaseDefaultValueObjectWriterTest(const Descriptor* descriptor)
       : helper_(GetParam()), mock_(), expects_(&mock_) {
-    helper_.ResetTypeInfo(DefaultValueTest::descriptor());
+    helper_.ResetTypeInfo(descriptor);
     testing_.reset(helper_.NewDefaultValueWriter(
-        string(kTypeServiceBaseUrl) + "/" +
-            DefaultValueTest::descriptor()->full_name(),
-        &mock_));
+        string(kTypeServiceBaseUrl) + "/" + descriptor->full_name(), &mock_));
   }
 
-  virtual ~DefaultValueObjectWriterTest() {}
+  ~BaseDefaultValueObjectWriterTest() override {}
 
   TypeInfoTestHelper helper_;
   MockObjectWriter mock_;
@@ -65,6 +63,15 @@ class DefaultValueObjectWriterTest
   google::protobuf::scoped_ptr<DefaultValueObjectWriter> testing_;
 };
 
+// Tests to cover some basic DefaultValueObjectWriter use cases. More tests are
+// in the marshalling_test.cc and translator_integration_test.cc.
+class DefaultValueObjectWriterTest : public BaseDefaultValueObjectWriterTest {
+ protected:
+  DefaultValueObjectWriterTest()
+      : BaseDefaultValueObjectWriterTest(DefaultValueTest::descriptor()) {}
+  ~DefaultValueObjectWriterTest() override {}
+};
+
 INSTANTIATE_TEST_CASE_P(DifferentTypeInfoSourceTest,
                         DefaultValueObjectWriterTest,
                         ::testing::Values(
@@ -74,6 +81,8 @@ TEST_P(DefaultValueObjectWriterTest, Empty) {
   // Set expectation
   expects_.StartObject("")
       ->RenderDouble("doubleValue", 0.0)
+      ->StartList("repeatedDouble")
+      ->EndList()
       ->RenderFloat("floatValue", 0.0)
       ->RenderInt64("int64Value", 0)
       ->RenderUint64("uint64Value", 0)
@@ -82,6 +91,7 @@ TEST_P(DefaultValueObjectWriterTest, Empty) {
       ->RenderBool("boolValue", false)
       ->RenderString("stringValue", "")
       ->RenderBytes("bytesValue", "")
+      ->RenderString("enumValue", "ENUM_FIRST")
       ->EndObject();
 
   // Actual testing
@@ -92,6 +102,8 @@ TEST_P(DefaultValueObjectWriterTest, NonDefaultDouble) {
   // Set expectation
   expects_.StartObject("")
       ->RenderDouble("doubleValue", 1.0)
+      ->StartList("repeatedDouble")
+      ->EndList()
       ->RenderFloat("floatValue", 0.0)
       ->RenderInt64("int64Value", 0)
       ->RenderUint64("uint64Value", 0)
@@ -99,6 +111,7 @@ TEST_P(DefaultValueObjectWriterTest, NonDefaultDouble) {
       ->RenderUint32("uint32Value", 0)
       ->RenderBool("boolValue", false)
       ->RenderString("stringValue", "")
+      ->RenderString("enumValue", "ENUM_FIRST")
       ->EndObject();
 
   // Actual testing
@@ -109,6 +122,8 @@ TEST_P(DefaultValueObjectWriterTest, ShouldRetainUnknownField) {
   // Set expectation
   expects_.StartObject("")
       ->RenderDouble("doubleValue", 1.0)
+      ->StartList("repeatedDouble")
+      ->EndList()
       ->RenderFloat("floatValue", 0.0)
       ->RenderInt64("int64Value", 0)
       ->RenderUint64("uint64Value", 0)
@@ -120,6 +135,7 @@ TEST_P(DefaultValueObjectWriterTest, ShouldRetainUnknownField) {
       ->StartObject("unknownObject")
       ->RenderString("unknown", "def")
       ->EndObject()
+      ->RenderString("enumValue", "ENUM_FIRST")
       ->EndObject();
 
   // Actual testing
@@ -132,6 +148,7 @@ TEST_P(DefaultValueObjectWriterTest, ShouldRetainUnknownField) {
       ->EndObject();
 }
 
+
 }  // namespace testing
 }  // namespace converter
 }  // namespace util
diff --git a/src/google/protobuf/util/internal/error_listener.h b/src/google/protobuf/util/internal/error_listener.h
index 2699684d..3f063936 100644
--- a/src/google/protobuf/util/internal/error_listener.h
+++ b/src/google/protobuf/util/internal/error_listener.h
@@ -31,11 +31,13 @@
 #ifndef GOOGLE_PROTOBUF_UTIL_CONVERTER_ERROR_LISTENER_H__
 #define GOOGLE_PROTOBUF_UTIL_CONVERTER_ERROR_LISTENER_H__
 
+#include <algorithm>
 #include <memory>
 #ifndef _SHARED_PTR_H
 #include <google/protobuf/stubs/shared_ptr.h>
 #endif
 #include <string>
+#include <vector>
 
 #include <google/protobuf/stubs/callback.h>
 #include <google/protobuf/stubs/common.h>
diff --git a/src/google/protobuf/util/internal/json_objectwriter_test.cc b/src/google/protobuf/util/internal/json_objectwriter_test.cc
index dcd60601..9d820162 100644
--- a/src/google/protobuf/util/internal/json_objectwriter_test.cc
+++ b/src/google/protobuf/util/internal/json_objectwriter_test.cc
@@ -47,8 +47,7 @@ class JsonObjectWriterTest : public ::testing::Test {
   JsonObjectWriterTest()
       : str_stream_(new StringOutputStream(&output_)),
         out_stream_(new CodedOutputStream(str_stream_)),
-        ow_(NULL) {
-  }
+        ow_(NULL) {}
 
   virtual ~JsonObjectWriterTest() {
     delete ow_;
@@ -64,36 +63,34 @@ class JsonObjectWriterTest : public ::testing::Test {
 
 TEST_F(JsonObjectWriterTest, EmptyRootObject) {
   ow_ = new JsonObjectWriter("", out_stream_);
-  ow_->StartObject("")
-     ->EndObject();
+  ow_->StartObject("")->EndObject();
   EXPECT_EQ("{}", output_.substr(0, out_stream_->ByteCount()));
 }
 
 TEST_F(JsonObjectWriterTest, EmptyObject) {
   ow_ = new JsonObjectWriter("", out_stream_);
   ow_->StartObject("")
-       ->RenderString("test", "value")
-       ->StartObject("empty")
-       ->EndObject()
-     ->EndObject();
+      ->RenderString("test", "value")
+      ->StartObject("empty")
+      ->EndObject()
+      ->EndObject();
   EXPECT_EQ("{\"test\":\"value\",\"empty\":{}}",
             output_.substr(0, out_stream_->ByteCount()));
 }
 
 TEST_F(JsonObjectWriterTest, EmptyRootList) {
   ow_ = new JsonObjectWriter("", out_stream_);
-  ow_->StartList("")
-     ->EndList();
+  ow_->StartList("")->EndList();
   EXPECT_EQ("[]", output_.substr(0, out_stream_->ByteCount()));
 }
 
 TEST_F(JsonObjectWriterTest, EmptyList) {
   ow_ = new JsonObjectWriter("", out_stream_);
   ow_->StartObject("")
-       ->RenderString("test", "value")
-       ->StartList("empty")
-       ->EndList()
-     ->EndObject();
+      ->RenderString("test", "value")
+      ->StartList("empty")
+      ->EndList()
+      ->EndObject();
   EXPECT_EQ("{\"test\":\"value\",\"empty\":[]}",
             output_.substr(0, out_stream_->ByteCount()));
 }
@@ -101,10 +98,10 @@ TEST_F(JsonObjectWriterTest, EmptyList) {
 TEST_F(JsonObjectWriterTest, ObjectInObject) {
   ow_ = new JsonObjectWriter("", out_stream_);
   ow_->StartObject("")
-       ->StartObject("nested")
-         ->RenderString("field", "value")
-       ->EndObject()
-     ->EndObject();
+      ->StartObject("nested")
+      ->RenderString("field", "value")
+      ->EndObject()
+      ->EndObject();
   EXPECT_EQ("{\"nested\":{\"field\":\"value\"}}",
             output_.substr(0, out_stream_->ByteCount()));
 }
@@ -112,10 +109,10 @@ TEST_F(JsonObjectWriterTest, ObjectInObject) {
 TEST_F(JsonObjectWriterTest, ListInObject) {
   ow_ = new JsonObjectWriter("", out_stream_);
   ow_->StartObject("")
-       ->StartList("nested")
-         ->RenderString("", "value")
-       ->EndList()
-     ->EndObject();
+      ->StartList("nested")
+      ->RenderString("", "value")
+      ->EndList()
+      ->EndObject();
   EXPECT_EQ("{\"nested\":[\"value\"]}",
             output_.substr(0, out_stream_->ByteCount()));
 }
@@ -123,10 +120,10 @@ TEST_F(JsonObjectWriterTest, ListInObject) {
 TEST_F(JsonObjectWriterTest, ObjectInList) {
   ow_ = new JsonObjectWriter("", out_stream_);
   ow_->StartList("")
-       ->StartObject("")
-         ->RenderString("field", "value")
-       ->EndObject()
-     ->EndList();
+      ->StartObject("")
+      ->RenderString("field", "value")
+      ->EndObject()
+      ->EndList();
   EXPECT_EQ("[{\"field\":\"value\"}]",
             output_.substr(0, out_stream_->ByteCount()));
 }
@@ -134,10 +131,10 @@ TEST_F(JsonObjectWriterTest, ObjectInList) {
 TEST_F(JsonObjectWriterTest, ListInList) {
   ow_ = new JsonObjectWriter("", out_stream_);
   ow_->StartList("")
-       ->StartList("")
-         ->RenderString("", "value")
-       ->EndList()
-     ->EndList();
+      ->StartList("")
+      ->RenderString("", "value")
+      ->EndList()
+      ->EndList();
   EXPECT_EQ("[[\"value\"]]", output_.substr(0, out_stream_->ByteCount()));
 }
 
@@ -156,14 +153,18 @@ TEST_F(JsonObjectWriterTest, RenderPrimitives) {
       ->EndObject();
   EXPECT_EQ(
       "{\"bool\":true,"
-      "\"double\":" + ValueAsString<double>(1.7976931348623157e+308) + ","
-      "\"float\":" + ValueAsString<float>(3.4028235e+38) + ","
-      "\"int\":-2147483648,"
-      "\"long\":\"-9223372036854775808\","
-      "\"bytes\":\"YWJyYWNhZGFicmE=\","
-      "\"string\":\"string\","
-      "\"emptybytes\":\"\","
-      "\"emptystring\":\"\"}",
+      "\"double\":" +
+          ValueAsString<double>(std::numeric_limits<double>::max()) +
+          ","
+          "\"float\":" +
+          ValueAsString<float>(std::numeric_limits<float>::max()) +
+          ","
+          "\"int\":-2147483648,"
+          "\"long\":\"-9223372036854775808\","
+          "\"bytes\":\"YWJyYWNhZGFicmE=\","
+          "\"string\":\"string\","
+          "\"emptybytes\":\"\","
+          "\"emptystring\":\"\"}",
       output_.substr(0, out_stream_->ByteCount()));
 }
 
@@ -181,81 +182,83 @@ TEST_F(JsonObjectWriterTest, BytesEncodesAsNonWebSafeBase64) {
 TEST_F(JsonObjectWriterTest, PrettyPrintList) {
   ow_ = new JsonObjectWriter(" ", out_stream_);
   ow_->StartObject("")
-       ->StartList("items")
-         ->RenderString("", "item1")
-         ->RenderString("", "item2")
-         ->RenderString("", "item3")
-       ->EndList()
-       ->StartList("empty")
-       ->EndList()
-     ->EndObject();
-  EXPECT_EQ("{\n"
-            " \"items\": [\n"
-            "  \"item1\",\n"
-            "  \"item2\",\n"
-            "  \"item3\"\n"
-            " ],\n"
-            " \"empty\": []\n"
-            "}\n",
-            output_.substr(0, out_stream_->ByteCount()));
+      ->StartList("items")
+      ->RenderString("", "item1")
+      ->RenderString("", "item2")
+      ->RenderString("", "item3")
+      ->EndList()
+      ->StartList("empty")
+      ->EndList()
+      ->EndObject();
+  EXPECT_EQ(
+      "{\n"
+      " \"items\": [\n"
+      "  \"item1\",\n"
+      "  \"item2\",\n"
+      "  \"item3\"\n"
+      " ],\n"
+      " \"empty\": []\n"
+      "}\n",
+      output_.substr(0, out_stream_->ByteCount()));
 }
 
 TEST_F(JsonObjectWriterTest, PrettyPrintObject) {
   ow_ = new JsonObjectWriter(" ", out_stream_);
   ow_->StartObject("")
-       ->StartObject("items")
-         ->RenderString("key1", "item1")
-         ->RenderString("key2", "item2")
-         ->RenderString("key3", "item3")
-       ->EndObject()
-       ->StartObject("empty")
-       ->EndObject()
-     ->EndObject();
-  EXPECT_EQ("{\n"
-            " \"items\": {\n"
-            "  \"key1\": \"item1\",\n"
-            "  \"key2\": \"item2\",\n"
-            "  \"key3\": \"item3\"\n"
-            " },\n"
-            " \"empty\": {}\n"
-            "}\n",
-            output_.substr(0, out_stream_->ByteCount()));
+      ->StartObject("items")
+      ->RenderString("key1", "item1")
+      ->RenderString("key2", "item2")
+      ->RenderString("key3", "item3")
+      ->EndObject()
+      ->StartObject("empty")
+      ->EndObject()
+      ->EndObject();
+  EXPECT_EQ(
+      "{\n"
+      " \"items\": {\n"
+      "  \"key1\": \"item1\",\n"
+      "  \"key2\": \"item2\",\n"
+      "  \"key3\": \"item3\"\n"
+      " },\n"
+      " \"empty\": {}\n"
+      "}\n",
+      output_.substr(0, out_stream_->ByteCount()));
 }
 
 TEST_F(JsonObjectWriterTest, PrettyPrintEmptyObjectInEmptyList) {
   ow_ = new JsonObjectWriter(" ", out_stream_);
   ow_->StartObject("")
-       ->StartList("list")
-         ->StartObject("")
-         ->EndObject()
-       ->EndList()
-     ->EndObject();
-  EXPECT_EQ("{\n"
-            " \"list\": [\n"
-            "  {}\n"
-            " ]\n"
-            "}\n",
-            output_.substr(0, out_stream_->ByteCount()));
+      ->StartList("list")
+      ->StartObject("")
+      ->EndObject()
+      ->EndList()
+      ->EndObject();
+  EXPECT_EQ(
+      "{\n"
+      " \"list\": [\n"
+      "  {}\n"
+      " ]\n"
+      "}\n",
+      output_.substr(0, out_stream_->ByteCount()));
 }
 
 TEST_F(JsonObjectWriterTest, PrettyPrintDoubleIndent) {
   ow_ = new JsonObjectWriter("  ", out_stream_);
   ow_->StartObject("")
-       ->RenderBool("bool", true)
-       ->RenderInt32("int", 42)
-     ->EndObject();
-  EXPECT_EQ("{\n"
-            "  \"bool\": true,\n"
-            "  \"int\": 42\n"
-            "}\n",
-            output_.substr(0, out_stream_->ByteCount()));
+      ->RenderBool("bool", true)
+      ->RenderInt32("int", 42)
+      ->EndObject();
+  EXPECT_EQ(
+      "{\n"
+      "  \"bool\": true,\n"
+      "  \"int\": 42\n"
+      "}\n",
+      output_.substr(0, out_stream_->ByteCount()));
 }
 
 TEST_F(JsonObjectWriterTest, StringsEscapedAndEnclosedInDoubleQuotes) {
   ow_ = new JsonObjectWriter("", out_stream_);
-  ow_->StartObject("")
-       ->RenderString("string", "'<>&amp;\\\"\r\n")
-     ->EndObject();
+  ow_->StartObject("")->RenderString("string", "'<>&amp;\\\"\r\n")->EndObject();
   EXPECT_EQ("{\"string\":\"'\\u003c\\u003e&amp;\\\\\\\"\\r\\n\"}",
             output_.substr(0, out_stream_->ByteCount()));
 }
@@ -263,13 +266,13 @@ TEST_F(JsonObjectWriterTest, StringsEscapedAndEnclosedInDoubleQuotes) {
 TEST_F(JsonObjectWriterTest, Stringification) {
   ow_ = new JsonObjectWriter("", out_stream_);
   ow_->StartObject("")
-       ->RenderDouble("double_nan", std::numeric_limits<double>::quiet_NaN())
-       ->RenderFloat("float_nan", std::numeric_limits<float>::quiet_NaN())
-       ->RenderDouble("double_pos", std::numeric_limits<double>::infinity())
-       ->RenderFloat("float_pos", std::numeric_limits<float>::infinity())
-       ->RenderDouble("double_neg", -std::numeric_limits<double>::infinity())
-       ->RenderFloat("float_neg", -std::numeric_limits<float>::infinity())
-     ->EndObject();
+      ->RenderDouble("double_nan", std::numeric_limits<double>::quiet_NaN())
+      ->RenderFloat("float_nan", std::numeric_limits<float>::quiet_NaN())
+      ->RenderDouble("double_pos", std::numeric_limits<double>::infinity())
+      ->RenderFloat("float_pos", std::numeric_limits<float>::infinity())
+      ->RenderDouble("double_neg", -std::numeric_limits<double>::infinity())
+      ->RenderFloat("float_neg", -std::numeric_limits<float>::infinity())
+      ->EndObject();
   EXPECT_EQ(
       "{\"double_nan\":\"NaN\","
       "\"float_nan\":\"NaN\","
diff --git a/src/google/protobuf/util/internal/json_stream_parser.cc b/src/google/protobuf/util/internal/json_stream_parser.cc
index a7ef7fe2..df916751 100644
--- a/src/google/protobuf/util/internal/json_stream_parser.cc
+++ b/src/google/protobuf/util/internal/json_stream_parser.cc
@@ -157,10 +157,10 @@ util::Status JsonStreamParser::FinishParse() {
     char* coerced = internal::UTF8CoerceToStructurallyValid(leftover_, utf8.get(), ' ');
     p_ = json_ = StringPiece(coerced, leftover_.size());
   } else {
+    p_ = json_ = leftover_;
     if (!internal::IsStructurallyValidUTF8(leftover_)) {
       return ReportFailure("Encountered non UTF-8 code points.");
     }
-    p_ = json_ = leftover_;
   }
 
   // Parse the remainder in finishing mode, which reports errors for things like
diff --git a/src/google/protobuf/util/internal/json_stream_parser_test.cc b/src/google/protobuf/util/internal/json_stream_parser_test.cc
index c833ed1f..3414826e 100644
--- a/src/google/protobuf/util/internal/json_stream_parser_test.cc
+++ b/src/google/protobuf/util/internal/json_stream_parser_test.cc
@@ -348,6 +348,7 @@ TEST_F(JsonStreamParserTest, RejectNonUtf8WhenNotCoerced) {
   for (int i = 0; i <= json.length(); ++i) {
     DoErrorTest(json, i, "Encountered non UTF-8 code points.");
   }
+  DoErrorTest("\xFF{}", 0, "Encountered non UTF-8 code points.");
 }
 
 #ifndef _MSC_VER
diff --git a/src/google/protobuf/util/internal/object_writer.h b/src/google/protobuf/util/internal/object_writer.h
index 20bd3627..e695f45e 100644
--- a/src/google/protobuf/util/internal/object_writer.h
+++ b/src/google/protobuf/util/internal/object_writer.h
@@ -101,11 +101,6 @@ class LIBPROTOBUF_EXPORT ObjectWriter {
   // Renders a Null value.
   virtual ObjectWriter* RenderNull(StringPiece name) = 0;
 
-  // Disables case normalization. Any RenderTYPE call after calling this
-  // function will output the name field as-is. No normalization is attempted on
-  // it. This setting is reset immediately after the next RenderTYPE is called.
-  virtual ObjectWriter* DisableCaseNormalizationForNextKey() { return this; }
-
   // Renders a DataPiece object to a ObjectWriter.
   static void RenderDataPieceTo(const DataPiece& data, StringPiece name,
                                 ObjectWriter* ow);
diff --git a/src/google/protobuf/util/internal/proto_writer.cc b/src/google/protobuf/util/internal/proto_writer.cc
new file mode 100644
index 00000000..47e0009e
--- /dev/null
+++ b/src/google/protobuf/util/internal/proto_writer.cc
@@ -0,0 +1,744 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <google/protobuf/util/internal/proto_writer.h>
+
+#include <functional>
+#include <stack>
+
+#include <google/protobuf/stubs/once.h>
+#include <google/protobuf/stubs/time.h>
+#include <google/protobuf/wire_format_lite.h>
+#include <google/protobuf/util/internal/field_mask_utility.h>
+#include <google/protobuf/util/internal/object_location_tracker.h>
+#include <google/protobuf/util/internal/constants.h>
+#include <google/protobuf/util/internal/utility.h>
+#include <google/protobuf/stubs/strutil.h>
+#include <google/protobuf/stubs/map_util.h>
+#include <google/protobuf/stubs/statusor.h>
+
+
+namespace google {
+namespace protobuf {
+namespace util {
+namespace converter {
+
+using google::protobuf::internal::WireFormatLite;
+using google::protobuf::io::CodedOutputStream;
+using util::error::INVALID_ARGUMENT;
+using util::Status;
+using util::StatusOr;
+
+
+ProtoWriter::ProtoWriter(TypeResolver* type_resolver,
+                         const google::protobuf::Type& type,
+                         strings::ByteSink* output, ErrorListener* listener)
+    : master_type_(type),
+      typeinfo_(TypeInfo::NewTypeInfo(type_resolver)),
+      own_typeinfo_(true),
+      done_(false),
+      element_(NULL),
+      size_insert_(),
+      output_(output),
+      buffer_(),
+      adapter_(&buffer_),
+      stream_(new CodedOutputStream(&adapter_)),
+      listener_(listener),
+      invalid_depth_(0),
+      tracker_(new ObjectLocationTracker()) {}
+
+ProtoWriter::ProtoWriter(const TypeInfo* typeinfo,
+                         const google::protobuf::Type& type,
+                         strings::ByteSink* output, ErrorListener* listener)
+    : master_type_(type),
+      typeinfo_(typeinfo),
+      own_typeinfo_(false),
+      done_(false),
+      element_(NULL),
+      size_insert_(),
+      output_(output),
+      buffer_(),
+      adapter_(&buffer_),
+      stream_(new CodedOutputStream(&adapter_)),
+      listener_(listener),
+      invalid_depth_(0),
+      tracker_(new ObjectLocationTracker()) {}
+
+ProtoWriter::~ProtoWriter() {
+  if (own_typeinfo_) {
+    delete typeinfo_;
+  }
+  if (element_ == NULL) return;
+  // Cleanup explicitly in order to avoid destructor stack overflow when input
+  // is deeply nested.
+  // Cast to BaseElement to avoid doing additional checks (like missing fields)
+  // during pop().
+  google::protobuf::scoped_ptr<BaseElement> element(
+      static_cast<BaseElement*>(element_.get())->pop<BaseElement>());
+  while (element != NULL) {
+    element.reset(element->pop<BaseElement>());
+  }
+}
+
+namespace {
+
+// Writes an INT32 field, including tag to the stream.
+inline Status WriteInt32(int field_number, const DataPiece& data,
+                         CodedOutputStream* stream) {
+  StatusOr<int32> i32 = data.ToInt32();
+  if (i32.ok()) {
+    WireFormatLite::WriteInt32(field_number, i32.ValueOrDie(), stream);
+  }
+  return i32.status();
+}
+
+// writes an SFIXED32 field, including tag, to the stream.
+inline Status WriteSFixed32(int field_number, const DataPiece& data,
+                            CodedOutputStream* stream) {
+  StatusOr<int32> i32 = data.ToInt32();
+  if (i32.ok()) {
+    WireFormatLite::WriteSFixed32(field_number, i32.ValueOrDie(), stream);
+  }
+  return i32.status();
+}
+
+// Writes an SINT32 field, including tag, to the stream.
+inline Status WriteSInt32(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<int32> i32 = data.ToInt32();
+  if (i32.ok()) {
+    WireFormatLite::WriteSInt32(field_number, i32.ValueOrDie(), stream);
+  }
+  return i32.status();
+}
+
+// Writes a FIXED32 field, including tag, to the stream.
+inline Status WriteFixed32(int field_number, const DataPiece& data,
+                           CodedOutputStream* stream) {
+  StatusOr<uint32> u32 = data.ToUint32();
+  if (u32.ok()) {
+    WireFormatLite::WriteFixed32(field_number, u32.ValueOrDie(), stream);
+  }
+  return u32.status();
+}
+
+// Writes a UINT32 field, including tag, to the stream.
+inline Status WriteUInt32(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<uint32> u32 = data.ToUint32();
+  if (u32.ok()) {
+    WireFormatLite::WriteUInt32(field_number, u32.ValueOrDie(), stream);
+  }
+  return u32.status();
+}
+
+// Writes an INT64 field, including tag, to the stream.
+inline Status WriteInt64(int field_number, const DataPiece& data,
+                         CodedOutputStream* stream) {
+  StatusOr<int64> i64 = data.ToInt64();
+  if (i64.ok()) {
+    WireFormatLite::WriteInt64(field_number, i64.ValueOrDie(), stream);
+  }
+  return i64.status();
+}
+
+// Writes an SFIXED64 field, including tag, to the stream.
+inline Status WriteSFixed64(int field_number, const DataPiece& data,
+                            CodedOutputStream* stream) {
+  StatusOr<int64> i64 = data.ToInt64();
+  if (i64.ok()) {
+    WireFormatLite::WriteSFixed64(field_number, i64.ValueOrDie(), stream);
+  }
+  return i64.status();
+}
+
+// Writes an SINT64 field, including tag, to the stream.
+inline Status WriteSInt64(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<int64> i64 = data.ToInt64();
+  if (i64.ok()) {
+    WireFormatLite::WriteSInt64(field_number, i64.ValueOrDie(), stream);
+  }
+  return i64.status();
+}
+
+// Writes a FIXED64 field, including tag, to the stream.
+inline Status WriteFixed64(int field_number, const DataPiece& data,
+                           CodedOutputStream* stream) {
+  StatusOr<uint64> u64 = data.ToUint64();
+  if (u64.ok()) {
+    WireFormatLite::WriteFixed64(field_number, u64.ValueOrDie(), stream);
+  }
+  return u64.status();
+}
+
+// Writes a UINT64 field, including tag, to the stream.
+inline Status WriteUInt64(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<uint64> u64 = data.ToUint64();
+  if (u64.ok()) {
+    WireFormatLite::WriteUInt64(field_number, u64.ValueOrDie(), stream);
+  }
+  return u64.status();
+}
+
+// Writes a DOUBLE field, including tag, to the stream.
+inline Status WriteDouble(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<double> d = data.ToDouble();
+  if (d.ok()) {
+    WireFormatLite::WriteDouble(field_number, d.ValueOrDie(), stream);
+  }
+  return d.status();
+}
+
+// Writes a FLOAT field, including tag, to the stream.
+inline Status WriteFloat(int field_number, const DataPiece& data,
+                         CodedOutputStream* stream) {
+  StatusOr<float> f = data.ToFloat();
+  if (f.ok()) {
+    WireFormatLite::WriteFloat(field_number, f.ValueOrDie(), stream);
+  }
+  return f.status();
+}
+
+// Writes a BOOL field, including tag, to the stream.
+inline Status WriteBool(int field_number, const DataPiece& data,
+                        CodedOutputStream* stream) {
+  StatusOr<bool> b = data.ToBool();
+  if (b.ok()) {
+    WireFormatLite::WriteBool(field_number, b.ValueOrDie(), stream);
+  }
+  return b.status();
+}
+
+// Writes a BYTES field, including tag, to the stream.
+inline Status WriteBytes(int field_number, const DataPiece& data,
+                         CodedOutputStream* stream) {
+  StatusOr<string> c = data.ToBytes();
+  if (c.ok()) {
+    WireFormatLite::WriteBytes(field_number, c.ValueOrDie(), stream);
+  }
+  return c.status();
+}
+
+// Writes a STRING field, including tag, to the stream.
+inline Status WriteString(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<string> s = data.ToString();
+  if (s.ok()) {
+    WireFormatLite::WriteString(field_number, s.ValueOrDie(), stream);
+  }
+  return s.status();
+}
+
+// Writes an ENUM field, including tag, to the stream.
+inline Status WriteEnum(int field_number, const DataPiece& data,
+                        const google::protobuf::Enum* enum_type,
+                        CodedOutputStream* stream) {
+  StatusOr<int> e = data.ToEnum(enum_type);
+  if (e.ok()) {
+    WireFormatLite::WriteEnum(field_number, e.ValueOrDie(), stream);
+  }
+  return e.status();
+}
+
+// Given a google::protobuf::Type, returns the set of all required fields.
+std::set<const google::protobuf::Field*> GetRequiredFields(
+    const google::protobuf::Type& type) {
+  std::set<const google::protobuf::Field*> required;
+  for (int i = 0; i < type.fields_size(); i++) {
+    const google::protobuf::Field& field = type.fields(i);
+    if (field.cardinality() ==
+        google::protobuf::Field_Cardinality_CARDINALITY_REQUIRED) {
+      required.insert(&field);
+    }
+  }
+  return required;
+}
+
+}  // namespace
+
+ProtoWriter::ProtoElement::ProtoElement(const TypeInfo* typeinfo,
+                                        const google::protobuf::Type& type,
+                                        ProtoWriter* enclosing)
+    : BaseElement(NULL),
+      ow_(enclosing),
+      parent_field_(NULL),
+      typeinfo_(typeinfo),
+      type_(type),
+      required_fields_(GetRequiredFields(type)),
+      size_index_(-1),
+      array_index_(-1) {}
+
+ProtoWriter::ProtoElement::ProtoElement(ProtoWriter::ProtoElement* parent,
+                                        const google::protobuf::Field* field,
+                                        const google::protobuf::Type& type,
+                                        bool is_list)
+    : BaseElement(parent),
+      ow_(this->parent()->ow_),
+      parent_field_(field),
+      typeinfo_(this->parent()->typeinfo_),
+      type_(type),
+      size_index_(
+          !is_list && field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE
+              ? ow_->size_insert_.size()
+              : -1),
+      array_index_(is_list ? 0 : -1) {
+  if (!is_list) {
+    if (ow_->IsRepeated(*field)) {
+      // Update array_index_ if it is an explicit list.
+      if (this->parent()->array_index_ >= 0) this->parent()->array_index_++;
+    } else {
+      this->parent()->RegisterField(field);
+    }
+
+    if (field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE) {
+      required_fields_ = GetRequiredFields(type_);
+      int start_pos = ow_->stream_->ByteCount();
+      // length of serialized message is the final buffer position minus
+      // starting buffer position, plus length adjustments for size fields
+      // of any nested messages. We start with -start_pos here, so we only
+      // need to add the final buffer position to it at the end.
+      SizeInfo info = {start_pos, -start_pos};
+      ow_->size_insert_.push_back(info);
+    }
+  }
+}
+
+ProtoWriter::ProtoElement* ProtoWriter::ProtoElement::pop() {
+  // Calls the registered error listener for any required field(s) not yet
+  // seen.
+  for (set<const google::protobuf::Field*>::iterator it =
+           required_fields_.begin();
+       it != required_fields_.end(); ++it) {
+    ow_->MissingField((*it)->name());
+  }
+  // Computes the total number of proto bytes used by a message, also adjusts
+  // the size of all parent messages by the length of this size field.
+  // If size_index_ < 0, this is not a message, so no size field is added.
+  if (size_index_ >= 0) {
+    // Add the final buffer position to compute the total length of this
+    // serialized message. The stored value (before this addition) already
+    // contains the total length of the size fields of all nested messages
+    // minus the initial buffer position.
+    ow_->size_insert_[size_index_].size += ow_->stream_->ByteCount();
+    // Calculate the length required to serialize the size field of the
+    // message, and propagate this additional size information upward to
+    // all enclosing messages.
+    int size = ow_->size_insert_[size_index_].size;
+    int length = CodedOutputStream::VarintSize32(size);
+    for (ProtoElement* e = parent(); e != NULL; e = e->parent()) {
+      // Only nested messages have size field, lists do not have size field.
+      if (e->size_index_ >= 0) {
+        ow_->size_insert_[e->size_index_].size += length;
+      }
+    }
+  }
+  return BaseElement::pop<ProtoElement>();
+}
+
+void ProtoWriter::ProtoElement::RegisterField(
+    const google::protobuf::Field* field) {
+  if (!required_fields_.empty() &&
+      field->cardinality() ==
+          google::protobuf::Field_Cardinality_CARDINALITY_REQUIRED) {
+    required_fields_.erase(field);
+  }
+}
+
+string ProtoWriter::ProtoElement::ToString() const {
+  if (parent() == NULL) return "";
+  string loc = parent()->ToString();
+  if (!ow_->IsRepeated(*parent_field_) ||
+      parent()->parent_field_ != parent_field_) {
+    string name = parent_field_->name();
+    int i = 0;
+    while (i < name.size() && (ascii_isalnum(name[i]) || name[i] == '_')) ++i;
+    if (i > 0 && i == name.size()) {  // safe field name
+      if (loc.empty()) {
+        loc = name;
+      } else {
+        StrAppend(&loc, ".", name);
+      }
+    } else {
+      StrAppend(&loc, "[\"", CEscape(name), "\"]");
+    }
+  }
+  if (ow_->IsRepeated(*parent_field_) && array_index_ > 0) {
+    StrAppend(&loc, "[", array_index_ - 1, "]");
+  }
+  return loc.empty() ? "." : loc;
+}
+
+bool ProtoWriter::ProtoElement::IsOneofIndexTaken(int32 index) {
+  return ContainsKey(oneof_indices_, index);
+}
+
+void ProtoWriter::ProtoElement::TakeOneofIndex(int32 index) {
+  InsertIfNotPresent(&oneof_indices_, index);
+}
+
+void ProtoWriter::InvalidName(StringPiece unknown_name, StringPiece message) {
+  listener_->InvalidName(location(), ToSnakeCase(unknown_name), message);
+}
+
+void ProtoWriter::InvalidValue(StringPiece type_name, StringPiece value) {
+  listener_->InvalidValue(location(), type_name, value);
+}
+
+void ProtoWriter::MissingField(StringPiece missing_name) {
+  listener_->MissingField(location(), missing_name);
+}
+
+ProtoWriter* ProtoWriter::StartObject(StringPiece name) {
+  // Starting the root message. Create the root ProtoElement and return.
+  if (element_ == NULL) {
+    if (!name.empty()) {
+      InvalidName(name, "Root element should not be named.");
+    }
+    element_.reset(new ProtoElement(typeinfo_, master_type_, this));
+    return this;
+  }
+
+  const google::protobuf::Field* field = NULL;
+  field = BeginNamed(name, false);
+  if (field == NULL) return this;
+
+  // Check to see if this field is a oneof and that no oneof in that group has
+  // already been set.
+  if (!ValidOneof(*field, name)) {
+    ++invalid_depth_;
+    return this;
+  }
+
+  const google::protobuf::Type* type = LookupType(field);
+  if (type == NULL) {
+    ++invalid_depth_;
+    InvalidName(name,
+                StrCat("Missing descriptor for field: ", field->type_url()));
+    return this;
+  }
+
+    WriteTag(*field);
+  element_.reset(new ProtoElement(element_.release(), field, *type, false));
+  return this;
+}
+
+ProtoWriter* ProtoWriter::EndObject() {
+  if (invalid_depth_ > 0) {
+    --invalid_depth_;
+    return this;
+  }
+
+  if (element_ != NULL) {
+    element_.reset(element_->pop());
+  }
+
+
+  // If ending the root element,
+  // then serialize the full message with calculated sizes.
+  if (element_ == NULL) {
+    WriteRootMessage();
+  }
+  return this;
+}
+
+ProtoWriter* ProtoWriter::StartList(StringPiece name) {
+  const google::protobuf::Field* field = BeginNamed(name, true);
+  if (field == NULL) return this;
+
+  if (!ValidOneof(*field, name)) {
+    ++invalid_depth_;
+    return this;
+  }
+
+  const google::protobuf::Type* type = LookupType(field);
+  if (type == NULL) {
+    ++invalid_depth_;
+    InvalidName(name,
+                StrCat("Missing descriptor for field: ", field->type_url()));
+    return this;
+  }
+
+  element_.reset(new ProtoElement(element_.release(), field, *type, true));
+  return this;
+}
+
+ProtoWriter* ProtoWriter::EndList() {
+  if (invalid_depth_ > 0) {
+    --invalid_depth_;
+  } else if (element_ != NULL) {
+    element_.reset(element_->pop());
+  }
+  return this;
+}
+
+ProtoWriter* ProtoWriter::RenderDataPiece(StringPiece name,
+                                          const DataPiece& data) {
+  Status status;
+  if (invalid_depth_ > 0) return this;
+
+  const google::protobuf::Field* field = Lookup(name);
+  if (field == NULL) return this;
+
+  if (!ValidOneof(*field, name)) return this;
+
+  const google::protobuf::Type* type = LookupType(field);
+  if (type == NULL) {
+    InvalidName(name,
+                StrCat("Missing descriptor for field: ", field->type_url()));
+    return this;
+  }
+
+  // Pushing a ProtoElement and then pop it off at the end for 2 purposes:
+  // error location reporting and required field accounting.
+  element_.reset(new ProtoElement(element_.release(), field, *type, false));
+
+  if (field->kind() == google::protobuf::Field_Kind_TYPE_UNKNOWN ||
+      field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE) {
+    InvalidValue(field->type_url().empty()
+                     ? google::protobuf::Field_Kind_Name(field->kind())
+                     : field->type_url(),
+                 data.ValueAsStringOrDefault(""));
+    element_.reset(element()->pop());
+    return this;
+  }
+
+  switch (field->kind()) {
+    case google::protobuf::Field_Kind_TYPE_INT32: {
+      status = WriteInt32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SFIXED32: {
+      status = WriteSFixed32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SINT32: {
+      status = WriteSInt32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FIXED32: {
+      status = WriteFixed32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_UINT32: {
+      status = WriteUInt32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_INT64: {
+      status = WriteInt64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SFIXED64: {
+      status = WriteSFixed64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SINT64: {
+      status = WriteSInt64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FIXED64: {
+      status = WriteFixed64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_UINT64: {
+      status = WriteUInt64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_DOUBLE: {
+      status = WriteDouble(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FLOAT: {
+      status = WriteFloat(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_BOOL: {
+      status = WriteBool(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_BYTES: {
+      status = WriteBytes(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_STRING: {
+      status = WriteString(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_ENUM: {
+      status = WriteEnum(field->number(), data,
+                         typeinfo_->GetEnumByTypeUrl(field->type_url()),
+                         stream_.get());
+      break;
+    }
+    default:  // TYPE_GROUP or TYPE_MESSAGE
+      status = Status(INVALID_ARGUMENT, data.ToString().ValueOrDie());
+  }
+
+  if (!status.ok()) {
+    InvalidValue(google::protobuf::Field_Kind_Name(field->kind()),
+                 status.error_message());
+  }
+
+  element_.reset(element()->pop());
+  return this;
+}
+
+bool ProtoWriter::ValidOneof(const google::protobuf::Field& field,
+                             StringPiece unnormalized_name) {
+  if (element_ == NULL) return true;
+
+  if (field.oneof_index() > 0) {
+    if (element_->IsOneofIndexTaken(field.oneof_index())) {
+      InvalidValue(
+          "oneof",
+          StrCat("oneof field '",
+                 element_->type().oneofs(field.oneof_index() - 1),
+                 "' is already set. Cannot set '", unnormalized_name, "'"));
+      return false;
+    }
+    element_->TakeOneofIndex(field.oneof_index());
+  }
+  return true;
+}
+
+bool ProtoWriter::IsRepeated(const google::protobuf::Field& field) {
+  return field.cardinality() ==
+         google::protobuf::Field_Cardinality_CARDINALITY_REPEATED;
+}
+
+const google::protobuf::Field* ProtoWriter::BeginNamed(StringPiece name,
+                                                       bool is_list) {
+  if (invalid_depth_ > 0) {
+    ++invalid_depth_;
+    return NULL;
+  }
+  const google::protobuf::Field* field = Lookup(name);
+  if (field == NULL) {
+    ++invalid_depth_;
+    // InvalidName() already called in Lookup().
+    return NULL;
+  }
+  if (is_list && !IsRepeated(*field)) {
+    ++invalid_depth_;
+    InvalidName(name, "Proto field is not repeating, cannot start list.");
+    return NULL;
+  }
+  return field;
+}
+
+const google::protobuf::Field* ProtoWriter::Lookup(
+    StringPiece unnormalized_name) {
+  ProtoElement* e = element();
+  if (e == NULL) {
+    InvalidName(unnormalized_name, "Root element must be a message.");
+    return NULL;
+  }
+  if (unnormalized_name.empty()) {
+    // Objects in repeated field inherit the same field descriptor.
+    if (e->parent_field() == NULL) {
+      InvalidName(unnormalized_name, "Proto fields must have a name.");
+    } else if (!IsRepeated(*e->parent_field())) {
+      InvalidName(unnormalized_name, "Proto fields must have a name.");
+      return NULL;
+    }
+    return e->parent_field();
+  }
+  const google::protobuf::Field* field =
+      typeinfo_->FindField(&e->type(), unnormalized_name);
+  if (field == NULL) InvalidName(unnormalized_name, "Cannot find field.");
+  return field;
+}
+
+const google::protobuf::Type* ProtoWriter::LookupType(
+    const google::protobuf::Field* field) {
+  return ((field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE ||
+           field->kind() == google::protobuf::Field_Kind_TYPE_GROUP)
+              ? typeinfo_->GetTypeByTypeUrl(field->type_url())
+              : &element_->type());
+}
+
+void ProtoWriter::WriteRootMessage() {
+  GOOGLE_DCHECK(!done_);
+  int curr_pos = 0;
+  // Calls the destructor of CodedOutputStream to remove any uninitialized
+  // memory from the Cord before we read it.
+  stream_.reset(NULL);
+  const void* data;
+  int length;
+  google::protobuf::io::ArrayInputStream input_stream(buffer_.data(), buffer_.size());
+  while (input_stream.Next(&data, &length)) {
+    if (length == 0) continue;
+    int num_bytes = length;
+    // Write up to where we need to insert the size field.
+    // The number of bytes we may write is the smaller of:
+    //   - the current fragment size
+    //   - the distance to the next position where a size field needs to be
+    //     inserted.
+    if (!size_insert_.empty() &&
+        size_insert_.front().pos - curr_pos < num_bytes) {
+      num_bytes = size_insert_.front().pos - curr_pos;
+    }
+    output_->Append(static_cast<const char*>(data), num_bytes);
+    if (num_bytes < length) {
+      input_stream.BackUp(length - num_bytes);
+    }
+    curr_pos += num_bytes;
+    // Insert the size field.
+    //   size_insert_.front():      the next <index, size> pair to be written.
+    //   size_insert_.front().pos:  position of the size field.
+    //   size_insert_.front().size: the size (integer) to be inserted.
+    if (!size_insert_.empty() && curr_pos == size_insert_.front().pos) {
+      // Varint32 occupies at most 10 bytes.
+      uint8 insert_buffer[10];
+      uint8* insert_buffer_pos = CodedOutputStream::WriteVarint32ToArray(
+          size_insert_.front().size, insert_buffer);
+      output_->Append(reinterpret_cast<const char*>(insert_buffer),
+                      insert_buffer_pos - insert_buffer);
+      size_insert_.pop_front();
+    }
+  }
+  output_->Flush();
+  stream_.reset(new CodedOutputStream(&adapter_));
+  done_ = true;
+}
+
+void ProtoWriter::WriteTag(const google::protobuf::Field& field) {
+  WireFormatLite::WireType wire_type = WireFormatLite::WireTypeForFieldType(
+      static_cast<WireFormatLite::FieldType>(field.kind()));
+  stream_->WriteTag(WireFormatLite::MakeTag(field.number(), wire_type));
+}
+
+
+}  // namespace converter
+}  // namespace util
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/util/internal/proto_writer.h b/src/google/protobuf/util/internal/proto_writer.h
new file mode 100644
index 00000000..e631e56f
--- /dev/null
+++ b/src/google/protobuf/util/internal/proto_writer.h
@@ -0,0 +1,315 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef GOOGLE_PROTOBUF_UTIL_CONVERTER_PROTO_WRITER_H__
+#define GOOGLE_PROTOBUF_UTIL_CONVERTER_PROTO_WRITER_H__
+
+#include <deque>
+#include <google/protobuf/stubs/hash.h>
+#include <string>
+
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/io/coded_stream.h>
+#include <google/protobuf/io/zero_copy_stream_impl.h>
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/util/internal/type_info.h>
+#include <google/protobuf/util/internal/datapiece.h>
+#include <google/protobuf/util/internal/error_listener.h>
+#include <google/protobuf/util/internal/structured_objectwriter.h>
+#include <google/protobuf/util/type_resolver.h>
+#include <google/protobuf/stubs/bytestream.h>
+
+namespace google {
+namespace protobuf {
+namespace io {
+class CodedOutputStream;
+}  // namespace io
+}  // namespace protobuf
+
+
+namespace protobuf {
+class Type;
+class Field;
+}  // namespace protobuf
+
+
+namespace protobuf {
+namespace util {
+namespace converter {
+
+class ObjectLocationTracker;
+
+// An ObjectWriter that can write protobuf bytes directly from writer events.
+// This class does not support special types like Struct or Map. However, since
+// this class supports raw protobuf, it can be used to provide support for
+// special types by inheriting from it or by wrapping it.
+//
+// It also supports streaming.
+class LIBPROTOBUF_EXPORT ProtoWriter : public StructuredObjectWriter {
+ public:
+// Constructor. Does not take ownership of any parameter passed in.
+  ProtoWriter(TypeResolver* type_resolver, const google::protobuf::Type& type,
+              strings::ByteSink* output, ErrorListener* listener);
+  virtual ~ProtoWriter();
+
+  // ObjectWriter methods.
+  virtual ProtoWriter* StartObject(StringPiece name);
+  virtual ProtoWriter* EndObject();
+  virtual ProtoWriter* StartList(StringPiece name);
+  virtual ProtoWriter* EndList();
+  virtual ProtoWriter* RenderBool(StringPiece name, bool value) {
+    return RenderDataPiece(name, DataPiece(value));
+  }
+  virtual ProtoWriter* RenderInt32(StringPiece name, int32 value) {
+    return RenderDataPiece(name, DataPiece(value));
+  }
+  virtual ProtoWriter* RenderUint32(StringPiece name, uint32 value) {
+    return RenderDataPiece(name, DataPiece(value));
+  }
+  virtual ProtoWriter* RenderInt64(StringPiece name, int64 value) {
+    return RenderDataPiece(name, DataPiece(value));
+  }
+  virtual ProtoWriter* RenderUint64(StringPiece name, uint64 value) {
+    return RenderDataPiece(name, DataPiece(value));
+  }
+  virtual ProtoWriter* RenderDouble(StringPiece name, double value) {
+    return RenderDataPiece(name, DataPiece(value));
+  }
+  virtual ProtoWriter* RenderFloat(StringPiece name, float value) {
+    return RenderDataPiece(name, DataPiece(value));
+  }
+  virtual ProtoWriter* RenderString(StringPiece name, StringPiece value) {
+    return RenderDataPiece(name, DataPiece(value));
+  }
+  virtual ProtoWriter* RenderBytes(StringPiece name, StringPiece value) {
+    return RenderDataPiece(name, DataPiece(value, false));
+  }
+  virtual ProtoWriter* RenderNull(StringPiece name) {
+    return RenderDataPiece(name, DataPiece::NullData());
+  }
+
+  // Renders a DataPiece 'value' into a field whose wire type is determined
+  // from the given field 'name'.
+  virtual ProtoWriter* RenderDataPiece(StringPiece name,
+                                       const DataPiece& value);
+
+  // Returns the location tracker to use for tracking locations for errors.
+  const LocationTrackerInterface& location() {
+    return element_ != NULL ? *element_ : *tracker_;
+  }
+
+  // When true, we finished writing to output a complete message.
+  bool done() const { return done_; }
+
+  // Returns the proto stream object.
+  google::protobuf::io::CodedOutputStream* stream() { return stream_.get(); }
+
+  // Getters and mutators of invalid_depth_.
+  void IncrementInvalidDepth() { ++invalid_depth_; }
+  void DecrementInvalidDepth() { --invalid_depth_; }
+  int invalid_depth() { return invalid_depth_; }
+
+  ErrorListener* listener() { return listener_; }
+
+  const TypeInfo* typeinfo() { return typeinfo_; }
+
+ protected:
+  class LIBPROTOBUF_EXPORT ProtoElement : public BaseElement, public LocationTrackerInterface {
+   public:
+    // Constructor for the root element. No parent nor field.
+    ProtoElement(const TypeInfo* typeinfo, const google::protobuf::Type& type,
+                 ProtoWriter* enclosing);
+
+    // Constructor for a field of an element.
+    ProtoElement(ProtoElement* parent, const google::protobuf::Field* field,
+                 const google::protobuf::Type& type, bool is_list);
+
+    virtual ~ProtoElement() {}
+
+    // Called just before the destructor for clean up:
+    //   - reports any missing required fields
+    //   - computes the space needed by the size field, and augment the
+    //     length of all parent messages by this additional space.
+    //   - releases and returns the parent pointer.
+    ProtoElement* pop();
+
+    // Accessors
+    // parent_field() may be NULL if we are at root.
+    const google::protobuf::Field* parent_field() const {
+      return parent_field_;
+    }
+    const google::protobuf::Type& type() const { return type_; }
+
+    // Registers field for accounting required fields.
+    void RegisterField(const google::protobuf::Field* field);
+
+    // To report location on error messages.
+    virtual string ToString() const;
+
+    virtual ProtoElement* parent() const {
+      return static_cast<ProtoElement*>(BaseElement::parent());
+    }
+
+    // Returns true if the index is already taken by a preceeding oneof input.
+    bool IsOneofIndexTaken(int32 index);
+
+    // Marks the oneof 'index' as taken. Future inputs to this oneof will
+    // generate an error.
+    void TakeOneofIndex(int32 index);
+
+   private:
+    // Used for access to variables of the enclosing instance of
+    // ProtoWriter.
+    ProtoWriter* ow_;
+
+    // Describes the element as a field in the parent message.
+    // parent_field_ is NULL if and only if this element is the root element.
+    const google::protobuf::Field* parent_field_;
+
+    // TypeInfo to lookup types.
+    const TypeInfo* typeinfo_;
+
+    // Additional variables if this element is a message:
+    // (Root element is always a message).
+    // type_             : the type of this element.
+    // required_fields_  : set of required fields.
+    // size_index_       : index into ProtoWriter::size_insert_
+    //                     for later insertion of serialized message length.
+    const google::protobuf::Type& type_;
+    std::set<const google::protobuf::Field*> required_fields_;
+    const int size_index_;
+
+    // Tracks position in repeated fields, needed for LocationTrackerInterface.
+    int array_index_;
+
+    // Set of oneof indices already seen for the type_. Used to validate
+    // incoming messages so no more than one oneof is set.
+    hash_set<int32> oneof_indices_;
+
+    GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS(ProtoElement);
+  };
+
+  // Container for inserting 'size' information at the 'pos' position.
+  struct SizeInfo {
+    const int pos;
+    int size;
+  };
+
+  ProtoWriter(const TypeInfo* typeinfo, const google::protobuf::Type& type,
+              strings::ByteSink* output, ErrorListener* listener);
+
+  virtual ProtoElement* element() { return element_.get(); }
+
+  // Helper methods for calling ErrorListener. See error_listener.h.
+  void InvalidName(StringPiece unknown_name, StringPiece message);
+  void InvalidValue(StringPiece type_name, StringPiece value);
+  void MissingField(StringPiece missing_name);
+
+  // Common code for BeginObject() and BeginList() that does invalid_depth_
+  // bookkeeping associated with name lookup.
+  const google::protobuf::Field* BeginNamed(StringPiece name, bool is_list);
+
+  // Lookup the field in the current element. Looks in the base descriptor
+  // and in any extension. This will report an error if the field cannot be
+  // found or if multiple matching extensions are found.
+  const google::protobuf::Field* Lookup(StringPiece name);
+
+  // Lookup the field type in the type descriptor. Returns NULL if the type
+  // is not known.
+  const google::protobuf::Type* LookupType(
+      const google::protobuf::Field* field);
+
+  // Write serialized output to the final output ByteSink, inserting all
+  // the size information for nested messages that are missing from the
+  // intermediate Cord buffer.
+  void WriteRootMessage();
+
+  // Helper method to write proto tags based on the given field.
+  void WriteTag(const google::protobuf::Field& field);
+
+
+  // Returns true if the field for type_ can be set as a oneof. If field is not
+  // a oneof type, this function does nothing and returns true.
+  // If another field for this oneof is already set, this function returns
+  // false. It also calls the appropriate error callback.
+  // unnormalized_name is used for error string.
+  bool ValidOneof(const google::protobuf::Field& field,
+                  StringPiece unnormalized_name);
+
+  // Returns true if the field is repeated.
+  bool IsRepeated(const google::protobuf::Field& field);
+
+ private:
+  // Variables for describing the structure of the input tree:
+  // master_type_: descriptor for the whole protobuf message.
+  // typeinfo_ : the TypeInfo object to lookup types.
+  const google::protobuf::Type& master_type_;
+  const TypeInfo* typeinfo_;
+  // Whether we own the typeinfo_ object.
+  bool own_typeinfo_;
+
+  // Indicates whether we finished writing root message completely.
+  bool done_;
+
+  // Variable for internal state processing:
+  // element_    : the current element.
+  // size_insert_: sizes of nested messages.
+  //               pos  - position to insert the size field.
+  //               size - size value to be inserted.
+  google::protobuf::scoped_ptr<ProtoElement> element_;
+  std::deque<SizeInfo> size_insert_;
+
+  // Variables for output generation:
+  // output_  : pointer to an external ByteSink for final user-visible output.
+  // buffer_  : buffer holding partial message before being ready for output_.
+  // adapter_ : internal adapter between CodedOutputStream and buffer_.
+  // stream_  : wrapper for writing tags and other encodings in wire format.
+  strings::ByteSink* output_;
+  string buffer_;
+  google::protobuf::io::StringOutputStream adapter_;
+  google::protobuf::scoped_ptr<google::protobuf::io::CodedOutputStream> stream_;
+
+  // Variables for error tracking and reporting:
+  // listener_     : a place to report any errors found.
+  // invalid_depth_: number of enclosing invalid nested messages.
+  // tracker_      : the root location tracker interface.
+  ErrorListener* listener_;
+  int invalid_depth_;
+  google::protobuf::scoped_ptr<LocationTrackerInterface> tracker_;
+
+  GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS(ProtoWriter);
+};
+
+}  // namespace converter
+}  // namespace util
+}  // namespace protobuf
+
+}  // namespace google
+#endif  // GOOGLE_PROTOBUF_UTIL_CONVERTER_PROTO_WRITER_H__
diff --git a/src/google/protobuf/util/internal/protostream_objectsource.cc b/src/google/protobuf/util/internal/protostream_objectsource.cc
index 2bbb1597..034d616f 100644
--- a/src/google/protobuf/util/internal/protostream_objectsource.cc
+++ b/src/google/protobuf/util/internal/protostream_objectsource.cc
@@ -140,10 +140,10 @@ Status ProtoStreamObjectSource::WriteMessage(const google::protobuf::Type& type,
                                              bool include_start_and_end,
                                              ObjectWriter* ow) const {
 
-  const TypeRenderer* type_renderer = FindTypeRenderer(type.name());
-  if (type_renderer != NULL) {
-    return (*type_renderer)(this, type, name, ow);
-  }
+    const TypeRenderer* type_renderer = FindTypeRenderer(type.name());
+    if (type_renderer != NULL) {
+      return (*type_renderer)(this, type, name, ow);
+    }
 
   const google::protobuf::Field* field = NULL;
   string field_name;
@@ -171,7 +171,9 @@ Status ProtoStreamObjectSource::WriteMessage(const google::protobuf::Type& type,
 
     if (field->cardinality() ==
         google::protobuf::Field_Cardinality_CARDINALITY_REPEATED) {
-      if (IsMap(*field)) {
+      bool check_maps = true;
+
+      if (check_maps && IsMap(*field)) {
         ow->StartObject(field_name);
         ASSIGN_OR_RETURN(tag, RenderMap(field, field_name, tag, ow));
         ow->EndObject();
@@ -218,48 +220,32 @@ StatusOr<uint32> ProtoStreamObjectSource::RenderMap(
   const google::protobuf::Type* field_type =
       typeinfo_->GetTypeByTypeUrl(field->type_url());
   uint32 tag_to_return = 0;
-  if (IsPackable(*field) &&
-      list_tag ==
-          WireFormatLite::MakeTag(field->number(),
-                                  WireFormatLite::WIRETYPE_LENGTH_DELIMITED)) {
-    RETURN_IF_ERROR(RenderPackedMapEntry(field_type, ow));
-    tag_to_return = stream_->ReadTag();
-  } else {
-    do {
-      RETURN_IF_ERROR(RenderMapEntry(field_type, ow));
-    } while ((tag_to_return = stream_->ReadTag()) == list_tag);
-  }
-  return tag_to_return;
-}
-
-Status ProtoStreamObjectSource::RenderMapEntry(
-    const google::protobuf::Type* type, ObjectWriter* ow) const {
-  uint32 buffer32;
-  stream_->ReadVarint32(&buffer32);  // message length
-  int old_limit = stream_->PushLimit(buffer32);
-  string map_key;
-  for (uint32 tag = stream_->ReadTag(); tag != 0; tag = stream_->ReadTag()) {
-    const google::protobuf::Field* field = FindAndVerifyField(*type, tag);
-    if (field == NULL) {
-      WireFormat::SkipField(stream_, tag, NULL);
-      continue;
-    }
-    // Map field numbers are key = 1 and value = 2
-    if (field->number() == 1) {
-      map_key = ReadFieldValueAsString(*field);
-    } else if (field->number() == 2) {
-      if (map_key.empty()) {
-        return Status(util::error::INTERNAL, "Map key must be non-empty");
+  do {
+    // Render map entry message type.
+    uint32 buffer32;
+    stream_->ReadVarint32(&buffer32);  // message length
+    int old_limit = stream_->PushLimit(buffer32);
+    string map_key;
+    for (uint32 tag = stream_->ReadTag(); tag != 0; tag = stream_->ReadTag()) {
+      const google::protobuf::Field* field =
+          FindAndVerifyField(*field_type, tag);
+      if (field == NULL) {
+        WireFormat::SkipField(stream_, tag, NULL);
+        continue;
+      }
+      // Map field numbers are key = 1 and value = 2
+      if (field->number() == 1) {
+        map_key = ReadFieldValueAsString(*field);
+      } else if (field->number() == 2) {
+        if (map_key.empty()) {
+          return Status(util::error::INTERNAL, "Map key must be non-empty");
+        }
+        RETURN_IF_ERROR(RenderField(field, map_key, ow));
       }
-      // Disable case normalization for map keys as they are just data. We
-      // retain them intact.
-      ow->DisableCaseNormalizationForNextKey();
-      RETURN_IF_ERROR(RenderField(field, map_key, ow));
     }
-  }
-  stream_->PopLimit(old_limit);
-
-  return Status::OK;
+    stream_->PopLimit(old_limit);
+  } while ((tag_to_return = stream_->ReadTag()) == list_tag);
+  return tag_to_return;
 }
 
 Status ProtoStreamObjectSource::RenderPacked(
@@ -274,18 +260,6 @@ Status ProtoStreamObjectSource::RenderPacked(
   return Status::OK;
 }
 
-Status ProtoStreamObjectSource::RenderPackedMapEntry(
-    const google::protobuf::Type* type, ObjectWriter* ow) const {
-  uint32 length;
-  stream_->ReadVarint32(&length);
-  int old_limit = stream_->PushLimit(length);
-  while (stream_->BytesUntilLimit() > 0) {
-    RETURN_IF_ERROR(RenderMapEntry(type, ow));
-  }
-  stream_->PopLimit(old_limit);
-  return Status::OK;
-}
-
 Status ProtoStreamObjectSource::RenderTimestamp(
     const ProtoStreamObjectSource* os, const google::protobuf::Type& type,
     StringPiece field_name, ObjectWriter* ow) {
@@ -601,10 +575,10 @@ Status ProtoStreamObjectSource::RenderAny(const ProtoStreamObjectSource* os,
   // nested_type cannot be null at this time.
   const google::protobuf::Type* nested_type = resolved_type.ValueOrDie();
 
-  // We know the type so we can render it. Recursively parse the nested stream
-  // using a nested ProtoStreamObjectSource using our nested type information.
   google::protobuf::io::ArrayInputStream zero_copy_stream(value.data(), value.size());
   google::protobuf::io::CodedInputStream in_stream(&zero_copy_stream);
+  // We know the type so we can render it. Recursively parse the nested stream
+  // using a nested ProtoStreamObjectSource using our nested type information.
   ProtoStreamObjectSource nested_os(&in_stream, os->typeinfo_, *nested_type);
 
   // We manually call start and end object here so we can inject the @type.
@@ -676,8 +650,7 @@ void ProtoStreamObjectSource::InitRendererMap() {
       &ProtoStreamObjectSource::RenderString;
   (*renderers_)["google.protobuf.BytesValue"] =
       &ProtoStreamObjectSource::RenderBytes;
-  (*renderers_)["google.protobuf.Any"] =
-      &ProtoStreamObjectSource::RenderAny;
+  (*renderers_)["google.protobuf.Any"] = &ProtoStreamObjectSource::RenderAny;
   (*renderers_)["google.protobuf.Struct"] =
       &ProtoStreamObjectSource::RenderStruct;
   (*renderers_)["google.protobuf.Value"] =
@@ -704,87 +677,118 @@ ProtoStreamObjectSource::FindTypeRenderer(const string& type_url) {
 Status ProtoStreamObjectSource::RenderField(
     const google::protobuf::Field* field, StringPiece field_name,
     ObjectWriter* ow) const {
+  // Short-circuit message types as it tends to call WriteMessage recursively
+  // and ends up using a lot of stack space. Keep the stack usage of this
+  // message small in order to preserve stack space and not crash.
+  if (field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE) {
+    uint32 buffer32;
+    stream_->ReadVarint32(&buffer32);  // message length
+    int old_limit = stream_->PushLimit(buffer32);
+    // Get the nested message type for this field.
+    const google::protobuf::Type* type =
+        typeinfo_->GetTypeByTypeUrl(field->type_url());
+    if (type == NULL) {
+      return Status(util::error::INTERNAL,
+                    StrCat("Invalid configuration. Could not find the type: ",
+                           field->type_url()));
+    }
+
+    // Short-circuit any special type rendering to save call-stack space.
+    const TypeRenderer* type_renderer = FindTypeRenderer(type->name());
+
+    bool use_type_renderer = type_renderer != NULL;
+
+    if (use_type_renderer) {
+      RETURN_IF_ERROR((*type_renderer)(this, *type, field_name, ow));
+    } else {
+      RETURN_IF_ERROR(WriteMessage(*type, field_name, 0, true, ow));
+    }
+    if (!stream_->ConsumedEntireMessage()) {
+      return Status(util::error::INVALID_ARGUMENT,
+                    "Nested protocol message not parsed in its entirety.");
+    }
+    stream_->PopLimit(old_limit);
+  } else {
+    // Render all other non-message types.
+    return RenderNonMessageField(field, field_name, ow);
+  }
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderNonMessageField(
+    const google::protobuf::Field* field, StringPiece field_name,
+    ObjectWriter* ow) const {
+  // Temporary buffers of different types.
+  uint32 buffer32;
+  uint64 buffer64;
+  string strbuffer;
   switch (field->kind()) {
     case google::protobuf::Field_Kind_TYPE_BOOL: {
-      uint64 buffer64;
       stream_->ReadVarint64(&buffer64);
       ow->RenderBool(field_name, buffer64 != 0);
       break;
     }
     case google::protobuf::Field_Kind_TYPE_INT32: {
-      uint32 buffer32;
       stream_->ReadVarint32(&buffer32);
       ow->RenderInt32(field_name, bit_cast<int32>(buffer32));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_INT64: {
-      uint64 buffer64;
       stream_->ReadVarint64(&buffer64);
       ow->RenderInt64(field_name, bit_cast<int64>(buffer64));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_UINT32: {
-      uint32 buffer32;
       stream_->ReadVarint32(&buffer32);
       ow->RenderUint32(field_name, bit_cast<uint32>(buffer32));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_UINT64: {
-      uint64 buffer64;
       stream_->ReadVarint64(&buffer64);
       ow->RenderUint64(field_name, bit_cast<uint64>(buffer64));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_SINT32: {
-      uint32 buffer32;
       stream_->ReadVarint32(&buffer32);
       ow->RenderInt32(field_name, WireFormatLite::ZigZagDecode32(buffer32));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_SINT64: {
-      uint64 buffer64;
       stream_->ReadVarint64(&buffer64);
       ow->RenderInt64(field_name, WireFormatLite::ZigZagDecode64(buffer64));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_SFIXED32: {
-      uint32 buffer32;
       stream_->ReadLittleEndian32(&buffer32);
       ow->RenderInt32(field_name, bit_cast<int32>(buffer32));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_SFIXED64: {
-      uint64 buffer64;
       stream_->ReadLittleEndian64(&buffer64);
       ow->RenderInt64(field_name, bit_cast<int64>(buffer64));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_FIXED32: {
-      uint32 buffer32;
       stream_->ReadLittleEndian32(&buffer32);
       ow->RenderUint32(field_name, bit_cast<uint32>(buffer32));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_FIXED64: {
-      uint64 buffer64;
       stream_->ReadLittleEndian64(&buffer64);
       ow->RenderUint64(field_name, bit_cast<uint64>(buffer64));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_FLOAT: {
-      uint32 buffer32;
       stream_->ReadLittleEndian32(&buffer32);
       ow->RenderFloat(field_name, bit_cast<float>(buffer32));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_DOUBLE: {
-      uint64 buffer64;
       stream_->ReadLittleEndian64(&buffer64);
       ow->RenderDouble(field_name, bit_cast<double>(buffer64));
       break;
     }
     case google::protobuf::Field_Kind_TYPE_ENUM: {
-      uint32 buffer32;
       stream_->ReadVarint32(&buffer32);
 
       // If the field represents an explicit NULL value, render null.
@@ -811,40 +815,15 @@ Status ProtoStreamObjectSource::RenderField(
       break;
     }
     case google::protobuf::Field_Kind_TYPE_STRING: {
-      uint32 buffer32;
-      string str;
       stream_->ReadVarint32(&buffer32);  // string size.
-      stream_->ReadString(&str, buffer32);
-      ow->RenderString(field_name, str);
+      stream_->ReadString(&strbuffer, buffer32);
+      ow->RenderString(field_name, strbuffer);
       break;
     }
     case google::protobuf::Field_Kind_TYPE_BYTES: {
-      uint32 buffer32;
       stream_->ReadVarint32(&buffer32);  // bytes size.
-      string value;
-      stream_->ReadString(&value, buffer32);
-      ow->RenderBytes(field_name, value);
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_MESSAGE: {
-      uint32 buffer32;
-      stream_->ReadVarint32(&buffer32);  // message length
-      int old_limit = stream_->PushLimit(buffer32);
-      // Get the nested message type for this field.
-      const google::protobuf::Type* type =
-          typeinfo_->GetTypeByTypeUrl(field->type_url());
-      if (type == NULL) {
-        return Status(util::error::INTERNAL,
-                      StrCat("Invalid configuration. Could not find the type: ",
-                             field->type_url()));
-      }
-
-      RETURN_IF_ERROR(WriteMessage(*type, field_name, 0, true, ow));
-      if (!stream_->ConsumedEntireMessage()) {
-        return Status(util::error::INVALID_ARGUMENT,
-                      "Nested protocol message not parsed in its entirety.");
-      }
-      stream_->PopLimit(old_limit);
+      stream_->ReadString(&strbuffer, buffer32);
+      ow->RenderBytes(field_name, strbuffer);
       break;
     }
     default:
diff --git a/src/google/protobuf/util/internal/protostream_objectsource.h b/src/google/protobuf/util/internal/protostream_objectsource.h
index 3cd37aa1..78defa1d 100644
--- a/src/google/protobuf/util/internal/protostream_objectsource.h
+++ b/src/google/protobuf/util/internal/protostream_objectsource.h
@@ -122,20 +122,12 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectSource : public ObjectSource {
                                      StringPiece name, uint32 list_tag,
                                      ObjectWriter* ow) const;
 
-  // Renders an entry in a map, advancing stream pointers appropriately.
-  util::Status RenderMapEntry(const google::protobuf::Type* type,
-                                ObjectWriter* ow) const;
-
   // Renders a packed repeating field. A packed field is stored as:
   // {tag length item1 item2 item3} instead of the less efficient
   // {tag item1 tag item2 tag item3}.
   util::Status RenderPacked(const google::protobuf::Field* field,
                               ObjectWriter* ow) const;
 
-  // Equivalent of RenderPacked, but for map entries.
-  util::Status RenderPackedMapEntry(const google::protobuf::Type* type,
-                                      ObjectWriter* ow) const;
-
   // Renders a google.protobuf.Timestamp value to ObjectWriter
   static util::Status RenderTimestamp(const ProtoStreamObjectSource* os,
                                         const google::protobuf::Type& type,
@@ -210,6 +202,12 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectSource : public ObjectSource {
   util::Status RenderField(const google::protobuf::Field* field,
                              StringPiece field_name, ObjectWriter* ow) const;
 
+  // Same as above but renders all non-message field types. Callers don't call
+  // this function directly. They just use RenderField.
+  util::Status RenderNonMessageField(const google::protobuf::Field* field,
+                                       StringPiece field_name,
+                                       ObjectWriter* ow) const;
+
 
   // Reads field value according to Field spec in 'field' and returns the read
   // value as string. This only works for primitive datatypes (no message
@@ -238,6 +236,7 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectSource : public ObjectSource {
   // google::protobuf::Type of the message source.
   const google::protobuf::Type& type_;
 
+
   GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS(ProtoStreamObjectSource);
 };
 
diff --git a/src/google/protobuf/util/internal/protostream_objectsource_test.cc b/src/google/protobuf/util/internal/protostream_objectsource_test.cc
index f6e5ee7a..561f6763 100644
--- a/src/google/protobuf/util/internal/protostream_objectsource_test.cc
+++ b/src/google/protobuf/util/internal/protostream_objectsource_test.cc
@@ -327,9 +327,16 @@ TEST_P(ProtostreamObjectSourceTest, RepeatingPrimitives) {
   DoTest(primitive, Primitive::descriptor());
 }
 
+TEST_P(ProtostreamObjectSourceTest, CustomJsonName) {
+  Author author;
+  author.set_id(12345);
+
+  ow_.StartObject("")->RenderUint64("@id", 12345)->EndObject();
+  DoTest(author, Author::descriptor());
+}
+
 TEST_P(ProtostreamObjectSourceTest, NestedMessage) {
   Author* author = new Author();
-  author->set_id(101L);
   author->set_name("Tolstoy");
   Book book;
   book.set_title("My Book");
@@ -338,7 +345,6 @@ TEST_P(ProtostreamObjectSourceTest, NestedMessage) {
   ow_.StartObject("")
       ->RenderString("title", "My Book")
       ->StartObject("author")
-      ->RenderUint64("id", bit_cast<uint64>(101LL))
       ->RenderString("name", "Tolstoy")
       ->EndObject()
       ->EndObject();
diff --git a/src/google/protobuf/util/internal/protostream_objectwriter.cc b/src/google/protobuf/util/internal/protostream_objectwriter.cc
index 0958997c..786bf0be 100644
--- a/src/google/protobuf/util/internal/protostream_objectwriter.cc
+++ b/src/google/protobuf/util/internal/protostream_objectwriter.cc
@@ -51,7 +51,6 @@ namespace util {
 namespace converter {
 
 using google::protobuf::internal::WireFormatLite;
-using google::protobuf::io::CodedOutputStream;
 using util::error::INVALID_ARGUMENT;
 using util::Status;
 using util::StatusOr;
@@ -60,230 +59,31 @@ using util::StatusOr;
 ProtoStreamObjectWriter::ProtoStreamObjectWriter(
     TypeResolver* type_resolver, const google::protobuf::Type& type,
     strings::ByteSink* output, ErrorListener* listener)
-    : master_type_(type),
-      typeinfo_(TypeInfo::NewTypeInfo(type_resolver)),
-      own_typeinfo_(true),
-      done_(false),
-      element_(NULL),
-      size_insert_(),
-      output_(output),
-      buffer_(),
-      adapter_(&buffer_),
-      stream_(new CodedOutputStream(&adapter_)),
-      listener_(listener),
-      invalid_depth_(0),
-      tracker_(new ObjectLocationTracker()) {}
+    : ProtoWriter(type_resolver, type, output, listener),
+      master_type_(type),
+      current_(NULL) {}
 
 ProtoStreamObjectWriter::ProtoStreamObjectWriter(
     const TypeInfo* typeinfo, const google::protobuf::Type& type,
     strings::ByteSink* output, ErrorListener* listener)
-    : master_type_(type),
-      typeinfo_(typeinfo),
-      own_typeinfo_(false),
-      done_(false),
-      element_(NULL),
-      size_insert_(),
-      output_(output),
-      buffer_(),
-      adapter_(&buffer_),
-      stream_(new CodedOutputStream(&adapter_)),
-      listener_(listener),
-      invalid_depth_(0),
-      tracker_(new ObjectLocationTracker()) {}
+    : ProtoWriter(typeinfo, type, output, listener),
+      master_type_(type),
+      current_(NULL) {}
 
 ProtoStreamObjectWriter::~ProtoStreamObjectWriter() {
-  if (own_typeinfo_) {
-    delete typeinfo_;
-  }
-  if (element_ == NULL) return;
+  if (current_ == NULL) return;
   // Cleanup explicitly in order to avoid destructor stack overflow when input
   // is deeply nested.
   // Cast to BaseElement to avoid doing additional checks (like missing fields)
   // during pop().
   google::protobuf::scoped_ptr<BaseElement> element(
-      static_cast<BaseElement*>(element_.get())->pop<BaseElement>());
+      static_cast<BaseElement*>(current_.get())->pop<BaseElement>());
   while (element != NULL) {
     element.reset(element->pop<BaseElement>());
   }
 }
 
 namespace {
-
-// Writes an INT32 field, including tag to the stream.
-inline Status WriteInt32(int field_number, const DataPiece& data,
-                         CodedOutputStream* stream) {
-  StatusOr<int32> i32 = data.ToInt32();
-  if (i32.ok()) {
-    WireFormatLite::WriteInt32(field_number, i32.ValueOrDie(), stream);
-  }
-  return i32.status();
-}
-
-// writes an SFIXED32 field, including tag, to the stream.
-inline Status WriteSFixed32(int field_number, const DataPiece& data,
-                            CodedOutputStream* stream) {
-  StatusOr<int32> i32 = data.ToInt32();
-  if (i32.ok()) {
-    WireFormatLite::WriteSFixed32(field_number, i32.ValueOrDie(), stream);
-  }
-  return i32.status();
-}
-
-// Writes an SINT32 field, including tag, to the stream.
-inline Status WriteSInt32(int field_number, const DataPiece& data,
-                          CodedOutputStream* stream) {
-  StatusOr<int32> i32 = data.ToInt32();
-  if (i32.ok()) {
-    WireFormatLite::WriteSInt32(field_number, i32.ValueOrDie(), stream);
-  }
-  return i32.status();
-}
-
-// Writes a FIXED32 field, including tag, to the stream.
-inline Status WriteFixed32(int field_number, const DataPiece& data,
-                           CodedOutputStream* stream) {
-  StatusOr<uint32> u32 = data.ToUint32();
-  if (u32.ok()) {
-    WireFormatLite::WriteFixed32(field_number, u32.ValueOrDie(), stream);
-  }
-  return u32.status();
-}
-
-// Writes a UINT32 field, including tag, to the stream.
-inline Status WriteUInt32(int field_number, const DataPiece& data,
-                          CodedOutputStream* stream) {
-  StatusOr<uint32> u32 = data.ToUint32();
-  if (u32.ok()) {
-    WireFormatLite::WriteUInt32(field_number, u32.ValueOrDie(), stream);
-  }
-  return u32.status();
-}
-
-// Writes an INT64 field, including tag, to the stream.
-inline Status WriteInt64(int field_number, const DataPiece& data,
-                         CodedOutputStream* stream) {
-  StatusOr<int64> i64 = data.ToInt64();
-  if (i64.ok()) {
-    WireFormatLite::WriteInt64(field_number, i64.ValueOrDie(), stream);
-  }
-  return i64.status();
-}
-
-// Writes an SFIXED64 field, including tag, to the stream.
-inline Status WriteSFixed64(int field_number, const DataPiece& data,
-                            CodedOutputStream* stream) {
-  StatusOr<int64> i64 = data.ToInt64();
-  if (i64.ok()) {
-    WireFormatLite::WriteSFixed64(field_number, i64.ValueOrDie(), stream);
-  }
-  return i64.status();
-}
-
-// Writes an SINT64 field, including tag, to the stream.
-inline Status WriteSInt64(int field_number, const DataPiece& data,
-                          CodedOutputStream* stream) {
-  StatusOr<int64> i64 = data.ToInt64();
-  if (i64.ok()) {
-    WireFormatLite::WriteSInt64(field_number, i64.ValueOrDie(), stream);
-  }
-  return i64.status();
-}
-
-// Writes a FIXED64 field, including tag, to the stream.
-inline Status WriteFixed64(int field_number, const DataPiece& data,
-                           CodedOutputStream* stream) {
-  StatusOr<uint64> u64 = data.ToUint64();
-  if (u64.ok()) {
-    WireFormatLite::WriteFixed64(field_number, u64.ValueOrDie(), stream);
-  }
-  return u64.status();
-}
-
-// Writes a UINT64 field, including tag, to the stream.
-inline Status WriteUInt64(int field_number, const DataPiece& data,
-                          CodedOutputStream* stream) {
-  StatusOr<uint64> u64 = data.ToUint64();
-  if (u64.ok()) {
-    WireFormatLite::WriteUInt64(field_number, u64.ValueOrDie(), stream);
-  }
-  return u64.status();
-}
-
-// Writes a DOUBLE field, including tag, to the stream.
-inline Status WriteDouble(int field_number, const DataPiece& data,
-                          CodedOutputStream* stream) {
-  StatusOr<double> d = data.ToDouble();
-  if (d.ok()) {
-    WireFormatLite::WriteDouble(field_number, d.ValueOrDie(), stream);
-  }
-  return d.status();
-}
-
-// Writes a FLOAT field, including tag, to the stream.
-inline Status WriteFloat(int field_number, const DataPiece& data,
-                         CodedOutputStream* stream) {
-  StatusOr<float> f = data.ToFloat();
-  if (f.ok()) {
-    WireFormatLite::WriteFloat(field_number, f.ValueOrDie(), stream);
-  }
-  return f.status();
-}
-
-// Writes a BOOL field, including tag, to the stream.
-inline Status WriteBool(int field_number, const DataPiece& data,
-                        CodedOutputStream* stream) {
-  StatusOr<bool> b = data.ToBool();
-  if (b.ok()) {
-    WireFormatLite::WriteBool(field_number, b.ValueOrDie(), stream);
-  }
-  return b.status();
-}
-
-// Writes a BYTES field, including tag, to the stream.
-inline Status WriteBytes(int field_number, const DataPiece& data,
-                         CodedOutputStream* stream) {
-  StatusOr<string> c = data.ToBytes();
-  if (c.ok()) {
-    WireFormatLite::WriteBytes(field_number, c.ValueOrDie(), stream);
-  }
-  return c.status();
-}
-
-// Writes a STRING field, including tag, to the stream.
-inline Status WriteString(int field_number, const DataPiece& data,
-                          CodedOutputStream* stream) {
-  StatusOr<string> s = data.ToString();
-  if (s.ok()) {
-    WireFormatLite::WriteString(field_number, s.ValueOrDie(), stream);
-  }
-  return s.status();
-}
-
-// Writes an ENUM field, including tag, to the stream.
-inline Status WriteEnum(int field_number, const DataPiece& data,
-                        const google::protobuf::Enum* enum_type,
-                        CodedOutputStream* stream) {
-  StatusOr<int> e = data.ToEnum(enum_type);
-  if (e.ok()) {
-    WireFormatLite::WriteEnum(field_number, e.ValueOrDie(), stream);
-  }
-  return e.status();
-}
-
-// Given a google::protobuf::Type, returns the set of all required fields.
-std::set<const google::protobuf::Field*> GetRequiredFields(
-    const google::protobuf::Type& type) {
-  std::set<const google::protobuf::Field*> required;
-  for (int i = 0; i < type.fields_size(); i++) {
-    const google::protobuf::Field& field = type.fields(i);
-    if (field.cardinality() ==
-        google::protobuf::Field_Cardinality_CARDINALITY_REQUIRED) {
-      required.insert(&field);
-    }
-  }
-  return required;
-}
-
 // Utility method to split a string representation of Timestamp or Duration and
 // return the parts.
 void SplitSecondsAndNanos(StringPiece input, StringPiece* seconds,
@@ -298,6 +98,78 @@ void SplitSecondsAndNanos(StringPiece input, StringPiece* seconds,
   }
 }
 
+Status GetNanosFromStringPiece(StringPiece s_nanos,
+                               const char* parse_failure_message,
+                               const char* exceeded_limit_message,
+                               int32* nanos) {
+  *nanos = 0;
+
+  // Count the number of leading 0s and consume them.
+  int num_leading_zeros = 0;
+  while (s_nanos.Consume("0")) {
+    num_leading_zeros++;
+  }
+  int32 i_nanos = 0;
+  // 's_nanos' contains fractional seconds -- i.e. 'nanos' is equal to
+  // "0." + s_nanos.ToString() seconds. An int32 is used for the
+  // conversion to 'nanos', rather than a double, so that there is no
+  // loss of precision.
+  if (!s_nanos.empty() && !safe_strto32(s_nanos.ToString(), &i_nanos)) {
+    return Status(INVALID_ARGUMENT, parse_failure_message);
+  }
+  if (i_nanos > kNanosPerSecond || i_nanos < 0) {
+    return Status(INVALID_ARGUMENT, exceeded_limit_message);
+  }
+  // s_nanos should only have digits. No whitespace.
+  if (s_nanos.find_first_not_of("0123456789") != StringPiece::npos) {
+    return Status(INVALID_ARGUMENT, parse_failure_message);
+  }
+
+  if (i_nanos > 0) {
+    // 'scale' is the number of digits to the right of the decimal
+    // point in "0." + s_nanos.ToString()
+    int32 scale = num_leading_zeros + s_nanos.size();
+    // 'conversion' converts i_nanos into nanoseconds.
+    // conversion = kNanosPerSecond / static_cast<int32>(std::pow(10, scale))
+    // For efficiency, we precompute the conversion factor.
+    int32 conversion = 0;
+    switch (scale) {
+      case 1:
+        conversion = 100000000;
+        break;
+      case 2:
+        conversion = 10000000;
+        break;
+      case 3:
+        conversion = 1000000;
+        break;
+      case 4:
+        conversion = 100000;
+        break;
+      case 5:
+        conversion = 10000;
+        break;
+      case 6:
+        conversion = 1000;
+        break;
+      case 7:
+        conversion = 100;
+        break;
+      case 8:
+        conversion = 10;
+        break;
+      case 9:
+        conversion = 1;
+        break;
+      default:
+        return Status(INVALID_ARGUMENT, exceeded_limit_message);
+    }
+    *nanos = i_nanos * conversion;
+  }
+
+  return Status::OK;
+}
+
 }  // namespace
 
 ProtoStreamObjectWriter::AnyWriter::AnyWriter(ProtoStreamObjectWriter* parent)
@@ -421,7 +293,7 @@ void ProtoStreamObjectWriter::AnyWriter::StartAny(const DataPiece& value) {
   }
   // Resolve the type url, and report an error if we failed to resolve it.
   StatusOr<const google::protobuf::Type*> resolved_type =
-      parent_->typeinfo_->ResolveTypeUrl(type_url_);
+      parent_->typeinfo()->ResolveTypeUrl(type_url_);
   if (!resolved_type.ok()) {
     parent_->InvalidValue("Any", resolved_type.status().error_message());
     invalid_ = true;
@@ -440,8 +312,8 @@ void ProtoStreamObjectWriter::AnyWriter::StartAny(const DataPiece& value) {
 
   // Create our object writer and initialize it with the first StartObject
   // call.
-  ow_.reset(new ProtoStreamObjectWriter(parent_->typeinfo_, *type, &output_,
-                                        parent_->listener_));
+  ow_.reset(new ProtoStreamObjectWriter(parent_->typeinfo(), *type, &output_,
+                                        parent_->listener()));
   ow_->StartObject("");
 }
 
@@ -453,604 +325,431 @@ void ProtoStreamObjectWriter::AnyWriter::WriteAny() {
   }
   // Render the type_url and value fields directly to the stream.
   // type_url has tag 1 and value has tag 2.
-  WireFormatLite::WriteString(1, type_url_, parent_->stream_.get());
+  WireFormatLite::WriteString(1, type_url_, parent_->stream());
   if (!data_.empty()) {
-    WireFormatLite::WriteBytes(2, data_, parent_->stream_.get());
+    WireFormatLite::WriteBytes(2, data_, parent_->stream());
   }
 }
 
-ProtoStreamObjectWriter::ProtoElement::ProtoElement(
-    const TypeInfo* typeinfo, const google::protobuf::Type& type,
-    ProtoStreamObjectWriter* enclosing)
+ProtoStreamObjectWriter::Item::Item(ProtoStreamObjectWriter* enclosing,
+                                    ItemType item_type, bool is_placeholder,
+                                    bool is_list)
     : BaseElement(NULL),
       ow_(enclosing),
       any_(),
-      field_(NULL),
-      typeinfo_(typeinfo),
-      type_(type),
-      required_fields_(GetRequiredFields(type)),
-      is_repeated_type_(false),
-      size_index_(-1),
-      array_index_(-1),
-      element_type_(GetElementType(type_)) {
-  if (element_type_ == ANY) {
+      item_type_(item_type),
+      is_placeholder_(is_placeholder),
+      is_list_(is_list) {
+  if (item_type_ == ANY) {
     any_.reset(new AnyWriter(ow_));
   }
 }
 
-ProtoStreamObjectWriter::ProtoElement::ProtoElement(
-    ProtoStreamObjectWriter::ProtoElement* parent,
-    const google::protobuf::Field* field, const google::protobuf::Type& type,
-    ElementType element_type)
+ProtoStreamObjectWriter::Item::Item(ProtoStreamObjectWriter::Item* parent,
+                                    ItemType item_type, bool is_placeholder,
+                                    bool is_list)
     : BaseElement(parent),
       ow_(this->parent()->ow_),
       any_(),
-      field_(field),
-      typeinfo_(this->parent()->typeinfo_),
-      type_(type),
-      is_repeated_type_(element_type == ProtoElement::LIST ||
-                        element_type == ProtoElement::STRUCT_LIST ||
-                        element_type == ProtoElement::MAP ||
-                        element_type == ProtoElement::STRUCT_MAP),
-      size_index_(!is_repeated_type_ &&
-                          field->kind() ==
-                              google::protobuf::Field_Kind_TYPE_MESSAGE
-                      ? ow_->size_insert_.size()
-                      : -1),
-      array_index_(is_repeated_type_ ? 0 : -1),
-      element_type_(element_type) {
-  if (!is_repeated_type_) {
-    if (field->cardinality() ==
-        google::protobuf::Field_Cardinality_CARDINALITY_REPEATED) {
-      // Update array_index_ if it is an explicit list.
-      if (this->parent()->array_index_ >= 0) this->parent()->array_index_++;
-    } else {
-      this->parent()->RegisterField(field);
-    }
-    if (field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE) {
-      required_fields_ = GetRequiredFields(type_);
-      int start_pos = ow_->stream_->ByteCount();
-      // length of serialized message is the final buffer position minus
-      // starting buffer position, plus length adjustments for size fields
-      // of any nested messages. We start with -start_pos here, so we only
-      // need to add the final buffer position to it at the end.
-      SizeInfo info = {start_pos, -start_pos};
-      ow_->size_insert_.push_back(info);
-    }
-  }
-  if (element_type == ANY) {
+      item_type_(item_type),
+      is_placeholder_(is_placeholder),
+      is_list_(is_list) {
+  if (item_type == ANY) {
     any_.reset(new AnyWriter(ow_));
   }
 }
 
-ProtoStreamObjectWriter::ProtoElement*
-ProtoStreamObjectWriter::ProtoElement::pop() {
-  // Calls the registered error listener for any required field(s) not yet
-  // seen.
-  for (set<const google::protobuf::Field*>::iterator it =
-           required_fields_.begin();
-       it != required_fields_.end(); ++it) {
-    ow_->MissingField((*it)->name());
-  }
-  // Computes the total number of proto bytes used by a message, also adjusts
-  // the size of all parent messages by the length of this size field.
-  // If size_index_ < 0, this is not a message, so no size field is added.
-  if (size_index_ >= 0) {
-    // Add the final buffer position to compute the total length of this
-    // serialized message. The stored value (before this addition) already
-    // contains the total length of the size fields of all nested messages
-    // minus the initial buffer position.
-    ow_->size_insert_[size_index_].size += ow_->stream_->ByteCount();
-    // Calculate the length required to serialize the size field of the
-    // message, and propagate this additional size information upward to
-    // all enclosing messages.
-    int size = ow_->size_insert_[size_index_].size;
-    int length = CodedOutputStream::VarintSize32(size);
-    for (ProtoElement* e = parent(); e != NULL; e = e->parent()) {
-      // Only nested messages have size field, lists do not have size field.
-      if (e->size_index_ >= 0) {
-        ow_->size_insert_[e->size_index_].size += length;
-      }
-    }
-  }
-  return BaseElement::pop<ProtoElement>();
-}
-
-void ProtoStreamObjectWriter::ProtoElement::RegisterField(
-    const google::protobuf::Field* field) {
-  if (!required_fields_.empty() &&
-      field->cardinality() ==
-          google::protobuf::Field_Cardinality_CARDINALITY_REQUIRED) {
-    required_fields_.erase(field);
-  }
-}
-
-string ProtoStreamObjectWriter::ProtoElement::ToString() const {
-  if (parent() == NULL) return "";
-  string loc = parent()->ToString();
-  if (field_->cardinality() !=
-          google::protobuf::Field_Cardinality_CARDINALITY_REPEATED ||
-      parent()->field_ != field_) {
-    string name = field_->name();
-    int i = 0;
-    while (i < name.size() && (ascii_isalnum(name[i]) || name[i] == '_')) ++i;
-    if (i > 0 && i == name.size()) {  // safe field name
-      if (loc.empty()) {
-        loc = name;
-      } else {
-        StrAppend(&loc, ".", name);
-      }
-    } else {
-      StrAppend(&loc, "[\"", CEscape(name), "\"]");
-    }
-  }
-  if (field_->cardinality() ==
-          google::protobuf::Field_Cardinality_CARDINALITY_REPEATED &&
-      array_index_ > 0) {
-    StrAppend(&loc, "[", array_index_ - 1, "]");
-  }
-  return loc.empty() ? "." : loc;
-}
-
-bool ProtoStreamObjectWriter::ProtoElement::OneofIndexTaken(int32 index) {
-  return ContainsKey(oneof_indices_, index);
-}
-
-void ProtoStreamObjectWriter::ProtoElement::TakeOneofIndex(int32 index) {
-  InsertIfNotPresent(&oneof_indices_, index);
-}
-
-bool ProtoStreamObjectWriter::ProtoElement::InsertMapKeyIfNotPresent(
+bool ProtoStreamObjectWriter::Item::InsertMapKeyIfNotPresent(
     StringPiece map_key) {
   return InsertIfNotPresent(&map_keys_, map_key.ToString());
 }
 
-inline void ProtoStreamObjectWriter::InvalidName(StringPiece unknown_name,
-                                                 StringPiece message) {
-  listener_->InvalidName(location(), ToSnakeCase(unknown_name), message);
-}
-
-inline void ProtoStreamObjectWriter::InvalidValue(StringPiece type_name,
-                                                  StringPiece value) {
-  listener_->InvalidValue(location(), type_name, value);
-}
-
-inline void ProtoStreamObjectWriter::MissingField(StringPiece missing_name) {
-  listener_->MissingField(location(), missing_name);
-}
-
 ProtoStreamObjectWriter* ProtoStreamObjectWriter::StartObject(
     StringPiece name) {
-  // Starting the root message. Create the root ProtoElement and return.
-  if (element_ == NULL) {
-    if (!name.empty()) {
-      InvalidName(name, "Root element should not be named.");
-    }
-    element_.reset(new ProtoElement(typeinfo_, master_type_, this));
+  if (invalid_depth() > 0) {
+    IncrementInvalidDepth();
+    return this;
+  }
+
+  // Starting the root message. Create the root Item and return.
+  // ANY message type does not need special handling, just set the ItemType
+  // to ANY.
+  if (current_ == NULL) {
+    ProtoWriter::StartObject(name);
+    current_.reset(new Item(
+        this, master_type_.name() == kAnyType ? Item::ANY : Item::MESSAGE,
+        false, false));
 
     // If master type is a special type that needs extra values to be written to
     // stream, we write those values.
     if (master_type_.name() == kStructType) {
-      StartStruct(NULL);
-    } else if (master_type_.name() == kStructValueType) {
-      // We got a StartObject call with google.protobuf.Value field. This means
-      // we are starting an object within google.protobuf.Value type. The only
-      // object within that type is a struct type. So start a struct.
-      const google::protobuf::Field* field = StartStructValueInStruct(NULL);
-      StartStruct(field);
+      // Struct has a map<string, Value> field called "fields".
+      // https://github.com/google/protobuf/blob/master/src/google/protobuf/struct.proto
+      // "fields": [
+      Push("fields", Item::MAP, true, true);
+      return this;
     }
-    return this;
-  }
 
-  const google::protobuf::Field* field = NULL;
-  if (element_ != NULL && element_->IsAny()) {
-    element_->any()->StartObject(name);
-    return this;
-  } else if (element_ != NULL &&
-             (element_->IsMap() || element_->IsStructMap())) {
-    if (!ValidMapKey(name)) {
-      ++invalid_depth_;
+    if (master_type_.name() == kStructValueType) {
+      // We got a StartObject call with google.protobuf.Value field. The only
+      // object within that type is a struct type. So start a struct.
+      //
+      // The struct field in Value type is named "struct_value"
+      // https://github.com/google/protobuf/blob/master/src/google/protobuf/struct.proto
+      // Also start the map field "fields" within the struct.
+      // "struct_value": {
+      //   "fields": [
+      Push("struct_value", Item::MESSAGE, true, false);
+      Push("fields", Item::MAP, true, true);
       return this;
     }
 
-    field = StartMapEntry(name);
-    if (element_->IsStructMapEntry()) {
-      // If the top element is a map entry, this means we are starting another
-      // struct within a struct.
-      field = StartStructValueInStruct(field);
+    if (master_type_.name() == kStructListValueType) {
+      InvalidValue(kStructListValueType,
+                   "Cannot start root message with ListValue.");
     }
-  } else if (element_ != NULL && element_->IsStructList()) {
-    // If the top element is a list, then we are starting a list field within a
-    // struct.
-    field = Lookup(name);
-    field = StartStructValueInStruct(field);
-  } else {
-    field = BeginNamed(name, false);
-  }
-  if (field == NULL) {
-    return this;
-  }
 
-  const google::protobuf::Type* type = LookupType(field);
-  if (type == NULL) {
-    ++invalid_depth_;
-    InvalidName(name,
-                StrCat("Missing descriptor for field: ", field->type_url()));
     return this;
   }
 
-  // Check to see if this field is a oneof and that no oneof in that group has
-  // already been set.
-  if (!ValidOneof(*field, name)) {
-    ++invalid_depth_;
+  // Send all ANY events to AnyWriter.
+  if (current_->IsAny()) {
+    current_->any()->StartObject(name);
     return this;
   }
 
-  if (field->type_url() == GetFullTypeWithUrl(kStructType)) {
-    // Start a struct object.
-    StartStruct(field);
-  } else if (field->type_url() == GetFullTypeWithUrl(kStructValueType)) {
-    // We got a StartObject call with google.protobuf.Value field. This means we
-    // are starting an object within google.protobuf.Value type. The only object
-    // within that type is a struct type. So start a struct.
-    field = StartStructValueInStruct(field);
-    StartStruct(field);
-  } else if (field->type_url() == GetFullTypeWithUrl(kAnyType)) {
-    // Begin an Any. We can't do the real work till we get the @type field.
-    WriteTag(*field);
-    element_.reset(
-        new ProtoElement(element_.release(), field, *type, ProtoElement::ANY));
-  } else if (IsMap(*field)) {
-    // Begin a map.
-    // A map is triggered by a StartObject() call if the current field has a map
-    // type. Map values are written to proto in a manner detailed in comments
-    // above StartMapEntry() function.
-    element_.reset(
-        new ProtoElement(element_.release(), field, *type, ProtoElement::MAP));
-  } else {
-      WriteTag(*field);
-    element_.reset(new ProtoElement(element_.release(), field, *type,
-                                    ProtoElement::MESSAGE));
-  }
-  return this;
-}
-
-// Proto3 maps are represented on the wire as a message with
-// "key" and a "value".
-//
-// For example, the syntax:
-// map<key_type, value_type> map_field = N;
-//
-// is represented as:
-// message MapFieldEntry {
-//   option map_entry = true;   // marks the map construct in the descriptor
-//
-//   key_type key = 1;
-//   value_type value = 2;
-// }
-// repeated MapFieldEntry map_field = N;
-//
-// See go/proto3-maps for more information.
-const google::protobuf::Field* ProtoStreamObjectWriter::StartMapEntry(
-    StringPiece name) {
-  // top of stack is already a map field
-  const google::protobuf::Field* field = element_->field();
-  const google::protobuf::Type& type = element_->type();
-  // If we come from a regular map, use MAP_ENTRY or if we come from a struct,
-  // use STRUCT_MAP_ENTRY. These values are used later in StartObject/StartList
-  // or RenderDataPiece for making appropriate decisions.
-  ProtoElement::ElementType element_type = element_->IsStructMap()
-                                               ? ProtoElement::STRUCT_MAP_ENTRY
-                                               : ProtoElement::MAP_ENTRY;
-  WriteTag(*field);
-  element_.reset(
-      new ProtoElement(element_.release(), field, type, element_type));
-  RenderDataPiece("key", DataPiece(name));
-  return BeginNamed("value", false);
-}
+  // If we are within a map, we render name as keys and send StartObject to the
+  // value field.
+  if (current_->IsMap()) {
+    if (!ValidMapKey(name)) {
+      IncrementInvalidDepth();
+      return this;
+    }
 
-// Starts a google.protobuf.Struct.
-// 'field' represents a field in a message of type google.protobuf.Struct.  A
-// struct contains a map with name 'fields'. This function starts this map as
-// well.
-// When 'field' is NULL, it means that the top level message is of struct
-// type.
-void ProtoStreamObjectWriter::StartStruct(
-    const google::protobuf::Field* field) {
-  const google::protobuf::Type* type = NULL;
-  if (field) {
-    type = LookupType(field);
-    WriteTag(*field);
-    element_.reset(new ProtoElement(element_.release(), field, *type,
-                                    ProtoElement::STRUCT));
-  }
-  const google::protobuf::Field* struct_field = BeginNamed("fields", false);
+    // Map is a repeated field of message type with a "key" and a "value" field.
+    // https://developers.google.com/protocol-buffers/docs/proto3?hl=en#maps
+    // message MapFieldEntry {
+    //   key_type key = 1;
+    //   value_type value = 2;
+    // }
+    //
+    // repeated MapFieldEntry map_field = N;
+    //
+    // That means, we render the following element within a list (hence no
+    // name):
+    // { "key": "<name>", "value": {
+    Push("", Item::MESSAGE, false, false);
+    ProtoWriter::RenderDataPiece("key", DataPiece(name));
+    Push("value", Item::MESSAGE, true, false);
+
+    // Make sure we are valid so far after starting map fields.
+    if (invalid_depth() > 0) return this;
+
+    // If top of stack is g.p.Struct type, start the struct the map field within
+    // it.
+    if (element() != NULL && IsStruct(*element()->parent_field())) {
+      // Render "fields": [
+      Push("fields", Item::MAP, true, true);
+      return this;
+    }
 
-  if (!struct_field) {
-    // It is a programmatic error if this happens. Log an error.
-    GOOGLE_LOG(ERROR) << "Invalid internal state. Cannot find 'fields' within "
-               << (field ? field->type_url() : "google.protobuf.Struct");
-    return;
+    // If top of stack is g.p.Value type, start the Struct within it.
+    if (element() != NULL && IsStructValue(*element()->parent_field())) {
+      // Render
+      // "struct_value": {
+      //   "fields": [
+      Push("struct_value", Item::MESSAGE, true, false);
+      Push("fields", Item::MAP, true, true);
+    }
+    return this;
   }
 
-  type = LookupType(struct_field);
-  element_.reset(new ProtoElement(element_.release(), struct_field, *type,
-                                  ProtoElement::STRUCT_MAP));
-}
+  const google::protobuf::Field* field = BeginNamed(name, false);
+  if (field == NULL) return this;
 
-// Starts a "struct_value" within struct.proto's google.protobuf.Value type.
-// 'field' should be of the type google.protobuf.Value.
-// Returns the field identifying "struct_value" within the given field.
-//
-// If field is NULL, then we are starting struct_value at the top-level, in
-// this case skip writing any tag information for the passed field.
-const google::protobuf::Field*
-ProtoStreamObjectWriter::StartStructValueInStruct(
-    const google::protobuf::Field* field) {
-  if (field) {
-    const google::protobuf::Type* type = LookupType(field);
-    WriteTag(*field);
-    element_.reset(new ProtoElement(element_.release(), field, *type,
-                                    ProtoElement::STRUCT_VALUE));
-  }
-  return BeginNamed("struct_value", false);
-}
-
-// Starts a "list_value" within struct.proto's google.protobuf.Value type.
-// 'field' should be of the type google.protobuf.Value.
-// Returns the field identifying "list_value" within the given field.
-//
-// If field is NULL, then we are starting list_value at the top-level, in
-// this case skip writing any tag information for the passed field.
-const google::protobuf::Field* ProtoStreamObjectWriter::StartListValueInStruct(
-    const google::protobuf::Field* field) {
-  if (field) {
-    const google::protobuf::Type* type = LookupType(field);
-    WriteTag(*field);
-    element_.reset(new ProtoElement(element_.release(), field, *type,
-                                    ProtoElement::STRUCT_VALUE));
+  if (IsStruct(*field)) {
+    // Start a struct object.
+    // Render
+    // "<name>": {
+    //   "fields": {
+    Push(name, Item::MESSAGE, false, false);
+    Push("fields", Item::MAP, true, true);
+    return this;
   }
-  const google::protobuf::Field* list_value = BeginNamed("list_value", false);
 
-  if (!list_value) {
-    // It is a programmatic error if this happens. Log an error.
-    GOOGLE_LOG(ERROR) << "Invalid internal state. Cannot find 'list_value' within "
-               << (field ? field->type_url() : "google.protobuf.Value");
-    return field;
+  if (IsStructValue(*field)) {
+    // We got a StartObject call with google.protobuf.Value field.  The only
+    // object within that type is a struct type. So start a struct.
+    // Render
+    // "<name>": {
+    //   "struct_value": {
+    //     "fields": {
+    Push(name, Item::MESSAGE, false, false);
+    Push("struct_value", Item::MESSAGE, true, false);
+    Push("fields", Item::MAP, true, true);
+    return this;
   }
 
-  return StartRepeatedValuesInListValue(list_value);
-}
-
-// Starts the repeated "values" field in struct.proto's
-// google.protobuf.ListValue type. 'field' should be of type
-// google.protobuf.ListValue.
-//
-// If field is NULL, then we are starting ListValue at the top-level, in
-// this case skip writing any tag information for the passed field.
-const google::protobuf::Field*
-ProtoStreamObjectWriter::StartRepeatedValuesInListValue(
-    const google::protobuf::Field* field) {
-  if (field) {
-    const google::protobuf::Type* type = LookupType(field);
-    WriteTag(*field);
-    element_.reset(new ProtoElement(element_.release(), field, *type,
-                                    ProtoElement::STRUCT_LIST_VALUE));
+  if (IsMap(*field)) {
+    // Begin a map. A map is triggered by a StartObject() call if the current
+    // field has a map type.
+    // A map type is always repeated, hence set is_list to true.
+    // Render
+    // "<name>": [
+    Push(name, Item::MAP, false, true);
+    return this;
   }
-  return BeginNamed("values", true);
-}
 
-void ProtoStreamObjectWriter::SkipElements() {
-  if (element_ == NULL) return;
-
-  ProtoElement::ElementType element_type = element_->element_type();
-  while (element_type == ProtoElement::STRUCT ||
-         element_type == ProtoElement::STRUCT_LIST_VALUE ||
-         element_type == ProtoElement::STRUCT_VALUE ||
-         element_type == ProtoElement::STRUCT_MAP_ENTRY ||
-         element_type == ProtoElement::MAP_ENTRY) {
-    element_.reset(element_->pop());
-    element_type =
-        element_ != NULL ? element_->element_type() : ProtoElement::MESSAGE;
-  }
+  // A regular message type. Pass it directly to ProtoWriter.
+  // Render
+  // "<name>": {
+  Push(name, IsAny(*field) ? Item::ANY : Item::MESSAGE, false, false);
+  return this;
 }
 
 ProtoStreamObjectWriter* ProtoStreamObjectWriter::EndObject() {
-  if (invalid_depth_ > 0) {
-    --invalid_depth_;
+  if (invalid_depth() > 0) {
+    DecrementInvalidDepth();
     return this;
   }
-  if (element_ != NULL && element_->IsAny()) {
-    if (element_->any()->EndObject()) {
-      return this;
-    }
-  }
-  if (element_ != NULL) {
-    element_.reset(element_->pop());
-  }
 
-  // Skip sentinel elements added to keep track of new proto3 types - map,
-  // struct.
-  SkipElements();
+  if (current_ == NULL) return this;
 
-
-  // If ending the root element,
-  // then serialize the full message with calculated sizes.
-  if (element_ == NULL) {
-    WriteRootMessage();
+  if (current_->IsAny()) {
+    if (current_->any()->EndObject()) return this;
   }
+
+  Pop();
+
   return this;
 }
 
 ProtoStreamObjectWriter* ProtoStreamObjectWriter::StartList(StringPiece name) {
-  const google::protobuf::Field* field = NULL;
+  if (invalid_depth() > 0) {
+    IncrementInvalidDepth();
+    return this;
+  }
+
   // Since we cannot have a top-level repeated item in protobuf, the only way
-  // element_ can be null when here is when we start a top-level list
-  // google.protobuf.ListValue.
-  if (element_ == NULL) {
+  // this is valid is if we start a special type google.protobuf.ListValue or
+  // google.protobuf.Value.
+  if (current_ == NULL) {
     if (!name.empty()) {
       InvalidName(name, "Root element should not be named.");
+      IncrementInvalidDepth();
+      return this;
     }
-    element_.reset(new ProtoElement(typeinfo_, master_type_, this));
 
     // If master type is a special type that needs extra values to be written to
     // stream, we write those values.
     if (master_type_.name() == kStructValueType) {
       // We got a StartList with google.protobuf.Value master type. This means
       // we have to start the "list_value" within google.protobuf.Value.
-      field = StartListValueInStruct(NULL);
-    } else if (master_type_.name() == kStructListValueType) {
+      //
+      // See
+      // https://github.com/google/protobuf/blob/master/src/google/protobuf/struct.proto
+      //
+      // Render
+      // "<name>": {
+      //   "list_value": {
+      //     "values": [  // Start this list.
+      ProtoWriter::StartObject(name);
+      current_.reset(new Item(this, Item::MESSAGE, false, false));
+      Push("list_value", Item::MESSAGE, true, false);
+      Push("values", Item::MESSAGE, true, true);
+      return this;
+    }
+
+    if (master_type_.name() == kStructListValueType) {
       // We got a StartList with google.protobuf.ListValue master type. This
       // means we have to start the "values" within google.protobuf.ListValue.
-      field = StartRepeatedValuesInListValue(NULL);
+      //
+      // Render
+      // "<name>": {
+      //   "values": [  // Start this list.
+      ProtoWriter::StartObject(name);
+      current_.reset(new Item(this, Item::MESSAGE, false, false));
+      Push("values", Item::MESSAGE, true, true);
+      return this;
     }
 
-    // field is NULL when master_type_ is anything other than
-    // google.protobuf.Value or google.protobuf.ListValue.
-    if (field) {
-      const google::protobuf::Type* type = LookupType(field);
-      element_.reset(new ProtoElement(element_.release(), field, *type,
-                                      ProtoElement::STRUCT_LIST));
-    }
+    // Send the event to ProtoWriter so proper errors can be reported.
+    //
+    // Render a regular list:
+    // "<name>": [
+    ProtoWriter::StartList(name);
+    current_.reset(new Item(this, Item::MESSAGE, false, true));
     return this;
   }
 
-  if (element_->IsAny()) {
-    element_->any()->StartList(name);
+  if (current_->IsAny()) {
+    current_->any()->StartList(name);
     return this;
   }
-  // The type of element we push to stack.
-  ProtoElement::ElementType element_type = ProtoElement::LIST;
 
-  // Check if we need to start a map. This can heppen when there is either a map
-  // or a struct type within a list.
-  if (element_->IsMap() || element_->IsStructMap()) {
+  // If the top of stack is a map, we are starting a list value within a map.
+  // Since map does not allow repeated values, this can only happen when the map
+  // value is of a special type that renders a list in JSON.  These can be one
+  // of 3 cases:
+  // i. We are rendering a list value within google.protobuf.Struct
+  // ii. We are rendering a list value within google.protobuf.Value
+  // iii. We are rendering a list value with type google.protobuf.ListValue.
+  if (current_->IsMap()) {
     if (!ValidMapKey(name)) {
-      ++invalid_depth_;
+      IncrementInvalidDepth();
       return this;
     }
 
-    field = StartMapEntry(name);
-    if (field == NULL) return this;
+    // Start the repeated map entry object.
+    // Render
+    // { "key": "<name>", "value": {
+    Push("", Item::MESSAGE, false, false);
+    ProtoWriter::RenderDataPiece("key", DataPiece(name));
+    Push("value", Item::MESSAGE, true, false);
+
+    // Make sure we are valid after pushing all above items.
+    if (invalid_depth() > 0) return this;
+
+    // case i and ii above. Start "list_value" field within g.p.Value
+    if (element() != NULL && element()->parent_field() != NULL) {
+      // Render
+      // "list_value": {
+      //   "values": [  // Start this list
+      if (IsStructValue(*element()->parent_field())) {
+        Push("list_value", Item::MESSAGE, true, false);
+        Push("values", Item::MESSAGE, true, true);
+        return this;
+      }
 
-    if (element_->IsStructMapEntry()) {
-      // If the top element is a map entry, this means we are starting a list
-      // within a struct or a map.
-      // An example sequence of calls would be
-      //    StartObject -> StartList
-      field = StartListValueInStruct(field);
-      if (field == NULL) return this;
+      // Render
+      // "values": [
+      if (IsStructListValue(*element()->parent_field())) {
+        // case iii above. Bind directly to g.p.ListValue
+        Push("values", Item::MESSAGE, true, true);
+        return this;
+      }
     }
 
-    element_type = ProtoElement::STRUCT_LIST;
-  } else if (element_->IsStructList()) {
-    // If the top element is a STRUCT_LIST, this means we are starting a list
-    // within the current list (inside a struct).
-    // An example call sequence would be
-    //    StartObject -> StartList -> StartList
-    // with StartObject starting a struct.
+    // Report an error.
+    InvalidValue("Map", StrCat("Cannot have repeated items ('", name,
+                               "') within a map."));
+    return this;
+  }
 
-    // Lookup the last list type in element stack as we are adding an element of
-    // the same type.
-    field = Lookup(name);
-    if (field == NULL) return this;
+  // When name is empty and stack is not empty, we are rendering an item within
+  // a list.
+  if (name.empty()) {
+    if (element() != NULL && element()->parent_field() != NULL) {
+      if (IsStructValue(*element()->parent_field())) {
+        // Since it is g.p.Value, we bind directly to the list_value.
+        // Render
+        // {  // g.p.Value item within the list
+        //   "list_value": {
+        //     "values": [
+        Push("", Item::MESSAGE, false, false);
+        Push("list_value", Item::MESSAGE, true, false);
+        Push("values", Item::MESSAGE, true, true);
+        return this;
+      }
 
-    field = StartListValueInStruct(field);
-    if (field == NULL) return this;
+      if (IsStructListValue(*element()->parent_field())) {
+        // Since it is g.p.ListValue, we bind to it directly.
+        // Render
+        // {  // g.p.ListValue item within the list
+        //   "values": [
+        Push("", Item::MESSAGE, false, false);
+        Push("values", Item::MESSAGE, true, true);
+        return this;
+      }
+    }
 
-    element_type = ProtoElement::STRUCT_LIST;
-  } else {
-    // Lookup field corresponding to 'name'. If it is a google.protobuf.Value
-    // or google.protobuf.ListValue type, then StartList is a valid call, start
-    // this list.
-    // We cannot use Lookup() here as it will produce InvalidName() error if the
-    // field is not found. We do not want to error here as it would cause us to
-    // report errors twice, once here and again later in BeginNamed() call.
-    // Also we ignore if the field is not found here as it is caught later.
-    field = typeinfo_->FindField(&element_->type(), name);
-
-    // Only check for oneof collisions on the first StartList call. We identify
-    // the first call with !name.empty() check. Subsequent list element calls
-    // will not have the name filled.
-    if (!name.empty() && field && !ValidOneof(*field, name)) {
-      ++invalid_depth_;
+    // Pass the event to underlying ProtoWriter.
+    Push(name, Item::MESSAGE, false, true);
+    return this;
+  }
+
+  // name is not empty
+  const google::protobuf::Field* field = Lookup(name);
+  if (field == NULL) {
+    IncrementInvalidDepth();
+    return this;
+  }
+
+  if (IsStructValue(*field)) {
+    // If g.p.Value is repeated, start that list. Otherwise, start the
+    // "list_value" within it.
+    if (IsRepeated(*field)) {
+      // Render it just like a regular repeated field.
+      // "<name>": [
+      Push(name, Item::MESSAGE, false, true);
       return this;
     }
 
-    // It is an error to try to bind to map, which behind the scenes is a list.
-    if (field && IsMap(*field)) {
-      // Push field to stack for error location tracking & reporting.
-      element_.reset(new ProtoElement(element_.release(), field,
-                                      *LookupType(field),
-                                      ProtoElement::MESSAGE));
-      InvalidValue("Map", "Cannot bind a list to map.");
-      ++invalid_depth_;
-      element_.reset(element_->pop());
+    // Start the "list_value" field.
+    // Render
+    // "<name>": {
+    //   "list_value": {
+    //     "values": [
+    Push(name, Item::MESSAGE, false, false);
+    Push("list_value", Item::MESSAGE, true, false);
+    Push("values", Item::MESSAGE, true, true);
+    return this;
+  }
+
+  if (IsStructListValue(*field)) {
+    // If g.p.ListValue is repeated, start that list. Otherwise, start the
+    // "values" within it.
+    if (IsRepeated(*field)) {
+      // Render it just like a regular repeated field.
+      // "<name>": [
+      Push(name, Item::MESSAGE, false, true);
       return this;
     }
 
-    if (field && field->type_url() == GetFullTypeWithUrl(kStructValueType)) {
-      // There are 2 cases possible:
-      //   a. g.p.Value is repeated
-      //   b. g.p.Value is not repeated
-      //
-      // For case (a), the StartList should bind to the repeated g.p.Value.
-      // For case (b), the StartList should bind to g.p.ListValue within the
-      // g.p.Value.
-      //
-      // This means, for case (a), we treat it just like any other repeated
-      // message, except we would apply an appropriate element_type so future
-      // Start or Render calls are routed appropriately.
-      if (field->cardinality() !=
-          google::protobuf::Field_Cardinality_CARDINALITY_REPEATED) {
-        field = StartListValueInStruct(field);
-      }
-      element_type = ProtoElement::STRUCT_LIST;
-    } else if (field &&
-               field->type_url() == GetFullTypeWithUrl(kStructListValueType)) {
-      // We got a StartList with google.protobuf.ListValue master type. This
-      // means we have to start the "values" within google.protobuf.ListValue.
-      field = StartRepeatedValuesInListValue(field);
-    } else {
-      // If no special types are to be bound, fall back to normal processing of
-      // StartList.
-      field = BeginNamed(name, true);
-    }
-    if (field == NULL) return this;
+    // Start the "values" field within g.p.ListValue.
+    // Render
+    // "<name>": {
+    //   "values": [
+    Push(name, Item::MESSAGE, false, false);
+    Push("values", Item::MESSAGE, true, true);
+    return this;
   }
 
-  const google::protobuf::Type* type = LookupType(field);
-  if (type == NULL) {
-    ++invalid_depth_;
-    InvalidName(name,
-                StrCat("Missing descriptor for field: ", field->type_url()));
+  // If we are here, the field should be repeated. Report an error otherwise.
+  if (!IsRepeated(*field)) {
+    IncrementInvalidDepth();
+    InvalidName(name, "Proto field is not repeating, cannot start list.");
     return this;
   }
 
-  element_.reset(
-      new ProtoElement(element_.release(), field, *type, element_type));
+  if (IsMap(*field)) {
+    InvalidValue("Map",
+                 StrCat("Cannot bind a list to map for field '", name, "'."));
+    IncrementInvalidDepth();
+    return this;
+  }
+
+  // Pass the event to ProtoWriter.
+  // Render
+  // "<name>": [
+  Push(name, Item::MESSAGE, false, true);
   return this;
 }
 
 ProtoStreamObjectWriter* ProtoStreamObjectWriter::EndList() {
-  if (invalid_depth_ > 0) {
-    --invalid_depth_;
-  } else if (element_ != NULL) {
-    if (element_->IsAny()) {
-      element_->any()->EndList();
-    } else {
-      element_.reset(element_->pop());
-      // Skip sentinel elements added to keep track of new proto3 types - map,
-      // struct.
-      SkipElements();
-    }
+  if (invalid_depth() > 0) {
+    DecrementInvalidDepth();
+    return this;
   }
 
-  // When element_ is NULL, we have reached the root message type. Write out
-  // the bytes.
-  if (element_ == NULL) {
-    WriteRootMessage();
+  if (current_ == NULL) return this;
+
+  if (current_->IsAny()) {
+    current_->any()->EndList();
+    return this;
   }
+
+  Pop();
   return this;
 }
 
@@ -1083,7 +782,7 @@ Status ProtoStreamObjectWriter::RenderStructValue(ProtoStreamObjectWriter* ow,
                     "null values are supported.");
     }
   }
-  ow->RenderDataPiece(struct_field_name, data);
+  ow->ProtoWriter::RenderDataPiece(struct_field_name, data);
   return Status::OK;
 }
 
@@ -1105,15 +804,15 @@ Status ProtoStreamObjectWriter::RenderTimestamp(ProtoStreamObjectWriter* ow,
   }
 
 
-  ow->RenderDataPiece("seconds", DataPiece(seconds));
-  ow->RenderDataPiece("nanos", DataPiece(nanos));
+  ow->ProtoWriter::RenderDataPiece("seconds", DataPiece(seconds));
+  ow->ProtoWriter::RenderDataPiece("nanos", DataPiece(nanos));
   return Status::OK;
 }
 
 static inline util::Status RenderOneFieldPath(ProtoStreamObjectWriter* ow,
                                                 StringPiece path) {
-  ow->RenderDataPiece("paths",
-                      DataPiece(ConvertFieldMaskPath(path, &ToSnakeCase)));
+  ow->ProtoWriter::RenderDataPiece(
+      "paths", DataPiece(ConvertFieldMaskPath(path, &ToSnakeCase)));
   return Status::OK;
 }
 
@@ -1162,224 +861,133 @@ Status ProtoStreamObjectWriter::RenderDuration(ProtoStreamObjectWriter* ow,
                   "Invalid duration format, failed to parse seconds");
   }
 
-  double d_nanos = 0;
-  if (!safe_strtod("0." + s_nanos.ToString(), &d_nanos)) {
-    return Status(INVALID_ARGUMENT,
-                  "Invalid duration format, failed to parse nanos seconds");
+  int32 nanos = 0;
+  Status nanos_status = GetNanosFromStringPiece(
+      s_nanos, "Invalid duration format, failed to parse nano seconds",
+      "Duration value exceeds limits", &nanos);
+  if (!nanos_status.ok()) {
+    return nanos_status;
   }
+  nanos = sign * nanos;
 
-  int32 nanos = sign * static_cast<int32>(d_nanos * kNanosPerSecond);
   int64 seconds = sign * unsigned_seconds;
-
   if (seconds > kMaxSeconds || seconds < kMinSeconds ||
       nanos <= -kNanosPerSecond || nanos >= kNanosPerSecond) {
     return Status(INVALID_ARGUMENT, "Duration value exceeds limits");
   }
 
-  ow->RenderDataPiece("seconds", DataPiece(seconds));
-  ow->RenderDataPiece("nanos", DataPiece(nanos));
+  ow->ProtoWriter::RenderDataPiece("seconds", DataPiece(seconds));
+  ow->ProtoWriter::RenderDataPiece("nanos", DataPiece(nanos));
   return Status::OK;
 }
 
 Status ProtoStreamObjectWriter::RenderWrapperType(ProtoStreamObjectWriter* ow,
                                                   const DataPiece& data) {
-  ow->RenderDataPiece("value", data);
+  ow->ProtoWriter::RenderDataPiece("value", data);
   return Status::OK;
 }
 
 ProtoStreamObjectWriter* ProtoStreamObjectWriter::RenderDataPiece(
     StringPiece name, const DataPiece& data) {
   Status status;
-  if (invalid_depth_ > 0) return this;
-  if (element_ != NULL && element_->IsAny()) {
-    element_->any()->RenderDataPiece(name, data);
+  if (invalid_depth() > 0) return this;
+
+  if (current_ == NULL) {
+    const TypeRenderer* type_renderer =
+        FindTypeRenderer(GetFullTypeWithUrl(master_type_.name()));
+    if (type_renderer == NULL) {
+      InvalidName(name, "Root element must be a message.");
+      return this;
+    }
+    // Render the special type.
+    // "<name>": {
+    //   ... Render special type ...
+    // }
+    ProtoWriter::StartObject(name);
+    status = (*type_renderer)(this, data);
+    if (!status.ok()) {
+      InvalidValue(master_type_.name(),
+                   StrCat("Field '", name, "', ", status.error_message()));
+    }
+    ProtoWriter::EndObject();
+    return this;
+  }
+
+  if (current_->IsAny()) {
+    current_->any()->RenderDataPiece(name, data);
     return this;
   }
 
   const google::protobuf::Field* field = NULL;
-  string type_url;
-  bool is_map_entry = false;
-  // We are at the root when element_ == NULL.
-  if (element_ == NULL) {
-    type_url = GetFullTypeWithUrl(master_type_.name());
-  } else {
-    if (element_->IsMap() || element_->IsStructMap()) {
-      if (!ValidMapKey(name)) return this;
-      is_map_entry = true;
-      field = StartMapEntry(name);
-    } else {
-      field = Lookup(name);
-    }
+  if (current_->IsMap()) {
+    if (!ValidMapKey(name)) return this;
+
+    // Render an item in repeated map list.
+    // { "key": "<name>", "value":
+    Push("", Item::MESSAGE, false, false);
+    ProtoWriter::RenderDataPiece("key", DataPiece(name));
+    field = Lookup("value");
     if (field == NULL) {
+      GOOGLE_LOG(DFATAL) << "Map does not have a value field.";
+      return this;
+    }
+
+    const TypeRenderer* type_renderer = FindTypeRenderer(field->type_url());
+    if (type_renderer != NULL) {
+      // Map's value type is a special type. Render it like a message:
+      // "value": {
+      //   ... Render special type ...
+      // }
+      Push("value", Item::MESSAGE, true, false);
+      status = (*type_renderer)(this, data);
+      if (!status.ok()) {
+        InvalidValue(field->type_url(),
+                     StrCat("Field '", name, "', ", status.error_message()));
+      }
+      Pop();
       return this;
     }
 
-    // Check to see if this field is a oneof and that no oneof in that group has
-    // already been set.
-    if (!ValidOneof(*field, name)) return this;
+    // If we are rendering explicit null values and the backend proto field is
+    // not of the google.protobuf.NullType type, we do nothing.
+    if (data.type() == DataPiece::TYPE_NULL &&
+        field->type_url() != kStructNullValueTypeUrl) {
+      return this;
+    }
 
-    type_url = field->type_url();
+    // Render the map value as a primitive type.
+    ProtoWriter::RenderDataPiece("value", data);
+    Pop();
+    return this;
   }
 
-  // Check if there are any well known type renderers available for type_url.
-  const TypeRenderer* type_renderer = FindTypeRenderer(type_url);
+  field = Lookup(name);
+  if (field == NULL) return this;
+
+  // Check if the field is of special type. Render it accordingly if so.
+  const TypeRenderer* type_renderer = FindTypeRenderer(field->type_url());
   if (type_renderer != NULL) {
-    // Push the current element to stack so lookups in type_renderer will
-    // find the fields. We do an EndObject soon after, which pops this. This is
-    // safe because all well-known types are messages.
-    if (element_ == NULL) {
-      element_.reset(new ProtoElement(typeinfo_, master_type_, this));
-    } else {
-      if (field) {
-        WriteTag(*field);
-        const google::protobuf::Type* type = LookupType(field);
-        element_.reset(new ProtoElement(element_.release(), field, *type,
-                                        ProtoElement::MESSAGE));
-      }
-    }
+    Push(name, Item::MESSAGE, false, false);
     status = (*type_renderer)(this, data);
     if (!status.ok()) {
-      InvalidValue(type_url,
+      InvalidValue(field->type_url(),
                    StrCat("Field '", name, "', ", status.error_message()));
     }
-    EndObject();
-    return this;
-  } else if (element_ == NULL) {  // no message type found at root
-    element_.reset(new ProtoElement(typeinfo_, master_type_, this));
-    InvalidName(name, "Root element must be a message.");
+    Pop();
     return this;
   }
 
-  if (field == NULL) {
-    return this;
-  }
-  const google::protobuf::Type* type = LookupType(field);
-  if (type == NULL) {
-    InvalidName(name,
-                StrCat("Missing descriptor for field: ", field->type_url()));
+  // If we are rendering explicit null values and the backend proto field is
+  // not of the google.protobuf.NullType type, we do nothing.
+  if (data.type() == DataPiece::TYPE_NULL &&
+      field->type_url() != kStructNullValueTypeUrl) {
     return this;
   }
 
-  // Whether we should pop at the end. Set to true if the data field is a
-  // message type, which can happen in case of struct values.
-  bool should_pop = false;
-
-  RenderSimpleDataPiece(*field, *type, data);
-
-  if (should_pop && element_ != NULL) {
-    element_.reset(element_->pop());
-  }
-
-  if (is_map_entry) {
-    // Ending map is the same as ending an object.
-    EndObject();
-  }
+  ProtoWriter::RenderDataPiece(name, data);
   return this;
 }
 
-void ProtoStreamObjectWriter::RenderSimpleDataPiece(
-    const google::protobuf::Field& field, const google::protobuf::Type& type,
-    const DataPiece& data) {
-  // If we are rendering explicit null values and the backend proto field is not
-  // of the google.protobuf.NullType type, we do nothing.
-  if (data.type() == DataPiece::TYPE_NULL &&
-      field.type_url() != kStructNullValueTypeUrl) {
-    return;
-  }
-
-  // Pushing a ProtoElement and then pop it off at the end for 2 purposes:
-  // error location reporting and required field accounting.
-  element_.reset(new ProtoElement(element_.release(), &field, type,
-                                  ProtoElement::MESSAGE));
-
-  // Make sure that field represents a simple data type.
-  if (field.kind() == google::protobuf::Field_Kind_TYPE_UNKNOWN ||
-      field.kind() == google::protobuf::Field_Kind_TYPE_MESSAGE) {
-    InvalidValue(field.type_url().empty()
-                     ? google::protobuf::Field_Kind_Name(field.kind())
-                     : field.type_url(),
-                 data.ValueAsStringOrDefault(""));
-    return;
-  }
-
-  Status status;
-  switch (field.kind()) {
-    case google::protobuf::Field_Kind_TYPE_INT32: {
-      status = WriteInt32(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_SFIXED32: {
-      status = WriteSFixed32(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_SINT32: {
-      status = WriteSInt32(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_FIXED32: {
-      status = WriteFixed32(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_UINT32: {
-      status = WriteUInt32(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_INT64: {
-      status = WriteInt64(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_SFIXED64: {
-      status = WriteSFixed64(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_SINT64: {
-      status = WriteSInt64(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_FIXED64: {
-      status = WriteFixed64(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_UINT64: {
-      status = WriteUInt64(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_DOUBLE: {
-      status = WriteDouble(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_FLOAT: {
-      status = WriteFloat(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_BOOL: {
-      status = WriteBool(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_BYTES: {
-      status = WriteBytes(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_STRING: {
-      status = WriteString(field.number(), data, stream_.get());
-      break;
-    }
-    case google::protobuf::Field_Kind_TYPE_ENUM: {
-      status = WriteEnum(field.number(), data,
-                         typeinfo_->GetEnumByTypeUrl(field.type_url()),
-                         stream_.get());
-      break;
-    }
-    default:  // TYPE_GROUP or TYPE_MESSAGE
-      status = Status(INVALID_ARGUMENT, data.ToString().ValueOrDie());
-  }
-  if (!status.ok()) {
-    InvalidValue(google::protobuf::Field_Kind_Name(field.kind()),
-                 status.error_message());
-  }
-  element_.reset(element_->pop());
-}
-
 // Map of functions that are responsible for rendering well known type
 // represented by the key.
 hash_map<string, ProtoStreamObjectWriter::TypeRenderer>*
@@ -1446,45 +1054,12 @@ ProtoStreamObjectWriter::FindTypeRenderer(const string& type_url) {
   return FindOrNull(*renderers_, type_url);
 }
 
-ProtoStreamObjectWriter::ProtoElement::ElementType
-ProtoStreamObjectWriter::GetElementType(const google::protobuf::Type& type) {
-  if (type.name() == kAnyType) {
-    return ProtoElement::ANY;
-  } else if (type.name() == kStructType) {
-    return ProtoElement::STRUCT;
-  } else if (type.name() == kStructValueType) {
-    return ProtoElement::STRUCT_VALUE;
-  } else if (type.name() == kStructListValueType) {
-    return ProtoElement::STRUCT_LIST_VALUE;
-  } else {
-    return ProtoElement::MESSAGE;
-  }
-}
-
-bool ProtoStreamObjectWriter::ValidOneof(const google::protobuf::Field& field,
-                                         StringPiece unnormalized_name) {
-  if (element_ == NULL) return true;
-
-  if (field.oneof_index() > 0) {
-    if (element_->OneofIndexTaken(field.oneof_index())) {
-      InvalidValue(
-          "oneof",
-          StrCat("oneof field '",
-                 element_->type().oneofs(field.oneof_index() - 1),
-                 "' is already set. Cannot set '", unnormalized_name, "'"));
-      return false;
-    }
-    element_->TakeOneofIndex(field.oneof_index());
-  }
-  return true;
-}
-
 bool ProtoStreamObjectWriter::ValidMapKey(StringPiece unnormalized_name) {
-  if (element_ == NULL) return true;
+  if (current_ == NULL) return true;
 
-  if (!element_->InsertMapKeyIfNotPresent(unnormalized_name)) {
-    InvalidName(
-        unnormalized_name,
+  if (!current_->InsertMapKeyIfNotPresent(unnormalized_name)) {
+    listener()->InvalidName(
+        location(), unnormalized_name,
         StrCat("Repeated map key: '", unnormalized_name, "' is already set."));
     return false;
   }
@@ -1492,134 +1067,30 @@ bool ProtoStreamObjectWriter::ValidMapKey(StringPiece unnormalized_name) {
   return true;
 }
 
-const google::protobuf::Field* ProtoStreamObjectWriter::BeginNamed(
-    StringPiece name, bool is_list) {
-  if (invalid_depth_ > 0) {
-    ++invalid_depth_;
-    return NULL;
-  }
-  const google::protobuf::Field* field = Lookup(name);
-  if (field == NULL) {
-    ++invalid_depth_;
-    // InvalidName() already called in Lookup().
-    return NULL;
-  }
-  if (is_list &&
-      field->cardinality() !=
-          google::protobuf::Field_Cardinality_CARDINALITY_REPEATED) {
-    ++invalid_depth_;
-    InvalidName(name, "Proto field is not repeating, cannot start list.");
-    return NULL;
-  }
-  return field;
-}
+void ProtoStreamObjectWriter::Push(StringPiece name, Item::ItemType item_type,
+                                   bool is_placeholder, bool is_list) {
+  is_list ? ProtoWriter::StartList(name) : ProtoWriter::StartObject(name);
 
-const google::protobuf::Field* ProtoStreamObjectWriter::Lookup(
-    StringPiece unnormalized_name) {
-  ProtoElement* e = element();
-  if (e == NULL) {
-    InvalidName(unnormalized_name, "Root element must be a message.");
-    return NULL;
-  }
-  if (unnormalized_name.empty()) {
-    // Objects in repeated field inherit the same field descriptor.
-    if (e->field() == NULL) {
-      InvalidName(unnormalized_name, "Proto fields must have a name.");
-    } else if (e->field()->cardinality() !=
-               google::protobuf::Field_Cardinality_CARDINALITY_REPEATED) {
-      InvalidName(unnormalized_name, "Proto fields must have a name.");
-      return NULL;
-    }
-    return e->field();
-  }
-  const google::protobuf::Field* field =
-      typeinfo_->FindField(&e->type(), unnormalized_name);
-  if (field == NULL) InvalidName(unnormalized_name, "Cannot find field.");
-  return field;
-}
-
-const google::protobuf::Type* ProtoStreamObjectWriter::LookupType(
-    const google::protobuf::Field* field) {
-  return (field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE
-              ? typeinfo_->GetTypeByTypeUrl(field->type_url())
-              : &element_->type());
+  // invalid_depth == 0 means it is a successful StartObject or StartList.
+  if (invalid_depth() == 0)
+    current_.reset(
+        new Item(current_.release(), item_type, is_placeholder, is_list));
 }
 
-// Looks up the oneof struct field based on the data type.
-StatusOr<const google::protobuf::Field*>
-ProtoStreamObjectWriter::LookupStructField(DataPiece::Type type) {
-  const google::protobuf::Field* field = NULL;
-  switch (type) {
-    // Our JSON parser parses numbers as either int64, uint64, or double.
-    case DataPiece::TYPE_INT64:
-    case DataPiece::TYPE_UINT64:
-    case DataPiece::TYPE_DOUBLE: {
-      field = Lookup("number_value");
-      break;
-    }
-    case DataPiece::TYPE_STRING: {
-      field = Lookup("string_value");
-      break;
-    }
-    case DataPiece::TYPE_BOOL: {
-      field = Lookup("bool_value");
-      break;
-    }
-    case DataPiece::TYPE_NULL: {
-      field = Lookup("null_value");
-      break;
-    }
-    default: { return Status(INVALID_ARGUMENT, "Invalid struct data type"); }
+void ProtoStreamObjectWriter::Pop() {
+  // Pop all placeholder items sending StartObject or StartList events to
+  // ProtoWriter according to is_list value.
+  while (current_ != NULL && current_->is_placeholder()) {
+    PopOneElement();
   }
-  if (field == NULL) {
-    return Status(INVALID_ARGUMENT, "Could not lookup struct field");
+  if (current_ != NULL) {
+    PopOneElement();
   }
-  return field;
 }
 
-void ProtoStreamObjectWriter::WriteRootMessage() {
-  GOOGLE_DCHECK(!done_);
-  int curr_pos = 0;
-  // Calls the destructor of CodedOutputStream to remove any uninitialized
-  // memory from the Cord before we read it.
-  stream_.reset(NULL);
-  const void* data;
-  int length;
-  google::protobuf::io::ArrayInputStream input_stream(buffer_.data(), buffer_.size());
-  while (input_stream.Next(&data, &length)) {
-    if (length == 0) continue;
-    int num_bytes = length;
-    // Write up to where we need to insert the size field.
-    // The number of bytes we may write is the smaller of:
-    //   - the current fragment size
-    //   - the distance to the next position where a size field needs to be
-    //     inserted.
-    if (!size_insert_.empty() &&
-        size_insert_.front().pos - curr_pos < num_bytes) {
-      num_bytes = size_insert_.front().pos - curr_pos;
-    }
-    output_->Append(static_cast<const char*>(data), num_bytes);
-    if (num_bytes < length) {
-      input_stream.BackUp(length - num_bytes);
-    }
-    curr_pos += num_bytes;
-    // Insert the size field.
-    //   size_insert_.front():      the next <index, size> pair to be written.
-    //   size_insert_.front().pos:  position of the size field.
-    //   size_insert_.front().size: the size (integer) to be inserted.
-    if (!size_insert_.empty() && curr_pos == size_insert_.front().pos) {
-      // Varint32 occupies at most 10 bytes.
-      uint8 insert_buffer[10];
-      uint8* insert_buffer_pos = CodedOutputStream::WriteVarint32ToArray(
-          size_insert_.front().size, insert_buffer);
-      output_->Append(reinterpret_cast<const char*>(insert_buffer),
-                      insert_buffer_pos - insert_buffer);
-      size_insert_.pop_front();
-    }
-  }
-  output_->Flush();
-  stream_.reset(new CodedOutputStream(&adapter_));
-  done_ = true;
+void ProtoStreamObjectWriter::PopOneElement() {
+  current_->is_list() ? ProtoWriter::EndList() : ProtoWriter::EndObject();
+  current_.reset(current_->pop<Item>());
 }
 
 bool ProtoStreamObjectWriter::IsMap(const google::protobuf::Field& field) {
@@ -1630,7 +1101,7 @@ bool ProtoStreamObjectWriter::IsMap(const google::protobuf::Field& field) {
     return false;
   }
   const google::protobuf::Type* field_type =
-      typeinfo_->GetTypeByTypeUrl(field.type_url());
+      typeinfo()->GetTypeByTypeUrl(field.type_url());
 
   // TODO(xiaofeng): Unify option names.
   return GetBoolOptionOrDefault(field_type->options(),
@@ -1638,12 +1109,23 @@ bool ProtoStreamObjectWriter::IsMap(const google::protobuf::Field& field) {
          GetBoolOptionOrDefault(field_type->options(), "map_entry", false);
 }
 
-void ProtoStreamObjectWriter::WriteTag(const google::protobuf::Field& field) {
-  WireFormatLite::WireType wire_type = WireFormatLite::WireTypeForFieldType(
-      static_cast<WireFormatLite::FieldType>(field.kind()));
-  stream_->WriteTag(WireFormatLite::MakeTag(field.number(), wire_type));
+bool ProtoStreamObjectWriter::IsAny(const google::protobuf::Field& field) {
+  return GetTypeWithoutUrl(field.type_url()) == kAnyType;
 }
 
+bool ProtoStreamObjectWriter::IsStruct(const google::protobuf::Field& field) {
+  return GetTypeWithoutUrl(field.type_url()) == kStructType;
+}
+
+bool ProtoStreamObjectWriter::IsStructValue(
+    const google::protobuf::Field& field) {
+  return GetTypeWithoutUrl(field.type_url()) == kStructValueType;
+}
+
+bool ProtoStreamObjectWriter::IsStructListValue(
+    const google::protobuf::Field& field) {
+  return GetTypeWithoutUrl(field.type_url()) == kStructListValueType;
+}
 
 }  // namespace converter
 }  // namespace util
diff --git a/src/google/protobuf/util/internal/protostream_objectwriter.h b/src/google/protobuf/util/internal/protostream_objectwriter.h
index 6e133679..08ac6e33 100644
--- a/src/google/protobuf/util/internal/protostream_objectwriter.h
+++ b/src/google/protobuf/util/internal/protostream_objectwriter.h
@@ -42,6 +42,7 @@
 #include <google/protobuf/util/internal/type_info.h>
 #include <google/protobuf/util/internal/datapiece.h>
 #include <google/protobuf/util/internal/error_listener.h>
+#include <google/protobuf/util/internal/proto_writer.h>
 #include <google/protobuf/util/internal/structured_objectwriter.h>
 #include <google/protobuf/util/type_resolver.h>
 #include <google/protobuf/stubs/bytestream.h>
@@ -67,9 +68,11 @@ namespace converter {
 class ObjectLocationTracker;
 
 // An ObjectWriter that can write protobuf bytes directly from writer events.
+// This class supports all special types like Struct and Map. It uses
+// the ProtoWriter class to write raw proto bytes.
 //
 // It also supports streaming.
-class LIBPROTOBUF_EXPORT ProtoStreamObjectWriter : public StructuredObjectWriter {
+class LIBPROTOBUF_EXPORT ProtoStreamObjectWriter : public ProtoWriter {
  public:
 // Constructor. Does not take ownership of any parameter passed in.
   ProtoStreamObjectWriter(TypeResolver* type_resolver,
@@ -82,56 +85,13 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectWriter : public StructuredObjectWriter
   virtual ProtoStreamObjectWriter* EndObject();
   virtual ProtoStreamObjectWriter* StartList(StringPiece name);
   virtual ProtoStreamObjectWriter* EndList();
-  virtual ProtoStreamObjectWriter* RenderBool(StringPiece name, bool value) {
-    return RenderDataPiece(name, DataPiece(value));
-  }
-  virtual ProtoStreamObjectWriter* RenderInt32(StringPiece name, int32 value) {
-    return RenderDataPiece(name, DataPiece(value));
-  }
-  virtual ProtoStreamObjectWriter* RenderUint32(StringPiece name,
-                                                uint32 value) {
-    return RenderDataPiece(name, DataPiece(value));
-  }
-  virtual ProtoStreamObjectWriter* RenderInt64(StringPiece name, int64 value) {
-    return RenderDataPiece(name, DataPiece(value));
-  }
-  virtual ProtoStreamObjectWriter* RenderUint64(StringPiece name,
-                                                uint64 value) {
-    return RenderDataPiece(name, DataPiece(value));
-  }
-  virtual ProtoStreamObjectWriter* RenderDouble(StringPiece name,
-                                                double value) {
-    return RenderDataPiece(name, DataPiece(value));
-  }
-  virtual ProtoStreamObjectWriter* RenderFloat(StringPiece name, float value) {
-    return RenderDataPiece(name, DataPiece(value));
-  }
-  virtual ProtoStreamObjectWriter* RenderString(StringPiece name,
-                                                StringPiece value) {
-    return RenderDataPiece(name, DataPiece(value));
-  }
-  virtual ProtoStreamObjectWriter* RenderBytes(StringPiece name,
-                                               StringPiece value) {
-    return RenderDataPiece(name, DataPiece(value, false));
-  }
-  virtual ProtoStreamObjectWriter* RenderNull(StringPiece name) {
-    return RenderDataPiece(name, DataPiece::NullData());
-  }
 
   // Renders a DataPiece 'value' into a field whose wire type is determined
   // from the given field 'name'.
-  ProtoStreamObjectWriter* RenderDataPiece(StringPiece name,
-                                           const DataPiece& value);
+  virtual ProtoStreamObjectWriter* RenderDataPiece(StringPiece name,
+                                                   const DataPiece& value);
 
-  // Returns the location tracker to use for tracking locations for errors.
-  const LocationTrackerInterface& location() {
-    return element_ != NULL ? *element_ : *tracker_;
-  }
-
-  // When true, we finished writing to output a complete message.
-  bool done() const { return done_; }
-
- private:
+ protected:
   // Function that renders a well known type with modified behavior.
   typedef util::Status (*TypeRenderer)(ProtoStreamObjectWriter*,
                                          const DataPiece&);
@@ -192,73 +152,37 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectWriter : public StructuredObjectWriter
     bool has_injected_value_message_;
   };
 
-  class LIBPROTOBUF_EXPORT ProtoElement : public BaseElement, public LocationTrackerInterface {
+  // Represents an item in a stack of items used to keep state between
+  // ObjectWrier events.
+  class LIBPROTOBUF_EXPORT Item : public BaseElement {
    public:
-    // Indicates the type of element. Special types like LIST, MAP, MAP_ENTRY,
-    // STRUCT etc. are used to deduce other information based on their position
-    // on the stack of elements.
-    enum ElementType {
-      MESSAGE,       // Simple message
-      LIST,          // List/repeated element
-      MAP,           // Proto3 map type
-      MAP_ENTRY,     // Proto3 map message type, with 'key' and 'value' fields
-      ANY,           // Proto3 Any type
-      STRUCT,        // Proto3 struct type
-      STRUCT_VALUE,  // Struct's Value message type
-      STRUCT_LIST,   // List type indicator within a struct
-      STRUCT_LIST_VALUE,  // Struct Value's ListValue message type
-      STRUCT_MAP,         // Struct within a struct type
-      STRUCT_MAP_ENTRY    // Struct map's entry type with 'key' and 'value'
-                          // fields
+    // Indicates the type of item.
+    enum ItemType {
+      MESSAGE,  // Simple message
+      MAP,      // Proto3 map type
+      ANY,      // Proto3 Any type
     };
 
-    // Constructor for the root element. No parent nor field.
-    ProtoElement(const TypeInfo* typeinfo, const google::protobuf::Type& type,
-                 ProtoStreamObjectWriter* enclosing);
-
-    // Constructor for a field of an element.
-    ProtoElement(ProtoElement* parent, const google::protobuf::Field* field,
-                 const google::protobuf::Type& type, ElementType element_type);
+    // Constructor for the root item.
+    Item(ProtoStreamObjectWriter* enclosing, ItemType item_type,
+         bool is_placeholder, bool is_list);
 
-    virtual ~ProtoElement() {}
+    // Constructor for a field of a message.
+    Item(Item* parent, ItemType item_type, bool is_placeholder, bool is_list);
 
-    // Called just before the destructor for clean up:
-    //   - reports any missing required fields
-    //   - computes the space needed by the size field, and augment the
-    //     length of all parent messages by this additional space.
-    //   - releases and returns the parent pointer.
-    ProtoElement* pop();
-
-    // Accessors
-    const google::protobuf::Field* field() const { return field_; }
-    const google::protobuf::Type& type() const { return type_; }
+    virtual ~Item() {}
 
     // These functions return true if the element type is corresponding to the
     // type in function name.
-    bool IsMap() { return element_type_ == MAP; }
-    bool IsStructMap() { return element_type_ == STRUCT_MAP; }
-    bool IsStructMapEntry() { return element_type_ == STRUCT_MAP_ENTRY; }
-    bool IsStructList() { return element_type_ == STRUCT_LIST; }
-    bool IsAny() { return element_type_ == ANY; }
-
-    ElementType element_type() { return element_type_; }
-
-    void RegisterField(const google::protobuf::Field* field);
-    virtual string ToString() const;
+    bool IsMap() { return item_type_ == MAP; }
+    bool IsAny() { return item_type_ == ANY; }
 
     AnyWriter* any() const { return any_.get(); }
 
-    virtual ProtoElement* parent() const {
-      return static_cast<ProtoElement*>(BaseElement::parent());
+    virtual Item* parent() const {
+      return static_cast<Item*>(BaseElement::parent());
     }
 
-    // Returns true if the index is already taken by a preceeding oneof input.
-    bool OneofIndexTaken(int32 index);
-
-    // Marks the oneof 'index' as taken. Future inputs to this oneof will
-    // generate an error.
-    void TakeOneofIndex(int32 index);
-
     // Inserts map key into hash set if and only if the key did NOT already
     // exist in hash set.
     // The hash set (map_keys_) is ONLY used to keep track of map keys.
@@ -266,6 +190,9 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectWriter : public StructuredObjectWriter
     // already present.
     bool InsertMapKeyIfNotPresent(StringPiece map_key);
 
+    bool is_placeholder() const { return is_placeholder_; }
+    bool is_list() const { return is_list_; }
+
    private:
     // Used for access to variables of the enclosing instance of
     // ProtoStreamObjectWriter.
@@ -274,126 +201,42 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectWriter : public StructuredObjectWriter
     // A writer for Any objects, handles all Any-related nonsense.
     google::protobuf::scoped_ptr<AnyWriter> any_;
 
-    // Describes the element as a field in the parent message.
-    // field_ is NULL if and only if this element is the root element.
-    const google::protobuf::Field* field_;
-
-    // TypeInfo to lookup types.
-    const TypeInfo* typeinfo_;
-
-    // Additional variables if this element is a message:
-    // (Root element is always a message).
-    // descriptor_     : describes allowed fields in the message.
-    // required_fields_: set of required fields.
-    // is_repeated_type_ : true if the element is of type list or map.
-    // size_index_     : index into ProtoStreamObjectWriter::size_insert_
-    //                   for later insertion of serialized message length.
-    const google::protobuf::Type& type_;
-    std::set<const google::protobuf::Field*> required_fields_;
-    const bool is_repeated_type_;
-    const int size_index_;
-
-    // Tracks position in repeated fields, needed for LocationTrackerInterface.
-    int array_index_;
-
     // The type of this element, see enum for permissible types.
-    ElementType element_type_;
-
-    // Set of oneof indices already seen for the type_. Used to validate
-    // incoming messages so no more than one oneof is set.
-    hash_set<int32> oneof_indices_;
+    ItemType item_type_;
 
     // Set of map keys already seen for the type_. Used to validate incoming
     // messages so no map key appears more than once.
     hash_set<string> map_keys_;
 
-    GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS(ProtoElement);
-  };
+    // Conveys whether this Item is a placeholder or not. Placeholder items are
+    // pushed to stack to account for special types.
+    bool is_placeholder_;
 
-  // Container for inserting 'size' information at the 'pos' position.
-  struct SizeInfo {
-    const int pos;
-    int size;
+    // Conveys whether this Item is a list or not. This is used to send
+    // StartList or EndList calls to underlying ObjectWriter.
+    bool is_list_;
+
+    GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS(Item);
   };
 
   ProtoStreamObjectWriter(const TypeInfo* typeinfo,
                           const google::protobuf::Type& type,
                           strings::ByteSink* output, ErrorListener* listener);
 
-  ProtoElement* element() { return element_.get(); }
-
-  // Helper methods for calling ErrorListener. See error_listener.h.
-  void InvalidName(StringPiece unknown_name, StringPiece message);
-  void InvalidValue(StringPiece type_name, StringPiece value);
-  void MissingField(StringPiece missing_name);
-
-  // Common code for BeginObject() and BeginList() that does invalid_depth_
-  // bookkeeping associated with name lookup.
-  const google::protobuf::Field* BeginNamed(StringPiece name, bool is_list);
-
-  // Lookup the field in the current element. Looks in the base descriptor
-  // and in any extension. This will report an error if the field cannot be
-  // found or if multiple matching extensions are found.
-  const google::protobuf::Field* Lookup(StringPiece name);
-
-  // Lookup the field type in the type descriptor. Returns NULL if the type
-  // is not known.
-  const google::protobuf::Type* LookupType(
-      const google::protobuf::Field* field);
-
-  // Looks up the oneof struct Value field depending on the type.
-  // On failure to find, it returns an appropriate error.
-  util::StatusOr<const google::protobuf::Field*> LookupStructField(
-      DataPiece::Type type);
-
-  // Starts an entry in map. This will be called after placing map element at
-  // the top of the stack. Uses this information to write map entries.
-  const google::protobuf::Field* StartMapEntry(StringPiece name);
-
-  // Starts a google.protobuf.Struct.
-  // 'field' is of type google.protobuf.Struct.
-  // If field is NULL, it indicates that the top-level message is a struct
-  // type.
-  void StartStruct(const google::protobuf::Field* field);
-
-  // Starts another struct within a struct.
-  // 'field' is of type google.protobuf.Value (see struct.proto).
-  const google::protobuf::Field* StartStructValueInStruct(
-      const google::protobuf::Field* field);
-
-  // Starts a list within a struct.
-  // 'field' is of type google.protobuf.ListValue (see struct.proto).
-  const google::protobuf::Field* StartListValueInStruct(
-      const google::protobuf::Field* field);
-
-  // Starts the repeated "values" field in struct.proto's
-  // google.protobuf.ListValue type. 'field' should be of type
-  // google.protobuf.ListValue.
-  const google::protobuf::Field* StartRepeatedValuesInListValue(
-      const google::protobuf::Field* field);
-
-  // Pops sentinel elements off the stack.
-  void SkipElements();
-
-  // Write serialized output to the final output ByteSink, inserting all
-  // the size information for nested messages that are missing from the
-  // intermediate Cord buffer.
-  void WriteRootMessage();
-
   // Returns true if the field is a map.
   bool IsMap(const google::protobuf::Field& field);
 
   // Returns true if the field is an any.
   bool IsAny(const google::protobuf::Field& field);
 
-  // Helper method to write proto tags based on the given field.
-  void WriteTag(const google::protobuf::Field& field);
+  // Returns true if the field is google.protobuf.Struct.
+  bool IsStruct(const google::protobuf::Field& field);
 
+  // Returns true if the field is google.protobuf.Value.
+  bool IsStructValue(const google::protobuf::Field& field);
 
-  // Helper function to render primitive data types in DataPiece.
-  void RenderSimpleDataPiece(const google::protobuf::Field& field,
-                             const google::protobuf::Type& type,
-                             const DataPiece& data);
+  // Returns true if the field is google.protobuf.ListValue.
+  bool IsStructListValue(const google::protobuf::Field& field);
 
   // Renders google.protobuf.Value in struct.proto. It picks the right oneof
   // type based on value's type.
@@ -417,69 +260,46 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectWriter : public StructuredObjectWriter
   static util::Status RenderWrapperType(ProtoStreamObjectWriter* ow,
                                           const DataPiece& value);
 
-  // Helper functions to create the map and find functions responsible for
-  // rendering well known types, keyed by type URL.
-  static hash_map<string, TypeRenderer>* renderers_;
   static void InitRendererMap();
   static void DeleteRendererMap();
   static TypeRenderer* FindTypeRenderer(const string& type_url);
 
-  // Returns the ProtoElement::ElementType for the given Type.
-  static ProtoElement::ElementType GetElementType(
-      const google::protobuf::Type& type);
-
-  // Returns true if the field for type_ can be set as a oneof. If field is not
-  // a oneof type, this function does nothing and returns true.
-  // If another field for this oneof is already set, this function returns
-  // false. It also calls the appropriate error callback.
-  // unnormalized_name is used for error string.
-  bool ValidOneof(const google::protobuf::Field& field,
-                  StringPiece unnormalized_name);
-
   // Returns true if the map key for type_ is not duplicated key.
   // If map key is duplicated key, this function returns false.
-  // Note that caller should make sure that the current proto element (element_)
+  // Note that caller should make sure that the current proto element (current_)
   // is of element type MAP or STRUCT_MAP.
   // It also calls the appropriate error callback and unnormalzied_name is used
   // for error string.
   bool ValidMapKey(StringPiece unnormalized_name);
 
+  // Pushes an item on to the stack. Also calls either StartObject or StartList
+  // on the underlying ObjectWriter depending on whether is_list is false or
+  // not.
+  // is_placeholder conveys whether the item is a placeholder item or not.
+  // Placeholder items are pushed when adding auxillary types' StartObject or
+  // StartList calls.
+  void Push(StringPiece name, Item::ItemType item_type, bool is_placeholder,
+            bool is_list);
+
+  // Pops items from the stack. All placeholder items are popped until a
+  // non-placeholder item is found.
+  void Pop();
+
+  // Pops one element from the stack. Calls EndObject() or EndList() on the
+  // underlying ObjectWriter depending on the value of is_list_.
+  void PopOneElement();
+
+ private:
+  // Helper functions to create the map and find functions responsible for
+  // rendering well known types, keyed by type URL.
+  static hash_map<string, TypeRenderer>* renderers_;
+
   // Variables for describing the structure of the input tree:
   // master_type_: descriptor for the whole protobuf message.
-  // typeinfo_ : the TypeInfo object to lookup types.
   const google::protobuf::Type& master_type_;
-  const TypeInfo* typeinfo_;
-  // Whether we own the typeinfo_ object.
-  bool own_typeinfo_;
-
-  // Indicates whether we finished writing root message completely.
-  bool done_;
-
-  // Variable for internal state processing:
-  // element_    : the current element.
-  // size_insert_: sizes of nested messages.
-  //               pos  - position to insert the size field.
-  //               size - size value to be inserted.
-  google::protobuf::scoped_ptr<ProtoElement> element_;
-  std::deque<SizeInfo> size_insert_;
-
-  // Variables for output generation:
-  // output_  : pointer to an external ByteSink for final user-visible output.
-  // buffer_  : buffer holding partial message before being ready for output_.
-  // adapter_ : internal adapter between CodedOutputStream and Cord buffer_.
-  // stream_  : wrapper for writing tags and other encodings in wire format.
-  strings::ByteSink* output_;
-  string buffer_;
-  google::protobuf::io::StringOutputStream adapter_;
-  google::protobuf::scoped_ptr<google::protobuf::io::CodedOutputStream> stream_;
-
-  // Variables for error tracking and reporting:
-  // listener_     : a place to report any errors found.
-  // invalid_depth_: number of enclosing invalid nested messages.
-  // tracker_      : the root location tracker interface.
-  ErrorListener* listener_;
-  int invalid_depth_;
-  google::protobuf::scoped_ptr<LocationTrackerInterface> tracker_;
+
+  // The current element, variable for internal state processing.
+  google::protobuf::scoped_ptr<Item> current_;
 
   GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS(ProtoStreamObjectWriter);
 };
diff --git a/src/google/protobuf/util/internal/protostream_objectwriter_test.cc b/src/google/protobuf/util/internal/protostream_objectwriter_test.cc
index cb9f97f7..c7667c21 100644
--- a/src/google/protobuf/util/internal/protostream_objectwriter_test.cc
+++ b/src/google/protobuf/util/internal/protostream_objectwriter_test.cc
@@ -241,6 +241,21 @@ TEST_P(ProtoStreamObjectWriterTest, SimpleMessage) {
   CheckOutput(book);
 }
 
+TEST_P(ProtoStreamObjectWriterTest, CustomJsonName) {
+  Book book;
+  Author* robert = book.mutable_author();
+  robert->set_id(12345);
+  robert->set_name("robert");
+
+  ow_->StartObject("")
+      ->StartObject("author")
+      ->RenderUint64("@id", 12345)
+      ->RenderString("name", "robert")
+      ->EndObject()
+      ->EndObject();
+  CheckOutput(book);
+}
+
 TEST_P(ProtoStreamObjectWriterTest, PrimitiveFromStringConversion) {
   Primitive full;
   full.set_fix32(101);
@@ -796,10 +811,6 @@ TEST_P(ProtoStreamObjectWriterTest, RootNamedList) {
               InvalidName(_, StringPiece("oops"),
                           StringPiece("Root element should not be named.")))
       .With(Args<0>(HasObjectLocation("")));
-  EXPECT_CALL(listener_,
-              InvalidName(_, StringPiece(""),
-                          StringPiece("Proto fields must have a name.")))
-      .With(Args<0>(HasObjectLocation("")));
   ow_->StartList("oops")->RenderString("", "item")->EndList();
   CheckOutput(empty, 0);
 }
@@ -864,6 +875,18 @@ INSTANTIATE_TEST_CASE_P(DifferentTypeInfoSourceTest,
                         ::testing::Values(
                             testing::USE_TYPE_RESOLVER));
 
+TEST_P(ProtoStreamObjectWriterTimestampDurationTest, ParseTimestamp) {
+  TimestampDuration timestamp;
+  google::protobuf::Timestamp* ts = timestamp.mutable_ts();
+  ts->set_seconds(1448249855);
+  ts->set_nanos(33155000);
+
+  ow_->StartObject("")
+      ->RenderString("ts", "2015-11-23T03:37:35.033155Z")
+      ->EndObject();
+  CheckOutput(timestamp);
+}
+
 TEST_P(ProtoStreamObjectWriterTimestampDurationTest, InvalidTimestampError1) {
   TimestampDuration timestamp;
 
@@ -922,9 +945,66 @@ TEST_P(ProtoStreamObjectWriterTimestampDurationTest, InvalidTimestampError4) {
   CheckOutput(timestamp);
 }
 
-// TODO(skarvaje): Write a test for nanos that exceed limit. Currently, it is
-// not possible to construct a test case where nanos exceed limit because of
-// floating point arithmetic.
+TEST_P(ProtoStreamObjectWriterTimestampDurationTest, InvalidTimestampError5) {
+  TimestampDuration timestamp;
+
+  EXPECT_CALL(
+      listener_,
+      InvalidValue(_,
+                   StringPiece("type.googleapis.com/google.protobuf.Timestamp"),
+                   StringPiece("Field 'ts', Invalid time format: "
+                               "2015-11-23T03:37:35.033155   Z")));
+
+  ow_->StartObject("")
+      // Whitespace in the Timestamp nanos is not allowed.
+      ->RenderString("ts", "2015-11-23T03:37:35.033155   Z")
+      ->EndObject();
+  CheckOutput(timestamp);
+}
+
+TEST_P(ProtoStreamObjectWriterTimestampDurationTest, InvalidTimestampError6) {
+  TimestampDuration timestamp;
+
+  EXPECT_CALL(
+      listener_,
+      InvalidValue(_,
+                   StringPiece("type.googleapis.com/google.protobuf.Timestamp"),
+                   StringPiece("Field 'ts', Invalid time format: "
+                               "2015-11-23T03:37:35.033155 1234Z")));
+
+  ow_->StartObject("")
+      // Whitespace in the Timestamp nanos is not allowed.
+      ->RenderString("ts", "2015-11-23T03:37:35.033155 1234Z")
+      ->EndObject();
+  CheckOutput(timestamp);
+}
+
+TEST_P(ProtoStreamObjectWriterTimestampDurationTest, InvalidTimestampError7) {
+  TimestampDuration timestamp;
+
+  EXPECT_CALL(
+      listener_,
+      InvalidValue(_,
+                   StringPiece("type.googleapis.com/google.protobuf.Timestamp"),
+                   StringPiece("Field 'ts', Invalid time format: "
+                               "2015-11-23T03:37:35.033abc155Z")));
+
+  ow_->StartObject("")
+      // Non-numeric characters in the Timestamp nanos is not allowed.
+      ->RenderString("ts", "2015-11-23T03:37:35.033abc155Z")
+      ->EndObject();
+  CheckOutput(timestamp);
+}
+
+TEST_P(ProtoStreamObjectWriterTimestampDurationTest, ParseDuration) {
+  TimestampDuration duration;
+  google::protobuf::Duration* dur = duration.mutable_dur();
+  dur->set_seconds(1448216930);
+  dur->set_nanos(132262000);
+
+  ow_->StartObject("")->RenderString("dur", "1448216930.132262s")->EndObject();
+  CheckOutput(duration);
+}
 
 TEST_P(ProtoStreamObjectWriterTimestampDurationTest, InvalidDurationError1) {
   TimestampDuration duration;
@@ -962,7 +1042,7 @@ TEST_P(ProtoStreamObjectWriterTimestampDurationTest, InvalidDurationError3) {
       InvalidValue(
           _, StringPiece("type.googleapis.com/google.protobuf.Duration"),
           StringPiece("Field 'dur', Invalid duration format, failed to "
-                      "parse nanos seconds")));
+                      "parse nano seconds")));
 
   ow_->StartObject("")->RenderString("dur", "123.DEFs")->EndObject();
   CheckOutput(duration);
@@ -981,6 +1061,19 @@ TEST_P(ProtoStreamObjectWriterTimestampDurationTest, InvalidDurationError4) {
   CheckOutput(duration);
 }
 
+TEST_P(ProtoStreamObjectWriterTimestampDurationTest, InvalidDurationError5) {
+  TimestampDuration duration;
+
+  EXPECT_CALL(
+      listener_,
+      InvalidValue(_,
+                   StringPiece("type.googleapis.com/google.protobuf.Duration"),
+                   StringPiece("Field 'dur', Duration value exceeds limits")));
+
+  ow_->StartObject("")->RenderString("dur", "0.1000000001s")->EndObject();
+  CheckOutput(duration);
+}
+
 TEST_P(ProtoStreamObjectWriterTimestampDurationTest,
        MismatchedTimestampTypeInput) {
   TimestampDuration timestamp;
@@ -1066,12 +1159,12 @@ TEST_P(ProtoStreamObjectWriterStructTest, StructInvalidInputFailure) {
 TEST_P(ProtoStreamObjectWriterStructTest, SimpleRepeatedStructMapKeyTest) {
   EXPECT_CALL(
       listener_,
-      InvalidName(_, StringPiece("k1"),
-                  StringPiece("Repeated map key: 'k1' is already set.")));
+      InvalidName(_, StringPiece("gBike"),
+                  StringPiece("Repeated map key: 'gBike' is already set.")));
   ow_->StartObject("")
       ->StartObject("object")
-      ->RenderString("k1", "v1")
-      ->RenderString("k1", "v2")
+      ->RenderString("gBike", "v1")
+      ->RenderString("gBike", "v2")
       ->EndObject()
       ->EndObject();
 }
@@ -1121,10 +1214,11 @@ INSTANTIATE_TEST_CASE_P(DifferentTypeInfoSourceTest,
 
 TEST_P(ProtoStreamObjectWriterMapTest, MapShouldNotAcceptList) {
   MapIn mm;
-  EXPECT_CALL(listener_,
-              InvalidValue(_, StringPiece("Map"),
-                           StringPiece("Cannot bind a list to map.")))
-      .With(Args<0>(HasObjectLocation("map_input")));
+  EXPECT_CALL(
+      listener_,
+      InvalidValue(
+          _, StringPiece("Map"),
+          StringPiece("Cannot bind a list to map for field 'map_input'.")));
   ow_->StartObject("")
       ->StartList("map_input")
       ->RenderString("a", "b")
diff --git a/src/google/protobuf/util/internal/testdata/books.proto b/src/google/protobuf/util/internal/testdata/books.proto
index 6e2f109b..82b81760 100644
--- a/src/google/protobuf/util/internal/testdata/books.proto
+++ b/src/google/protobuf/util/internal/testdata/books.proto
@@ -66,7 +66,7 @@ message Publisher {
 
 // An author of a book
 message Author {
-  optional uint64 id = 1;
+  optional uint64 id = 1 [json_name = "@id"];
   optional string name = 2;
   repeated string pseudonym = 3;
   optional bool alive = 4;
diff --git a/src/google/protobuf/util/internal/testdata/default_value.proto b/src/google/protobuf/util/internal/testdata/default_value.proto
index ebbdf6ab..cccc741c 100644
--- a/src/google/protobuf/util/internal/testdata/default_value.proto
+++ b/src/google/protobuf/util/internal/testdata/default_value.proto
@@ -75,9 +75,10 @@ message DefaultValueTestCases {
   IntToStringMap int_to_string = 403;
   MixedMap mixed1 = 404;
   MixedMap2 mixed2 = 405;
-  MessageMap map_of_objects = 406;
-  MixedMap mixed_empty = 407;
-  MessageMap message_map_empty = 408;
+  MixedMap2 empty_mixed2 = 406;
+  MessageMap map_of_objects = 407;
+  MixedMap mixed_empty = 408;
+  MessageMap message_map_empty = 409;
   DoubleValueMessage double_value = 501;
   DoubleValueMessage double_value_default = 502;
 }
diff --git a/src/google/protobuf/util/internal/testdata/default_value_test.proto b/src/google/protobuf/util/internal/testdata/default_value_test.proto
index 21b85e6d..93288341 100644
--- a/src/google/protobuf/util/internal/testdata/default_value_test.proto
+++ b/src/google/protobuf/util/internal/testdata/default_value_test.proto
@@ -43,4 +43,11 @@ message DefaultValueTest {
   bool bool_value = 13;
   string string_value = 15;
   bytes bytes_value = 17 [ctype = CORD];
+
+  enum EnumDefault {
+    ENUM_FIRST = 0;
+    ENUM_SECOND = 1;
+    ENUM_THIRD = 2;
+  }
+  EnumDefault enum_value = 18;
 }
diff --git a/src/google/protobuf/util/internal/type_info.cc b/src/google/protobuf/util/internal/type_info.cc
index a45a76e3..00a8ee7a 100644
--- a/src/google/protobuf/util/internal/type_info.cc
+++ b/src/google/protobuf/util/internal/type_info.cc
@@ -136,8 +136,7 @@ class TypeInfoForTypeResolver : public TypeInfo {
     for (int i = 0; i < type->fields_size(); ++i) {
       const google::protobuf::Field& field = type->fields(i);
       StringPiece name = field.name();
-      StringPiece camel_case_name =
-          *string_storage_.insert(ToCamelCase(name)).first;
+      StringPiece camel_case_name = field.json_name();
       const StringPiece* existing = InsertOrReturnExisting(
           &camel_case_name_table_, camel_case_name, name);
       if (existing && *existing != name) {
diff --git a/src/google/protobuf/util/internal/utility.cc b/src/google/protobuf/util/internal/utility.cc
index 61899c24..1ddf2487 100644
--- a/src/google/protobuf/util/internal/utility.cc
+++ b/src/google/protobuf/util/internal/utility.cc
@@ -49,7 +49,8 @@ namespace converter {
 namespace {
 const StringPiece SkipWhiteSpace(StringPiece str) {
   StringPiece::size_type i;
-  for (i = 0; i < str.size() && isspace(str[i]); ++i) {}
+  for (i = 0; i < str.size() && isspace(str[i]); ++i) {
+  }
   GOOGLE_DCHECK(i == str.size() || !isspace(str[i]));
   return StringPiece(str, i);
 }
@@ -160,6 +161,19 @@ const google::protobuf::Field* FindFieldInTypeOrNull(
   return NULL;
 }
 
+const google::protobuf::Field* FindJsonFieldInTypeOrNull(
+    const google::protobuf::Type* type, StringPiece json_name) {
+  if (type != NULL) {
+    for (int i = 0; i < type->fields_size(); ++i) {
+      const google::protobuf::Field& field = type->fields(i);
+      if (field.json_name() == json_name) {
+        return &field;
+      }
+    }
+  }
+  return NULL;
+}
+
 const google::protobuf::EnumValue* FindEnumValueByNameOrNull(
     const google::protobuf::Enum* enum_type, StringPiece enum_name) {
   if (enum_type != NULL) {
@@ -316,16 +330,23 @@ string FloatAsString(float value) {
   return DoubleAsString(value);
 }
 
-bool SafeStrToFloat(StringPiece str, float *value) {
+bool SafeStrToFloat(StringPiece str, float* value) {
   double double_value;
   if (!safe_strtod(str, &double_value)) {
     return false;
   }
-  *value = static_cast<float>(double_value);
 
-  if (MathLimits<float>::IsInf(*value)) {
+  if (MathLimits<double>::IsInf(double_value) ||
+      MathLimits<double>::IsNaN(double_value))
+    return false;
+
+  // Fail if the value is not representable in float.
+  if (double_value > std::numeric_limits<float>::max() ||
+      double_value < -std::numeric_limits<float>::max()) {
     return false;
   }
+
+  *value = static_cast<float>(double_value);
   return true;
 }
 
diff --git a/src/google/protobuf/util/internal/utility.h b/src/google/protobuf/util/internal/utility.h
index 5ba97bd2..33df8eda 100644
--- a/src/google/protobuf/util/internal/utility.h
+++ b/src/google/protobuf/util/internal/utility.h
@@ -127,6 +127,11 @@ const google::protobuf::Option* FindOptionOrNull(
 const google::protobuf::Field* FindFieldInTypeOrNull(
     const google::protobuf::Type* type, StringPiece field_name);
 
+// Similar to FindFieldInTypeOrNull, but this looks up fields with given
+// json_name.
+const google::protobuf::Field* FindJsonFieldInTypeOrNull(
+    const google::protobuf::Type* type, StringPiece json_name);
+
 // Finds and returns the EnumValue identified by enum_name in the passed tech
 // Enum object. Returns NULL if none found.
 const google::protobuf::EnumValue* FindEnumValueByNameOrNull(
diff --git a/src/google/protobuf/util/json_format_proto3.proto b/src/google/protobuf/util/json_format_proto3.proto
index e8137677..a1e24c18 100644
--- a/src/google/protobuf/util/json_format_proto3.proto
+++ b/src/google/protobuf/util/json_format_proto3.proto
@@ -165,3 +165,12 @@ message TestListValue {
   google.protobuf.ListValue value = 1;
   repeated google.protobuf.ListValue repeated_value = 2;
 }
+
+message TestBoolValue {
+  bool bool_value = 1;
+  map<bool, int32> bool_map = 2;
+}
+
+message TestCustomJsonName {
+  int32 value = 1 [json_name = "@value"];
+}
diff --git a/src/google/protobuf/util/message_differencer.cc b/src/google/protobuf/util/message_differencer.cc
index 47237e5a..0f879dc7 100644
--- a/src/google/protobuf/util/message_differencer.cc
+++ b/src/google/protobuf/util/message_differencer.cc
@@ -238,9 +238,25 @@ void MessageDifferencer::TreatAsSet(const FieldDescriptor* field) {
   GOOGLE_CHECK(key_comparator == NULL)
       << "Cannot treat this repeated field as both Map and Set for"
       << " comparison.  Field name is: " << field->full_name();
+  GOOGLE_CHECK(list_fields_.find(field) == list_fields_.end())
+      << "Cannot treat the same field as both SET and LIST. Field name is: "
+      << field->full_name();
   set_fields_.insert(field);
 }
 
+void MessageDifferencer::TreatAsList(const FieldDescriptor* field) {
+  GOOGLE_CHECK(field->is_repeated()) << "Field must be repeated: "
+                              << field->full_name();
+  const MapKeyComparator* key_comparator = GetMapKeyComparator(field);
+  GOOGLE_CHECK(key_comparator == NULL)
+      << "Cannot treat this repeated field as both Map and Set for"
+      << " comparison.  Field name is: " << field->full_name();
+  GOOGLE_CHECK(set_fields_.find(field) == set_fields_.end())
+      << "Cannot treat the same field as both SET and LIST. Field name is: "
+      << field->full_name();
+  list_fields_.insert(field);
+}
+
 void MessageDifferencer::TreatAsMap(const FieldDescriptor* field,
                                     const FieldDescriptor* key) {
   GOOGLE_CHECK(field->is_repeated()) << "Field must be repeated: "
@@ -255,6 +271,9 @@ void MessageDifferencer::TreatAsMap(const FieldDescriptor* field,
   GOOGLE_CHECK(set_fields_.find(field) == set_fields_.end())
       << "Cannot treat this repeated field as both Map and Set for "
       << "comparison.";
+  GOOGLE_CHECK(list_fields_.find(field) == list_fields_.end())
+      << "Cannot treat this repeated field as both Map and List for "
+      << "comparison.";
   MapKeyComparator* key_comparator =
       new MultipleFieldsMapKeyComparator(this, key);
   owned_key_comparators_.push_back(key_comparator);
@@ -920,7 +939,8 @@ bool MessageDifferencer::CheckPathChanged(
 bool MessageDifferencer::IsTreatedAsSet(const FieldDescriptor* field) {
   if (!field->is_repeated()) return false;
   if (field->is_map()) return true;
-  if (repeated_field_comparison_ == AS_SET) return true;
+  if (repeated_field_comparison_ == AS_SET)
+    return list_fields_.find(field) == list_fields_.end();
   return (set_fields_.find(field) != set_fields_.end());
 }
 
diff --git a/src/google/protobuf/util/message_differencer.h b/src/google/protobuf/util/message_differencer.h
index 34c173db..3ea74e67 100644
--- a/src/google/protobuf/util/message_differencer.h
+++ b/src/google/protobuf/util/message_differencer.h
@@ -397,9 +397,16 @@ class LIBPROTOBUF_EXPORT MessageDifferencer {
   // + n^3) in which n^3 is the time complexity of the maximum matching
   // algorithm.
   //
-  // REQUIRES:  field->is_repeated()
+  // REQUIRES:  field->is_repeated() and field not registered with TreatAsList
   void TreatAsSet(const FieldDescriptor* field);
 
+  // The elements of the given repeated field will be treated as a list for
+  // diffing purposes, so different orderings of the same elements will NOT be
+  // considered equal.
+  //
+  // REQUIRED: field->is_repeated() and field not registered with TreatAsSet
+  void TreatAsList(const FieldDescriptor* field);
+
   // The elements of the given repeated field will be treated as a map for
   // diffing purposes, with |key| being the map key.  Thus, elements with the
   // same key will be compared even if they do not appear at the same index.
@@ -791,6 +798,7 @@ class LIBPROTOBUF_EXPORT MessageDifferencer {
   RepeatedFieldComparison repeated_field_comparison_;
 
   FieldSet set_fields_;
+  FieldSet list_fields_;
   // Keeps track of MapKeyComparators that are created within
   // MessageDifferencer. These MapKeyComparators should be deleted
   // before MessageDifferencer is destroyed.
diff --git a/src/google/protobuf/util/message_differencer_unittest.cc b/src/google/protobuf/util/message_differencer_unittest.cc
index 701b94ae..4e9ca348 100755
--- a/src/google/protobuf/util/message_differencer_unittest.cc
+++ b/src/google/protobuf/util/message_differencer_unittest.cc
@@ -1103,12 +1103,19 @@ TEST(MessageDifferencerTest, RepeatedFieldSetTest_Combination) {
   msg1.add_rw("change"); msg2.add_rw("change");
 
   // Compare
-  util::MessageDifferencer differencer;
-  differencer.TreatAsMap(msg1.GetDescriptor()->FindFieldByName("item"),
-                         item->GetDescriptor()->FindFieldByName("a"));
-  differencer.TreatAsSet(msg1.GetDescriptor()->FindFieldByName("rv"));
-  differencer.TreatAsSet(item->GetDescriptor()->FindFieldByName("ra"));
-  EXPECT_TRUE(differencer.Compare(msg1, msg2));
+  util::MessageDifferencer differencer1;
+  differencer1.TreatAsMap(msg1.GetDescriptor()->FindFieldByName("item"),
+                          item->GetDescriptor()->FindFieldByName("a"));
+  differencer1.TreatAsSet(msg1.GetDescriptor()->FindFieldByName("rv"));
+  differencer1.TreatAsSet(item->GetDescriptor()->FindFieldByName("ra"));
+  EXPECT_TRUE(differencer1.Compare(msg1, msg2));
+
+  util::MessageDifferencer differencer2;
+  differencer2.TreatAsMap(msg1.GetDescriptor()->FindFieldByName("item"),
+                          item->GetDescriptor()->FindFieldByName("a"));
+  differencer2.set_repeated_field_comparison(util::MessageDifferencer::AS_SET);
+  differencer2.TreatAsList(msg1.GetDescriptor()->FindFieldByName("rw"));
+  EXPECT_TRUE(differencer2.Compare(msg1, msg2));
 }
 
 TEST(MessageDifferencerTest, RepeatedFieldMapTest_Partial) {
@@ -1168,6 +1175,11 @@ TEST(MessageDifferencerTest, RepeatedFieldSetTest_Duplicates) {
   differencer.TreatAsSet(GetFieldDescriptor(a, "rv"));
   EXPECT_TRUE(differencer.Compare(b, a));
   EXPECT_FALSE(differencer.Compare(c, a));
+
+  util::MessageDifferencer differencer1;
+  differencer1.set_repeated_field_comparison(util::MessageDifferencer::AS_SET);
+  EXPECT_TRUE(differencer1.Compare(b, a));
+  EXPECT_FALSE(differencer1.Compare(c, a));
 }
 
 TEST(MessageDifferencerTest, RepeatedFieldSetTest_PartialSimple) {
diff --git a/src/google/protobuf/util/type_resolver_util.cc b/src/google/protobuf/util/type_resolver_util.cc
index a0996954..96393903 100644
--- a/src/google/protobuf/util/type_resolver_util.cc
+++ b/src/google/protobuf/util/type_resolver_util.cc
@@ -159,7 +159,10 @@ class DescriptorPoolTypeResolver : public TypeResolver {
     }
     field->set_number(descriptor->number());
     field->set_name(descriptor->name());
-    field->set_json_name(converter::ToCamelCase(descriptor->name()));
+    field->set_json_name(descriptor->json_name());
+    if (descriptor->has_default_value()) {
+      field->set_default_value(DefaultValueAsString(descriptor));
+    }
     if (descriptor->type() == FieldDescriptor::TYPE_MESSAGE) {
       field->set_type_url(GetTypeUrl(descriptor->message_type()));
     } else if (descriptor->type() == FieldDescriptor::TYPE_ENUM) {
@@ -200,6 +203,46 @@ class DescriptorPoolTypeResolver : public TypeResolver {
     return url_prefix_ + "/" + descriptor->full_name();
   }
 
+  string DefaultValueAsString(const FieldDescriptor* descriptor) {
+    switch (descriptor->cpp_type()) {
+      case FieldDescriptor::CPPTYPE_INT32:
+        return SimpleItoa(descriptor->default_value_int32());
+        break;
+      case FieldDescriptor::CPPTYPE_INT64:
+        return SimpleItoa(descriptor->default_value_int64());
+        break;
+      case FieldDescriptor::CPPTYPE_UINT32:
+        return SimpleItoa(descriptor->default_value_uint32());
+        break;
+      case FieldDescriptor::CPPTYPE_UINT64:
+        return SimpleItoa(descriptor->default_value_uint64());
+        break;
+      case FieldDescriptor::CPPTYPE_FLOAT:
+        return SimpleFtoa(descriptor->default_value_float());
+        break;
+      case FieldDescriptor::CPPTYPE_DOUBLE:
+        return SimpleDtoa(descriptor->default_value_double());
+        break;
+      case FieldDescriptor::CPPTYPE_BOOL:
+        return descriptor->default_value_bool() ? "true" : "false";
+        break;
+      case FieldDescriptor::CPPTYPE_STRING:
+        if (descriptor->type() == FieldDescriptor::TYPE_BYTES) {
+          return CEscape(descriptor->default_value_string());
+        } else {
+          return descriptor->default_value_string();
+        }
+        break;
+      case FieldDescriptor::CPPTYPE_ENUM:
+        return descriptor->default_value_enum()->name();
+        break;
+      case FieldDescriptor::CPPTYPE_MESSAGE:
+        GOOGLE_LOG(DFATAL) << "Messages can't have default values!";
+        break;
+    }
+    return "";
+  }
+
   string url_prefix_;
   const DescriptorPool* pool_;
 };
diff --git a/src/google/protobuf/util/type_resolver_util_test.cc b/src/google/protobuf/util/type_resolver_util_test.cc
index 74b2d0da..8a0bf652 100644
--- a/src/google/protobuf/util/type_resolver_util_test.cc
+++ b/src/google/protobuf/util/type_resolver_util_test.cc
@@ -43,6 +43,7 @@
 #include <google/protobuf/map_unittest.pb.h>
 #include <google/protobuf/test_util.h>
 #include <google/protobuf/unittest.pb.h>
+#include <google/protobuf/util/json_format_proto3.pb.h>
 #include <google/protobuf/util/type_resolver.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
@@ -332,6 +333,19 @@ TEST_F(DescriptorPoolTypeResolverTest, TestEnum) {
   EnumHasValue(type, "NEG", -1);
 }
 
+TEST_F(DescriptorPoolTypeResolverTest, TestJsonName) {
+  Type type;
+  ASSERT_TRUE(resolver_->ResolveMessageType(
+                           GetTypeUrl<protobuf_unittest::TestAllTypes>(), &type)
+                  .ok());
+  EXPECT_EQ("optionalInt32", FindField(type, "optional_int32")->json_name());
+
+  ASSERT_TRUE(resolver_->ResolveMessageType(
+                           GetTypeUrl<proto3::TestCustomJsonName>(), &type)
+                  .ok());
+  EXPECT_EQ("@value", FindField(type, "value")->json_name());
+}
+
 }  // namespace
 }  // namespace util
 }  // namespace protobuf
diff --git a/src/google/protobuf/wrappers.pb.cc b/src/google/protobuf/wrappers.pb.cc
index e153687b..212dd219 100644
--- a/src/google/protobuf/wrappers.pb.cc
+++ b/src/google/protobuf/wrappers.pb.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/wire_format_lite_inl.h>
@@ -262,10 +263,10 @@ void protobuf_AddDesc_google_2fprotobuf_2fwrappers_2eproto() {
     "e\030\001 \001(\004\"\033\n\nInt32Value\022\r\n\005value\030\001 \001(\005\"\034\n\013"
     "UInt32Value\022\r\n\005value\030\001 \001(\r\"\032\n\tBoolValue\022"
     "\r\n\005value\030\001 \001(\010\"\034\n\013StringValue\022\r\n\005value\030\001"
-    " \001(\t\"\033\n\nBytesValue\022\r\n\005value\030\001 \001(\014BP\n\023com"
-    ".google.protobufB\rWrappersProtoP\001\240\001\001\242\002\003G"
-    "PB\252\002\036Google.Protobuf.WellKnownTypesb\006pro"
-    "to3", 403);
+    " \001(\t\"\033\n\nBytesValue\022\r\n\005value\030\001 \001(\014BS\n\023com"
+    ".google.protobufB\rWrappersProtoP\001\240\001\001\370\001\001\242"
+    "\002\003GPB\252\002\036Google.Protobuf.WellKnownTypesb\006"
+    "proto3", 406);
   ::google::protobuf::MessageFactory::InternalRegisterGeneratedFile(
     "google/protobuf/wrappers.proto", &protobuf_RegisterTypes);
   DoubleValue::default_instance_ = new DoubleValue();
@@ -318,6 +319,14 @@ DoubleValue::DoubleValue()
   // @@protoc_insertion_point(constructor:google.protobuf.DoubleValue)
 }
 
+DoubleValue::DoubleValue(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.DoubleValue)
+}
+
 void DoubleValue::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -342,10 +351,20 @@ DoubleValue::~DoubleValue() {
 }
 
 void DoubleValue::SharedDtor() {
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
   if (this != default_instance_) {
   }
 }
 
+void DoubleValue::ArenaDtor(void* object) {
+  DoubleValue* _this = reinterpret_cast< DoubleValue* >(object);
+  (void)_this;
+}
+void DoubleValue::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void DoubleValue::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -364,11 +383,7 @@ const DoubleValue& DoubleValue::default_instance() {
 DoubleValue* DoubleValue::default_instance_ = NULL;
 
 DoubleValue* DoubleValue::New(::google::protobuf::Arena* arena) const {
-  DoubleValue* n = new DoubleValue;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<DoubleValue>(arena);
 }
 
 void DoubleValue::Clear() {
@@ -495,6 +510,18 @@ bool DoubleValue::IsInitialized() const {
 
 void DoubleValue::Swap(DoubleValue* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    DoubleValue temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void DoubleValue::UnsafeArenaSwap(DoubleValue* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void DoubleValue::InternalSwap(DoubleValue* other) {
@@ -542,6 +569,14 @@ FloatValue::FloatValue()
   // @@protoc_insertion_point(constructor:google.protobuf.FloatValue)
 }
 
+FloatValue::FloatValue(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.FloatValue)
+}
+
 void FloatValue::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -566,10 +601,20 @@ FloatValue::~FloatValue() {
 }
 
 void FloatValue::SharedDtor() {
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
   if (this != default_instance_) {
   }
 }
 
+void FloatValue::ArenaDtor(void* object) {
+  FloatValue* _this = reinterpret_cast< FloatValue* >(object);
+  (void)_this;
+}
+void FloatValue::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void FloatValue::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -588,11 +633,7 @@ const FloatValue& FloatValue::default_instance() {
 FloatValue* FloatValue::default_instance_ = NULL;
 
 FloatValue* FloatValue::New(::google::protobuf::Arena* arena) const {
-  FloatValue* n = new FloatValue;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<FloatValue>(arena);
 }
 
 void FloatValue::Clear() {
@@ -719,6 +760,18 @@ bool FloatValue::IsInitialized() const {
 
 void FloatValue::Swap(FloatValue* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    FloatValue temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void FloatValue::UnsafeArenaSwap(FloatValue* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void FloatValue::InternalSwap(FloatValue* other) {
@@ -766,6 +819,14 @@ Int64Value::Int64Value()
   // @@protoc_insertion_point(constructor:google.protobuf.Int64Value)
 }
 
+Int64Value::Int64Value(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.Int64Value)
+}
+
 void Int64Value::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -790,10 +851,20 @@ Int64Value::~Int64Value() {
 }
 
 void Int64Value::SharedDtor() {
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
   if (this != default_instance_) {
   }
 }
 
+void Int64Value::ArenaDtor(void* object) {
+  Int64Value* _this = reinterpret_cast< Int64Value* >(object);
+  (void)_this;
+}
+void Int64Value::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void Int64Value::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -812,11 +883,7 @@ const Int64Value& Int64Value::default_instance() {
 Int64Value* Int64Value::default_instance_ = NULL;
 
 Int64Value* Int64Value::New(::google::protobuf::Arena* arena) const {
-  Int64Value* n = new Int64Value;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<Int64Value>(arena);
 }
 
 void Int64Value::Clear() {
@@ -945,6 +1012,18 @@ bool Int64Value::IsInitialized() const {
 
 void Int64Value::Swap(Int64Value* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    Int64Value temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void Int64Value::UnsafeArenaSwap(Int64Value* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void Int64Value::InternalSwap(Int64Value* other) {
@@ -992,6 +1071,14 @@ UInt64Value::UInt64Value()
   // @@protoc_insertion_point(constructor:google.protobuf.UInt64Value)
 }
 
+UInt64Value::UInt64Value(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.UInt64Value)
+}
+
 void UInt64Value::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -1016,10 +1103,20 @@ UInt64Value::~UInt64Value() {
 }
 
 void UInt64Value::SharedDtor() {
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
   if (this != default_instance_) {
   }
 }
 
+void UInt64Value::ArenaDtor(void* object) {
+  UInt64Value* _this = reinterpret_cast< UInt64Value* >(object);
+  (void)_this;
+}
+void UInt64Value::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void UInt64Value::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -1038,11 +1135,7 @@ const UInt64Value& UInt64Value::default_instance() {
 UInt64Value* UInt64Value::default_instance_ = NULL;
 
 UInt64Value* UInt64Value::New(::google::protobuf::Arena* arena) const {
-  UInt64Value* n = new UInt64Value;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<UInt64Value>(arena);
 }
 
 void UInt64Value::Clear() {
@@ -1171,6 +1264,18 @@ bool UInt64Value::IsInitialized() const {
 
 void UInt64Value::Swap(UInt64Value* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    UInt64Value temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void UInt64Value::UnsafeArenaSwap(UInt64Value* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void UInt64Value::InternalSwap(UInt64Value* other) {
@@ -1218,6 +1323,14 @@ Int32Value::Int32Value()
   // @@protoc_insertion_point(constructor:google.protobuf.Int32Value)
 }
 
+Int32Value::Int32Value(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.Int32Value)
+}
+
 void Int32Value::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -1242,10 +1355,20 @@ Int32Value::~Int32Value() {
 }
 
 void Int32Value::SharedDtor() {
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
   if (this != default_instance_) {
   }
 }
 
+void Int32Value::ArenaDtor(void* object) {
+  Int32Value* _this = reinterpret_cast< Int32Value* >(object);
+  (void)_this;
+}
+void Int32Value::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void Int32Value::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -1264,11 +1387,7 @@ const Int32Value& Int32Value::default_instance() {
 Int32Value* Int32Value::default_instance_ = NULL;
 
 Int32Value* Int32Value::New(::google::protobuf::Arena* arena) const {
-  Int32Value* n = new Int32Value;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<Int32Value>(arena);
 }
 
 void Int32Value::Clear() {
@@ -1397,6 +1516,18 @@ bool Int32Value::IsInitialized() const {
 
 void Int32Value::Swap(Int32Value* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    Int32Value temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void Int32Value::UnsafeArenaSwap(Int32Value* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void Int32Value::InternalSwap(Int32Value* other) {
@@ -1444,6 +1575,14 @@ UInt32Value::UInt32Value()
   // @@protoc_insertion_point(constructor:google.protobuf.UInt32Value)
 }
 
+UInt32Value::UInt32Value(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.UInt32Value)
+}
+
 void UInt32Value::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -1468,10 +1607,20 @@ UInt32Value::~UInt32Value() {
 }
 
 void UInt32Value::SharedDtor() {
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
   if (this != default_instance_) {
   }
 }
 
+void UInt32Value::ArenaDtor(void* object) {
+  UInt32Value* _this = reinterpret_cast< UInt32Value* >(object);
+  (void)_this;
+}
+void UInt32Value::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void UInt32Value::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -1490,11 +1639,7 @@ const UInt32Value& UInt32Value::default_instance() {
 UInt32Value* UInt32Value::default_instance_ = NULL;
 
 UInt32Value* UInt32Value::New(::google::protobuf::Arena* arena) const {
-  UInt32Value* n = new UInt32Value;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<UInt32Value>(arena);
 }
 
 void UInt32Value::Clear() {
@@ -1623,6 +1768,18 @@ bool UInt32Value::IsInitialized() const {
 
 void UInt32Value::Swap(UInt32Value* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    UInt32Value temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void UInt32Value::UnsafeArenaSwap(UInt32Value* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void UInt32Value::InternalSwap(UInt32Value* other) {
@@ -1670,6 +1827,14 @@ BoolValue::BoolValue()
   // @@protoc_insertion_point(constructor:google.protobuf.BoolValue)
 }
 
+BoolValue::BoolValue(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.BoolValue)
+}
+
 void BoolValue::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -1694,10 +1859,20 @@ BoolValue::~BoolValue() {
 }
 
 void BoolValue::SharedDtor() {
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
   if (this != default_instance_) {
   }
 }
 
+void BoolValue::ArenaDtor(void* object) {
+  BoolValue* _this = reinterpret_cast< BoolValue* >(object);
+  (void)_this;
+}
+void BoolValue::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void BoolValue::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -1716,11 +1891,7 @@ const BoolValue& BoolValue::default_instance() {
 BoolValue* BoolValue::default_instance_ = NULL;
 
 BoolValue* BoolValue::New(::google::protobuf::Arena* arena) const {
-  BoolValue* n = new BoolValue;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<BoolValue>(arena);
 }
 
 void BoolValue::Clear() {
@@ -1847,6 +2018,18 @@ bool BoolValue::IsInitialized() const {
 
 void BoolValue::Swap(BoolValue* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    BoolValue temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void BoolValue::UnsafeArenaSwap(BoolValue* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void BoolValue::InternalSwap(BoolValue* other) {
@@ -1894,6 +2077,14 @@ StringValue::StringValue()
   // @@protoc_insertion_point(constructor:google.protobuf.StringValue)
 }
 
+StringValue::StringValue(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.StringValue)
+}
+
 void StringValue::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -1919,11 +2110,21 @@ StringValue::~StringValue() {
 }
 
 void StringValue::SharedDtor() {
-  value_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
+  value_.Destroy(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
   if (this != default_instance_) {
   }
 }
 
+void StringValue::ArenaDtor(void* object) {
+  StringValue* _this = reinterpret_cast< StringValue* >(object);
+  (void)_this;
+}
+void StringValue::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void StringValue::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -1942,15 +2143,11 @@ const StringValue& StringValue::default_instance() {
 StringValue* StringValue::default_instance_ = NULL;
 
 StringValue* StringValue::New(::google::protobuf::Arena* arena) const {
-  StringValue* n = new StringValue;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<StringValue>(arena);
 }
 
 void StringValue::Clear() {
-  value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  value_.ClearToEmpty(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 
 bool StringValue::MergePartialFromCodedStream(
@@ -2065,8 +2262,7 @@ void StringValue::MergeFrom(const ::google::protobuf::Message& from) {
 void StringValue::MergeFrom(const StringValue& from) {
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value().size() > 0) {
-
-    value_.AssignWithDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), from.value_);
+    set_value(from.value());
   }
 }
 
@@ -2089,6 +2285,18 @@ bool StringValue::IsInitialized() const {
 
 void StringValue::Swap(StringValue* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    StringValue temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void StringValue::UnsafeArenaSwap(StringValue* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void StringValue::InternalSwap(StringValue* other) {
@@ -2110,36 +2318,44 @@ void StringValue::InternalSwap(StringValue* other) {
 
 // optional string value = 1;
 void StringValue::clear_value() {
-  value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  value_.ClearToEmpty(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
  const ::std::string& StringValue::value() const {
   // @@protoc_insertion_point(field_get:google.protobuf.StringValue.value)
-  return value_.GetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Get(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  void StringValue::set_value(const ::std::string& value) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value, GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set:google.protobuf.StringValue.value)
 }
  void StringValue::set_value(const char* value) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value));
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value),
+              GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_char:google.protobuf.StringValue.value)
 }
- void StringValue::set_value(const char* value, size_t size) {
+ void StringValue::set_value(const char* value,
+    size_t size) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
-      ::std::string(reinterpret_cast<const char*>(value), size));
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(
+      reinterpret_cast<const char*>(value), size), GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.StringValue.value)
 }
  ::std::string* StringValue::mutable_value() {
   
   // @@protoc_insertion_point(field_mutable:google.protobuf.StringValue.value)
-  return value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Mutable(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
  ::std::string* StringValue::release_value() {
   
-  return value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Release(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
+}
+ ::std::string* StringValue::unsafe_arena_release_value() {
+  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
+  
+  return value_.UnsafeArenaRelease(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      GetArenaNoVirtual());
 }
  void StringValue::set_allocated_value(::std::string* value) {
   if (value != NULL) {
@@ -2147,7 +2363,20 @@ void StringValue::clear_value() {
   } else {
     
   }
-  value_.SetAllocatedNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  value_.SetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value,
+      GetArenaNoVirtual());
+  // @@protoc_insertion_point(field_set_allocated:google.protobuf.StringValue.value)
+}
+ void StringValue::unsafe_arena_set_allocated_value(
+    ::std::string* value) {
+  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
+  if (value != NULL) {
+    
+  } else {
+    
+  }
+  value_.UnsafeArenaSetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      value, GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.StringValue.value)
 }
 
@@ -2165,6 +2394,14 @@ BytesValue::BytesValue()
   // @@protoc_insertion_point(constructor:google.protobuf.BytesValue)
 }
 
+BytesValue::BytesValue(::google::protobuf::Arena* arena)
+  : ::google::protobuf::Message(),
+  _internal_metadata_(arena) {
+  SharedCtor();
+  RegisterArenaDtor(arena);
+  // @@protoc_insertion_point(arena_constructor:google.protobuf.BytesValue)
+}
+
 void BytesValue::InitAsDefaultInstance() {
   _is_default_instance_ = true;
 }
@@ -2190,11 +2427,21 @@ BytesValue::~BytesValue() {
 }
 
 void BytesValue::SharedDtor() {
-  value_.DestroyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  if (GetArenaNoVirtual() != NULL) {
+    return;
+  }
+
+  value_.Destroy(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
   if (this != default_instance_) {
   }
 }
 
+void BytesValue::ArenaDtor(void* object) {
+  BytesValue* _this = reinterpret_cast< BytesValue* >(object);
+  (void)_this;
+}
+void BytesValue::RegisterArenaDtor(::google::protobuf::Arena* arena) {
+}
 void BytesValue::SetCachedSize(int size) const {
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
   _cached_size_ = size;
@@ -2213,15 +2460,11 @@ const BytesValue& BytesValue::default_instance() {
 BytesValue* BytesValue::default_instance_ = NULL;
 
 BytesValue* BytesValue::New(::google::protobuf::Arena* arena) const {
-  BytesValue* n = new BytesValue;
-  if (arena != NULL) {
-    arena->Own(n);
-  }
-  return n;
+  return ::google::protobuf::Arena::CreateMessage<BytesValue>(arena);
 }
 
 void BytesValue::Clear() {
-  value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  value_.ClearToEmpty(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 
 bool BytesValue::MergePartialFromCodedStream(
@@ -2324,8 +2567,7 @@ void BytesValue::MergeFrom(const ::google::protobuf::Message& from) {
 void BytesValue::MergeFrom(const BytesValue& from) {
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value().size() > 0) {
-
-    value_.AssignWithDefault(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), from.value_);
+    set_value(from.value());
   }
 }
 
@@ -2348,6 +2590,18 @@ bool BytesValue::IsInitialized() const {
 
 void BytesValue::Swap(BytesValue* other) {
   if (other == this) return;
+  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {
+    InternalSwap(other);
+  } else {
+    BytesValue temp;
+    temp.MergeFrom(*this);
+    CopyFrom(*other);
+    other->CopyFrom(temp);
+  }
+}
+void BytesValue::UnsafeArenaSwap(BytesValue* other) {
+  if (other == this) return;
+  GOOGLE_DCHECK(GetArenaNoVirtual() == other->GetArenaNoVirtual());
   InternalSwap(other);
 }
 void BytesValue::InternalSwap(BytesValue* other) {
@@ -2369,36 +2623,44 @@ void BytesValue::InternalSwap(BytesValue* other) {
 
 // optional bytes value = 1;
 void BytesValue::clear_value() {
-  value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  value_.ClearToEmpty(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
  const ::std::string& BytesValue::value() const {
   // @@protoc_insertion_point(field_get:google.protobuf.BytesValue.value)
-  return value_.GetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Get(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  void BytesValue::set_value(const ::std::string& value) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value, GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set:google.protobuf.BytesValue.value)
 }
  void BytesValue::set_value(const char* value) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value));
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value),
+              GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_char:google.protobuf.BytesValue.value)
 }
- void BytesValue::set_value(const void* value, size_t size) {
+ void BytesValue::set_value(const void* value,
+    size_t size) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
-      ::std::string(reinterpret_cast<const char*>(value), size));
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(
+      reinterpret_cast<const char*>(value), size), GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.BytesValue.value)
 }
  ::std::string* BytesValue::mutable_value() {
   
   // @@protoc_insertion_point(field_mutable:google.protobuf.BytesValue.value)
-  return value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Mutable(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
  ::std::string* BytesValue::release_value() {
   
-  return value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Release(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
+}
+ ::std::string* BytesValue::unsafe_arena_release_value() {
+  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
+  
+  return value_.UnsafeArenaRelease(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      GetArenaNoVirtual());
 }
  void BytesValue::set_allocated_value(::std::string* value) {
   if (value != NULL) {
@@ -2406,7 +2668,20 @@ void BytesValue::clear_value() {
   } else {
     
   }
-  value_.SetAllocatedNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  value_.SetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value,
+      GetArenaNoVirtual());
+  // @@protoc_insertion_point(field_set_allocated:google.protobuf.BytesValue.value)
+}
+ void BytesValue::unsafe_arena_set_allocated_value(
+    ::std::string* value) {
+  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
+  if (value != NULL) {
+    
+  } else {
+    
+  }
+  value_.UnsafeArenaSetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      value, GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.BytesValue.value)
 }
 
diff --git a/src/google/protobuf/wrappers.pb.h b/src/google/protobuf/wrappers.pb.h
index 15bcc7a2..7dca938c 100644
--- a/src/google/protobuf/wrappers.pb.h
+++ b/src/google/protobuf/wrappers.pb.h
@@ -61,9 +61,14 @@ class LIBPROTOBUF_EXPORT DoubleValue : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const DoubleValue& default_instance();
 
+  void UnsafeArenaSwap(DoubleValue* other);
   void Swap(DoubleValue* other);
 
   // implements Message ----------------------------------------------
@@ -90,6 +95,11 @@ class LIBPROTOBUF_EXPORT DoubleValue : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(DoubleValue* other);
+  protected:
+  explicit DoubleValue(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -115,6 +125,9 @@ class LIBPROTOBUF_EXPORT DoubleValue : public ::google::protobuf::Message {
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   double value_;
   mutable int _cached_size_;
@@ -139,9 +152,14 @@ class LIBPROTOBUF_EXPORT FloatValue : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const FloatValue& default_instance();
 
+  void UnsafeArenaSwap(FloatValue* other);
   void Swap(FloatValue* other);
 
   // implements Message ----------------------------------------------
@@ -168,6 +186,11 @@ class LIBPROTOBUF_EXPORT FloatValue : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(FloatValue* other);
+  protected:
+  explicit FloatValue(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -193,6 +216,9 @@ class LIBPROTOBUF_EXPORT FloatValue : public ::google::protobuf::Message {
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   float value_;
   mutable int _cached_size_;
@@ -217,9 +243,14 @@ class LIBPROTOBUF_EXPORT Int64Value : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const Int64Value& default_instance();
 
+  void UnsafeArenaSwap(Int64Value* other);
   void Swap(Int64Value* other);
 
   // implements Message ----------------------------------------------
@@ -246,6 +277,11 @@ class LIBPROTOBUF_EXPORT Int64Value : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(Int64Value* other);
+  protected:
+  explicit Int64Value(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -271,6 +307,9 @@ class LIBPROTOBUF_EXPORT Int64Value : public ::google::protobuf::Message {
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   ::google::protobuf::int64 value_;
   mutable int _cached_size_;
@@ -295,9 +334,14 @@ class LIBPROTOBUF_EXPORT UInt64Value : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const UInt64Value& default_instance();
 
+  void UnsafeArenaSwap(UInt64Value* other);
   void Swap(UInt64Value* other);
 
   // implements Message ----------------------------------------------
@@ -324,6 +368,11 @@ class LIBPROTOBUF_EXPORT UInt64Value : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(UInt64Value* other);
+  protected:
+  explicit UInt64Value(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -349,6 +398,9 @@ class LIBPROTOBUF_EXPORT UInt64Value : public ::google::protobuf::Message {
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   ::google::protobuf::uint64 value_;
   mutable int _cached_size_;
@@ -373,9 +425,14 @@ class LIBPROTOBUF_EXPORT Int32Value : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const Int32Value& default_instance();
 
+  void UnsafeArenaSwap(Int32Value* other);
   void Swap(Int32Value* other);
 
   // implements Message ----------------------------------------------
@@ -402,6 +459,11 @@ class LIBPROTOBUF_EXPORT Int32Value : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(Int32Value* other);
+  protected:
+  explicit Int32Value(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -427,6 +489,9 @@ class LIBPROTOBUF_EXPORT Int32Value : public ::google::protobuf::Message {
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   ::google::protobuf::int32 value_;
   mutable int _cached_size_;
@@ -451,9 +516,14 @@ class LIBPROTOBUF_EXPORT UInt32Value : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const UInt32Value& default_instance();
 
+  void UnsafeArenaSwap(UInt32Value* other);
   void Swap(UInt32Value* other);
 
   // implements Message ----------------------------------------------
@@ -480,6 +550,11 @@ class LIBPROTOBUF_EXPORT UInt32Value : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(UInt32Value* other);
+  protected:
+  explicit UInt32Value(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -505,6 +580,9 @@ class LIBPROTOBUF_EXPORT UInt32Value : public ::google::protobuf::Message {
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   ::google::protobuf::uint32 value_;
   mutable int _cached_size_;
@@ -529,9 +607,14 @@ class LIBPROTOBUF_EXPORT BoolValue : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const BoolValue& default_instance();
 
+  void UnsafeArenaSwap(BoolValue* other);
   void Swap(BoolValue* other);
 
   // implements Message ----------------------------------------------
@@ -558,6 +641,11 @@ class LIBPROTOBUF_EXPORT BoolValue : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(BoolValue* other);
+  protected:
+  explicit BoolValue(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -583,6 +671,9 @@ class LIBPROTOBUF_EXPORT BoolValue : public ::google::protobuf::Message {
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   bool value_;
   mutable int _cached_size_;
@@ -607,9 +698,14 @@ class LIBPROTOBUF_EXPORT StringValue : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const StringValue& default_instance();
 
+  void UnsafeArenaSwap(StringValue* other);
   void Swap(StringValue* other);
 
   // implements Message ----------------------------------------------
@@ -636,6 +732,11 @@ class LIBPROTOBUF_EXPORT StringValue : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(StringValue* other);
+  protected:
+  explicit StringValue(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -661,11 +762,17 @@ class LIBPROTOBUF_EXPORT StringValue : public ::google::protobuf::Message {
   ::std::string* mutable_value();
   ::std::string* release_value();
   void set_allocated_value(::std::string* value);
+  ::std::string* unsafe_arena_release_value();
+  void unsafe_arena_set_allocated_value(
+      ::std::string* value);
 
   // @@protoc_insertion_point(class_scope:google.protobuf.StringValue)
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   ::google::protobuf::internal::ArenaStringPtr value_;
   mutable int _cached_size_;
@@ -690,9 +797,14 @@ class LIBPROTOBUF_EXPORT BytesValue : public ::google::protobuf::Message {
     return *this;
   }
 
+  inline ::google::protobuf::Arena* GetArena() const { return GetArenaNoVirtual(); }
+  inline void* GetMaybeArenaPointer() const {
+    return MaybeArenaPtr();
+  }
   static const ::google::protobuf::Descriptor* descriptor();
   static const BytesValue& default_instance();
 
+  void UnsafeArenaSwap(BytesValue* other);
   void Swap(BytesValue* other);
 
   // implements Message ----------------------------------------------
@@ -719,6 +831,11 @@ class LIBPROTOBUF_EXPORT BytesValue : public ::google::protobuf::Message {
   void SharedDtor();
   void SetCachedSize(int size) const;
   void InternalSwap(BytesValue* other);
+  protected:
+  explicit BytesValue(::google::protobuf::Arena* arena);
+  private:
+  static void ArenaDtor(void* object);
+  inline void RegisterArenaDtor(::google::protobuf::Arena* arena);
   private:
   inline ::google::protobuf::Arena* GetArenaNoVirtual() const {
     return _internal_metadata_.arena();
@@ -744,11 +861,17 @@ class LIBPROTOBUF_EXPORT BytesValue : public ::google::protobuf::Message {
   ::std::string* mutable_value();
   ::std::string* release_value();
   void set_allocated_value(::std::string* value);
+  ::std::string* unsafe_arena_release_value();
+  void unsafe_arena_set_allocated_value(
+      ::std::string* value);
 
   // @@protoc_insertion_point(class_scope:google.protobuf.BytesValue)
  private:
 
   ::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;
+  friend class ::google::protobuf::Arena;
+  typedef void InternalArenaConstructable_;
+  typedef void DestructorSkippable_;
   bool _is_default_instance_;
   ::google::protobuf::internal::ArenaStringPtr value_;
   mutable int _cached_size_;
@@ -895,36 +1018,44 @@ inline void BoolValue::set_value(bool value) {
 
 // optional string value = 1;
 inline void StringValue::clear_value() {
-  value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  value_.ClearToEmpty(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 inline const ::std::string& StringValue::value() const {
   // @@protoc_insertion_point(field_get:google.protobuf.StringValue.value)
-  return value_.GetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Get(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline void StringValue::set_value(const ::std::string& value) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value, GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set:google.protobuf.StringValue.value)
 }
 inline void StringValue::set_value(const char* value) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value));
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value),
+              GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_char:google.protobuf.StringValue.value)
 }
-inline void StringValue::set_value(const char* value, size_t size) {
+inline void StringValue::set_value(const char* value,
+    size_t size) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
-      ::std::string(reinterpret_cast<const char*>(value), size));
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(
+      reinterpret_cast<const char*>(value), size), GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.StringValue.value)
 }
 inline ::std::string* StringValue::mutable_value() {
   
   // @@protoc_insertion_point(field_mutable:google.protobuf.StringValue.value)
-  return value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Mutable(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 inline ::std::string* StringValue::release_value() {
   
-  return value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Release(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
+}
+inline ::std::string* StringValue::unsafe_arena_release_value() {
+  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
+  
+  return value_.UnsafeArenaRelease(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      GetArenaNoVirtual());
 }
 inline void StringValue::set_allocated_value(::std::string* value) {
   if (value != NULL) {
@@ -932,7 +1063,20 @@ inline void StringValue::set_allocated_value(::std::string* value) {
   } else {
     
   }
-  value_.SetAllocatedNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  value_.SetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value,
+      GetArenaNoVirtual());
+  // @@protoc_insertion_point(field_set_allocated:google.protobuf.StringValue.value)
+}
+inline void StringValue::unsafe_arena_set_allocated_value(
+    ::std::string* value) {
+  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
+  if (value != NULL) {
+    
+  } else {
+    
+  }
+  value_.UnsafeArenaSetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      value, GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.StringValue.value)
 }
 
@@ -942,36 +1086,44 @@ inline void StringValue::set_allocated_value(::std::string* value) {
 
 // optional bytes value = 1;
 inline void BytesValue::clear_value() {
-  value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  value_.ClearToEmpty(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 inline const ::std::string& BytesValue::value() const {
   // @@protoc_insertion_point(field_get:google.protobuf.BytesValue.value)
-  return value_.GetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Get(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline void BytesValue::set_value(const ::std::string& value) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value, GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set:google.protobuf.BytesValue.value)
 }
 inline void BytesValue::set_value(const char* value) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value));
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(value),
+              GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_char:google.protobuf.BytesValue.value)
 }
-inline void BytesValue::set_value(const void* value, size_t size) {
+inline void BytesValue::set_value(const void* value,
+    size_t size) {
   
-  value_.SetNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
-      ::std::string(reinterpret_cast<const char*>(value), size));
+  value_.Set(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), ::std::string(
+      reinterpret_cast<const char*>(value), size), GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.BytesValue.value)
 }
 inline ::std::string* BytesValue::mutable_value() {
   
   // @@protoc_insertion_point(field_mutable:google.protobuf.BytesValue.value)
-  return value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Mutable(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 inline ::std::string* BytesValue::release_value() {
   
-  return value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
+  return value_.Release(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
+}
+inline ::std::string* BytesValue::unsafe_arena_release_value() {
+  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
+  
+  return value_.UnsafeArenaRelease(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      GetArenaNoVirtual());
 }
 inline void BytesValue::set_allocated_value(::std::string* value) {
   if (value != NULL) {
@@ -979,7 +1131,20 @@ inline void BytesValue::set_allocated_value(::std::string* value) {
   } else {
     
   }
-  value_.SetAllocatedNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value);
+  value_.SetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), value,
+      GetArenaNoVirtual());
+  // @@protoc_insertion_point(field_set_allocated:google.protobuf.BytesValue.value)
+}
+inline void BytesValue::unsafe_arena_set_allocated_value(
+    ::std::string* value) {
+  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
+  if (value != NULL) {
+    
+  } else {
+    
+  }
+  value_.UnsafeArenaSetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
+      value, GetArenaNoVirtual());
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.BytesValue.value)
 }
 
diff --git a/src/google/protobuf/wrappers.proto b/src/google/protobuf/wrappers.proto
index a1d6e446..040d8a24 100644
--- a/src/google/protobuf/wrappers.proto
+++ b/src/google/protobuf/wrappers.proto
@@ -37,11 +37,12 @@ syntax = "proto3";
 
 package google.protobuf;
 
-option java_generate_equals_and_hash = true;
-option java_multiple_files = true;
-option java_outer_classname = "WrappersProto";
-option java_package = "com.google.protobuf";
 option csharp_namespace = "Google.Protobuf.WellKnownTypes";
+option cc_enable_arenas = true;
+option java_package = "com.google.protobuf";
+option java_outer_classname = "WrappersProto";
+option java_multiple_files = true;
+option java_generate_equals_and_hash = true;
 option objc_class_prefix = "GPB";
 
 // Wrapper message for `double`.