Objective C Second Alpha Drop

- Style fixups in the code.
- map<> serialization fixes and more tests.
- Autocreation of map<> fields (to match repeated fields).
- @@protoc_insertion_point(global_scope|imports).
- Fixup proto2 syntax extension support.
- Move all startup code to +initialize so it happen on class usage and not app startup.
- Have generated headers use forward declarations and move imports into generated code, reduces what is need at compile time to speed up compiled and avoid pointless rippling of rebuilds.

20 files changed, 223 insertions, 101 deletions

diff --git a/src/google/protobuf/compiler/objectivec/objectivec_enum.h b/src/google/protobuf/compiler/objectivec/objectivec_enum.h
index 2dc5547b..0b41cf73 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_enum.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_enum.h
@@ -49,7 +49,7 @@ namespace objectivec {
 
 class EnumGenerator {
  public:
-  EnumGenerator(const EnumDescriptor* descriptor);
+  explicit EnumGenerator(const EnumDescriptor* descriptor);
   ~EnumGenerator();
 
   void GenerateHeader(io::Printer* printer);
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_enum_field.cc b/src/google/protobuf/compiler/objectivec/objectivec_enum_field.cc
index 739282b2..d6609692 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_enum_field.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_enum_field.cc
@@ -48,6 +48,13 @@ void SetEnumVariables(const FieldDescriptor* descriptor,
                       map<string, string>* variables) {
   string type = EnumName(descriptor->enum_type());
   (*variables)["storage_type"] = type;
+  // For non repeated fields, if it was defined in a different file, the
+  // property decls need to use "enum NAME" rather than just "NAME" to support
+  // the forward declaration of the enums.
+  if (!descriptor->is_repeated() &&
+      (descriptor->file() != descriptor->enum_type()->file())) {
+    (*variables)["property_type"] = "enum " + type;
+  }
   // TODO(thomasvl): Make inclusion of descriptor compile time and output
   // both of these. Note: Extensions currently have to have the EnumDescription.
   (*variables)["enum_verifier"] = type + "_IsValidValue";
@@ -76,7 +83,9 @@ void EnumFieldGenerator::GenerateFieldDescriptionTypeSpecific(
 
 void EnumFieldGenerator::GenerateCFunctionDeclarations(
     io::Printer* printer) const {
-  if (!HasPreservingUnknownEnumSemantics(descriptor_->file())) return;
+  if (!HasPreservingUnknownEnumSemantics(descriptor_->file())) {
+    return;
+  }
 
   printer->Print(
       variables_,
@@ -105,6 +114,18 @@ void EnumFieldGenerator::GenerateCFunctionImplementations(
       "\n");
 }
 
+void EnumFieldGenerator::DetermineForwardDeclarations(
+    set<string>* fwd_decls) const {
+  // If it is an enum defined in a different file, then we'll need a forward
+  // declaration for it.  When it is in our file, all the enums are output
+  // before the message, so it will be declared before it is needed.
+  if (descriptor_->file() != descriptor_->enum_type()->file()) {
+    // Enum name is already in "storage_type".
+    const string& name = variable("storage_type");
+    fwd_decls->insert("GPB_ENUM_FWD_DECLARE(" + name + ")");
+  }
+}
+
 RepeatedEnumFieldGenerator::RepeatedEnumFieldGenerator(
     const FieldDescriptor* descriptor)
     : RepeatedFieldGenerator(descriptor) {
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_enum_field.h b/src/google/protobuf/compiler/objectivec/objectivec_enum_field.h
index 2d5822bb..b629eae8 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_enum_field.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_enum_field.h
@@ -47,9 +47,10 @@ class EnumFieldGenerator : public SingleFieldGenerator {
   virtual void GenerateFieldDescriptionTypeSpecific(io::Printer* printer) const;
   virtual void GenerateCFunctionDeclarations(io::Printer* printer) const;
   virtual void GenerateCFunctionImplementations(io::Printer* printer) const;
+  virtual void DetermineForwardDeclarations(set<string>* fwd_decls) const;
 
  protected:
-  EnumFieldGenerator(const FieldDescriptor* descriptor);
+  explicit EnumFieldGenerator(const FieldDescriptor* descriptor);
   virtual ~EnumFieldGenerator();
 
  private:
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_extension.cc b/src/google/protobuf/compiler/objectivec/objectivec_extension.cc
index 0574cca2..76137c80 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_extension.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_extension.cc
@@ -66,7 +66,7 @@ ExtensionGenerator::ExtensionGenerator(const string& root_class_name,
   }
   if (descriptor->is_map()) {
     // NOTE: src/google/protobuf/compiler/plugin.cc makes use of cerr for some
-    // error case, so it seem to be ok to use as a back door for errors.
+    // error cases, so it seems to be ok to use as a back door for errors.
     cerr << "error: Extension is a map<>!"
          << " That used to be blocked by the compiler." << endl;
     cerr.flush();
@@ -107,7 +107,7 @@ void ExtensionGenerator::GenerateStaticVariablesInitialization(
 
   std::vector<string> options;
   if (descriptor_->is_repeated()) options.push_back("GPBExtensionRepeated");
-  if (descriptor_->options().packed()) options.push_back("GPBExtensionPacked");
+  if (descriptor_->is_packed()) options.push_back("GPBExtensionPacked");
   if (descriptor_->containing_type()->options().message_set_wire_format())
     options.push_back("GPBExtensionSetWireFormat");
 
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_extension.h b/src/google/protobuf/compiler/objectivec/objectivec_extension.h
index d17f5be9..553f0887 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_extension.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_extension.h
@@ -47,8 +47,8 @@ namespace objectivec {
 
 class ExtensionGenerator {
  public:
-  explicit ExtensionGenerator(const string& root_class_name,
-                              const FieldDescriptor* descriptor);
+  ExtensionGenerator(const string& root_class_name,
+                     const FieldDescriptor* descriptor);
   ~ExtensionGenerator();
 
   void GenerateMembersHeader(io::Printer* printer);
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_field.cc b/src/google/protobuf/compiler/objectivec/objectivec_field.cc
index 93fffe0e..ee5253a5 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_field.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_field.cc
@@ -80,7 +80,7 @@ void SetCommonFieldVariables(const FieldDescriptor* descriptor,
   if (descriptor->is_repeated()) field_flags.push_back("GPBFieldRepeated");
   if (descriptor->is_required()) field_flags.push_back("GPBFieldRequired");
   if (descriptor->is_optional()) field_flags.push_back("GPBFieldOptional");
-  if (descriptor->options().packed()) field_flags.push_back("GPBFieldPacked");
+  if (descriptor->is_packed()) field_flags.push_back("GPBFieldPacked");
 
   // ObjC custom flags.
   if (descriptor->has_default_value())
@@ -235,6 +235,11 @@ void FieldGenerator::GenerateCFunctionImplementations(
   // Nothing
 }
 
+void FieldGenerator::DetermineForwardDeclarations(
+    set<string>* fwd_decls) const {
+  // Nothing
+}
+
 void FieldGenerator::GenerateFieldDescription(
     io::Printer* printer) const {
   printer->Print(
@@ -282,12 +287,16 @@ void FieldGenerator::SetOneofIndexBase(int index_base) {
   if (descriptor_->containing_oneof() != NULL) {
     int index = descriptor_->containing_oneof()->index() + index_base;
     // Flip the sign to mark it as a oneof.
-    variables_["has_index"] = SimpleItoa(-index);;
+    variables_["has_index"] = SimpleItoa(-index);
   }
 }
 
 void FieldGenerator::FinishInitialization(void) {
-  // Nothing
+  // If "property_type" wasn't set, make it "storage_type".
+  if ((variables_.find("property_type") == variables_.end()) &&
+      (variables_.find("storage_type") != variables_.end())) {
+    variables_["property_type"] = variable("storage_type");
+  }
 }
 
 SingleFieldGenerator::SingleFieldGenerator(
@@ -313,7 +322,7 @@ void SingleFieldGenerator::GeneratePropertyDeclaration(
   }
   printer->Print(
       variables_,
-      "@property(nonatomic, readwrite) $storage_type$ $name$;\n"
+      "@property(nonatomic, readwrite) $property_type$ $name$;\n"
       "\n");
 }
 
@@ -369,12 +378,12 @@ void ObjCObjFieldGenerator::GeneratePropertyDeclaration(
   }
   printer->Print(
       variables_,
-      "@property(nonatomic, readwrite, $property_storage_attribute$) $storage_type$ *$name$$storage_attribute$;\n");
+      "@property(nonatomic, readwrite, $property_storage_attribute$) $property_type$ *$name$$storage_attribute$;\n");
   if (IsInitName(variables_.at("name"))) {
     // If property name starts with init we need to annotate it to get past ARC.
     // http://stackoverflow.com/questions/18723226/how-do-i-annotate-an-objective-c-property-with-an-objc-method-family/18723227#18723227
     printer->Print(variables_,
-                   "- ($storage_type$ *)$name$ GPB_METHOD_FAMILY_NONE;\n");
+                   "- ($property_type$ *)$name$ GPB_METHOD_FAMILY_NONE;\n");
   }
   printer->Print("\n");
 }
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_field.h b/src/google/protobuf/compiler/objectivec/objectivec_field.h
index c65e73b2..130a52dd 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_field.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_field.h
@@ -65,6 +65,8 @@ class FieldGenerator {
   virtual void GenerateCFunctionDeclarations(io::Printer* printer) const;
   virtual void GenerateCFunctionImplementations(io::Printer* printer) const;
 
+  virtual void DetermineForwardDeclarations(set<string>* fwd_decls) const;
+
   void SetOneofIndexBase(int index_base);
 
   string variable(const char* key) const {
@@ -79,7 +81,7 @@ class FieldGenerator {
   string raw_field_name() const { return variable("raw_field_name"); }
 
  protected:
-  FieldGenerator(const FieldDescriptor* descriptor);
+  explicit FieldGenerator(const FieldDescriptor* descriptor);
 
   virtual void FinishInitialization(void);
   virtual bool WantsHasProperty(void) const = 0;
@@ -101,7 +103,7 @@ class SingleFieldGenerator : public FieldGenerator {
   virtual void GeneratePropertyImplementation(io::Printer* printer) const;
 
  protected:
-  SingleFieldGenerator(const FieldDescriptor* descriptor);
+  explicit SingleFieldGenerator(const FieldDescriptor* descriptor);
   virtual bool WantsHasProperty(void) const;
 
  private:
@@ -117,7 +119,7 @@ class ObjCObjFieldGenerator : public SingleFieldGenerator {
   virtual void GeneratePropertyDeclaration(io::Printer* printer) const;
 
  protected:
-  ObjCObjFieldGenerator(const FieldDescriptor* descriptor);
+  explicit ObjCObjFieldGenerator(const FieldDescriptor* descriptor);
 
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ObjCObjFieldGenerator);
@@ -133,7 +135,7 @@ class RepeatedFieldGenerator : public ObjCObjFieldGenerator {
   virtual void GeneratePropertyImplementation(io::Printer* printer) const;
 
  protected:
-  RepeatedFieldGenerator(const FieldDescriptor* descriptor);
+  explicit RepeatedFieldGenerator(const FieldDescriptor* descriptor);
   virtual void FinishInitialization(void);
   virtual bool WantsHasProperty(void) const;
 
@@ -144,7 +146,7 @@ class RepeatedFieldGenerator : public ObjCObjFieldGenerator {
 // Convenience class which constructs FieldGenerators for a Descriptor.
 class FieldGeneratorMap {
  public:
-  FieldGeneratorMap(const Descriptor* descriptor);
+  explicit FieldGeneratorMap(const Descriptor* descriptor);
   ~FieldGeneratorMap();
 
   const FieldGenerator& get(const FieldDescriptor* field) const;
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_file.cc b/src/google/protobuf/compiler/objectivec/objectivec_file.cc
index b3ad448e..d04eee85 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_file.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_file.cc
@@ -50,11 +50,17 @@ const int32 GOOGLE_PROTOBUF_OBJC_GEN_VERSION = 30000;
 
 namespace compiler {
 namespace objectivec {
+
 FileGenerator::FileGenerator(const FileDescriptor *file)
     : file_(file),
       root_class_name_(FileClassName(file)),
       is_filtered_(true),
-      all_extensions_filtered_(true) {
+      all_extensions_filtered_(true),
+      is_public_dep_(false) {
+  // Validate the objc prefix, do this even if the file's contents are filtered
+  // to catch a bad prefix as soon as it is found.
+  ValidateObjCClassPrefix(file_);
+
   for (int i = 0; i < file_->enum_type_count(); i++) {
     EnumGenerator *generator = new EnumGenerator(file_->enum_type(i));
     // The enums are exposed via C functions, so they will dead strip if
@@ -96,7 +102,9 @@ void FileGenerator::GenerateHeader(io::Printer *printer) {
       "\n",
       "filename", file_->name());
 
-  printer->Print("#import \"GPBProtocolBuffers.h\"\n\n");
+  printer->Print(
+      "#import \"GPBProtocolBuffers.h\"\n"
+      "\n");
 
   // Add some verification that the generated code matches the source the
   // code is being compiled with.
@@ -108,31 +116,34 @@ void FileGenerator::GenerateHeader(io::Printer *printer) {
       "protoc_gen_objc_version",
       SimpleItoa(GOOGLE_PROTOBUF_OBJC_GEN_VERSION));
 
-  if (!IsFiltered()) {
-    const vector<FileGenerator *> &dependency_generators =
-        DependencyGenerators();
-    if (dependency_generators.size() > 0) {
-      for (vector<FileGenerator *>::const_iterator iter =
-               dependency_generators.begin();
-           iter != dependency_generators.end(); ++iter) {
-        printer->Print("#import \"$header$.pbobjc.h\"\n",
-                       "header", (*iter)->Path());
-      }
-      printer->Print("\n");
+  const vector<FileGenerator *> &dependency_generators =
+      DependencyGenerators();
+  for (vector<FileGenerator *>::const_iterator iter =
+           dependency_generators.begin();
+       iter != dependency_generators.end(); ++iter) {
+    if ((*iter)->IsPublicDependency()) {
+      printer->Print("#import \"$header$.pbobjc.h\"\n",
+                     "header", (*iter)->Path());
     }
   }
 
+  printer->Print(
+      "// @@protoc_insertion_point(imports)\n"
+      "\n");
+
   printer->Print("CF_EXTERN_C_BEGIN\n\n");
 
   if (!IsFiltered()) {
-    set<string> dependencies;
-    DetermineDependencies(&dependencies);
-    for (set<string>::const_iterator i(dependencies.begin());
-         i != dependencies.end(); ++i) {
+    set<string> fwd_decls;
+    for (vector<MessageGenerator *>::iterator iter = message_generators_.begin();
+         iter != message_generators_.end(); ++iter) {
+      (*iter)->DetermineForwardDeclarations(&fwd_decls);
+    }
+    for (set<string>::const_iterator i(fwd_decls.begin());
+         i != fwd_decls.end(); ++i) {
       printer->Print("$value$;\n", "value", *i);
     }
-
-    if (dependencies.begin() != dependencies.end()) {
+    if (fwd_decls.begin() != fwd_decls.end()) {
       printer->Print("\n");
     }
   }
@@ -156,7 +167,14 @@ void FileGenerator::GenerateHeader(io::Printer *printer) {
         "#pragma mark - $root_class_name$\n"
         "\n"
         "@interface $root_class_name$ : GPBRootObject\n"
-        "@end\n\n",
+        "\n"
+        "// The base class provides:\n"
+        "//   + (GPBExtensionRegistry *)extensionRegistry;\n"
+        "// which is an GPBExtensionRegistry that includes all the extensions defined by\n"
+        "// this file and all files that it depends on.\n"
+        "\n"
+        "@end\n"
+        "\n",
         "root_class_name", root_class_name_);
   }
 
@@ -189,33 +207,10 @@ void FileGenerator::GenerateHeader(io::Printer *printer) {
   }
 
   printer->Print("CF_EXTERN_C_END\n");
-}
-
-void DetermineDependenciesWorker(set<string> *dependencies,
-                                 set<string> *seen_files,
-                                 const string &classname,
-                                 const FileDescriptor *file) {
-  if (seen_files->find(file->name()) != seen_files->end()) {
-    // don't infinitely recurse
-    return;
-  }
-
-  seen_files->insert(file->name());
-
-  for (int i = 0; i < file->dependency_count(); i++) {
-    DetermineDependenciesWorker(dependencies, seen_files, classname,
-                                file->dependency(i));
-  }
-  for (int i = 0; i < file->message_type_count(); i++) {
-    MessageGenerator(classname, file->message_type(i))
-        .DetermineDependencies(dependencies);
-  }
-}
 
-void FileGenerator::DetermineDependencies(set<string> *dependencies) {
-  set<string> seen_files;
-  DetermineDependenciesWorker(dependencies, &seen_files, root_class_name_,
-                              file_);
+  printer->Print(
+    "\n"
+    "// @@protoc_insertion_point(global_scope)\n");
 }
 
 void FileGenerator::GenerateSource(io::Printer *printer) {
@@ -225,6 +220,25 @@ void FileGenerator::GenerateSource(io::Printer *printer) {
       "\n",
       "filename", file_->name());
 
+  string header_file = Path() + ".pbobjc.h";
+  printer->Print(
+      "#import \"GPBProtocolBuffers_RuntimeSupport.h\"\n"
+      "#import \"$header_file$\"\n",
+      "header_file", header_file);
+  const vector<FileGenerator *> &dependency_generators =
+      DependencyGenerators();
+  for (vector<FileGenerator *>::const_iterator iter =
+           dependency_generators.begin();
+       iter != dependency_generators.end(); ++iter) {
+    if (!(*iter)->IsPublicDependency()) {
+      printer->Print("#import \"$header$.pbobjc.h\"\n",
+                     "header", (*iter)->Path());
+    }
+  }
+  printer->Print(
+      "// @@protoc_insertion_point(imports)\n"
+      "\n");
+
   if (IsFiltered()) {
     printer->Print(
         "// File empty because all messages, extensions and enum have been filtered.\n"
@@ -232,22 +246,17 @@ void FileGenerator::GenerateSource(io::Printer *printer) {
         "\n"
         "// Dummy symbol that will be stripped but will avoid linker warnings about\n"
         "// no symbols in the .o form compiling this file.\n"
-        "static int $root_class_name$_dummy __attribute__((unused,used)) = 0;\n",
+        "static int $root_class_name$_dummy __attribute__((unused,used)) = 0;\n"
+        "\n"
+        "// @@protoc_insertion_point(global_scope)\n",
         "root_class_name", root_class_name_);
     return;
   }
 
-  printer->Print("#import \"GPBProtocolBuffers_RuntimeSupport.h\"\n\n");
-
-  string header_file = Path() + ".pbobjc.h";
-
   printer->Print(
-      "#import \"$header_file$\"\n"
-      "\n"
       "#pragma mark - $root_class_name$\n"
       "\n"
       "@implementation $root_class_name$\n\n",
-      "header_file", header_file,
       "root_class_name", root_class_name_);
 
   bool generated_extensions = false;
@@ -326,12 +335,7 @@ void FileGenerator::GenerateSource(io::Printer *printer) {
           "  }\n"
           "  return registry;\n"
           "}\n"
-          "\n"
-          "+ (void)load {\n"
-          "  @autoreleasepool {\n"
-          "    [self extensionRegistry]; // Construct extension registry.\n"
-          "  }\n"
-          "}\n\n");
+          "\n");
     }
   }
 
@@ -374,19 +378,31 @@ void FileGenerator::GenerateSource(io::Printer *printer) {
        iter != message_generators_.end(); ++iter) {
     (*iter)->GenerateSource(printer);
   }
+
+  printer->Print(
+    "\n"
+    "// @@protoc_insertion_point(global_scope)\n");
 }
 
 const string FileGenerator::Path() const { return FilePath(file_); }
 
 const vector<FileGenerator *> &FileGenerator::DependencyGenerators() {
   if (file_->dependency_count() != dependency_generators_.size()) {
+    set<string> public_import_names;
+    for (int i = 0; i < file_->public_dependency_count(); i++) {
+      public_import_names.insert(file_->public_dependency(i)->name());
+    }
     for (int i = 0; i < file_->dependency_count(); i++) {
       FileGenerator *generator = new FileGenerator(file_->dependency(i));
+      const string& name = file_->dependency(i)->name();
+      bool public_import = (public_import_names.count(name) != 0);
+      generator->SetIsPublicDependency(public_import);
       dependency_generators_.push_back(generator);
     }
   }
   return dependency_generators_;
 }
+
 }  // namespace objectivec
 }  // namespace compiler
 }  // namespace protobuf
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_file.h b/src/google/protobuf/compiler/objectivec/objectivec_file.h
index fbd08eae..95d17bfd 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_file.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_file.h
@@ -66,6 +66,12 @@ class FileGenerator {
 
   bool IsFiltered() const { return is_filtered_; }
   bool AreAllExtensionsFiltered() const { return all_extensions_filtered_; }
+  bool IsPublicDependency() const { return is_public_dep_; }
+
+ protected:
+  void SetIsPublicDependency(bool is_public_dep) {
+    is_public_dep_ = is_public_dep;
+  }
 
  private:
   const FileDescriptor* file_;
@@ -80,15 +86,16 @@ class FileGenerator {
   vector<ExtensionGenerator*> extension_generators_;
   bool is_filtered_;
   bool all_extensions_filtered_;
-
-  void DetermineDependencies(set<string>* dependencies);
+  bool is_public_dep_;
 
   const vector<FileGenerator*>& DependencyGenerators();
 
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FileGenerator);
 };
+
 }  // namespace objectivec
 }  // namespace compiler
 }  // namespace protobuf
 }  // namespace google
+
 #endif  // GOOGLE_PROTOBUF_COMPILER_OBJECTIVEC_FILE_H__
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_helpers.cc b/src/google/protobuf/compiler/objectivec/objectivec_helpers.cc
index d4675f02..6d6e5959 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_helpers.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_helpers.cc
@@ -41,7 +41,7 @@
 #include <google/protobuf/stubs/strutil.h>
 
 // NOTE: src/google/protobuf/compiler/plugin.cc makes use of cerr for some
-// error case, so it seem to be ok to use as a back door for errors.
+// error cases, so it seems to be ok to use as a back door for errors.
 
 namespace google {
 namespace protobuf {
@@ -53,6 +53,11 @@ namespace {
 hash_set<string> gClassWhitelist;
 
 // islower()/isupper()/tolower()/toupper() change based on locale.
+//
+// src/google/protobuf/stubs/strutil.h:150 has the same pattern. For the
+// Objective C plugin, test failures were seen on TravisCI because isupper('A')
+// was coming back false for some server's locale.  This approach avoids any
+// such issues.
 
 bool IsLower(const char c) {
   return ('a' <= c && c <= 'z');
@@ -205,10 +210,9 @@ const char* const kReservedWordList[] = {
     // Only need to add instance methods that may conflict with
     // method declared in protos. The main cases are methods
     // that take no arguments, or setFoo:/hasFoo: type methods.
-    // These are currently in the same order as in GPBMessage.h.
-    "unknownFields", "extensionRegistry", "isInitialized",
-    "data", "delimitedData", "serializedSize",
-    "descriptor", "extensionsCurrentlySet", "clear", "sortedExtensionsInUse",
+    "clear", "data", "delimitedData", "descriptor", "extensionRegistry",
+    "extensionsCurrentlySet", "isInitialized", "serializedSize",
+    "sortedExtensionsInUse", "unknownFields",
 
     // MacTypes.h names
     "Fixed", "Fract", "Size", "LogicalAddress", "PhysicalAddress", "ByteCount",
@@ -335,7 +339,32 @@ string FilePath(const FileDescriptor* file) {
 
 string FileClassPrefix(const FileDescriptor* file) {
   // Default is empty string, no need to check has_objc_class_prefix.
-  return file->options().objc_class_prefix();
+  string result = file->options().objc_class_prefix();
+  return result;
+}
+
+void ValidateObjCClassPrefix(const FileDescriptor* file) {
+  string prefix = file->options().objc_class_prefix();
+  if (prefix.length() > 0) {
+    // NOTE: src/google/protobuf/compiler/plugin.cc makes use of cerr for some
+    // error cases, so it seems to be ok to use as a back door for errors.
+    if (!IsUpper(prefix[0])) {
+      cerr << endl
+           << "protoc:0: warning: Invalid 'option objc_class_prefix = \""
+           << prefix << "\";' in '" << file->name() << "';"
+           << " it should start with a capital letter."
+           << endl;
+      cerr.flush();
+    }
+    if (prefix.length() < 3) {
+      cerr << endl
+           << "protoc:0: warning: Invalid 'option objc_class_prefix = \""
+           << prefix << "\";' in '" << file->name() << "';"
+           << " Apple recommends they should be at least 3 characters long."
+           << endl;
+      cerr.flush();
+    }
+  }
 }
 
 string FileClassName(const FileDescriptor* file) {
@@ -468,7 +497,7 @@ string OneofEnumName(const OneofDescriptor* descriptor) {
   const Descriptor* fieldDescriptor = descriptor->containing_type();
   string name = ClassName(fieldDescriptor);
   name += "_" + UnderscoresToCamelCase(descriptor->name(), true) + "_OneOfCase";
-  // No sanitize needed because it the OS never has names that end in OneOfCase.
+  // No sanitize needed because the OS never has names that end in _OneOfCase.
   return name;
 }
 
@@ -560,6 +589,8 @@ string GetCapitalizedType(const FieldDescriptor* field) {
       return "Message";
   }
 
+  // Some compilers report reaching end of function even though all cases of
+  // the enum are handed in the switch.
   GOOGLE_LOG(FATAL) << "Can't get here.";
   return NULL;
 }
@@ -607,6 +638,8 @@ ObjectiveCType GetObjectiveCType(FieldDescriptor::Type field_type) {
       return OBJECTIVECTYPE_MESSAGE;
   }
 
+  // Some compilers report reaching end of function even though all cases of
+  // the enum are handed in the switch.
   GOOGLE_LOG(FATAL) << "Can't get here.";
   return OBJECTIVECTYPE_INT32;
 }
@@ -683,6 +716,8 @@ string GPBValueFieldName(const FieldDescriptor* field) {
       return "valueMessage";
   }
 
+  // Some compilers report reaching end of function even though all cases of
+  // the enum are handed in the switch.
   GOOGLE_LOG(FATAL) << "Can't get here.";
   return NULL;
 }
@@ -753,6 +788,8 @@ string DefaultValue(const FieldDescriptor* field) {
       return "nil";
   }
 
+  // Some compilers report reaching end of function even though all cases of
+  // the enum are handed in the switch.
   GOOGLE_LOG(FATAL) << "Can't get here.";
   return NULL;
 }
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_helpers.h b/src/google/protobuf/compiler/objectivec/objectivec_helpers.h
index ab030d15..29168937 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_helpers.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_helpers.h
@@ -62,6 +62,9 @@ string FileName(const FileDescriptor* file);
 // declared in the proto package.
 string FilePath(const FileDescriptor* file);
 
+// Checks the prefix for a given file and outputs any warnings/errors needed.
+void ValidateObjCClassPrefix(const FileDescriptor* file);
+
 // Gets the name of the root class we'll generate in the file.  This class
 // is not meant for external consumption, but instead contains helpers that
 // the rest of the the classes need
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_map_field.cc b/src/google/protobuf/compiler/objectivec/objectivec_map_field.cc
index cafdf39d..2987f3db 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_map_field.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_map_field.cc
@@ -76,6 +76,8 @@ const char* MapEntryTypeName(const FieldDescriptor* descriptor, bool isKey) {
       return "Object";
   }
 
+  // Some compilers report reaching end of function even though all cases of
+  // the enum are handed in the switch.
   GOOGLE_LOG(FATAL) << "Can't get here.";
   return NULL;
 }
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_map_field.h b/src/google/protobuf/compiler/objectivec/objectivec_map_field.h
index 8862dc35..173541f2 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_map_field.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_map_field.h
@@ -48,7 +48,7 @@ class MapFieldGenerator : public RepeatedFieldGenerator {
   virtual void GenerateFieldDescriptionTypeSpecific(io::Printer* printer) const;
 
  protected:
-  MapFieldGenerator(const FieldDescriptor* descriptor);
+  explicit MapFieldGenerator(const FieldDescriptor* descriptor);
   virtual ~MapFieldGenerator();
 
  private:
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_message.cc b/src/google/protobuf/compiler/objectivec/objectivec_message.cc
index f6a5852d..52e583bf 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_message.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_message.cc
@@ -120,6 +120,8 @@ int OrderGroupForFieldDescriptor(const FieldDescriptor* descriptor) {
       return 1;
   }
 
+  // Some compilers report reaching end of function even though all cases of
+  // the enum are handed in the switch.
   GOOGLE_LOG(FATAL) << "Can't get here.";
   return 0;
 }
@@ -188,7 +190,7 @@ MessageGenerator::MessageGenerator(const string& root_classname,
       extension_generators_.push_back(
           new ExtensionGenerator(class_name_, descriptor_->extension(i)));
     }
-    // No need to oneofs if this message is filtered
+    // No need to generate oneofs if this message is filtered.
     for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
       OneofGenerator* generator = new OneofGenerator(descriptor_->oneof_decl(i));
       oneof_generators_.push_back(generator);
@@ -253,15 +255,24 @@ void MessageGenerator::GenerateStaticVariablesInitialization(
   }
 }
 
-void MessageGenerator::DetermineDependencies(set<string>* dependencies) {
+void MessageGenerator::DetermineForwardDeclarations(set<string>* fwd_decls) {
   if (!IsFiltered() && !IsMapEntryMessage(descriptor_)) {
-    dependencies->insert("@class " + class_name_);
+    for (int i = 0; i < descriptor_->field_count(); i++) {
+      const FieldDescriptor* fieldDescriptor = descriptor_->field(i);
+      // If it is a the field is repeated, the type will be and *Array,
+      // and we don't need any forward decl.
+      if (fieldDescriptor->is_repeated()) {
+        continue;
+      }
+      field_generators_.get(fieldDescriptor)
+          .DetermineForwardDeclarations(fwd_decls);
+    }
   }
 
   for (vector<MessageGenerator*>::iterator iter =
            nested_message_generators_.begin();
        iter != nested_message_generators_.end(); ++iter) {
-    (*iter)->DetermineDependencies(dependencies);
+    (*iter)->DetermineForwardDeclarations(fwd_decls);
   }
 }
 
@@ -361,13 +372,13 @@ void MessageGenerator::GenerateMessageHeader(io::Printer* printer) {
         "classname", class_name_,
         "comments", message_comments);
 
-    vector<bool> seen_oneofs(descriptor_->oneof_decl_count(), false);
+    vector<char> seen_oneofs(descriptor_->oneof_decl_count(), 0);
     for (int i = 0; i < descriptor_->field_count(); i++) {
       const FieldDescriptor* field = descriptor_->field(i);
       if (field->containing_oneof() != NULL) {
         const int oneof_index = field->containing_oneof()->index();
         if (!seen_oneofs[oneof_index]) {
-          seen_oneofs[oneof_index] = true;
+          seen_oneofs[oneof_index] = 1;
           oneof_generators_[oneof_index]->GeneratePublicCasePropertyDeclaration(
               printer);
         }
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_message.h b/src/google/protobuf/compiler/objectivec/objectivec_message.h
index 5992d0cf..8d03c0b8 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_message.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_message.h
@@ -63,7 +63,7 @@ class MessageGenerator {
   void GenerateMessageHeader(io::Printer* printer);
   void GenerateSource(io::Printer* printer);
   void GenerateExtensionRegistrationSource(io::Printer* printer);
-  void DetermineDependencies(set<string>* dependencies);
+  void DetermineForwardDeclarations(set<string>* fwd_decls);
 
   // This only speaks for this message, not sub message/enums.
   bool IsFiltered() const { return filter_reason_.length() > 0; }
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_message_field.cc b/src/google/protobuf/compiler/objectivec/objectivec_message_field.cc
index 9c4a4e44..2e3bdfdb 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_message_field.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_message_field.cc
@@ -65,6 +65,12 @@ MessageFieldGenerator::MessageFieldGenerator(const FieldDescriptor* descriptor)
 
 MessageFieldGenerator::~MessageFieldGenerator() {}
 
+void MessageFieldGenerator::DetermineForwardDeclarations(
+    set<string>* fwd_decls) const {
+  // Class name is already in "storage_type".
+  fwd_decls->insert("@class " + variable("storage_type"));
+}
+
 bool MessageFieldGenerator::WantsHasProperty(void) const {
   if (descriptor_->containing_oneof() != NULL) {
     // If in a oneof, it uses the oneofcase instead of a has bit.
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_message_field.h b/src/google/protobuf/compiler/objectivec/objectivec_message_field.h
index a1ac2d39..708ea566 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_message_field.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_message_field.h
@@ -44,10 +44,13 @@ class MessageFieldGenerator : public ObjCObjFieldGenerator {
   friend FieldGenerator* FieldGenerator::Make(const FieldDescriptor* field);
 
  protected:
-  MessageFieldGenerator(const FieldDescriptor* descriptor);
+  explicit MessageFieldGenerator(const FieldDescriptor* descriptor);
   virtual ~MessageFieldGenerator();
   virtual bool WantsHasProperty(void) const;
 
+ public:
+  virtual void DetermineForwardDeclarations(set<string>* fwd_decls) const;
+
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MessageFieldGenerator);
 };
@@ -56,7 +59,7 @@ class RepeatedMessageFieldGenerator : public RepeatedFieldGenerator {
   friend FieldGenerator* FieldGenerator::Make(const FieldDescriptor* field);
 
  protected:
-  RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor);
+  explicit RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor);
   virtual ~RepeatedMessageFieldGenerator();
 
  private:
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_oneof.h b/src/google/protobuf/compiler/objectivec/objectivec_oneof.h
index 77b7f800..bcba82da 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_oneof.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_oneof.h
@@ -49,7 +49,7 @@ namespace objectivec {
 
 class OneofGenerator {
  public:
-  OneofGenerator(const OneofDescriptor* descriptor);
+  explicit OneofGenerator(const OneofDescriptor* descriptor);
   ~OneofGenerator();
 
   void SetOneofIndexBase(int index_base);
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_primitive_field.cc b/src/google/protobuf/compiler/objectivec/objectivec_primitive_field.cc
index 54f94284..c185b66d 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_primitive_field.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_primitive_field.cc
@@ -77,6 +77,8 @@ const char* PrimitiveTypeName(const FieldDescriptor* descriptor) {
       return NULL;
   }
 
+  // Some compilers report reaching end of function even though all cases of
+  // the enum are handed in the switch.
   GOOGLE_LOG(FATAL) << "Can't get here.";
   return NULL;
 }
@@ -108,6 +110,8 @@ const char* PrimitiveArrayTypeName(const FieldDescriptor* descriptor) {
       return "";  // Want NSArray
   }
 
+  // Some compilers report reaching end of function even though all cases of
+  // the enum are handed in the switch.
   GOOGLE_LOG(FATAL) << "Can't get here.";
   return NULL;
 }
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_primitive_field.h b/src/google/protobuf/compiler/objectivec/objectivec_primitive_field.h
index b3599297..9bb79343 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_primitive_field.h
+++ b/src/google/protobuf/compiler/objectivec/objectivec_primitive_field.h
@@ -44,7 +44,7 @@ class PrimitiveFieldGenerator : public SingleFieldGenerator {
   friend FieldGenerator* FieldGenerator::Make(const FieldDescriptor* field);
 
  protected:
-  PrimitiveFieldGenerator(const FieldDescriptor* descriptor);
+  explicit PrimitiveFieldGenerator(const FieldDescriptor* descriptor);
   virtual ~PrimitiveFieldGenerator();
 
  private:
@@ -55,7 +55,7 @@ class PrimitiveObjFieldGenerator : public ObjCObjFieldGenerator {
   friend FieldGenerator* FieldGenerator::Make(const FieldDescriptor* field);
 
  protected:
-  PrimitiveObjFieldGenerator(const FieldDescriptor* descriptor);
+  explicit PrimitiveObjFieldGenerator(const FieldDescriptor* descriptor);
   virtual ~PrimitiveObjFieldGenerator();
 
  private:
@@ -66,7 +66,7 @@ class RepeatedPrimitiveFieldGenerator : public RepeatedFieldGenerator {
   friend FieldGenerator* FieldGenerator::Make(const FieldDescriptor* field);
 
  protected:
-  RepeatedPrimitiveFieldGenerator(const FieldDescriptor* descriptor);
+  explicit RepeatedPrimitiveFieldGenerator(const FieldDescriptor* descriptor);
   virtual ~RepeatedPrimitiveFieldGenerator();
   virtual void FinishInitialization(void);