First stab at new proto3-only code generator

1 files changed, 153 insertions, 702 deletions

diff --git a/src/google/protobuf/compiler/csharp/csharp_message.cc b/src/google/protobuf/compiler/csharp/csharp_message.cc
index 66b87110..1defcf94 100644
--- a/src/google/protobuf/compiler/csharp/csharp_message.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_message.cc
@@ -43,7 +43,6 @@
 #include <google/protobuf/wire_format_lite.h>
 
 #include <google/protobuf/compiler/csharp/csharp_enum.h>
-#include <google/protobuf/compiler/csharp/csharp_extension.h>
 #include <google/protobuf/compiler/csharp/csharp_message.h>
 #include <google/protobuf/compiler/csharp/csharp_helpers.h>
 #include <google/protobuf/compiler/csharp/csharp_field_base.h>
@@ -106,7 +105,7 @@ std::string GetUniqueFileScopeIdentifier(const Descriptor* descriptor) {
 }
 
 void MessageGenerator::GenerateStaticVariables(io::Printer* printer) {
-  // Because descriptor.proto (Google.ProtocolBuffers.DescriptorProtos) is
+  // Because descriptor.proto (Google.Protobuf.DescriptorProtos) is
   // used in the construction of descriptors, we have a tricky bootstrapping
   // problem.  To help control static initialization order, we make sure all
   // descriptors and other static data that depends on them are members of
@@ -115,14 +114,12 @@ void MessageGenerator::GenerateStaticVariables(io::Printer* printer) {
 
   std::string identifier = GetUniqueFileScopeIdentifier(descriptor_);
 
-  if (!use_lite_runtime()) {
-    // The descriptor for this type.
-    printer->Print(
-        "internal static pbd::MessageDescriptor internal__$identifier$__Descriptor;\n"
-        "internal static pb::FieldAccess.FieldAccessorTable<$full_class_name$, $full_class_name$.Builder> internal__$identifier$__FieldAccessorTable;\n",
-	"identifier", GetUniqueFileScopeIdentifier(descriptor_),
-	"full_class_name", full_class_name());
-  }
+  // The descriptor for this type.
+  printer->Print(
+      "internal static pbd::MessageDescriptor internal__$identifier$__Descriptor;\n"
+      "internal static pb::FieldAccess.FieldAccessorTable<$full_class_name$> internal__$identifier$__FieldAccessorTable;\n",
+      "identifier", GetUniqueFileScopeIdentifier(descriptor_),
+      "full_class_name", full_class_name());
 
   for (int i = 0; i < descriptor_->nested_type_count(); i++) {
     MessageGenerator messageGenerator(descriptor_->nested_type(i));
@@ -139,139 +136,106 @@ void MessageGenerator::GenerateStaticVariableInitializers(io::Printer* printer)
     vars["parent"] = GetUniqueFileScopeIdentifier(
 	descriptor_->containing_type());
   }
-  if (!use_lite_runtime()) {
-    printer->Print(vars, "internal__$identifier$__Descriptor = ");
+  printer->Print(vars, "internal__$identifier$__Descriptor = ");
 
-    if (!descriptor_->containing_type()) {
-      printer->Print(vars, "Descriptor.MessageTypes[$index$];\n");
-    } else {
-      printer->Print(vars, "internal__$parent$__Descriptor.NestedTypes[$index$];\n");
-    }
+  if (!descriptor_->containing_type()) {
+    printer->Print(vars, "Descriptor.MessageTypes[$index$];\n");
+  } else {
+    printer->Print(vars, "internal__$parent$__Descriptor.NestedTypes[$index$];\n");
+  }
 
-    printer->Print(
-      vars,
-      "internal__$identifier$__FieldAccessorTable = \n"
-      "    new pb::FieldAccess.FieldAccessorTable<$full_class_name$, $full_class_name$.Builder>(internal__$identifier$__Descriptor,\n");
-    printer->Print("        new string[] { ");
-    for (int i = 0; i < descriptor_->field_count(); i++) {
-      printer->Print("\"$property_name$\", ",
-                     "property_name", GetPropertyName(descriptor_->field(i)));
-    }
-    for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
-      printer->Print("\"$oneof_name$\", ",
-                     "oneof_name",
-                     UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true));
-    }
-    printer->Print("});\n");
+  printer->Print(
+    vars,
+    "internal__$identifier$__FieldAccessorTable = \n"
+    "    new pb::FieldAccess.FieldAccessorTable<$full_class_name$>(internal__$identifier$__Descriptor,\n");
+  printer->Print("        new string[] { ");
+  for (int i = 0; i < descriptor_->field_count(); i++) {
+    printer->Print("\"$property_name$\", ",
+                   "property_name", GetPropertyName(descriptor_->field(i)));
+  }
+  for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
+    printer->Print("\"$oneof_name$\", ",
+                   "oneof_name",
+                   UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true));
   }
+  printer->Print("});\n");
 
   // Generate static member initializers for all nested types.
   for (int i = 0; i < descriptor_->nested_type_count(); i++) {
     MessageGenerator messageGenerator(descriptor_->nested_type(i));
     messageGenerator.GenerateStaticVariableInitializers(printer);
   }
-
-  for (int i = 0; i < descriptor_->extension_count(); i++) {
-    ExtensionGenerator extensionGenerator(descriptor_->extension(i));
-    extensionGenerator.GenerateStaticVariableInitializers(printer);
-  }
 }
 
 void MessageGenerator::Generate(io::Printer* printer) {
   map<string, string> vars;
   vars["class_name"] = class_name();
   vars["access_level"] = class_access_level();
-  vars["extendable_or_generated"] = descriptor_->extension_range_count() > 0 ?
-    "Extendable" : "Generated";
-  vars["suffix"] = runtime_suffix();
   vars["umbrella_class_name"] = GetFullUmbrellaClassName(descriptor_->file());
   vars["identifier"] = GetUniqueFileScopeIdentifier(descriptor_);
 
   printer->Print(
-      "[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]\n");
+    "[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]\n");
   WriteGeneratedCodeAttributes(printer);
   printer->Print(
     vars,
-    "$access_level$ sealed partial class $class_name$ : pb::$extendable_or_generated$Message$suffix$<$class_name$, $class_name$.Builder> {\n");
+    "$access_level$ sealed partial class $class_name$ : pb::IMessage<$class_name$> {\n");
   printer->Indent();
-  printer->Print(
-    vars,
-    "private $class_name$() { }\n"  // Private ctor.
-    // Must call MakeReadOnly() to make sure all lists are made read-only
-    "private static readonly $class_name$ defaultInstance = new $class_name$().MakeReadOnly();\n");
 
-  if (optimize_speed()) {
-    printer->Print(
-      "private static readonly string[] _$name$FieldNames = "
-      "new string[] { $slash$$field_names$$slash$ };\n",
-      "name", UnderscoresToCamelCase(class_name(), false),
-      "field_names", JoinStrings(field_names(), "\", \""),
+  // All static fields and properties
+  printer->Print(
+    "private static readonly string[] _fieldNames = "
+    "new string[] { $slash$$field_names$$slash$ };\n",
+    "field_names", JoinStrings(field_names(), "\", \""),
       "slash", field_names().size() > 0 ? "\"" : "");
-    std::vector<std::string> tags;
-    for (int i = 0; i < field_names().size(); i++) {
-      uint32 tag = internal::WireFormat::MakeTag(
-          descriptor_->FindFieldByName(field_names()[i]));
-      tags.push_back(SimpleItoa(tag));
-    }
-    printer->Print(
-      "private static readonly uint[] _$name$FieldTags = new uint[] { $tags$ };\n",
-      "name", UnderscoresToCamelCase(class_name(), false),
-      "tags", JoinStrings(tags, ", "));
+  std::vector<std::string> tags;
+  for (int i = 0; i < field_names().size(); i++) {
+    uint32 tag = internal::WireFormat::MakeTag(
+        descriptor_->FindFieldByName(field_names()[i]));
+    tags.push_back(SimpleItoa(tag));
   }
   printer->Print(
+    "private static readonly uint[] _fieldTags = new uint[] { $tags$ };\n",
+    "tags", JoinStrings(tags, ", "));
+
+  printer->Print(
     vars,
-    "public static $class_name$ DefaultInstance {\n"
-    "  get { return defaultInstance; }\n"
+    "public static pbd::MessageDescriptor Descriptor {\n"
+    "  get { return $umbrella_class_name$.internal__$identifier$__Descriptor; }\n"
     "}\n"
     "\n"
-    "public override $class_name$ DefaultInstanceForType {\n"
-    "  get { return DefaultInstance; }\n"
+    "protected override pb::FieldAccess.FieldAccessorTable<$class_name$> InternalFieldAccessors {\n"
+    "  get { return $umbrella_class_name$.internal__$identifier$__FieldAccessorTable; }\n"
     "}\n"
-    "\n"
-    "protected override $class_name$ ThisMessage {\n"
-    "  get { return this; }\n"
-    "}\n\n");
+    "\n");
 
-  if (!use_lite_runtime()) {
-    printer->Print(
-      vars,
-      "public static pbd::MessageDescriptor Descriptor {\n"
-      "  get { return $umbrella_class_name$.internal__$identifier$__Descriptor; }\n"
-      "}\n"
-      "\n"
-      "protected override pb::FieldAccess.FieldAccessorTable<$class_name$, $class_name$.Builder> InternalFieldAccessors {\n"
-      "  get { return $umbrella_class_name$.internal__$identifier$__FieldAccessorTable; }\n"
-      "}\n"
-      "\n");
-  }
+  // Constructors
+  printer->Print(
+    vars,
+    "public $class_name$() { }\n");  // Public parameterless ctor.
 
-  // Extensions don't need to go in an extra nested type
-  for (int i = 0; i < descriptor_->extension_count(); i++) {
-    ExtensionGenerator extensionGenerator(descriptor_->extension(i));
-    extensionGenerator.Generate(printer);
-  }
+  printer->Print(
+    vars,
+    "public $class_name$($class_name$ other) {\n"
+    "  MergeWith(other);\n"
+    "}\n");  // Merge ctor.
 
-  if (descriptor_->enum_type_count() + descriptor_->nested_type_count() > 0) {
-    printer->Print("#region Nested types\n"
-		   "[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]\n");
-    WriteGeneratedCodeAttributes(printer);
-    printer->Print("public static partial class Types {\n");
-    printer->Indent();
-    for (int i = 0; i < descriptor_->enum_type_count(); i++) {
-      EnumGenerator enumGenerator(descriptor_->enum_type(i));
-      enumGenerator.Generate(printer);
-    }
-    for (int i = 0; i < descriptor_->nested_type_count(); i++) {
-      MessageGenerator messageGenerator(descriptor_->nested_type(i));
-      messageGenerator.Generate(printer);
-    }
-    printer->Outdent();
-    printer->Print("}\n"
-                   "#endregion\n"
-                   "\n");
+  // Fields/properties
+  for (int i = 0; i < descriptor_->field_count(); i++) {
+    const FieldDescriptor* fieldDescriptor = descriptor_->field(i);
+
+    // Rats: we lose the debug comment here :(
+    printer->Print(
+      "public const int $field_constant_name$ = $index$;\n",
+      "field_constant_name", GetFieldConstantName(fieldDescriptor),
+      "index", SimpleItoa(fieldDescriptor->number()));
+    scoped_ptr<FieldGeneratorBase> generator(
+        CreateFieldGeneratorInternal(fieldDescriptor));
+    generator->GenerateMembers(printer);
+    printer->Print("\n");
   }
 
-  // oneof
+  // oneof properties
   for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
     vars["name"] = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), false);
     vars["property_name"] = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true);
@@ -280,13 +244,13 @@ void MessageGenerator::Generate(io::Printer* printer) {
       "private object $name$_;\n"
       "public enum $property_name$OneofCase {\n");
     printer->Indent();
+    printer->Print("None = 0,\n");
     for (int j = 0; j < descriptor_->oneof_decl(i)->field_count(); j++) {
       const FieldDescriptor* field = descriptor_->oneof_decl(i)->field(j);
       printer->Print("$field_property_name$ = $index$,\n",
                      "field_property_name", GetPropertyName(field),
                      "index", SimpleItoa(field->number()));
     }
-    printer->Print("None = 0,\n");
     printer->Outdent();
     printer->Print("}\n");
     printer->Print(
@@ -294,243 +258,78 @@ void MessageGenerator::Generate(io::Printer* printer) {
       "private $property_name$OneofCase $name$Case_ = $property_name$OneofCase.None;\n"
       "public $property_name$OneofCase $property_name$Case {\n"
       "  get { return $name$Case_; }\n"
+      "}\n\n"
+      "private Clear$property_name$() {;\n"
+      "  $name$Case_ = $property_name$OneofCase.None;"
+      "  $name$_ = null;"
       "}\n\n");
   }
 
-  // Fields
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    const FieldDescriptor* fieldDescriptor = descriptor_->field(i);
+  // TODO(jonskeet): Map properties
 
-    // Rats: we lose the debug comment here :(
-    printer->Print(
-      "public const int $field_constant_name$ = $index$;\n",
-      "field_constant_name", GetFieldConstantName(fieldDescriptor),
-      "index", SimpleItoa(fieldDescriptor->number()));
-    scoped_ptr<FieldGeneratorBase> generator(
-        CreateFieldGeneratorInternal(fieldDescriptor));
-    generator->GenerateMembers(printer);
-    printer->Print("\n");
-  }
+  // Standard methods
+  GenerateMessageSerializationMethods(printer);
+  GenerateMergingMethods(printer);
 
-  if (optimize_speed()) {
-    if (SupportFieldPresence(descriptor_->file())) {
-      GenerateIsInitialized(printer);
+  // Nested messages and enums
+  if (descriptor_->enum_type_count() + descriptor_->nested_type_count() > 0) {
+    printer->Print("#region Nested types\n"
+		   "[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]\n");
+    WriteGeneratedCodeAttributes(printer);
+    printer->Print("public static partial class Types {\n");
+    printer->Indent();
+    for (int i = 0; i < descriptor_->enum_type_count(); i++) {
+      EnumGenerator enumGenerator(descriptor_->enum_type(i));
+      enumGenerator.Generate(printer);
     }
-    GenerateMessageSerializationMethods(printer);
-  }
-  if (use_lite_runtime()) {
-    GenerateLiteRuntimeMethods(printer);
-  }
-
-  GenerateParseFromMethods(printer);
-  GenerateBuilder(printer);
-
-  // Force the static initialization code for the file to run, since it may
-  // initialize static variables declared in this class.
-  printer->Print(vars, "static $class_name$() {\n");
-  // We call object.ReferenceEquals() just to make it a valid statement on its own.
-  // Another option would be GetType(), but that causes problems in DescriptorProtoFile,
-  // where the bootstrapping is somewhat recursive - type initializers call
-  // each other, effectively. We temporarily see Descriptor as null.
-  printer->Print(
-    vars,
-    "  object.ReferenceEquals($umbrella_class_name$.Descriptor, null);\n"
-    "}\n");
-
-  printer->Outdent();
-  printer->Print("}\n");
-  printer->Print("\n");
-
-}
-
-void MessageGenerator::GenerateLiteRuntimeMethods(io::Printer* printer) {
-  map<string, string> vars;
-  vars["class_name"] = class_name();
-
-  bool callbase = descriptor_->extension_range_count() > 0;
-  printer->Print("#region Lite runtime methods\n"
-                 "public override int GetHashCode() {\n");
-  printer->Indent();
-  printer->Print("int hash = GetType().GetHashCode();\n");
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    const FieldDescriptor* field = descriptor_->field(i);
-    if (field->containing_oneof() == NULL) {
-      scoped_ptr<FieldGeneratorBase> generator(
-          CreateFieldGeneratorInternal(field));
-      generator->WriteHash(printer);
+    for (int i = 0; i < descriptor_->nested_type_count(); i++) {
+      MessageGenerator messageGenerator(descriptor_->nested_type(i));
+      messageGenerator.Generate(printer);
     }
-  }
-  for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
-    string name = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), false);
-    string property_name = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true);
-    printer->Print(
-      "if ($name$Case_ != $property_name$OneofCase.None) {\n"
-      "  hash ^= $name$_.GetHashCode();\n"
-      "}\n",
-      "name", UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), false),
-      "property_name",
-      UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true));
-  }
-  if (callbase) {
-    printer->Print("hash ^= base.GetHashCode();\n");
-  }
-  printer->Print("return hash;\n");
-  printer->Outdent();
-  printer->Print("}\n");
-  printer->Print("\n");
-
-  printer->Print("public override bool Equals(object obj) {\n");
-  printer->Indent();
-  printer->Print(
-    vars,
-    "$class_name$ other = obj as $class_name$;\n"
-    "if (other == null) return false;\n");
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    scoped_ptr<FieldGeneratorBase> generator(
-        CreateFieldGeneratorInternal(descriptor_->field(i)));
-    generator->WriteEquals(printer);
-  }
-  if (callbase) {
-    printer->Print("if (!base.Equals(other)) return false;\n");
-  }
-  printer->Print("return true;\n");
-  printer->Outdent();
-  printer->Print("}\n");
-  printer->Print("\n");
-
-  printer->Print(
-    "public override void PrintTo(global::System.IO.TextWriter writer) {\n");
-  printer->Indent();
-
-  for (int i = 0; i < fields_by_number().size(); i++) {
-    scoped_ptr<FieldGeneratorBase> generator(
-        CreateFieldGeneratorInternal(fields_by_number()[i]));
-    generator->WriteToString(printer);
+    printer->Outdent();
+    printer->Print("}\n"
+                   "#endregion\n"
+                   "\n");
   }
 
-  if (callbase) {
-    printer->Print("base.PrintTo(writer);\n");
-  }
   printer->Outdent();
   printer->Print("}\n");
-  printer->Print("#endregion\n");
   printer->Print("\n");
-}
 
-bool CompareExtensionRangesStart(const Descriptor::ExtensionRange* r1,
-                                 const Descriptor::ExtensionRange* r2) {
-  return r1->start < r2->start;
 }
 
 void MessageGenerator::GenerateMessageSerializationMethods(io::Printer* printer) {
-  std::vector<const Descriptor::ExtensionRange*> extension_ranges_sorted;
-  for (int i = 0; i < descriptor_->extension_range_count(); i++) {
-    extension_ranges_sorted.push_back(descriptor_->extension_range(i));
-  }
-  std::sort(extension_ranges_sorted.begin(), extension_ranges_sorted.end(),
-            CompareExtensionRangesStart);
-
   printer->Print(
-      "public override void WriteTo(pb::ICodedOutputStream output) {\n");
+      "public void WriteTo(pb::ICodedOutputStream output) {\n");
   printer->Indent();
-  // Make sure we've computed the serialized length, so that packed fields are generated correctly.
-  printer->Print("CalcSerializedSize();\n"
-		 "string[] field_names = _$class_name$FieldNames;\n",
-                 "class_name", UnderscoresToCamelCase(class_name(), false));
-  if (descriptor_->extension_range_count()) {
-    printer->Print(
-      "pb::ExtendableMessage$runtime_suffix$<$class_name$, $class_name$.Builder>.ExtensionWriter extensionWriter = CreateExtensionWriter(this);\n",
-      "class_name", class_name(),
-      "runtime_suffix", runtime_suffix());
-  }
-
-  // Merge the fields and the extension ranges, both sorted by field number.
-  for (int i = 0, j = 0;
-      i < fields_by_number().size() || j < extension_ranges_sorted.size();) {
-    if (i == fields_by_number().size()) {
-      GenerateSerializeOneExtensionRange(printer, extension_ranges_sorted[j++]);
-    } else if (j == extension_ranges_sorted.size()) {
-      GenerateSerializeOneField(printer, fields_by_number()[i++]);
-    } else if (fields_by_number()[i]->number()
-        < extension_ranges_sorted[j]->start) {
-      GenerateSerializeOneField(printer, fields_by_number()[i++]);
-    } else {
-      GenerateSerializeOneExtensionRange(printer, extension_ranges_sorted[j++]);
-    }
-  }
+  printer->Print("string[] fieldNames = _fieldNames;\n");
 
-  if (!use_lite_runtime()) {
-    if (descriptor_->options().message_set_wire_format())
-    {
-      printer->Print("UnknownFields.WriteAsMessageSetTo(output);\n");
-    } else {
-      printer->Print("UnknownFields.WriteTo(output);\n");
-    }
+  // Serialize all the fields
+  for (int i = 0; i < fields_by_number().size(); i++) {
+    scoped_ptr<FieldGeneratorBase> generator(
+      CreateFieldGeneratorInternal(fields_by_number()[i]));
+    generator->GenerateSerializationCode(printer);
   }
 
+  // TODO(jonskeet): Memoize size of frozen messages?
   printer->Outdent();
   printer->Print(
     "}\n"
     "\n"
-    "private int memoizedSerializedSize = -1;\n"
-    "public override int SerializedSize {\n");
+    "public int CalculateSerializedSize() {\n");
   printer->Indent();
-  printer->Print("get {\n");
-  printer->Indent();
-  printer->Print(
-    "int size = memoizedSerializedSize;\n"
-    "if (size != -1) return size;\n"
-    "return CalcSerializedSize();\n");
-  printer->Outdent();
-  printer->Print("}\n");
-  printer->Outdent();
-  printer->Print("}\n");
-  printer->Print("\n");
-
-  printer->Print("private int CalcSerializedSize() {\n");
-  printer->Indent();
-  printer->Print(
-    "int size = memoizedSerializedSize;\n"
-    "if (size != -1) return size;\n"
-    "\n"
-    "size = 0;\n");
+  printer->Print("int size = 0;\n");
   for (int i = 0; i < descriptor_->field_count(); i++) {
     scoped_ptr<FieldGeneratorBase> generator(
         CreateFieldGeneratorInternal(descriptor_->field(i)));
     generator->GenerateSerializedSizeCode(printer);
   }
-  if (descriptor_->extension_range_count() > 0) {
-    printer->Print("size += ExtensionsSerializedSize;\n");
-  }
-
-  if (!use_lite_runtime()) {
-    if (descriptor_->options().message_set_wire_format()) {
-      printer->Print("size += UnknownFields.SerializedSizeAsMessageSet;\n");
-    } else {
-      printer->Print("size += UnknownFields.SerializedSize;\n");
-    }
-  }
-  printer->Print(
-    "memoizedSerializedSize = size;\n"
-    "return size;\n");
+  printer->Print("return size;\n");
   printer->Outdent();
   printer->Print("}\n");
 }
 
-void MessageGenerator::GenerateSerializeOneField(
-    io::Printer* printer, const FieldDescriptor* fieldDescriptor) {
-  scoped_ptr<FieldGeneratorBase> generator(
-      CreateFieldGeneratorInternal(fieldDescriptor));
-  generator->GenerateSerializationCode(printer);
-}
-
-void MessageGenerator::GenerateSerializeOneExtensionRange(
-    io::Printer* printer, const Descriptor::ExtensionRange* extensionRange) {
-  printer->Print("extensionWriter.WriteUntil($range_end$, output);\n",
-		 "range_end", SimpleItoa(extensionRange->end));
-}
-
-void MessageGenerator::GenerateParseFromMethods(io::Printer* printer) {
+void MessageGenerator::GenerateMergingMethods(io::Printer* printer) {
   // Note:  These are separate from GenerateMessageSerializationMethods()
   //   because they need to be generated even for messages that are optimized
   //   for code size.
@@ -539,339 +338,72 @@ void MessageGenerator::GenerateParseFromMethods(io::Printer* printer) {
 
   printer->Print(
     vars,
-    "public static $class_name$ ParseFrom(pb::ByteString data) {\n"
-    "  return ((Builder) CreateBuilder().MergeFrom(data)).BuildParsed();\n"
-    "}\n"
-    "public static $class_name$ ParseFrom(pb::ByteString data, pb::ExtensionRegistry extensionRegistry) {\n"
-    "  return ((Builder) CreateBuilder().MergeFrom(data, extensionRegistry)).BuildParsed();\n"
-    "}\n"
-    "public static $class_name$ ParseFrom(byte[] data) {\n"
-    "  return ((Builder) CreateBuilder().MergeFrom(data)).BuildParsed();\n"
-    "}\n"
-    "public static $class_name$ ParseFrom(byte[] data, pb::ExtensionRegistry extensionRegistry) {\n"
-    "  return ((Builder) CreateBuilder().MergeFrom(data, extensionRegistry)).BuildParsed();\n"
-    "}\n"
-    "public static $class_name$ ParseFrom(global::System.IO.Stream input) {\n"
-    "  return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();\n"
-    "}\n"
-    "public static $class_name$ ParseFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {\n"
-    "  return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();\n"
-    "}\n"
-    "public static $class_name$ ParseDelimitedFrom(global::System.IO.Stream input) {\n"
-    "  return CreateBuilder().MergeDelimitedFrom(input).BuildParsed();\n"
-    "}\n"
-    "public static $class_name$ ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {\n"
-    "  return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();\n"
-    "}\n"
-    "public static $class_name$ ParseFrom(pb::ICodedInputStream input) {\n"
-    "  return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();\n"
-    "}\n"
-    "public static $class_name$ ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {\n"
-    "  return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();\n"
-    "}\n");
-}
-
-void MessageGenerator::GenerateBuilder(io::Printer* printer) {
-  map<string, string> vars;
-  vars["class_name"] = class_name();
-  vars["access_level"] = class_access_level();
-  vars["extendable_or_generated"] = descriptor_->extension_range_count() > 0 ?
-    "Extendable" : "Generated";
-  vars["suffix"] = runtime_suffix();
-
-  printer->Print(vars, "private $class_name$ MakeReadOnly() {\n");
-  printer->Indent();
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    scoped_ptr<FieldGeneratorBase> generator(
-        CreateFieldGeneratorInternal(descriptor_->field(i)));
-    generator->GenerateBuildingCode(printer);
-  }
-  printer->Print("return this;\n");
-  printer->Outdent();
-  printer->Print("}\n\n");
-
-  printer->Print(
-    vars,
-    "public static Builder CreateBuilder() { return new Builder(); }\n"
-    "public override Builder ToBuilder() { return CreateBuilder(this); }\n"
-    "public override Builder CreateBuilderForType() { return new Builder(); }\n"
-    "public static Builder CreateBuilder($class_name$ prototype) {\n"
-    "  return new Builder(prototype);\n"
-    "}\n"
-    "\n"
-    "[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]\n");
-  WriteGeneratedCodeAttributes(printer);
-  printer->Print(
-    vars,
-    "$access_level$ sealed partial class Builder : pb::$extendable_or_generated$Builder$suffix$<$class_name$, Builder> {\n");
+    "public void MergeWith($class_name$ other) {\n");
   printer->Indent();
   printer->Print(
-    "protected override Builder ThisBuilder {\n"
-    "  get { return this; }\n"
+    "if (other == null) {\n"
+    "  return;\n"
     "}\n");
-  GenerateCommonBuilderMethods(printer);
-  if (optimize_speed()) {
-    GenerateBuilderParsingMethods(printer);
-  }
+  // TODO(jonskeet): Maps?
+  // Merge non-oneof fields
   for (int i = 0; i < descriptor_->field_count(); i++) {
-    scoped_ptr<FieldGeneratorBase> generator(
-        CreateFieldGeneratorInternal(descriptor_->field(i)));
-    printer->Print("\n");
-    // No field comment :(
-    generator->GenerateBuilderMembers(printer);
-  }
-
-  // oneof
-  for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
-    printer->Print("\n");
-    string name = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), false);
-    string property_name = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true);
-    printer->Print(
-      "public $property_name$OneofCase $property_name$Case {\n"
-      "  get { return result.$name$Case_; }\n"
-      "}\n"
-      "public Builder Clear$property_name$() {\n"
-      "  PrepareBuilder();\n"
-      "  result.$name$_ = null;\n"
-      "  result.$name$Case_ = $property_name$OneofCase.None;\n"
-      "  return this;\n"
-      "}\n",
-      "name", UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), false),
-      "property_name",
-      UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true));
-  }
-
-  printer->Outdent();
-  printer->Print("}\n");
-}
-
-void MessageGenerator::GenerateCommonBuilderMethods(io::Printer* printer) {
-  map<string, string> vars;
-  vars["class_name"] = class_name();
-  vars["full_class_name"] = full_class_name();
-  vars["suffix"] = runtime_suffix();
-
-  printer->Print(
-    vars,
-    //default constructor
-    "public Builder() {\n"
-    //Durring static initialization of message, DefaultInstance is expected to return null.
-    "  result = DefaultInstance;\n"
-    "  resultIsReadOnly = true;\n"
-    "}\n"
-    //clone constructor
-    "internal Builder($class_name$ cloneFrom) {\n"
-    "  result = cloneFrom;\n"
-    "  resultIsReadOnly = true;\n"
-    "}\n"
-    "\n"
-    "private bool resultIsReadOnly;\n"
-    "private $class_name$ result;\n"
-    "\n"
-    "private $class_name$ PrepareBuilder() {\n"
-    "  if (resultIsReadOnly) {\n"
-    "    $class_name$ original = result;\n"
-    "    result = new $class_name$();\n"
-    "    resultIsReadOnly = false;\n"
-    "    MergeFrom(original);\n"
-    "  }\n"
-    "  return result;\n"
-    "}\n"
-    "\n"
-    "public override bool IsInitialized {\n"
-    "  get { return result.IsInitialized; }\n"
-    "}\n"
-    "\n"
-    "protected override $class_name$ MessageBeingBuilt {\n"
-    "  get { return PrepareBuilder(); }\n"
-    "}\n"
-    "\n");
-  //Not actually expecting that DefaultInstance would ever be null here; however, we will ensure it does not break
-  printer->Print(
-    "public override Builder Clear() {\n"
-    "  result = DefaultInstance;\n"
-    "  resultIsReadOnly = true;\n"
-    "  return this;\n"
-    "}\n"
-    "\n"
-    "public override Builder Clone() {\n"
-    "  if (resultIsReadOnly) {\n"
-    "    return new Builder(result);\n"
-    "  } else {\n"
-    "    return new Builder().MergeFrom(result);\n"
-    "  }\n"
-    "}\n"
-    "\n");
-  if (!use_lite_runtime()) {
-    printer->Print(
-      vars,
-      "public override pbd::MessageDescriptor DescriptorForType {\n"
-      "  get { return $full_class_name$.Descriptor; }\n"
-      "}\n\n");
+    if (!descriptor_->field(i)->containing_oneof()) {      
+      scoped_ptr<FieldGeneratorBase> generator(
+          CreateFieldGeneratorInternal(descriptor_->field(i)));
+      generator->GenerateMergingCode(printer);
+    }
   }
-  printer->Print(
-    vars,
-    "public override $class_name$ DefaultInstanceForType {\n"
-    "  get { return $full_class_name$.DefaultInstance; }\n"
-    "}\n\n");
-
-  printer->Print(
-    vars,
-    "public override $class_name$ BuildPartial() {\n"
-    "  if (resultIsReadOnly) {\n"
-    "    return result;\n"
-    "  }\n"
-    "  resultIsReadOnly = true;\n"
-    "  return result.MakeReadOnly();\n"
-    "}\n\n");
-
-  if (optimize_speed()) {
-    printer->Print(
-      vars,
-      "public override Builder MergeFrom(pb::IMessage$suffix$ other) {\n"
-      "  if (other is $class_name$) {\n"
-      "    return MergeFrom(($class_name$) other);\n"
-      "  } else {\n"
-      "    base.MergeFrom(other);\n"
-      "    return this;\n"
-      "  }\n"
-      "}\n\n");
-
-    printer->Print(vars,"public override Builder MergeFrom($class_name$ other) {\n");
-    // Optimization:  If other is the default instance, we know none of its
-    // fields are set so we can skip the merge.
+  // Merge oneof fields
+  for (int i = 0; i < descriptor_->oneof_decl_count(); ++i) {
+    vars["name"] = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), false);
+    vars["property_name"] = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true);
+    printer->Print(vars, "switch (other.$property_name$Case) {\n");
     printer->Indent();
-    printer->Print(
-      vars,
-      "if (other == $full_class_name$.DefaultInstance) return this;\n"
-      "PrepareBuilder();\n");
-    for (int i = 0; i < descriptor_->field_count(); i++) {
-      if (!descriptor_->field(i)->containing_oneof()) {
-	scoped_ptr<FieldGeneratorBase> generator(
-	  CreateFieldGeneratorInternal(descriptor_->field(i)));
-	generator->GenerateMergingCode(printer);
-      }
-     }
-
-    // Merge oneof fields
-    for (int i = 0; i < descriptor_->oneof_decl_count(); ++i) {
-      vars["name"] = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), false);
-      vars["property_name"] = UnderscoresToCamelCase(descriptor_->oneof_decl(i)->name(), true);
-      printer->Print(vars, "switch (other.$property_name$Case) {\n");
-      printer->Indent();
-      for (int j = 0; j < descriptor_->oneof_decl(i)->field_count(); j++) {
-        const FieldDescriptor* field = descriptor_->oneof_decl(i)->field(j);
-	vars["field_property_name"] = GetPropertyName(field);
-	printer->Print(
-          vars,
-          "case $property_name$OneofCase.$field_property_name$: {\n");
-	if (field->type() == FieldDescriptor::TYPE_GROUP ||
-	    field->type() == FieldDescriptor::TYPE_MESSAGE) {
-	  printer->Print(
-            vars,
-            "  Merge$field_property_name$(other.$field_property_name$);\n");
-	} else {
-	  printer->Print(
-            vars,
-            "  Set$field_property_name$(other.$field_property_name$);\n");
-	}
-        printer->Print("  break;\n");
-	printer->Print("}\n");
-      }
-      printer->Print(vars, "case $property_name$OneofCase.None: { break; }\n");
-      printer->Outdent();
-      printer->Print("}\n");
-    }
-
-    // if message type has extensions
-    if (descriptor_->extension_range_count() > 0) {
-      printer->Print("  this.MergeExtensionFields(other);\n");
-    }
-    if (!use_lite_runtime()) {
-      printer->Print("this.MergeUnknownFields(other.UnknownFields);\n");
+    for (int j = 0; j < descriptor_->oneof_decl(i)->field_count(); j++) {
+      const FieldDescriptor* field = descriptor_->oneof_decl(i)->field(j);
+      vars["field_property_name"] = GetPropertyName(field);
+      printer->Print(
+        vars,
+        "case $property_name$OneofCase.$field_property_name$:\n"
+        "  $field_property_name$ = other.$field_property_name$;\n"
+        "  break;\n");
     }
-    printer->Print("return this;\n");
     printer->Outdent();
     printer->Print("}\n\n");
   }
-
-}
-
-void MessageGenerator::GenerateBuilderParsingMethods(io::Printer* printer) {
-  printer->Print(
-    "public override Builder MergeFrom(pb::ICodedInputStream input) {\n"
-    "  return MergeFrom(input, pb::ExtensionRegistry.Empty);\n"
-    "}\n\n");
-
-  printer->Print(
-    "public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {\n");
+  printer->Outdent();
+  printer->Print("}\n\n");
+  printer->Print("public void MergeFrom(pb::ICodedInputStream input) {\n");
   printer->Indent();
-  printer->Print("PrepareBuilder();\n");
-  if (!use_lite_runtime()) {
-    printer->Print("pb::UnknownFieldSet.Builder unknownFields = null;\n");
-  }
   printer->Print(
     "uint tag;\n"
-    "string field_name;\n"
-    "while (input.ReadTag(out tag, out field_name)) {\n");
+    "string fieldName;\n"
+    "while (input.ReadTag(out tag, out fieldName)) {\n"
+    "  if (tag == 0 && fieldName != null) {");
   printer->Indent();
-  printer->Print("if(tag == 0 && field_name != null) {\n");
   printer->Indent();
-  //if you change from StringComparer.Ordinal, the array sort in FieldNames { get; } must also change
-  printer->Print(
-    "int field_ordinal = global::System.Array.BinarySearch(_$camel_class_name$FieldNames, field_name, global::System.StringComparer.Ordinal);\n"
-    "if(field_ordinal >= 0)\n"
-    "  tag = _$camel_class_name$FieldTags[field_ordinal];\n"
-    "else {\n",
-    "camel_class_name", UnderscoresToCamelCase(class_name(), false));
-  if (!use_lite_runtime()) {
-    printer->Print(
-      "  if (unknownFields == null) {\n"  // First unknown field - create builder now
-      "    unknownFields = pb::UnknownFieldSet.CreateBuilder(this.UnknownFields);\n"
-      "  }\n");
-  }
   printer->Print(
-    "  ParseUnknownField(input, $prefix$extensionRegistry, tag, field_name);\n",
-    "prefix", use_lite_runtime() ? "" : "unknownFields, ");
-  printer->Print("  continue;\n");
-  printer->Print("}\n");
-  printer->Outdent();
-  printer->Print("}\n");
-
-  printer->Print("switch (tag) {\n");
+    "int fieldOrdinal = global::System.Array.BinarySearch(_fieldNames, fieldName, global::System.String.String.Ordinal);\n"
+    "if (fieldOrdinal >= 0) {\n"
+    "  tag = _fieldTags[fieldOrdinal];\n"
+    "}\n"
+    "switch(tag) {\n");
   printer->Indent();
   printer->Print(
     "case 0: {\n"  // 0 signals EOF / limit reached
     "  throw pb::InvalidProtocolBufferException.InvalidTag();\n"
     "}\n"
-    "default: {\n"
-    "  if (pb::WireFormat.IsEndGroupTag(tag)) {\n");
-  if (!use_lite_runtime()) {
-    printer->Print(
-      "    if (unknownFields != null) {\n"
-      "      this.UnknownFields = unknownFields.Build();\n"
-      "    }\n");
-  }
-  printer->Print(
-    "    return this;\n"  // it's an endgroup tag
-    "  }\n");
-  if (!use_lite_runtime()) {
-    printer->Print(
-      "  if (unknownFields == null) {\n"  // First unknown field - create builder now
-      "    unknownFields = pb::UnknownFieldSet.CreateBuilder(this.UnknownFields);\n"
-      "  }\n");
-  }
-  printer->Print(
-      "  ParseUnknownField(input, $prefix$extensionRegistry, tag, field_name);\n",
-      "prefix", use_lite_runtime() ? "" : "unknownFields, ");
-  printer->Print("  break;\n");
-  printer->Print("}\n");
-
+    "default:\n"
+    "  if (pb::WireFormat.IsEndGroupTag(tag)) {\n"
+    "    return;\n"
+    "  }\n"
+    "  break;"); // Note: we're ignoring unknown fields here.
   for (int i = 0; i < fields_by_number().size(); i++) {
     const FieldDescriptor* field = fields_by_number()[i];
     internal::WireFormatLite::WireType wt =
         internal::WireFormat::WireTypeForFieldType(field->type());
     uint32 tag = internal::WireFormatLite::MakeTag(field->number(), wt);
+    // TODO(jonskeet): Understand what this is trying to do
     if (field->is_repeated()
         && (wt == internal::WireFormatLite::WIRETYPE_VARINT
             || wt == internal::WireFormatLite::WIRETYPE_FIXED32
@@ -894,95 +426,14 @@ void MessageGenerator::GenerateBuilderParsingMethods(io::Printer* printer) {
     printer->Outdent();
     printer->Print("}\n");
   }
-
-  printer->Outdent();
-  printer->Print("}\n");
   printer->Outdent();
-  printer->Print("}\n");
-  printer->Print("\n");
-  if (!use_lite_runtime()) {
-    printer->Print(
-      "if (unknownFields != null) {\n"
-      "  this.UnknownFields = unknownFields.Build();\n"
-      "}\n");
-  }
-  printer->Print("return this;\n");
+  printer->Print("}\n"); // switch
   printer->Outdent();
-  printer->Print("}\n\n");
-}
-
-void MessageGenerator::GenerateIsInitialized(io::Printer* printer) {
-  printer->Print("public override bool IsInitialized {\n");
-  printer->Indent();
-  printer->Print("get {\n");
-  printer->Indent();
-
-  // Check that all required fields in this message are set.
-  // TODO(kenton):  We can optimize this when we switch to putting all the
-  // "has" fields into a single bitfield.
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    if (descriptor_->field(i)->is_required()) {
-      printer->Print("if (!has$property_name$) return false;\n",
-		     "property_name", GetPropertyName(descriptor_->field(i)));
-    }
-  }
-
-  // Now check that all embedded messages are initialized.
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    const FieldDescriptor* field = descriptor_->field(i);
-
-      if (field->type() != FieldDescriptor::TYPE_MESSAGE ||
-          !HasRequiredFields(field->message_type()))
-      {
-          continue;
-      }
-      // TODO(jtattermusch): shouldn't we use GetPropertyName here?
-      string propertyName = UnderscoresToPascalCase(GetFieldName(field));
-      if (field->is_repeated())
-      {
-        printer->Print(
-          "foreach ($class_name$ element in $property_name$List) {\n"
-          "  if (!element.IsInitialized) return false;\n"
-          "}\n",
-          "class_name", GetClassName(field->message_type()),
-          "property_name", propertyName);
-      }
-      else if (field->is_optional())
-      {
-        printer->Print(
-          "if (Has$property_name$) {\n"
-          "  if (!$property_name$.IsInitialized) return false;\n"
-          "}\n",
-          "property_name", propertyName);
-      }
-      else
-      {
-        printer->Print(
-          "if (!$property_name$.IsInitialized) return false;\n",
-          "property_name", propertyName);
-      }
-  }
-
-  if (descriptor_->extension_range_count() > 0) {
-    printer->Print("if (!ExtensionsAreInitialized) return false;\n");
-  }
-  printer->Print("return true;\n");
+  printer->Print("}\n"); // if
   printer->Outdent();
-  printer->Print("}\n");
+  printer->Print("}\n"); // while
   printer->Outdent();
-  printer->Print("}\n");
-  printer->Print("\n");
-}
-
-void MessageGenerator::GenerateExtensionRegistrationCode(io::Printer* printer) {
-  for (int i = 0; i < descriptor_->extension_count(); i++) {
-    ExtensionGenerator extensionGenerator(descriptor_->extension(i));
-    extensionGenerator.GenerateExtensionRegistrationCode(printer);
-  }
-  for (int i = 0; i < descriptor_->nested_type_count(); i++) {
-    MessageGenerator messageGenerator(descriptor_->nested_type(i));
-    messageGenerator.GenerateExtensionRegistrationCode(printer);
-  }
+  printer->Print("}\n\n"); // method
 }
 
 int MessageGenerator::GetFieldOrdinal(const FieldDescriptor* descriptor) {