C# IBuilder.CreateBuilderForField方法代码示例

        /// <summary>
        /// Parses a single field from the specified tokenizer and merges it into
        /// the builder.
        /// </summary>
        private static void MergeField(TextTokenizer tokenizer, ExtensionRegistry extensionRegistry,
                                       IBuilder builder)
        {
            FieldDescriptor field;
            MessageDescriptor type = builder.DescriptorForType;
            ExtensionInfo extension = null;

            if (tokenizer.TryConsume("["))
            {
                // An extension.
                StringBuilder name = new StringBuilder(tokenizer.ConsumeIdentifier());
                while (tokenizer.TryConsume("."))
                {
                    name.Append(".");
                    name.Append(tokenizer.ConsumeIdentifier());
                }

                extension = extensionRegistry.FindByName(type, name.ToString());

                if (extension == null)
                {
                    throw tokenizer.CreateFormatExceptionPreviousToken("Extension \"" + name +
                                                                       "\" not found in the ExtensionRegistry.");
                }
                else if (extension.Descriptor.ContainingType != type)
                {
                    throw tokenizer.CreateFormatExceptionPreviousToken("Extension \"" + name +
                                                                       "\" does not extend message type \"" +
                                                                       type.FullName + "\".");
                }

                tokenizer.Consume("]");

                field = extension.Descriptor;
            }
            else
            {
                String name = tokenizer.ConsumeIdentifier();
                field = type.FindDescriptor<FieldDescriptor>(name);

                // Group names are expected to be capitalized as they appear in the
                // .proto file, which actually matches their type names, not their field
                // names.
                if (field == null)
                {
                    // Explicitly specify the invariant culture so that this code does not break when
                    // executing in Turkey.
                    String lowerName = name.ToLowerInvariant();
                    field = type.FindDescriptor<FieldDescriptor>(lowerName);
                    // If the case-insensitive match worked but the field is NOT a group,
                    // TODO(jonskeet): What? Java comment ends here!
                    if (field != null && field.FieldType != FieldType.Group)
                    {
                        field = null;
                    }
                }
                // Again, special-case group names as described above.
                if (field != null && field.FieldType == FieldType.Group && field.MessageType.Name != name)
                {
                    field = null;
                }

                if (field == null)
                {
                    throw tokenizer.CreateFormatExceptionPreviousToken(
                        "Message type \"" + type.FullName + "\" has no field named \"" + name + "\".");
                }
            }

            object value = null;

            if (field.MappedType == MappedType.Message)
            {
                tokenizer.TryConsume(":"); // optional

                String endToken;
                if (tokenizer.TryConsume("<"))
                {
                    endToken = ">";
                }
                else
                {
                    tokenizer.Consume("{");
                    endToken = "}";
                }

                IBuilder subBuilder;
                if (extension == null)
                {
                    subBuilder = builder.CreateBuilderForField(field);
                }
                else
                {
                    subBuilder = extension.DefaultInstance.WeakCreateBuilderForType() as IBuilder;
                    if (subBuilder == null)
                    {
//.........这里部分代码省略.........

 /// <summary>
 /// Calls parent.CreateBuilderForField() or uses the extension registry
 /// to find an appropriate builder, depending on what type is being tested.
 /// </summary>
 private IBuilder CreateBuilderForField(IBuilder parent, FieldDescriptor field)
 {
     if (extensionRegistry == null)
     {
         return parent.CreateBuilderForField(field);
     }
     else
     {
         ExtensionInfo extension = extensionRegistry[field.ContainingType, field.FieldNumber];
         Assert.NotNull(extension);
         Assert.NotNull(extension.DefaultInstance);
         return (IBuilder) extension.DefaultInstance.WeakCreateBuilderForType();
     }
 }

            /// <summary>
            /// Like <see cref="MergeFrom(CodedInputStream, ExtensionRegistry, IBuilder)" />
            /// but parses a single field.
            /// </summary>
            /// <param name="input">The input to read the field from</param>
            /// <param name="extensionRegistry">Registry to use when an extension field is encountered</param>
            /// <param name="builder">Builder to merge field into, if it's a known field</param>
            /// <param name="tag">The tag, which should already have been read from the input</param>
            /// <returns>true unless the tag is an end-group tag</returns>
            internal bool MergeFieldFrom(CodedInputStream input, 
          ExtensionRegistry extensionRegistry, IBuilder builder, uint tag)
            {
                MessageDescriptor type = builder.DescriptorForType;
                if (type.Options.MessageSetWireFormat && tag == WireFormat.MessageSetTag.ItemStart) {
                  MergeMessageSetExtensionFromCodedStream(input, extensionRegistry, builder);
                  return true;
                }

                WireFormat.WireType wireType = WireFormat.GetTagWireType(tag);
                int fieldNumber = WireFormat.GetTagFieldNumber(tag);

                FieldDescriptor field;
                IMessage defaultFieldInstance = null;

                if (type.IsExtensionNumber(fieldNumber)) {
                  ExtensionInfo extension = extensionRegistry[type, fieldNumber];
                  if (extension == null) {
                field = null;
                  } else {
                field = extension.Descriptor;
                defaultFieldInstance = extension.DefaultInstance;
                  }
                } else {
                  field = type.FindFieldByNumber(fieldNumber);
                }

                // Unknown field or wrong wire type. Skip.
                if (field == null || wireType != WireFormat.GetWireType(field)) {
                  return MergeFieldFrom(tag, input);
                }

                if (field.IsPacked) {
                  int length = (int)input.ReadRawVarint32();
                  int limit = input.PushLimit(length);
                  if (field.FieldType == FieldType.Enum) {
                while (!input.ReachedLimit) {
                  int rawValue = input.ReadEnum();
                  object value = field.EnumType.FindValueByNumber(rawValue);
                  if (value == null) {
                // If the number isn't recognized as a valid value for this
                // enum, drop it (don't even add it to unknownFields).
                return true;
                  }
                  builder.WeakAddRepeatedField(field, value);
                }
                  } else {
                while (!input.ReachedLimit) {
                  Object value = input.ReadPrimitiveField(field.FieldType);
                  builder.WeakAddRepeatedField(field, value);
                }
                  }
                  input.PopLimit(limit);
                } else {
                  object value;
                  switch (field.FieldType) {
                case FieldType.Group:
                case FieldType.Message: {
                IBuilder subBuilder;
                if (defaultFieldInstance != null) {
                  subBuilder = defaultFieldInstance.WeakCreateBuilderForType();
                } else {
                  subBuilder = builder.CreateBuilderForField(field);
                }
                if (!field.IsRepeated) {
                  subBuilder.WeakMergeFrom((IMessage)builder[field]);
                }
                if (field.FieldType == FieldType.Group) {
                  input.ReadGroup(field.FieldNumber, subBuilder, extensionRegistry);
                } else {
                  input.ReadMessage(subBuilder, extensionRegistry);
                }
                value = subBuilder.WeakBuild();
                break;
                  }
                case FieldType.Enum: {
                int rawValue = input.ReadEnum();
                value = field.EnumType.FindValueByNumber(rawValue);
                // If the number isn't recognized as a valid value for this enum,
                // drop it.
                if (value == null) {
                  MergeVarintField(fieldNumber, (ulong)rawValue);
                  return true;
                }
                break;
                  }
                default:
                  value = input.ReadPrimitiveField(field.FieldType);
                  break;
                  }
                  if (field.IsRepeated) {
//.........这里部分代码省略.........

            /// <summary>
            /// Like <see cref="MergeFrom(ICodedInputStream, ExtensionRegistry, IBuilder)" />
            /// but parses a single field.
            /// </summary>
            /// <param name="input">The input to read the field from</param>
            /// <param name="extensionRegistry">Registry to use when an extension field is encountered</param>
            /// <param name="builder">Builder to merge field into, if it's a known field</param>
            /// <param name="tag">The tag, which should already have been read from the input</param>
            /// <returns>true unless the tag is an end-group tag</returns>
            internal bool MergeFieldFrom(ICodedInputStream input,
                                         ExtensionRegistry extensionRegistry, IBuilder builder, uint tag,
                                         string fieldName)
            {
                if (tag == 0 && fieldName != null)
                {
                    FieldDescriptor fieldByName = builder.DescriptorForType.FindFieldByName(fieldName);
                    if (fieldByName != null)
                    {
                        tag = WireFormat.MakeTag(fieldByName);
                    }
                    else
                    {
                        ExtensionInfo extension = extensionRegistry.FindByName(builder.DescriptorForType, fieldName);
                        if (extension != null)
                        {
                            tag = WireFormat.MakeTag(extension.Descriptor);
                        }
                    }
                }

                MessageDescriptor type = builder.DescriptorForType;
                if (type.Options.MessageSetWireFormat && tag == WireFormat.MessageSetTag.ItemStart)
                {
                    MergeMessageSetExtensionFromCodedStream(input, extensionRegistry, builder);
                    return true;
                }

                WireFormat.WireType wireType = WireFormat.GetTagWireType(tag);
                int fieldNumber = WireFormat.GetTagFieldNumber(tag);

                FieldDescriptor field;
                IMessageLite defaultFieldInstance = null;

                if (type.IsExtensionNumber(fieldNumber))
                {
                    ExtensionInfo extension = extensionRegistry[type, fieldNumber];
                    if (extension == null)
                    {
                        field = null;
                    }
                    else
                    {
                        field = extension.Descriptor;
                        defaultFieldInstance = extension.DefaultInstance;
                    }
                }
                else
                {
                    field = type.FindFieldByNumber(fieldNumber);
                }

                // Unknown field or wrong wire type. Skip.
                if (field == null)
                {
                    return MergeFieldFrom(tag, input);
                }
                if (wireType != WireFormat.GetWireType(field))
                {
                    WireFormat.WireType expectedType = WireFormat.GetWireType(field.FieldType);
                    if (wireType == expectedType)
                    {
                        //Allowed as of 2.3, this is unpacked data for a packed array
                    }
                    else if (field.IsRepeated && wireType == WireFormat.WireType.LengthDelimited &&
                             (expectedType == WireFormat.WireType.Varint || expectedType == WireFormat.WireType.Fixed32 ||
                              expectedType == WireFormat.WireType.Fixed64))
                    {
                        //Allowed as of 2.3, this is packed data for an unpacked array
                    }
                    else
                    {
                        return MergeFieldFrom(tag, input);
                    }
                }

                switch (field.FieldType)
                {
                    case FieldType.Group:
                    case FieldType.Message:
                        {
                            IBuilderLite subBuilder = (defaultFieldInstance != null)
                                                          ? defaultFieldInstance.WeakCreateBuilderForType()
                                                          : builder.CreateBuilderForField(field);
                            if (!field.IsRepeated)
                            {
                                subBuilder.WeakMergeFrom((IMessageLite) builder[field]);
                                if (field.FieldType == FieldType.Group)
                                {
                                    input.ReadGroup(field.FieldNumber, subBuilder, extensionRegistry);
                                }
//.........这里部分代码省略.........