mkpbcopy - generate a safe Deep or Shallow Copy of a protobuf

Golang structs generated by protoc can only copied by using a Clone() method. Trying to copy a struct mymsg = *protomsg will result in an error as a lock will prevent the copy.

mkpbcopy is a program that will generated a code that will allow for either a deep or shallow copy of the entire protobuf.

Usage

usage: mkpbcopy -m <message> [-o <output>] <file>.pb.go

  -m <message>  Protobuf message to generate a copy function from
  -o <output>   Outpfile file.  If not specified defaults to <message>.go

<file>.pb.go is the protoc generated output file for a protobuf

Generated file

The generated go file is expected to be in the same directory as the original .pb.go, as it will export additional methods on the protobuf.

The two methods will will generated if <message.go> will be:

func (*Message) DeepCopy() *Message

DeepCopy will walk every element in Message, making an copy of every element, recursively traversing all elements contained by Message. This is analagous to proto.Message.Clone() but benchmarks twice as fast.

DeepCopy methods will exist for each sub message of Message.

func (*Message) ShallowCopy() *Message

ShallowCopy will only walk every native type in Message making an copy of each element. Pointers will remain unchanged.

Contributing

Please feel free to submit issues, fork the repository and send pull requests! Feedback is always welcome.

When submitting an issue, please include an example that demonstrates the issue.