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Protocol Buffers v2.5.0

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@xfxyjwf xfxyjwf released this 25 Mar 00:49

Version 2.5.0

General

  • New notion "import public" that allows a proto file to forward the content
    it imports to its importers. For example,

    // foo.proto
    import public "bar.proto";
    import "baz.proto";
    
    // qux.proto
    import "foo.proto";
    // Stuff defined in bar.proto may be used in this file, but stuff from
    // baz.proto may NOT be used without importing it explicitly.
    

    This is useful for moving proto files. To move a proto file, just leave
    a single "import public" in the old proto file.

  • New enum option "allow_alias" that specifies whether different symbols can
    be assigned the same numeric value. Default value is "true". Setting it to
    false causes the compiler to reject enum definitions where multiple symbols
    have the same numeric value.
    Note: We plan to flip the default value to "false" in a future release.
    Projects using enum aliases should set the option to "true" in their .proto
    files.

C++

  • New generated method set_allocated_foo(Type* foo) for message and string
    fields. This method allows you to set the field to a pre-allocated object
    and the containing message takes the ownership of that object.
  • Added SetAllocatedExtension() and ReleaseExtension() to extensions API.
  • Custom options are now formatted correctly when descriptors are printed in
    text format.
  • Various speed optimizations.

Java

  • Comments in proto files are now collected and put into generated code as
    comments for corresponding classes and data members.

  • Added Parser to parse directly into messages without a Builder. For
    example,

    Foo foo = Foo.PARSER.ParseFrom(input);
    

    Using Parser is ~25% faster than using Builder to parse messages.

  • Added getters/setters to access the underlying ByteString of a string field
    directly.

  • ByteString now supports more operations: substring(), prepend(), and
    append(). The implementation of ByteString uses a binary tree structure
    to support these operations efficiently.

  • New method findInitializationErrors() that lists all missing required
    fields.

  • Various code size and speed optimizations.

Python

  • Added support for dynamic message creation. DescriptorDatabase,
    DescriptorPool, and MessageFactory work like their C++ couterparts to
    simplify Descriptor construction from *DescriptorProtos, and MessageFactory
    provides a message instance from a Descriptor.
  • Added pickle support for protobuf messages.
  • Unknown fields are now preserved after parsing.
  • Fixed bug where custom options were not correctly populated. Custom
    options can be accessed now.
  • Added EnumTypeWrapper that provides better accessibility to enum types.
  • Added ParseMessage(descriptor, bytes) to generate a new Message instance
    from a descriptor and a byte string.