Mon, Feb 16, 2015
- .proto is used as spec and to generate generator/parser for several languages. No need to write your own (you can if you want). And tool, game, engine spend less time on creating generator/parser. Developper only need to create adapter, converter into their own format (far easier than creating generator + parser).
- protobuf have support for lot of programming language (my priority order):
- python : blender exporter, realtime renderer is my first target as tool.
- c/c++, java : lot of tools, game-engine are writen in C/C++ and jmonkeyengine are my first target as game engine.
- c# : used by unity3d
- type checking (at compile time or runtime) is developper friendly.
- often protobuf will generate better parser (error reporting) than hand written.
- a realy open/free format with source, doc hosted on public repository (github)
- protobuf have an ecosystem, port, ide support,…
- file are binary, not text.
- pros : size
- cons : impossible to read or to edit content with a text editor, not scm (git, svn) friendly (like for image ;-) )
- Why not, flatbuffers, capnproto ? because not mature/developper friendly enough for my first target language (python, java, c/c++), may be for an other adaptation
- Why not, msgpack, json, yaml,… ? they require to write doc spec, and to create generator/parser. Same issue than OpenGEX and ODDL.
- Protobuf is not the best in size of the content, or the best is performence (reading/writing), has code generator,… but it’s the optimal for my target (see ‘Why ?’)
- Quality for protoc plugins is very variable between language. Some languages have several generators (eg: python, c#).
- For python3 I need to convert the package protobuf-2.6.1 to python 3 (via a simple script)
- Using an intermediary (pivot) format generate lot of copy (eg: conversion from internal vec3 to xbuf vec3) :overhead at coding time and runtime.
- IDL (.proto) limitations :
- no range for values
- no invariant rules about value (like pattern matching, min, max, …)
- no rules (min, max, fixed, multiple of …) about size of list (repeated)
- no readonly/immutable value
See also FAQ