protoc: Add options to redirect input / output to files.

What is the problem?
When used with --encode / --decode / --decode_raw options, protoc expects 
intput from stdin and dumps it to stdout.

While it is easy to wrap this in a script to read/write to files, this is 
slightly harder to do with some build systems (in my case gyp). 

What is the expected output? What do you see instead?
Add command line flags --protbuf_in and --protobuf_out to be used with the 
ecode/decode/raw_decode flags to read/write from files.

What version of the product are you using? On what operating system?
ToT: SVN revision r517.

I'll contribute a patch.

Original issue reported on code.google.com by ppra...@google.com on 7 Mar 2014 at 3:01

kidok / protobuf

protoc: Add options to redirect input / output to files. #613