Since we do not run build.rs during an Android build,
we need to set up the version number in src/lib.rs
until we have a smarter way to patch it based on new
version number in Cargo.toml.

To update this package, please make sure that the following code
in src/lib.rs is up to data.

        // Hack: hard code version number here because Android.bp
        // rust modules cannot pass it though env variable yet.
        w.write_generated_by("rust-protobuf", "2.16.2");

If there are non-trivial changes in build.rs or src/lib.rs,
please rerun cargo2android.py and verify the differences in
Android.bp and src/lib.rs.

# protobuf-codegen

This crate contains protobuf code generator and a `protoc-gen-rust` `protoc` plugin.

## protoc-gen-rust

`protoc-gen-rust` implements standard protobuf `protoc` plugin conventions.

Probably you do not want to use it directly in Rust environment, there are easier to use alternatives:

* [protoc-rust crate](https://github.com/stepancheg/rust-protobuf/tree/master/protoc-rust)
  which can be invoked programmatically from `build.rs` of your project
  which requires only `protoc` in `$PATH` but not `protoc-gen-rust`.
* [protobuf-codegen-pure crate](https://github.com/stepancheg/rust-protobuf/tree/master/protobuf-codegen-pure)
  which behaves like protoc-rust, but does not depend on `protoc` binary

## But if you really want to use that plugin, here's the instruction

(Note `protoc` can be invoked programmatically with
[protoc crate](https://github.com/stepancheg/rust-protobuf/tree/master/protoc/))

0) Install protobuf for `protoc` binary.

On OS X [Homebrew](https://github.com/Homebrew/brew) can be used:

```
brew install protobuf
```

On Ubuntu, `protobuf-compiler` package can be installed:

```
apt-get install protobuf-compiler
```

Protobuf is needed only for code generation, `rust-protobuf` runtime
does not use `protobuf` library.

1) Install `protoc-gen-rust` program (which is `protoc` plugin)

It can be installed either from source or with `cargo install protobuf` command.

2) Add `protoc-gen-rust` to $PATH

If you installed it with cargo, it should be

```
PATH="$HOME/.cargo/bin:$PATH"
```

3) Generate .rs files:

```
protoc --rust_out . foo.proto
```

This will generate .rs files in current directory.