tools/build_rules/genproto.bzl

# Copyright 2014 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# This is a quick and dirty rule to make Bazel compile itself.  It
# only supports Java.

proto_filetype = FileType([".proto"])

def gensrcjar_impl(ctx):
  out = ctx.outputs.srcjar
  proto_output = out.path + ".proto_output"
  proto_compiler = ctx.file._proto_compiler
  sub_commands = [
    "rm -rf " + proto_output,
    "mkdir " + proto_output,
    ' '.join([proto_compiler.path, "--java_out=" + proto_output,
              ctx.file.src.path]),
    "touch -t 198001010000 $(find " + proto_output + ")",
    ctx.file._jar.path + " cMf " + out.path + " -C " + proto_output + " .",
  ]

  ctx.action(
    command=" && ".join(sub_commands),
    inputs=[ctx.file.src, proto_compiler, ctx.file._jar],
    outputs=[out],
    mnemonic="GenProtoSrcJar",
    use_default_shell_env = True)

gensrcjar = rule(
  gensrcjar_impl,
  attrs={
        "src": attr.label(allow_files=proto_filetype, single_file=True),
        # TODO(bazel-team): this should be a hidden attribute with a default
        # value, but Skylark needs to support select first.
        "_proto_compiler": attr.label(
            default=Label("//third_party:protoc"),
            allow_files=True,
            single_file=True),
        "_jar": attr.label(
            default=Label("//external:jar"),
            allow_files=True,
            single_file=True),
  },
  outputs={"srcjar": "lib%{name}.srcjar"},
)

# TODO(bazel-team): support proto => proto dependencies too
def proto_java_library(name, src):
  gensrcjar(name=name + "_srcjar", src=src)
  native.java_library(
    name=name,
    srcs=[name + "_srcjar"],
    deps=["//third_party:protobuf"])