gn/standalone/proto_library.gni

# Copyright (C) 2017 The Android Open Source Project
#
# 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.

template("proto_library") {
  assert(defined(invoker.sources))
  proto_sources = invoker.sources

  # All the proto imports should be relative to the project root.
  proto_in_dir = "//"
  if (defined(invoker.proto_in_dir)) {
    proto_in_dir = invoker.proto_in_dir
  }
  assert(defined(invoker.proto_out_dir),
         "proto_out_dir must be explicitly defined")
  proto_out_dir = invoker.proto_out_dir

  # We don't support generate_python in the standalone build, but still must
  # check that the caller sets this to false. This is because when building in
  # the chromium tree, chromium's proto_library.gni in chrome (!= this) defaults
  # generate_python = true.
  assert(defined(invoker.generate_python) && !invoker.generate_python)

  # If false will not generate the default .pb.{cc,h} files. Used for custom
  # codegen plugins.
  generate_cc = true
  if (defined(invoker.generate_cc)) {
    generate_cc = invoker.generate_cc
  }

  if (defined(invoker.generator_plugin_label)) {
    plugin_host_label = invoker.generator_plugin_label + "($host_toolchain)"
    plugin_path = get_label_info(plugin_host_label, "root_out_dir") + "/" +
                  get_label_info(plugin_host_label, "name")
    generate_with_plugin = true
  } else if (defined(invoker.generator_plugin_script)) {
    plugin_path = invoker.generator_plugin_script
    generate_with_plugin = true
  } else {
    generate_with_plugin = false
  }

  if (generate_with_plugin) {
    if (defined(invoker.generator_plugin_suffix)) {
      generator_plugin_suffixes = [
        "${invoker.generator_plugin_suffix}.h",
        "${invoker.generator_plugin_suffix}.cc",
      ]
    } else {
      generator_plugin_suffixes = invoker.generator_plugin_suffixes
    }
  }

  cc_out_dir = "$root_gen_dir/" + proto_out_dir
  rel_cc_out_dir = rebase_path(cc_out_dir, root_build_dir)

  protos = rebase_path(proto_sources, proto_in_dir)
  protogens = []

  foreach(proto, protos) {
    proto_dir = get_path_info(proto, "dir")
    proto_name = get_path_info(proto, "name")
    proto_path = proto_dir + "/" + proto_name

    if (generate_cc) {
      protogens += [
        "$cc_out_dir/$proto_path.pb.h",
        "$cc_out_dir/$proto_path.pb.cc",
      ]
    }
    if (generate_with_plugin) {
      foreach(suffix, generator_plugin_suffixes) {
        protogens += [ "$cc_out_dir/${proto_path}${suffix}" ]
      }
    }
  }

  config_name = "${target_name}_config"
  action_name = "${target_name}_gen"
  source_set_name = target_name

  config(config_name) {
    include_dirs = [ cc_out_dir ]
  }

  # The XXX_gen action that generates the .pb.{cc,h} files.
  action(action_name) {
    visibility = [ ":$source_set_name" ]
    script = "//gn/standalone/build_tool_wrapper.py"
    sources = proto_sources
    outputs = get_path_info(protogens, "abspath")

    protoc_label = "//buildtools:protoc($host_toolchain)"
    protoc_path = get_label_info(protoc_label, "root_out_dir") + "/protoc"
    args = [
      # Path should be rebased because |root_build_dir| for current toolchain
      # may be different from |root_out_dir| of protoc built on host toolchain.
      "./" + rebase_path(protoc_path, root_build_dir),
      "--proto_path",
      rebase_path(proto_in_dir, root_build_dir),
    ]
    if (generate_cc) {
      args += [
        "--cpp_out",
        rel_cc_out_dir,
      ]
    }

    if (generate_with_plugin) {
      plugin_path_rebased = rebase_path(plugin_path, root_build_dir)
      plugin_out_args = ""
      if (defined(invoker.generator_plugin_options)) {
        plugin_out_args += invoker.generator_plugin_options
      }
      plugin_out_args += ":$rel_cc_out_dir"

      args += [
        "--plugin=protoc-gen-plugin=$plugin_path_rebased",
        "--plugin_out=$plugin_out_args",
      ]
    }

    args += rebase_path(proto_sources, root_build_dir)

    inputs = [
      protoc_path,
    ]

    deps = [
      protoc_label,
    ]
    if (generate_with_plugin) {
      inputs += [ plugin_path ]
      if (defined(plugin_host_label)) {
        # Action depends on native generator plugin but for host toolchain only.
        deps += [ plugin_host_label ]
      }
    }

    if (defined(invoker.deps)) {
      deps += invoker.deps
    }
  }  # action "${target_name}_gen"

  # The source_set that builds the generated .pb.cc files.
  source_set(target_name) {
    forward_variables_from(invoker,
                           [
                             "defines",
                             "include_dirs",
                             "public_configs",
                             "testonly",
                             "visibility",
                           ])

    sources = get_target_outputs(":$action_name")

    configs -= [ "//gn/standalone:extra_warnings" ]
    if (defined(invoker.extra_configs)) {
      configs += invoker.extra_configs
    }

    if (!defined(invoker.public_configs)) {
      public_configs = []
    }

    public_configs += [
      "//buildtools:protobuf_gen_config",
      ":$config_name",
    ]

    # Use protobuf_full only for tests.
    if (defined(invoker.use_protobuf_full) &&
        invoker.use_protobuf_full == true) {
      deps = [
        "//buildtools:protobuf_full",
      ]
    } else {
      deps = [
        "//buildtools:protobuf_lite",
      ]
    }

    deps += [ ":$action_name" ]
    if (defined(invoker.deps)) {
      deps += invoker.deps
    }
  }  # source_set(target_name)
}  # template