pw_build/relative_source_file_names.gni

# Copyright 2022 The Pigweed Authors
#
# 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
#
#     https://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.

import("//build_overrides/pigweed.gni")

import("$dir_pw_build/python_action.gni")

# This isn't in a declare_args() block as it likely isn't necessary to change
# this.
pw_build_RELATIVE_PATH_TRANSFORM_JSON =
    "$root_build_dir/relative_path_transformations.json"

# Creates a JSON file containing an array of source file names with
# -ffile-prefix-map style transformations applied to match __FILE__ as seen in
# C/C++ sources when using pw_build's `relative_paths` config.
#
# Args:
#    deps (required): A list of targets to recursively extract file names from.
#    outputs (required): An array with a single element: the path to write the
#        transformed file paths to. The output format is a JSON array of
#        strings.
template("pw_relative_source_file_names") {
  _raw_file_names_json = "$target_gen_dir/${target_name}.raw.json"

  # The various pw_* templates add pw_source_files metadata which we
  # aggregate here.
  generated_file("${target_name}.raw_source_files") {
    forward_variables_from(invoker, [ "deps" ])

    # Rebase the paths so that they match those that are passed to the
    # compiler.
    rebase = root_build_dir
    outputs = [ _raw_file_names_json ]
    data_keys = [ "pw_source_files" ]
    output_conversion = "json"
  }

  pw_python_action(target_name) {
    deps = [ ":${target_name}.raw_source_files" ]
    python_deps = [ "$dir_pw_build/py" ]
    module = "pw_build.file_prefix_map"

    # GN-ism: You can't do invoker.outputs[0], but _outs[0] works.
    _outs = invoker.outputs
    args = [
      rebase_path(_raw_file_names_json, root_build_dir),
      "--prefix-map-json",
      rebase_path(pw_build_RELATIVE_PATH_TRANSFORM_JSON, root_build_dir),
      "--out",
      rebase_path(_outs[0], root_build_dir),
    ]

    inputs = [ _raw_file_names_json ]
    forward_variables_from(invoker, [ "outputs" ])
  }
}