build/util/BUILD.gn

# Copyright (c) 2013 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# This target generates a "last_change.h" header file in the generated files
# directory that contains a define of the last revision of the source tree
# of the form:
#  #define LAST_CHANGE "123456"
#
# The version is a string rather than an integer for extra flexibility (for
# example, we may require git hashes in the future).
#
# All you need to do is depend on this target, and then from your source code:
#  #include "build/util/last_change.h"
action("last_change") {
  script = "//build/util/lastchange.py"

  # This script must be run before targets depending on us.
  hard_dep = true

  # Rerun the script any time this file changes.
  source_prereqs = [ "//build/util/LASTCHANGE" ]

  output_header = "$target_gen_dir/last_change.h"
  outputs = [ output_header ]

  build_relative_src = rebase_path("//", root_build_dir)
  build_relative_outputs = rebase_path(output_header, root_build_dir)

  args = [
    "--source-dir=$build_relative_src",
    "--header=$build_relative_outputs",
    "--version-macro=LAST_CHANGE",
  ]
}