build/depfile_path_to_relative.py

#!/usr/bin/env python3.8
# Copyright 2021 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import argparse
import os
import subprocess
import sys


def main():
    parser = argparse.ArgumentParser(
        description=
        'Executes a command, then rewrites the depfile, converts all absolute paths to relative'
    )
    parser.add_argument(
        '--depfile', help='Path to the depfile to rewrite', required=True)
    parser.add_argument(
        'command', nargs='+', help='Positional args for the command to run')
    args = parser.parse_args()

    retval = subprocess.call(args.command)
    if retval != 0:
        return retval

    lines = []
    with open(args.depfile, 'r') as f:
        for line in f:
            lines.append(' '.join(os.path.relpath(p) for p in line.split()))
    with open(args.depfile, 'w') as f:
        f.write('\n'.join(lines))


if __name__ == '__main__':
    sys.exit(main())