#!/usr/bin/env python3
# Copyright 2012 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Extracts a single file from a CAB archive."""

import os
import shutil
import subprocess
import sys
import tempfile


def run_quiet(*args):
    """Run 'expand' suppressing noisy output. Returns returncode from process."""
    popen = subprocess.Popen(args, stdout=subprocess.PIPE)
    out, _ = popen.communicate()
    if popen.returncode:
        # expand emits errors to stdout, so if we fail, then print that out.
        print(out)
    return popen.returncode


def main():
    if len(sys.argv) != 4:
        print('Usage: extract_from_cab.py cab_path archived_file output_dir')
        return 1

    [cab_path, archived_file, output_dir] = sys.argv[1:]

    # Expand.exe does its work in a fixed-named temporary directory created within
    # the given output directory. This is a problem for concurrent extractions, so
    # create a unique temp dir within the desired output directory to work around
    # this limitation.
    temp_dir = tempfile.mkdtemp(dir=output_dir)

    try:
        # Invoke the Windows expand utility to extract the file.
        level = run_quiet('expand', cab_path, '-F:' + archived_file, temp_dir)
        if level == 0:
            # Move the output file into place, preserving expand.exe's behavior of
            # paving over any preexisting file.
            output_file = os.path.join(output_dir, archived_file)
            try:
                os.remove(output_file)
            except OSError:
                pass
            os.rename(os.path.join(temp_dir, archived_file), output_file)
    finally:
        shutil.rmtree(temp_dir, True)

    if level != 0:
        return level

    # The expand utility preserves the modification date and time of the archived
    # file. Touch the extracted file. This helps build systems that compare the
    # modification times of input and output files to determine whether to do an
    # action.
    os.utime(os.path.join(output_dir, archived_file), None)
    return 0


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