1#!/usr/bin/env python
2# Copyright (c) 2012 The Chromium Authors. All rights reserved.
3# Use of this source code is governed by a BSD-style license that can be
4# found in the LICENSE file.
5
6"""Extracts a single file from a CAB archive."""
7
8from __future__ import print_function
9
10import os
11import shutil
12import subprocess
13import sys
14import tempfile
15
16def run_quiet(*args):
17  """Run 'expand' suppressing noisy output. Returns returncode from process."""
18  popen = subprocess.Popen(args, stdout=subprocess.PIPE)
19  out, _ = popen.communicate()
20  if popen.returncode:
21    # expand emits errors to stdout, so if we fail, then print that out.
22    print(out)
23  return popen.returncode
24
25def main():
26  if len(sys.argv) != 4:
27    print('Usage: extract_from_cab.py cab_path archived_file output_dir')
28    return 1
29
30  [cab_path, archived_file, output_dir] = sys.argv[1:]
31
32  # Expand.exe does its work in a fixed-named temporary directory created within
33  # the given output directory. This is a problem for concurrent extractions, so
34  # create a unique temp dir within the desired output directory to work around
35  # this limitation.
36  temp_dir = tempfile.mkdtemp(dir=output_dir)
37
38  try:
39    # Invoke the Windows expand utility to extract the file.
40    level = run_quiet('expand', cab_path, '-F:' + archived_file, temp_dir)
41    if level == 0:
42      # Move the output file into place, preserving expand.exe's behavior of
43      # paving over any preexisting file.
44      output_file = os.path.join(output_dir, archived_file)
45      try:
46        os.remove(output_file)
47      except OSError:
48        pass
49      os.rename(os.path.join(temp_dir, archived_file), output_file)
50  finally:
51    shutil.rmtree(temp_dir, True)
52
53  if level != 0:
54    return level
55
56  # The expand utility preserves the modification date and time of the archived
57  # file. Touch the extracted file. This helps build systems that compare the
58  # modification times of input and output files to determine whether to do an
59  # action.
60  os.utime(os.path.join(output_dir, archived_file), None)
61  return 0
62
63
64if __name__ == '__main__':
65  sys.exit(main())
66