build/extract_from_cab.py

   1 #!/usr/bin/env python
   2 # Copyright (c) 2011 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
   8 import os
   9 import shutil
  10 import subprocess
  11 import sys
  12 import tempfile
  13
  14
  15 def main():
  16   if len(sys.argv) != 4:
  17     print 'Usage: extract_from_cab.py cab_path archived_file output_dir'
  18     return 1
  19
  20   [cab_path, archived_file, output_dir] = sys.argv[1:]
  21
  22   # Expand.exe does its work in a fixed-named temporary directory created within
  23   # the given output directory. This is a problem for concurrent extractions, so
  24   # create a unique temp dir within the desired output directory to work around
  25   # this limitation.
  26   temp_dir = tempfile.mkdtemp(dir=output_dir)
  27
  28   try:
  29     # Invoke the Windows expand utility to extract the file.
  30     level = subprocess.call(
  31         ['expand', cab_path, '-F:' + archived_file, temp_dir])
  32     if level == 0:
  33       # Move the output file into place, preserving expand.exe's behavior of
  34       # paving over any preexisting file.
  35       output_file = os.path.join(output_dir, archived_file)
  36       try:
  37         os.remove(output_file)
  38       except OSError:
  39         pass
  40       os.rename(os.path.join(temp_dir, archived_file), output_file)
  41   finally:
  42     shutil.rmtree(temp_dir, True)
  43
  44   if level != 0:
  45     return level
  46
  47   # The expand utility preserves the modification date and time of the archived
  48   # file. Touch the extracted file. This helps build systems that compare the
  49   # modification times of input and output files to determine whether to do an
  50   # action.
  51   os.utime(os.path.join(output_dir, archived_file), None)
  52   return 0
  53
  54
  55 if __name__ == '__main__':
  56   sys.exit(main())