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