extract_from_cab.py (2037B)
1 #!/usr/bin/env python3 2 # Copyright 2012 The Chromium Authors 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 9 import os 10 import shutil 11 import subprocess 12 import sys 13 import tempfile 14 15 def run_quiet(*args): 16 """Run 'expand' suppressing noisy output. Returns returncode from process.""" 17 popen = subprocess.Popen(args, stdout=subprocess.PIPE) 18 out, _ = popen.communicate() 19 if popen.returncode: 20 # expand emits errors to stdout, so if we fail, then print that out. 21 print(out) 22 return popen.returncode 23 24 def main(): 25 if len(sys.argv) != 4: 26 print('Usage: extract_from_cab.py cab_path archived_file output_dir') 27 return 1 28 29 [cab_path, archived_file, output_dir] = sys.argv[1:] 30 31 # Expand.exe does its work in a fixed-named temporary directory created within 32 # the given output directory. This is a problem for concurrent extractions, so 33 # create a unique temp dir within the desired output directory to work around 34 # this limitation. 35 temp_dir = tempfile.mkdtemp(dir=output_dir) 36 37 try: 38 # Invoke the Windows expand utility to extract the file. 39 level = run_quiet('expand', cab_path, '-F:' + archived_file, temp_dir) 40 if level == 0: 41 # Move the output file into place, preserving expand.exe's behavior of 42 # paving over any preexisting file. 43 output_file = os.path.join(output_dir, archived_file) 44 try: 45 os.remove(output_file) 46 except OSError: 47 pass 48 os.rename(os.path.join(temp_dir, archived_file), output_file) 49 finally: 50 shutil.rmtree(temp_dir, True) 51 52 if level != 0: 53 return level 54 55 # The expand utility preserves the modification date and time of the archived 56 # file. Touch the extracted file. This helps build systems that compare the 57 # modification times of input and output files to determine whether to do an 58 # action. 59 os.utime(os.path.join(output_dir, archived_file), None) 60 return 0 61 62 63 if __name__ == '__main__': 64 sys.exit(main())