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#!/usr/bin/env python
# Copyright (c) 2012 The Chromium Authors. All rights reserved.
# 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())
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