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# Copyright (c) 2015, Google Inc.
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""Extracts archives."""
import optparse
import os
import os.path
import tarfile
import shutil
import sys
import zipfile
def CheckedJoin(output, path):
"""
CheckedJoin returns os.path.join(output, path). It does sanity checks to
ensure the resulting path is under output, but shouldn't be used on untrusted
input.
"""
path = os.path.normpath(path)
if os.path.isabs(path) or path.startswith('.'):
raise ValueError(path)
return os.path.join(output, path)
def IterateZip(path):
"""
IterateZip opens the zip file at path and returns a generator of
(filename, mode, fileobj) tuples for each file in it.
"""
with zipfile.ZipFile(path, 'r') as zip_file:
for info in zip_file.infolist():
if info.filename.endswith('/'):
continue
yield (info.filename, None, zip_file.open(info))
def IterateTar(path):
"""
IterateTar opens the tar.gz file at path and returns a generator of
(filename, mode, fileobj) tuples for each file in it.
"""
with tarfile.open(path, 'r:gz') as tar_file:
for info in tar_file:
if info.isdir():
continue
if not info.isfile():
raise ValueError('Unknown entry type "%s"' % (info.name, ))
yield (info.name, info.mode, tar_file.extractfile(info))
def main(args):
parser = optparse.OptionParser(usage='Usage: %prog ARCHIVE OUTPUT')
parser.add_option('--no-prefix', dest='no_prefix', action='store_true',
help='Do not remove a prefix from paths in the archive.')
options, args = parser.parse_args(args)
if len(args) != 2:
parser.print_help()
return 1
archive, output = args
if not os.path.exists(archive):
# Skip archives that weren't downloaded.
return 0
if archive.endswith('.zip'):
entries = IterateZip(archive)
elif archive.endswith('.tar.gz'):
entries = IterateTar(archive)
else:
raise ValueError(archive)
try:
if os.path.exists(output):
print "Removing %s" % (output, )
shutil.rmtree(output)
print "Extracting %s to %s" % (archive, output)
prefix = None
num_extracted = 0
for path, mode, inp in entries:
# Even on Windows, zip files must always use forward slashes.
if '\\' in path or path.startswith('/'):
raise ValueError(path)
if not options.no_prefix:
new_prefix, rest = path.split('/', 1)
# Ensure the archive is consistent.
if prefix is None:
prefix = new_prefix
if prefix != new_prefix:
raise ValueError((prefix, new_prefix))
else:
rest = path
# Extract the file into the output directory.
fixed_path = CheckedJoin(output, rest)
if not os.path.isdir(os.path.dirname(fixed_path)):
os.makedirs(os.path.dirname(fixed_path))
with open(fixed_path, 'wb') as out:
shutil.copyfileobj(inp, out)
# Fix up permissions if needbe.
# TODO(davidben): To be extra tidy, this should only track the execute bit
# as in git.
if mode is not None:
os.chmod(fixed_path, mode)
# Print every 100 files, so bots do not time out on large archives.
num_extracted += 1
if num_extracted % 100 == 0:
print "Extracted %d files..." % (num_extracted,)
finally:
entries.close()
if num_extracted % 100 == 0:
print "Done. Extracted %d files." % (num_extracted,)
return 0
if __name__ == '__main__':
sys.exit(main(sys.argv[1:]))
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