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- """Utilities for extracting common archive formats"""
- import zipfile
- import tarfile
- import os
- import shutil
- import posixpath
- import contextlib
- from distutils.errors import DistutilsError
- from pkg_resources import ensure_directory
- __all__ = [
- "unpack_archive", "unpack_zipfile", "unpack_tarfile", "default_filter",
- "UnrecognizedFormat", "extraction_drivers", "unpack_directory",
- ]
- class UnrecognizedFormat(DistutilsError):
- """Couldn't recognize the archive type"""
- def default_filter(src, dst):
- """The default progress/filter callback; returns True for all files"""
- return dst
- def unpack_archive(filename, extract_dir, progress_filter=default_filter,
- drivers=None):
- """Unpack `filename` to `extract_dir`, or raise ``UnrecognizedFormat``
- `progress_filter` is a function taking two arguments: a source path
- internal to the archive ('/'-separated), and a filesystem path where it
- will be extracted. The callback must return the desired extract path
- (which may be the same as the one passed in), or else ``None`` to skip
- that file or directory. The callback can thus be used to report on the
- progress of the extraction, as well as to filter the items extracted or
- alter their extraction paths.
- `drivers`, if supplied, must be a non-empty sequence of functions with the
- same signature as this function (minus the `drivers` argument), that raise
- ``UnrecognizedFormat`` if they do not support extracting the designated
- archive type. The `drivers` are tried in sequence until one is found that
- does not raise an error, or until all are exhausted (in which case
- ``UnrecognizedFormat`` is raised). If you do not supply a sequence of
- drivers, the module's ``extraction_drivers`` constant will be used, which
- means that ``unpack_zipfile`` and ``unpack_tarfile`` will be tried, in that
- order.
- """
- for driver in drivers or extraction_drivers:
- try:
- driver(filename, extract_dir, progress_filter)
- except UnrecognizedFormat:
- continue
- else:
- return
- else:
- raise UnrecognizedFormat(
- "Not a recognized archive type: %s" % filename
- )
- def unpack_directory(filename, extract_dir, progress_filter=default_filter):
- """"Unpack" a directory, using the same interface as for archives
- Raises ``UnrecognizedFormat`` if `filename` is not a directory
- """
- if not os.path.isdir(filename):
- raise UnrecognizedFormat("%s is not a directory" % filename)
- paths = {
- filename: ('', extract_dir),
- }
- for base, dirs, files in os.walk(filename):
- src, dst = paths[base]
- for d in dirs:
- paths[os.path.join(base, d)] = src + d + '/', os.path.join(dst, d)
- for f in files:
- target = os.path.join(dst, f)
- target = progress_filter(src + f, target)
- if not target:
- # skip non-files
- continue
- ensure_directory(target)
- f = os.path.join(base, f)
- shutil.copyfile(f, target)
- shutil.copystat(f, target)
- def unpack_zipfile(filename, extract_dir, progress_filter=default_filter):
- """Unpack zip `filename` to `extract_dir`
- Raises ``UnrecognizedFormat`` if `filename` is not a zipfile (as determined
- by ``zipfile.is_zipfile()``). See ``unpack_archive()`` for an explanation
- of the `progress_filter` argument.
- """
- if not zipfile.is_zipfile(filename):
- raise UnrecognizedFormat("%s is not a zip file" % (filename,))
- with zipfile.ZipFile(filename) as z:
- for info in z.infolist():
- name = info.filename
- # don't extract absolute paths or ones with .. in them
- if name.startswith('/') or '..' in name.split('/'):
- continue
- target = os.path.join(extract_dir, *name.split('/'))
- target = progress_filter(name, target)
- if not target:
- continue
- if name.endswith('/'):
- # directory
- ensure_directory(target)
- else:
- # file
- ensure_directory(target)
- data = z.read(info.filename)
- with open(target, 'wb') as f:
- f.write(data)
- unix_attributes = info.external_attr >> 16
- if unix_attributes:
- os.chmod(target, unix_attributes)
- def unpack_tarfile(filename, extract_dir, progress_filter=default_filter):
- """Unpack tar/tar.gz/tar.bz2 `filename` to `extract_dir`
- Raises ``UnrecognizedFormat`` if `filename` is not a tarfile (as determined
- by ``tarfile.open()``). See ``unpack_archive()`` for an explanation
- of the `progress_filter` argument.
- """
- try:
- tarobj = tarfile.open(filename)
- except tarfile.TarError:
- raise UnrecognizedFormat(
- "%s is not a compressed or uncompressed tar file" % (filename,)
- )
- with contextlib.closing(tarobj):
- # don't do any chowning!
- tarobj.chown = lambda *args: None
- for member in tarobj:
- name = member.name
- # don't extract absolute paths or ones with .. in them
- if not name.startswith('/') and '..' not in name.split('/'):
- prelim_dst = os.path.join(extract_dir, *name.split('/'))
- # resolve any links and to extract the link targets as normal
- # files
- while member is not None and (member.islnk() or member.issym()):
- linkpath = member.linkname
- if member.issym():
- base = posixpath.dirname(member.name)
- linkpath = posixpath.join(base, linkpath)
- linkpath = posixpath.normpath(linkpath)
- member = tarobj._getmember(linkpath)
- if member is not None and (member.isfile() or member.isdir()):
- final_dst = progress_filter(name, prelim_dst)
- if final_dst:
- if final_dst.endswith(os.sep):
- final_dst = final_dst[:-1]
- try:
- # XXX Ugh
- tarobj._extract_member(member, final_dst)
- except tarfile.ExtractError:
- # chown/chmod/mkfifo/mknode/makedev failed
- pass
- return True
- extraction_drivers = unpack_directory, unpack_zipfile, unpack_tarfile
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