text: """
  Based on "python-archive" -- http://pypi.python.org/pypi/python-archive/
  
  Copyright (c) 2010 Gary Wilson Jr. <gary.wilson@gmail.com> and contributors.
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
  
  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
  """
  import os
  import shutil
  import stat
  import tarfile
  import zipfile
  
  from django.utils import six
  
  
  class ArchiveException(Exception):
      """
      Base exception class for all archive errors.
      """
  
  
  class UnrecognizedArchiveFormat(ArchiveException):
      """
      Error raised when passed file is not a recognized archive format.
      """
  
  
  def extract(path, to_path=''):
      """
      Unpack the tar or zip file at the specified path to the directory
      specified by to_path.
      """
      with Archive(path) as archive:
          archive.extract(to_path)
  
  
  class Archive(object):
      """
      The external API class that encapsulates an archive implementation.
      """
      def __init__(self, file):
          self._archive = self._archive_cls(file)(file)
  
      @staticmethod
      def _archive_cls(file):
          cls = None
          if isinstance(file, six.string_types):
              filename = file
          else:
              try:
                  filename = file.name
              except AttributeError:
                  raise UnrecognizedArchiveFormat(
                      "File object not a recognized archive format.")
          base, tail_ext = os.path.splitext(filename.lower())
          cls = extension_map.get(tail_ext)
          if not cls:
              base, ext = os.path.splitext(base)
              cls = extension_map.get(ext)
          if not cls:
              raise UnrecognizedArchiveFormat(
                  "Path not a recognized archive format: %s" % filename)
          return cls
  
      def __enter__(self):
          return self
  
      def __exit__(self, exc_type, exc_value, traceback):
          self.close()
  
      def extract(self, to_path=''):
          self._archive.extract(to_path)
  
      def list(self):
          self._archive.list()
  
      def close(self):
          self._archive.close()
  
  
  class BaseArchive(object):
      """
      Base Archive class.  Implementations should inherit this class.
      """
      @staticmethod
      def _copy_permissions(mode, filename):
          """
          If the file in the archive has some permissions (this assumes a file
          won't be writable/executable without being readable), apply those
          permissions to the unarchived file.
          """
          if mode & stat.S_IROTH:
              os.chmod(filename, mode)
  
      def split_leading_dir(self, path):
          path = str(path)
          path = path.lstrip('/').lstrip('\\')
          if '/' in path and (('\\' in path and path.find('/') < path.find('\\')) or '\\' not in path):
              return path.split('/', 1)
          elif '\\' in path:
              return path.split('\\', 1)
          else:
              return path, ''
  
      def has_leading_dir(self, paths):
          """
          Returns true if all the paths have the same leading path name
          (i.e., everything is in one subdirectory in an archive)
          """
          common_prefix = None
          for path in paths:
              prefix, rest = self.split_leading_dir(path)
              if not prefix:
                  return False
              elif common_prefix is None:
                  common_prefix = prefix
              elif prefix != common_prefix:
                  return False
          return True
  
      def extract(self):
          raise NotImplementedError('subclasses of BaseArchive must provide an extract() method')
  
      def list(self):
          raise NotImplementedError('subclasses of BaseArchive must provide a list() method')
  
  
  class TarArchive(BaseArchive):
  
      def __init__(self, file):
          self._archive = tarfile.open(file)
  
      def list(self, *args, **kwargs):
          self._archive.list(*args, **kwargs)
  
      def extract(self, to_path):
          members = self._archive.getmembers()
          leading = self.has_leading_dir(x.name for x in members)
          for member in members:
              name = member.name
              if leading:
                  name = self.split_leading_dir(name)[1]
              filename = os.path.join(to_path, name)
              if member.isdir():
                  if filename and not os.path.exists(filename):
                      os.makedirs(filename)
              else:
                  try:
                      extracted = self._archive.extractfile(member)
                  except (KeyError, AttributeError) as exc:
                      # Some corrupt tar files seem to produce this
                      # (specifically bad symlinks)
                      print("In the tar file %s the member %s is invalid: %s" %
                            (name, member.name, exc))
                  else:
                      dirname = os.path.dirname(filename)
                      if dirname and not os.path.exists(dirname):
                          os.makedirs(dirname)
                      with open(filename, 'wb') as outfile:
                          shutil.copyfileobj(extracted, outfile)
                          self._copy_permissions(member.mode, filename)
                  finally:
                      if extracted:
                          extracted.close()
  
      def close(self):
          self._archive.close()
  
  
  class ZipArchive(BaseArchive):
  
      def __init__(self, file):
          self._archive = zipfile.ZipFile(file)
  
      def list(self, *args, **kwargs):
          self._archive.printdir(*args, **kwargs)
  
      def extract(self, to_path):
          namelist = self._archive.namelist()
          leading = self.has_leading_dir(namelist)
          for name in namelist:
              data = self._archive.read(name)
              info = self._archive.getinfo(name)
              if leading:
                  name = self.split_leading_dir(name)[1]
              filename = os.path.join(to_path, name)
              dirname = os.path.dirname(filename)
              if dirname and not os.path.exists(dirname):
                  os.makedirs(dirname)
              if filename.endswith(('/', '\\')):
                  # A directory
                  if not os.path.exists(filename):
                      os.makedirs(filename)
              else:
                  with open(filename, 'wb') as outfile:
                      outfile.write(data)
                  # Convert ZipInfo.external_attr to mode
                  mode = info.external_attr >> 16
                  self._copy_permissions(mode, filename)
  
      def close(self):
          self._archive.close()
  
  
  extension_map = {
      '.tar': TarArchive,
      '.tar.bz2': TarArchive,
      '.tar.gz': TarArchive,
      '.tgz': TarArchive,
      '.tz2': TarArchive,
      '.zip': ZipArchive,
  }
  