Python sys.path() Examples

def _warn_unsafe_extraction_path(path):
        """
        If the default extraction path is overridden and set to an insecure
        location, such as /tmp, it opens up an opportunity for an attacker to
        replace an extracted file with an unauthorized payload. Warn the user
        if a known insecure location is used.

        See Distribute #375 for more details.
        """
        if os.name == 'nt' and not path.startswith(os.environ['windir']):
            # On Windows, permissions are generally restrictive by default
            #  and temp directories are not writable by other users, so
            #  bypass the warning.
            return
        mode = os.stat(path).st_mode
        if mode & stat.S_IWOTH or mode & stat.S_IWGRP:
            msg = ("%s is writable by group/others and vulnerable to attack "
                "when "
                "used with get_resource_filename. Consider a more secure "
                "location (set with .set_extraction_path or the "
                "PYTHON_EGG_CACHE environment variable)." % path)
            warnings.warn(msg, UserWarning) 

def pip_execute(*args, **kwargs):
    """Overriden pip_execute() to stop sys.path being changed.

    The act of importing main from the pip module seems to cause add wheels
    from the /usr/share/python-wheels which are installed by various tools.
    This function ensures that sys.path remains the same after the call is
    executed.
    """
    try:
        _path = sys.path
        try:
            from pip import main as _pip_execute
        except ImportError:
            apt_update()
            apt_install('python-pip')
            from pip import main as _pip_execute
        _pip_execute(*args, **kwargs)
    finally:
        sys.path = _path 

def removeduppaths():
    """ Remove duplicate entries from sys.path along with making them
    absolute"""
    # This ensures that the initial path provided by the interpreter contains
    # only absolute pathnames, even if we're running from the build directory.
    L = []
    known_paths = set()
    for dir in sys.path:
        # Filter out duplicate paths (on case-insensitive file systems also
        # if they only differ in case); turn relative paths into absolute
        # paths.
        dir, dircase = makepath(dir)
        if not dircase in known_paths:
            L.append(dir)
            known_paths.add(dircase)
    sys.path[:] = L
    return known_paths

# XXX This should not be part of site.py, since it is needed even when
# using the -S option for Python.  See http://www.python.org/sf/586680 

def shared_locations(self):
        """
        A dictionary of shared locations whose keys are in the set 'prefix',
        'purelib', 'platlib', 'scripts', 'headers', 'data' and 'namespace'.
        The corresponding value is the absolute path of that category for
        this distribution, and takes into account any paths selected by the
        user at installation time (e.g. via command-line arguments). In the
        case of the 'namespace' key, this would be a list of absolute paths
        for the roots of namespace packages in this distribution.

        The first time this property is accessed, the relevant information is
        read from the SHARED file in the .dist-info directory.
        """
        result = {}
        shared_path = os.path.join(self.path, 'SHARED')
        if os.path.isfile(shared_path):
            with codecs.open(shared_path, 'r', encoding='utf-8') as f:
                lines = f.read().splitlines()
            for line in lines:
                key, value = line.split('=', 1)
                if key == 'namespace':
                    result.setdefault(key, []).append(value)
                else:
                    result[key] = value
        return result 

def _by_version_descending(names):
    """
    Given a list of filenames, return them in descending order
    by version number.

    >>> names = 'bar', 'foo', 'Python-2.7.10.egg', 'Python-2.7.2.egg'
    >>> _by_version_descending(names)
    ['Python-2.7.10.egg', 'Python-2.7.2.egg', 'foo', 'bar']
    >>> names = 'Setuptools-1.2.3b1.egg', 'Setuptools-1.2.3.egg'
    >>> _by_version_descending(names)
    ['Setuptools-1.2.3.egg', 'Setuptools-1.2.3b1.egg']
    >>> names = 'Setuptools-1.2.3b1.egg', 'Setuptools-1.2.3.post1.egg'
    >>> _by_version_descending(names)
    ['Setuptools-1.2.3.post1.egg', 'Setuptools-1.2.3b1.egg']
    """
    def _by_version(name):
        """
        Parse each component of the filename
        """
        name, ext = os.path.splitext(name)
        parts = itertools.chain(name.split('-'), [ext])
        return [packaging.version.parse(part) for part in parts]

    return sorted(names, key=_by_version, reverse=True) 

def run_script(self, script_name, namespace):
        script = 'scripts/' + script_name
        if not self.has_metadata(script):
            raise ResolutionError("No script named %r" % script_name)
        script_text = self.get_metadata(script).replace('\r\n', '\n')
        script_text = script_text.replace('\r', '\n')
        script_filename = self._fn(self.egg_info, script)
        namespace['__file__'] = script_filename
        if os.path.exists(script_filename):
            source = open(script_filename).read()
            code = compile(source, script_filename, 'exec')
            exec(code, namespace, namespace)
        else:
            from linecache import cache
            cache[script_filename] = (
                len(script_text), 0, script_text.split('\n'), script_filename
            )
            script_code = compile(script_text, script_filename, 'exec')
            exec(script_code, namespace, namespace) 

def zipdir(path, zipn):
    for root, dirs, files in os.walk(path):
        for file in files:
            zipn.write(os.path.join(root, file)) 

def cachedir(self):
        """Path to workflow's cache directory.

        The cache directory is a subdirectory of Alfred's own cache directory
        in ``~/Library/Caches``. The full path is:

        ``~/Library/Caches/com.runningwithcrayons.Alfred-X/Workflow Data/<bundle id>``

        ``Alfred-X`` may be ``Alfred-2`` or ``Alfred-3``.

        :returns: full path to workflow's cache directory
        :rtype: ``unicode``

        """
        if self.alfred_env.get('workflow_cache'):
            dirpath = self.alfred_env.get('workflow_cache')

        else:
            dirpath = self._default_cachedir

        return self._create(dirpath) 

def datadir(self):
        """Path to workflow's data directory.

        The data directory is a subdirectory of Alfred's own data directory in
        ``~/Library/Application Support``. The full path is:

        ``~/Library/Application Support/Alfred 2/Workflow Data/<bundle id>``

        :returns: full path to workflow data directory
        :rtype: ``unicode``

        """
        if self.alfred_env.get('workflow_data'):
            dirpath = self.alfred_env.get('workflow_data')

        else:
            dirpath = self._default_datadir

        return self._create(dirpath) 

def _delete_directory_contents(self, dirpath, filter_func):
        """Delete all files in a directory.

        :param dirpath: path to directory to clear
        :type dirpath: ``unicode`` or ``str``
        :param filter_func function to determine whether a file shall be
            deleted or not.
        :type filter_func ``callable``

        """
        if os.path.exists(dirpath):
            for filename in os.listdir(dirpath):
                if not filter_func(filename):
                    continue
                path = os.path.join(dirpath, filename)
                if os.path.isdir(path):
                    shutil.rmtree(path)
                else:
                    os.unlink(path)
                self.logger.debug('Deleted : %r', path) 

def logic(data):
    # ????????
    #print data
    f1 = open('/tmp/test.txt','a')
    f1.write(data)
    f1.write('\n')
    f1.close()
    data = json.loads(data)
    print type(data)
    mounts = data["MOUNT"]
    netifaces = data["NET"]
    for netif in netifaces:
        if netif["status"] == "up":
            ip = netif["ip"]
    #print netifaces['ip']
    for mount in mounts:
        Mount_point= mount['path']
        use_rate=mount['used_rate']
        if use_rate > '70':
            send_mail(recvmail_conf['addr'],"mount point"+Mount_point ,used_rate)
    return("OK") 

def addsitedir(sitedir, known_paths=None):
    """Add 'sitedir' argument to sys.path if missing and handle .pth files in
    'sitedir'"""
    if known_paths is None:
        known_paths = _init_pathinfo()
        reset = 1
    else:
        reset = 0
    sitedir, sitedircase = makepath(sitedir)
    if not sitedircase in known_paths:
        sys.path.append(sitedir)        # Add path component
    try:
        names = os.listdir(sitedir)
    except os.error:
        return
    names.sort()
    for name in names:
        if name.endswith(os.extsep + "pth"):
            addpackage(sitedir, name, known_paths)
    if reset:
        known_paths = None
    return known_paths 

def __setup(self):
        if self.__lines:
            return
        data = None
        for dir in self.__dirs:
            for filename in self.__files:
                filename = os.path.join(dir, filename)
                try:
                    fp = open(filename, "rU")
                    data = fp.read()
                    fp.close()
                    break
                except IOError:
                    pass
            if data:
                break
        if not data:
            data = self.__data
        self.__lines = data.split('\n')
        self.__linecnt = len(self.__lines) 

def setcopyright():
    """Set 'copyright' and 'credits' in __builtin__"""
    builtins.copyright = _Printer("copyright", sys.copyright)
    if _is_jython:
        builtins.credits = _Printer(
            "credits",
            "Jython is maintained by the Jython developers (www.jython.org).")
    elif _is_pypy:
        builtins.credits = _Printer(
            "credits",
            "PyPy is maintained by the PyPy developers: http://pypy.org/")
    else:
        builtins.credits = _Printer("credits", """\
    Thanks to CWI, CNRI, BeOpen.com, Zope Corporation and a cast of thousands
    for supporting Python development.  See www.python.org for more information.""")
    here = os.path.dirname(os.__file__)
    builtins.license = _Printer(
        "license", "See http://www.python.org/%.3s/license.html" % sys.version,
        ["LICENSE.txt", "LICENSE"],
        [os.path.join(here, os.pardir), here, os.curdir]) 

def __init__(self, path=None, include_egg=False):
        """
        Create an instance from a path, optionally including legacy (distutils/
        setuptools/distribute) distributions.
        :param path: The path to use, as a list of directories. If not specified,
                     sys.path is used.
        :param include_egg: If True, this instance will look for and return legacy
                            distributions as well as those based on PEP 376.
        """
        if path is None:
            path = sys.path
        self.path = path
        self._include_dist = True
        self._include_egg = include_egg

        self._cache = _Cache()
        self._cache_egg = _Cache()
        self._cache_enabled = True
        self._scheme = get_scheme('default') 

def _generate_cache(self):
        """
        Scan the path for distributions and populate the cache with
        those that are found.
        """
        gen_dist = not self._cache.generated
        gen_egg = self._include_egg and not self._cache_egg.generated
        if gen_dist or gen_egg:
            for dist in self._yield_distributions():
                if isinstance(dist, InstalledDistribution):
                    self._cache.add(dist)
                else:
                    self._cache_egg.add(dist)

            if gen_dist:
                self._cache.generated = True
            if gen_egg:
                self._cache_egg.generated = True 

def get_distributions(self):
        """
        Provides an iterator that looks for distributions and returns
        :class:`InstalledDistribution` or
        :class:`EggInfoDistribution` instances for each one of them.

        :rtype: iterator of :class:`InstalledDistribution` and
                :class:`EggInfoDistribution` instances
        """
        if not self._cache_enabled:
            for dist in self._yield_distributions():
                yield dist
        else:
            self._generate_cache()

            for dist in self._cache.path.values():
                yield dist

            if self._include_egg:
                for dist in self._cache_egg.path.values():
                    yield dist 

def get_distribution(self, name):
        """
        Looks for a named distribution on the path.

        This function only returns the first result found, as no more than one
        value is expected. If nothing is found, ``None`` is returned.

        :rtype: :class:`InstalledDistribution`, :class:`EggInfoDistribution`
                or ``None``
        """
        result = None
        name = name.lower()
        if not self._cache_enabled:
            for dist in self._yield_distributions():
                if dist.key == name:
                    result = dist
                    break
        else:
            self._generate_cache()

            if name in self._cache.name:
                result = self._cache.name[name][0]
            elif self._include_egg and name in self._cache_egg.name:
                result = self._cache_egg.name[name][0]
        return result 

def _get_records(self):
        """
        Get the list of installed files for the distribution
        :return: A list of tuples of path, hash and size. Note that hash and
                 size might be ``None`` for some entries. The path is exactly
                 as stored in the file (which is as in PEP 376).
        """
        results = []
        r = self.get_distinfo_resource('RECORD')
        with contextlib.closing(r.as_stream()) as stream:
            with CSVReader(stream=stream) as record_reader:
                # Base location is parent dir of .dist-info dir
                #base_location = os.path.dirname(self.path)
                #base_location = os.path.abspath(base_location)
                for row in record_reader:
                    missing = [None for i in range(len(row), 3)]
                    path, checksum, size = row + missing
                    #if not os.path.isabs(path):
                    #    path = path.replace('/', os.sep)
                    #    path = os.path.join(base_location, path)
                    results.append((path, checksum, size))
        return results 

def get_resource_path(self, relative_path):
        """
        NOTE: This API may change in the future.

        Return the absolute path to a resource file with the given relative
        path.

        :param relative_path: The path, relative to .dist-info, of the resource
                              of interest.
        :return: The absolute path where the resource is to be found.
        """
        r = self.get_distinfo_resource('RESOURCES')
        with contextlib.closing(r.as_stream()) as stream:
            with CSVReader(stream=stream) as resources_reader:
                for relative, destination in resources_reader:
                    if relative == relative_path:
                        return destination
        raise KeyError('no resource file with relative path %r '
                       'is installed' % relative_path) 

def write_shared_locations(self, paths, dry_run=False):
        """
        Write shared location information to the SHARED file in .dist-info.
        :param paths: A dictionary as described in the documentation for
        :meth:`shared_locations`.
        :param dry_run: If True, the action is logged but no file is actually
                        written.
        :return: The path of the file written to.
        """
        shared_path = os.path.join(self.path, 'SHARED')
        logger.info('creating %s', shared_path)
        if dry_run:
            return None
        lines = []
        for key in ('prefix', 'lib', 'headers', 'scripts', 'data'):
            path = paths[key]
            if os.path.isdir(paths[key]):
                lines.append('%s=%s' % (key,  path))
        for ns in paths.get('namespace', ()):
            lines.append('namespace=%s' % ns)

        with codecs.open(shared_path, 'w', encoding='utf-8') as f:
            f.write('\n'.join(lines))
        return shared_path 

def __init__(self, path, env=None):
        def set_name_and_version(s, n, v):
            s.name = n
            s.key = n.lower()   # for case-insensitive comparisons
            s.version = v

        self.path = path
        self.dist_path = env
        if env and env._cache_enabled and path in env._cache_egg.path:
            metadata = env._cache_egg.path[path].metadata
            set_name_and_version(self, metadata.name, metadata.version)
        else:
            metadata = self._get_metadata(path)

            # Need to be set before caching
            set_name_and_version(self, metadata.name, metadata.version)

            if env and env._cache_enabled:
                env._cache_egg.add(self)
        super(EggInfoDistribution, self).__init__(metadata, path, env) 

def check_installed_files(self):
        """
        Checks that the hashes and sizes of the files in ``RECORD`` are
        matched by the files themselves. Returns a (possibly empty) list of
        mismatches. Each entry in the mismatch list will be a tuple consisting
        of the path, 'exists', 'size' or 'hash' according to what didn't match
        (existence is checked first, then size, then hash), the expected
        value and the actual value.
        """
        mismatches = []
        record_path = os.path.join(self.path, 'installed-files.txt')
        if os.path.exists(record_path):
            for path, _, _ in self.list_installed_files():
                if path == record_path:
                    continue
                if not os.path.exists(path):
                    mismatches.append((path, 'exists', True, False))
        return mismatches 

def _build_from_requirements(cls, req_spec):
        """
        Build a working set from a requirement spec. Rewrites sys.path.
        """
        # try it without defaults already on sys.path
        # by starting with an empty path
        ws = cls([])
        reqs = parse_requirements(req_spec)
        dists = ws.resolve(reqs, Environment())
        for dist in dists:
            ws.add(dist)

        # add any missing entries from sys.path
        for entry in sys.path:
            if entry not in ws.entries:
                ws.add_entry(entry)

        # then copy back to sys.path
        sys.path[:] = ws.entries
        return ws 

def __iter__(self):
        """Yield distributions for non-duplicate projects in the working set

        The yield order is the order in which the items' path entries were
        added to the working set.
        """
        seen = {}
        for item in self.entries:
            if item not in self.entry_keys:
                # workaround a cache issue
                continue

            for key in self.entry_keys[item]:
                if key not in seen:
                    seen[key] = 1
                    yield self.by_key[key] 

def __init__(self, search_path=None, platform=get_supported_platform(),
            python=PY_MAJOR):
        """Snapshot distributions available on a search path

        Any distributions found on `search_path` are added to the environment.
        `search_path` should be a sequence of ``sys.path`` items.  If not
        supplied, ``sys.path`` is used.

        `platform` is an optional string specifying the name of the platform
        that platform-specific distributions must be compatible with.  If
        unspecified, it defaults to the current platform.  `python` is an
        optional string naming the desired version of Python (e.g. ``'3.3'``);
        it defaults to the current version.

        You may explicitly set `platform` (and/or `python`) to ``None`` if you
        wish to map *all* distributions, not just those compatible with the
        running platform or Python version.
        """
        self._distmap = {}
        self.platform = platform
        self.python = python
        self.scan(search_path) 

def get_cache_path(self, archive_name, names=()):
        """Return absolute location in cache for `archive_name` and `names`

        The parent directory of the resulting path will be created if it does
        not already exist.  `archive_name` should be the base filename of the
        enclosing egg (which may not be the name of the enclosing zipfile!),
        including its ".egg" extension.  `names`, if provided, should be a
        sequence of path name parts "under" the egg's extraction location.

        This method should only be called by resource providers that need to
        obtain an extraction location, and only for names they intend to
        extract, as it tracks the generated names for possible cleanup later.
        """
        extract_path = self.extraction_path or get_default_cache()
        target_path = os.path.join(extract_path, archive_name + '-tmp', *names)
        try:
            _bypass_ensure_directory(target_path)
        except:
            self.extraction_error()

        self._warn_unsafe_extraction_path(extract_path)

        self.cached_files[target_path] = 1
        return target_path 

def set_extraction_path(self, path):
        """Set the base path where resources will be extracted to, if needed.

        If you do not call this routine before any extractions take place, the
        path defaults to the return value of ``get_default_cache()``.  (Which
        is based on the ``PYTHON_EGG_CACHE`` environment variable, with various
        platform-specific fallbacks.  See that routine's documentation for more
        details.)

        Resources are extracted to subdirectories of this path based upon
        information given by the ``IResourceProvider``.  You may set this to a
        temporary directory, but then you must call ``cleanup_resources()`` to
        delete the extracted files when done.  There is no guarantee that
        ``cleanup_resources()`` will be able to remove all extracted files.

        (Note: you may not change the extraction path for a given resource
        manager once resources have been extracted, unless you first call
        ``cleanup_resources()``.)
        """
        if self.cached_files:
            raise ValueError(
                "Can't change extraction path, files already extracted"
            )

        self.extraction_path = path 

def find_eggs_in_zip(importer, path_item, only=False):
    """
    Find eggs in zip files; possibly multiple nested eggs.
    """
    if importer.archive.endswith('.whl'):
        # wheels are not supported with this finder
        # they don't have PKG-INFO metadata, and won't ever contain eggs
        return
    metadata = EggMetadata(importer)
    if metadata.has_metadata('PKG-INFO'):
        yield Distribution.from_filename(path_item, metadata=metadata)
    if only:
        # don't yield nested distros
        return
    for subitem in metadata.resource_listdir('/'):
        if _is_unpacked_egg(subitem):
            subpath = os.path.join(path_item, subitem)
            for dist in find_eggs_in_zip(zipimport.zipimporter(subpath), subpath):
                yield dist 

def register_namespace_handler(importer_type, namespace_handler):
    """Register `namespace_handler` to declare namespace packages

    `importer_type` is the type or class of a PEP 302 "Importer" (sys.path item
    handler), and `namespace_handler` is a callable like this::

        def namespace_handler(importer, path_entry, moduleName, module):
            # return a path_entry to use for child packages

    Namespace handlers are only called if the importer object has already
    agreed that it can handle the relevant path item, and they should only
    return a subpath if the module __path__ does not already contain an
    equivalent subpath.  For an example namespace handler, see
    ``pkg_resources.file_ns_handler``.
    """
    _namespace_handlers[importer_type] = namespace_handler 

def check_version_conflict(self):
        if self.key == 'setuptools':
            # ignore the inevitable setuptools self-conflicts  :(
            return

        nsp = dict.fromkeys(self._get_metadata('namespace_packages.txt'))
        loc = normalize_path(self.location)
        for modname in self._get_metadata('top_level.txt'):
            if (modname not in sys.modules or modname in nsp
                    or modname in _namespace_packages):
                continue
            if modname in ('pkg_resources', 'setuptools', 'site'):
                continue
            fn = getattr(sys.modules[modname], '__file__', None)
            if fn and (normalize_path(fn).startswith(loc) or
                       fn.startswith(self.location)):
                continue
            issue_warning(
                "Module %s was already imported from %s, but %s is being added"
                " to sys.path" % (modname, fn, self.location),
            ) 

def setup_py(self):
        assert self.source_dir, "No source dir for %s" % self
        try:
            import setuptools  # noqa
        except ImportError:
            if get_installed_version('setuptools') is None:
                add_msg = "Please install setuptools."
            else:
                add_msg = traceback.format_exc()
            # Setuptools is not available
            raise InstallationError(
                "Could not import setuptools which is required to "
                "install from a source distribution.\n%s" % add_msg
            )

        setup_py = os.path.join(self.setup_py_dir, 'setup.py')

        # Python2 __file__ should not be unicode
        if six.PY2 and isinstance(setup_py, six.text_type):
            setup_py = setup_py.encode(sys.getfilesystemencoding())

        return setup_py 

def _build_from_requirements(cls, req_spec):
        """
        Build a working set from a requirement spec. Rewrites sys.path.
        """
        # try it without defaults already on sys.path
        # by starting with an empty path
        ws = cls([])
        reqs = parse_requirements(req_spec)
        dists = ws.resolve(reqs, Environment())
        for dist in dists:
            ws.add(dist)

        # add any missing entries from sys.path
        for entry in sys.path:
            if entry not in ws.entries:
                ws.add_entry(entry)

        # then copy back to sys.path
        sys.path[:] = ws.entries
        return ws 

def __iter__(self):
        """Yield distributions for non-duplicate projects in the working set

        The yield order is the order in which the items' path entries were
        added to the working set.
        """
        seen = {}
        for item in self.entries:
            if item not in self.entry_keys:
                # workaround a cache issue
                continue

            for key in self.entry_keys[item]:
                if key not in seen:
                    seen[key] = 1
                    yield self.by_key[key] 

def get_cache_path(self, archive_name, names=()):
        """Return absolute location in cache for `archive_name` and `names`

        The parent directory of the resulting path will be created if it does
        not already exist.  `archive_name` should be the base filename of the
        enclosing egg (which may not be the name of the enclosing zipfile!),
        including its ".egg" extension.  `names`, if provided, should be a
        sequence of path name parts "under" the egg's extraction location.

        This method should only be called by resource providers that need to
        obtain an extraction location, and only for names they intend to
        extract, as it tracks the generated names for possible cleanup later.
        """
        extract_path = self.extraction_path or get_default_cache()
        target_path = os.path.join(extract_path, archive_name + '-tmp', *names)
        try:
            _bypass_ensure_directory(target_path)
        except:
            self.extraction_error()

        self._warn_unsafe_extraction_path(extract_path)

        self.cached_files[target_path] = 1
        return target_path 

def _warn_unsafe_extraction_path(path):
        """
        If the default extraction path is overridden and set to an insecure
        location, such as /tmp, it opens up an opportunity for an attacker to
        replace an extracted file with an unauthorized payload. Warn the user
        if a known insecure location is used.

        See Distribute #375 for more details.
        """
        if os.name == 'nt' and not path.startswith(os.environ['windir']):
            # On Windows, permissions are generally restrictive by default
            #  and temp directories are not writable by other users, so
            #  bypass the warning.
            return
        mode = os.stat(path).st_mode
        if mode & stat.S_IWOTH or mode & stat.S_IWGRP:
            msg = ("%s is writable by group/others and vulnerable to attack "
                "when "
                "used with get_resource_filename. Consider a more secure "
                "location (set with .set_extraction_path or the "
                "PYTHON_EGG_CACHE environment variable)." % path)
            warnings.warn(msg, UserWarning) 

def set_extraction_path(self, path):
        """Set the base path where resources will be extracted to, if needed.

        If you do not call this routine before any extractions take place, the
        path defaults to the return value of ``get_default_cache()``.  (Which
        is based on the ``PYTHON_EGG_CACHE`` environment variable, with various
        platform-specific fallbacks.  See that routine's documentation for more
        details.)

        Resources are extracted to subdirectories of this path based upon
        information given by the ``IResourceProvider``.  You may set this to a
        temporary directory, but then you must call ``cleanup_resources()`` to
        delete the extracted files when done.  There is no guarantee that
        ``cleanup_resources()`` will be able to remove all extracted files.

        (Note: you may not change the extraction path for a given resource
        manager once resources have been extracted, unless you first call
        ``cleanup_resources()``.)
        """
        if self.cached_files:
            raise ValueError(
                "Can't change extraction path, files already extracted"
            )

        self.extraction_path = path 

def build(cls, path):
        """
        Build a dictionary similar to the zipimport directory
        caches, except instead of tuples, store ZipInfo objects.

        Use a platform-specific path separator (os.sep) for the path keys
        for compatibility with pypy on Windows.
        """
        with ContextualZipFile(path) as zfile:
            items = (
                (
                    name.replace('/', os.sep),
                    zfile.getinfo(name),
                )
                for name in zfile.namelist()
            )
            return dict(items) 

def _index(self):
        try:
            return self._dirindex
        except AttributeError:
            ind = {}
            for path in self.zipinfo:
                parts = path.split(os.sep)
                while parts:
                    parent = os.sep.join(parts[:-1])
                    if parent in ind:
                        ind[parent].append(parts[-1])
                        break
                    else:
                        ind[parent] = [parts.pop()]
            self._dirindex = ind
            return ind 

def _by_version_descending(names):
    """
    Given a list of filenames, return them in descending order
    by version number.

    >>> names = 'bar', 'foo', 'Python-2.7.10.egg', 'Python-2.7.2.egg'
    >>> _by_version_descending(names)
    ['Python-2.7.10.egg', 'Python-2.7.2.egg', 'foo', 'bar']
    >>> names = 'Setuptools-1.2.3b1.egg', 'Setuptools-1.2.3.egg'
    >>> _by_version_descending(names)
    ['Setuptools-1.2.3.egg', 'Setuptools-1.2.3b1.egg']
    >>> names = 'Setuptools-1.2.3b1.egg', 'Setuptools-1.2.3.post1.egg'
    >>> _by_version_descending(names)
    ['Setuptools-1.2.3.post1.egg', 'Setuptools-1.2.3b1.egg']
    """
    def _by_version(name):
        """
        Parse each component of the filename
        """
        name, ext = os.path.splitext(name)
        parts = itertools.chain(name.split('-'), [ext])
        return [packaging.version.parse(part) for part in parts]

    return sorted(names, key=_by_version, reverse=True) 

def _handle_ns(packageName, path_item):
    """Ensure that named package includes a subpath of path_item (if needed)"""

    importer = get_importer(path_item)
    if importer is None:
        return None
    loader = importer.find_module(packageName)
    if loader is None:
        return None
    module = sys.modules.get(packageName)
    if module is None:
        module = sys.modules[packageName] = types.ModuleType(packageName)
        module.__path__ = []
        _set_parent_ns(packageName)
    elif not hasattr(module, '__path__'):
        raise TypeError("Not a package:", packageName)
    handler = _find_adapter(_namespace_handlers, importer)
    subpath = handler(importer, path_item, packageName, module)
    if subpath is not None:
        path = module.__path__
        path.append(subpath)
        loader.load_module(packageName)
        _rebuild_mod_path(path, packageName, module)
    return subpath 

def pip_install(package, fatal=False, upgrade=False, venv=None, **options):
    """Install a python package"""
    if venv:
        venv_python = os.path.join(venv, 'bin/pip')
        command = [venv_python, "install"]
    else:
        command = ["install"]

    available_options = ('proxy', 'src', 'log', 'index-url', )
    for option in parse_options(options, available_options):
        command.append(option)

    if upgrade:
        command.append('--upgrade')

    if isinstance(package, list):
        command.extend(package)
    else:
        command.append(package)

    log("Installing {} package with options: {}".format(package,
                                                        command))
    if venv:
        subprocess.check_call(command)
    else:
        pip_execute(command) 

def pip_create_virtualenv(path=None):
    """Create an isolated Python environment."""
    apt_install('python-virtualenv')

    if path:
        venv_path = path
    else:
        venv_path = os.path.join(charm_dir(), 'venv')

    if not os.path.exists(venv_path):
        subprocess.check_call(['virtualenv', venv_path]) 

def get_cwd():
    path = os.getcwd()
    path = path + '>'
    return path 

def append_slash_if_dir(p):
    if p and os.path.isdir(p) and p[-1] != os.sep:
        return p + os.sep
    else:
        return p 

def find_path(text, line, begidx, endidx, \
                dir_only=False, files_only=False, exe_only=False,\
                py_only=False, uploads=False, all_dir=False):
    cur_dir = os.getcwd()
    before_arg = line.rfind(" ", 0, begidx)
    if before_arg == -1:
        return # arg not found

    fixed = line[before_arg+1:begidx]  # fixed portion of the arg
    arg = line[before_arg+1:endidx]

    if uploads:
        os.chdir(uploads_path)
    pattern = arg + '*'

    completions = []
    for path in glob.glob(pattern):
        if dir_only:
            if os.path.isdir(path):
                path = append_slash_if_dir(path)
                completions.append(path.replace(fixed, "", 1))
        elif files_only:
            if not os.path.isdir(path):
                completions.append(path.replace(fixed, "", 1))
        elif exe_only:
            if not os.path.isdir(path):
                if path.endswith('.exe') or path.endswith('.py'):
                    completions.append(path.replace(fixed, "", 1))
        elif py_only:
            if not os.path.isdir(path):
                if path.endswith('.py'):
                    completions.append(path.replace(fixed, "", 1))
        elif all_dir:
            if os.path.isdir(path):
                path = append_slash_if_dir(path)
            completions.append(path.replace(fixed, "", 1))

    os.chdir(cur_dir)
    return completions 

def st_logger(resp,log_path,log_name,verbose=True):
    if no_error(resp):
        i = 1
        log = os.path.join(log_path,'{}.log'.format(log_name))
        while os.path.exists(log):
            new_log_name = '{} ({}).log'.format(log_name,i)
            log = os.path.join(log_path,new_log_name)
            i += 1
        if verbose: st_print("[+] Output has been written to {}\n".format(log))
        with open(log,'w') as l:
            l.write(resp)

#http://stackoverflow.com/questions/2828953/silence-the-stdout-of-a-function-in-python-without-trashing-sys-stdout-and-resto 

def atomic_writer(file_path, mode):
    """Atomic file writer.

    :param file_path: path of file to write to.
    :type file_path: ``unicode``
    :param mode: sames as for `func:open`
    :type mode: string

    .. versionadded:: 1.12

    Context manager that ensures the file is only written if the write
    succeeds. The data is first written to a temporary file.

    """
    temp_suffix = '.aw.temp'
    temp_file_path = file_path + temp_suffix
    with open(temp_file_path, mode) as file_obj:
        try:
            yield file_obj
            os.rename(temp_file_path, file_path)
        finally:
            try:
                os.remove(temp_file_path)
            except (OSError, IOError):
                pass 

def __init__(self, filepath, defaults=None):
        """Create new :class:`Settings` object."""
        super(Settings, self).__init__()
        self._filepath = filepath
        self._nosave = False
        self._original = {}
        if os.path.exists(self._filepath):
            self._load()
        elif defaults:
            for key, val in defaults.items():
                self[key] = val
            self.save()  # save default settings 

def _default_datadir(self):
        """Alfred 2's default data directory."""
        return os.path.join(os.path.expanduser(
            '~/Library/Application Support/Alfred 2/Workflow Data/'),
            self.bundleid)