Class FastPath

Lib/importlib/metadata/__init__.py:818–873

Micro-optimized class for searching a root for children. Root is a path on the file system that may contain metadata directories either as natural directories or within a zip file. >>> FastPath('').children() ['...'] FastPath objects are cached and recycled for any given

class FastPath:
    """
    Micro-optimized class for searching a root for children.

    Root is a path on the file system that may contain metadata
    directories either as natural directories or within a zip file.

    >>> FastPath('').children()
    ['...']

    FastPath objects are cached and recycled for any given root.

    >>> FastPath('foobar') is FastPath('foobar')
    True
    """

    @_clear_after_fork  # type: ignore[misc]
    @functools.lru_cache()
    def __new__(cls, root):
        return super().__new__(cls)

    def __init__(self, root):
        self.root = root

    def joinpath(self, child):
        return pathlib.Path(self.root, child)

    def children(self):
        with suppress(Exception):
            return os.listdir(self.root or '.')
        with suppress(Exception):
            return self.zip_children()
        return []

    def zip_children(self):
        # deferred for performance (python/importlib_metadata#502)
        import zipfile

        zip_path = zipfile.Path(self.root)
        names = zip_path.root.namelist()
        self.joinpath = zip_path.joinpath

        return dict.fromkeys(child.split(posixpath.sep, 1)[0] for child in names)

    def search(self, name):
        return self.lookup(self.mtime).search(name)

    @property
    def mtime(self):
        with suppress(OSError):
            return os.stat(self.root).st_mtime
        self.lookup.cache_clear()

    @method_cache
    def lookup(self, mtime):
        return Lookup(self)