posixpath.py 文件源码

def ismount(path):
    """Test whether a path is a mount point"""
    try:
        s1 = os.lstat(path)
    except OSError:
        # It doesn't exist -- so not a mount point. :-)
        return False
    else:
        # A symlink can never be a mount point
        if stat.S_ISLNK(s1.st_mode):
            return False

    if isinstance(path, bytes):
        parent = join(path, b'..')
    else:
        parent = join(path, '..')
    parent = realpath(parent)
    try:
        s2 = os.lstat(parent)
    except OSError:
        return False

    dev1 = s1.st_dev
    dev2 = s2.st_dev
    if dev1 != dev2:
        return True     # path/.. on a different device as path
    ino1 = s1.st_ino
    ino2 = s2.st_ino
    if ino1 == ino2:
        return True     # path/.. is the same i-node as path
    return False


# Expand paths beginning with '~' or '~user'.
# '~' means $HOME; '~user' means that user's home directory.
# If the path doesn't begin with '~', or if the user or $HOME is unknown,
# the path is returned unchanged (leaving error reporting to whatever
# function is called with the expanded path as argument).
# See also module 'glob' for expansion of *, ? and [...] in pathnames.
# (A function should also be defined to do full *sh-style environment
# variable expansion.)