udocker.py 文件源码

def _relpath(self, path, start):
        """An alternative to os.path.relpath()"""
        if not path:
            raise ValueError("no path specified")
        start_list = posixpath.abspath(start).split(posixpath.sep)
        path_list = posixpath.abspath(path).split(posixpath.sep)
        # Work out how much of the filepath is shared by start and path.
        i = len(posixpath.commonprefix([start_list, path_list]))
        rel_list = [posixpath.pardir] * (len(start_list) - i) + path_list[i:]
        if not rel_list:
            return posixpath.curdir
        return posixpath.join(*rel_list)