path.py 文件源码

def join(base, *additions):
    '''
    Extends os.path.join so work with s3:// and file:// urls

    This inherits a quirk of os.path.join: if 'addition' is
    an absolute path, path components of base are thrown away.

    'addition' must be an absolute or relative path, not
    a URL.

    `base` and `addition` can use any path separator, but the
    result will always be normalized to os.sep.

    '''
    from urlparse import urlparse, urljoin, ParseResult

    addition = sep.join(additions)

    (scheme, netloc, _, params, query, fragment) = urlparse(addition)
    if any([scheme, netloc, params, query, fragment]):
        raise ValueError('Addition must be an absolute or relative path, not a URL')

    if islocal(base):
        return os.path.join(parse(base).path, addition.replace(sep, os.sep))
    k = parse(base)

    # Call urljoin instead of os.path.join, since it uses '/' instead of
    # os.sep, which is '\' on Windows.
    #
    # Given disparity between os.path.join and urljoin, we prefer the
    # behavior of os.path.join:
    #
    #   >>> os.path.join('foo/bar', 'baz')
    #   'foo/bar/baz'
    #   >>> urlparse.urljoin('foo/bar', 'baz')
    #   'foo/baz'
    #
    # So we add a trailing slash if there is none
    if k.path.endswith(sep):
        s3path = urljoin(k.path, addition)
    else:
        s3path = urljoin(k.path + sep, addition)

    return ParseResult(k.scheme, k.netloc, s3path, k.params, k.query, k.fragment).geturl() # pylint: disable=too-many-function-args,unexpected-keyword-arg