langhelpers.py 文件源码

def decorator(target):
    """A signature-matching decorator factory."""

    def decorate(fn):
        if not inspect.isfunction(fn):
            raise Exception("not a decoratable function")
        spec = compat.inspect_getfullargspec(fn)
        names = tuple(spec[0]) + spec[1:3] + (fn.__name__,)
        targ_name, fn_name = _unique_symbols(names, 'target', 'fn')

        metadata = dict(target=targ_name, fn=fn_name)
        metadata.update(format_argspec_plus(spec, grouped=False))
        metadata['name'] = fn.__name__
        code = """\
def %(name)s(%(args)s):
    return %(target)s(%(fn)s, %(apply_kw)s)
""" % metadata
        decorated = _exec_code_in_env(code,
                                      {targ_name: target, fn_name: fn},
                                      fn.__name__)
        decorated.__defaults__ = getattr(fn, 'im_func', fn).__defaults__
        decorated.__wrapped__ = fn
        return update_wrapper(decorated, fn)
    return update_wrapper(decorate, target)