_compat.py 文件源码

def _make_cached_stream_func(src_func, wrapper_func):
    cache = WeakKeyDictionary()
    def func():
        stream = src_func()
        try:
            rv = cache.get(stream)
        except Exception:
            rv = None
        if rv is not None:
            return rv
        rv = wrapper_func()
        try:
            cache[stream] = rv
        except Exception:
            pass
        return rv
    return func