caching.py 文件源码

def locking_lru_cache(maxsize=128, typed=False):  # can't implement ignored_keywords because we use python's lru_cache...
    "An lru cache with a lock, to prevent concurrent invocations and allow reusing from cache"

    def deco(func):
        caching_func = lru_cache(maxsize, typed)(func)
        func._main_lock = RLock()
        func._keyed_locks = defaultdict(RLock)

        @wraps(func)
        def inner(*args, **kwargs):
            key = _make_key(args, kwargs, typed=typed)
            with func._main_lock:
                key_lock = func._keyed_locks[key]
            with key_lock:
                return caching_func(*args, **kwargs)

        @wraps(caching_func.cache_clear)
        def clear():
            with func._main_lock:
                return caching_func.cache_clear()

        inner.cache_clear = clear
        return inner

    return deco