diff options
Diffstat (limited to 'synapse')
| -rw-r--r-- | synapse/util/caches/descriptors.py | 104 |
1 files changed, 0 insertions, 104 deletions
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py index b3c748ef44..75428d19ba 100644 --- a/synapse/util/caches/descriptors.py +++ b/synapse/util/caches/descriptors.py @@ -12,7 +12,6 @@ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. -import enum import functools import inspect import logging @@ -146,109 +145,6 @@ class _CacheDescriptorBase: ) -class _LruCachedFunction(Generic[F]): - cache: LruCache[CacheKey, Any] - __call__: F - - -def lru_cache( - *, max_entries: int = 1000, cache_context: bool = False -) -> Callable[[F], _LruCachedFunction[F]]: - """A method decorator that applies a memoizing cache around the function. - - This is more-or-less a drop-in equivalent to functools.lru_cache, although note - that the signature is slightly different. - - The main differences with functools.lru_cache are: - (a) the size of the cache can be controlled via the cache_factor mechanism - (b) the wrapped function can request a "cache_context" which provides a - callback mechanism to indicate that the result is no longer valid - (c) prometheus metrics are exposed automatically. - - The function should take zero or more arguments, which are used as the key for the - cache. Single-argument functions use that argument as the cache key; otherwise the - arguments are built into a tuple. - - Cached functions can be "chained" (i.e. a cached function can call other cached - functions and get appropriately invalidated when they called caches are - invalidated) by adding a special "cache_context" argument to the function - and passing that as a kwarg to all caches called. For example: - - @lru_cache(cache_context=True) - def foo(self, key, cache_context): - r1 = self.bar1(key, on_invalidate=cache_context.invalidate) - r2 = self.bar2(key, on_invalidate=cache_context.invalidate) - return r1 + r2 - - The wrapped function also has a 'cache' property which offers direct access to the - underlying LruCache. - """ - - def func(orig: F) -> _LruCachedFunction[F]: - desc = LruCacheDescriptor( - orig, - max_entries=max_entries, - cache_context=cache_context, - ) - return cast(_LruCachedFunction[F], desc) - - return func - - -class LruCacheDescriptor(_CacheDescriptorBase): - """Helper for @lru_cache""" - - class _Sentinel(enum.Enum): - sentinel = object() - - def __init__( - self, - orig: Callable[..., Any], - max_entries: int = 1000, - cache_context: bool = False, - ): - super().__init__( - orig, num_args=None, uncached_args=None, cache_context=cache_context - ) - self.max_entries = max_entries - - def __get__(self, obj: Optional[Any], owner: Optional[Type]) -> Callable[..., Any]: - cache: LruCache[CacheKey, Any] = LruCache( - cache_name=self.name, - max_size=self.max_entries, - ) - - get_cache_key = self.cache_key_builder - sentinel = LruCacheDescriptor._Sentinel.sentinel - - @functools.wraps(self.orig) - def _wrapped(*args: Any, **kwargs: Any) -> Any: - invalidate_callback = kwargs.pop("on_invalidate", None) - callbacks = (invalidate_callback,) if invalidate_callback else () - - cache_key = get_cache_key(args, kwargs) - - ret = cache.get(cache_key, default=sentinel, callbacks=callbacks) - if ret != sentinel: - return ret - - # Add our own `cache_context` to argument list if the wrapped function - # has asked for one - if self.add_cache_context: - kwargs["cache_context"] = _CacheContext.get_instance(cache, cache_key) - - ret2 = self.orig(obj, *args, **kwargs) - cache.set(cache_key, ret2, callbacks=callbacks) - - return ret2 - - wrapped = cast(CachedFunction, _wrapped) - wrapped.cache = cache - obj.__dict__[self.name] = wrapped - - return wrapped - - class DeferredCacheDescriptor(_CacheDescriptorBase): """A method decorator that applies a memoizing cache around the function. |