diff options
Diffstat (limited to 'synapse/util/caches/dictionary_cache.py')
| -rw-r--r-- | synapse/util/caches/dictionary_cache.py | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/synapse/util/caches/dictionary_cache.py b/synapse/util/caches/dictionary_cache.py index 8b426c005b..588d2d49f2 100644 --- a/synapse/util/caches/dictionary_cache.py +++ b/synapse/util/caches/dictionary_cache.py @@ -12,10 +12,11 @@ # 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 logging import threading from collections import namedtuple +from typing import Any from synapse.util.caches.lrucache import LruCache @@ -38,23 +39,26 @@ class DictionaryEntry(namedtuple("DictionaryEntry", ("full", "known_absent", "va return len(self.value) +class _Sentinel(enum.Enum): + # defining a sentinel in this way allows mypy to correctly handle the + # type of a dictionary lookup. + sentinel = object() + + class DictionaryCache: """Caches key -> dictionary lookups, supporting caching partial dicts, i.e. fetching a subset of dictionary keys for a particular key. """ def __init__(self, name, max_entries=1000): - self.cache = LruCache(max_size=max_entries, cache_name=name, size_callback=len) + self.cache = LruCache( + max_size=max_entries, cache_name=name, size_callback=len + ) # type: LruCache[Any, DictionaryEntry] self.name = name self.sequence = 0 self.thread = None - class Sentinel: - __slots__ = [] - - self.sentinel = Sentinel() - def check_thread(self): expected_thread = self.thread if expected_thread is None: @@ -76,8 +80,8 @@ class DictionaryCache: Returns: DictionaryEntry """ - entry = self.cache.get(key, self.sentinel) - if entry is not self.sentinel: + entry = self.cache.get(key, _Sentinel.sentinel) + if entry is not _Sentinel.sentinel: if dict_keys is None: return DictionaryEntry( entry.full, entry.known_absent, dict(entry.value) |