diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py
index e15f7ee698..4dc3477e89 100644
--- a/synapse/util/caches/expiringcache.py
+++ b/synapse/util/caches/expiringcache.py
@@ -15,40 +15,50 @@
import logging
from collections import OrderedDict
+from typing import Any, Generic, Optional, TypeVar, Union, overload
+
+import attr
+from typing_extensions import Literal
from synapse.config import cache as cache_config
from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.util import Clock
from synapse.util.caches import register_cache
logger = logging.getLogger(__name__)
-SENTINEL = object()
+SENTINEL = object() # type: Any
+
+T = TypeVar("T")
+KT = TypeVar("KT")
+VT = TypeVar("VT")
-class ExpiringCache:
+
+class ExpiringCache(Generic[KT, VT]):
def __init__(
self,
- cache_name,
- clock,
- max_len=0,
- expiry_ms=0,
- reset_expiry_on_get=False,
- iterable=False,
+ cache_name: str,
+ clock: Clock,
+ max_len: int = 0,
+ expiry_ms: int = 0,
+ reset_expiry_on_get: bool = False,
+ iterable: bool = False,
):
"""
Args:
- cache_name (str): Name of this cache, used for logging.
- clock (Clock)
- max_len (int): Max size of dict. If the dict grows larger than this
+ cache_name: Name of this cache, used for logging.
+ clock
+ max_len: Max size of dict. If the dict grows larger than this
then the oldest items get automatically evicted. Default is 0,
which indicates there is no max limit.
- expiry_ms (int): How long before an item is evicted from the cache
+ expiry_ms: How long before an item is evicted from the cache
in milliseconds. Default is 0, indicating items never get
evicted based on time.
- reset_expiry_on_get (bool): If true, will reset the expiry time for
+ reset_expiry_on_get: If true, will reset the expiry time for
an item on access. Defaults to False.
- iterable (bool): If true, the size is calculated by summing the
+ iterable: If true, the size is calculated by summing the
sizes of all entries, rather than the number of entries.
"""
self._cache_name = cache_name
@@ -62,7 +72,7 @@ class ExpiringCache:
self._expiry_ms = expiry_ms
self._reset_expiry_on_get = reset_expiry_on_get
- self._cache = OrderedDict()
+ self._cache = OrderedDict() # type: OrderedDict[KT, _CacheEntry]
self.iterable = iterable
@@ -79,12 +89,12 @@ class ExpiringCache:
self._clock.looping_call(f, self._expiry_ms / 2)
- def __setitem__(self, key, value):
+ def __setitem__(self, key: KT, value: VT) -> None:
now = self._clock.time_msec()
self._cache[key] = _CacheEntry(now, value)
self.evict()
- def evict(self):
+ def evict(self) -> None:
# Evict if there are now too many items
while self._max_size and len(self) > self._max_size:
_key, value = self._cache.popitem(last=False)
@@ -93,7 +103,7 @@ class ExpiringCache:
else:
self.metrics.inc_evictions()
- def __getitem__(self, key):
+ def __getitem__(self, key: KT) -> VT:
try:
entry = self._cache[key]
self.metrics.inc_hits()
@@ -106,7 +116,7 @@ class ExpiringCache:
return entry.value
- def pop(self, key, default=SENTINEL):
+ def pop(self, key: KT, default: T = SENTINEL) -> Union[VT, T]:
"""Removes and returns the value with the given key from the cache.
If the key isn't in the cache then `default` will be returned if
@@ -115,29 +125,40 @@ class ExpiringCache:
Identical functionality to `dict.pop(..)`.
"""
- value = self._cache.pop(key, default)
+ value = self._cache.pop(key, SENTINEL)
+ # The key was not found.
if value is SENTINEL:
- raise KeyError(key)
+ if default is SENTINEL:
+ raise KeyError(key)
+ return default
- return value
+ return value.value
- def __contains__(self, key):
+ def __contains__(self, key: KT) -> bool:
return key in self._cache
- def get(self, key, default=None):
+ @overload
+ def get(self, key: KT, default: Literal[None] = None) -> Optional[VT]:
+ ...
+
+ @overload
+ def get(self, key: KT, default: T) -> Union[VT, T]:
+ ...
+
+ def get(self, key: KT, default: Optional[T] = None) -> Union[VT, Optional[T]]:
try:
return self[key]
except KeyError:
return default
- def setdefault(self, key, value):
+ def setdefault(self, key: KT, value: VT) -> VT:
try:
return self[key]
except KeyError:
self[key] = value
return value
- def _prune_cache(self):
+ def _prune_cache(self) -> None:
if not self._expiry_ms:
# zero expiry time means don't expire. This should never get called
# since we have this check in start too.
@@ -166,7 +187,7 @@ class ExpiringCache:
len(self),
)
- def __len__(self):
+ def __len__(self) -> int:
if self.iterable:
return sum(len(entry.value) for entry in self._cache.values())
else:
@@ -190,9 +211,7 @@ class ExpiringCache:
return False
+@attr.s(slots=True)
class _CacheEntry:
- __slots__ = ["time", "value"]
-
- def __init__(self, time, value):
- self.time = time
- self.value = value
+ time = attr.ib(type=int)
+ value = attr.ib()
|
