104 lines
3.3 KiB
Python
104 lines
3.3 KiB
Python
# -*- coding: utf-8 -*-
|
|
# Copyright 2015 OpenMarket Ltd
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# 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.
|
|
|
|
from synapse.util.caches.lrucache import LruCache
|
|
from collections import namedtuple
|
|
from . import caches_by_name, cache_counter
|
|
import threading
|
|
import logging
|
|
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
DictionaryEntry = namedtuple("DictionaryEntry", ("full", "value"))
|
|
|
|
|
|
class DictionaryCache(object):
|
|
"""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)
|
|
|
|
self.name = name
|
|
self.sequence = 0
|
|
self.thread = None
|
|
# caches_by_name[name] = self.cache
|
|
|
|
class Sentinel(object):
|
|
__slots__ = []
|
|
|
|
self.sentinel = Sentinel()
|
|
caches_by_name[name] = self.cache
|
|
|
|
def check_thread(self):
|
|
expected_thread = self.thread
|
|
if expected_thread is None:
|
|
self.thread = threading.current_thread()
|
|
else:
|
|
if expected_thread is not threading.current_thread():
|
|
raise ValueError(
|
|
"Cache objects can only be accessed from the main thread"
|
|
)
|
|
|
|
def get(self, key, dict_keys=None):
|
|
entry = self.cache.get(key, self.sentinel)
|
|
if entry is not self.sentinel:
|
|
cache_counter.inc_hits(self.name)
|
|
|
|
if dict_keys is None:
|
|
return DictionaryEntry(entry.full, dict(entry.value))
|
|
else:
|
|
return DictionaryEntry(entry.full, {
|
|
k: entry.value[k]
|
|
for k in dict_keys
|
|
if k in entry.value
|
|
})
|
|
|
|
cache_counter.inc_misses(self.name)
|
|
return DictionaryEntry(False, {})
|
|
|
|
def invalidate(self, key):
|
|
self.check_thread()
|
|
|
|
# Increment the sequence number so that any SELECT statements that
|
|
# raced with the INSERT don't update the cache (SYN-369)
|
|
self.sequence += 1
|
|
self.cache.pop(key, None)
|
|
|
|
def invalidate_all(self):
|
|
self.check_thread()
|
|
self.sequence += 1
|
|
self.cache.clear()
|
|
|
|
def update(self, sequence, key, value, full=False):
|
|
self.check_thread()
|
|
if self.sequence == sequence:
|
|
# Only update the cache if the caches sequence number matches the
|
|
# number that the cache had before the SELECT was started (SYN-369)
|
|
if full:
|
|
self._insert(key, value)
|
|
else:
|
|
self._update_or_insert(key, value)
|
|
|
|
def _update_or_insert(self, key, value):
|
|
entry = self.cache.setdefault(key, DictionaryEntry(False, {}))
|
|
entry.value.update(value)
|
|
|
|
def _insert(self, key, value):
|
|
self.cache[key] = DictionaryEntry(True, value)
|