65 lines
1.8 KiB
Python
65 lines
1.8 KiB
Python
# Copyright 2025 Google LLC
|
|
#
|
|
# 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
|
|
#
|
|
# https://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 collections import OrderedDict
|
|
|
|
|
|
class LRUCache(dict):
|
|
def __init__(self, maxsize):
|
|
super().__init__()
|
|
self._order = OrderedDict()
|
|
self.maxsize = maxsize
|
|
|
|
def clear(self):
|
|
super().clear()
|
|
self._order.clear()
|
|
|
|
def get(self, key, default=None):
|
|
try:
|
|
value = super().__getitem__(key)
|
|
self._update(key)
|
|
return value
|
|
except KeyError:
|
|
return default
|
|
|
|
def __getitem__(self, key):
|
|
value = super().__getitem__(key)
|
|
self._update(key)
|
|
return value
|
|
|
|
def __setitem__(self, key, value):
|
|
maxsize = self.maxsize
|
|
if maxsize <= 0:
|
|
return
|
|
if key not in self:
|
|
while len(self) >= maxsize:
|
|
self.popitem()
|
|
super().__setitem__(key, value)
|
|
self._update(key)
|
|
|
|
def __delitem__(self, key):
|
|
super().__delitem__(key)
|
|
del self._order[key]
|
|
|
|
def popitem(self):
|
|
"""Remove and return the least recently used key-value pair."""
|
|
key, _ = self._order.popitem(last=False)
|
|
return key, super().pop(key)
|
|
|
|
def _update(self, key):
|
|
try:
|
|
self._order.move_to_end(key)
|
|
except KeyError:
|
|
self._order[key] = None
|