borg/attic/lrucache.py

43 lines
1.1 KiB
Python

class LRUCache(dict):
def __init__(self, capacity):
super(LRUCache, self).__init__()
self._lru = []
self._capacity = capacity
def __setitem__(self, key, value):
try:
self._lru.remove(key)
except ValueError:
pass
self._lru.append(key)
while len(self._lru) > self._capacity:
del self[self._lru[0]]
return super(LRUCache, self).__setitem__(key, value)
def __getitem__(self, key):
try:
self._lru.remove(key)
self._lru.append(key)
except ValueError:
pass
return super(LRUCache, self).__getitem__(key)
def __delitem__(self, key):
try:
self._lru.remove(key)
except ValueError:
pass
return super(LRUCache, self).__delitem__(key)
def pop(self, key, default=None):
try:
self._lru.remove(key)
except ValueError:
pass
return super(LRUCache, self).pop(key, default)
def _not_implemented(self, *args, **kw):
raise NotImplementedError
popitem = setdefault = update = _not_implemented