1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
|
class LRUCache:
def __init__(self, capacity, dispose):
self._cache = {}
self._lru = []
self._capacity = capacity
self._dispose = dispose
def __setitem__(self, key, value):
assert key not in self._cache, (
"Unexpected attempt to replace a cached item,"
" without first deleting the old item.")
self._lru.append(key)
while len(self._lru) > self._capacity:
del self[self._lru[0]]
self._cache[key] = value
def __getitem__(self, key):
value = self._cache[key] # raise KeyError if not found
self._lru.remove(key)
self._lru.append(key)
return value
def __delitem__(self, key):
value = self._cache.pop(key) # raise KeyError if not found
self._dispose(value)
self._lru.remove(key)
def __contains__(self, key):
return key in self._cache
def clear(self):
for value in self._cache.values():
self._dispose(value)
self._cache.clear()
# useful for testing
def items(self):
return self._cache.items()
def __len__(self):
return len(self._cache)
|
