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63 lines
1.7 KiB
63 lines
1.7 KiB
11 years ago
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#!/usr/bin/python
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# -*- coding: utf-8 -*-
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import collections
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import logging
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import heapq
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import time
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class LRUCache(collections.MutableMapping):
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"""This class is not thread safe"""
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def __init__(self, timeout=60, *args, **kwargs):
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self.timeout = timeout
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self.store = {}
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self.time_to_keys = collections.defaultdict(list)
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self.last_visits = []
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self.update(dict(*args, **kwargs)) # use the free update to set keys
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def __getitem__(self, key):
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"O(logm)"
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t = time.time()
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self.time_to_keys[t].append(key)
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heapq.heappush(self.last_visits, t)
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return self.store[key]
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def __setitem__(self, key, value):
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"O(logm)"
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t = time.time()
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self.store[key] = value
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self.time_to_keys[t].append(key)
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heapq.heappush(self.last_visits, t)
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def __delitem__(self, key):
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"O(1)"
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del self.store[key]
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def __iter__(self):
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return iter(self.store)
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def __len__(self):
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return len(self.store)
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def sweep(self):
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"O(m)"
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now = time.time()
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c = 0
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while len(self.last_visits) > 0:
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least = self.last_visits[0]
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if now - least <= self.timeout:
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break
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for key in self.time_to_keys[least]:
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heapq.heappop(self.last_visits)
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if self.store.__contains__(key):
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value = self.store[key]
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if hasattr(value, 'close'):
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value.close()
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del self.store[key]
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c += 1
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del self.time_to_keys[least]
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if c:
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logging.debug('%d keys swept' % c)
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