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  • Committer: John Arbash Meinel
  • Date: 2007-01-19 18:04:37 UTC
  • Revision ID: john@arbash-meinel.com-20070119180437-12un9b2wea0jgokm
Handle when replacing a key that already exists

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Lines of Context:
cvsps/lru_cache.py
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        :param cleanup: None or a function taking (key, value) to indicate
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                        'value' sohuld be cleaned up.
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        """
 
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        if key in self._cache:
 
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            self._remove(key)
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        self._cache[key] = value
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        self._cleanup[key] = cleanup
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        self._record_access(key)
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        # Make sure the cache is shrunk to the correct size
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        while len(self._cache) > self._max_cache:
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            k = self._queue.popleft()
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            self._refcount[k] -= 1
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            if not self._refcount[k]:
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                del self._refcount[k]
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                cleanup = self._cleanup.pop(k)
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                val = self._cache.pop(k)
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                if cleanup is not None:
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                    cleanup(k, val)
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                del cleanup
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                del val
 
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            self._remove_lru()
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        # If our access queue is too large, clean it up too
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        if len(self._queue) > 4*self._max_cache:
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                len(self._refcount) == sum(self._refcount.itervalues()))
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        gc.collect()
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    def _remove(self, key):
 
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        """Remove an entry, making sure to maintain the invariants."""
 
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        cleanup = self._cleanup.pop(key)
 
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        val = self._cache.pop(key)
 
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        if cleanup is not None:
 
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            cleanup(key, val)
 
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        del cleanup
 
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        del val
 
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    def _remove_lru(self):
 
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        """Remove one entry from the lru, and handle consequences.
 
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        If there are no more references to the lru, then this entry should be
 
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        removed from the cache.
 
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        """
 
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        key = self._queue.popleft()
 
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        self._refcount[key] -= 1
 
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        if not self._refcount[key]:
 
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            del self._refcount[key]
 
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            self._remove(key)
 
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    def clear(self):
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        """Clear out all of the cache."""
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        # Clean up in LRU order
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        while self._cache:
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            k = self._queue.popleft()
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            self._refcount[k] -= 1
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            if not self._refcount[k]:
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                del self._refcount[k]
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                cleanup = self._cleanup.pop(k)
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                val = self._cache.pop(k)
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                if cleanup is not None:
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                    cleanup(k, val)
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                del cleanup
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                del val
 
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            self._remove_lru()