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by Martin Pool
Merge from aaron: |
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# Copyright (C) 2005 by Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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from trace import mutter |
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from bzrlib.store import ImmutableStore |
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class CachedStore: |
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"""A store that caches data locally, to avoid repeated downloads.
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The precacache method should be used to avoid server round-trips for
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every piece of data.
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"""
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def __init__(self, store, cache_dir): |
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self.source_store = store |
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self.cache_store = ImmutableStore(cache_dir) |
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def __getitem__(self, id): |
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mutter("Cache add %s" % id) |
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if id not in self.cache_store: |
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self.cache_store.add(self.source_store[id], id) |
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return self.cache_store[id] |
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def prefetch(self, ids): |
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"""Copy a series of ids into the cache, before they are used.
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For remote stores that support pipelining or async downloads, this can
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increase speed considerably.
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"""
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mutter("Prefetch of ids %s" % ",".join(ids)) |
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self.cache_store.copy_multi(self.source_store, ids) |