From e76d485e29498fce7412423e7a5b6ac6bc287ec3 Mon Sep 17 00:00:00 2001 From: "Paul \"LeoNerd\" Evans" Date: Mon, 23 Feb 2015 15:41:54 +0000 Subject: [PATCH] Allow @cached-wrapped functions to have a prefill method for setting entries --- synapse/storage/_base.py | 23 +++++++++++++++-------- tests/storage/test__base.py | 14 ++++++++++++++ 2 files changed, 29 insertions(+), 8 deletions(-) diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py index 78ba5f25ea..4b1ec687c9 100644 --- a/synapse/storage/_base.py +++ b/synapse/storage/_base.py @@ -48,24 +48,30 @@ def cached(max_entries=1000): The wrapped function has an additional member, a callable called "invalidate". This can be used to remove individual entries from the cache. + + The wrapped function has another additional callable, called "prefill", + which can be used to insert values into the cache specifically, without + calling the calculation function. """ def wrap(orig): cache = {} + def prefill(key, value): + while len(cache) > max_entries: + # TODO(paul): This feels too biased. However, a random index + # would be a bit inefficient, walking the list of keys just + # to ignore most of them? + del cache[cache.keys()[0]] + + cache[key] = value + @defer.inlineCallbacks def wrapped(self, key): if key in cache: defer.returnValue(cache[key]) ret = yield orig(self, key) - - while len(cache) > max_entries: - # TODO(paul): This feels too biased. However, a random index - # would be a bit inefficient, walking the list of keys just - # to ignore most of them? - del cache[cache.keys()[0]] - - cache[key] = ret; + prefill(key, ret) defer.returnValue(ret) def invalidate(key): @@ -73,6 +79,7 @@ def cached(max_entries=1000): del cache[key] wrapped.invalidate = invalidate + wrapped.prefill = prefill return wrapped return wrap diff --git a/tests/storage/test__base.py b/tests/storage/test__base.py index 057f798640..fb306cb784 100644 --- a/tests/storage/test__base.py +++ b/tests/storage/test__base.py @@ -87,3 +87,17 @@ class CacheDecoratorTestCase(unittest.TestCase): self.assertTrue(callcount[0] >= 14, msg="Expected callcount >= 14, got %d" % (callcount[0])) + + @defer.inlineCallbacks + def test_prefill(self): + callcount = [0] + + @cached() + def func(self, key): + callcount[0] += 1 + return key + + func.prefill("foo", 123) + + self.assertEquals((yield func(self, "foo")), 123) + self.assertEquals(callcount[0], 0)