Merge pull request #538 from matrix-org/erikj/fix_lru_cache

Fix LruCache. Make TreeCache track its own size.
This commit is contained in:
Erik Johnston 2016-01-29 11:53:55 +00:00
commit 02a9c3be6c
4 changed files with 57 additions and 8 deletions

View File

@ -37,7 +37,7 @@ class LruCache(object):
"""
def __init__(self, max_size, keylen=1, cache_type=dict):
cache = cache_type()
self.size = 0
self.cache = cache # Used for introspection.
list_root = []
list_root[:] = [list_root, list_root, None, None]
@ -60,7 +60,6 @@ class LruCache(object):
prev_node[NEXT] = node
next_node[PREV] = node
cache[key] = node
self.size += 1
def move_node_to_front(node):
prev_node = node[PREV]
@ -79,7 +78,6 @@ class LruCache(object):
next_node = node[NEXT]
prev_node[NEXT] = next_node
next_node[PREV] = prev_node
self.size -= 1
@synchronized
def cache_get(key, default=None):
@ -98,7 +96,7 @@ class LruCache(object):
node[VALUE] = value
else:
add_node(key, value)
if self.size > max_size:
if len(cache) > max_size:
todelete = list_root[PREV]
delete_node(todelete)
cache.pop(todelete[KEY], None)
@ -110,7 +108,7 @@ class LruCache(object):
return node[VALUE]
else:
add_node(key, value)
if self.size > max_size:
if len(cache) > max_size:
todelete = list_root[PREV]
delete_node(todelete)
cache.pop(todelete[KEY], None)
@ -145,7 +143,7 @@ class LruCache(object):
@synchronized
def cache_len():
return self.size
return len(cache)
@synchronized
def cache_contains(key):

View File

@ -8,6 +8,7 @@ class TreeCache(object):
Keys must be tuples.
"""
def __init__(self):
self.size = 0
self.root = {}
def __setitem__(self, key, value):
@ -20,7 +21,8 @@ class TreeCache(object):
node = self.root
for k in key[:-1]:
node = node.setdefault(k, {})
node[key[-1]] = value
node[key[-1]] = _Entry(value)
self.size += 1
def get(self, key, default=None):
node = self.root
@ -28,9 +30,10 @@ class TreeCache(object):
node = node.get(k, None)
if node is None:
return default
return node.get(key[-1], default)
return node.get(key[-1], _Entry(default)).value
def clear(self):
self.size = 0
self.root = {}
def pop(self, key, default=None):
@ -57,4 +60,33 @@ class TreeCache(object):
break
node_and_keys[i+1][0].pop(k)
popped, cnt = _strip_and_count_entires(popped)
self.size -= cnt
return popped
def __len__(self):
return self.size
class _Entry(object):
__slots__ = ["value"]
def __init__(self, value):
self.value = value
def _strip_and_count_entires(d):
"""Takes an _Entry or dict with leaves of _Entry's, and either returns the
value or a dictionary with _Entry's replaced by their values.
Also returns the count of _Entry's
"""
if isinstance(d, dict):
cnt = 0
for key, value in d.items():
v, n = _strip_and_count_entires(value)
d[key] = v
cnt += n
return d, cnt
else:
return d.value, 1

View File

@ -19,6 +19,7 @@ from .. import unittest
from synapse.util.caches.lrucache import LruCache
from synapse.util.caches.treecache import TreeCache
class LruCacheTestCase(unittest.TestCase):
def test_get_set(self):
@ -72,3 +73,9 @@ class LruCacheTestCase(unittest.TestCase):
self.assertEquals(cache.get(("vehicles", "car")), "vroom")
self.assertEquals(cache.get(("vehicles", "train")), "chuff")
# Man from del_multi say "Yes".
def test_clear(self):
cache = LruCache(1)
cache["key"] = 1
cache.clear()
self.assertEquals(len(cache), 0)

View File

@ -25,6 +25,7 @@ class TreeCacheTestCase(unittest.TestCase):
cache[("b",)] = "B"
self.assertEquals(cache.get(("a",)), "A")
self.assertEquals(cache.get(("b",)), "B")
self.assertEquals(len(cache), 2)
def test_pop_onelevel(self):
cache = TreeCache()
@ -33,6 +34,7 @@ class TreeCacheTestCase(unittest.TestCase):
self.assertEquals(cache.pop(("a",)), "A")
self.assertEquals(cache.pop(("a",)), None)
self.assertEquals(cache.get(("b",)), "B")
self.assertEquals(len(cache), 1)
def test_get_set_twolevel(self):
cache = TreeCache()
@ -42,6 +44,7 @@ class TreeCacheTestCase(unittest.TestCase):
self.assertEquals(cache.get(("a", "a")), "AA")
self.assertEquals(cache.get(("a", "b")), "AB")
self.assertEquals(cache.get(("b", "a")), "BA")
self.assertEquals(len(cache), 3)
def test_pop_twolevel(self):
cache = TreeCache()
@ -53,6 +56,7 @@ class TreeCacheTestCase(unittest.TestCase):
self.assertEquals(cache.get(("a", "b")), "AB")
self.assertEquals(cache.pop(("b", "a")), "BA")
self.assertEquals(cache.pop(("b", "a")), None)
self.assertEquals(len(cache), 1)
def test_pop_mixedlevel(self):
cache = TreeCache()
@ -64,3 +68,11 @@ class TreeCacheTestCase(unittest.TestCase):
self.assertEquals(cache.get(("a", "a")), None)
self.assertEquals(cache.get(("a", "b")), None)
self.assertEquals(cache.get(("b", "a")), "BA")
self.assertEquals(len(cache), 1)
def test_clear(self):
cache = TreeCache()
cache[("a",)] = "A"
cache[("b",)] = "B"
cache.clear()
self.assertEquals(len(cache), 0)