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Diffstat (limited to 'synapse/util/caches/lrucache.py')
-rw-r--r--synapse/util/caches/lrucache.py63
1 files changed, 38 insertions, 25 deletions
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index 9c4c679175..cf5fbb679c 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -49,7 +49,7 @@ class LruCache(object):
     Can also set callbacks on objects when getting/setting which are fired
     when that key gets invalidated/evicted.
     """
-    def __init__(self, max_size, keylen=1, cache_type=dict):
+    def __init__(self, max_size, keylen=1, cache_type=dict, size_callback=None):
         cache = cache_type()
         self.cache = cache  # Used for introspection.
         list_root = _Node(None, None, None, None)
@@ -58,6 +58,12 @@ class LruCache(object):
 
         lock = threading.Lock()
 
+        def evict():
+            while cache_len() > max_size:
+                todelete = list_root.prev_node
+                delete_node(todelete)
+                cache.pop(todelete.key, None)
+
         def synchronized(f):
             @wraps(f)
             def inner(*args, **kwargs):
@@ -66,6 +72,16 @@ class LruCache(object):
 
             return inner
 
+        cached_cache_len = [0]
+        if size_callback is not None:
+            def cache_len():
+                return cached_cache_len[0]
+        else:
+            def cache_len():
+                return len(cache)
+
+        self.len = synchronized(cache_len)
+
         def add_node(key, value, callbacks=set()):
             prev_node = list_root
             next_node = prev_node.next_node
@@ -74,6 +90,9 @@ class LruCache(object):
             next_node.prev_node = node
             cache[key] = node
 
+            if size_callback:
+                cached_cache_len[0] += size_callback(node.value)
+
         def move_node_to_front(node):
             prev_node = node.prev_node
             next_node = node.next_node
@@ -92,23 +111,25 @@ class LruCache(object):
             prev_node.next_node = next_node
             next_node.prev_node = prev_node
 
+            if size_callback:
+                cached_cache_len[0] -= size_callback(node.value)
+
             for cb in node.callbacks:
                 cb()
             node.callbacks.clear()
 
         @synchronized
-        def cache_get(key, default=None, callback=None):
+        def cache_get(key, default=None, callbacks=[]):
             node = cache.get(key, None)
             if node is not None:
                 move_node_to_front(node)
-                if callback:
-                    node.callbacks.add(callback)
+                node.callbacks.update(callbacks)
                 return node.value
             else:
                 return default
 
         @synchronized
-        def cache_set(key, value, callback=None):
+        def cache_set(key, value, callbacks=[]):
             node = cache.get(key, None)
             if node is not None:
                 if value != node.value:
@@ -116,21 +137,18 @@ class LruCache(object):
                         cb()
                     node.callbacks.clear()
 
-                if callback:
-                    node.callbacks.add(callback)
+                    if size_callback:
+                        cached_cache_len[0] -= size_callback(node.value)
+                        cached_cache_len[0] += size_callback(value)
+
+                node.callbacks.update(callbacks)
 
                 move_node_to_front(node)
                 node.value = value
             else:
-                if callback:
-                    callbacks = set([callback])
-                else:
-                    callbacks = set()
-                add_node(key, value, callbacks)
-                if len(cache) > max_size:
-                    todelete = list_root.prev_node
-                    delete_node(todelete)
-                    cache.pop(todelete.key, None)
+                add_node(key, value, set(callbacks))
+
+            evict()
 
         @synchronized
         def cache_set_default(key, value):
@@ -139,10 +157,7 @@ class LruCache(object):
                 return node.value
             else:
                 add_node(key, value)
-                if len(cache) > max_size:
-                    todelete = list_root.prev_node
-                    delete_node(todelete)
-                    cache.pop(todelete.key, None)
+                evict()
                 return value
 
         @synchronized
@@ -174,10 +189,8 @@ class LruCache(object):
                 for cb in node.callbacks:
                     cb()
             cache.clear()
-
-        @synchronized
-        def cache_len():
-            return len(cache)
+            if size_callback:
+                cached_cache_len[0] = 0
 
         @synchronized
         def cache_contains(key):
@@ -190,7 +203,7 @@ class LruCache(object):
         self.pop = cache_pop
         if cache_type is TreeCache:
             self.del_multi = cache_del_multi
-        self.len = cache_len
+        self.len = synchronized(cache_len)
         self.contains = cache_contains
         self.clear = cache_clear