Ticket #21012: locmem.diff

django/core/cache/backends/locmem.py

@@ -1 +1 @@
 "Thread-safe in-memory cache backend."
 
 import time
+import threading
 try:
     from django.utils.six.moves import cPickle as pickle
 except ImportError:
@@ -12 +13 @@
 
 # Global in-memory store of cache data. Keyed by name, to provide
 # multiple named local memory caches.
-_caches = {}
-_expire_info = {}
-_locks = {}
+_cache_info = {}
+_cache_info_lock = threading.Lock()
 
 
 class LocMemCache(BaseCache):
     def __init__(self, name, params):
         BaseCache.__init__(self, params)
-        self._cache = _caches.setdefault(name, {})
-        self._expire_info = _expire_info.setdefault(name, {})
-        self._lock = _locks.setdefault(name, RWLock())
+        if name in _cache_info:
+            cache_info = _cache_info[name]
+        else:
+            with _cache_info_lock:
+                cache_info = _cache_info.setdefault(name, ({}, {}, RWLock()))
+        self._cache, self._expire_info, self._lock = cache_info
 
     def add(self, key, value, timeout=DEFAULT_TIMEOUT, version=None):
         key = self.make_key(key, version=version)