Reference Matrix Home Server
1 files changed, 67 insertions, 0 deletions
diff --git a/synapse/util/lockutils.py b/synapse/util/lockutils.py
new file mode 100644
index 0000000000..e4d609d84e
--- /dev/null
+++ b/synapse/util/lockutils.py
@@ -0,0 +1,67 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 matrix.org
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from twisted.internet import defer
+
+import logging
+
+
+logger = logging.getLogger(__name__)
+
+
+class Lock(object):
+
+ def __init__(self, deferred):
+ self._deferred = deferred
+ self.released = False
+
+ def release(self):
+ self.released = True
+ self._deferred.callback(None)
+
+ def __del__(self):
+ if not self.released:
+ logger.critical("Lock was destructed but never released!")
+ self.release()
+
+ def __enter__(self):
+ return self
+
+ def __exit__(self, type, value, traceback):
+ self.release()
+
+
+class LockManager(object):
+ """ Utility class that allows us to lock based on a `key` """
+
+ def __init__(self):
+ self._lock_deferreds = {}
+
+ @defer.inlineCallbacks
+ def lock(self, key):
+ """ Allows us to block until it is our turn.
+ Args:
+ key (str)
+ Returns:
+ Lock
+ """
+ new_deferred = defer.Deferred()
+ old_deferred = self._lock_deferreds.get(key)
+ self._lock_deferreds[key] = new_deferred
+
+ if old_deferred:
+ yield old_deferred
+
+ defer.returnValue(Lock(new_deferred))
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