1 files changed, 55 insertions, 0 deletions
diff --git a/qpid/dotnet/Qpid.Client/Client/Failover/FailoverSupport.cs b/qpid/dotnet/Qpid.Client/Client/Failover/FailoverSupport.cs
new file mode 100644
index 0000000000..afa5301f39
--- /dev/null
+++ b/qpid/dotnet/Qpid.Client/Client/Failover/FailoverSupport.cs
@@ -0,0 +1,55 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ *
+ */
+using log4net;
+
+namespace Apache.Qpid.Client.Failover
+{
+    public abstract class FailoverSupport
+    {
+        private static readonly ILog _log = LogManager.GetLogger(typeof(FailoverSupport));
+
+        public object execute(AMQConnection con)
+        {
+            // We wait until we are not in the middle of failover before acquiring the mutex and then proceeding.
+            // Any method that can potentially block for any reason should use this class so that deadlock will not
+            // occur. The FailoverException is propagated by the AMQProtocolHandler to any listeners (e.g. frame listeners)
+            // that might be causing a block. When that happens, the exception is caught here and the mutex is released
+            // before waiting for the failover to complete (either successfully or unsuccessfully).
+            while (true)
+            {
+                con.ProtocolListener.BlockUntilNotFailingOver();
+                lock (con.FailoverMutex)
+                {
+                    try
+                    {
+                        return operation();
+                    }
+                    catch (FailoverException e)
+                    {
+                        _log.Info("Failover exception caught during operation", e);
+                    }
+                }
+            }
+        }
+
+        protected abstract object operation();
+    }
+}