Towards recovery-aware delivery tag management in models

Author: michaelklishin

projects/client/RabbitMQ.Client/src/client/impl/AutorecoveringConnection.cs

@@ -404,7 +404,10 @@ public void UnregisterModel(AutorecoveringModel model)
 
         protected IModel CreateNonRecoveringModel()
         {
-            return m_delegate.CreateModel();
+            ISession session  = m_delegate.CreateSession();
+            IFullModel result = (IFullModel)(new RecoveryAwareModel(session));
+            result._Private_ChannelOpen("");
+            return result;
         }
 
         public IList<ShutdownReportEntry> ShutdownReport

projects/client/RabbitMQ.Client/src/client/impl/ModelBase.cs

@@ -587,13 +587,13 @@ public MethodBase ModelRpc(MethodBase method, ContentHeaderBase header, byte[] b
 
         public abstract bool DispatchAsynchronous(Command cmd);
 
-        public void HandleBasicDeliver(string consumerTag,
-                                       ulong deliveryTag,
-                                       bool redelivered,
-                                       string exchange,
-                                       string routingKey,
-                                       IBasicProperties basicProperties,
-                                       byte[] body)
+        public virtual void HandleBasicDeliver(string consumerTag,
+                                               ulong deliveryTag,
+                                               bool redelivered,
+                                               string exchange,
+                                               string routingKey,
+                                               IBasicProperties basicProperties,
+                                               byte[] body)
         {
             IBasicConsumer consumer;
             lock (m_consumers)

projects/client/RabbitMQ.Client/src/client/impl/RecoveryAwareModel.cs

@@ -0,0 +1,110 @@
+// This source code is dual-licensed under the Apache License, version
+// 2.0, and the Mozilla Public License, version 1.1.
+//
+// The APL v2.0:
+//
+//---------------------------------------------------------------------------
+//   Copyright (C) 2007-2014 GoPivotal, Inc.
+//
+//   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.
+//---------------------------------------------------------------------------
+//
+// The MPL v1.1:
+//
+//---------------------------------------------------------------------------
+//  The contents of this file are subject to the Mozilla Public License
+//  Version 1.1 (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.mozilla.org/MPL/
+//
+//  Software distributed under the License is distributed on an "AS IS"
+//  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+//  the License for the specific language governing rights and
+//  limitations under the License.
+//
+//  The Original Code is RabbitMQ.
+//
+//  The Initial Developer of the Original Code is GoPivotal, Inc.
+//  Copyright (c) 2007-2014 GoPivotal, Inc.  All rights reserved.
+//---------------------------------------------------------------------------
+
+using System;
+
+using RabbitMQ.Client.Framing.Impl;
+
+namespace RabbitMQ.Client.Impl
+{
+    public class RecoveryAwareModel : Model, IFullModel, IRecoverable
+    {
+        private ulong maxSeenDeliveryTag = 0;
+        private ulong activeDeliveryTagOffset = 0;
+
+        public RecoveryAwareModel(ISession session) : base(session) {}
+
+        public override void HandleBasicDeliver(string consumerTag,
+                                                ulong deliveryTag,
+                                                bool redelivered,
+                                                string exchange,
+                                                string routingKey,
+                                                IBasicProperties basicProperties,
+                                                byte[] body)
+        {
+            if(deliveryTag > maxSeenDeliveryTag)
+            {
+                maxSeenDeliveryTag = deliveryTag;
+            }
+
+            base.HandleBasicDeliver(consumerTag,
+                                    OffsetDeliveryTag(deliveryTag),
+                                    redelivered,
+                                    exchange,
+                                    routingKey,
+                                    basicProperties,
+                                    body);
+        }
+
+        public override void BasicAck(ulong deliveryTag,
+                                      bool multiple) {
+            var realTag = deliveryTag - activeDeliveryTagOffset;
+            if(realTag > 0)
+            {
+                base.BasicAck(deliveryTag, multiple);
+            }
+        }
+
+        public override void BasicReject(ulong deliveryTag,
+                                         bool requeue) {
+            var realTag = deliveryTag - activeDeliveryTagOffset;
+            if(realTag > 0)
+            {
+                base.BasicReject(deliveryTag, requeue);
+            }
+        }
+
+        public override void BasicNack(ulong deliveryTag,
+                                       bool multiple,
+                                       bool requeue) {
+            var realTag = deliveryTag - activeDeliveryTagOffset;
+            if(realTag > 0)
+            {
+                base.BasicNack(deliveryTag, multiple, requeue);
+            }
+        }
+
+
+        protected ulong OffsetDeliveryTag(ulong deliveryTag)
+        {
+            return deliveryTag + this.activeDeliveryTagOffset;
+        }
+    }
+}