* Copied LocklessQueue.cs into OpenSim.Framework and added the .Count property and .Clear() method

* Changed the way the QueueEmpty callback is fired. It will be fired asynchronously as soon as an empty queue is detected (this can happen immediately following a dequeue), and will not be fired again until at least one packet is dequeued from that queue. This will give callbacks advanced notice of an empty queue and prevent callbacks from stacking up while the queue is empty
* Added LLUDPClient.IsConnected checks in several places to prevent unwanted network activity after a client disconnects
* Prevent LLClientView.Close() from being called twice every disconnect
* Removed the packet resend limit and improved the client timeout check

1 files changed, 41 insertions, 9 deletions

diff --git a/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs b/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs
index e5b2594..b27d8d6 100644
--- a/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs
+++ b/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs
@@ -80,7 +80,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// <summary>Packets we have sent that need to be ACKed by the client</summary>
         public readonly UnackedPacketCollection NeedAcks = new UnackedPacketCollection();
         /// <summary>ACKs that are queued up, waiting to be sent to the client</summary>
-        public readonly LocklessQueue<uint> PendingAcks = new LocklessQueue<uint>();
+        public readonly OpenSim.Framework.LocklessQueue<uint> PendingAcks = new OpenSim.Framework.LocklessQueue<uint>();
 
         /// <summary>Current packet sequence number</summary>
         public int CurrentSequence;
@@ -127,13 +127,16 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// <summary>Throttle rate defaults and limits</summary>
         private readonly ThrottleRates defaultThrottleRates;
         /// <summary>Outgoing queues for throttled packets</summary>
-        private readonly LocklessQueue<OutgoingPacket>[] packetOutboxes = new LocklessQueue<OutgoingPacket>[THROTTLE_CATEGORY_COUNT];
+        private readonly OpenSim.Framework.LocklessQueue<OutgoingPacket>[] packetOutboxes = new OpenSim.Framework.LocklessQueue<OutgoingPacket>[THROTTLE_CATEGORY_COUNT];
         /// <summary>A container that can hold one packet for each outbox, used to store
         /// dequeued packets that are being held for throttling</summary>
         private readonly OutgoingPacket[] nextPackets = new OutgoingPacket[THROTTLE_CATEGORY_COUNT];
         /// <summary>An optimization to store the length of dequeued packets being held
         /// for throttling. This avoids expensive calls to Packet.Length</summary>
         private readonly int[] nextPacketLengths = new int[THROTTLE_CATEGORY_COUNT];
+        /// <summary>Flags to prevent queue empty callbacks from repeatedly firing
+        /// before the callbacks have a chance to put packets in the queue</summary>
+        private readonly bool[] queueEmptySent = new bool[THROTTLE_CATEGORY_COUNT];
         /// <summary>A reference to the LLUDPServer that is managing this client</summary>
         private readonly LLUDPServer udpServer;
 
@@ -156,7 +159,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             defaultThrottleRates = rates;
 
             for (int i = 0; i < THROTTLE_CATEGORY_COUNT; i++)
-                packetOutboxes[i] = new LocklessQueue<OutgoingPacket>();
+                packetOutboxes[i] = new OpenSim.Framework.LocklessQueue<OutgoingPacket>();
 
             throttle = new TokenBucket(parentThrottle, 0, 0);
             throttleCategories = new TokenBucket[THROTTLE_CATEGORY_COUNT];
@@ -182,6 +185,14 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         public void Shutdown()
         {
             IsConnected = false;
+            NeedAcks.Clear();
+            for (int i = 0; i < THROTTLE_CATEGORY_COUNT; i++)
+            {
+                packetOutboxes[i].Clear();
+                nextPackets[i] = null;
+            }
+            OnPacketStats = null;
+            OnQueueEmpty = null;
         }
 
         /// <summary>
@@ -322,7 +333,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
             if (category >= 0 && category < packetOutboxes.Length)
             {
-                LocklessQueue<OutgoingPacket> queue = packetOutboxes[category];
+                OpenSim.Framework.LocklessQueue<OutgoingPacket> queue = packetOutboxes[category];
                 TokenBucket bucket = throttleCategories[category];
 
                 if (throttleCategories[category].RemoveTokens(packet.Buffer.DataLength))
@@ -354,7 +365,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         public bool DequeueOutgoing()
         {
             OutgoingPacket packet;
-            LocklessQueue<OutgoingPacket> queue;
+            OpenSim.Framework.LocklessQueue<OutgoingPacket> queue;
             TokenBucket bucket;
             bool packetSent = false;
 
@@ -382,6 +393,10 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     queue = packetOutboxes[i];
                     if (queue.Dequeue(out packet))
                     {
+                        // Reset the flag for firing this queue's OnQueueEmpty callback
+                        // now that we have dequeued a packet
+                        queueEmptySent[i] = false;
+
                         // A packet was pulled off the queue. See if we have
                         // enough tokens in the bucket to send it out
                         if (bucket.RemoveTokens(packet.Buffer.DataLength))
@@ -397,13 +412,18 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                             nextPackets[i] = packet;
                             nextPacketLengths[i] = packet.Buffer.DataLength;
                         }
+
+                        // If the queue is empty after this dequeue, fire the queue
+                        // empty callback now so it has a chance to fill before we 
+                        // get back here
+                        if (queue.Count == 0)
+                            FireQueueEmpty(i);
                     }
                     else
                     {
                         // No packets in this queue. Fire the queue empty callback
-                        QueueEmpty callback = OnQueueEmpty;
-                        if (callback != null)
-                            callback((ThrottleOutPacketType)i);
+                        // if it has not been called recently
+                        FireQueueEmpty(i);
                     }
                 }
             }
@@ -432,8 +452,20 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
             // Always round retransmission timeout up to two seconds
             RTO = Math.Max(2000, (int)(SRTT + Math.Max(G, K * RTTVAR)));
-            //Logger.Debug("Setting agent " + this.Agent.FullName + "'s RTO to " + RTO + "ms with an RTTVAR of " +
+            //m_log.Debug("[LLUDPCLIENT]: Setting agent " + this.Agent.FullName + "'s RTO to " + RTO + "ms with an RTTVAR of " +
             //    RTTVAR + " based on new RTT of " + r + "ms");
         }
+
+        private void FireQueueEmpty(int queueIndex)
+        {
+            if (!queueEmptySent[queueIndex])
+            {
+                queueEmptySent[queueIndex] = true;
+
+                QueueEmpty callback = OnQueueEmpty;
+                if (callback != null)
+                    Util.FireAndForget(delegate(object o) { callback((ThrottleOutPacketType)(int)o); }, queueIndex);
+            }
+        }
     }
 }