From 71b11f557d919573afeb33895487d8eae47a0abe Mon Sep 17 00:00:00 2001
From: "Justin Clark-Casey (justincc)" <jjustincc@googlemail.com>
Date: Thu, 19 Jan 2012 23:09:16 +0000
Subject: [PATCH] Allow a viewer UDP image request retry to trigger another
 asset fetch if an existing fetch hasn't responded before a timeout.

This is to stop a high priority image/texture request from blocking the entire download queue if its asset fetch got dropped for some reason.
---
 .../Region/ClientStack/Linden/UDP/J2KImage.cs | 32 +++++++++++++++++--
 .../ClientStack/Linden/UDP/LLImageManager.cs  |  6 ++--
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/OpenSim/Region/ClientStack/Linden/UDP/J2KImage.cs b/OpenSim/Region/ClientStack/Linden/UDP/J2KImage.cs
index 474d2a5476..cf622ca00e 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/J2KImage.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/J2KImage.cs
@@ -45,6 +45,15 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         private const int IMAGE_PACKET_SIZE = 1000;
         private const int FIRST_PACKET_SIZE = 600;
 
+        /// <summary>
+        /// If we've requested an asset but not received it in this ticks timeframe, then allow a duplicate
+        /// request from the client to trigger a fresh asset request.
+        /// </summary>
+        /// <remarks>
+        /// There are 10,000 ticks in a millisecond
+        /// </remarks>
+        private const int ASSET_REQUEST_TIMEOUT = 100000000;
+
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
         public uint LastSequence;
@@ -57,8 +66,22 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         public UUID AgentID;
         public IInventoryAccessModule InventoryAccessModule;
         private OpenJPEG.J2KLayerInfo[] m_layers;
+
+        /// <summary>
+        /// Has this request decoded the asset data?
+        /// </summary>
         public bool IsDecoded { get; private set; }
+
+        /// <summary>
+        /// Has this request received the required asset data?
+        /// </summary>
         public bool HasAsset { get; private set; }
+
+        /// <summary>
+        /// Time in milliseconds at which the asset was requested.
+        /// </summary>
+        public long AssetRequestTime { get; private set; }
+
         public C5.IPriorityQueueHandle<J2KImage> PriorityQueueHandle;
 
         private uint m_currentPacket;
@@ -123,10 +146,15 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         {
             if (!HasAsset)
             {
-                if (!m_assetRequested)
+                if (!m_assetRequested || DateTime.UtcNow.Ticks > AssetRequestTime + ASSET_REQUEST_TIMEOUT)
                 {
+//                    m_log.DebugFormat(
+//                        "[J2KIMAGE]: Requesting asset {0} from request in packet {1}, already requested? {2}, due to timeout? {3}",
+//                        TextureID, LastSequence, m_assetRequested, DateTime.UtcNow.Ticks > AssetRequestTime + ASSET_REQUEST_TIMEOUT);
+
                     m_assetRequested = true;
-//                    m_log.DebugFormat("[J2KIMAGE]: Requesting asset {0}", TextureID);
+                    AssetRequestTime = DateTime.UtcNow.Ticks;
+
                     AssetService.Get(TextureID.ToString(), this, AssetReceived);
                 }
             }
diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLImageManager.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLImageManager.cs
index a48251f9c0..073c357d1a 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLImageManager.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLImageManager.cs
@@ -101,9 +101,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
                 // Do a linear search for this texture download
                 lock (m_syncRoot)
-                {
                     m_priorityQueue.Find(delegate(J2KImage img) { return img.TextureID == newRequest.RequestedAssetID; }, out imgrequest);
-                }
 
                 if (imgrequest != null)
                 {
@@ -124,8 +122,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 //                            "[LL IMAGE MANAGER]: Received duplicate of existing request for {0}, start packet {1} from {2}",
 //                            newRequest.RequestedAssetID, newRequest.PacketNumber, m_client.Name);
 
-                        //m_log.DebugFormat("[TEX]: (UPD) ID={0}: D={1}, S={2}, P={3}",
-                        //    newRequest.RequestedAssetID, newRequest.DiscardLevel, newRequest.PacketNumber, newRequest.Priority);
+//                        m_log.DebugFormat("[TEX]: (UPD) ID={0}: D={1}, S={2}, P={3}",
+//                            newRequest.RequestedAssetID, newRequest.DiscardLevel, newRequest.PacketNumber, newRequest.Priority);
 
                         //Check the packet sequence to make sure this isn't older than
                         //one we've already received