* Adds IAssetService.GetCached() to allow asset fetching from the local cache only

* Adds GetTextureModule that implements the "GetTexture" capability, aka HTTP texture fetching. This is a significantly optimized path that does not require any server-side JPEG2000 decoding, texture priority queue, or UDP file transfer
* Sanity check for null reference in LLClientView.RefreshGroupMembership()

OpenSim/Region/ClientStack/LindenUDP/LLClientView.cs

@@ -11302,9 +11302,12 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
                 m_groupPowers.Clear();
 
-                for (int i = 0; i < GroupMembership.Length; i++)
+                if (GroupMembership != null)
                 {
-                    m_groupPowers[GroupMembership[i].GroupID] = GroupMembership[i].GroupPowers;
+                    for (int i = 0; i < GroupMembership.Length; i++)
+                    {
+                        m_groupPowers[GroupMembership[i].GroupID] = GroupMembership[i].GroupPowers;
+                    }
                 }
             }
         }

OpenSim/Region/CoreModules/Asset/FlotsamAssetCache.cs

@@ -406,6 +406,11 @@ namespace Flotsam.RegionModules.AssetCache
             return asset;
         }
 
+        public AssetBase GetCached(string id)
+        {
+            return Get(id);
+        }
+
         public void Expire(string id)
         {
             if (m_LogLevel >= 2)

OpenSim/Region/CoreModules/Avatar/Assets/GetTextureModule.cs

@@ -0,0 +1,220 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using System.Collections;
+using System.Collections.Specialized;
+using System.Reflection;
+using System.IO;
+using System.Web;
+using log4net;
+using Nini.Config;
+using OpenMetaverse;
+using OpenMetaverse.StructuredData;
+using OpenSim.Framework;
+using OpenSim.Framework.Servers;
+using OpenSim.Framework.Servers.HttpServer;
+using OpenSim.Region.Framework.Interfaces;
+using OpenSim.Region.Framework.Scenes;
+using OpenSim.Services.Interfaces;
+using Caps = OpenSim.Framework.Capabilities.Caps;
+
+namespace OpenSim.Region.CoreModules.Avatar.ObjectCaps
+{
+    #region Stream Handler
+
+    public delegate byte[] StreamHandlerCallback(string path, Stream request, OSHttpRequest httpRequest, OSHttpResponse httpResponse);
+
+    public class StreamHandler : BaseStreamHandler
+    {
+        StreamHandlerCallback m_callback;
+
+        public StreamHandler(string httpMethod, string path, StreamHandlerCallback callback)
+            : base(httpMethod, path)
+        {
+            m_callback = callback;
+        }
+
+        public override byte[] Handle(string path, Stream request, OSHttpRequest httpRequest, OSHttpResponse httpResponse)
+        {
+            return m_callback(path, request, httpRequest, httpResponse);
+        }
+    }
+
+    #endregion Stream Handler
+
+    public class GetTextureModule : IRegionModule
+    {
+        private static readonly ILog m_log =
+            LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+        private Scene m_scene;
+        private IAssetService m_assetService;
+
+        #region IRegionModule Members
+
+        public void Initialise(Scene pScene, IConfigSource pSource)
+        {
+            m_scene = pScene;
+        }
+
+        public void PostInitialise()
+        {
+            m_assetService = m_scene.RequestModuleInterface<IAssetService>();
+            m_scene.EventManager.OnRegisterCaps += RegisterCaps;
+        }
+
+        public void Close() { }
+
+        public string Name { get { return "GetTextureModule"; } }
+        public bool IsSharedModule { get { return false; } }
+
+        public void RegisterCaps(UUID agentID, Caps caps)
+        {
+            UUID capID = UUID.Random();
+
+            m_log.Info("[GETTEXTURE]: /CAPS/" + capID);
+            caps.RegisterHandler("GetTexture", new StreamHandler("GET", "/CAPS/" + capID, ProcessGetTexture));
+        }
+
+        #endregion
+
+        private byte[] ProcessGetTexture(string path, Stream request, OSHttpRequest httpRequest, OSHttpResponse httpResponse)
+        {
+            // TODO: Change this to a config option
+            const string REDIRECT_URL = null;
+
+            // Try to parse the texture ID from the request URL
+            NameValueCollection query = HttpUtility.ParseQueryString(httpRequest.Url.Query);
+            string textureStr = query.GetOne("texture_id");
+
+            if (m_assetService == null)
+            {
+                m_log.Error("[GETTEXTURE]: Cannot fetch texture " + textureStr + " without an asset service");
+                httpResponse.StatusCode = (int)System.Net.HttpStatusCode.NotFound;
+                return null;
+            }
+
+            UUID textureID;
+            if (!String.IsNullOrEmpty(textureStr) && UUID.TryParse(textureStr, out textureID))
+            {
+                AssetBase texture;
+
+                if (!String.IsNullOrEmpty(REDIRECT_URL))
+                {
+                    // Only try to fetch locally cached textures. Misses are redirected
+                    texture = m_assetService.GetCached(textureID.ToString());
+
+                    if (texture != null)
+                    {
+                        SendTexture(httpRequest, httpResponse, texture);
+                    }
+                    else
+                    {
+                        string textureUrl = REDIRECT_URL + textureID.ToString();
+                        m_log.Debug("[GETTEXTURE]: Redirecting texture request to " + textureUrl);
+                        httpResponse.RedirectLocation = textureUrl;
+                    }
+                }
+                else
+                {
+                    // Fetch locally or remotely. Misses return a 404
+                    texture = m_assetService.Get(textureID.ToString());
+
+                    if (texture != null)
+                    {
+                        SendTexture(httpRequest, httpResponse, texture);
+                    }
+                    else
+                    {
+                        m_log.Warn("[GETTEXTURE]: Texture " + textureID + " not found");
+                        httpResponse.StatusCode = (int)System.Net.HttpStatusCode.NotFound;
+                    }
+                }
+            }
+            else
+            {
+                m_log.Warn("[GETTEXTURE]: Failed to parse a texture_id from GetTexture request: " + httpRequest.Url);
+            }
+
+            httpResponse.Send();
+            return null;
+        }
+
+        private void SendTexture(OSHttpRequest request, OSHttpResponse response, AssetBase texture)
+        {
+            string range = request.Headers.GetOne("Range");
+            if (!String.IsNullOrEmpty(range))
+            {
+                // Range request
+                int start, end;
+                if (TryParseRange(range, out start, out end))
+                {
+                    end = Utils.Clamp(end, 1, texture.Data.Length);
+                    start = Utils.Clamp(start, 0, end - 1);
+
+                    m_log.Debug("Serving " + start + " to " + end + " of " + texture.Data.Length + " bytes for texture " + texture.ID);
+
+                    if (end - start < texture.Data.Length)
+                        response.StatusCode = (int)System.Net.HttpStatusCode.PartialContent;
+
+                    response.ContentLength = end - start;
+                    response.ContentType = texture.Metadata.ContentType;
+
+                    response.Body.Write(texture.Data, start, end - start);
+                }
+                else
+                {
+                    m_log.Warn("Malformed Range header: " + range);
+                    response.StatusCode = (int)System.Net.HttpStatusCode.BadRequest;
+                }
+            }
+            else
+            {
+                // Full content request
+                response.ContentLength = texture.Data.Length;
+                response.ContentType = texture.Metadata.ContentType;
+                response.Body.Write(texture.Data, 0, texture.Data.Length);
+            }
+        }
+
+        private bool TryParseRange(string header, out int start, out int end)
+        {
+            if (header.StartsWith("bytes="))
+            {
+                string[] rangeValues = header.Substring(6).Split('-');
+                if (rangeValues.Length == 2)
+                {
+                    if (Int32.TryParse(rangeValues[0], out start) && Int32.TryParse(rangeValues[1], out end))
+                        return true;
+                }
+            }
+
+            start = end = 0;
+            return false;
+        }
+    }
+}

OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/HGAssetBroker.cs

@@ -229,6 +229,14 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Asset
             return asset;
         }
 
+        public AssetBase GetCached(string id)
+        {
+            if (m_Cache != null)
+                return m_Cache.Get(id);
+
+            return null;
+        }
+
         public AssetMetadata GetMetadata(string id)
         {
             AssetBase asset = null;

OpenSim/Region/CoreModules/ServiceConnectorsOut/Asset/LocalAssetServiceConnector.cs

@@ -165,6 +165,14 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Asset
             return asset;
         }
 
+        public AssetBase GetCached(string id)
+        {
+            if (m_Cache != null)
+                return m_Cache.Get(id);
+
+            return null;
+        }
+
         public AssetMetadata GetMetadata(string id)
         {
             AssetBase asset = null;

OpenSim/Services/AssetService/AssetService.cs

@@ -93,6 +93,11 @@ namespace OpenSim.Services.AssetService
             return m_Database.GetAsset(assetID);
         }
 
+        public AssetBase GetCached(string id)
+        {
+            return Get(id);
+        }
+
         public AssetMetadata GetMetadata(string id)
         {
             UUID assetID;

OpenSim/Services/Connectors/Asset/AssetServiceConnector.cs

@@ -111,6 +111,14 @@ namespace OpenSim.Services.Connectors
             return asset;
         }
 
+        public AssetBase GetCached(string id)
+        {
+            if (m_Cache != null)
+                return m_Cache.Get(id);
+
+            return null;
+        }
+
         public AssetMetadata GetMetadata(string id)
         {
             if (m_Cache != null)

OpenSim/Services/Connectors/Asset/HGAssetServiceConnector.cs

@@ -116,6 +116,20 @@ namespace OpenSim.Services.Connectors
             return null;
         }
 
+        public AssetBase GetCached(string id)
+        {
+            string url = string.Empty;
+            string assetID = string.Empty;
+
+            if (StringToUrlAndAssetID(id, out url, out assetID))
+            {
+                IAssetService connector = GetConnector(url);
+                return connector.GetCached(assetID);
+            }
+
+            return null;
+        }
+
         public AssetMetadata GetMetadata(string id)
         {
             string url = string.Empty;

OpenSim/Services/Connectors/SimianGrid/SimianAssetServiceConnector.cs

@@ -123,6 +123,14 @@ namespace OpenSim.Services.Connectors.SimianGrid
             return GetRemote(id);
         }
 
+        public AssetBase GetCached(string id)
+        {
+            if (m_cache != null)
+                return m_cache.Get(id);
+
+            return null;
+        }
+
         /// <summary>
         /// Get an asset's metadata
         /// </summary>

OpenSim/Services/Interfaces/IAssetService.cs

@@ -50,6 +50,13 @@ namespace OpenSim.Services.Interfaces
         
         byte[] GetData(string id);
 
+        /// <summary>
+        /// Synchronously fetches an asset from the local cache only
+        /// </summary>
+        /// <param name="id">Asset ID</param>
+        /// <returns>The fetched asset, or null if it did not exist in the local cache</returns>
+        AssetBase GetCached(string id);
+
         /// <summary>
         /// Get an asset synchronously or asynchronously (depending on whether 
         /// it is locally cached) and fire a callback with the fetched asset

OpenSim/Tests/Common/Mock/MockAssetService.cs

@@ -65,6 +65,11 @@ namespace OpenSim.Tests.Common.Mock
             return asset;
         }
 
+        public AssetBase GetCached(string id)
+        {
+            return Get(id);
+        }
+
         public AssetMetadata GetMetadata(string id)
         {
             throw new System.NotImplementedException();