1 files changed, 51 insertions, 15 deletions

diff --git a/OpenSim/Region/CoreModules/ServiceConnectorsOut/Inventory/InventoryCache.cs b/OpenSim/Region/CoreModules/ServiceConnectorsOut/Inventory/InventoryCache.cs
index 1e434b9..2fc8ee3 100644
--- a/OpenSim/Region/CoreModules/ServiceConnectorsOut/Inventory/InventoryCache.cs
+++ b/OpenSim/Region/CoreModules/ServiceConnectorsOut/Inventory/InventoryCache.cs
@@ -1,11 +1,41 @@
-using System;
-using System.Collections.Generic;
+/*
+ * 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.Generic;
+using System.Threading;
 using OpenSim.Framework;
 using OpenMetaverse;
 
 namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Inventory
 {
+    /// <summary>
+    /// Cache root and system inventory folders to reduce number of potentially remote inventory calls and associated holdups.
+    /// </summary>
     public class InventoryCache
     {
         private const double CACHE_EXPIRATION_SECONDS = 3600.0; // 1 hour
@@ -16,8 +46,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Inventory
 
         public void Cache(UUID userID, InventoryFolderBase root)
         {
-            lock (m_RootFolders)
-                m_RootFolders.AddOrUpdate(userID, root, CACHE_EXPIRATION_SECONDS);
+            m_RootFolders.AddOrUpdate(userID, root, CACHE_EXPIRATION_SECONDS);
         }
 
         public InventoryFolderBase GetRootFolder(UUID userID)
@@ -31,14 +60,18 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Inventory
 
         public void Cache(UUID userID, AssetType type, InventoryFolderBase folder)
         {
-            lock (m_FolderTypes)
+            Dictionary<AssetType, InventoryFolderBase> ff = null;
+            if (!m_FolderTypes.TryGetValue(userID, out ff))
+            {
+                ff = new Dictionary<AssetType, InventoryFolderBase>();
+                m_FolderTypes.Add(userID, ff, CACHE_EXPIRATION_SECONDS);
+            }
+
+            // We need to lock here since two threads could potentially retrieve the same dictionary
+            // and try to add a folder for that type simultaneously.  Dictionary<>.Add() is not described as thread-safe in the SDK
+            // even if the folders are identical.
+            lock (ff)
             {
-                Dictionary<AssetType, InventoryFolderBase> ff = null;
-                if (!m_FolderTypes.TryGetValue(userID, out ff))
-                {
-                    ff = new Dictionary<AssetType, InventoryFolderBase>();
-                    m_FolderTypes.Add(userID, ff, CACHE_EXPIRATION_SECONDS);
-                }
                 if (!ff.ContainsKey(type))
                     ff.Add(type, folder);
             }
@@ -50,8 +83,12 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Inventory
             if (m_FolderTypes.TryGetValue(userID, out ff))
             {
                 InventoryFolderBase f = null;
-                if (ff.TryGetValue(type, out f))
-                    return f;
+
+                lock (ff)
+                {
+                    if (ff.TryGetValue(type, out f))
+                        return f;
+                }
             }
 
             return null;
@@ -59,8 +96,7 @@ namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.Inventory
 
         public void Cache(UUID userID, InventoryCollection inv)
         {
-            lock (m_Inventories)
-                m_Inventories.AddOrUpdate(userID, inv, 120);
+            m_Inventories.AddOrUpdate(userID, inv, 120);
         }
 
         public InventoryCollection GetUserInventory(UUID userID)