1 files changed, 183 insertions, 6 deletions

diff --git a/OpenSim/Framework/TaskInventoryDictionary.cs b/OpenSim/Framework/TaskInventoryDictionary.cs
index 8af2c41..62ecbd1 100644
--- a/OpenSim/Framework/TaskInventoryDictionary.cs
+++ b/OpenSim/Framework/TaskInventoryDictionary.cs
@@ -27,9 +27,13 @@
 
 using System;
 using System.Collections.Generic;
+using System.Threading;
+using System.Reflection;
 using System.Xml;
+using System.Diagnostics;
 using System.Xml.Schema;
 using System.Xml.Serialization;
+using log4net;
 using OpenMetaverse;
 
 namespace OpenSim.Framework
@@ -47,6 +51,180 @@ namespace OpenSim.Framework
         // private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
         private static XmlSerializer tiiSerializer = new XmlSerializer(typeof (TaskInventoryItem));
+        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+        
+        private Thread LockedByThread;
+//        private string WriterStack;
+
+//        private Dictionary<Thread, string> ReadLockers =
+//                new Dictionary<Thread, string>();
+
+        /// <value>
+        /// An advanced lock for inventory data
+        /// </value>
+        private System.Threading.ReaderWriterLockSlim m_itemLock = new System.Threading.ReaderWriterLockSlim();
+
+        /// <summary>
+        /// Are we readlocked by the calling thread?
+        /// </summary>
+        public bool IsReadLockedByMe()
+        {
+            if (m_itemLock.RecursiveReadCount > 0)
+            {
+                return true;
+            }
+            else
+            {
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Lock our inventory list for reading (many can read, one can write)
+        /// </summary>
+        public void LockItemsForRead(bool locked)
+        {
+            if (locked)
+            {
+                if (m_itemLock.IsWriteLockHeld && LockedByThread != null)
+                {
+                    if (!LockedByThread.IsAlive)
+                    {
+                        //Locked by dead thread, reset.
+                        m_itemLock = new System.Threading.ReaderWriterLockSlim(); 
+                    }
+                }
+
+                if (m_itemLock.RecursiveReadCount > 0)
+                {
+                    m_log.Error("[TaskInventoryDictionary] Recursive read lock requested. This should not happen and means something needs to be fixed. For now though, it's safe to continue.");
+                    try
+                    {
+                        // That call stack is useful for end users only. RealProgrammers need a full dump. Commented.
+                        // StackTrace stackTrace = new StackTrace();           // get call stack
+                        // StackFrame[] stackFrames = stackTrace.GetFrames();  // get method calls (frames)
+                        //
+                        // // write call stack method names
+                        // foreach (StackFrame stackFrame in stackFrames)
+                        // {
+                        //     m_log.Error("[SceneObjectGroup.m_parts]  "+(stackFrame.GetMethod().Name));   // write method name
+                        // }
+
+                        // The below is far more useful
+//                        System.Console.WriteLine("------------------------------------------");
+//                        System.Console.WriteLine("My call stack:\n" + Environment.StackTrace);
+//                        System.Console.WriteLine("------------------------------------------");
+//                        foreach (KeyValuePair<Thread, string> kvp in ReadLockers)
+//                        {
+//                            System.Console.WriteLine("Locker name {0} call stack:\n" + kvp.Value, kvp.Key.Name);
+//                            System.Console.WriteLine("------------------------------------------");
+//                        }
+                    }
+                    catch
+                    {}
+                    m_itemLock.ExitReadLock();
+                }
+                if (m_itemLock.RecursiveWriteCount > 0)
+                {
+                    m_log.Error("[TaskInventoryDictionary] Recursive write lock requested. This should not happen and means something needs to be fixed.");
+//                    try
+//                    {
+//                        System.Console.WriteLine("------------------------------------------");
+//                        System.Console.WriteLine("My call stack:\n" + Environment.StackTrace);
+//                        System.Console.WriteLine("------------------------------------------");
+//                        System.Console.WriteLine("Locker's call stack:\n" + WriterStack);
+//                        System.Console.WriteLine("------------------------------------------");
+//                    }
+//                    catch
+//                    {}
+                    m_itemLock.ExitWriteLock();
+                }
+                
+                while (!m_itemLock.TryEnterReadLock(60000))
+                {
+                    m_log.Error("Thread lock detected while trying to aquire READ lock in TaskInventoryDictionary. Locked by thread " + LockedByThread.Name + ". I'm going to try to solve the thread lock automatically to preserve region stability, but this needs to be fixed.");
+                    if (m_itemLock.IsWriteLockHeld)
+                    {
+                        m_itemLock = new System.Threading.ReaderWriterLockSlim();
+//                        System.Console.WriteLine("------------------------------------------");
+//                        System.Console.WriteLine("My call stack:\n" + Environment.StackTrace);
+//                        System.Console.WriteLine("------------------------------------------");
+//                        System.Console.WriteLine("Locker's call stack:\n" + WriterStack);
+//                        System.Console.WriteLine("------------------------------------------");
+//                        LockedByThread = null;
+//                        ReadLockers.Clear();
+                    }
+                }
+//                ReadLockers[Thread.CurrentThread] = Environment.StackTrace;
+            }
+            else
+            {
+                if (m_itemLock.RecursiveReadCount>0)
+                {
+                    m_itemLock.ExitReadLock();
+                }
+//                if (m_itemLock.RecursiveReadCount == 0)
+//                    ReadLockers.Remove(Thread.CurrentThread);
+            }
+        }
+
+        /// <summary>
+        /// Lock our inventory list for writing (many can read, one can write)
+        /// </summary>
+        public void LockItemsForWrite(bool locked)
+        {
+            if (locked)
+            {
+                //Enter a write lock, wait indefinately for one to open.
+                if (m_itemLock.RecursiveReadCount > 0)
+                {
+                    m_log.Error("[TaskInventoryDictionary] Recursive read lock requested. This should not happen and means something needs to be fixed. For now though, it's safe to continue.");
+                    m_itemLock.ExitReadLock();
+                }
+                if (m_itemLock.RecursiveWriteCount > 0)
+                {
+                    m_log.Error("[TaskInventoryDictionary] Recursive write lock requested. This should not happen and means something needs to be fixed.");
+
+                    m_itemLock.ExitWriteLock();
+                }
+                while (!m_itemLock.TryEnterWriteLock(60000))
+                {
+                    if (m_itemLock.IsWriteLockHeld)
+                    {
+                        m_log.Error("Thread lock detected while trying to aquire WRITE lock in TaskInventoryDictionary. Locked by thread " + LockedByThread.Name + ". I'm going to try to solve the thread lock automatically to preserve region stability, but this needs to be fixed.");
+//                        System.Console.WriteLine("------------------------------------------");
+//                        System.Console.WriteLine("My call stack:\n" + Environment.StackTrace);
+//                        System.Console.WriteLine("------------------------------------------");
+//                        System.Console.WriteLine("Locker's call stack:\n" + WriterStack);
+//                        System.Console.WriteLine("------------------------------------------");
+                    }
+                    else
+                    {
+                        m_log.Error("Thread lock detected while trying to aquire WRITE lock in TaskInventoryDictionary. Locked by a reader. I'm going to try to solve the thread lock automatically to preserve region stability, but this needs to be fixed.");
+//                        System.Console.WriteLine("------------------------------------------");
+//                        System.Console.WriteLine("My call stack:\n" + Environment.StackTrace);
+//                        System.Console.WriteLine("------------------------------------------");
+//                        foreach (KeyValuePair<Thread, string> kvp in ReadLockers)
+//                        {
+//                            System.Console.WriteLine("Locker name {0} call stack:\n" + kvp.Value, kvp.Key.Name);
+//                            System.Console.WriteLine("------------------------------------------");
+//                        }
+                    }
+                    m_itemLock = new System.Threading.ReaderWriterLockSlim();
+//                    ReadLockers.Clear();
+                }
+
+                LockedByThread = Thread.CurrentThread;
+//                WriterStack = Environment.StackTrace;
+            }
+            else
+            {
+                if (m_itemLock.RecursiveWriteCount > 0)
+                {
+                    m_itemLock.ExitWriteLock();
+                }
+            }
+        }
 
         #region ICloneable Members
 
@@ -54,14 +232,13 @@ namespace OpenSim.Framework
         {
             TaskInventoryDictionary clone = new TaskInventoryDictionary();
 
-            lock (this)
+            m_itemLock.EnterReadLock();
+            foreach (UUID uuid in Keys)
             {
-                foreach (UUID uuid in Keys)
-                {
-                    clone.Add(uuid, (TaskInventoryItem) this[uuid].Clone());
-                }
+                clone.Add(uuid, (TaskInventoryItem) this[uuid].Clone());
             }
-            
+            m_itemLock.ExitReadLock();
+
             return clone;
         }