1 files changed, 313 insertions, 346 deletions

diff --git a/ThirdParty/SmartThreadPool/WorkItem.cs b/ThirdParty/SmartThreadPool/WorkItem.cs
index d0c0524..185f10c 100644
--- a/ThirdParty/SmartThreadPool/WorkItem.cs
+++ b/ThirdParty/SmartThreadPool/WorkItem.cs
@@ -1,58 +1,13 @@
-// Ami Bar
-// amibar@gmail.com
-
 using System;
 using System.Threading;
 using System.Diagnostics;
 
 namespace Amib.Threading.Internal
 {
-    #region WorkItem Delegate
-
-    /// <summary>
-    /// An internal delegate to call when the WorkItem starts or completes
-    /// </summary>
-    internal delegate void WorkItemStateCallback(WorkItem workItem);
-
-    #endregion
-
-    #region IInternalWorkItemResult interface 
-
-    public class CanceledWorkItemsGroup
-    {
-        public readonly static CanceledWorkItemsGroup NotCanceledWorkItemsGroup = new CanceledWorkItemsGroup();
-
-        private bool _isCanceled = false;
-        public bool IsCanceled 
-        { 
-            get { return _isCanceled; }
-            set { _isCanceled = value; }
-        }
-    }
-
-    internal interface IInternalWorkItemResult
-    {
-        event WorkItemStateCallback OnWorkItemStarted;
-        event WorkItemStateCallback OnWorkItemCompleted;
-    }
-
-    #endregion
-
-    #region IWorkItem interface
-
-    public interface IWorkItem
-    {
-
-    }
-
-    #endregion
-
-    #region WorkItem class
-
     /// <summary>
     /// Holds a callback delegate and the state for that delegate.
     /// </summary>
-    public class WorkItem : IHasWorkItemPriority, IWorkItem
+    public partial class WorkItem : IHasWorkItemPriority
     {
         #region WorkItemState enum
 
@@ -61,33 +16,57 @@ namespace Amib.Threading.Internal
         /// </summary>
         private enum WorkItemState
         {
-            InQueue,
-            InProgress,
-            Completed,
-            Canceled,
+            InQueue = 0,    // Nexts: InProgress, Canceled
+            InProgress = 1,    // Nexts: Completed, Canceled
+            Completed = 2,    // Stays Completed
+            Canceled = 3,    // Stays Canceled
         }
 
-        #endregion
+        private static bool IsValidStatesTransition(WorkItemState currentState, WorkItemState nextState)
+        {
+            bool valid = false;
+
+            switch (currentState)
+            {
+                case WorkItemState.InQueue:
+                    valid = (WorkItemState.InProgress == nextState) || (WorkItemState.Canceled == nextState);
+                    break;
+                case WorkItemState.InProgress:
+                    valid = (WorkItemState.Completed == nextState) || (WorkItemState.Canceled == nextState);
+                    break;
+                case WorkItemState.Completed:
+                case WorkItemState.Canceled:
+                    // Cannot be changed
+                    break;
+                default:
+                    // Unknown state
+                    Debug.Assert(false);
+                    break;
+            }
 
-        #region Member Variables
+            return valid;
+        }
 
-        public Thread currentThread;
+        #endregion
+
+        #region Fields
 
         /// <summary>
         /// Callback delegate for the callback.
         /// </summary>
-        private WorkItemCallback _callback;
+        private readonly WorkItemCallback _callback;
 
         /// <summary>
         /// State with which to call the callback delegate.
         /// </summary>
         private object _state;
 
+#if !(_WINDOWS_CE) && !(_SILVERLIGHT) && !(WINDOWS_PHONE)
         /// <summary>
         /// Stores the caller's context
         /// </summary>
-        private CallerThreadContext _callerContext;
-
+        private readonly CallerThreadContext _callerContext;
+#endif
         /// <summary>
         /// Holds the result of the mehtod
         /// </summary>
@@ -117,12 +96,12 @@ namespace Amib.Threading.Internal
         /// <summary>
         /// Represents the result state of the work item
         /// </summary>
-        private WorkItemResult _workItemResult;
+        private readonly WorkItemResult _workItemResult;
 
         /// <summary>
         /// Work item info
         /// </summary>
-        private WorkItemInfo _workItemInfo;
+        private readonly WorkItemInfo _workItemInfo;
 
         /// <summary>
         /// Called when the WorkItem starts
@@ -141,30 +120,41 @@ namespace Amib.Threading.Internal
         private CanceledWorkItemsGroup _canceledWorkItemsGroup = CanceledWorkItemsGroup.NotCanceledWorkItemsGroup;
 
         /// <summary>
+        /// A reference to an object that indicates whatever the 
+        /// SmartThreadPool has been canceled
+        /// </summary>
+        private CanceledWorkItemsGroup _canceledSmartThreadPool = CanceledWorkItemsGroup.NotCanceledWorkItemsGroup;
+
+        /// <summary>
         /// The work item group this work item belong to.
-        /// 
         /// </summary>
-        private IWorkItemsGroup _workItemsGroup;
+        private readonly IWorkItemsGroup _workItemsGroup;
 
-        #region Performance Counter fields
+        /// <summary>
+        /// The thread that executes this workitem.
+        /// This field is available for the period when the work item is executed, before and after it is null.
+        /// </summary>
+        private Thread _executingThread;
 
         /// <summary>
-        /// The time when the work items is queued.
-        /// Used with the performance counter.
+        /// The absulote time when the work item will be timeout
         /// </summary>
-        private DateTime _queuedTime;
+        private long _expirationTime;
+
+        #region Performance Counter fields
+
+
+
 
         /// <summary>
-        /// The time when the work items starts its execution.
-        /// Used with the performance counter.
+        /// Stores how long the work item waited on the stp queue
         /// </summary>
-        private DateTime _beginProcessTime;
+        private Stopwatch _waitingOnQueueStopwatch;
 
         /// <summary>
-        /// The time when the work items ends its execution.
-        /// Used with the performance counter.
+        /// Stores how much time it took the work item to execute after it went out of the queue
         /// </summary>
-        private DateTime _endProcessTime;
+        private Stopwatch _processingStopwatch;
 
         #endregion
 
@@ -174,17 +164,25 @@ namespace Amib.Threading.Internal
 
         public TimeSpan WaitingTime
         {
-            get 
+            get
             {
-                return (_beginProcessTime - _queuedTime);
+                return _waitingOnQueueStopwatch.Elapsed;
             }
         }
 
         public TimeSpan ProcessTime
         {
-            get 
+            get
+            {
+                return _processingStopwatch.Elapsed;
+            }
+        }
+
+        internal WorkItemInfo WorkItemInfo
+        {
+            get
             {
-                return (_endProcessTime - _beginProcessTime);
+                return _workItemInfo;
             }
         }
 
@@ -195,6 +193,8 @@ namespace Amib.Threading.Internal
         /// <summary>
         /// Initialize the callback holding object.
         /// </summary>
+        /// <param name="workItemsGroup">The workItemGroup of the workitem</param>
+        /// <param name="workItemInfo">The WorkItemInfo of te workitem</param>
         /// <param name="callback">Callback delegate for the callback.</param>
         /// <param name="state">State with which to call the callback delegate.</param>
         /// 
@@ -203,16 +203,18 @@ namespace Amib.Threading.Internal
         public WorkItem(
             IWorkItemsGroup workItemsGroup,
             WorkItemInfo workItemInfo,
-            WorkItemCallback callback, 
+            WorkItemCallback callback,
             object state)
         {
             _workItemsGroup = workItemsGroup;
             _workItemInfo = workItemInfo;
 
+#if !(_WINDOWS_CE) && !(_SILVERLIGHT) && !(WINDOWS_PHONE)
             if (_workItemInfo.UseCallerCallContext || _workItemInfo.UseCallerHttpContext)
             {
                 _callerContext = CallerThreadContext.Capture(_workItemInfo.UseCallerCallContext, _workItemInfo.UseCallerHttpContext);
             }
+#endif
 
             _callback = callback;
             _state = state;
@@ -222,9 +224,18 @@ namespace Amib.Threading.Internal
 
         internal void Initialize()
         {
+            // The _workItemState is changed directly instead of using the SetWorkItemState
+            // method since we don't want to go throught IsValidStateTransition.
             _workItemState = WorkItemState.InQueue;
+
             _workItemCompleted = null;
             _workItemCompletedRefCount = 0;
+            _waitingOnQueueStopwatch = new Stopwatch();
+            _processingStopwatch = new Stopwatch();
+            _expirationTime =
+                _workItemInfo.Timeout > 0 ?
+                DateTime.UtcNow.Ticks + _workItemInfo.Timeout * TimeSpan.TicksPerMillisecond :
+                long.MaxValue;
         }
 
         internal bool WasQueuedBy(IWorkItemsGroup workItemsGroup)
@@ -237,17 +248,16 @@ namespace Amib.Threading.Internal
 
         #region Methods
 
-        public CanceledWorkItemsGroup CanceledWorkItemsGroup
+        internal CanceledWorkItemsGroup CanceledWorkItemsGroup
         {
-            get
-            {
-                return _canceledWorkItemsGroup;
-            }
+            get { return _canceledWorkItemsGroup; }
+            set { _canceledWorkItemsGroup = value; }
+        }
 
-            set
-            {
-                _canceledWorkItemsGroup = value;
-            }
+        internal CanceledWorkItemsGroup CanceledSmartThreadPool
+        {
+            get { return _canceledSmartThreadPool; }
+            set { _canceledSmartThreadPool = value; }
         }
 
         /// <summary>
@@ -259,9 +269,10 @@ namespace Amib.Threading.Internal
         /// </returns>
         public bool StartingWorkItem()
         {
-            _beginProcessTime = DateTime.Now;
+            _waitingOnQueueStopwatch.Stop();
+            _processingStopwatch.Start();
 
-            lock(this)
+            lock (this)
             {
                 if (IsCanceled)
                 {
@@ -277,6 +288,9 @@ namespace Amib.Threading.Internal
 
                 Debug.Assert(WorkItemState.InQueue == GetWorkItemState());
 
+                // No need for a lock yet, only after the state has changed to InProgress
+                _executingThread = Thread.CurrentThread;
+
                 SetWorkItemState(WorkItemState.InProgress);
             }
 
@@ -291,7 +305,7 @@ namespace Amib.Threading.Internal
             CallToPostExecute currentCallToPostExecute = 0;
 
             // Execute the work item if we are in the correct state
-            switch(GetWorkItemState())
+            switch (GetWorkItemState())
             {
                 case WorkItemState.InProgress:
                     currentCallToPostExecute |= CallToPostExecute.WhenWorkItemNotCanceled;
@@ -311,7 +325,7 @@ namespace Amib.Threading.Internal
                 PostExecute();
             }
 
-            _endProcessTime = DateTime.Now;
+            _processingStopwatch.Stop();
         }
 
         internal void FireWorkItemCompleted()
@@ -323,8 +337,21 @@ namespace Amib.Threading.Internal
                     _workItemCompletedEvent(this);
                 }
             }
-            catch // Ignore exceptions
-            {}
+            catch // Suppress exceptions
+            { }
+        }
+
+        internal void FireWorkItemStarted()
+        {
+            try
+            {
+                if (null != _workItemStartedEvent)
+                {
+                    _workItemStartedEvent(this);
+                }
+            }
+            catch // Suppress exceptions
+            { }
         }
 
         /// <summary>
@@ -332,32 +359,70 @@ namespace Amib.Threading.Internal
         /// </summary>
         private void ExecuteWorkItem()
         {
+
+#if !(_WINDOWS_CE) && !(_SILVERLIGHT) && !(WINDOWS_PHONE)
             CallerThreadContext ctc = null;
             if (null != _callerContext)
             {
                 ctc = CallerThreadContext.Capture(_callerContext.CapturedCallContext, _callerContext.CapturedHttpContext);
                 CallerThreadContext.Apply(_callerContext);
             }
+#endif
 
             Exception exception = null;
             object result = null;
 
             try
             {
-                result = _callback(_state);
+                try
+                {
+                    result = _callback(_state);
+                }
+                catch (Exception e)
+                {
+                    // Save the exception so we can rethrow it later
+                    exception = e;
+                }
+
+                // Remove the value of the execution thread, so it will be impossible to cancel the work item,
+                // since it is already completed.
+                // Cancelling a work item that already completed may cause the abortion of the next work item!!!
+                Thread executionThread = Interlocked.CompareExchange(ref _executingThread, null, _executingThread);
+
+                if (null == executionThread)
+                {
+                    // Oops! we are going to be aborted..., Wait here so we can catch the ThreadAbortException
+                    Thread.Sleep(60 * 1000);
+
+                    // If after 1 minute this thread was not aborted then let it continue working.
+                }
             }
-            catch (Exception e) 
+            // We must treat the ThreadAbortException or else it will be stored in the exception variable
+            catch (ThreadAbortException tae)
             {
-                // Save the exception so we can rethrow it later
-                exception = e;
+                tae.GetHashCode();
+                // Check if the work item was cancelled
+                // If we got a ThreadAbortException and the STP is not shutting down, it means the 
+                // work items was cancelled.
+                if (!SmartThreadPool.CurrentThreadEntry.AssociatedSmartThreadPool.IsShuttingdown)
+                {
+#if !(_WINDOWS_CE) && !(_SILVERLIGHT) && !(WINDOWS_PHONE)
+                    Thread.ResetAbort();
+#endif
+                }
             }
-        
+
+#if !(_WINDOWS_CE) && !(_SILVERLIGHT) && !(WINDOWS_PHONE)
             if (null != _callerContext)
             {
                 CallerThreadContext.Apply(ctc);
             }
+#endif
 
-            SetResult(result, exception);
+            if (!SmartThreadPool.IsWorkItemCanceled)
+            {
+                SetResult(result, exception);
+            }
         }
 
         /// <summary>
@@ -369,9 +434,9 @@ namespace Amib.Threading.Internal
             {
                 try
                 {
-                    _workItemInfo.PostExecuteWorkItemCallback(this._workItemResult);
+                    _workItemInfo.PostExecuteWorkItemCallback(_workItemResult);
                 }
-                catch (Exception e) 
+                catch (Exception e)
                 {
                     Debug.Assert(null != e);
                 }
@@ -382,6 +447,8 @@ namespace Amib.Threading.Internal
         /// Set the result of the work item to return
         /// </summary>
         /// <param name="result">The result of the work item</param>
+        /// <param name="exception">The exception that was throw while the workitem executed, null
+        /// if there was no exception.</param>
         internal void SetResult(object result, Exception exception)
         {
             _result = result;
@@ -401,48 +468,48 @@ namespace Amib.Threading.Internal
         /// <summary>
         /// Wait for all work items to complete
         /// </summary>
-        /// <param name="workItemResults">Array of work item result objects</param>
+        /// <param name="waitableResults">Array of work item result objects</param>
         /// <param name="millisecondsTimeout">The number of milliseconds to wait, or Timeout.Infinite (-1) to wait indefinitely.</param>
         /// <param name="exitContext">
         /// true to exit the synchronization domain for the context before the wait (if in a synchronized context), and reacquire it; otherwise, false. 
         /// </param>
         /// <param name="cancelWaitHandle">A cancel wait handle to interrupt the wait if needed</param>
         /// <returns>
-        /// true when every work item in workItemResults has completed; otherwise false.
+        /// true when every work item in waitableResults has completed; otherwise false.
         /// </returns>
         internal static bool WaitAll(
-            IWorkItemResult [] workItemResults,
+            IWaitableResult[] waitableResults,
             int millisecondsTimeout,
             bool exitContext,
             WaitHandle cancelWaitHandle)
         {
-            if (0 == workItemResults.Length)
+            if (0 == waitableResults.Length)
             {
                 return true;
             }
 
             bool success;
-            WaitHandle [] waitHandles = new WaitHandle[workItemResults.Length];;
-            GetWaitHandles(workItemResults, waitHandles);
+            WaitHandle[] waitHandles = new WaitHandle[waitableResults.Length];
+            GetWaitHandles(waitableResults, waitHandles);
 
             if ((null == cancelWaitHandle) && (waitHandles.Length <= 64))
             {
-                success = WaitHandle.WaitAll(waitHandles, millisecondsTimeout, exitContext);
+                success = STPEventWaitHandle.WaitAll(waitHandles, millisecondsTimeout, exitContext);
             }
             else
             {
                 success = true;
                 int millisecondsLeft = millisecondsTimeout;
-                DateTime start = DateTime.Now;
+                Stopwatch stopwatch = Stopwatch.StartNew();
 
-                WaitHandle [] whs;
+                WaitHandle[] whs;
                 if (null != cancelWaitHandle)
                 {
-                    whs = new WaitHandle [] { null, cancelWaitHandle };
+                    whs = new WaitHandle[] { null, cancelWaitHandle };
                 }
                 else
                 {
-                    whs = new WaitHandle [] { null };
+                    whs = new WaitHandle[] { null };
                 }
 
                 bool waitInfinitely = (Timeout.Infinite == millisecondsTimeout);
@@ -450,7 +517,7 @@ namespace Amib.Threading.Internal
                 // We cannot use WaitHandle.WaitAll directly, because the cancelWaitHandle
                 // won't affect it.
                 // Each iteration we update the time left for the timeout.
-                for(int i = 0; i < workItemResults.Length; ++i)
+                for (int i = 0; i < waitableResults.Length; ++i)
                 {
                     // WaitAny don't work with negative numbers
                     if (!waitInfinitely && (millisecondsLeft < 0))
@@ -460,23 +527,22 @@ namespace Amib.Threading.Internal
                     }
 
                     whs[0] = waitHandles[i];
-                    int result = WaitHandle.WaitAny(whs, millisecondsLeft, exitContext);
-                    if((result > 0) || (WaitHandle.WaitTimeout == result))
+                    int result = STPEventWaitHandle.WaitAny(whs, millisecondsLeft, exitContext);
+                    if ((result > 0) || (STPEventWaitHandle.WaitTimeout == result))
                     {
                         success = false;
                         break;
                     }
 
-                    if(!waitInfinitely)
+                    if (!waitInfinitely)
                     {
                         // Update the time left to wait
-                        TimeSpan ts = DateTime.Now - start;
-                        millisecondsLeft = millisecondsTimeout - (int)ts.TotalMilliseconds;
+                        millisecondsLeft = millisecondsTimeout - (int)stopwatch.ElapsedMilliseconds;
                     }
                 }
             }
             // Release the wait handles
-            ReleaseWaitHandles(workItemResults);
+            ReleaseWaitHandles(waitableResults);
 
             return success;
         }
@@ -484,7 +550,7 @@ namespace Amib.Threading.Internal
         /// <summary>
         /// Waits for any of the work items in the specified array to complete, cancel, or timeout
         /// </summary>
-        /// <param name="workItemResults">Array of work item result objects</param>
+        /// <param name="waitableResults">Array of work item result objects</param>
         /// <param name="millisecondsTimeout">The number of milliseconds to wait, or Timeout.Infinite (-1) to wait indefinitely.</param>
         /// <param name="exitContext">
         /// true to exit the synchronization domain for the context before the wait (if in a synchronized context), and reacquire it; otherwise, false. 
@@ -493,38 +559,38 @@ namespace Amib.Threading.Internal
         /// <returns>
         /// The array index of the work item result that satisfied the wait, or WaitTimeout if no work item result satisfied the wait and a time interval equivalent to millisecondsTimeout has passed or the work item has been canceled.
         /// </returns>
-        internal static int WaitAny(            
-            IWorkItemResult [] workItemResults,
+        internal static int WaitAny(
+            IWaitableResult[] waitableResults,
             int millisecondsTimeout,
             bool exitContext,
             WaitHandle cancelWaitHandle)
         {
-            WaitHandle [] waitHandles = null;
+            WaitHandle[] waitHandles;
 
             if (null != cancelWaitHandle)
             {
-                waitHandles = new WaitHandle[workItemResults.Length+1];
-                GetWaitHandles(workItemResults, waitHandles);
-                waitHandles[workItemResults.Length] = cancelWaitHandle;
+                waitHandles = new WaitHandle[waitableResults.Length + 1];
+                GetWaitHandles(waitableResults, waitHandles);
+                waitHandles[waitableResults.Length] = cancelWaitHandle;
             }
             else
             {
-                waitHandles = new WaitHandle[workItemResults.Length];
-                GetWaitHandles(workItemResults, waitHandles);
+                waitHandles = new WaitHandle[waitableResults.Length];
+                GetWaitHandles(waitableResults, waitHandles);
             }
 
-            int result = WaitHandle.WaitAny(waitHandles, millisecondsTimeout, exitContext);
+            int result = STPEventWaitHandle.WaitAny(waitHandles, millisecondsTimeout, exitContext);
 
             // Treat cancel as timeout
             if (null != cancelWaitHandle)
             {
-                if (result == workItemResults.Length)
+                if (result == waitableResults.Length)
                 {
-                    result = WaitHandle.WaitTimeout;
+                    result = STPEventWaitHandle.WaitTimeout;
                 }
             }
 
-            ReleaseWaitHandles(workItemResults);
+            ReleaseWaitHandles(waitableResults);
 
             return result;
         }
@@ -532,16 +598,16 @@ namespace Amib.Threading.Internal
         /// <summary>
         /// Fill an array of wait handles with the work items wait handles.
         /// </summary>
-        /// <param name="workItemResults">An array of work item results</param>
+        /// <param name="waitableResults">An array of work item results</param>
         /// <param name="waitHandles">An array of wait handles to fill</param>
         private static void GetWaitHandles(
-            IWorkItemResult [] workItemResults,
-            WaitHandle [] waitHandles)
+            IWaitableResult[] waitableResults,
+            WaitHandle[] waitHandles)
         {
-            for(int i = 0; i < workItemResults.Length; ++i)
+            for (int i = 0; i < waitableResults.Length; ++i)
             {
-                WorkItemResult wir = workItemResults[i] as WorkItemResult;
-                Debug.Assert(null != wir, "All workItemResults must be WorkItemResult objects");
+                WorkItemResult wir = waitableResults[i].GetWorkItemResult() as WorkItemResult;
+                Debug.Assert(null != wir, "All waitableResults must be WorkItemResult objects");
 
                 waitHandles[i] = wir.GetWorkItem().GetWaitHandle();
             }
@@ -550,40 +616,64 @@ namespace Amib.Threading.Internal
         /// <summary>
         /// Release the work items' wait handles
         /// </summary>
-        /// <param name="workItemResults">An array of work item results</param>
-        private static void ReleaseWaitHandles(IWorkItemResult [] workItemResults)
+        /// <param name="waitableResults">An array of work item results</param>
+        private static void ReleaseWaitHandles(IWaitableResult[] waitableResults)
         {
-            for(int i = 0; i < workItemResults.Length; ++i)
+            for (int i = 0; i < waitableResults.Length; ++i)
             {
-                WorkItemResult wir = workItemResults[i] as WorkItemResult;
+                WorkItemResult wir = (WorkItemResult)waitableResults[i].GetWorkItemResult();
 
                 wir.GetWorkItem().ReleaseWaitHandle();
             }
         }
 
-
         #endregion
-        
+
         #region Private Members
 
         private WorkItemState GetWorkItemState()
         {
-            if (_canceledWorkItemsGroup.IsCanceled)
+            lock (this)
             {
-                return WorkItemState.Canceled;
-            }
-            return _workItemState;
+                if (WorkItemState.Completed == _workItemState)
+                {
+                    return _workItemState;
+                }
+
+                long nowTicks = DateTime.UtcNow.Ticks;
 
+                if (WorkItemState.Canceled != _workItemState && nowTicks > _expirationTime)
+                {
+                    _workItemState = WorkItemState.Canceled;
+                }
+
+                if (WorkItemState.InProgress == _workItemState)
+                {
+                    return _workItemState;
+                }
+
+                if (CanceledSmartThreadPool.IsCanceled || CanceledWorkItemsGroup.IsCanceled)
+                {
+                    return WorkItemState.Canceled;
+                }
+
+                return _workItemState;
+            }
         }
+
+
         /// <summary>
         /// Sets the work item's state
         /// </summary>
         /// <param name="workItemState">The state to set the work item to</param>
         private void SetWorkItemState(WorkItemState workItemState)
         {
-            lock(this)
+            lock (this)
             {
-                _workItemState = workItemState;
+                if (IsValidStatesTransition(_workItemState, workItemState))
+                {
+                    _workItemState = workItemState;
+                }
             }
         }
 
@@ -594,7 +684,7 @@ namespace Amib.Threading.Internal
         private void SignalComplete(bool canceled)
         {
             SetWorkItemState(canceled ? WorkItemState.Canceled : WorkItemState.Completed);
-            lock(this)
+            lock (this)
             {
                 // If someone is waiting then signal.
                 if (null != _workItemCompleted)
@@ -606,40 +696,93 @@ namespace Amib.Threading.Internal
 
         internal void WorkItemIsQueued()
         {
-            _queuedTime = DateTime.Now;
+            _waitingOnQueueStopwatch.Start();
         }
 
         #endregion
-        
+
         #region Members exposed by WorkItemResult
 
         /// <summary>
         /// Cancel the work item if it didn't start running yet.
         /// </summary>
         /// <returns>Returns true on success or false if the work item is in progress or already completed</returns>
-        private bool Cancel()
+        private bool Cancel(bool abortExecution)
         {
-            lock(this)
+#if (_WINDOWS_CE)
+            if(abortExecution)
+            {
+                throw new ArgumentOutOfRangeException("abortExecution", "WindowsCE doesn't support this feature");
+            }
+#endif
+            bool success = false;
+            bool signalComplete = false;
+
+            lock (this)
             {
-                switch(GetWorkItemState())
+                switch (GetWorkItemState())
                 {
                     case WorkItemState.Canceled:
                         //Debug.WriteLine("Work item already canceled");
-                        return true;
+                        if (abortExecution)
+                        {
+                            Thread executionThread = Interlocked.CompareExchange(ref _executingThread, null, _executingThread);
+                            if (null != executionThread)
+                            {
+                                executionThread.Abort(); // "Cancel"
+                                // No need to signalComplete, because we already cancelled this work item
+                                // so it already signaled its completion.
+                                //signalComplete = true;
+                            }
+                        } 
+                        success = true;
+                        break;
                     case WorkItemState.Completed:
-                    case WorkItemState.InProgress:
                         //Debug.WriteLine("Work item cannot be canceled");
-                        return false;
+                        break;
+                    case WorkItemState.InProgress:
+                        if (abortExecution)
+                        {
+                            Thread executionThread = Interlocked.CompareExchange(ref _executingThread, null, _executingThread);
+                            if (null != executionThread)
+                            {
+                                executionThread.Abort(); // "Cancel"
+                                success = true;
+                                signalComplete = true;
+                            }
+                        }
+                        else
+                        {
+                            // **************************
+                            // Stock SmartThreadPool 2.2.3 sets these to true and relies on the thread to check the
+                            // WorkItem cancellation status.  However, OpenSimulator uses a different mechanism to notify
+                            // scripts of co-operative termination and the abort code also relies on this method
+                            // returning false in order to implement a small wait.
+                            //
+                            // Therefore, as was the case previously with STP, we will not signal successful cancellation
+                            // here.  It's possible that OpenSimulator code could be changed in the future to remove
+                            // the need for this change.
+                            // **************************
+                            success = false;
+                            signalComplete = false;
+                        }
+                        break;
                     case WorkItemState.InQueue:
                         // Signal to the wait for completion that the work
                         // item has been completed (canceled). There is no
                         // reason to wait for it to get out of the queue
-                        SignalComplete(true);
+                        signalComplete = true;
                         //Debug.WriteLine("Work item canceled");
-                        return true;
+                        success = true;
+                        break;
+                }
+
+                if (signalComplete)
+                {
+                    SignalComplete(true);
                 }
             }
-            return false;
+            return success;
         }
 
         /// <summary>
@@ -653,7 +796,7 @@ namespace Amib.Threading.Internal
             bool exitContext,
             WaitHandle cancelWaitHandle)
         {
-            Exception e = null;
+            Exception e;
             object result = GetResult(millisecondsTimeout, exitContext, cancelWaitHandle, out e);
             if (null != e)
             {
@@ -694,7 +837,7 @@ namespace Amib.Threading.Internal
             {
                 WaitHandle wh = GetWaitHandle();
 
-                bool timeout = !wh.WaitOne(millisecondsTimeout, exitContext);
+                bool timeout = !STPEventWaitHandle.WaitOne(wh, millisecondsTimeout, exitContext);
 
                 ReleaseWaitHandle();
 
@@ -706,10 +849,10 @@ namespace Amib.Threading.Internal
             else
             {
                 WaitHandle wh = GetWaitHandle();
-                int result = WaitHandle.WaitAny(new WaitHandle[] { wh, cancelWaitHandle });
+                int result = STPEventWaitHandle.WaitAny(new WaitHandle[] { wh, cancelWaitHandle });
                 ReleaseWaitHandle();
 
-                switch(result)
+                switch (result)
                 {
                     case 0:
                         // The work item signaled
@@ -717,7 +860,7 @@ namespace Amib.Threading.Internal
                         // work item (not the get result)
                         break;
                     case 1:
-                    case WaitHandle.WaitTimeout:
+                    case STPEventWaitHandle.WaitTimeout:
                         throw new WorkItemTimeoutException("Work item timeout");
                     default:
                         Debug.Assert(false);
@@ -745,11 +888,11 @@ namespace Amib.Threading.Internal
         /// </summary>
         private WaitHandle GetWaitHandle()
         {
-            lock(this)
+            lock (this)
             {
                 if (null == _workItemCompleted)
                 {
-                    _workItemCompleted = new ManualResetEvent(IsCompleted);
+                    _workItemCompleted = EventWaitHandleFactory.CreateManualResetEvent(IsCompleted);
                 }
                 ++_workItemCompletedRefCount;
             }
@@ -758,7 +901,7 @@ namespace Amib.Threading.Internal
 
         private void ReleaseWaitHandle()
         {
-            lock(this)
+            lock (this)
             {
                 if (null != _workItemCompleted)
                 {
@@ -779,10 +922,10 @@ namespace Amib.Threading.Internal
         {
             get
             {
-                lock(this)
+                lock (this)
                 {
                     WorkItemState workItemState = GetWorkItemState();
-                    return ((workItemState == WorkItemState.Completed) || 
+                    return ((workItemState == WorkItemState.Completed) ||
                             (workItemState == WorkItemState.Canceled));
                 }
             }
@@ -795,7 +938,7 @@ namespace Amib.Threading.Internal
         {
             get
             {
-                lock(this)
+                lock (this)
                 {
                     return (GetWorkItemState() == WorkItemState.Canceled);
                 }
@@ -843,172 +986,6 @@ namespace Amib.Threading.Internal
             }
         }
 
-
-        #region WorkItemResult class
-
-        private class WorkItemResult : IWorkItemResult, IInternalWorkItemResult
-        {
-            /// <summary>
-            /// A back reference to the work item
-            /// </summary>
-            private WorkItem _workItem;
-
-            public WorkItemResult(WorkItem workItem)
-            {
-                _workItem = workItem;
-            }
-
-            internal WorkItem GetWorkItem()
-            {
-                return _workItem;
-            }
-
-            #region IWorkItemResult Members
-
-            public bool IsCompleted
-            {
-                get
-                {
-                    return _workItem.IsCompleted;
-                }
-            }
-
-            public void Abort()
-            {
-                _workItem.Abort();
-            }
-
-            public bool IsCanceled
-            {
-                get
-                {
-                    return _workItem.IsCanceled;
-                }
-            }
-
-            public object GetResult()
-            {
-                return _workItem.GetResult(Timeout.Infinite, true, null);
-            }
-    
-            public object GetResult(int millisecondsTimeout, bool exitContext)
-            {
-                return _workItem.GetResult(millisecondsTimeout, exitContext, null);
-            }
-
-            public object GetResult(TimeSpan timeout, bool exitContext)
-            {
-                return _workItem.GetResult((int)timeout.TotalMilliseconds, exitContext, null);
-            }
-
-            public object GetResult(int millisecondsTimeout, bool exitContext, WaitHandle cancelWaitHandle)
-            {
-                return _workItem.GetResult(millisecondsTimeout, exitContext, cancelWaitHandle);
-            }
-
-            public object GetResult(TimeSpan timeout, bool exitContext, WaitHandle cancelWaitHandle)
-            {
-                return _workItem.GetResult((int)timeout.TotalMilliseconds, exitContext, cancelWaitHandle);
-            }
-
-            public object GetResult(out Exception e)
-            {
-                return _workItem.GetResult(Timeout.Infinite, true, null, out e);
-            }
-    
-            public object GetResult(int millisecondsTimeout, bool exitContext, out Exception e)
-            {
-                return _workItem.GetResult(millisecondsTimeout, exitContext, null, out e);
-            }
-
-            public object GetResult(TimeSpan timeout, bool exitContext, out Exception e)
-            {
-                return _workItem.GetResult((int)timeout.TotalMilliseconds, exitContext, null, out e);
-            }
-
-            public object GetResult(int millisecondsTimeout, bool exitContext, WaitHandle cancelWaitHandle, out Exception e)
-            {
-                return _workItem.GetResult(millisecondsTimeout, exitContext, cancelWaitHandle, out e);
-            }
-
-            public object GetResult(TimeSpan timeout, bool exitContext, WaitHandle cancelWaitHandle, out Exception e)
-            {
-                return _workItem.GetResult((int)timeout.TotalMilliseconds, exitContext, cancelWaitHandle, out e);
-            }
-
-            public bool Cancel()
-            {
-                return _workItem.Cancel();
-            }
-
-            public object State
-            {
-                get
-                {
-                    return _workItem._state;
-                }
-            }
-
-            public WorkItemPriority WorkItemPriority 
-            { 
-                get
-                {
-                    return _workItem._workItemInfo.WorkItemPriority;
-                }
-            }
-
-            /// <summary>
-            /// Return the result, same as GetResult()
-            /// </summary>
-            public object Result
-            {
-                get { return GetResult(); }
-            }
-
-            /// <summary>
-            /// Returns the exception if occured otherwise returns null.
-            /// This value is valid only after the work item completed,
-            /// before that it is always null.
-            /// </summary>
-            public object Exception
-            {
-                get { return _workItem._exception; }
-            }
-
-            #endregion
-
-            #region IInternalWorkItemResult Members
-
-            public event WorkItemStateCallback OnWorkItemStarted
-            {
-                add
-                {
-                    _workItem.OnWorkItemStarted += value;
-                }
-                remove
-                {
-                    _workItem.OnWorkItemStarted -= value;
-                }
-            }
-
-
-            public event WorkItemStateCallback OnWorkItemCompleted
-            {
-                add
-                {
-                    _workItem.OnWorkItemCompleted += value;
-                }
-                remove
-                {
-                    _workItem.OnWorkItemCompleted -= value;
-                }
-            }
-
-            #endregion
-        }
-
-        #endregion
-
         public void DisposeOfState()
         {
             if (_workItemInfo.DisposeOfStateObjects)
@@ -1021,15 +998,5 @@ namespace Amib.Threading.Internal
                 }
             }
         }
-
-        public void Abort()
-        {
-            lock (this)
-            {
-                if(currentThread != null)
-                    currentThread.Abort();
-            }
-        }
     }
-    #endregion
 }