* This is Melanie's XEngine script engine. I've not tested this real well, however, it's confirmed to compile and OpenSimulator to run successfully without this script engine active.

1 files changed, 1438 insertions, 0 deletions

diff --git a/ThirdParty/SmartThreadPool/SmartThreadPool.cs b/ThirdParty/SmartThreadPool/SmartThreadPool.cs
new file mode 100644
index 0000000..c21984e
--- /dev/null
+++ b/ThirdParty/SmartThreadPool/SmartThreadPool.cs
@@ -0,0 +1,1438 @@
+// Ami Bar
+// amibar@gmail.com
+//
+// Smart thread pool in C#.
+// 7 Aug 2004 - Initial release
+// 14 Sep 2004 - Bug fixes 
+// 15 Oct 2004 - Added new features
+//        - Work items return result.
+//        - Support waiting synchronization for multiple work items.
+//        - Work items can be cancelled.
+//        - Passage of the caller thread’s context to the thread in the pool.
+//        - Minimal usage of WIN32 handles.
+//        - Minor bug fixes.
+// 26 Dec 2004 - Changes:
+//        - Removed static constructors.
+//      - Added finalizers.
+//        - Changed Exceptions so they are serializable.
+//        - Fixed the bug in one of the SmartThreadPool constructors.
+//        - Changed the SmartThreadPool.WaitAll() so it will support any number of waiters. 
+//        The SmartThreadPool.WaitAny() is still limited by the .NET Framework.
+//        - Added PostExecute with options on which cases to call it.
+//      - Added option to dispose of the state objects.
+//      - Added a WaitForIdle() method that waits until the work items queue is empty.
+//      - Added an STPStartInfo class for the initialization of the thread pool.
+//      - Changed exception handling so if a work item throws an exception it 
+//        is rethrown at GetResult(), rather then firing an UnhandledException event.
+//        Note that PostExecute exception are always ignored.
+// 25 Mar 2005 - Changes:
+//        - Fixed lost of work items bug
+// 3 Jul 2005: Changes.
+//      - Fixed bug where Enqueue() throws an exception because PopWaiter() returned null, hardly reconstructed. 
+// 16 Aug 2005: Changes.
+//        - Fixed bug where the InUseThreads becomes negative when canceling work items. 
+//
+// 31 Jan 2006 - Changes:
+//        - Added work items priority
+//        - Removed support of chained delegates in callbacks and post executes (nobody really use this)
+//        - Added work items groups
+//        - Added work items groups idle event
+//        - Changed SmartThreadPool.WaitAll() behavior so when it gets empty array
+//          it returns true rather then throwing an exception.
+//        - Added option to start the STP and the WIG as suspended
+//        - Exception behavior changed, the real exception is returned by an 
+//          inner exception
+//        - Added option to keep the Http context of the caller thread. (Thanks to Steven T.)
+//        - Added performance counters
+//        - Added priority to the threads in the pool
+//
+// 13 Feb 2006 - Changes:
+//        - Added a call to the dispose of the Performance Counter so
+//          their won't be a Performance Counter leak.
+//        - Added exception catch in case the Performance Counters cannot 
+//          be created.
+
+using System;
+using System.Security;
+using System.Threading;
+using System.Collections;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+using Amib.Threading.Internal;
+
+namespace Amib.Threading
+{
+    #region SmartThreadPool class
+    /// <summary>
+    /// Smart thread pool class.
+    /// </summary>
+    public class SmartThreadPool : IWorkItemsGroup, IDisposable
+    {
+        #region Default Constants
+
+        /// <summary>
+        /// Default minimum number of threads the thread pool contains. (0)
+        /// </summary>
+        public const int DefaultMinWorkerThreads = 0;
+
+        /// <summary>
+        /// Default maximum number of threads the thread pool contains. (25)
+        /// </summary>
+        public const int DefaultMaxWorkerThreads = 25;
+
+        /// <summary>
+        /// Default idle timeout in milliseconds. (One minute)
+        /// </summary>
+        public const int DefaultIdleTimeout = 60*1000; // One minute
+
+        /// <summary>
+        /// Indicate to copy the security context of the caller and then use it in the call. (false)
+        /// </summary>
+        public const bool DefaultUseCallerCallContext = false; 
+
+        /// <summary>
+        /// Indicate to copy the HTTP context of the caller and then use it in the call. (false)
+        /// </summary>
+        public const bool DefaultUseCallerHttpContext = false;
+
+        /// <summary>
+        /// Indicate to dispose of the state objects if they support the IDispose interface. (false)
+        /// </summary>
+        public const bool DefaultDisposeOfStateObjects = false; 
+
+        /// <summary>
+        /// The default option to run the post execute
+        /// </summary>
+        public const CallToPostExecute DefaultCallToPostExecute = CallToPostExecute.Always;
+
+        /// <summary>
+        /// The default post execute method to run. 
+        /// When null it means not to call it.
+        /// </summary>
+        public static readonly PostExecuteWorkItemCallback DefaultPostExecuteWorkItemCallback = null;
+
+        /// <summary>
+        /// The default work item priority
+        /// </summary>
+        public const WorkItemPriority DefaultWorkItemPriority = WorkItemPriority.Normal;
+
+        /// <summary>
+        /// The default is to work on work items as soon as they arrive
+        /// and not to wait for the start.
+        /// </summary>
+        public const bool DefaultStartSuspended = false;
+
+        /// <summary>
+        /// The default is not to use the performance counters
+        /// </summary>
+        public static readonly string DefaultPerformanceCounterInstanceName = null;
+
+        public static readonly int DefaultStackSize = 0;
+
+        /// <summary>
+        /// The default thread priority
+        /// </summary>
+        public const ThreadPriority DefaultThreadPriority = ThreadPriority.Normal;
+
+        #endregion
+
+        #region Member Variables
+
+        /// <summary>
+        /// Contains the name of this instance of SmartThreadPool.
+        /// Can be changed by the user.
+        /// </summary>
+        private string _name = "SmartThreadPool";
+
+        /// <summary>
+        /// Hashtable of all the threads in the thread pool.
+        /// </summary>
+        private Hashtable _workerThreads = Hashtable.Synchronized(new Hashtable());
+
+        /// <summary>
+        /// Queue of work items.
+        /// </summary>
+        private WorkItemsQueue _workItemsQueue = new WorkItemsQueue();
+
+        /// <summary>
+        /// Count the work items handled.
+        /// Used by the performance counter.
+        /// </summary>
+        private long _workItemsProcessed = 0;
+
+        /// <summary>
+        /// Number of threads that currently work (not idle).
+        /// </summary>
+        private int _inUseWorkerThreads = 0;
+
+        /// <summary>
+        /// Start information to use. 
+        /// It is simpler than providing many constructors.
+        /// </summary>
+        private STPStartInfo _stpStartInfo = new STPStartInfo();
+
+        /// <summary>
+        /// Total number of work items that are stored in the work items queue 
+        /// plus the work items that the threads in the pool are working on.
+        /// </summary>
+        private int _currentWorkItemsCount = 0;
+
+        /// <summary>
+        /// Signaled when the thread pool is idle, i.e. no thread is busy
+        /// and the work items queue is empty
+        /// </summary>
+        private ManualResetEvent _isIdleWaitHandle = new ManualResetEvent(true);
+
+        /// <summary>
+        /// An event to signal all the threads to quit immediately.
+        /// </summary>
+        private ManualResetEvent _shuttingDownEvent = new ManualResetEvent(false);
+
+        /// <summary>
+        /// A flag to indicate the threads to quit.
+        /// </summary>
+        private bool _shutdown = false;
+
+        /// <summary>
+        /// Counts the threads created in the pool.
+        /// It is used to name the threads.
+        /// </summary>
+        private int _threadCounter = 0;
+
+        /// <summary>
+        /// Indicate that the SmartThreadPool has been disposed
+        /// </summary>
+        private bool _isDisposed = false;
+
+        /// <summary>
+        /// Event to send that the thread pool is idle
+        /// </summary>
+        private event EventHandler _stpIdle;
+
+        /// <summary>
+        /// On idle event
+        /// </summary>
+        //private event WorkItemsGroupIdleHandler _onIdle;
+
+        /// <summary>
+        /// Holds all the WorkItemsGroup instaces that have at least one 
+        /// work item int the SmartThreadPool
+        /// This variable is used in case of Shutdown
+        /// </summary>
+        private Hashtable _workItemsGroups = Hashtable.Synchronized(new Hashtable());
+
+        /// <summary>
+        /// A reference from each thread in the thread pool to its SmartThreadPool
+        /// object container.
+        /// With this variable a thread can know whatever it belongs to a 
+        /// SmartThreadPool.
+        /// </summary>
+        [ThreadStatic]
+        private static SmartThreadPool _smartThreadPool;
+
+        /// <summary>
+        /// A reference to the current work item a thread from the thread pool 
+        /// is executing.
+        /// </summary>
+        [ThreadStatic]
+        private static WorkItem _currentWorkItem;
+
+        /// <summary>
+        /// STP performance counters
+        /// </summary>
+        private ISTPInstancePerformanceCounters _pcs = NullSTPInstancePerformanceCounters.Instance;
+
+        #endregion
+
+        #region Construction and Finalization
+
+        /// <summary>
+        /// Constructor
+        /// </summary>
+        public SmartThreadPool()
+        {
+            Initialize();
+        }
+
+        /// <summary>
+        /// Constructor
+        /// </summary>
+        /// <param name="idleTimeout">Idle timeout in milliseconds</param>
+        public SmartThreadPool(int idleTimeout)
+        {
+            _stpStartInfo.IdleTimeout = idleTimeout;
+            Initialize();
+        }
+
+        /// <summary>
+        /// Constructor
+        /// </summary>
+        /// <param name="idleTimeout">Idle timeout in milliseconds</param>
+        /// <param name="maxWorkerThreads">Upper limit of threads in the pool</param>
+        public SmartThreadPool(
+            int idleTimeout,
+            int maxWorkerThreads)
+        {
+            _stpStartInfo.IdleTimeout = idleTimeout;
+            _stpStartInfo.MaxWorkerThreads = maxWorkerThreads;
+            Initialize();
+        }
+
+        /// <summary>
+        /// Constructor
+        /// </summary>
+        /// <param name="idleTimeout">Idle timeout in milliseconds</param>
+        /// <param name="maxWorkerThreads">Upper limit of threads in the pool</param>
+        /// <param name="minWorkerThreads">Lower limit of threads in the pool</param>
+        public SmartThreadPool(
+            int idleTimeout,
+            int maxWorkerThreads,
+            int minWorkerThreads)
+        {
+            _stpStartInfo.IdleTimeout = idleTimeout;
+            _stpStartInfo.MaxWorkerThreads = maxWorkerThreads;
+            _stpStartInfo.MinWorkerThreads = minWorkerThreads;
+            Initialize();
+        }
+
+        /// <summary>
+        /// Constructor
+        /// </summary>
+        public SmartThreadPool(STPStartInfo stpStartInfo)
+        {
+            _stpStartInfo = new STPStartInfo(stpStartInfo);
+            Initialize();
+        }
+
+        private void Initialize()
+        {
+            ValidateSTPStartInfo();
+
+            if (null != _stpStartInfo.PerformanceCounterInstanceName)
+            {
+                try
+                {
+                    _pcs = new STPInstancePerformanceCounters(_stpStartInfo.PerformanceCounterInstanceName);
+                }
+                catch(Exception e)
+                {
+                    Debug.WriteLine("Unable to create Performance Counters: " + e.ToString());
+                    _pcs = NullSTPInstancePerformanceCounters.Instance;
+                }
+            }
+
+            StartOptimalNumberOfThreads();
+        }
+
+        private void StartOptimalNumberOfThreads()
+        {
+            int threadsCount = Math.Max(_workItemsQueue.Count, _stpStartInfo.MinWorkerThreads);
+            threadsCount = Math.Min(threadsCount, _stpStartInfo.MaxWorkerThreads);
+            StartThreads(threadsCount);
+        }
+
+        private void ValidateSTPStartInfo()
+        {
+            if (_stpStartInfo.MinWorkerThreads < 0)
+            {
+                throw new ArgumentOutOfRangeException(
+                    "MinWorkerThreads", "MinWorkerThreads cannot be negative");
+            }
+
+            if (_stpStartInfo.MaxWorkerThreads <= 0)
+            {
+                throw new ArgumentOutOfRangeException(
+                    "MaxWorkerThreads", "MaxWorkerThreads must be greater than zero");
+            }
+
+            if (_stpStartInfo.MinWorkerThreads > _stpStartInfo.MaxWorkerThreads)
+            {
+                throw new ArgumentOutOfRangeException(
+                    "MinWorkerThreads, maxWorkerThreads", 
+                    "MaxWorkerThreads must be greater or equal to MinWorkerThreads");
+            }
+        }
+
+        private void ValidateCallback(Delegate callback)
+        {
+            if(callback.GetInvocationList().Length > 1)
+            {
+                throw new NotSupportedException("SmartThreadPool doesn't support delegates chains");
+            }
+        }
+
+        #endregion
+
+        #region Thread Processing
+
+        /// <summary>
+        /// Waits on the queue for a work item, shutdown, or timeout.
+        /// </summary>
+        /// <returns>
+        /// Returns the WaitingCallback or null in case of timeout or shutdown.
+        /// </returns>
+        private WorkItem Dequeue()
+        {
+            WorkItem workItem = 
+                _workItemsQueue.DequeueWorkItem(_stpStartInfo.IdleTimeout, _shuttingDownEvent);
+
+            return workItem;
+        }
+
+        /// <summary>
+        /// Put a new work item in the queue
+        /// </summary>
+        /// <param name="workItem">A work item to queue</param>
+        private void Enqueue(WorkItem workItem)
+        {
+            Enqueue(workItem, true);
+        }
+
+        /// <summary>
+        /// Put a new work item in the queue
+        /// </summary>
+        /// <param name="workItem">A work item to queue</param>
+        internal void Enqueue(WorkItem workItem, bool incrementWorkItems)
+        {
+            // Make sure the workItem is not null
+            Debug.Assert(null != workItem);
+
+            if (incrementWorkItems)
+            {
+                IncrementWorkItemsCount();
+            }
+
+            _workItemsQueue.EnqueueWorkItem(workItem);
+            workItem.WorkItemIsQueued();
+
+            // If all the threads are busy then try to create a new one
+            if ((InUseThreads + WaitingCallbacks) > _workerThreads.Count) 
+            {
+                StartThreads(1);
+            }
+        }
+
+        private void IncrementWorkItemsCount()
+        {
+            _pcs.SampleWorkItems(_workItemsQueue.Count, _workItemsProcessed);
+
+            int count = Interlocked.Increment(ref _currentWorkItemsCount);
+            //Trace.WriteLine("WorkItemsCount = " + _currentWorkItemsCount.ToString());
+            if (count == 1) 
+            {
+                //Trace.WriteLine("STP is NOT idle");
+                _isIdleWaitHandle.Reset();
+            }
+        }
+
+        private void DecrementWorkItemsCount()
+        {
+            ++_workItemsProcessed;
+
+            // The counter counts even if the work item was cancelled
+            _pcs.SampleWorkItems(_workItemsQueue.Count, _workItemsProcessed);
+
+            int count = Interlocked.Decrement(ref _currentWorkItemsCount);
+            //Trace.WriteLine("WorkItemsCount = " + _currentWorkItemsCount.ToString());
+            if (count == 0) 
+            {
+                //Trace.WriteLine("STP is idle");
+                _isIdleWaitHandle.Set();
+            }
+        }
+
+        internal void RegisterWorkItemsGroup(IWorkItemsGroup workItemsGroup)
+        {
+            _workItemsGroups[workItemsGroup] = workItemsGroup;
+        }
+
+        internal void UnregisterWorkItemsGroup(IWorkItemsGroup workItemsGroup)
+        {
+            if (_workItemsGroups.Contains(workItemsGroup))
+            {
+                _workItemsGroups.Remove(workItemsGroup);
+            }
+        }
+
+        /// <summary>
+        /// Inform that the current thread is about to quit or quiting.
+        /// The same thread may call this method more than once.
+        /// </summary>
+        private void InformCompleted()
+        {
+            // There is no need to lock the two methods together 
+            // since only the current thread removes itself
+            // and the _workerThreads is a synchronized hashtable
+            if (_workerThreads.Contains(Thread.CurrentThread))
+            {
+                _workerThreads.Remove(Thread.CurrentThread);
+                _pcs.SampleThreads(_workerThreads.Count, _inUseWorkerThreads);
+            }
+        }
+
+        /// <summary>
+        /// Starts new threads
+        /// </summary>
+        /// <param name="threadsCount">The number of threads to start</param>
+        private void StartThreads(int threadsCount)
+        {
+            if (_stpStartInfo.StartSuspended)
+            {
+                return;
+            }
+
+            lock(_workerThreads.SyncRoot)
+            {
+                // Don't start threads on shut down
+                if (_shutdown)
+                {
+                    return;
+                }
+
+                for(int i = 0; i < threadsCount; ++i)
+                {
+                    // Don't create more threads then the upper limit
+                    if (_workerThreads.Count >= _stpStartInfo.MaxWorkerThreads)
+                    {
+                        return;
+                    }
+
+                    // Create a new thread
+                    Thread workerThread = new Thread(new ThreadStart(ProcessQueuedItems), _stpStartInfo.StackSize);
+
+                    // Configure the new thread and start it
+                    workerThread.Name = "STP " + Name + " Thread #" + _threadCounter;
+                    workerThread.IsBackground = true;
+                    workerThread.Priority = _stpStartInfo.ThreadPriority;
+                    workerThread.Start();
+                    ++_threadCounter;
+
+                    // Add the new thread to the hashtable and update its creation
+                    // time.
+                    _workerThreads[workerThread] = DateTime.Now;
+                    _pcs.SampleThreads(_workerThreads.Count, _inUseWorkerThreads);
+                }
+            }
+        }
+
+        /// <summary>
+        /// A worker thread method that processes work items from the work items queue.
+        /// </summary>
+        private void ProcessQueuedItems()
+        {
+            // Initialize the _smartThreadPool variable
+            _smartThreadPool = this;
+
+            try
+            {
+                bool bInUseWorkerThreadsWasIncremented = false;
+
+                // Process until shutdown.
+                while(!_shutdown)
+                {
+                    // Update the last time this thread was seen alive.
+                    // It's good for debugging.
+                    _workerThreads[Thread.CurrentThread] = DateTime.Now;
+
+                    // Wait for a work item, shutdown, or timeout
+                    WorkItem workItem = Dequeue();
+
+                    // Update the last time this thread was seen alive.
+                    // It's good for debugging.
+                    _workerThreads[Thread.CurrentThread] = DateTime.Now;
+
+                    // On timeout or shut down.
+                    if (null == workItem)
+                    {
+                        // Double lock for quit.
+                        if (_workerThreads.Count > _stpStartInfo.MinWorkerThreads)
+                        {
+                            lock(_workerThreads.SyncRoot)
+                            {
+                                if (_workerThreads.Count > _stpStartInfo.MinWorkerThreads)
+                                {
+                                    // Inform that the thread is quiting and then quit.
+                                    // This method must be called within this lock or else
+                                    // more threads will quit and the thread pool will go
+                                    // below the lower limit.
+                                    InformCompleted();
+                                    break;
+                                }
+                            }
+                        }
+                    }
+
+                    // If we didn't quit then skip to the next iteration.
+                    if (null == workItem)
+                    {
+                        continue;
+                    }
+
+                    try 
+                    {
+                        // Initialize the value to false
+                        bInUseWorkerThreadsWasIncremented = false;
+
+                        // Change the state of the work item to 'in progress' if possible.
+                        // We do it here so if the work item has been canceled we won't 
+                        // increment the _inUseWorkerThreads.
+                        // The cancel mechanism doesn't delete items from the queue,  
+                        // it marks the work item as canceled, and when the work item
+                        // is dequeued, we just skip it.
+                        // If the post execute of work item is set to always or to
+                        // call when the work item is canceled then the StartingWorkItem()
+                        // will return true, so the post execute can run.
+                        if (!workItem.StartingWorkItem())
+                        {
+                            continue;
+                        }
+
+                        // Execute the callback.  Make sure to accurately
+                        // record how many callbacks are currently executing.
+                        int inUseWorkerThreads = Interlocked.Increment(ref _inUseWorkerThreads);
+                        _pcs.SampleThreads(_workerThreads.Count, inUseWorkerThreads);
+
+                        // Mark that the _inUseWorkerThreads incremented, so in the finally{}
+                        // statement we will decrement it correctly.
+                        bInUseWorkerThreadsWasIncremented = true;
+
+                        // Set the _currentWorkItem to the current work item
+                        _currentWorkItem = workItem;
+
+                        lock(workItem)
+                        {
+                            workItem.currentThread = Thread.CurrentThread;
+                        }
+
+                        ExecuteWorkItem(workItem);
+
+                        lock(workItem)
+                        {
+                            workItem.currentThread = null;
+                        }
+
+                    }
+                    catch(ThreadAbortException ex)
+                    {
+                        lock(workItem)
+                        {
+                            workItem.currentThread = null;
+                        }
+                        ex.GetHashCode();
+                        Thread.ResetAbort();
+                    }
+                    catch(Exception ex)
+                    {
+                        ex.GetHashCode();
+                        // Do nothing
+                    }
+                    finally
+                    {
+                        lock(workItem)
+                        {
+                            workItem.currentThread = null;
+                        }
+
+                        if (null != workItem)
+                        {
+                            workItem.DisposeOfState();
+                        }
+
+                        // Set the _currentWorkItem to null, since we 
+                        // no longer run user's code.
+                        _currentWorkItem = null;
+
+                        // Decrement the _inUseWorkerThreads only if we had 
+                        // incremented it. Note the cancelled work items don't
+                        // increment _inUseWorkerThreads.
+                        if (bInUseWorkerThreadsWasIncremented)
+                        {
+                            int inUseWorkerThreads = Interlocked.Decrement(ref _inUseWorkerThreads);
+                            _pcs.SampleThreads(_workerThreads.Count, inUseWorkerThreads);
+                        }
+
+                        // Notify that the work item has been completed.
+                        // WorkItemsGroup may enqueue their next work item.
+                        workItem.FireWorkItemCompleted();
+
+                        // Decrement the number of work items here so the idle 
+                        // ManualResetEvent won't fluctuate.
+                        DecrementWorkItemsCount();
+                    }
+                }
+            } 
+            catch(ThreadAbortException tae)
+            {
+                tae.GetHashCode();
+                // Handle the abort exception gracfully.
+                Thread.ResetAbort();
+            }
+            catch(Exception e)
+            {
+                Debug.Assert(null != e);
+            }
+            finally
+            {
+                InformCompleted();
+            }
+        }
+
+        private void ExecuteWorkItem(WorkItem workItem)
+        {
+            _pcs.SampleWorkItemsWaitTime(workItem.WaitingTime);
+            try
+            {
+                workItem.Execute();
+            }
+            catch
+            {
+                throw;
+            }
+            finally
+            {
+                _pcs.SampleWorkItemsProcessTime(workItem.ProcessTime);
+            }
+        }
+
+
+        #endregion
+
+        #region Public Methods
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="callback">A callback to execute</param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(WorkItemCallback callback)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, callback);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="callback">A callback to execute</param>
+        /// <param name="workItemPriority">The priority of the work item</param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(WorkItemCallback callback, WorkItemPriority workItemPriority)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, callback, workItemPriority);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="workItemInfo">Work item info</param>
+        /// <param name="callback">A callback to execute</param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(WorkItemInfo workItemInfo, WorkItemCallback callback)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, workItemInfo, callback);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="callback">A callback to execute</param>
+        /// <param name="state">
+        /// The context object of the work item. Used for passing arguments to the work item. 
+        /// </param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(WorkItemCallback callback, object state)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, callback, state);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="callback">A callback to execute</param>
+        /// <param name="state">
+        /// The context object of the work item. Used for passing arguments to the work item. 
+        /// </param>
+        /// <param name="workItemPriority">The work item priority</param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(WorkItemCallback callback, object state, WorkItemPriority workItemPriority)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, callback, state, workItemPriority);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="workItemInfo">Work item information</param>
+        /// <param name="callback">A callback to execute</param>
+        /// <param name="state">
+        /// The context object of the work item. Used for passing arguments to the work item. 
+        /// </param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(WorkItemInfo workItemInfo, WorkItemCallback callback, object state)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, workItemInfo, callback, state);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="callback">A callback to execute</param>
+        /// <param name="state">
+        /// The context object of the work item. Used for passing arguments to the work item. 
+        /// </param>
+        /// <param name="postExecuteWorkItemCallback">
+        /// A delegate to call after the callback completion
+        /// </param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(
+            WorkItemCallback callback, 
+            object state,
+            PostExecuteWorkItemCallback postExecuteWorkItemCallback)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, callback, state, postExecuteWorkItemCallback);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="callback">A callback to execute</param>
+        /// <param name="state">
+        /// The context object of the work item. Used for passing arguments to the work item. 
+        /// </param>
+        /// <param name="postExecuteWorkItemCallback">
+        /// A delegate to call after the callback completion
+        /// </param>
+        /// <param name="workItemPriority">The work item priority</param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(
+            WorkItemCallback callback, 
+            object state,
+            PostExecuteWorkItemCallback postExecuteWorkItemCallback,
+            WorkItemPriority workItemPriority)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, callback, state, postExecuteWorkItemCallback, workItemPriority);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="callback">A callback to execute</param>
+        /// <param name="state">
+        /// The context object of the work item. Used for passing arguments to the work item. 
+        /// </param>
+        /// <param name="postExecuteWorkItemCallback">
+        /// A delegate to call after the callback completion
+        /// </param>
+        /// <param name="callToPostExecute">Indicates on which cases to call to the post execute callback</param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(
+            WorkItemCallback callback, 
+            object state,
+            PostExecuteWorkItemCallback postExecuteWorkItemCallback,
+            CallToPostExecute callToPostExecute)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, callback, state, postExecuteWorkItemCallback, callToPostExecute);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Queue a work item
+        /// </summary>
+        /// <param name="callback">A callback to execute</param>
+        /// <param name="state">
+        /// The context object of the work item. Used for passing arguments to the work item. 
+        /// </param>
+        /// <param name="postExecuteWorkItemCallback">
+        /// A delegate to call after the callback completion
+        /// </param>
+        /// <param name="callToPostExecute">Indicates on which cases to call to the post execute callback</param>
+        /// <param name="workItemPriority">The work item priority</param>
+        /// <returns>Returns a work item result</returns>
+        public IWorkItemResult QueueWorkItem(
+            WorkItemCallback callback, 
+            object state,
+            PostExecuteWorkItemCallback postExecuteWorkItemCallback,
+            CallToPostExecute callToPostExecute,
+            WorkItemPriority workItemPriority)
+        {
+            ValidateNotDisposed();
+            ValidateCallback(callback);
+            WorkItem workItem = WorkItemFactory.CreateWorkItem(this, _stpStartInfo, callback, state, postExecuteWorkItemCallback, callToPostExecute, workItemPriority);
+            Enqueue(workItem);
+            return workItem.GetWorkItemResult();
+        }
+
+        /// <summary>
+        /// Wait for the thread pool to be idle
+        /// </summary>
+        public void WaitForIdle()
+        {
+            WaitForIdle(Timeout.Infinite);
+        }
+
+        /// <summary>
+        /// Wait for the thread pool to be idle
+        /// </summary>
+        public bool WaitForIdle(TimeSpan timeout)
+        {
+            return WaitForIdle((int)timeout.TotalMilliseconds);
+        }
+
+        /// <summary>
+        /// Wait for the thread pool to be idle
+        /// </summary>
+        public bool WaitForIdle(int millisecondsTimeout)
+        {
+            ValidateWaitForIdle();
+            return _isIdleWaitHandle.WaitOne(millisecondsTimeout, false);
+        }
+
+        private void ValidateWaitForIdle()
+        {
+            if(_smartThreadPool == this)
+            {
+                throw new NotSupportedException(
+                    "WaitForIdle cannot be called from a thread on its SmartThreadPool, it will cause may cause a deadlock");
+            }
+        }
+
+        internal void ValidateWorkItemsGroupWaitForIdle(IWorkItemsGroup workItemsGroup)
+        {
+            ValidateWorkItemsGroupWaitForIdleImpl(workItemsGroup, SmartThreadPool._currentWorkItem);
+            if ((null != workItemsGroup) && 
+                (null != SmartThreadPool._currentWorkItem) &&
+                SmartThreadPool._currentWorkItem.WasQueuedBy(workItemsGroup))
+            {
+                throw new NotSupportedException("WaitForIdle cannot be called from a thread on its SmartThreadPool, it will cause may cause a deadlock");
+            }
+        }
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private void ValidateWorkItemsGroupWaitForIdleImpl(IWorkItemsGroup workItemsGroup, WorkItem workItem)
+        {
+            if ((null != workItemsGroup) && 
+                (null != workItem) &&
+                workItem.WasQueuedBy(workItemsGroup))
+            {
+                throw new NotSupportedException("WaitForIdle cannot be called from a thread on its SmartThreadPool, it will cause may cause a deadlock");
+            }
+        }
+
+
+
+        /// <summary>
+        /// Force the SmartThreadPool to shutdown
+        /// </summary>
+        public void Shutdown()
+        {
+            Shutdown(true, 0);
+        }
+
+        public void Shutdown(bool forceAbort, TimeSpan timeout)
+        {
+            Shutdown(forceAbort, (int)timeout.TotalMilliseconds);
+        }
+
+        /// <summary>
+        /// Empties the queue of work items and abort the threads in the pool.
+        /// </summary>
+        public void Shutdown(bool forceAbort, int millisecondsTimeout)
+        {
+            ValidateNotDisposed();
+
+            ISTPInstancePerformanceCounters pcs = _pcs;
+
+            if (NullSTPInstancePerformanceCounters.Instance != _pcs)
+            {
+                _pcs.Dispose();
+                // Set the _pcs to "null" to stop updating the performance
+                // counters
+                _pcs = NullSTPInstancePerformanceCounters.Instance;
+            }
+
+            Thread [] threads = null;
+            lock(_workerThreads.SyncRoot)
+            {
+                // Shutdown the work items queue
+                _workItemsQueue.Dispose();
+
+                // Signal the threads to exit
+                _shutdown = true;
+                _shuttingDownEvent.Set();
+
+                // Make a copy of the threads' references in the pool
+                threads = new Thread [_workerThreads.Count];
+                _workerThreads.Keys.CopyTo(threads, 0);
+            }
+
+            int millisecondsLeft = millisecondsTimeout;
+            DateTime start = DateTime.Now;
+            bool waitInfinitely = (Timeout.Infinite == millisecondsTimeout);
+            bool timeout = false;
+
+            // Each iteration we update the time left for the timeout.
+            foreach(Thread thread in threads)
+            {
+                // Join don't work with negative numbers
+                if (!waitInfinitely && (millisecondsLeft < 0))
+                {
+                    timeout = true;
+                    break;
+                }
+
+                // Wait for the thread to terminate
+                bool success = thread.Join(millisecondsLeft);
+                if(!success)
+                {
+                    timeout = true;
+                    break;
+                }
+
+                if(!waitInfinitely)
+                {
+                    // Update the time left to wait
+                    TimeSpan ts = DateTime.Now - start;
+                    millisecondsLeft = millisecondsTimeout - (int)ts.TotalMilliseconds;
+                }
+            }
+
+            if (timeout && forceAbort)
+            {
+                // Abort the threads in the pool
+                foreach(Thread thread in threads)
+                {
+                    if ((thread != null) && thread.IsAlive) 
+                    {
+                        try 
+                        {
+                            thread.Abort("Shutdown");
+                        }
+                        catch(SecurityException e)
+                        {
+                            e.GetHashCode();
+                        }
+                        catch(ThreadStateException ex)
+                        {
+                            ex.GetHashCode();
+                            // In case the thread has been terminated 
+                            // after the check if it is alive.
+                        }
+                    }
+                }
+            }
+
+            // Dispose of the performance counters
+            pcs.Dispose();
+        }
+
+        /// <summary>
+        /// Wait for all work items to complete
+        /// </summary>
+        /// <param name="workItemResults">Array of work item result objects</param>
+        /// <returns>
+        /// true when every work item in workItemResults has completed; otherwise false.
+        /// </returns>
+        public static bool WaitAll(
+            IWorkItemResult [] workItemResults)
+        {
+            return WaitAll(workItemResults, Timeout.Infinite, true);
+        }
+
+        /// <summary>
+        /// Wait for all work items to complete
+        /// </summary>
+        /// <param name="workItemResults">Array of work item result objects</param>
+        /// <param name="timeout">The number of milliseconds to wait, or a TimeSpan that represents -1 milliseconds 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>
+        /// <returns>
+        /// true when every work item in workItemResults has completed; otherwise false.
+        /// </returns>
+        public static bool WaitAll(
+            IWorkItemResult [] workItemResults,
+            TimeSpan timeout,
+            bool exitContext)
+        {
+            return WaitAll(workItemResults, (int)timeout.TotalMilliseconds, exitContext);
+        }
+
+        /// <summary>
+        /// Wait for all work items to complete
+        /// </summary>
+        /// <param name="workItemResults">Array of work item result objects</param>
+        /// <param name="timeout">The number of milliseconds to wait, or a TimeSpan that represents -1 milliseconds 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.
+        /// </returns>
+        public static bool WaitAll(
+            IWorkItemResult [] workItemResults,  
+            TimeSpan timeout,
+            bool exitContext,
+            WaitHandle cancelWaitHandle)
+        {
+            return WaitAll(workItemResults, (int)timeout.TotalMilliseconds, exitContext, cancelWaitHandle);
+        }
+
+        /// <summary>
+        /// Wait for all work items to complete
+        /// </summary>
+        /// <param name="workItemResults">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>
+        /// <returns>
+        /// true when every work item in workItemResults has completed; otherwise false.
+        /// </returns>
+        public static bool WaitAll(
+            IWorkItemResult [] workItemResults,  
+            int millisecondsTimeout,
+            bool exitContext)
+        {
+            return WorkItem.WaitAll(workItemResults, millisecondsTimeout, exitContext, null);
+        }
+
+        /// <summary>
+        /// Wait for all work items to complete
+        /// </summary>
+        /// <param name="workItemResults">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.
+        /// </returns>
+        public static bool WaitAll(
+            IWorkItemResult [] workItemResults,  
+            int millisecondsTimeout,
+            bool exitContext,
+            WaitHandle cancelWaitHandle)
+        {
+            return WorkItem.WaitAll(workItemResults, millisecondsTimeout, exitContext, cancelWaitHandle);
+        }
+
+
+        /// <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>
+        /// <returns>
+        /// The array index of the work item result that satisfied the wait, or WaitTimeout if any of the work items has been canceled.
+        /// </returns>
+        public static int WaitAny(
+            IWorkItemResult [] workItemResults)
+        {
+            return WaitAny(workItemResults, Timeout.Infinite, true);
+        }
+
+        /// <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="timeout">The number of milliseconds to wait, or a TimeSpan that represents -1 milliseconds 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>
+        /// <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>
+        public static int WaitAny(
+            IWorkItemResult [] workItemResults,
+            TimeSpan timeout,
+            bool exitContext)
+        {
+            return WaitAny(workItemResults, (int)timeout.TotalMilliseconds, exitContext);
+        }
+
+        /// <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="timeout">The number of milliseconds to wait, or a TimeSpan that represents -1 milliseconds 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>
+        /// 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>
+        public static int WaitAny(
+            IWorkItemResult [] workItemResults,
+            TimeSpan timeout,
+            bool exitContext,
+            WaitHandle cancelWaitHandle)
+        {
+            return WaitAny(workItemResults, (int)timeout.TotalMilliseconds, exitContext, cancelWaitHandle);
+        }
+
+        /// <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="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>
+        /// <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>
+        public static int WaitAny(
+            IWorkItemResult [] workItemResults,  
+            int millisecondsTimeout,
+            bool exitContext)
+        {
+            return WorkItem.WaitAny(workItemResults, millisecondsTimeout, exitContext, null);
+        }
+
+        /// <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="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>
+        /// 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>
+        public static int WaitAny(
+            IWorkItemResult [] workItemResults,  
+            int millisecondsTimeout,
+            bool exitContext,
+            WaitHandle cancelWaitHandle)
+        {
+            return WorkItem.WaitAny(workItemResults, millisecondsTimeout, exitContext, cancelWaitHandle);
+        }
+
+        public IWorkItemsGroup CreateWorkItemsGroup(int concurrency)
+        {
+            IWorkItemsGroup workItemsGroup = new WorkItemsGroup(this, concurrency, _stpStartInfo);
+            return workItemsGroup;
+        }
+
+        public IWorkItemsGroup CreateWorkItemsGroup(int concurrency, WIGStartInfo wigStartInfo)
+        {
+            IWorkItemsGroup workItemsGroup = new WorkItemsGroup(this, concurrency, wigStartInfo);
+            return workItemsGroup;
+        }
+
+        public event WorkItemsGroupIdleHandler OnIdle
+        {
+            add
+            {
+                throw new NotImplementedException("This event is not implemented in the SmartThreadPool class. Please create a WorkItemsGroup in order to use this feature.");
+                //_onIdle += value;
+            }
+            remove
+            {
+                throw new NotImplementedException("This event is not implemented in the SmartThreadPool class. Please create a WorkItemsGroup in order to use this feature.");
+                //_onIdle -= value;
+            }
+        }
+
+        public void Cancel()
+        {
+            ICollection workItemsGroups = _workItemsGroups.Values;
+            foreach(WorkItemsGroup workItemsGroup in workItemsGroups)
+            {
+                workItemsGroup.Cancel();
+            }
+        }
+
+        public void Start()
+        {
+            lock (this)
+            {
+                if (!this._stpStartInfo.StartSuspended)
+                {
+                    return;
+                }
+                _stpStartInfo.StartSuspended = false;
+            }
+            
+            ICollection workItemsGroups = _workItemsGroups.Values;
+            foreach(WorkItemsGroup workItemsGroup in workItemsGroups)
+            {
+                workItemsGroup.OnSTPIsStarting();
+            }
+
+            StartOptimalNumberOfThreads();
+        }
+
+        #endregion
+
+        #region Properties
+
+        /// <summary>
+        /// Get/Set the name of the SmartThreadPool instance
+        /// </summary>
+        public string Name 
+        { 
+            get
+            {
+                return _name;
+            }
+
+            set
+            {
+                _name = value;
+            }
+        }
+
+        /// <summary>
+        /// Get the lower limit of threads in the pool.
+        /// </summary>
+        public int MinThreads 
+        { 
+            get 
+            {
+                ValidateNotDisposed();
+                return _stpStartInfo.MinWorkerThreads; 
+            }
+        }
+
+        /// <summary>
+        /// Get the upper limit of threads in the pool.
+        /// </summary>
+        public int MaxThreads 
+        { 
+            get 
+            {
+                ValidateNotDisposed();
+                return _stpStartInfo.MaxWorkerThreads; 
+            } 
+        }
+        /// <summary>
+        /// Get the number of threads in the thread pool.
+        /// Should be between the lower and the upper limits.
+        /// </summary>
+        public int ActiveThreads 
+        { 
+            get 
+            {
+                ValidateNotDisposed();
+                return _workerThreads.Count; 
+            } 
+        }
+
+        /// <summary>
+        /// Get the number of busy (not idle) threads in the thread pool.
+        /// </summary>
+        public int InUseThreads 
+        { 
+            get 
+            { 
+                ValidateNotDisposed();
+                return _inUseWorkerThreads; 
+            } 
+        }
+
+        /// <summary>
+        /// Get the number of work items in the queue.
+        /// </summary>
+        public int WaitingCallbacks 
+        { 
+            get 
+            { 
+                ValidateNotDisposed();
+                return _workItemsQueue.Count;
+            } 
+        }
+
+
+        public event EventHandler Idle
+        {
+            add
+            {
+                _stpIdle += value;
+            }
+
+            remove
+            {
+                _stpIdle -= value;
+            }
+        }
+
+        #endregion
+
+        #region IDisposable Members
+
+//        ~SmartThreadPool()
+//        {
+//            Dispose();
+//        }
+
+        public void Dispose()
+        {
+            if (!_isDisposed)
+            {
+                if (!_shutdown)
+                {
+                    Shutdown();
+                }
+
+                if (null != _shuttingDownEvent)
+                {
+                    _shuttingDownEvent.Close();
+                    _shuttingDownEvent = null;
+                }
+                _workerThreads.Clear();
+                _isDisposed = true;
+                GC.SuppressFinalize(this);
+            }
+        }
+
+        private void ValidateNotDisposed()
+        {
+            if(_isDisposed)
+            {
+                throw new ObjectDisposedException(GetType().ToString(), "The SmartThreadPool has been shutdown");
+            }
+        }
+        #endregion
+    }
+    #endregion
+}