# HG changeset patch
# User cin
# Date 2018-01-24 00:03:21
# Node ID cbe10ac0731e4edb4d43386f1a3fc3454f6f925c
# Parent  fa6cbf4d8841204bd901308afe0e594dc61387e5

Working on promises

diff --git a/Implab.Fx/StaApartment.cs b/Implab.Fx/StaApartment.cs
--- a/Implab.Fx/StaApartment.cs
+++ b/Implab.Fx/StaApartment.cs
@@ -195,7 +195,7 @@ namespace Implab.Fx {
 
         protected override void Dispose(bool disposing) {
             if (disposing) {
-                if (!m_threadTerminated.IsResolved)
+                if (!m_threadTerminated.IsFulfilled)
                     m_syncContext.Post(x => Application.ExitThread(), null);
             }
             base.Dispose(disposing);
diff --git a/Implab.Test/CancelationTests.cs b/Implab.Test/CancelationTests.cs
--- a/Implab.Test/CancelationTests.cs
+++ b/Implab.Test/CancelationTests.cs
@@ -40,7 +40,7 @@ namespace Implab.Test {
             // cancel the promise
             Assert.IsTrue(p.CancelOperationIfRequested());
             Assert.IsTrue(p.IsCancelled);
-            Assert.AreSame(reason, p.Error);
+            Assert.AreSame(reason, p.RejectReason);
         }
 
         [TestMethod]
@@ -76,7 +76,7 @@ namespace Implab.Test {
             task.Cancel();
             Assert.IsTrue(task.IsCancellationRequested);
             Assert.IsFalse(task.IsCancelled);
-            Assert.IsFalse(task.IsResolved);
+            Assert.IsFalse(task.IsFulfilled);
 
             finish.Set();
             task.Join(1000);
diff --git a/Implab/AbstractEvent.cs b/Implab/AbstractEvent.cs
--- a/Implab/AbstractEvent.cs
+++ b/Implab/AbstractEvent.cs
@@ -2,56 +2,50 @@
 using Implab.Parallels;
 using System.Threading;
 using System.Reflection;
+using System.Diagnostics;
 
 namespace Implab {
-    public abstract class AbstractEvent<THandler> : ICancellable { 
+    public abstract class AbstractEvent<THandler> where THandler : class {
 
-        const int UNRESOLVED_SATE = 0;
-        const int TRANSITIONAL_STATE = 1;
+        const int PENDING_SATE = 0;
+        protected const int TRANSITIONAL_STATE = 1;
+
         protected const int SUCCEEDED_STATE = 2;
         protected const int REJECTED_STATE = 3;
-        protected const int CANCELLED_STATE = 4;
 
-        const int CANCEL_NOT_REQUESTED = 0;
-        const int CANCEL_REQUESTING = 1;
-        const int CANCEL_REQUESTED = 2;
-
-        const int RESERVED_HANDLERS_COUNT = 4;
-
-        int m_state;
+        volatile int m_state;
         Exception m_error;
-        int m_handlersCount;
 
-        //readonly THandler[] m_handlers = new THandler[RESERVED_HANDLERS_COUNT];
-        THandler[] m_handlers;
+        THandler m_handler;
         SimpleAsyncQueue<THandler> m_extraHandlers;
-        int m_handlerPointer = -1;
-        int m_handlersCommited;
-
-        int m_cancelRequest;
-        Exception m_cancelationReason;
 
         #region state managment
-        bool BeginTransit() {
-            return UNRESOLVED_SATE == Interlocked.CompareExchange(ref m_state, TRANSITIONAL_STATE, UNRESOLVED_SATE);
+        protected bool BeginTransit() {
+            return PENDING_SATE == Interlocked.CompareExchange(ref m_state, TRANSITIONAL_STATE, PENDING_SATE);
         }
 
-        void CompleteTransit(int state) {
+        protected void CompleteTransit(int state) {
+#if DEBUG
             if (TRANSITIONAL_STATE != Interlocked.CompareExchange(ref m_state, state, TRANSITIONAL_STATE))
                 throw new InvalidOperationException("Can't complete transition when the object isn't in the transitional state");
+#else
+            m_state = state;
+#endif
+            Signal();
         }
 
-        void WaitTransition() {
-            while (m_state == TRANSITIONAL_STATE) {
-                Thread.MemoryBarrier();
+        protected void WaitTransition() {
+            if (m_state == TRANSITIONAL_STATE) {
+                SpinWait spin;
+                do {
+                    spin.SpinOnce();
+                } while (m_state == TRANSITIONAL_STATE);
             }
         }
 
         protected bool BeginSetResult() {
             if (!BeginTransit()) {
                 WaitTransition();
-                if (m_state != CANCELLED_STATE)
-                    throw new InvalidOperationException("The promise is already resolved");
                 return false;
             }
             return true;
@@ -59,7 +53,6 @@ namespace Implab {
 
         protected void EndSetResult() {
             CompleteTransit(SUCCEEDED_STATE);
-            Signal();
         }
 
 
@@ -78,8 +71,6 @@ namespace Implab {
             if (BeginTransit()) {
                 m_error = error;
                 CompleteTransit(REJECTED_STATE);
-
-                Signal();
             } else {
                 WaitTransition();
                 if (m_state == SUCCEEDED_STATE)
@@ -87,58 +78,33 @@ namespace Implab {
             }
         }
 
-        /// <summary>
-        /// Отменяет операцию, если это возможно.
-        /// </summary>
-        /// <remarks>Для определения была ли операция отменена следует использовать свойство <see cref="IsCancelled"/>.</remarks>
-        protected void SetCancelled(Exception reason) {
-            if (BeginTransit()) {
-                m_error = reason;
-                CompleteTransit(CANCELLED_STATE);
-                Signal();
-            }
-        }
-
         protected abstract void SignalHandler(THandler handler, int signal);
 
         void Signal() {
-            var hp = m_handlerPointer;
-            var slot = hp +1 ;
-            while (slot < m_handlersCommited) {
-                if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) == hp) {
-                    SignalHandler(m_handlers[slot], m_state);
-                }
-                hp = m_handlerPointer;
-                slot = hp +1 ;
-            }
-
-
-            if (m_extraHandlers != null) {
-                THandler handler;
-                while (m_extraHandlers.TryDequeue(out handler))
-                    SignalHandler(handler, m_state);
-            }
+            THandler handler;
+            while (TryDequeueHandler(out handler))
+                SignalHandler(handler, m_state);
         }
 
         #endregion
 
-        protected abstract Signal GetResolveSignal();
+        protected abstract Signal GetFulfillSignal();
 
         #region synchronization traits
         protected void WaitResult(int timeout) {
-            if (!(IsResolved || GetResolveSignal().Wait(timeout)))
+            if (!(IsFulfilled || GetFulfillSignal().Wait(timeout)))
                 throw new TimeoutException();
 
-            switch (m_state) {
-                case SUCCEEDED_STATE:
-                    return;
-                case CANCELLED_STATE:
-                    throw new OperationCanceledException("The operation has been cancelled", m_error);
-                case REJECTED_STATE:
-                    throw new TargetInvocationException(m_error);
-                default:
-                    throw new ApplicationException(String.Format("The promise state {0} is invalid", m_state));
-            }
+            if (IsRejected)
+                Rethrow();
+        }
+
+        protected void Rethrow() {
+            Debug.Assert(m_error != null);
+            if (m_error is OperationCanceledException)
+                throw new OperationCanceledException("Operation cancelled", m_error);
+            else
+                throw new TargetInvocationException(m_error);
         }
         #endregion
 
@@ -150,149 +116,55 @@ namespace Implab {
                 // the promise is in the resolved state, just invoke the handler
                 SignalHandler(handler, m_state);
             } else {
-                var slot = Interlocked.Increment(ref m_handlersCount) - 1;
-
-                if (slot < RESERVED_HANDLERS_COUNT) {
-
-                    if (slot == 0) {
-                        m_handlers = new THandler[RESERVED_HANDLERS_COUNT];
-                    } else {
-                        while (m_handlers == null)
-                            Thread.MemoryBarrier();
-                    }
-
-                    m_handlers[slot] = handler;
-
-                    while (slot != Interlocked.CompareExchange(ref m_handlersCommited, slot + 1, slot)) {
-                    }
+                if (Interlocked.CompareExchange(ref m_handler, handler, null) != null) {
+                    if (m_extraHandlers == null)
+                        // compare-exchange will fprotect from loosing already created queue
+                        Interlocked.CompareExchange(ref m_extraHandlers, new SimpleAsyncQueue<THandler>(), null);
+                    m_extraHandlers.Enqueue(handler);
+                }
 
-                    if (m_state > 1) {
-                        do {
-                            var hp = m_handlerPointer;
-                            slot = hp + 1;
-                            if (slot < m_handlersCommited) {
-                                if (Interlocked.CompareExchange(ref m_handlerPointer, slot, hp) != hp)
-                                    continue;
-                                SignalHandler(m_handlers[slot], m_state);
-                            }
-                            break;
-                        } while(true);
-                    }
-                } else {
-                    if (slot == RESERVED_HANDLERS_COUNT) {
-                        m_extraHandlers = new SimpleAsyncQueue<THandler>();
-                    } else {
-                        while (m_extraHandlers == null)
-                            Thread.MemoryBarrier();
-                    }
-
-                    m_extraHandlers.Enqueue(handler);
-
-                    if (m_state > 1 && m_extraHandlers.TryDequeue(out handler))
+                if (m_state > 1 && TryDequeueHandler(out handler))
                     // if the promise have been resolved while we was adding the handler to the queue
                     // we can't guarantee that someone is still processing it
                     // therefore we need to fetch a handler from the queue and execute it
                     // note that fetched handler may be not the one that we have added
                     // even we can fetch no handlers at all :)
-                        SignalHandler(handler, m_state);
-                }
+                    SignalHandler(handler, m_state);
             }
+
+        }
+
+        bool TryDequeueHandler(out THandler handler) {
+            handler = Interlocked.Exchange(ref m_handler, null);
+            if (handler != null)
+                return true;
+            return m_extraHandlers != null && m_extraHandlers.TryDequeue(out handler);
         }
 
         #endregion
 
         #region IPromise implementation
 
-        public bool IsResolved {
+        public bool IsFulfilled {
             get {
-                Thread.MemoryBarrier();
-                return m_state > 1;
+                return m_state > TRANSITIONAL_STATE;
             }
         }
 
-        public bool IsCancelled {
+        public bool IsRejected {
             get {
-                Thread.MemoryBarrier();
-                return m_state == CANCELLED_STATE;
+                return m_state == REJECTED_STATE;
             }
         }
 
         #endregion
 
-        public Exception Error {
+        public Exception RejectReason {
             get {
                 return m_error;
             }
         }
 
-        public bool CancelOperationIfRequested() {
-            if (IsCancellationRequested) {
-                CancelOperation(CancellationReason);
-                return true;
-            }
-            return false;
-        }
-
-        public virtual void CancelOperation(Exception reason) {
-            SetCancelled(reason);
-        }
-
-        public void CancellationRequested(Action<Exception> handler) {
-            Safe.ArgumentNotNull(handler, "handler");
-            if (IsCancellationRequested)
-                handler(CancellationReason);
-
-            if (m_cancelationHandlers == null)
-                Interlocked.CompareExchange(ref m_cancelationHandlers, new SimpleAsyncQueue<Action<Exception>>(), null);
-
-            m_cancelationHandlers.Enqueue(handler);
-
-            if (IsCancellationRequested && m_cancelationHandlers.TryDequeue(out handler))
-                // TryDeque implies MemoryBarrier()
-                handler(m_cancelationReason);
-        }
-
-        public bool IsCancellationRequested {
-            get {
-                do {
-                    if (m_cancelRequest == CANCEL_NOT_REQUESTED)
-                        return false;
-                    if (m_cancelRequest == CANCEL_REQUESTED)
-                        return true;
-                    Thread.MemoryBarrier();
-                } while(true);
-            }
-        }
-
-        public Exception CancellationReason {
-            get {
-                do {
-                    Thread.MemoryBarrier();
-                } while(m_cancelRequest == CANCEL_REQUESTING);
-
-                return m_cancelationReason;
-            }
-        }
-
-        #region ICancellable implementation
-
-        public void Cancel() {
-            Cancel(null);
-        }
-
-        public void Cancel(Exception reason) {
-            if (CANCEL_NOT_REQUESTED == Interlocked.CompareExchange(ref m_cancelRequest, CANCEL_REQUESTING, CANCEL_NOT_REQUESTED)) {
-                m_cancelationReason = reason;
-                m_cancelRequest = CANCEL_REQUESTED;
-                if (m_cancelationHandlers != null) {
-                    Action<Exception> handler;
-                    while (m_cancelationHandlers.TryDequeue(out handler))
-                        handler(m_cancelationReason);
-                }
-            }
-        }
-
-        #endregion
     }
 }
 
diff --git a/Implab/AbstractPromise.cs b/Implab/AbstractPromise.cs
--- a/Implab/AbstractPromise.cs
+++ b/Implab/AbstractPromise.cs
@@ -3,28 +3,16 @@ using Implab.Parallels;
 
 namespace Implab {
     public abstract class AbstractPromise : AbstractEvent<AbstractPromise.HandlerDescriptor>, IPromise {
-        public struct HandlerDescriptor {
+        public class HandlerDescriptor {
             readonly Action m_handler;
             readonly Action<Exception> m_error;
-            readonly Action<Exception> m_cancel;
-            readonly PromiseEventType m_mask;
-
-            public HandlerDescriptor(Action success, Action<Exception> error, Action<Exception> cancel) {
+            public HandlerDescriptor(Action success, Action<Exception> error) {
                 m_handler = success;
                 m_error = error;
-                m_cancel = cancel;
-                m_mask = PromiseEventType.Success;
-            }
-
-            public HandlerDescriptor(Action handler, PromiseEventType mask) {
-                m_handler = handler;
-                m_error = null;
-                m_cancel = null;
-                m_mask = mask;
             }
 
             public void SignalSuccess() {
-                if ((m_mask & PromiseEventType.Success) != 0 && m_handler != null) {
+                if (m_handler != null) {
                     try {
                         m_handler();
                         // Analysis disable once EmptyGeneralCatchClause
@@ -40,28 +28,6 @@ namespace Implab {
                         // Analysis disable once EmptyGeneralCatchClause
                     } catch {
                     }
-                } else if ((m_mask & PromiseEventType.Error ) != 0 && m_handler != null) {
-                    try {
-                        m_handler();
-                        // Analysis disable once EmptyGeneralCatchClause
-                    } catch {
-                    }
-                }
-            }
-
-            public void SignalCancel(Exception reason) {
-                if (m_cancel != null) {
-                    try {
-                        m_cancel(reason);
-                        // Analysis disable once EmptyGeneralCatchClause
-                    } catch {
-                    }
-                } else if ( (m_mask & PromiseEventType.Cancelled) != 0 && m_handler != null) {
-                    try {
-                        m_handler();
-                        // Analysis disable once EmptyGeneralCatchClause
-                    } catch {
-                    }
                 }
             }
         }
@@ -75,48 +41,29 @@ namespace Implab {
                     handler.SignalSuccess();
                     break;
                 case REJECTED_STATE:
-                    handler.SignalError(Error);
-                    break;
-                case CANCELLED_STATE:
-                    handler.SignalCancel(CancellationReason);
+                    handler.SignalError(RejectReason);
                     break;
                 default:
                     throw new InvalidOperationException(String.Format("Invalid promise signal: {0}", signal));
             }
         }
 
-        protected override Signal GetResolveSignal() {
+        protected override Signal GetFulfillSignal() {
             var signal = new Signal();
-            On(signal.Set, PromiseEventType.All);
+            On(signal.Set, e => signal.Set());
             return signal;
         }
 
         #endregion
 
-        public Type PromiseType {
+        public Type ResultType {
             get {
                 return typeof(void);
             }
         }
 
-        public IPromise On(Action success, Action<Exception> error, Action<Exception> cancel) {
-            AddHandler(new HandlerDescriptor(success, error, cancel));
-            return this;
-        }
-
-        public IPromise On(Action success, Action<Exception> error) {
-            AddHandler(new HandlerDescriptor(success, error, null));
-            return this;
-        }
-
-        public IPromise On(Action success) {
-            AddHandler(new HandlerDescriptor(success, null, null));
-            return this;
-        }
-
-        public IPromise On(Action handler, PromiseEventType events) {
-            AddHandler(new HandlerDescriptor(handler,events));
-            return this;
+        public void On(Action success, Action<Exception> error) {
+            AddHandler(new HandlerDescriptor(success, error));
         }
 
         public IPromise<T> Cast<T>() {
diff --git a/Implab/AbstractPromiseT.cs b/Implab/AbstractPromiseT.cs
--- a/Implab/AbstractPromiseT.cs
+++ b/Implab/AbstractPromiseT.cs
@@ -84,7 +84,7 @@ namespace Implab {
             }
         }
 
-        public Type PromiseType {
+        public Type ResultType {
             get {
                 return typeof(T);
             }
@@ -167,7 +167,7 @@ namespace Implab {
 
         #region implemented abstract members of AbstractPromise
 
-        protected override Signal GetResolveSignal() {
+        protected override Signal GetFulfillSignal() {
             var signal = new Signal();
             AddHandler(new HandlerDescriptor(signal.Set, PromiseEventType.All));
             return signal;
@@ -179,7 +179,7 @@ namespace Implab {
                     handler.SignalSuccess(m_result);
                     break;
                 case REJECTED_STATE:
-                    handler.SignalError(Error);
+                    handler.SignalError(RejectReason);
                     break;
                 case CANCELLED_STATE:
                     handler.SignalCancel(CancellationReason);
diff --git a/Implab/FailedPromise.cs b/Implab/FailedPromise.cs
--- a/Implab/FailedPromise.cs
+++ b/Implab/FailedPromise.cs
@@ -53,20 +53,20 @@ namespace Implab {
         }
 
         public void Join() {
-            throw new TargetInvocationException(Error);
+            throw new TargetInvocationException(RejectReason);
         }
 
         public void Join(int timeout) {
-            throw new TargetInvocationException(Error);
+            throw new TargetInvocationException(RejectReason);
         }
 
-        public virtual Type PromiseType {
+        public virtual Type ResultType {
             get {
                 return typeof(void);
             }
         }
 
-        public bool IsResolved {
+        public bool IsFulfilled {
             get {
                 return true;
             }
@@ -78,7 +78,7 @@ namespace Implab {
             }
         }
 
-        public Exception Error {
+        public Exception RejectReason {
             get {
                 return m_error;
             }
diff --git a/Implab/FailedPromiseT.cs b/Implab/FailedPromiseT.cs
--- a/Implab/FailedPromiseT.cs
+++ b/Implab/FailedPromiseT.cs
@@ -9,7 +9,7 @@ namespace Implab {
         public IPromise<T> On(Action<T> success, Action<Exception> error, Action<Exception> cancel) {
             if (error != null) {
                 try {
-                    error(Error);  
+                    error(RejectReason);  
                     // Analysis disable once EmptyGeneralCatchClause
                 } catch {
                 }
@@ -20,7 +20,7 @@ namespace Implab {
         public IPromise<T> On(Action<T> success, Action<Exception> error) {
             if (error != null) {
                 try {
-                    error(Error);  
+                    error(RejectReason);  
                     // Analysis disable once EmptyGeneralCatchClause
                 } catch {
                 }
@@ -33,11 +33,11 @@ namespace Implab {
         }
 
         T IPromise<T>.Join() {
-            throw new TargetInvocationException(Error);
+            throw new TargetInvocationException(RejectReason);
         }
 
         T IPromise<T>.Join(int timeout) {
-            throw new TargetInvocationException(Error);
+            throw new TargetInvocationException(RejectReason);
         }
 
 
diff --git a/Implab/IPromise.cs b/Implab/IPromise.cs
--- a/Implab/IPromise.cs
+++ b/Implab/IPromise.cs
@@ -9,42 +9,29 @@ namespace Implab {
         /// <summary>
         /// Тип результата, получаемого через данное обещание.
         /// </summary>
-        Type PromiseType { get; }
+        Type ResultType { get; }
 
         /// <summary>
         /// Обещание является выполненым, либо успешно, либо с ошибкой, либо отменено.
         /// </summary>
-        bool IsResolved { get; }
+        bool IsFulfilled { get; }
 
-        /// <summary>
-        /// Обещание было отменено.
-        /// </summary>
-        bool IsCancelled { get; }
+        bool IsRejected { get; }
+
+        bool IsResolved { get; }
 
         /// <summary>
         /// Исключение возникшее в результате выполнения обещания, либо причина отмены.
         /// </summary>
-        Exception Error { get; }
+        Exception RejectReason { get; }
 
         /// <summary>
         /// Adds specified listeners to the current promise.
         /// </summary>
         /// <param name="success">The handler called on the successful promise completion.</param>
         /// <param name="error">The handler is called if an error while completing the promise occurred.</param>
-        /// <param name="cancel">The handler is called in case of promise cancellation.</param>
         /// <returns>The current promise.</returns>
-        IPromise On(Action success, Action<Exception> error, Action<Exception> cancel);
-        IPromise On(Action success, Action<Exception> error);
-        IPromise On(Action success);
-
-        /// <summary>
-        /// Adds specified listeners to the current promise.
-        /// </summary>
-        /// <param name="handler">The handler called on the specified events.</param>
-        /// <param name = "events">The combination of flags denoting the events for which the
-        /// handler shoud be called.</param>
-        /// <returns>The current promise.</returns>
-        IPromise On(Action handler, PromiseEventType events);
+        void On(Action success, Action<Exception> error);
 
         /// <summary>
         /// Преобразует результат обещания к заданному типу и возвращает новое обещание.
diff --git a/Implab/IPromiseT.cs b/Implab/IPromiseT.cs
--- a/Implab/IPromiseT.cs
+++ b/Implab/IPromiseT.cs
@@ -3,23 +3,10 @@
 namespace Implab {
     public interface IPromise<out T> : IPromise {
 
-        IPromise<T> On(Action<T> success, Action<Exception> error, Action<Exception> cancel);
-        
-        IPromise<T> On(Action<T> success, Action<Exception> error);
-
-        IPromise<T> On(Action<T> success);
+        void On(Action<T> success, Action<Exception> error);
 
         new T Join();
 
         new T Join(int timeout);
-
-        new IPromise<T> On(Action success, Action<Exception> error, Action<Exception> cancel);
-
-        new IPromise<T> On(Action success, Action<Exception> error);
-
-        new IPromise<T> On(Action success);
-
-        new IPromise<T> On(Action handler, PromiseEventType events);
-
     }
 }
diff --git a/Implab/Parallels/ArrayTraits.cs b/Implab/Parallels/ArrayTraits.cs
--- a/Implab/Parallels/ArrayTraits.cs
+++ b/Implab/Parallels/ArrayTraits.cs
@@ -164,7 +164,7 @@ namespace Implab.Parallels {
             // Analysis disable AccessToDisposedClosure
             AsyncPool.RunThread<int>(() => {
                 for (int i = 0; i < source.Length; i++) {
-                    if(promise.IsResolved)
+                    if(promise.IsFulfilled)
                         break; // stop processing in case of error or cancellation
                     var idx = i;
 
diff --git a/Implab/Parallels/SimpleAsyncQueue.cs b/Implab/Parallels/SimpleAsyncQueue.cs
--- a/Implab/Parallels/SimpleAsyncQueue.cs
+++ b/Implab/Parallels/SimpleAsyncQueue.cs
@@ -15,12 +15,12 @@ namespace Implab.Parallels {
 
         // the reader and the writer are mainteined completely independent,
         // the reader can read next item when m_first.next is not null
-        // the writer creates the a new node, moves m_last to this node and
+        // the writer creates a new node, moves m_last to this node and
         // only after that restores the reference from the previous node
-        // making available the reader to read the new node.
+        // making the reader be able to read the new node.
 
-        Node m_first; // position on the node which is already read
-        Node m_last; // position on the node which is already written
+        volatile Node m_first; // position on the node which is already read
+        volatile Node m_last; // position on the node which is already written
 
         public SimpleAsyncQueue() {
             m_first = m_last = new Node(default(T));
@@ -35,29 +35,38 @@ namespace Implab.Parallels {
 
             // release-fence
             last.next = next;
-            
+
         }
 
         public bool TryDequeue(out T value) {
-            Node first;
-            Node next;
+            Node first = m_first; ;
+            Node next = first.next; ;
+
+            if (next == null) {
+                value = default(T);
+                return false;
+            }
+
+            var first2 = Interlocked.CompareExchange(ref m_first, next, first);
+
+            if (first != first2) {
+                // head is updated by someone else
 
-            Thread.MemoryBarrier(); // ensure m_first is fresh
-            SpinWait spin = new SpinWait();
-            do {
-                first = m_first;
-                // aquire-fence
-                next = first.next;
-                if (next == null) {
-                    value = default(T);
-                    return false;
-                }
-                
-                if (first == Interlocked.CompareExchange(ref m_first, next, first))
-                    // head succesfully updated
-                    break;
-                spin.SpinOnce();
-            } while (true);
+                SpinWait spin = new SpinWait();
+                do {
+                    first = first2;
+                    next = first.next;
+                    if (next == null) {
+                        value = default(T);
+                        return false;
+                    }
+
+                    first2 = Interlocked.CompareExchange(ref m_first, next, first);
+                    if (first == first2)
+                        break;
+                    spin.SpinOnce();
+                } while (true);
+            }
 
             value = next.value;
             return true;
diff --git a/Implab/PromiseAwaiter.cs b/Implab/PromiseAwaiter.cs
--- a/Implab/PromiseAwaiter.cs
+++ b/Implab/PromiseAwaiter.cs
@@ -20,7 +20,7 @@ namespace Implab {
 
         public bool IsCompleted {
             get {
-                return m_promise.IsResolved;
+                return m_promise.IsFulfilled;
             }
         }
     }
diff --git a/Implab/PromiseAwaiterT.cs b/Implab/PromiseAwaiterT.cs
--- a/Implab/PromiseAwaiterT.cs
+++ b/Implab/PromiseAwaiterT.cs
@@ -20,7 +20,7 @@ namespace Implab {
 
         public bool IsCompleted {
             get {
-                return m_promise.IsResolved;
+                return m_promise.IsFulfilled;
             }
         }
     }
diff --git a/Implab/SuccessPromise.cs b/Implab/SuccessPromise.cs
--- a/Implab/SuccessPromise.cs
+++ b/Implab/SuccessPromise.cs
@@ -58,13 +58,13 @@ namespace Implab {
         public void Join(int timeout) {
         }
 
-        public Type PromiseType {
+        public Type ResultType {
             get {
                 return typeof(void);
             }
         }
 
-        public bool IsResolved {
+        public bool IsFulfilled {
             get {
                 return true;
             }
@@ -76,7 +76,7 @@ namespace Implab {
             }
         }
 
-        public Exception Error {
+        public Exception RejectReason {
             get {
                 return null;
             }
diff --git a/Implab/SuccessPromiseT.cs b/Implab/SuccessPromiseT.cs
--- a/Implab/SuccessPromiseT.cs
+++ b/Implab/SuccessPromiseT.cs
@@ -119,13 +119,13 @@ namespace Implab {
         void IPromise.Join(int timeout) {
         }
 
-        public Type PromiseType {
+        public Type ResultType {
             get {
                 return typeof(T);
             }
         }
 
-        public bool IsResolved {
+        public bool IsFulfilled {
             get {
                 return true;
             }
@@ -137,7 +137,7 @@ namespace Implab {
             }
         }
 
-        public Exception Error {
+        public Exception RejectReason {
             get {
                 return null;
             }
diff --git a/packages/repositories.config b/packages/repositories.config
--- a/packages/repositories.config
+++ b/packages/repositories.config
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <repositories>
   <repository path="../Implab.Test/Implab.Format.Test/packages.config" />
+  <repository path="../Implab.Test/packages.config" />
   <repository path="../MonoPlay/packages.config" />
 </repositories>
\ No newline at end of file