Merge pull request #799 from kebby/master
[mono.git] / mcs / class / corlib / System.Threading.Tasks / Task.cs
index e040c339564001314057f11a2289858db08c88d0..5eefcb7da5f87592bc67d2751e579f0b95ed1055 100644 (file)
@@ -6,7 +6,7 @@
 //    Jérémie Laval <jeremie dot laval at xamarin dot com>
 //
 // Copyright (c) 2008 Jérémie "Garuma" Laval
-// Copyright 2011 Xamarin Inc (http://www.xamarin.com).
+// Copyright 2011-2013 Xamarin Inc (http://www.xamarin.com).
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
@@ -46,13 +46,11 @@ namespace System.Threading.Tasks
                // and for Parent property.
                [System.ThreadStatic]
                static Task current;
-               [System.ThreadStatic]
-               static Action<Task> childWorkAdder;
                
                // parent is the outer task in which this task is created
                readonly Task parent;
-               // contAncestor is the Task on which this continuation was setup
-               readonly Task contAncestor;
+               // A reference to a Task on which this continuation is attached to
+               Task contAncestor;
                
                static int          id = -1;
                static readonly TaskFactory defaultFactory = new TaskFactory ();
@@ -65,6 +63,7 @@ namespace System.Threading.Tasks
                internal TaskScheduler       scheduler;
 
                TaskExceptionSlot exSlot;
+               ManualResetEvent wait_handle;
 
                TaskStatus          status;
 
@@ -150,10 +149,10 @@ namespace System.Threading.Tasks
 
                        // Process creationOptions
 #if NET_4_5
-                       if (HasFlag (creationOptions, TaskCreationOptions.AttachedToParent)
-                           && parent != null && !HasFlag (parent.CreationOptions, TaskCreationOptions.DenyChildAttach))
+                       if (parent != null && HasFlag (creationOptions, TaskCreationOptions.AttachedToParent)
+                           && !HasFlag (parent.CreationOptions, TaskCreationOptions.DenyChildAttach))
 #else
-                       if (HasFlag (creationOptions, TaskCreationOptions.AttachedToParent) && parent != null)
+                       if (parent != null && HasFlag (creationOptions, TaskCreationOptions.AttachedToParent))
 #endif
                                parent.AddChild ();
 
@@ -206,8 +205,15 @@ namespace System.Threading.Tasks
                        if (Status > TaskStatus.WaitingForActivation)
                                throw new InvalidOperationException ("The task is not in a valid state to be started");
 
+                       if (IsContinuation)
+                               throw new InvalidOperationException ("RunSynchronously may not be called on a continuation task");
+
+                       RunSynchronouslyCore (scheduler);
+               }
+
+               internal void RunSynchronouslyCore (TaskScheduler scheduler)
+               {
                        SetupScheduler (scheduler);
-                       var saveStatus = status;
                        Status = TaskStatus.WaitingToRun;
 
                        try {
@@ -217,8 +223,7 @@ namespace System.Threading.Tasks
                                throw new TaskSchedulerException (inner);
                        }
 
-                       Status = saveStatus;
-                       Start (scheduler);
+                       Schedule ();
                        Wait ();
                }
                #endregion
@@ -339,7 +344,7 @@ namespace System.Threading.Tasks
                                continuation.Execute ();
                }
 
-               void RemoveContinuation (IContinuation continuation)
+               internal void RemoveContinuation (IContinuation continuation)
                {
                        continuations.Remove (continuation);
                }
@@ -362,18 +367,7 @@ namespace System.Threading.Tasks
                internal void Schedule ()
                {
                        Status = TaskStatus.WaitingToRun;
-                       
-                       // If worker is null it means it is a local one, revert to the old behavior
-                       // If TaskScheduler.Current is not being used, the scheduler was explicitly provided, so we must use that
-                       if (scheduler != TaskScheduler.Current || childWorkAdder == null || HasFlag (creationOptions, TaskCreationOptions.PreferFairness)) {
-                               scheduler.QueueTask (this);
-                       } else {
-                               /* Like the semantic of the ABP paper describe it, we add ourselves to the bottom 
-                                * of our Parent Task's ThreadWorker deque. It's ok to do that since we are in
-                                * the correct Thread during the creation
-                                */
-                               childWorkAdder (this);
-                       }
+                       scheduler.QueueTask (this);
                }
                
                void ThreadStart ()
@@ -494,7 +488,11 @@ namespace System.Threading.Tasks
                                ProcessChildExceptions ();
                                Status = exSlot == null ? TaskStatus.RanToCompletion : TaskStatus.Faulted;
                                ProcessCompleteDelegates ();
-                               if (HasFlag (creationOptions, TaskCreationOptions.AttachedToParent) && parent != null)
+                               if (parent != null &&
+#if NET_4_5
+                                   !HasFlag (parent.CreationOptions, TaskCreationOptions.DenyChildAttach) &&
+#endif
+                                       HasFlag (creationOptions, TaskCreationOptions.AttachedToParent))
                                        parent.ChildCompleted (this.Exception);
                        }
                }
@@ -502,7 +500,9 @@ namespace System.Threading.Tasks
                void InnerInvoke ()
                {
                        if (IsContinuation) {
-                               invoker.Invoke (contAncestor, state, this);
+                               var ancestor = contAncestor;
+                               contAncestor = null;
+                               invoker.Invoke (ancestor, state, this);
                        } else {
                                invoker.Invoke (this, state, this);
                        }
@@ -524,6 +524,18 @@ namespace System.Threading.Tasks
                                        Status = TaskStatus.WaitingForChildrenToComplete;
                        }
 
+                       if (wait_handle != null)
+                               wait_handle.Set ();
+
+                       // Tell parent that we are finished
+                       if (parent != null && HasFlag (creationOptions, TaskCreationOptions.AttachedToParent) &&
+#if NET_4_5
+                           !HasFlag (parent.CreationOptions, TaskCreationOptions.DenyChildAttach) &&
+#endif
+                               status != TaskStatus.WaitingForChildrenToComplete) {
+                               parent.ChildCompleted (this.Exception);
+                       }
+
                        // Completions are already processed when task is canceled or faulted
                        if (status == TaskStatus.RanToCompletion)
                                ProcessCompleteDelegates ();
@@ -536,11 +548,6 @@ namespace System.Threading.Tasks
 
                        if (cancellationRegistration.HasValue)
                                cancellationRegistration.Value.Dispose ();
-                       
-                       // Tell parent that we are finished
-                       if (HasFlag (creationOptions, TaskCreationOptions.AttachedToParent) && parent != null && status != TaskStatus.WaitingForChildrenToComplete) {
-                               parent.ChildCompleted (this.Exception);
-                       }
                }
 
                void ProcessCompleteDelegates ()
@@ -576,6 +583,10 @@ namespace System.Threading.Tasks
                internal void CancelReal ()
                {
                        Status = TaskStatus.Canceled;
+
+                       if (wait_handle != null)
+                               wait_handle.Set ();
+
                        ProcessCompleteDelegates ();
                }
 
@@ -589,6 +600,10 @@ namespace System.Threading.Tasks
                        ExceptionSlot.Exception = e;
                        Thread.MemoryBarrier ();
                        Status = TaskStatus.Faulted;
+
+                       if (wait_handle != null)
+                               wait_handle.Set ();
+
                        ProcessCompleteDelegates ();
                }
 
@@ -626,25 +641,7 @@ namespace System.Threading.Tasks
                        if (millisecondsTimeout < -1)
                                throw new ArgumentOutOfRangeException ("millisecondsTimeout");
 
-                       bool result = true;
-
-                       if (!IsCompleted) {
-                               // If the task is ready to be run and we were supposed to wait on it indefinitely without cancellation, just run it
-                               if (Status == TaskStatus.WaitingToRun && millisecondsTimeout == Timeout.Infinite && scheduler != null && !cancellationToken.CanBeCanceled)
-                                       scheduler.RunInline (this, true);
-
-                               if (!IsCompleted) {
-                                       var continuation = new ManualResetContinuation ();
-                                       try {
-                                               ContinueWith (continuation);
-                                               result = continuation.Event.Wait (millisecondsTimeout, cancellationToken);
-                                       } finally {
-                                               if (!result)
-                                                       RemoveContinuation (continuation);
-                                               continuation.Dispose ();
-                                       }
-                               }
-                       }
+                       bool result = WaitCore (millisecondsTimeout, cancellationToken);
 
                        if (IsCanceled)
                                throw new AggregateException (new TaskCanceledException (this));
@@ -653,8 +650,31 @@ namespace System.Threading.Tasks
                        if (exception != null)
                                throw exception;
 
-                       if (childTasks != null)
-                               childTasks.Wait ();
+                       return result;
+               }
+
+               internal bool WaitCore (int millisecondsTimeout, CancellationToken cancellationToken)
+               {
+                       if (IsCompleted)
+                               return true;
+
+                       // If the task is ready to be run and we were supposed to wait on it indefinitely without cancellation, just run it
+                       if (Status == TaskStatus.WaitingToRun && millisecondsTimeout == Timeout.Infinite && scheduler != null && !cancellationToken.CanBeCanceled)
+                               scheduler.RunInline (this, true);
+
+                       bool result = true;
+
+                       if (!IsCompleted) {
+                               var continuation = new ManualResetContinuation ();
+                               try {
+                                       ContinueWith (continuation);
+                                       result = continuation.Event.Wait (millisecondsTimeout, cancellationToken);
+                               } finally {
+                                       if (!result)
+                                               RemoveContinuation (continuation);
+                                       continuation.Dispose ();
+                               }
+                       }
 
                        return result;
                }
@@ -808,7 +828,7 @@ namespace System.Threading.Tasks
                #region Dispose
                public void Dispose ()
                {
-                       Dispose (true);
+                       Dispose (true);                 
                }
                
                protected virtual void Dispose (bool disposing)
@@ -823,6 +843,8 @@ namespace System.Threading.Tasks
                                state = null;
                                if (cancellationRegistration != null)
                                        cancellationRegistration.Value.Dispose ();
+                               if (wait_handle != null)
+                                       wait_handle.Dispose ();
                        }
                }
                #endregion
@@ -937,11 +959,23 @@ namespace System.Threading.Tasks
                        if (millisecondsDelay < -1)
                                throw new ArgumentOutOfRangeException ("millisecondsDelay");
 
-                       var task = new Task (TaskActionInvoker.Delay, millisecondsDelay, cancellationToken, TaskCreationOptions.None, null, TaskConstants.Finished);
-                       task.SetupScheduler (TaskScheduler.Current);
-                       
-                       if (millisecondsDelay != Timeout.Infinite)
-                               task.scheduler.QueueTask (task);
+                       if (cancellationToken.IsCancellationRequested)
+                               return TaskConstants.Canceled;
+
+                       var task = new Task (TaskActionInvoker.Empty, null, cancellationToken, TaskCreationOptions.None, null, null);
+                       task.SetupScheduler (TaskScheduler.Default);
+
+                       if (millisecondsDelay != Timeout.Infinite) {
+                               var timer = new Timer (delegate (object state) {
+                                       var t = (Task) state;
+                                       if (t.Status == TaskStatus.WaitingForActivation) {
+                                               t.Status = TaskStatus.Running;
+                                               t.Finish ();
+                                       }
+                               }, task, millisecondsDelay, -1);
+
+                               task.ContinueWith (new DisposeContinuation (timer));
+                       }
 
                        return task;
                }
@@ -1048,6 +1082,9 @@ namespace System.Threading.Tasks
 
                internal static Task<TResult[]> WhenAllCore<TResult> (IList<Task<TResult>> tasks)
                {
+                       if (tasks.Count == 0)
+                               return FromResult(new TResult[0]);
+
                        foreach (var t in tasks) {
                                if (t == null)
                                        throw new ArgumentException ("tasks", "the tasks argument contains a null element");
@@ -1272,7 +1309,13 @@ namespace System.Threading.Tasks
 
                WaitHandle IAsyncResult.AsyncWaitHandle {
                        get {
-                               return null;
+                               if (invoker == null)
+                                       throw new ObjectDisposedException (GetType ().ToString ());
+
+                               if (wait_handle == null)
+                                       Interlocked.CompareExchange (ref wait_handle, new ManualResetEvent (IsCompleted), null);
+
+                               return wait_handle;
                        }
                }