5 // Marek Safar <marek.safar@gmail.com>
7 // Copyright (C) 2011 Novell, Inc (http://www.novell.com)
8 // Copyright (C) 2011 Xamarin, Inc (http://www.xamarin.com)
10 // Permission is hereby granted, free of charge, to any person obtaining
11 // a copy of this software and associated documentation files (the
12 // "Software"), to deal in the Software without restriction, including
13 // without limitation the rights to use, copy, modify, merge, publish,
14 // distribute, sublicense, and/or sell copies of the Software, and to
15 // permit persons to whom the Software is furnished to do so, subject to
16 // the following conditions:
18 // The above copyright notice and this permission notice shall be
19 // included in all copies or substantial portions of the Software.
21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
32 using System.Threading;
33 using System.Threading.Tasks;
34 using System.Runtime.ExceptionServices;
36 namespace System.Runtime.CompilerServices
38 public struct TaskAwaiter : ICriticalNotifyCompletion
42 internal TaskAwaiter (Task task)
47 public bool IsCompleted {
49 return task.IsCompleted;
53 public void GetResult ()
55 if (!task.IsCompleted)
56 task.WaitCore (Timeout.Infinite, CancellationToken.None, true);
58 if (task.Status != TaskStatus.RanToCompletion)
59 // Merge current and dispatched stack traces if there is any
60 ExceptionDispatchInfo.Capture (HandleUnexpectedTaskResult (task)).Throw ();
63 internal static Exception HandleUnexpectedTaskResult (Task task)
65 switch (task.Status) {
66 case TaskStatus.Canceled:
67 return new TaskCanceledException (task);
68 case TaskStatus.Faulted:
69 return task.Exception.InnerException;
71 throw new ArgumentException (string.Format ("Unexpected task `{0}' status `{1}'", task.Id, task.Status));
75 internal static void HandleOnCompleted (Task task, Action continuation, bool continueOnSourceContext, bool manageContext)
77 if (continueOnSourceContext && SynchronizationContext.Current != null) {
78 task.ContinueWith (new SynchronizationContextContinuation (continuation, SynchronizationContext.Current));
81 if (TaskScheduler.Current != TaskScheduler.Default) {
82 var runner = new Task (TaskActionInvoker.Create (continuation), null, CancellationToken.None, TaskCreationOptions.None, null);
83 runner.SetupScheduler (TaskScheduler.Current);
84 cont = new SchedulerAwaitContinuation (runner);
86 cont = new ActionContinuation (continuation);
89 task.ContinueWith (cont);
93 public void OnCompleted (Action continuation)
95 if (continuation == null)
96 throw new ArgumentNullException ("continuation");
98 HandleOnCompleted (task, continuation, true, true);
101 public void UnsafeOnCompleted (Action continuation)
103 if (continuation == null)
104 throw new ArgumentNullException ("continuation");
106 HandleOnCompleted (task, continuation, true, false);