2 // AsyncTaskMethodBuilder.cs
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;
35 namespace System.Runtime.CompilerServices
37 public struct AsyncTaskMethodBuilder
39 readonly Task<object> task;
40 IAsyncStateMachine stateMachine;
42 private AsyncTaskMethodBuilder (Task<object> task)
45 this.stateMachine = null;
54 public void AwaitOnCompleted<TAwaiter, TStateMachine> (ref TAwaiter awaiter, ref TStateMachine stateMachine)
55 where TAwaiter : INotifyCompletion
56 where TStateMachine : IAsyncStateMachine
58 var action = new Action (stateMachine.MoveNext);
59 awaiter.OnCompleted (action);
62 public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine> (ref TAwaiter awaiter, ref TStateMachine stateMachine)
63 where TAwaiter : ICriticalNotifyCompletion
64 where TStateMachine : IAsyncStateMachine
66 var action = new Action (stateMachine.MoveNext);
67 awaiter.UnsafeOnCompleted (action);
70 public static AsyncTaskMethodBuilder Create ()
72 var task = new Task<object> (TaskActionInvoker.Empty, null, CancellationToken.None, TaskCreationOptions.None, null);
73 task.SetupScheduler (TaskScheduler.Current);
74 return new AsyncTaskMethodBuilder (task);
77 public void SetException (Exception exception)
79 if (exception is OperationCanceledException) {
80 if (Task.TrySetCanceled ())
83 if (Task.TrySetException (new AggregateException (exception)))
87 throw new InvalidOperationException ("The task has already completed");
90 public void SetStateMachine (IAsyncStateMachine stateMachine)
92 if (stateMachine == null)
93 throw new ArgumentNullException ("stateMachine");
95 if (this.stateMachine != null)
96 throw new InvalidOperationException ("The state machine was previously set");
98 this.stateMachine = stateMachine;
101 public void SetResult ()
103 if (!task.TrySetResult (null))
104 throw new InvalidOperationException ("The task has already completed");
107 public void Start<TStateMachine> (ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine
109 if (stateMachine == null)
110 throw new ArgumentNullException ("stateMachine");
112 stateMachine.MoveNext ();