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//
// AsyncTaskMethodBuilder_T.cs
//
// Authors:
// Marek Safar <marek.safar@gmail.com>
//
// Copyright (C) 2011 Novell, Inc (http://www.novell.com)
// Copyright (C) 2011 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 in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
#if NET_4_5
using System.Threading;
using System.Threading.Tasks;
namespace System.Runtime.CompilerServices
{
public struct AsyncTaskMethodBuilder<TResult>
{
readonly Task<TResult> task;
IAsyncStateMachine stateMachine;
private AsyncTaskMethodBuilder (Task<TResult> task)
{
this.task = task;
this.stateMachine = null;
}
public Task<TResult> Task {
get {
return task;
}
}
public void AwaitOnCompleted<TAwaiter, TStateMachine> (ref TAwaiter awaiter, ref TStateMachine stateMachine)
where TAwaiter : INotifyCompletion
where TStateMachine : IAsyncStateMachine
{
var action = new Action (stateMachine.MoveNext);
awaiter.OnCompleted (action);
}
public void AwaitUnsafeOnCompleted<TAwaiter, TStateMachine> (ref TAwaiter awaiter, ref TStateMachine stateMachine)
where TAwaiter : ICriticalNotifyCompletion
where TStateMachine : IAsyncStateMachine
{
var action = new Action (stateMachine.MoveNext);
awaiter.UnsafeOnCompleted (action);
}
public static AsyncTaskMethodBuilder<TResult> Create ()
{
var task = new Task<TResult> (TaskActionInvoker.Empty, null, CancellationToken.None, TaskCreationOptions.None, null);
task.SetupScheduler (TaskScheduler.Current);
return new AsyncTaskMethodBuilder<TResult> (task);
}
public void SetException (Exception exception)
{
if (exception is OperationCanceledException) {
if (Task.TrySetCanceled ())
return;
} else {
if (Task.TrySetException (new AggregateException (exception)))
return;
}
throw new InvalidOperationException ("The task has already completed");
}
public void SetStateMachine (IAsyncStateMachine stateMachine)
{
if (stateMachine == null)
throw new ArgumentNullException ("stateMachine");
if (this.stateMachine != null)
throw new InvalidOperationException ("The state machine was previously set");
this.stateMachine = stateMachine;
}
public void SetResult (TResult result)
{
if (!task.TrySetResult (result))
throw new InvalidOperationException ("The task has already completed");
}
public void Start<TStateMachine> (ref TStateMachine stateMachine) where TStateMachine : IAsyncStateMachine
{
if (stateMachine == null)
throw new ArgumentNullException ("stateMachine");
stateMachine.MoveNext ();
}
}
}
#endif
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