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//
// TaskAwaiter.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;
using System.Runtime.ExceptionServices;
namespace System.Runtime.CompilerServices
{
public struct TaskAwaiter : ICriticalNotifyCompletion
{
readonly Task task;
internal TaskAwaiter (Task task)
{
this.task = task;
}
public bool IsCompleted {
get {
return task.IsCompleted;
}
}
public void GetResult ()
{
if (!task.IsCompleted)
task.WaitCore (Timeout.Infinite, CancellationToken.None);
if (task.Status != TaskStatus.RanToCompletion)
// Merge current and dispatched stack traces if there is any
ExceptionDispatchInfo.Capture (HandleUnexpectedTaskResult (task)).Throw ();
}
internal static Exception HandleUnexpectedTaskResult (Task task)
{
switch (task.Status) {
case TaskStatus.Canceled:
return new TaskCanceledException (task);
case TaskStatus.Faulted:
return task.Exception.InnerException;
default:
throw new ArgumentException ("Should never be reached");
}
}
internal static void HandleOnCompleted (Task task, Action continuation, bool continueOnSourceContext, bool manageContext)
{
if (continueOnSourceContext && SynchronizationContext.Current != null) {
task.ContinueWith (new SynchronizationContextContinuation (continuation, SynchronizationContext.Current));
} else {
task.ContinueWith (new ActionContinuation (continuation));
}
}
public void OnCompleted (Action continuation)
{
if (continuation == null)
throw new ArgumentNullException ("continuation");
HandleOnCompleted (task, continuation, true, true);
}
public void UnsafeOnCompleted (Action continuation)
{
if (continuation == null)
throw new ArgumentNullException ("continuation");
HandleOnCompleted (task, continuation, true, false);
}
}
}
#endif
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