//
// TaskAwaiter_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;
using System.Runtime.ExceptionServices;

namespace System.Runtime.CompilerServices
{
	public struct TaskAwaiter<TResult> : ICriticalNotifyCompletion
	{
		readonly Task<TResult> task;

		internal TaskAwaiter (Task<TResult> task)
		{
			this.task = task;
		}

		public bool IsCompleted {
			get {
				return task.IsCompleted;
			}
		}

		public TResult GetResult ()
		{
			if (!task.IsCompleted)
				task.WaitCore (Timeout.Infinite, CancellationToken.None);

			if (task.Status != TaskStatus.RanToCompletion)
				ExceptionDispatchInfo.Capture (TaskAwaiter.HandleUnexpectedTaskResult (task)).Throw ();

			return task.Result;
		}

		public void OnCompleted (Action continuation)
		{
			if (continuation == null)
				throw new ArgumentNullException ("continuation");

			TaskAwaiter.HandleOnCompleted (task, continuation, true, true);
		}

		public void UnsafeOnCompleted (Action continuation)
		{
			if (continuation == null)
				throw new ArgumentNullException ("continuation");

			TaskAwaiter.HandleOnCompleted (task, continuation, true, false);
		}
	}
}

#endif