TaskCompletionSource.cs

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// 
// TaskCompletionSource.cs
//  
// Authors:
//       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
//       Marek Safar <marek.safar@gmail.com>
// 
// Copyright (c) 2009 Jérémie "Garuma" Laval
// Copyright 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_0
using System;
using System.Collections.Generic;

namespace System.Threading.Tasks
{
    public class TaskCompletionSource<TResult>
    {
        readonly Task<TResult> source;

        public TaskCompletionSource ()
            : this (null, TaskCreationOptions.None)
        {
        }
        
        public TaskCompletionSource (object state)
            : this (state, TaskCreationOptions.None)
        {
        }
        
        public TaskCompletionSource (TaskCreationOptions creationOptions)
            : this (null, creationOptions)
        {
        }
        
        public TaskCompletionSource (object state, TaskCreationOptions creationOptions)
        {
            if ((creationOptions & System.Threading.Tasks.Task.WorkerTaskNotSupportedOptions) != 0)
                throw new ArgumentOutOfRangeException ("creationOptions");

            source = new Task<TResult> (TaskActionInvoker.Empty, state, CancellationToken.None, creationOptions, null);
            source.SetupScheduler (TaskScheduler.Current);
        }
        
        public void SetCanceled ()
        {
            if (!TrySetCanceled ())
                ThrowInvalidException ();
        }
        
        public void SetException (Exception exception)
        {
            if (exception == null)
                throw new ArgumentNullException ("exception");
            
            SetException (new Exception[] { exception });
        }
        
        public void SetException (IEnumerable<Exception> exceptions)
        {
            if (!TrySetException (exceptions))
                ThrowInvalidException ();
        }
        
        public void SetResult (TResult result)
        {
            if (!TrySetResult (result))
                ThrowInvalidException ();
        }
                
        static void ThrowInvalidException ()
        {
            throw new InvalidOperationException ("The underlying Task is already in one of the three final states: RanToCompletion, Faulted, or Canceled.");
        }
        
        public bool TrySetCanceled ()
        {
            return source.TrySetCanceled ();
        }
        
        public bool TrySetException (Exception exception)
        {
            if (exception == null)
                throw new ArgumentNullException ("exception");
            
            return TrySetException (new Exception[] { exception });
        }
        
        public bool TrySetException (IEnumerable<Exception> exceptions)
        {
            if (exceptions == null)
                throw new ArgumentNullException ("exceptions");

            var aggregate = new AggregateException (exceptions);
            if (aggregate.InnerExceptions.Count == 0)
                throw new ArgumentNullException ("exceptions");

            return source.TrySetException (aggregate);
        }
        
        public bool TrySetResult (TResult result)
        {
            return source.TrySetResult (result);
        }

        public Task<TResult> Task {
            get {
                return source;
            }
        }
    }
}
#endif