Synnefo » Pithos MS Client

#region

/* -----------------------------------------------------------------------

 * <copyright file="AsyncManualResetEvent.cs" company="GRNet">

 * 

 * Copyright 2011-2012 GRNET S.A. All rights reserved.

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 * Redistribution and use in source and binary forms, with or

 * without modification, are permitted provided that the following

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 *   1. Redistributions of source code must retain the above

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 *      disclaimer.

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 *   2. Redistributions in binary form must reproduce the above

 *      copyright notice, this list of conditions and the following

 *      disclaimer in the documentation and/or other materials

 *      provided with the distribution.

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 *

 * THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS

 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

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 * </copyright>

 * -----------------------------------------------------------------------

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#endregion

using System.Threading;

using System.Threading.Tasks;

namespace Pithos.Core.Agents

{

    using System;

    using System.Collections.Generic;

    using System.Linq;

    using System.Text;

    /// <summary>

    /// TODO: Update summary.

    /// </summary>

    public class AsyncManualResetEvent

    {

        private volatile TaskCompletionSource<bool> _tcs;

        public AsyncManualResetEvent()

        {

            _tcs = new TaskCompletionSource<bool>();

        }

        public AsyncManualResetEvent(bool signalled)

        {            

            _tcs = new TaskCompletionSource<bool>();

            if (signalled)

                _tcs.SetResult(true);

        }

        public Task WaitAsync() { return _tcs.Task; }

        public void Wait()

        {            

            _tcs.Task.Wait();

        }

        public void Set()

        {

            var tcs = _tcs;

            Task.Factory.StartNew(s => ((TaskCompletionSource<bool>)s).TrySetResult(true),

                tcs, CancellationToken.None, TaskCreationOptions.PreferFairness, TaskScheduler.Default);

            tcs.Task.Wait(); 

        }

        public void Reset()

        {

            while (true)

            {

                var tcs = _tcs;

                if (!tcs.Task.IsCompleted)

                    return;

#pragma warning disable 420

                if (Interlocked.CompareExchange(ref _tcs, new TaskCompletionSource<bool>(), tcs) == tcs)

#pragma warning restore 420

                    return;

            }

        }

    }

}