81 lines
2.5 KiB
C#
81 lines
2.5 KiB
C#
//
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// TaskCompletionQueue.cs
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//
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// Authors:
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// Jérémie Laval <jeremie dot laval at xamarin dot com>
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//
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// Copyright 2011 Xamarin Inc (http://www.xamarin.com).
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//
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//
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#if NET_4_0
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using System;
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using System.Threading;
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using System.Collections.Generic;
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using System.Collections.Concurrent;
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namespace System.Threading.Tasks
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{
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internal struct TaskCompletionQueue<TCompletion> where TCompletion : class
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{
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TCompletion single;
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ConcurrentOrderedList<TCompletion> completed;
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public void Add (TCompletion continuation)
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{
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if (single == null && Interlocked.CompareExchange (ref single, continuation, null) == null)
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return;
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if (completed == null)
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Interlocked.CompareExchange (ref completed, new ConcurrentOrderedList<TCompletion> (), null);
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completed.TryAdd (continuation);
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}
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public bool Remove (TCompletion continuation)
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{
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TCompletion temp = single;
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if (temp != null && temp == continuation && Interlocked.CompareExchange (ref single, null, continuation) == continuation)
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return true;
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if (completed != null)
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return completed.TryRemove (continuation);
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return false;
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}
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public bool HasElements {
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get {
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return single != null || (completed != null && completed.Count != 0);
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}
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}
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public bool TryGetNextCompletion (out TCompletion continuation)
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{
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continuation = null;
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if (single != null && (continuation = Interlocked.Exchange (ref single, null)) != null)
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return true;
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return completed != null && completed.TryPop (out continuation);
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}
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}
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}
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#endif
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