132 lines
4.0 KiB
C#
132 lines
4.0 KiB
C#
//
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// ParallelEnumerator.cs
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//
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// Author:
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// Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
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//
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// Copyright (c) 2010 Jérémie "Garuma" Laval
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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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#if NET_4_0
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using System;
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using System.Threading;
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using System.Collections;
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using System.Collections.Generic;
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using System.Collections.Concurrent;
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using System.Linq.Parallel.QueryNodes;
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namespace System.Linq.Parallel
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{
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internal class ParallelQueryEnumerator<T> : IEnumerator<T>
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{
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readonly int DefaultBufferSize = ParallelExecuter.GetBestWorkerNumber () * 50;
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BlockingCollection<T> buffer;
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IEnumerator<T> loader;
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QueryOptions options;
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OrderingEnumerator<T> ordEnumerator;
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T current;
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Action waitAction;
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internal ParallelQueryEnumerator (QueryBaseNode<T> node)
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{
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this.options = ParallelExecuter.CheckQuery (node);
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if (options.ShouldBeSequential && options.Mode != ParallelExecutionMode.ForceParallelism) {
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IEnumerable<T> buffer = node.GetSequential ();
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loader = buffer.GetEnumerator ();
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} else {
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Setup ();
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// Launch adding to the buffer asynchronously via Tasks
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if (options.BehindOrderGuard.Value) {
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waitAction = ParallelExecuter.ProcessAndCallback (node,
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ordEnumerator.Add,
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ordEnumerator.EndParticipation,
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ordEnumerator.Stop,
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options);
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} else {
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waitAction = ParallelExecuter.ProcessAndCallback (node,
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buffer.Add,
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buffer.CompleteAdding,
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options);
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}
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if (options.Options.HasValue && options.Options.Value == ParallelMergeOptions.FullyBuffered)
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waitAction ();
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}
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}
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void Setup ()
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{
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if (!options.BehindOrderGuard.Value) {
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if (options.Options.HasValue && (options.Options.Value == ParallelMergeOptions.NotBuffered
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|| options.Options.Value == ParallelMergeOptions.FullyBuffered)) {
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buffer = new BlockingCollection<T> ();
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} else {
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buffer = new BlockingCollection<T> (DefaultBufferSize);
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}
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IEnumerable<T> source = buffer.GetConsumingEnumerable (options.MergedToken);
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loader = source.GetEnumerator ();
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} else {
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loader = ordEnumerator = new OrderingEnumerator<T> (options.PartitionCount, options.MergedToken);
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}
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}
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public void Dispose ()
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{
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}
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public void Reset ()
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{
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throw new NotSupportedException ();
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}
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public bool MoveNext ()
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{
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// If there are no stuff in the buffer
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// but CompleteAdding hasn't been called,
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// MoveNext blocks until further results are produced
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if (!loader.MoveNext ())
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return false;
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current = loader.Current;
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return true;
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}
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public T Current {
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get {
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return current;
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}
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}
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object IEnumerator.Current {
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get {
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return current;
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}
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}
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}
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}
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#endif
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