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