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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
//
// BinaryQueryOperator.cs
//
// =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
using System.Collections.Generic;
using System.Diagnostics;
namespace System.Linq.Parallel
{
/// <summary>
/// The base class from which all binary query operators derive, that is, those that
/// have two child operators. This introduces some convenience methods for those
/// classes, as well as any state common to all subclasses.
/// </summary>
/// <typeparam name="TLeftInput"></typeparam>
/// <typeparam name="TRightInput"></typeparam>
/// <typeparam name="TOutput"></typeparam>
internal abstract class BinaryQueryOperator<TLeftInput, TRightInput, TOutput> : QueryOperator<TOutput>
{
// A set of child operators for the current node.
private readonly QueryOperator<TLeftInput> _leftChild;
private readonly QueryOperator<TRightInput> _rightChild;
private OrdinalIndexState _indexState = OrdinalIndexState.Shuffled;
//---------------------------------------------------------------------------------------
// Stores a set of child operators on this query node.
//
internal BinaryQueryOperator(ParallelQuery<TLeftInput> leftChild, ParallelQuery<TRightInput> rightChild)
: this(QueryOperator<TLeftInput>.AsQueryOperator(leftChild), QueryOperator<TRightInput>.AsQueryOperator(rightChild))
{
}
internal BinaryQueryOperator(QueryOperator<TLeftInput> leftChild, QueryOperator<TRightInput> rightChild)
: base(false, leftChild.SpecifiedQuerySettings.Merge(rightChild.SpecifiedQuerySettings))
{
Debug.Assert(leftChild != null && rightChild != null);
_leftChild = leftChild;
_rightChild = rightChild;
}
internal QueryOperator<TLeftInput> LeftChild
{
get { return _leftChild; }
}
internal QueryOperator<TRightInput> RightChild
{
get { return _rightChild; }
}
internal sealed override OrdinalIndexState OrdinalIndexState
{
get { return _indexState; }
}
protected void SetOrdinalIndex(OrdinalIndexState indexState)
{
_indexState = indexState;
}
//---------------------------------------------------------------------------------------
// This method wraps accepts two child partitioned streams, and constructs an output
// partitioned stream. However, instead of returning the transformed partitioned
// stream, we pass it to a recipient object by calling recipient.Give<TNewKey>(..). That
// way, we can "return" a partitioned stream that uses an order key selected by the operator.
//
public abstract void WrapPartitionedStream<TLeftKey, TRightKey>(
PartitionedStream<TLeftInput, TLeftKey> leftPartitionedStream, PartitionedStream<TRightInput, TRightKey> rightPartitionedStream,
IPartitionedStreamRecipient<TOutput> outputRecipient, bool preferStriping, QuerySettings settings);
//---------------------------------------------------------------------------------------
// Implementation of QueryResults for a binary operator. The results will not be indexable
// unless a derived class provides that functionality.
//
internal class BinaryQueryOperatorResults : QueryResults<TOutput>
{
protected QueryResults<TLeftInput> _leftChildQueryResults; // Results of the left child query
protected QueryResults<TRightInput> _rightChildQueryResults; // Results of the right child query
private readonly BinaryQueryOperator<TLeftInput, TRightInput, TOutput> _op; // Operator that generated these results
private QuerySettings _settings; // Settings collected from the query
private readonly bool _preferStriping; // If the results are indexable, should we use striping when partitioning them
internal BinaryQueryOperatorResults(
QueryResults<TLeftInput> leftChildQueryResults, QueryResults<TRightInput> rightChildQueryResults,
BinaryQueryOperator<TLeftInput, TRightInput, TOutput> op, QuerySettings settings,
bool preferStriping)
{
_leftChildQueryResults = leftChildQueryResults;
_rightChildQueryResults = rightChildQueryResults;
_op = op;
_settings = settings;
_preferStriping = preferStriping;
}
internal override void GivePartitionedStream(IPartitionedStreamRecipient<TOutput> recipient)
{
Debug.Assert(IsIndexible == (_op.OrdinalIndexState == OrdinalIndexState.Indexable));
Debug.Assert(_settings.ExecutionMode != null);
if (_settings.ExecutionMode.Value == ParallelExecutionMode.Default && _op.LimitsParallelism)
{
Debug.Assert(_settings.DegreeOfParallelism != null);
// We need to run the query sequentially up to and including this operator
IEnumerable<TOutput> opSequential = _op.AsSequentialQuery(_settings.CancellationState.ExternalCancellationToken);
PartitionedStream<TOutput, int> result = ExchangeUtilities.PartitionDataSource(
opSequential, _settings.DegreeOfParallelism.Value, _preferStriping);
recipient.Receive<int>(result);
}
else if (IsIndexible)
{
Debug.Assert(_settings.DegreeOfParallelism != null);
// The output of this operator is indexable. Pass the partitioned output into the IPartitionedStreamRecipient.
PartitionedStream<TOutput, int> result = ExchangeUtilities.PartitionDataSource(this, _settings.DegreeOfParallelism.Value, _preferStriping);
recipient.Receive<int>(result);
}
else
{
// The common case: get partitions from the child and wrap each partition.
_leftChildQueryResults.GivePartitionedStream(new LeftChildResultsRecipient(recipient, this, _preferStriping, _settings));
}
}
//---------------------------------------------------------------------------------------
// LeftChildResultsRecipient is a recipient of a partitioned stream. It receives a partitioned
// stream from the left child operator, and passes the results along to a
// RightChildResultsRecipient.
//
private sealed class LeftChildResultsRecipient : IPartitionedStreamRecipient<TLeftInput>
{
private readonly IPartitionedStreamRecipient<TOutput> _outputRecipient;
private readonly BinaryQueryOperatorResults _results;
private readonly bool _preferStriping;
private QuerySettings _settings;
internal LeftChildResultsRecipient(IPartitionedStreamRecipient<TOutput> outputRecipient, BinaryQueryOperatorResults results,
bool preferStriping, QuerySettings settings)
{
_outputRecipient = outputRecipient;
_results = results;
_preferStriping = preferStriping;
_settings = settings;
}
public void Receive<TLeftKey>(PartitionedStream<TLeftInput, TLeftKey> source)
{
RightChildResultsRecipient<TLeftKey> rightChildRecipient =
new RightChildResultsRecipient<TLeftKey>(_outputRecipient, _results._op, source, _preferStriping, _settings);
_results._rightChildQueryResults.GivePartitionedStream(rightChildRecipient);
}
}
//---------------------------------------------------------------------------------------
// RightChildResultsRecipient receives a partitioned from the right child operator. Also,
// the partitioned stream from the left child operator is passed into the constructor.
// So, Receive has partitioned streams for both child operators, and also is called in
// a context where it has access to both TLeftKey and TRightKey. Then, it passes both
// streams (as arguments) and key types (as type arguments) to the operator's
// WrapPartitionedStream method.
//
private sealed class RightChildResultsRecipient<TLeftKey> : IPartitionedStreamRecipient<TRightInput>
{
private readonly IPartitionedStreamRecipient<TOutput> _outputRecipient;
private readonly PartitionedStream<TLeftInput, TLeftKey> _leftPartitionedStream;
private readonly BinaryQueryOperator<TLeftInput, TRightInput, TOutput> _op;
private readonly bool _preferStriping;
private QuerySettings _settings;
internal RightChildResultsRecipient(
IPartitionedStreamRecipient<TOutput> outputRecipient, BinaryQueryOperator<TLeftInput, TRightInput, TOutput> op,
PartitionedStream<TLeftInput, TLeftKey> leftPartitionedStream, bool preferStriping, QuerySettings settings)
{
_outputRecipient = outputRecipient;
_op = op;
_preferStriping = preferStriping;
_leftPartitionedStream = leftPartitionedStream;
_settings = settings;
}
public void Receive<TRightKey>(PartitionedStream<TRightInput, TRightKey> rightPartitionedStream)
{
_op.WrapPartitionedStream(_leftPartitionedStream, rightPartitionedStream, _outputRecipient, _preferStriping, _settings);
}
}
}
}
}
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