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/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Parallel / Scheduling / OrderPreservingSpoolingTask.cs / 1305376 / OrderPreservingSpoolingTask.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // OrderPreservingSpoolingTask.cs // //[....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Threading; using System.Threading.Tasks; using System.Diagnostics.Contracts; namespace System.Linq.Parallel { ////// A spooling task handles marshaling data from a producer to a consumer. It's given /// a single enumerator object that contains all of the production algorithms, a single /// destination channel from which consumers draw results, and (optionally) a /// synchronization primitive using which to notify asynchronous consumers. This /// particular task variant preserves sort order in the final data. /// ////// internal class OrderPreservingSpoolingTask : SpoolingTaskBase { private Shared m_results; // The destination array cell into which data is placed. private SortHelper m_sortHelper; // A helper that performs the sorting. //------------------------------------------------------------------------------------ // Creates, but does not execute, a new spooling task. // // Arguments: // taskIndex - the unique index of this task // ordinalIndexState - the state of ordinal indices // source - the producer enumerator // destination - the destination channel into which to spool elements // // Assumptions: // Source cannot be null, although the other arguments may be. // private OrderPreservingSpoolingTask( int taskIndex, QueryTaskGroupState groupState, Shared results, SortHelper sortHelper) : base(taskIndex, groupState) { Contract.Assert(groupState != null); Contract.Assert(results != null); Contract.Assert(sortHelper != null); m_results = results; m_sortHelper = sortHelper; } //----------------------------------------------------------------------------------- // Creates and begins execution of a new spooling task. If pipelineMerges is specified, // we will execute the task asynchronously; otherwise, this is done synchronously, // and by the time this API has returned all of the results have been produced. // // Arguments: // source - the producer enumerator // destination - the destination channel into which to spool elements // ordinalIndexState - state of the index of the input to the merge // // Assumptions: // Source cannot be null, although the other arguments may be. // internal static void Spool( QueryTaskGroupState groupState, PartitionedStream partitions, Shared results, TaskScheduler taskScheduler) { Contract.Assert(groupState != null); Contract.Assert(partitions != null); Contract.Assert(results != null); Contract.Assert(results.Value == null); // Determine how many async tasks to create. int maxToRunInParallel = partitions.PartitionCount - 1; // Generate a set of sort helpers. SortHelper [] sortHelpers = SortHelper .GenerateSortHelpers(partitions, groupState); // Ensure all tasks in this query are parented under a common root. Task rootTask = new Task( () => { // Create tasks that will enumerate the partitions in parallel. We'll use the current // thread for one task and then block before returning to the caller, until all results // have been accumulated. Pipelining is not supported by sort merges. for (int i = 0; i < maxToRunInParallel; i++) { TraceHelpers.TraceInfo("OrderPreservingSpoolingTask::Spool: Running partition[{0}] asynchronously", i); QueryTask asyncTask = new OrderPreservingSpoolingTask ( i, groupState, results, sortHelpers[i]); asyncTask.RunAsynchronously(taskScheduler); } // Run one task synchronously on the current thread. TraceHelpers.TraceInfo("OrderPreservingSpoolingTask::Spool: Running partition[{0}] synchronously", maxToRunInParallel); QueryTask syncTask = new OrderPreservingSpoolingTask ( maxToRunInParallel, groupState, results, sortHelpers[maxToRunInParallel]); syncTask.RunSynchronously(taskScheduler); }); // Begin the query on the calling thread. groupState.QueryBegin(rootTask); // We don't want to return until the task is finished. Run it on the calling thread. rootTask.RunSynchronously(taskScheduler); // Destroy the state associated with our sort helpers. for (int i = 0; i < sortHelpers.Length; i++) { sortHelpers[i].Dispose(); } // End the query, which has the effect of propagating any unhandled exceptions. groupState.QueryEnd(false); } //----------------------------------------------------------------------------------- // This method is responsible for enumerating results and enqueueing them to // the output channel(s) as appropriate. Each base class implements its own. // protected override void SpoolingWork() { Contract.Assert(m_sortHelper != null); // This task must perform a sort just prior to handing data to the merge. // We just defer to a sort helper object for this task. TInputOutput[] sortedOutput = m_sortHelper.Sort(); if (!m_groupState.CancellationState.MergedCancellationToken.IsCancellationRequested) { // The 0th task is responsible for communicating the results to the merging infrastructure. // By this point, the results have been sorted, so we just publish a reference to the array. if (m_taskIndex == 0) { Contract.Assert(sortedOutput != null); m_results.Value = sortedOutput; } } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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