mcs/class/System.Core/System.Linq.Parallel/ParallelExecuter.cs

   1 //
   2 // ParallelExecuter.cs
   3 //
   4 // Author:
   5 //       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
   6 //
   7 // Copyright (c) 2010 Jérémie "Garuma" Laval
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining a copy
  10 // of this software and associated documentation files (the "Software"), to deal
  11 // in the Software without restriction, including without limitation the rights
  12 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13 // copies of the Software, and to permit persons to whom the Software is
  14 // furnished to do so, subject to the following conditions:
  15 //
  16 // The above copyright notice and this permission notice shall be included in
  17 // all copies or substantial portions of the Software.
  18 //
  19 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  22 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25 // THE SOFTWARE.
  26
  27 #if NET_4_0
  28 using System;
  29 using System.Threading;
  30 using System.Threading.Tasks;
  31 using System.Collections;
  32 using System.Collections.Generic;
  33 using System.Collections.Concurrent;
  34
  35 namespace System.Linq
  36 {
  37         internal static class ParallelExecuter
  38         {
  39                 internal static QueryOptions CheckQuery<T> (QueryBaseNode<T> startingNode)
  40                 {
  41                         return CheckQuery<T> (startingNode, false);
  42                 }
  43
  44                 internal static QueryOptions CheckQuery<T> (QueryBaseNode<T> startingNode, bool blocking)
  45                 {
  46                         return CheckQuery (startingNode, GetBestWorkerNumber (blocking));
  47                 }
  48
  49                 internal static QueryOptions CheckQuery<T> (QueryBaseNode<T> startingNode, int partitionCount)
  50                 {
  51                         QueryCheckerVisitor visitor = new QueryCheckerVisitor (partitionCount);
  52                         startingNode.Visit (visitor);
  53
  54                         return visitor.Options;
  55                 }
  56
  57                 internal static CancellationToken Chain (this CancellationToken self, CancellationTokenSource other)
  58                 {
  59                         CancellationTokenSource linked = CancellationTokenSource.CreateLinkedTokenSource (self, other.Token);
  60                         return linked.Token;
  61                 }
  62
  63                 // TODO: replace the CheckQuery call with a custom visitor that stops after the
  64                 // first encountered order guard
  65                 internal static bool IsOrdered<TSource> (this QueryBaseNode<TSource> source)
  66                 {
  67                         return CheckQuery (source).BehindOrderGuard.Value;
  68                 }
  69
  70                 internal static int GetBestWorkerNumber ()
  71                 {
  72                         return GetBestWorkerNumber (false);
  73                 }
  74
  75                 internal static int GetBestWorkerNumber (bool blocking)
  76                 {
  77                         return blocking ? Environment.ProcessorCount + 1 : Environment.ProcessorCount;
  78                 }
  79
  80                 internal static Task[] Process<TSource, TElement> (QueryBaseNode<TSource> node, Action<TElement> call,
  81                                                                    Func<QueryBaseNode<TSource>, QueryOptions, IList<IEnumerable<TElement>>> acquisitionFunc,
  82                                                                    QueryOptions options)
  83                 {
  84                         return Process<TSource, TElement> (node, call, acquisitionFunc, null, options);
  85                 }
  86
  87                 internal static Task[] Process<TSource, TElement> (QueryBaseNode<TSource> node, Action<TElement> call,
  88                                                                    Func<QueryBaseNode<TSource>, QueryOptions, IList<IEnumerable<TElement>>> acquisitionFunc,
  89                                                                    Action endAction,
  90                                                                    QueryOptions options)
  91                 {
  92                         return Process<TSource, TElement> (node,
  93                                                            (e, i) => call (e),
  94                                                            acquisitionFunc,
  95                                                            endAction == null ? ((Action<int>)null) : (i) => endAction (),
  96                                                            options);
  97                 }
  98
  99                 internal static Task[] Process<TSource, TElement> (QueryBaseNode<TSource> node, Action<TElement, int> call,
 100                                                                    Func<QueryBaseNode<TSource>, QueryOptions, IList<IEnumerable<TElement>>> acquisitionFunc,
 101                                                                    Action<int> endAction,
 102                                                                    QueryOptions options)
 103                 {
 104                         IList<IEnumerable<TElement>> enumerables = acquisitionFunc (node, options);
 105
 106                         Task[] tasks = new Task[enumerables.Count];
 107
 108                         for (int i = 0; i < tasks.Length; i++) {
 109                                 int index = i;
 110                                 tasks[i] = Task.Factory.StartNew (() => {
 111                                         foreach (TElement item in enumerables[index]) {
 112                                                 // This is from specific operators
 113                                                 if (options.ImplementerToken.IsCancellationRequested)
 114                                                         break;
 115                                                 if (options.Token.IsCancellationRequested)
 116                                                         throw new OperationCanceledException (options.Token);
 117
 118                                                 call (item, index);
 119                                         }
 120                                         if (endAction != null)
 121                                                 endAction (index);
 122                                   }, options.Token);
 123                         }
 124
 125                         return tasks;
 126                 }
 127
 128                 internal static void ProcessAndBlock<T> (QueryBaseNode<T> node, Action<T> call)
 129                 {
 130                         QueryOptions options = CheckQuery (node, true);
 131
 132                         Task[] tasks = Process (node, call, (n, o) => n.GetEnumerables (o), options);
 133                         Task.WaitAll (tasks, options.Token);
 134                 }
 135
 136                 internal static Action ProcessAndCallback<T> (QueryBaseNode<T> node, Action<T> call,
 137                                                               Action callback, QueryOptions options)
 138                 {
 139                         Task[] tasks = Process (node, call, (n, o) => n.GetEnumerables (o), options);
 140                         if (callback != null)
 141                                 Task.Factory.ContinueWhenAll (tasks,  (_) => callback ());
 142
 143                         return () => Task.WaitAll (tasks, options.Token);
 144                 }
 145
 146                 internal static Action ProcessAndCallback<T> (QueryBaseNode<T> node, Action<KeyValuePair<long, T>, int> call,
 147                                                               Action<int> endAction,
 148                                                               Action callback, QueryOptions options)
 149                 {
 150                         Task[] tasks = Process (node, call, (n, o) => n.GetOrderedEnumerables (o), endAction, options);
 151                         if (callback != null)
 152                                 Task.Factory.ContinueWhenAll (tasks,  (_) => callback ());
 153
 154                         return () => Task.WaitAll (tasks, options.Token);
 155                 }
 156
 157                 internal static void ProcessAndAggregate<T, U> (QueryBaseNode<T> node,
 158                                                                 Func<U> seedFunc,
 159                                                                 Func<U, T, U> localCall,
 160                                                                 Action<IList<U>> call)
 161                 {
 162                         QueryOptions options = CheckQuery (node, true);
 163
 164                         IList<IEnumerable<T>> enumerables = node.GetEnumerables (options);
 165                         U[] locals = new U[enumerables.Count];
 166                         Task[] tasks = new Task[enumerables.Count];
 167
 168                         if (seedFunc != null) {
 169                                 for (int i = 0; i < locals.Length; i++)
 170                                         locals[i] = seedFunc ();
 171                         }
 172
 173                         for (int i = 0; i < tasks.Length; i++) {
 174                                 int index = i;
 175                                 bool firstRun = true;
 176
 177                                 tasks[i] = Task.Factory.StartNew (() => {
 178                                         foreach (T item in enumerables[index]) {
 179                                                 // This is from specific operators
 180                                                 if (options.ImplementerToken.IsCancellationRequested)
 181                                                         break;
 182                                                 if (options.Token.IsCancellationRequested)
 183                                                         throw new OperationCanceledException (options.Token);
 184
 185                                                 if (firstRun && seedFunc == null) {
 186                                                         firstRun = false;
 187                                                         // HACK: TODO: omgwtfitsuckssomuch
 188                                                         locals[index] = (U)(object)item;
 189                                                         continue;
 190                                                 }
 191
 192                                                 U acc = locals[index];
 193                                                 locals[index] = localCall (acc, item);
 194                                         }
 195                                 }, options.Token);
 196                         }
 197
 198                         Task.WaitAll (tasks, options.Token);
 199
 200                         if (call != null)
 201                                 call (locals);
 202                 }
 203         }
 204 }
 205 #endif