mcs/class/System.Threading.Tasks.Dataflow/System.Threading.Tasks.Dataflow/BatchedJoinBlock.cs

   1 // BatchedJoinBlock.cs
   2 //
   3 // Copyright (c) 2012 Petr Onderka
   4 //
   5 // Permission is hereby granted, free of charge, to any person obtaining a copy
   6 // of this software and associated documentation files (the "Software"), to deal
   7 // in the Software without restriction, including without limitation the rights
   8 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   9 // copies of the Software, and to permit persons to whom the Software is
  10 // furnished to do so, subject to the following conditions:
  11 //
  12 // The above copyright notice and this permission notice shall be included in
  13 // all copies or substantial portions of the Software.
  14 //
  15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  18 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  21 // THE SOFTWARE.
  22 //
  23 //
  24
  25 using System.Collections.Generic;
  26
  27 namespace System.Threading.Tasks.Dataflow {
  28         public sealed class BatchedJoinBlock<T1, T2> :
  29                 IReceivableSourceBlock<Tuple<IList<T1>, IList<T2>>> {
  30                 GroupingDataflowBlockOptions options;
  31
  32                 CompletionHelper completionHelper;
  33                 readonly MessageOutgoingQueue<Tuple<IList<T1>, IList<T2>>> outgoing;
  34                 DataflowMessageHeader headers;
  35                 SpinLock batchLock;
  36
  37                 readonly JoinTarget<T1> target1;
  38                 readonly JoinTarget<T2> target2;
  39
  40                 int batchCount;
  41
  42                 public BatchedJoinBlock (int batchSize)
  43                         : this (batchSize, GroupingDataflowBlockOptions.Default)
  44                 {
  45                 }
  46
  47                 public BatchedJoinBlock (int batchSize,
  48                                          GroupingDataflowBlockOptions dataflowBlockOptions)
  49                 {
  50                         if (batchSize <= 0)
  51                                 throw new ArgumentOutOfRangeException (
  52                                         "batchSize", batchSize, "The batchSize must be positive.");
  53                         if (dataflowBlockOptions == null)
  54                                 throw new ArgumentNullException ("dataflowBlockOptions");
  55
  56                         BatchSize = batchSize;
  57                         options = dataflowBlockOptions;
  58                         completionHelper = CompletionHelper.GetNew (dataflowBlockOptions);
  59
  60                         target1 = new JoinTarget<T1> (
  61                                 this, SignalTarget, completionHelper, () => outgoing.IsCompleted);
  62                         target2 = new JoinTarget<T2> (
  63                                 this, SignalTarget, completionHelper, () => outgoing.IsCompleted);
  64
  65                         outgoing = new MessageOutgoingQueue<Tuple<IList<T1>, IList<T2>>> (
  66                                 this, completionHelper,
  67                                 () => target1.Buffer.IsCompleted || target2.Buffer.IsCompleted, options);
  68                 }
  69
  70                 public int BatchSize { get; private set; }
  71
  72                 public ITargetBlock<T1> Target1 {
  73                         get { return target1; }
  74                 }
  75
  76                 public ITargetBlock<T2> Target2 {
  77                         get { return target2; }
  78                 }
  79
  80                 private void SignalTarget()
  81                 {
  82                         int current = Interlocked.Increment (ref batchCount);
  83
  84                         if (current % BatchSize != 0)
  85                                 return;
  86
  87                         Interlocked.Add (ref batchCount, -current);
  88
  89                         MakeBatch (BatchSize);
  90                 }
  91
  92                 void MakeBatch (int batchSize)
  93                 {
  94                         var list1 = new List<T1> ();
  95                         var list2 = new List<T2> ();
  96
  97                         // lock is necessary here to make sure items are in the correct order
  98                         bool taken = false;
  99                         try {
 100                                 batchLock.Enter (ref taken);
 101
 102                                 int i = 0;
 103
 104                                 T1 item1;
 105                                 while (i < batchSize && target1.Buffer.TryTake (out item1)) {
 106                                         list1.Add (item1);
 107                                         i++;
 108                                 }
 109
 110                                 T2 item2;
 111                                 while (i < batchSize && target2.Buffer.TryTake (out item2)) {
 112                                         list2.Add (item2);
 113                                         i++;
 114                                 }
 115
 116                                 if (i < batchSize)
 117                                         throw new InvalidOperationException("Unexpected count of items.");
 118                         } finally {
 119                                 if (taken)
 120                                         batchLock.Exit ();
 121                         }
 122
 123                         var batch = Tuple.Create<IList<T1>, IList<T2>> (list1, list2);
 124
 125                         outgoing.AddData (batch);
 126                 }
 127
 128                 public Task Completion {
 129                         get { return completionHelper.Completion; }
 130                 }
 131
 132                 public void Complete ()
 133                 {
 134                         outgoing.Complete ();
 135                 }
 136
 137                 void IDataflowBlock.Fault (Exception exception)
 138                 {
 139                         completionHelper.RequestFault (exception);
 140                 }
 141
 142                 Tuple<IList<T1>, IList<T2>> ISourceBlock<Tuple<IList<T1>, IList<T2>>>.ConsumeMessage (
 143                         DataflowMessageHeader messageHeader,
 144                         ITargetBlock<Tuple<IList<T1>, IList<T2>>> target,
 145                         out bool messageConsumed)
 146                 {
 147                         return outgoing.ConsumeMessage (messageHeader, target, out messageConsumed);
 148                 }
 149
 150                 public IDisposable LinkTo (ITargetBlock<Tuple<IList<T1>, IList<T2>>> target,
 151                                            DataflowLinkOptions linkOptions)
 152                 {
 153                         return outgoing.AddTarget(target, linkOptions);
 154                 }
 155
 156                 void ISourceBlock<Tuple<IList<T1>, IList<T2>>>.ReleaseReservation (
 157                         DataflowMessageHeader messageHeader,
 158                         ITargetBlock<Tuple<IList<T1>, IList<T2>>> target)
 159                 {
 160                         outgoing.ReleaseReservation (messageHeader, target);
 161                 }
 162
 163                 bool ISourceBlock<Tuple<IList<T1>, IList<T2>>>.ReserveMessage (
 164                         DataflowMessageHeader messageHeader,
 165                         ITargetBlock<Tuple<IList<T1>, IList<T2>>> target)
 166                 {
 167                         return outgoing.ReserveMessage (messageHeader, target);
 168                 }
 169
 170                 public bool TryReceive (Predicate<Tuple<IList<T1>, IList<T2>>> filter,
 171                                         out Tuple<IList<T1>, IList<T2>> item)
 172                 {
 173                         return outgoing.TryReceive (filter, out item);
 174                 }
 175
 176                 public bool TryReceiveAll (out IList<Tuple<IList<T1>, IList<T2>>> items)
 177                 {
 178                         return outgoing.TryReceiveAll (out items);
 179                 }
 180
 181                 public override string ToString ()
 182                 {
 183                         return NameHelper.GetName (this, options);
 184                 }
 185         }
 186 }