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

   1 // BufferBlock.cs
   2 //
   3 // Copyright (c) 2011 Jérémie "garuma" Laval
   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
  26 using System;
  27 using System.Threading.Tasks;
  28 using System.Collections.Generic;
  29 using System.Collections.Concurrent;
  30
  31 namespace System.Threading.Tasks.Dataflow
  32 {
  33         public sealed class BufferBlock<T> : IPropagatorBlock<T, T>, ITargetBlock<T>, IDataflowBlock, ISourceBlock<T>, IReceivableSourceBlock<T>
  34         {
  35                 static readonly DataflowBlockOptions defaultOptions = new DataflowBlockOptions ();
  36
  37                 DataflowBlockOptions dataflowBlockOptions;
  38                 CompletionHelper compHelper = CompletionHelper.GetNew ();
  39                 MessageBox<T> messageBox;
  40                 MessageVault<T> vault;
  41                 MessageOutgoingQueue<T> outgoing;
  42                 BlockingCollection<T> messageQueue = new BlockingCollection<T> ();
  43                 TargetBuffer<T> targets = new TargetBuffer<T> ();
  44                 DataflowMessageHeader headers = DataflowMessageHeader.NewValid ();
  45
  46                 public BufferBlock () : this (defaultOptions)
  47                 {
  48
  49                 }
  50
  51                 public BufferBlock (DataflowBlockOptions dataflowBlockOptions)
  52                 {
  53                         if (dataflowBlockOptions == null)
  54                                 throw new ArgumentNullException ("dataflowBlockOptions");
  55
  56                         this.dataflowBlockOptions = dataflowBlockOptions;
  57                         this.messageBox = new PassingMessageBox<T> (messageQueue, compHelper, () => outgoing.IsCompleted, ProcessQueue, dataflowBlockOptions);
  58                         this.outgoing = new MessageOutgoingQueue<T> (compHelper, () => messageQueue.IsCompleted);
  59                         this.vault = new MessageVault<T> ();
  60                 }
  61
  62                 public DataflowMessageStatus OfferMessage (DataflowMessageHeader messageHeader,
  63                                                            T messageValue,
  64                                                            ISourceBlock<T> source,
  65                                                            bool consumeToAccept)
  66                 {
  67                         return messageBox.OfferMessage (this, messageHeader, messageValue, source, consumeToAccept);
  68                 }
  69
  70                 public IDisposable LinkTo (ITargetBlock<T> target, bool unlinkAfterOne)
  71                 {
  72                         var result = targets.AddTarget (target, unlinkAfterOne);
  73                         ProcessQueue ();
  74
  75                         return result;
  76                 }
  77
  78                 public T ConsumeMessage (DataflowMessageHeader messageHeader, ITargetBlock<T> target, out bool messageConsumed)
  79                 {
  80                         return vault.ConsumeMessage (messageHeader, target, out messageConsumed);
  81                 }
  82
  83                 public void ReleaseReservation (DataflowMessageHeader messageHeader, ITargetBlock<T> target)
  84                 {
  85                         vault.ReleaseReservation (messageHeader, target);
  86                 }
  87
  88                 public bool ReserveMessage (DataflowMessageHeader messageHeader, ITargetBlock<T> target)
  89                 {
  90                         return vault.ReserveMessage (messageHeader, target);
  91                 }
  92
  93                 public bool TryReceive (Predicate<T> filter, out T item)
  94                 {
  95                         return outgoing.TryReceive (filter, out item);
  96                 }
  97
  98                 public bool TryReceiveAll (out IList<T> items)
  99                 {
 100                         return outgoing.TryReceiveAll (out items);
 101                 }
 102
 103                 void ProcessQueue ()
 104                 {
 105                         ITargetBlock<T> target;
 106                         T input;
 107
 108                         while (messageQueue.TryTake (out input)) {
 109                                 if ((target = targets.Current) != null)
 110                                         target.OfferMessage (headers.Increment (), input, this, false);
 111                                 else
 112                                         outgoing.AddData (input);
 113                         }
 114
 115                         if (!outgoing.IsEmpty && (target = targets.Current) != null)
 116                                 outgoing.ProcessForTarget (target, this, false, ref headers);
 117                 }
 118
 119                 public void Complete ()
 120                 {
 121                         messageBox.Complete ();
 122                         outgoing.Complete ();
 123                 }
 124
 125                 public void Fault (Exception ex)
 126                 {
 127                         compHelper.Fault (ex);
 128                 }
 129
 130                 public Task Completion {
 131                         get {
 132                                 return compHelper.Completion;
 133                         }
 134                 }
 135
 136                 public int Count {
 137                         get {
 138                                 return outgoing.Count;
 139                         }
 140                 }
 141
 142                 public override string ToString ()
 143                 {
 144                         return NameHelper.GetName (this, dataflowBlockOptions);
 145                 }
 146         }
 147 }
 148