class/System/System.Threading/Barrier.cs

   1 #if NET_4_0
   2 //
   3 // Barrier.cs
   4 //
   5 // Author:
   6 //       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
   7 //
   8 // Copyright (c) 2009 Jérémie "Garuma" Laval
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining a copy
  11 // of this software and associated documentation files (the "Software"), to deal
  12 // in the Software without restriction, including without limitation the rights
  13 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14 // copies of the Software, and to permit persons to whom the Software is
  15 // furnished to do so, subject to the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be included in
  18 // all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  26 // THE SOFTWARE.
  27
  28 using System;
  29
  30 namespace System.Threading
  31 {
  32         public class Barrier : IDisposable
  33         {
  34                 const int MAX_PARTICIPANTS = 32767;
  35                 Action<Barrier> postPhaseAction;
  36
  37                 int participants;
  38                 CountdownEvent cntd;
  39                 AtomicBoolean cleaned = new AtomicBoolean ();
  40                 long phase;
  41
  42                 public Barrier (int participants) : this (participants, null)
  43                 {
  44                 }
  45
  46                 public Barrier (int participants, Action<Barrier> postPhaseAction)
  47                 {
  48                         if (participants < 0 || participants > MAX_PARTICIPANTS)
  49                                 throw new ArgumentOutOfRangeException ("participants");
  50
  51                         this.participants = participants;
  52                         this.postPhaseAction = postPhaseAction;
  53
  54                         InitCountdownEvent ();
  55                 }
  56
  57                 public void Dispose ()
  58                 {
  59                         Dispose (true);
  60                 }
  61
  62                 protected virtual void Dispose (bool disposing)
  63                 {
  64                         if (disposing){
  65                                 if (cntd != null){
  66                                         cntd.Dispose ();
  67                                         cntd = null;
  68                                 }
  69                                 cleaned = null;
  70                                 postPhaseAction = null;
  71                         }
  72                 }
  73
  74                 void InitCountdownEvent ()
  75                 {
  76                         cleaned = new AtomicBoolean ();
  77                         cntd = new CountdownEvent (participants);
  78                 }
  79
  80                 public long AddParticipant ()
  81                 {
  82                         return AddParticipants (1);
  83                 }
  84
  85                 static Exception GetDisposed ()
  86                 {
  87                         return new ObjectDisposedException ("Barrier");
  88                 }
  89
  90                 public long AddParticipants (int participantCount)
  91                 {
  92                         if (cleaned == null)
  93                                 throw GetDisposed ();
  94
  95                         if (participantCount < 0)
  96                                 throw new InvalidOperationException ();
  97
  98                         // Basically, we try to add ourselves and return
  99                         // the phase. If the call return false, we repeatdly try
 100                         // to add ourselves for the next phase
 101                         do {
 102                                 if (cntd.TryAddCount (participantCount)) {
 103                                         Interlocked.Add (ref participants, participantCount);
 104                                         return phase;
 105                                 }
 106                         } while (true);
 107                 }
 108
 109                 public void RemoveParticipant ()
 110                 {
 111                         RemoveParticipants (1);
 112                 }
 113
 114                 public void RemoveParticipants (int participantCount)
 115                 {
 116                         if (cleaned == null)
 117                                 throw GetDisposed ();
 118                         if (participantCount < 0)
 119                                 throw new ArgumentOutOfRangeException ("participantCount");
 120
 121                         if (cntd.Signal (participantCount))
 122                                 PostPhaseAction (cleaned);
 123                         Interlocked.Add (ref participants, -participantCount);
 124                 }
 125
 126                 public void SignalAndWait ()
 127                 {
 128                         if (cleaned == null)
 129                                 throw GetDisposed ();
 130                         SignalAndWait ((c) => { c.Wait (); return true; });
 131                 }
 132
 133                 public bool SignalAndWait (int millisecondTimeout)
 134                 {
 135                         if (cleaned == null)
 136                                 throw GetDisposed ();
 137                         return SignalAndWait ((c) => c.Wait (millisecondTimeout));
 138                 }
 139
 140                 public bool SignalAndWait (TimeSpan ts)
 141                 {
 142                         if (cleaned == null)
 143                                 throw GetDisposed ();
 144                         return SignalAndWait ((c) => c.Wait (ts));
 145                 }
 146
 147                 public bool SignalAndWait (int millisecondTimeout, CancellationToken token)
 148                 {
 149                         if (cleaned == null)
 150                                 throw GetDisposed ();
 151                         return SignalAndWait ((c) => c.Wait (millisecondTimeout, token));
 152                 }
 153
 154                 public bool SignalAndWait (TimeSpan ts, CancellationToken token)
 155                 {
 156                         if (cleaned == null)
 157                                 throw GetDisposed ();
 158                         return SignalAndWait ((c) => c.Wait (ts, token));
 159                 }
 160
 161                 bool SignalAndWait (Func<CountdownEvent, bool> associate)
 162                 {
 163                         bool result;
 164                         AtomicBoolean cl = cleaned;
 165                         CountdownEvent temp = cntd;
 166
 167                         if (!temp.Signal ()) {
 168                                 result = Wait (associate, temp, cl);
 169                         } else {
 170                                 result = true;
 171                                 PostPhaseAction (cl);
 172                         }
 173
 174                         return result;
 175                 }
 176
 177                 bool Wait (Func<CountdownEvent, bool> associate, CountdownEvent temp, AtomicBoolean cl)
 178                 {
 179                         if (!associate (temp))
 180                                 return false;
 181
 182                         SpinWait sw = new SpinWait ();
 183                         while (!cl.Value)
 184                                 sw.SpinOnce ();
 185
 186                         return true;
 187                 }
 188
 189                 void PostPhaseAction (AtomicBoolean cl)
 190                 {
 191                         if (postPhaseAction != null)
 192                                 postPhaseAction (this);
 193
 194                         InitCountdownEvent ();
 195
 196                         cl.Value = true;
 197                         phase++;
 198                 }
 199
 200                 public long CurrentPhaseNumber {
 201                         get {
 202                                 return phase;
 203                         }
 204                 }
 205
 206                 public int ParticipantCount  {
 207                         get {
 208                                 return participants;
 209                         }
 210                 }
 211         }
 212 }
 213 #endif