mcs/class/corlib/System.Threading/CountdownEvent.cs

   1 // CountdownEvent.cs
   2 //
   3 // Authors:
   4 //    Marek Safar  <marek.safar@gmail.com>
   5 //
   6 // Copyright (c) 2008 Jérémie "Garuma" Laval
   7 // Copyright 2011 Xamarin Inc (http://www.xamarin.com).
   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 //
  28
  29 #if NET_4_0
  30
  31 namespace System.Threading
  32 {
  33         [System.Diagnostics.DebuggerDisplayAttribute ("Initial Count={InitialCount}, Current Count={CurrentCount}")]
  34         public class CountdownEvent : IDisposable
  35         {
  36                 int initialCount;
  37                 int initial;
  38                 ManualResetEventSlim evt;
  39
  40                 public CountdownEvent (int initialCount)
  41                 {
  42                         if (initialCount < 0)
  43                                 throw new ArgumentOutOfRangeException ("initialCount");
  44
  45                         evt = new ManualResetEventSlim (initialCount == 0);
  46                         this.initial = this.initialCount = initialCount;
  47                 }
  48
  49                 public int CurrentCount {
  50                         get {
  51                                 return initialCount;
  52                         }
  53                 }
  54
  55                 public int InitialCount {
  56                         get {
  57                                 return initial;
  58                         }
  59                 }
  60
  61                 public bool IsSet {
  62                         get {
  63                                 return initialCount == 0;
  64                         }
  65                 }
  66
  67                 public WaitHandle WaitHandle {
  68                         get {
  69                                 return evt.WaitHandle;
  70                         }
  71                 }
  72
  73                 public bool Signal ()
  74                 {
  75                         return Signal (1);
  76                 }
  77
  78                 public bool Signal (int signalCount)
  79                 {
  80                         if (signalCount <= 0)
  81                                 throw new ArgumentOutOfRangeException ("signalCount");
  82
  83                         CheckDisposed ();
  84
  85                         int newValue;
  86                         if (!ApplyOperation (-signalCount, out newValue))
  87                                 throw new InvalidOperationException ("The event is already set");
  88
  89                         if (newValue == 0) {
  90                                 evt.Set ();
  91                                 return true;
  92                         }
  93
  94                         return false;
  95                 }
  96
  97                 public void AddCount ()
  98                 {
  99                         AddCount (1);
 100                 }
 101
 102                 public void AddCount (int signalCount)
 103                 {
 104                         if (!TryAddCount (signalCount))
 105                                 throw new InvalidOperationException ("The event is already signaled and cannot be incremented");
 106                 }
 107
 108                 public bool TryAddCount ()
 109                 {
 110                         return TryAddCount (1);
 111                 }
 112
 113                 public bool TryAddCount (int signalCount)
 114                 {
 115                         if (signalCount <= 0)
 116                                 throw new ArgumentOutOfRangeException ("signalCount");
 117
 118                         CheckDisposed ();
 119
 120                         int temp;
 121                         return ApplyOperation (signalCount, out temp);
 122                 }
 123
 124                 bool ApplyOperation (int num, out int newValue)
 125                 {
 126                         int oldCount;
 127
 128                         do {
 129                                 oldCount = initialCount;
 130                                 if (oldCount == 0) {
 131                                         newValue = 0;
 132                                         return false;
 133                                 }
 134
 135                                 newValue = oldCount + num;
 136
 137                                 if (newValue < 0)
 138                                         return false;
 139                         } while (Interlocked.CompareExchange (ref initialCount, newValue, oldCount) != oldCount);
 140
 141                         return true;
 142                 }
 143
 144                 public void Wait ()
 145                 {
 146                         evt.Wait ();
 147                 }
 148
 149                 public void Wait (CancellationToken cancellationToken)
 150                 {
 151                         evt.Wait (cancellationToken);
 152                 }
 153
 154                 public bool Wait (int millisecondsTimeout)
 155                 {
 156                         return evt.Wait (millisecondsTimeout);
 157                 }
 158
 159                 public bool Wait(TimeSpan timeout)
 160                 {
 161                         return evt.Wait (timeout);
 162                 }
 163
 164                 public bool Wait (int millisecondsTimeout, CancellationToken cancellationToken)
 165                 {
 166                         return evt.Wait (millisecondsTimeout, cancellationToken);
 167                 }
 168
 169                 public bool Wait(TimeSpan timeout, CancellationToken cancellationToken)
 170                 {
 171                         return evt.Wait (timeout, cancellationToken);
 172                 }
 173
 174                 public void Reset ()
 175                 {
 176                         Reset (initial);
 177                 }
 178
 179                 public void Reset (int count)
 180                 {
 181                         if (count < 0)
 182                                 throw new ArgumentOutOfRangeException ("count");
 183
 184                         CheckDisposed ();
 185
 186                         initialCount = initial = count;
 187                         if (count == 0)
 188                                 evt.Set ();
 189                         else
 190                                 evt.Reset ();
 191                 }
 192
 193                 public void Dispose ()
 194                 {
 195                         Dispose (true);
 196                 }
 197
 198                 protected virtual void Dispose (bool disposing)
 199                 {
 200                         if (disposing)
 201                                 evt.Dispose ();
 202                 }
 203
 204                 void CheckDisposed ()
 205                 {
 206                         if (evt.disposed.Value)
 207                                 throw new ObjectDisposedException ("CountdownEvent");
 208                 }
 209         }
 210 }
 211 #endif