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

   1 #if NET_4_0
   2 // CountdownEvent.cs
   3 //
   4 // Copyright (c) 2008 Jérémie "Garuma" Laval
   5 //
   6 // Permission is hereby granted, free of charge, to any person obtaining a copy
   7 // of this software and associated documentation files (the "Software"), to deal
   8 // in the Software without restriction, including without limitation the rights
   9 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10 // copies of the Software, and to permit persons to whom the Software is
  11 // furnished to do so, subject to the following conditions:
  12 //
  13 // The above copyright notice and this permission notice shall be included in
  14 // all copies or substantial portions of the Software.
  15 //
  16 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22 // THE SOFTWARE.
  23 //
  24 //
  25
  26 using System;
  27
  28 namespace System.Threading
  29 {
  30         public class CountdownEvent : IDisposable
  31         {
  32                 int count;
  33                 readonly int initial;
  34                 ManualResetEvent evt = new ManualResetEvent (false);
  35
  36                 public CountdownEvent (int count)
  37                 {
  38                         if (count < 0)
  39                                 throw new ArgumentOutOfRangeException ("count is negative");
  40                         this.initial = this.count = count;
  41                 }
  42
  43                 public bool Signal ()
  44                 {
  45                         return Signal (1);
  46                 }
  47
  48                 public bool Signal (int num)
  49                 {
  50                         if (num < 0)
  51                                 throw new ArgumentOutOfRangeException ("num");
  52
  53                         Action<int> check = delegate (int value) {
  54                                 if (value < 0)
  55                                 throw new InvalidOperationException ("the specified count is larger that CurrentCount");
  56                         };
  57
  58                         int newValue;
  59                         if (!ApplyOperation (-num, check, out newValue))
  60                                 throw new InvalidOperationException ("The event is already set");
  61
  62                         if (newValue <= 0) {
  63                                 evt.Set ();
  64                                 return true;
  65                         }
  66
  67                         return false;
  68                 }
  69
  70                 public void AddCount ()
  71                 {
  72                         AddCount (1);
  73                 }
  74
  75                 public void AddCount (int num)
  76                 {
  77                         if (num < 0)
  78                                 throw new ArgumentOutOfRangeException ("num");
  79
  80                         if (!TryAddCount (num))
  81                                 throw new InvalidOperationException ("The event is already set");
  82                 }
  83
  84                 public bool TryAddCount ()
  85                 {
  86                         return TryAddCount (1);
  87                 }
  88
  89                 public bool TryAddCount (int num)
  90                 {
  91                         if (num < 0)
  92                                 throw new ArgumentOutOfRangeException ("num");
  93
  94                         Action<int> check = delegate (int value) {      };
  95
  96                         return ApplyOperation (num, check);
  97                 }
  98
  99                 bool ApplyOperation (int num, Action<int> doCheck)
 100                 {
 101                         int temp;
 102                         return ApplyOperation (num, doCheck, out temp);
 103                 }
 104
 105                 bool ApplyOperation (int num, Action<int> doCheck, out int newValue)
 106                 {
 107                         int oldCount;
 108                         newValue = 0;
 109
 110                         do {
 111                                 if (IsSet)
 112                                         return false;
 113
 114                                 oldCount = count;
 115                                 newValue = oldCount + num;
 116
 117                                 doCheck (newValue);
 118
 119                         } while (Interlocked.CompareExchange (ref count, newValue, oldCount) != oldCount);
 120
 121                         return true;
 122                 }
 123
 124                 public void Wait ()
 125                 {
 126                         SpinWait wait = new SpinWait ();
 127                         while (!IsSet) {
 128                                 wait.SpinOnce ();
 129                         }
 130                 }
 131
 132                 public void Wait (CancellationToken token)
 133                 {
 134                         Wait (() => token.IsCancellationRequested);
 135                 }
 136
 137                 public bool Wait (int timeoutMilli)
 138                 {
 139                         if (timeoutMilli == -1) {
 140                                 Wait ();
 141                                 return true;
 142                         }
 143
 144                         Watch sw = Watch.StartNew ();
 145                         long timeout = (long)timeoutMilli;
 146
 147                         bool result = Wait (() => sw.ElapsedMilliseconds > timeout);
 148                         sw.Stop ();
 149
 150                         return result;
 151                 }
 152
 153                 public bool Wait(TimeSpan span)
 154                 {
 155                         return Wait ((int)span.TotalMilliseconds);
 156                 }
 157
 158                 public bool Wait (int timeoutMilli, CancellationToken token)
 159                 {
 160                         if (timeoutMilli == -1) {
 161                                 Wait ();
 162                                 return true;
 163                         }
 164
 165                         Watch sw = Watch.StartNew ();
 166                         long timeout = (long)timeoutMilli;
 167
 168                         bool result = Wait (() => sw.ElapsedMilliseconds > timeout || token.IsCancellationRequested);
 169                         sw.Stop ();
 170
 171                         return result;
 172                 }
 173
 174                 public bool Wait(TimeSpan span, CancellationToken token)
 175                 {
 176                         return Wait ((int)span.TotalMilliseconds, token);
 177                 }
 178
 179                 bool Wait (Func<bool> waitPredicate)
 180                 {
 181                         SpinWait wait = new SpinWait ();
 182
 183                         while (!IsSet) {
 184                                 if (waitPredicate ())
 185                                         return false;
 186                                 wait.SpinOnce ();
 187                         }
 188
 189                         return true;
 190                 }
 191
 192                 public void Reset ()
 193                 {
 194                         Reset (initial);
 195                 }
 196
 197                 public void Reset (int value)
 198                 {
 199                         evt.Reset ();
 200                         Interlocked.Exchange (ref count, value);
 201                 }
 202
 203                 public int CurrentCount {
 204                         get {
 205                                 return count;
 206                         }
 207                 }
 208
 209                 public int InitialCount {
 210                         get {
 211                                 return initial;
 212                         }
 213                 }
 214
 215                 public bool IsSet {
 216                         get {
 217                                 return count <= 0;
 218                         }
 219                 }
 220
 221                 public WaitHandle WaitHandle {
 222                         get {
 223                                 return evt;
 224                         }
 225                 }
 226
 227                 #region IDisposable implementation
 228
 229                 public void Dispose ()
 230                 {
 231
 232                 }
 233
 234                 protected virtual void Dispose (bool managedRes)
 235                 {
 236
 237                 }
 238                 #endregion
 239         }
 240 }
 241 #endif