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

   1 // ManuelResetEventSlim.cs
   2 //
   3 // Copyright (c) 2008 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 #if NET_4_0 || MOBILE
  26
  27 using System;
  28
  29 namespace System.Threading
  30 {
  31         [System.Diagnostics.DebuggerDisplayAttribute ("Set = {IsSet}")]
  32         public class ManualResetEventSlim : IDisposable
  33         {
  34                 const int isSet    = 1;
  35                 const int isNotSet = 0;
  36                 const int defaultSpinCount = 100;
  37
  38                 int state;
  39                 readonly int spinCount;
  40
  41                 ManualResetEvent handle;
  42                 AtomicBooleanValue disposed;
  43                 bool used;
  44
  45                 readonly static Watch sw = Watch.StartNew ();
  46
  47                 public ManualResetEventSlim () : this (false, defaultSpinCount)
  48                 {
  49                 }
  50
  51                 public ManualResetEventSlim (bool initialState) : this (initialState, defaultSpinCount)
  52                 {
  53                 }
  54
  55                 public ManualResetEventSlim (bool initialState, int spinCount)
  56                 {
  57                         if (spinCount < 0)
  58                                 throw new ArgumentOutOfRangeException ("spinCount is less than 0", "spinCount");
  59
  60                         this.state = initialState ? isSet : isNotSet;
  61                         this.spinCount = spinCount;
  62                 }
  63
  64                 public bool IsSet {
  65                         get {
  66                                 return state == isSet;
  67                         }
  68                 }
  69
  70                 public int SpinCount {
  71                         get {
  72                                 return spinCount;
  73                         }
  74                 }
  75
  76                 public void Reset ()
  77                 {
  78                         state = isNotSet;
  79                         if (handle != null) {
  80                                 used = true;
  81                                 Thread.MemoryBarrier ();
  82                                 var tmpHandle = handle;
  83                                 if (tmpHandle != null)
  84                                         tmpHandle.Reset ();
  85                                 Thread.MemoryBarrier ();
  86                                 used = false;
  87                         }
  88                 }
  89
  90                 public void Set ()
  91                 {
  92                         state = isSet;
  93                         if (handle != null) {
  94                                 used = true;
  95                                 Thread.MemoryBarrier ();
  96                                 var tmpHandle = handle;
  97                                 if (tmpHandle != null)
  98                                         tmpHandle.Set ();
  99                                 Thread.MemoryBarrier ();
 100                                 used = false;
 101                         }
 102                 }
 103
 104                 public void Wait ()
 105                 {
 106                         Wait (CancellationToken.None);
 107                 }
 108
 109                 public bool Wait (int millisecondsTimeout)
 110                 {
 111                         return Wait (millisecondsTimeout, CancellationToken.None);
 112                 }
 113
 114                 public bool Wait (TimeSpan timeout)
 115                 {
 116                         return Wait (CheckTimeout (timeout), CancellationToken.None);
 117                 }
 118
 119                 public void Wait (CancellationToken cancellationToken)
 120                 {
 121                         Wait (Timeout.Infinite, cancellationToken);
 122                 }
 123
 124                 public bool Wait (int millisecondsTimeout, CancellationToken cancellationToken)
 125                 {
 126                         if (millisecondsTimeout < -1)
 127                                 throw new ArgumentOutOfRangeException ("millisecondsTimeout",
 128                                                                        "millisecondsTimeout is a negative number other than -1");
 129                         ThrowIfDisposed ();
 130
 131                         long start = millisecondsTimeout == -1 ? 0 : sw.ElapsedMilliseconds;
 132                         SpinWait wait = new SpinWait ();
 133
 134                         while (state == isNotSet) {
 135                                 cancellationToken.ThrowIfCancellationRequested ();
 136
 137                                 if (millisecondsTimeout > -1 && (sw.ElapsedMilliseconds - start) > millisecondsTimeout)
 138                                         return false;
 139
 140                                 if (wait.Count < spinCount) {
 141                                         wait.SpinOnce ();
 142                                 } else {
 143                                         int waitTime = millisecondsTimeout == -1 ? -1 : Math.Max (millisecondsTimeout - (int)(sw.ElapsedMilliseconds - start) , 1);
 144                                         ThrowIfDisposed ();
 145                                         WaitHandle handle = WaitHandle;
 146                                         if (state == isSet)
 147                                                 return true;
 148                                         ThrowIfDisposed ();
 149
 150                                         if (cancellationToken.CanBeCanceled)
 151                                                 if (WaitHandle.WaitAny (new[] { handle, cancellationToken.WaitHandle }, waitTime, false) == 0)
 152                                                         return true;
 153                                         else
 154                                                 if (handle.WaitOne (waitTime, false))
 155                                                         return true;
 156                                 }
 157                         }
 158
 159                         return true;
 160                 }
 161
 162                 public bool Wait (TimeSpan timeout, CancellationToken cancellationToken)
 163                 {
 164                         return Wait (CheckTimeout (timeout), cancellationToken);
 165                 }
 166
 167                 public WaitHandle WaitHandle {
 168                         get {
 169                                 if (handle != null) {
 170                                         if (state == isSet)
 171                                                 handle.Set ();
 172
 173                                         return handle;
 174                                 }
 175
 176                                 var result = LazyInitializer.EnsureInitialized (ref handle,
 177                                                                                 () => new ManualResetEvent (state == isSet ? true : false));
 178                                 if (state == isSet)
 179                                         result.Set ();
 180
 181                                 return result;
 182                         }
 183                 }
 184
 185                 public void Dispose ()
 186                 {
 187                         Dispose (true);
 188                 }
 189
 190                 protected virtual void Dispose (bool disposing)
 191                 {
 192                         if (!disposed.TryRelaxedSet ())
 193                                 return;
 194                         if (handle != null) {
 195                                 var tmpHandle = Interlocked.Exchange (ref handle, null);
 196                                 if (used) {
 197                                         // A tiny wait (just a few cycles normally) before releasing
 198                                         SpinWait wait = new SpinWait ();
 199                                         while (used)
 200                                                 wait.SpinOnce ();
 201                                 }
 202                                 tmpHandle.Dispose ();
 203                         }
 204                 }
 205
 206                 void ThrowIfDisposed ()
 207                 {
 208                         if (disposed.Value)
 209                                 throw new ObjectDisposedException ("ManualResetEventSlim");
 210                 }
 211
 212                 static int CheckTimeout (TimeSpan timeout)
 213                 {
 214                         try {
 215                                 return checked ((int)timeout.TotalMilliseconds);
 216                         } catch (System.OverflowException) {
 217                                 throw new ArgumentOutOfRangeException ("timeout");
 218                         }
 219                 }
 220         }
 221 }
 222 #endif