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

   1 //
   2 // System.Threading.RegisteredWaitHandle.cs
   3 //
   4 // Author:
   5 //   Dick Porter (dick@ximian.com)
   6 //   Lluis Sanchez Gual (lluis@ideary.com)
   7 //
   8 // (C) Ximian, Inc.  http://www.ximian.com
   9 //
  10
  11 //
  12 // Copyright (C) 2004, 2005 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.Runtime.InteropServices;
  35
  36 namespace System.Threading
  37 {
  38         [ComVisible (true)]
  39         public sealed class RegisteredWaitHandle
  40                 : MarshalByRefObject
  41         {
  42                 WaitHandle _waitObject;
  43                 WaitOrTimerCallback _callback;
  44                 object _state;
  45                 WaitHandle _finalEvent;
  46                 ManualResetEvent _cancelEvent;
  47                 TimeSpan _timeout;
  48                 int _callsInProcess;
  49                 bool _executeOnlyOnce;
  50                 bool _unregistered;
  51
  52                 internal RegisteredWaitHandle (WaitHandle waitObject, WaitOrTimerCallback callback, object state, TimeSpan timeout, bool executeOnlyOnce)
  53                 {
  54                         _waitObject = waitObject;
  55                         _callback = callback;
  56                         _state = state;
  57                         _timeout = timeout;
  58                         _executeOnlyOnce = executeOnlyOnce;
  59                         _finalEvent = null;
  60                         _cancelEvent = new ManualResetEvent (false);
  61                         _callsInProcess = 0;
  62                         _unregistered = false;
  63                 }
  64
  65                 internal void Wait (object state)
  66                 {
  67                         try
  68                         {
  69                                 WaitHandle[] waits = new WaitHandle[] {_waitObject, _cancelEvent};
  70                                 do
  71                                 {
  72                                         int signal = WaitHandle.WaitAny (waits, _timeout, false);
  73                                         if (!_unregistered)
  74                                         {
  75                                                 lock (this) { _callsInProcess++; }
  76                                                 ThreadPool.QueueUserWorkItem (new WaitCallback (DoCallBack), (signal == WaitHandle.WaitTimeout));
  77                                         }
  78                                 }
  79                                 while (!_unregistered && !_executeOnlyOnce);
  80                         }
  81                         catch {}
  82
  83                         lock (this) {
  84                                 _unregistered = true;
  85                                 if (_callsInProcess == 0 && _finalEvent != null)
  86                                         NativeEventCalls.SetEvent_internal (_finalEvent.Handle);
  87                         }
  88                 }
  89
  90                 private void DoCallBack (object timedOut)
  91                 {
  92                         if (_callback != null) {
  93                                 try {
  94                                         _callback (_state, (bool)timedOut);
  95                                 } catch {}
  96                         }
  97
  98                         lock (this)
  99                         {
 100                                 _callsInProcess--;
 101                                 if (_unregistered && _callsInProcess == 0 && _finalEvent != null)
 102                                         NativeEventCalls.SetEvent_internal (_finalEvent.Handle);
 103                         }
 104                 }
 105
 106                 [ComVisible (true)]
 107                 public bool Unregister(WaitHandle waitObject)
 108                 {
 109                         lock (this)
 110                         {
 111                                 if (_unregistered) return false;
 112                                 _finalEvent = waitObject;
 113                                 _unregistered = true;
 114                                 _cancelEvent.Set();
 115                                 return true;
 116                         }
 117                 }
 118
 119         }
 120 }