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 #if !MOONLIGHT
  41                 : MarshalByRefObject
  42 #endif
  43         {
  44                 WaitHandle _waitObject;
  45                 WaitOrTimerCallback _callback;
  46                 object _state;
  47                 WaitHandle _finalEvent;
  48                 ManualResetEvent _cancelEvent;
  49                 TimeSpan _timeout;
  50                 int _callsInProcess;
  51                 bool _executeOnlyOnce;
  52                 bool _unregistered;
  53
  54                 internal RegisteredWaitHandle (WaitHandle waitObject, WaitOrTimerCallback callback, object state, TimeSpan timeout, bool executeOnlyOnce)
  55                 {
  56                         _waitObject = waitObject;
  57                         _callback = callback;
  58                         _state = state;
  59                         _timeout = timeout;
  60                         _executeOnlyOnce = executeOnlyOnce;
  61                         _finalEvent = null;
  62                         _cancelEvent = new ManualResetEvent (false);
  63                         _callsInProcess = 0;
  64                         _unregistered = false;
  65                 }
  66
  67                 internal void Wait (object state)
  68                 {
  69                         try
  70                         {
  71                                 WaitHandle[] waits = new WaitHandle[] {_waitObject, _cancelEvent};
  72                                 do
  73                                 {
  74                                         int signal = WaitHandle.WaitAny (waits, _timeout, false);
  75                                         if (!_unregistered)
  76                                         {
  77                                                 lock (this) { _callsInProcess++; }
  78                                                 ThreadPool.QueueUserWorkItem (new WaitCallback (DoCallBack), (signal == WaitHandle.WaitTimeout));
  79                                         }
  80                                 }
  81                                 while (!_unregistered && !_executeOnlyOnce);
  82                         }
  83                         catch {}
  84
  85                         lock (this) {
  86                                 _unregistered = true;
  87                                 if (_callsInProcess == 0 && _finalEvent != null)
  88                                         NativeEventCalls.SetEvent_internal (_finalEvent.Handle);
  89                         }
  90                 }
  91
  92                 private void DoCallBack (object timedOut)
  93                 {
  94                         if (_callback != null) {
  95                                 try {
  96                                         _callback (_state, (bool)timedOut);
  97                                 } catch {}
  98                         }
  99
 100                         lock (this)
 101                         {
 102                                 _callsInProcess--;
 103                                 if (_unregistered && _callsInProcess == 0 && _finalEvent != null)
 104                                         NativeEventCalls.SetEvent_internal (_finalEvent.Handle);
 105                         }
 106                 }
 107
 108                 [ComVisible (true)]
 109                 public bool Unregister(WaitHandle waitObject)
 110                 {
 111                         lock (this)
 112                         {
 113                                 if (_unregistered) return false;
 114                                 _finalEvent = waitObject;
 115                                 _unregistered = true;
 116                                 _cancelEvent.Set();
 117                                 return true;
 118                         }
 119                 }
 120
 121         }
 122 }