RegisteredWaitHandle.cs :  » 2.6.4-mono-.net-core » System.Threading » System » Threading » C# / CSharp Open Source

//
// System.Threading.RegisteredWaitHandle.cs
//
// Author:
//   Dick Porter (dick@ximian.com)
//   Lluis Sanchez Gual (lluis@ideary.com)
//
// (C) Ximian, Inc.  http://www.ximian.com
//

//
// Copyright (C) 2004, 2005 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System.Runtime.InteropServices;

namespace System.Threading{
  [ComVisible (true)]
  public sealed class RegisteredWaitHandle : MarshalByRefObject
  {
    WaitHandle _waitObject;
    WaitOrTimerCallback _callback;
    TimeSpan _timeout;
    object _state;
    bool _executeOnlyOnce;
    WaitHandle _finalEvent;
    ManualResetEvent _cancelEvent;
    int _callsInProcess;
    bool _unregistered;

    internal RegisteredWaitHandle (WaitHandle waitObject, WaitOrTimerCallback callback, object state, TimeSpan timeout, bool executeOnlyOnce)
    {
      _waitObject = waitObject;
      _callback = callback;
      _state = state;
      _timeout = timeout;
      _executeOnlyOnce = executeOnlyOnce;
      _finalEvent = null;
      _cancelEvent = new ManualResetEvent (false);
      _callsInProcess = 0;
      _unregistered = false;
    }

    internal void Wait (object state)
    {
      try
      {
        WaitHandle[] waits = new WaitHandle[] {_waitObject, _cancelEvent};
        do 
        {
          int signal = WaitHandle.WaitAny (waits, _timeout, false);
          if (!_unregistered)
          {
            lock (this) { _callsInProcess++; }
            ThreadPool.QueueUserWorkItem (new WaitCallback (DoCallBack), (signal == WaitHandle.WaitTimeout));
          }
        } 
        while (!_unregistered && !_executeOnlyOnce);
      }
      catch {}

      lock (this) {
        _unregistered = true;
        if (_callsInProcess == 0 && _finalEvent != null)
          NativeEventCalls.SetEvent_internal (_finalEvent.Handle);
      }
    }

    private void DoCallBack (object timedOut)
    {
      if (_callback != null)
        _callback (_state, (bool)timedOut); 

      lock (this) 
      {
        _callsInProcess--;
        if (_unregistered && _callsInProcess == 0 && _finalEvent != null)
          NativeEventCalls.SetEvent_internal (_finalEvent.Handle);
      }
    }

    [ComVisible (true)]
    public bool Unregister(WaitHandle waitObject) 
    {
      lock (this) 
      {
        if (_unregistered) return false;
        _finalEvent = waitObject;
        _unregistered = true;
        _cancelEvent.Set();
        return true;
      }
    }

#if ONLY_1_1
    [MonoTODO]
    ~RegisteredWaitHandle() {
      // FIXME
    }
#endif
  }
}