src/AsyncFramework/WaitableEvent.h

   1 /***************************************************************************
   2  *   Copyright (C) 2009 by Stefan Fuhrmann                                 *
   3  *   stefanfuhrmann@alice-dsl.de                                           *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  19  ***************************************************************************/
  20
  21 #pragma once
  22
  23 namespace async
  24 {
  25
  26 /**
  27 * A waitable event that can be signaled only once.
  28 * Also, only one waiting thread is allowed.
  29 *
  30 * This is a more lightweight implementation than
  31 * \ref CWaitableEvent as the \ref event handle is
  32 * only allocated if \ref WaitFor() requires it.
  33 */
  34
  35 class COneShotEvent
  36 {
  37 private:
  38
  39     /// OS-specific event object
  40
  41     HANDLE event;
  42     volatile LONG state;
  43
  44 public:
  45
  46     /// construction / destruction: manage event handle
  47
  48     COneShotEvent();
  49     ~COneShotEvent();
  50
  51     /// eventing interface
  52
  53     void Set();
  54     bool Test() const;
  55     void WaitFor();
  56
  57     /// returns false in case of a timeout
  58
  59     bool WaitForEndOrTimeout(DWORD milliSeconds);
  60 };
  61
  62 /**
  63 * A waitable event that must be reset manually.
  64 * This implementation uses a global pool of event
  65 * handles to minimize OS handle creation and destruction
  66 * overhead.
  67 */
  68
  69 class CWaitableEvent
  70 {
  71 private:
  72
  73     /// OS-specific event object
  74
  75     HANDLE event;
  76
  77 public:
  78
  79     /// construction / destruction: manage event handle
  80
  81     CWaitableEvent();
  82     ~CWaitableEvent();
  83
  84     /// eventing interface
  85
  86     void Set();
  87     void Reset();
  88     bool Test() const;
  89     void WaitFor();
  90
  91     /// returns false in case of a timeout
  92
  93     bool WaitForEndOrTimeout(DWORD milliSeconds);
  94 };
  95
  96 }