psync.h

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/*
 * psync.h
 *
 * Abstract synchronisation semaphore class.
 *
 * Portable Tools Library
 *
 * Copyright (c) 1993-1998 Equivalence Pty. Ltd.
 * Copyright (c) 2005 Post Increment
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is Portable Windows Library.
 *
 * The Initial Developer of the Original Code is Equivalence Pty. Ltd.
 *
 * Portions are Copyright (C) 1993 Free Software Foundation, Inc.
 * All Rights Reserved.
 *
 * Contributor(s): ______________________________________.
 *
 * $Revision: 28065 $
 * $Author: rjongbloed $
 * $Date: 2012-07-19 21:01:53 +1000 (Thu, 19 Jul 2012) $
 */

#ifndef PTLIB_SYNC_H
#define PTLIB_SYNC_H

#ifdef P_USE_PRAGMA
#pragma interface
#endif

#include <ptlib/contain.h>
#include <ptlib/object.h>


class PTimeInterval;


class PSync : public PObject
{
  public:
    PSync() { }

    virtual void Wait() = 0;

    virtual PBoolean Wait(
      const PTimeInterval & timeout // Amount of time to wait.
    ) = 0;

    virtual void Signal() = 0;

  private:
    PSync(const PSync &) : PObject() { }
    void operator=(const PSync &) { }
};


class PSyncNULL : public PSync
{
  public:
    virtual void Wait() { }
    virtual PBoolean Wait(const PTimeInterval &) { return true; }
    virtual void Signal() { }

  private:
    PSyncNULL(const PSyncNULL &) : PSync() { }
    void operator=(const PSyncNULL &) { }
};


class PWaitAndSignal {
  public:
    inline PWaitAndSignal(
      const PSync & sem,   
      PBoolean wait = true    
    ) : sync((PSync &)sem)
    { if (wait) sync.Wait(); }

    ~PWaitAndSignal()
    { sync.Signal(); }

  protected:
    PSync & sync;
};


#endif // PTLIB_SYNC_H


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