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/*
* psync.h
*
* Abstract synchronisation semaphore class.
*
* Portable Windows 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): ______________________________________.
*
* $Log: psync.h,v $
* Revision 1.4 2005/11/25 03:43:47 csoutheren
* Fixed function argument comments to be compatible with Doxygen
*
* Revision 1.3 2005/11/14 22:29:13 csoutheren
* Reverted Wait and Signal to non-const - there is no way we can guarantee that all
* descendant classes everywhere will be changed over, so we have to keep the
* original API
*
* Revision 1.2 2005/11/04 06:56:10 csoutheren
* Added new class PSync as abstract base class for all mutex/sempahore classes
* Changed PCriticalSection to use Wait/Signal rather than Enter/Leave
* Changed Wait/Signal to be const member functions
* Renamed PMutex to PTimedMutex and made PMutex synonym for PCriticalSection.
* This allows use of very efficient mutex primitives in 99% of cases where timed waits
* are not needed
*
* Revision 1.1 2005/11/04 06:34:20 csoutheren
* Added new class PSync as abstract base class for all mutex/sempahore classes
* Changed PCriticalSection to use Wait/Signal rather than Enter/Leave
* Changed Wait/Signal to be const member functions
* Renamed PMutex to PTimedMutex and made PMutex synonym for PCriticalSection.
* This allows use of very efficient mutex primitives in 99% of cases where timed waits
* are not needed
*
*/
#ifndef _PSYNC
#define _PSYNC
#ifdef P_USE_PRAGMA
#pragma interface
#endif
#include <ptlib/contain.h>
class PSync : public PObject
{
public:
/**@name Operations */
//@{
/**Block until the synchronisation object is available
*/
virtual void Wait() = 0;
/**Signal that the synchronisation object is available
*/
virtual void Signal() = 0;
//@}
};
/**This class waits for the semaphore on construction and automatically
signals the semaphore on destruction. Any descendent of PSemaphore
may be used.
This is very usefull for constructs such as:
\begin{verbatim}
void func()
{
PWaitAndSignal mutexWait(myMutex);
if (condition)
return;
do_something();
if (other_condition)
return;
do_something_else();
}
\end{verbatim}
*/
class PWaitAndSignal {
public:
/**Create the semaphore wait instance.
This will wait on the specified semaphore using the #Wait()# function
before returning.
*/
inline PWaitAndSignal(
const PSync & sem, ///< Semaphore descendent to wait/signal.
BOOL wait = TRUE ///< Wait for semaphore before returning.
) : sync((PSync &)sem)
{ if (wait) sync.Wait(); }
/** Signal the semaphore.
This will execute the Signal() function on the semaphore that was used
in the construction of this instance.
*/
~PWaitAndSignal()
{ sync.Signal(); }
protected:
PSync & sync;
};
#endif // PSYNC
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