office-gobmx/framework/inc/threadhelp/irwlock.h

/*************************************************************************
 *
 *  $RCSfile: irwlock.h,v $
 *
 *  $Revision: 1.3 $
 *
 *  last change: $Author: as $ $Date: 2001-05-02 13:00:41 $
 *
 *  The Contents of this file are made available subject to the terms of
 *  either of the following licenses
 *
 *         - GNU Lesser General Public License Version 2.1
 *         - Sun Industry Standards Source License Version 1.1
 *
 *  Sun Microsystems Inc., October, 2000
 *
 *  GNU Lesser General Public License Version 2.1
 *  =============================================
 *  Copyright 2000 by Sun Microsystems, Inc.
 *  901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License version 2.1, as published by the Free Software Foundation.
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 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA  02111-1307  USA
 *
 *
 *  Sun Industry Standards Source License Version 1.1
 *  =================================================
 *  The contents of this file are subject to the Sun Industry Standards
 *  Source License Version 1.1 (the "License"); You may not use this file
 *  except in compliance with the License. You may obtain a copy of the
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 *  See the License for the specific provisions governing your rights and
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 *  The Initial Developer of the Original Code is: Sun Microsystems, Inc.
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 *  Copyright: 2000 by Sun Microsystems, Inc.
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 ************************************************************************/

#ifndef __FRAMEWORK_THREADHELP_IRWLOCK_H_
#define __FRAMEWORK_THREADHELP_IRWLOCK_H_

//_________________________________________________________________________________________________________________
//  includes
//_________________________________________________________________________________________________________________

#ifndef __FRAMEWORK_GENERAL_H_
#include <general.h>
#endif

#ifndef _SAL_TYPES_H_
#include <sal/types.h>
#endif

//_________________________________________________________________________________________________________________
//  namespace
//_________________________________________________________________________________________________________________

namespace framework{

//_________________________________________________________________________________________________________________
//  declarations
//_________________________________________________________________________________________________________________

/*-************************************************************************************************************//**
    @descr          A guard (specialy a write guard) support different internal working states.
                    His lock can set for reading or writing/reading! Or he was unlocked by user ...
*//*-*************************************************************************************************************/
enum ELockMode
{
    E_NOLOCK    ,
    E_READLOCK  ,
    E_WRITELOCK
};

/*-************************************************************************************************************//**
    @descr          We implement two guards for using an rw-lock. But if you wish to implement
                    different rw-locks to you will have problems by using with same guard implementation!
                    Thats why we define this "pure virtual base class" ...
                    All rw-locks must support this base interface for working and all guard must use this one too!
*//*-*************************************************************************************************************/
class IRWLock
{
    //-------------------------------------------------------------------------------------------------------------
    //  public methods
    //-------------------------------------------------------------------------------------------------------------
    public:

        /*-****************************************************************************************************//**
            @descr      The dtor isn't realy important ... but if you whish to use derived classes
                        with any pointer ... you must have it!
        *//*-*****************************************************************************************************/
        virtual ~IRWLock() {}

        /*-****************************************************************************************************//**
            @descr      These functions must be supported by a derived class!
                            acquireReadAccess()     -try to register thread as reader
                            releaseReadAccess()     -unregister thread as reader
                            acquireWriteAccess()    -try to register thread as writer
                            releaseWriteAccess()    -unregister thread as writer
                            downgradeWriteAccess()  -make writer to reader
        *//*-*****************************************************************************************************/
        virtual void SAL_CALL acquireReadAccess    () = 0;
        virtual void SAL_CALL releaseReadAccess    () = 0;
        virtual void SAL_CALL acquireWriteAccess   () = 0;
        virtual void SAL_CALL releaseWriteAccess   () = 0;
        virtual void SAL_CALL downgradeWriteAccess () = 0;

};      //  class IRWLock

}       //  namespace framework

#endif  //  #ifndef __FRAMEWORK_THREADHELP_IRWLOCK_H_