libreoffice/framework/inc/threadhelp/readguard.hxx

/*************************************************************************
 *
 *  $RCSfile: readguard.hxx,v $
 *
 *  $Revision: 1.2 $
 *
 *  last change: $Author: as $ $Date: 2001-04-04 13:28:33 $
 *
 *  The Contents of this file are made available subject to the terms of
 *  either of the following licenses
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 *         - GNU Lesser General Public License Version 2.1
 *         - Sun Industry Standards Source License Version 1.1
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 *  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
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 *  Lesser General Public License for more details.
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 *
 *
 *  Sun Industry Standards Source License Version 1.1
 *  =================================================
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 *  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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 ************************************************************************/

#ifndef __FRAMEWORK_THREADHELP_READGUARD_HXX_
#define __FRAMEWORK_THREADHELP_READGUARD_HXX_

//_________________________________________________________________________________________________________________
//  my own includes
//_________________________________________________________________________________________________________________

#ifndef __FRAMEWORK_THREADHELP_INONCOPYABLE_H_
#include <threadhelp/inoncopyable.h>
#endif

#ifndef __FRAMEWORK_THREADHELP_IRWLOCK_H_
#include <threadhelp/irwlock.h>
#endif

//_________________________________________________________________________________________________________________
//  interface includes
//_________________________________________________________________________________________________________________

//_________________________________________________________________________________________________________________
//  other includes
//_________________________________________________________________________________________________________________

//_________________________________________________________________________________________________________________
//  namespace
//_________________________________________________________________________________________________________________

namespace framework{

//_________________________________________________________________________________________________________________
//  const
//_________________________________________________________________________________________________________________

//_________________________________________________________________________________________________________________
//  declarations
//_________________________________________________________________________________________________________________

/*-************************************************************************************************************//**
    @short          implement a guard to set read locks
    @descr          This guard should be used to set a lock for reading object internal member.
                    Nobody can control it but don't use member after successfuly locking for writing!
                    We never need a own mutex to safe our internal member access - because
                    a guard is used as function-local member only. There exist no multithreaded access to it realy ...

    @attention      1) To prevent us against wrong using, the default ctor, copy ctor and the =operator are maked private!
                    2) Every method support a return value "eReason". Use this value to react for refused lock-calls!
                       This means: You can't work with this object! We are not ready for working yet ...
                       React for that in a right way.
                       (see "irwlock.h" for further informations)

    @implements     -
    @base           INonCopyAble

    @devstatus      ready to use
*//*-*************************************************************************************************************/

class ReadGuard : private INonCopyAble
{
    //-------------------------------------------------------------------------------------------------------------
    //  public methods
    //-------------------------------------------------------------------------------------------------------------
    public:

        /*-****************************************************************************************************//**
            @short      ctor
            @descr      These ctors initialize the guard with a reference to used lock member of object to protect.
                        Null isn't allowed as value!

            @seealso    -

            @param      "pLock",    reference to used lock member of object to protect
            @param      "rLock",    reference to used lock member of object to protect
            @param      "eReason",  return value if call was refused
            @return     -

            @onerror    -
        *//*-*****************************************************************************************************/

        ReadGuard(  IRWLock*        pLock   ,
                    ERejectReason&  eReason );
        ReadGuard(  IRWLock&        rLock   ,
                    ERejectReason&  eReason );

        /*-****************************************************************************************************//**
            @short      dtor
            @descr      We unlock the used lock member automaticly if user forget it.

            @seealso    -

            @param      -
            @return     -

            @onerror    -
        *//*-*****************************************************************************************************/

        ~ReadGuard();

        /*-****************************************************************************************************//**
            @short      set read lock
            @descr      Call this method to set the read lock. The call will block till all current threads are synchronized!
                        If the return value right you can work ... If return value is different from E_NONE you have no permission!
                        May be the lock call was refused and must be handled in another way!

            @seealso    method unlock()

            @param      "eReason", return the reason for rejected calls
            @return     -

            @onerror    -
        *//*-*****************************************************************************************************/

        void lock( ERejectReason& eReason );

        /*-****************************************************************************************************//**
            @short      unset read lock
            @descr      Call this method to unlock the rw-lock temp.!
                        Normaly we do it at dtor automaticly for you ...

            @seealso    method lock()

            @param      -
            @return     -

            @onerror    -
        *//*-*****************************************************************************************************/

        void unlock();

        /*-****************************************************************************************************//**
            @short      return internal lock state
            @descr      For user they dont know what they are doing there ...

            @seealso    -

            @param      -
            @return     -

            @onerror    -
        *//*-*****************************************************************************************************/

        sal_Bool isLocked() const;

    //-------------------------------------------------------------------------------------------------------------
    //  private methods
    //-------------------------------------------------------------------------------------------------------------
    private:

        /*-****************************************************************************************************//**
            @short      disable using of these functions!
            @descr      It's not allowed to use this methods. Different problem can occure otherwise.
                        Thats why we disable it by make it private.

            @seealso    other ctor

            @param      -
            @return     -

            @onerror    -
        *//*-*****************************************************************************************************/

        ReadGuard();

    //-------------------------------------------------------------------------------------------------------------
    //  private member
    //-------------------------------------------------------------------------------------------------------------
    private:

        IRWLock*    m_pLock     ;   /// refrence to lock-member of protected object
        sal_Bool    m_bLocked   ;   /// protection against multiple lock calls without unlock!

};      //  class ReadGuard

}       //  namespace framework

#endif  //  #ifndef __FRAMEWORK_THREADHELP_READGUARD_HXX_