/************************************************************************* * * $RCSfile: writeguard.hxx,v $ * * $Revision: 1.4 $ * * last change: $Author: as $ $Date: 2001-06-11 10:25:40 $ * * 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. * * This library is distributed in the hope that it will be useful, * 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 * License at http://www.openoffice.org/license.html. * * Software provided under this License is provided on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, * WITHOUT LIMITATION, WARRANTIES THAT THE SOFTWARE IS FREE OF DEFECTS, * MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE, OR NON-INFRINGING. * See the License for the specific provisions governing your rights and * obligations concerning the Software. * * The Initial Developer of the Original Code is: Sun Microsystems, Inc. * * Copyright: 2000 by Sun Microsystems, Inc. * * All Rights Reserved. * * Contributor(s): _______________________________________ * * ************************************************************************/ #ifndef __FRAMEWORK_THREADHELP_WRITEGUARD_HXX_ #define __FRAMEWORK_THREADHELP_WRITEGUARD_HXX_ //_________________________________________________________________________________________________________________ // my own includes //_________________________________________________________________________________________________________________ #ifndef __FRAMEWORK_THREADHELP_INONCOPYABLE_H_ #include #endif #ifndef __FRAMEWORK_THREADHELP_IRWLOCK_H_ #include #endif //#ifndef __FRAMEWORK_THREADHELP_THREADHELPBASE_HXX_ //#include //#endif //_________________________________________________________________________________________________________________ // interface includes //_________________________________________________________________________________________________________________ //_________________________________________________________________________________________________________________ // other includes //_________________________________________________________________________________________________________________ //_________________________________________________________________________________________________________________ // namespace //_________________________________________________________________________________________________________________ namespace framework{ //_________________________________________________________________________________________________________________ // const //_________________________________________________________________________________________________________________ //_________________________________________________________________________________________________________________ // declarations //_________________________________________________________________________________________________________________ /*-************************************************************************************************************//** @short implement a guard to set write locks @descr This guard should be used to set a lock for reading AND writing object internal member. 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 a) To prevent us against wrong using, the default ctor, copy ctor and the =operator are maked private! b) Use interface "IRWLock" of set LockHelper only - because we must support a finer granularity of locking. Interface "IMutex" should be used by easier guard implementations ... like "ResetableGuard"! @implements - @base INonCopyable @devstatus ready to use *//*-*************************************************************************************************************/ class WriteGuard : 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 @return - @onerror - *//*-*****************************************************************************************************/ inline WriteGuard( IRWLock* pLock ) : m_pLock ( pLock ) , m_eMode ( E_NOLOCK ) { lock(); } //********************************************************************************************************* inline WriteGuard( IRWLock& rLock ) : m_pLock ( &rLock ) , m_eMode ( E_NOLOCK ) { lock(); } /*-****************************************************************************************************//** @short dtor @descr We unlock the used lock member automaticly if user forget it. @seealso - @param - @return - @onerror - *//*-*****************************************************************************************************/ inline ~WriteGuard() { unlock(); } /*-****************************************************************************************************//** @short set write lock @descr Call this method to set the write lock. The call will block till all current threads are synchronized! @seealso method unlock() @param - @return - @onerror - *//*-*****************************************************************************************************/ inline void lock() { switch( m_eMode ) { case E_NOLOCK : { // Acquire write access and set return state. // Mode is set later if it was successful! m_pLock->acquireWriteAccess(); m_eMode = E_WRITELOCK; } break; case E_READLOCK : { // User has downgrade to read access before! // We must release it before we can set a new write access! m_pLock->releaseReadAccess(); m_pLock->acquireWriteAccess(); m_eMode = E_WRITELOCK; } break; } } /*-****************************************************************************************************//** @short unset write 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 - *//*-*****************************************************************************************************/ inline void unlock() { switch( m_eMode ) { case E_READLOCK : { // User has downgraded to a read lock before! // => There isn't realy a write lock ... m_pLock->releaseReadAccess(); m_eMode = E_NOLOCK; } break; case E_WRITELOCK : { m_pLock->releaseWriteAccess(); m_eMode = E_NOLOCK; } break; } } /*-****************************************************************************************************//** @short downgrade write access to read access without new blocking! @descr If this write lock is set you can change it to a "read lock". An "upgrade" is the same like new calling "lock()"! @seealso - @param - @return - @onerror - *//*-*****************************************************************************************************/ inline void downgrade() { if( m_eMode == E_WRITELOCK ) { m_pLock->downgradeWriteAccess(); m_eMode = E_READLOCK; } } /*-****************************************************************************************************//** @short return internal states @descr For user they dont know what they are doing ... @seealso - @param - @return Current set lock mode. @onerror No error should occure. *//*-*****************************************************************************************************/ inline ELockMode getMode() const { return m_eMode; } //------------------------------------------------------------------------------------------------------------- // 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 - *//*-*****************************************************************************************************/ WriteGuard(); //------------------------------------------------------------------------------------------------------------- // private member //------------------------------------------------------------------------------------------------------------- private: IRWLock* m_pLock ; /// reference to lock-member of protected object ELockMode m_eMode ; /// protection against multiple lock calls without unlock and difference between supported lock modi }; // class WriteGuard } // namespace framework #endif // #ifndef __FRAMEWORK_THREADHELP_WRITEGUARD_HXX_