scopedMutex.h

/* Copyright (c) 2006-2012, Stefan Eilemann <eile@equalizergraphics.com>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef LUNCHBOX_SCOPEDMUTEX_H
#define LUNCHBOX_SCOPEDMUTEX_H

#include <lunchbox/condition.h>   // used in inline method
#include <lunchbox/lock.h>        // used in inline method
#include <lunchbox/lockable.h>    // used in inline method
#include <lunchbox/types.h>

namespace lunchbox
{
    class WriteOp;
    class ReadOp;

    template< class L, class T > struct ScopedMutexLocker {};
    template< class L > struct ScopedMutexLocker< L, WriteOp >
    {
        static inline void set( L& lock ) { lock.set(); }
        static inline void unset( L& lock ) { lock.unset(); }
    };
    template< class L > struct ScopedMutexLocker< L, ReadOp >
    {
        static inline void set( L& lock ) { lock.setRead(); }
        static inline void unset( L& lock ) { lock.unsetRead(); }
    };
    template<> struct ScopedMutexLocker< Condition, WriteOp >
    {
        static inline void set( Condition& cond ) { cond.lock(); }
        static inline void unset( Condition& cond ) { cond.unlock(); }
    };
    template< class L = Lock, class T = WriteOp >
    class ScopedMutex
    {
        typedef ScopedMutexLocker< L, T > LockTraits;

    public:
        explicit ScopedMutex( L* lock ) : _lock( lock )
            { if( lock ) LockTraits::set( *lock ); }

        explicit ScopedMutex( L& lock ) : _lock( &lock )
            { LockTraits::set( lock ); }

        ScopedMutex( const ScopedMutex& rhs ) : _lock( rhs._lock )
            { const_cast< ScopedMutex& >( rhs )._lock = 0; }

        ScopedMutex& operator = ( ScopedMutex& rhs )
            {
                if( this != &rhs )
                {
                    _lock = rhs._lock;
                    rhs._lock = 0;
                }
                return *this;
            }

        template< typename LB > explicit ScopedMutex( const LB& lockable )
                : _lock( &lockable.lock ) { LockTraits::set( lockable.lock ); }

        ~ScopedMutex() { leave(); }

        void leave() { if( _lock ) LockTraits::unset( *_lock ); _lock = 0; }

    private:
        ScopedMutex();
        L* _lock;
    };

    typedef ScopedMutex< SpinLock, ReadOp > ScopedFastRead;

    typedef ScopedMutex< SpinLock, WriteOp > ScopedFastWrite;

    typedef ScopedMutex< Lock, ReadOp > ScopedRead;

    typedef ScopedMutex< Lock, WriteOp > ScopedWrite;

    typedef ScopedMutex< Condition, WriteOp > ScopedCondition;
}
#endif //LUNCHBOX_SCOPEDMUTEX_H