pool.h

/* Copyright (c) 2010-2014, Stefan Eilemann <eile@eyescale.ch>
 *
 * 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_POOL_H
#define LUNCHBOX_POOL_H

#include <lunchbox/scopedMutex.h>  // member
#include <lunchbox/spinLock.h>     // member
#include <lunchbox/thread.h>       // thread-safety checks

namespace lunchbox
{
template< typename T, bool locked = false >
class Pool : public boost::noncopyable
{
public:
    Pool() : _lock( locked ? new SpinLock : 0 ) {}

    virtual ~Pool() { flush(); delete _lock; }

    T* alloc()
    {
        ScopedFastWrite mutex( _lock );
        LB_TS_SCOPED( _thread );
        if( _cache.empty( ))
            return new T;

        T* item = _cache.back();
        _cache.pop_back();
        return item;
    }

    void release( T* item )
    {
        ScopedFastWrite mutex( _lock );
        LB_TS_SCOPED( _thread );
        _cache.push_back( item );
    }

    void flush()
    {
        ScopedFastWrite mutex( _lock );
        LB_TS_SCOPED( _thread );
        while( !_cache.empty( ))
        {
            delete _cache.back();
            _cache.pop_back();
        }
    }

private:
    SpinLock* const _lock;
    std::vector< T* > _cache;
    LB_TS_VAR( _thread );
};
}
#endif // LUNCHBOX_POOL_H