instanceCache.h

/* Copyright (c) 2009-2011, 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 CO_INSTANCECACHE_H
#define CO_INSTANCECACHE_H

#include <co/api.h>
#include <co/types.h>

#include <co/base/clock.h>     // member
#include <co/base/lockable.h>  // member
#include <co/base/stdExt.h>    // member
#include <co/base/thread.h>    // member
#include <co/base/uuid.h>      // member

#include <iostream>

namespace co
{
    class InstanceCache
    {
    public:
        CO_API InstanceCache( const uint64_t maxSize = EQ_100MB );

        CO_API ~InstanceCache();

        CO_API bool add( const ObjectVersion& rev, const uint32_t instanceID, 
                  Command& command, const uint32_t usage = 0 );

        void remove( const NodeID& node );

        struct Data
        {
            Data();
            CO_API bool operator != ( const Data& rhs ) const;
            CO_API bool operator == ( const Data& rhs ) const;

            uint32_t masterInstanceID; 
            ObjectDataIStreamDeque versions; 
            CO_API static const Data NONE; 
        };

        CO_API const Data& operator[]( const base::UUID& id );

        CO_API bool release( const base::UUID& id, const uint32_t count );

        CO_API bool erase( const base::UUID& id );

        uint64_t getSize() const { return _size; }

        uint64_t getMaxSize() const { return _maxSize; }

        void expire( const int64_t age );

        bool isEmpty() { return _items->empty(); }

    private:
        struct Item
        {
            Item();
            Data data;
            unsigned used;
            unsigned access;
            NodeID from;

            typedef std::deque< int64_t > TimeDeque;
            TimeDeque times;
        };

        typedef stde::hash_map< base::uint128_t, Item > ItemHash;
        typedef ItemHash::iterator ItemHashIter;
        base::Lockable< ItemHash > _items;

        const uint64_t _maxSize; 
        uint64_t _size;          

        const base::Clock _clock;  

        void _releaseItems( const uint32_t minUsage );
        void _releaseStreams( InstanceCache::Item& item );
        void _releaseStreams( InstanceCache::Item& item, 
                              const int64_t minTime );
        void _releaseFirstStream( InstanceCache::Item& item );
        void _deleteStream( ObjectDataIStream* iStream );

        EQ_TS_VAR( _thread );
    };

    CO_API std::ostream& operator << ( std::ostream&, const InstanceCache& );
}
#endif //CO_INSTANCECACHE_H