// BlockCache.h
//
// Copyright (c) 2003, Ingo Weinhold (bonefish@cs.tu-berlin.de)
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// This program 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 General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
// You can alternatively use *this file* under the terms of the the MIT
// license included in this package.

#ifndef BLOCK_CACHE_H
#define BLOCK_CACHE_H

#include <SupportDefs.h>

#include "List.h"
#include "Locker.h"

class Block;
class Node;

class BlockCache {
public:
        BlockCache();
        ~BlockCache();

        status_t Init(int device, uint64 blockCount, uint32 blockSize);

        int GetDevice() const { return fDevice; }
        uint32 GetBlockSize() const { return fBlockSize; }
        off_t GetBlockCount() const { return fBlockCount; }

        status_t GetBlock(Block *block);
        status_t GetBlock(uint64 number, Block **block);
        void PutBlock(Block *block);

private:
        Block *_FindBlock(uint64 number);
        status_t _ReadBlock(uint64 number, Block **block);


        friend class Block;
        void *_GetBlock(off_t number) const;
        void _ReleaseBlock(off_t number, void *data) const;

private:
        int                                             fDevice;
        uint32                                  fBlockSize;
        uint64                                  fBlockCount;
        Locker                                  fLock;
        List<Block*>                    fBlocks;
        void*                                   fCacheHandle;
        // statistics
        int64                                   fReads;
        mutable int64                   fBlockGets;
        mutable int64                   fBlockReleases;
};

#endif  // BLOCK_CACHE_H