BufferPool.h

/*
 * BufferPool.h
 *
 *  Created on: Mar 15, 2010
 *      Author: green
 */

#ifndef BUFFERPOOL_H_
#define BUFFERPOOL_H_

#include "Common.h"
#include <list>
#include <map>
#include <string>

class PageFileHandle;

class PageBlock {
private:
        friend class BufferPool;

        PageBlock();
        ~PageBlock();

        void clear();
        bool isConsistent();
        int pin();
        int unpin();

        bool isFree_;
        int pinCount_;
        bool isDirty_;
        PageFileHandle* fileHandle_;
        int pageNo_;
        std::list<PageBlock*>::iterator iteratorUnpinned_;
        std::list<PageBlock*>::iterator iteratorFree_;
        const ulong guardPre_;
        char data_[PF_PAGE_SIZE];
        const ulong guardPost_;

        static const ulong GUARD_VALUE;
};




class BufferPool {
public:

        ReturnCode allocateBlock(char **buffer);

        ReturnCode disposeBlock(char *buffer);

        ReturnCode lookupBlock(PageFileHandle* fileHandle, int pageNo, char** data);

        ReturnCode setBlockDirty(PageFileHandle* fileHandle, int pageNo, bool isDirty);

        ReturnCode getBlockDirty(PageFileHandle* fileHandle, int pageNo, bool *isDirty);

        ReturnCode allocateBlock(PageFileHandle* fileHandle, int pageNo, char** data);

        ReturnCode disposeBlock(PageFileHandle* fileHandle, int pageNo);

        ReturnCode disposeAllBlocks(PageFileHandle* fileHandle);

        ReturnCode unpinBlock(PageFileHandle* fileHandle, int pageNo);

        ReturnCode getDirtyPageNumber(PageFileHandle* fileHandle, int* pageNo);

        ReturnCode getPinCount(PageFileHandle* fileHandle, int pageNo, int* pinCount);

        static BufferPool* getInstance();

private:

        BufferPool();

        ~BufferPool();

        PageBlock* getPageBlock(char* data);
        PageBlock* getPageBlock(PageFileHandle* fileHandle, int pageNo);
        void disposePageBlock(PageBlock* pageBlock);
        void setPageBlock(PageBlock* pageBlock, PageFileHandle* fileHandle, int pageNo,
                        char** data);
        bool hasPinnedPage(PageFileHandle* fileHandle);

        PageBlock pageBlocks_[PF_BUFFER_SIZE];          // the pool of page blocks
        std::list<PageBlock*> blocksUnpinned_;          // LRU list of unpinned blocks
        std::list<PageBlock*> blocksFree_;                      // list of free blocks
};

#endif /* PAGEFILE_MANAGER_H_ */

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