/******************************************************************************

 *

 * Name:     gdal_abstractbandblockcache.h

 * Project:  GDAL Core

 * Purpose:  Declaration of GDALAbstractBandBlockCache base class

 * Author:   Frank Warmerdam, warmerdam@pobox.com

 *

 ******************************************************************************

 * Copyright (c) 1998, Frank Warmerdam

 * Copyright (c) 2007-2014, Even Rouault <even dot rouault at spatialys.com>

 *

 * SPDX-License-Identifier: MIT

 ****************************************************************************/

#ifndef GDALABSTRACTBANDBLOCKCACHE_H_INCLUDED

#define GDALABSTRACTBANDBLOCKCACHE_H_INCLUDED

#include "cpl_port.h"

#include "cpl_error.h"

typedef struct _CPLCond CPLCond;

typedef struct _CPLLock CPLLock;

typedef struct _CPLMutex CPLMutex;

class GDALRasterBand;

class GDALRasterBlock;

/* ******************************************************************** */

/*                       GDALAbstractBandBlockCache                     */

/* ******************************************************************** */

//! @cond Doxygen_Suppress

//! This manages how a raster band store its cached block.

// only used by GDALRasterBand implementation.

class GDALAbstractBandBlockCache /* non final */

{

    // List of blocks that can be freed or recycled, and its lock

    CPLLock *hSpinLock = nullptr;

    GDALRasterBlock *psListBlocksToFree = nullptr;

    // Band keep alive counter, and its lock & condition

    CPLCond *hCond = nullptr;

    CPLMutex *hCondMutex = nullptr;

    volatile int nKeepAliveCounter = 0;

    volatile int m_nDirtyBlocks = 0;

    CPL_DISALLOW_COPY_ASSIGN(GDALAbstractBandBlockCache)

  protected:

    explicit GDALAbstractBandBlockCache(GDALRasterBand *poBand);

    GDALRasterBand *poBand;

    int m_nInitialDirtyBlocksInFlushCache = 0;

    int m_nLastTick = -1;

    size_t m_nWriteDirtyBlocksDisabled = 0;

    void FreeDanglingBlocks();

    void UnreferenceBlockBase();

    void StartDirtyBlockFlushingLog();

    void UpdateDirtyBlockFlushingLog();

    void EndDirtyBlockFlushingLog();

  public:

    virtual ~GDALAbstractBandBlockCache();

    GDALRasterBlock *CreateBlock(int nXBlockOff, int nYBlockOff);

    void AddBlockToFreeList(GDALRasterBlock *poBlock);

    void IncDirtyBlocks(int nInc);

    void WaitCompletionPendingTasks();

    void EnableDirtyBlockWriting()

    {

        --m_nWriteDirtyBlocksDisabled;

    }

    void DisableDirtyBlockWriting()

    {

        ++m_nWriteDirtyBlocksDisabled;

    }

    bool HasDirtyBlocks() const

    {

        return m_nDirtyBlocks > 0;

    }

    virtual bool Init() = 0;

    virtual bool IsInitOK() = 0;

    virtual CPLErr FlushCache() = 0;

    virtual CPLErr AdoptBlock(GDALRasterBlock *poBlock) = 0;

    virtual GDALRasterBlock *TryGetLockedBlockRef(int nXBlockOff,

                                                  int nYBlockYOff) = 0;

    virtual CPLErr UnreferenceBlock(GDALRasterBlock *poBlock) = 0;

    virtual CPLErr FlushBlock(int nXBlockOff, int nYBlockOff,

                              int bWriteDirtyBlock) = 0;

};

GDALAbstractBandBlockCache *

GDALArrayBandBlockCacheCreate(GDALRasterBand *poBand);

GDALAbstractBandBlockCache *

GDALHashSetBandBlockCacheCreate(GDALRasterBand *poBand);

//! @endcond

#endif