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

 *

 * Project:  GeoTIFF Driver

 * Purpose:  Implement system hook functions for libtiff on top of CPL/VSI,

 *           including > 2GB support.  Based on tif_unix.c from libtiff

 *           distribution.

 * Author:   Frank Warmerdam, warmerdam@pobox.com

 *

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

 * Copyright (c) 2005, Frank Warmerdam, warmerdam@pobox.com

 * Copyright (c) 2010-2012, Even Rouault <even dot rouault at spatialys.com>

 *

 * SPDX-License-Identifier: MIT

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

// TIFF Library UNIX-specific Routines.

#include "cpl_port.h"

#include "tifvsi.h"

#include <assert.h>

#include <string.h>

#include <cerrno>

#if HAVE_FCNTL_H

#include <fcntl.h>

#endif

#include "cpl_conv.h"

#include "cpl_vsi.h"

#include "cpl_string.h"

// We avoid including xtiffio.h since it drags in the libgeotiff version

// of the VSI functions.

#ifdef RENAME_INTERNAL_LIBGEOTIFF_SYMBOLS

#include "gdal_libgeotiff_symbol_rename.h"

#endif

#include "xtiffio.h"

#include <limits>

#if (TIFFLIB_VERSION > 20220520) || defined(INTERNAL_LIBTIFF)  // > 4.4.0

#define SUPPORTS_LIBTIFF_OPEN_OPTIONS

extern int GTiffWarningHandlerExt(TIFF *tif, void *user_data,

                                  const char *module, const char *fmt,

                                  va_list ap);

extern int GTiffErrorHandlerExt(TIFF *tif, void *user_data, const char *module,

                                const char *fmt, va_list ap);

#endif

constexpr int BUFFER_SIZE = 65536;

struct GDALTiffHandle;

struct GDALTiffHandleShared

{

    VSILFILE *fpL;

    bool bReadOnly;

    bool bLazyStrileLoading;

    char *pszName;

    GDALTiffHandle *psActiveHandle;  // only used on the parent

    int nUserCounter;

    bool bAtEndOfFile;

    vsi_l_offset nFileLength;

};

struct GDALTiffHandle

{

    bool bFree;

    GDALTiffHandle *psParent;  // nullptr for the parent itself

    GDALTiffHandleShared *psShared;

    GByte *abyWriteBuffer;

    int nWriteBufferSize;

    // For pseudo-mmap'ed /vsimem/ file

    vsi_l_offset nDataLength;

    void *pBase;

    // If we pre-cached data (typically from /vsicurl/ )

    int nCachedRanges;

    void **ppCachedData;

    vsi_l_offset *panCachedOffsets;

    size_t *panCachedSizes;

};

static bool GTHFlushBuffer(thandle_t th);

static void SetActiveGTH(GDALTiffHandle *psGTH)

{

    auto psShared = psGTH->psShared;

    if (psShared->psActiveHandle != psGTH)

    {

        if (psShared->psActiveHandle != nullptr)

        {

            GTHFlushBuffer(static_cast<thandle_t>(psShared->psActiveHandle));

        }

        psShared->psActiveHandle = psGTH;

    }

}

void *VSI_TIFFGetCachedRange(thandle_t th, vsi_l_offset nOffset, size_t nSize)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    for (int i = 0; i < psGTH->nCachedRanges; i++)

    {

        if (nOffset >= psGTH->panCachedOffsets[i] &&

            nOffset + nSize <=

                psGTH->panCachedOffsets[i] + psGTH->panCachedSizes[i])

        {

            return static_cast<GByte *>(psGTH->ppCachedData[i]) +

                   (nOffset - psGTH->panCachedOffsets[i]);

        }

        if (nOffset < psGTH->panCachedOffsets[i])

            break;

    }

    return nullptr;

}

static tsize_t _tiffReadProc(thandle_t th, tdata_t buf, tsize_t size)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    // SetActiveGTH(psGTH);

    if (psGTH->nCachedRanges)

    {

        const vsi_l_offset nCurOffset = VSIFTellL(psGTH->psShared->fpL);

        void *data =

            VSI_TIFFGetCachedRange(th, nCurOffset, static_cast<size_t>(size));

        if (data)

        {

            memcpy(buf, data, size);

            VSIFSeekL(psGTH->psShared->fpL, nCurOffset + size, SEEK_SET);

            return size;

        }

    }

#ifdef DEBUG_VERBOSE_EXTRA

    CPLDebug("GTiff", "Reading %d bytes at offset " CPL_FRMT_GUIB,

             static_cast<int>(size), VSIFTellL(psGTH->psShared->fpL));

#endif

    return VSIFReadL(buf, 1, size, psGTH->psShared->fpL);

}

static bool GTHFlushBuffer(thandle_t th)

{

    GDALTiffHandle *psGTH = static_cast<GDALTiffHandle *>(th);

    bool bRet = true;

    if (psGTH->abyWriteBuffer && psGTH->nWriteBufferSize)

    {

        const tsize_t nRet =

            VSIFWriteL(psGTH->abyWriteBuffer, 1, psGTH->nWriteBufferSize,

                       psGTH->psShared->fpL);

        bRet = nRet == psGTH->nWriteBufferSize;

        if (!bRet)

        {

            TIFFErrorExt(th, "_tiffWriteProc", "%s", VSIStrerror(errno));

        }

        psGTH->nWriteBufferSize = 0;

    }

    return bRet;

}

static tsize_t _tiffWriteProc(thandle_t th, tdata_t buf, tsize_t size)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    SetActiveGTH(psGTH);

    // If we have a write buffer and are at end of file, then accumulate

    // the bytes until the buffer is full.

    if (psGTH->psShared->bAtEndOfFile && psGTH->abyWriteBuffer)

    {

        const GByte *pabyData = reinterpret_cast<GByte *>(buf);

        tsize_t nRemainingBytes = size;

        while (true)

        {

            if (psGTH->nWriteBufferSize + nRemainingBytes <= BUFFER_SIZE)

            {

                memcpy(psGTH->abyWriteBuffer + psGTH->nWriteBufferSize,

                       pabyData, nRemainingBytes);

                psGTH->nWriteBufferSize += static_cast<int>(nRemainingBytes);

                if (psGTH->psShared->bAtEndOfFile)

                {

                    psGTH->psShared->nFileLength += size;

                }

                return size;

            }

            int nAppendable = BUFFER_SIZE - psGTH->nWriteBufferSize;

            memcpy(psGTH->abyWriteBuffer + psGTH->nWriteBufferSize, pabyData,

                   nAppendable);

            const tsize_t nRet = VSIFWriteL(psGTH->abyWriteBuffer, 1,

                                            BUFFER_SIZE, psGTH->psShared->fpL);

            psGTH->nWriteBufferSize = 0;

            if (nRet != BUFFER_SIZE)

            {

                TIFFErrorExt(th, "_tiffWriteProc", "%s", VSIStrerror(errno));

                return 0;

            }

            pabyData += nAppendable;

            nRemainingBytes -= nAppendable;

        }

    }

    const tsize_t nRet = VSIFWriteL(buf, 1, size, psGTH->psShared->fpL);

    if (nRet < size)

    {

        TIFFErrorExt(th, "_tiffWriteProc", "%s", VSIStrerror(errno));

    }

    if (psGTH->psShared->bAtEndOfFile)

    {

        psGTH->psShared->nFileLength += nRet;

    }

    return nRet;

}

static toff_t _tiffSeekProc(thandle_t th, toff_t off, int whence)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    SetActiveGTH(psGTH);

    // Optimization: if we are already at end, then no need to

    // issue a VSIFSeekL().

    if (whence == SEEK_END)

    {

        if (psGTH->psShared->bAtEndOfFile)

        {

            return static_cast<toff_t>(psGTH->psShared->nFileLength);

        }

        if (VSIFSeekL(psGTH->psShared->fpL, off, whence) != 0)

        {

            TIFFErrorExt(th, "_tiffSeekProc", "%s", VSIStrerror(errno));

            return static_cast<toff_t>(-1);

        }

        psGTH->psShared->bAtEndOfFile = true;

        psGTH->psShared->nFileLength = VSIFTellL(psGTH->psShared->fpL);

        return static_cast<toff_t>(psGTH->psShared->nFileLength);

    }

    GTHFlushBuffer(th);

    psGTH->psShared->bAtEndOfFile = false;

    psGTH->psShared->nFileLength = 0;

    if (VSIFSeekL(psGTH->psShared->fpL, off, whence) == 0)

    {

        return static_cast<toff_t>(VSIFTellL(psGTH->psShared->fpL));

    }

    else

    {

        TIFFErrorExt(th, "_tiffSeekProc", "%s", VSIStrerror(errno));

        return static_cast<toff_t>(-1);

    }

}

static void FreeGTH(GDALTiffHandle *psGTH)

{

    psGTH->psShared->nUserCounter--;

    if (psGTH->psParent == nullptr)

    {

        assert(psGTH->psShared->nUserCounter == 0);

        CPLFree(psGTH->psShared->pszName);

        CPLFree(psGTH->psShared);

    }

    else

    {

        if (psGTH->psShared->psActiveHandle == psGTH)

            psGTH->psShared->psActiveHandle = nullptr;

    }

    CPLFree(psGTH->abyWriteBuffer);

    CPLFree(psGTH->ppCachedData);

    CPLFree(psGTH->panCachedOffsets);

    CPLFree(psGTH->panCachedSizes);

    CPLFree(psGTH);

}

static int _tiffCloseProc(thandle_t th)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    SetActiveGTH(psGTH);

    GTHFlushBuffer(th);

    if (psGTH->bFree)

        FreeGTH(psGTH);

    return 0;

}

static toff_t _tiffSizeProc(thandle_t th)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    SetActiveGTH(psGTH);

    if (psGTH->psShared->bAtEndOfFile)

    {

        return static_cast<toff_t>(psGTH->psShared->nFileLength);

    }

    const vsi_l_offset old_off = VSIFTellL(psGTH->psShared->fpL);

    CPL_IGNORE_RET_VAL(VSIFSeekL(psGTH->psShared->fpL, 0, SEEK_END));

    const toff_t file_size =

        static_cast<toff_t>(VSIFTellL(psGTH->psShared->fpL));

    CPL_IGNORE_RET_VAL(VSIFSeekL(psGTH->psShared->fpL, old_off, SEEK_SET));

    return file_size;

}

static int _tiffMapProc(thandle_t th, tdata_t *pbase, toff_t *psize)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    // SetActiveGTH(psGTH);

    if (psGTH->pBase)

    {

        *pbase = psGTH->pBase;

        *psize = static_cast<toff_t>(psGTH->nDataLength);

        return 1;

    }

    return 0;

}

static void _tiffUnmapProc(thandle_t /* th */, tdata_t /* base */,

                           toff_t /* size */)

{

}

VSILFILE *VSI_TIFFGetVSILFile(thandle_t th)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    SetActiveGTH(psGTH);

    VSI_TIFFFlushBufferedWrite(th);

    return psGTH->psShared->fpL;

}

int VSI_TIFFFlushBufferedWrite(thandle_t th)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    SetActiveGTH(psGTH);

    psGTH->psShared->bAtEndOfFile = false;

    return GTHFlushBuffer(th);

}

int VSI_TIFFHasCachedRanges(thandle_t th)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    return psGTH->nCachedRanges != 0;

}

toff_t VSI_TIFFSeek(TIFF *tif, toff_t off, int whence)

{

    thandle_t th = TIFFClientdata(tif);

    return _tiffSeekProc(th, off, whence);

}

int VSI_TIFFWrite(TIFF *tif, const void *buffer, size_t buffersize)

{

    thandle_t th = TIFFClientdata(tif);

    return static_cast<size_t>(_tiffWriteProc(th, const_cast<tdata_t>(buffer),

                                              buffersize)) == buffersize;

}

void VSI_TIFFSetCachedRanges(thandle_t th, int nRanges, void **ppData,

                             const vsi_l_offset *panOffsets,

                             const size_t *panSizes)

{

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    psGTH->nCachedRanges = nRanges;

    if (nRanges)

    {

        psGTH->ppCachedData = static_cast<void **>(

            CPLRealloc(psGTH->ppCachedData, nRanges * sizeof(void *)));

        memcpy(psGTH->ppCachedData, ppData, nRanges * sizeof(void *));

        psGTH->panCachedOffsets = static_cast<vsi_l_offset *>(CPLRealloc(

            psGTH->panCachedOffsets, nRanges * sizeof(vsi_l_offset)));

        memcpy(psGTH->panCachedOffsets, panOffsets,

               nRanges * sizeof(vsi_l_offset));

        psGTH->panCachedSizes = static_cast<size_t *>(

            CPLRealloc(psGTH->panCachedSizes, nRanges * sizeof(size_t)));

        memcpy(psGTH->panCachedSizes, panSizes, nRanges * sizeof(size_t));

    }

}

static bool IsReadOnly(const char *mode)

{

    bool bReadOnly = true;

    for (int i = 0; mode[i] != '\0'; i++)

    {

        if (mode[i] == 'w' || mode[i] == '+' || mode[i] == 'a')

        {

            bReadOnly = false;

        }

    }

    return bReadOnly;

}

static void InitializeWriteBuffer(GDALTiffHandle *psGTH, const char *pszMode)

{

    // No need to buffer on /vsimem/

    const bool bReadOnly = IsReadOnly(pszMode);

    bool bAllocBuffer = !bReadOnly;

    if (STARTS_WITH(psGTH->psShared->pszName, "/vsimem/"))

    {

        if (bReadOnly &&

            CPLTestBool(CPLGetConfigOption("GTIFF_USE_MMAP", "NO")))

        {

            psGTH->nDataLength = 0;

            psGTH->pBase = VSIGetMemFileBuffer(psGTH->psShared->pszName,

                                               &psGTH->nDataLength, FALSE);

        }

        bAllocBuffer = false;

    }

    psGTH->abyWriteBuffer =

        bAllocBuffer ? static_cast<GByte *>(VSIMalloc(BUFFER_SIZE)) : nullptr;

    psGTH->nWriteBufferSize = 0;

}

#ifdef SUPPORTS_LIBTIFF_OPEN_OPTIONS

static void VSI_TIFFSetOpenOptions(TIFFOpenOptions *opts)

{

    TIFFOpenOptionsSetErrorHandlerExtR(opts, GTiffErrorHandlerExt, nullptr);

    TIFFOpenOptionsSetWarningHandlerExtR(opts, GTiffWarningHandlerExt, nullptr);

#if defined(INTERNAL_LIBTIFF) || TIFFLIB_VERSION > 20230908

    // Read-once and stored in static storage otherwise affects

    // autotest/benchmark/test_gtiff.py::test_gtiff_byte

    static const GIntBig nMemLimit = []() -> GIntBig

    {

        if (const char *pszLimit =

                CPLGetConfigOption("GTIFF_MAX_CUMULATED_MEM_USAGE", nullptr))

            return CPLAtoGIntBig(pszLimit);

        else

        {

            const auto nUsableRAM = CPLGetUsablePhysicalRAM();

            if (nUsableRAM > 0)

            {

                // coverity[return_overflow]

                return nUsableRAM / 10 * 9;

            }

            else

                return 0;

        }

    }();

    if (nMemLimit > 0 && nMemLimit < std::numeric_limits<tmsize_t>::max())

    {

        //CPLDebug("GTiff", "TIFFOpenOptionsSetMaxCumulatedMemAlloc(%" PRIu64 ")",

        //         static_cast<uint64_t>(nMemLimit));

        TIFFOpenOptionsSetMaxCumulatedMemAlloc(

            opts, static_cast<tmsize_t>(nMemLimit));

    }

#endif

}

#endif

static TIFF *VSI_TIFFOpen_common(GDALTiffHandle *psGTH, const char *pszMode)

{

    InitializeWriteBuffer(psGTH, pszMode);

#ifdef SUPPORTS_LIBTIFF_OPEN_OPTIONS

    XTIFFInitialize();

    TIFFOpenOptions *opts = TIFFOpenOptionsAlloc();

    if (opts == nullptr)

    {

        FreeGTH(psGTH);

        return nullptr;

    }

    VSI_TIFFSetOpenOptions(opts);

    TIFF *tif = TIFFClientOpenExt(

        psGTH->psShared->pszName, pszMode, reinterpret_cast<thandle_t>(psGTH),

        _tiffReadProc, _tiffWriteProc, _tiffSeekProc, _tiffCloseProc,

        _tiffSizeProc, _tiffMapProc, _tiffUnmapProc, opts);

    TIFFOpenOptionsFree(opts);

#else

    TIFF *tif = XTIFFClientOpen(

        psGTH->psShared->pszName, pszMode, reinterpret_cast<thandle_t>(psGTH),

        _tiffReadProc, _tiffWriteProc, _tiffSeekProc, _tiffCloseProc,

        _tiffSizeProc, _tiffMapProc, _tiffUnmapProc);

#endif

    if (tif == nullptr)

        FreeGTH(psGTH);

    return tif;

}

// Open a TIFF file for read/writing.

TIFF *VSI_TIFFOpen(const char *name, const char *mode, VSILFILE *fpL)

{

    if (VSIFSeekL(fpL, 0, SEEK_SET) < 0)

        return nullptr;

    GDALTiffHandle *psGTH =

        static_cast<GDALTiffHandle *>(CPLCalloc(1, sizeof(GDALTiffHandle)));

    psGTH->bFree = true;

    psGTH->psParent = nullptr;

    psGTH->psShared = static_cast<GDALTiffHandleShared *>(

        CPLCalloc(1, sizeof(GDALTiffHandleShared)));

    psGTH->psShared->bReadOnly = (strchr(mode, '+') == nullptr);

    psGTH->psShared->bLazyStrileLoading = (strchr(mode, 'D') != nullptr);

    psGTH->psShared->pszName = CPLStrdup(name);

    psGTH->psShared->fpL = fpL;

    psGTH->psShared->psActiveHandle = psGTH;

    psGTH->psShared->nFileLength = 0;

    psGTH->psShared->bAtEndOfFile = false;

    psGTH->psShared->nUserCounter = 1;

    return VSI_TIFFOpen_common(psGTH, mode);

}

TIFF *VSI_TIFFOpenChild(TIFF *parent)

{

    GDALTiffHandle *psGTHParent =

        reinterpret_cast<GDALTiffHandle *>(TIFFClientdata(parent));

    GDALTiffHandle *psGTH =

        static_cast<GDALTiffHandle *>(CPLCalloc(1, sizeof(GDALTiffHandle)));

    psGTH->bFree = true;

    psGTH->psParent = psGTHParent;

    psGTH->psShared = psGTHParent->psShared;

    psGTH->psShared->nUserCounter++;

    SetActiveGTH(psGTH);

    VSIFSeekL(psGTH->psShared->fpL, 0, SEEK_SET);

    psGTH->psShared->bAtEndOfFile = false;

    const char *mode =

        psGTH->psShared->bReadOnly && psGTH->psShared->bLazyStrileLoading

            ? "rDO"

        : psGTH->psShared->bReadOnly          ? "r"

        : psGTH->psShared->bLazyStrileLoading ? "r+D"

                                              : "r+";

    return VSI_TIFFOpen_common(psGTH, mode);

}

// Re-open a TIFF handle (seeking to the appropriate directory is then needed)

TIFF *VSI_TIFFReOpen(TIFF *tif)

{

    thandle_t th = TIFFClientdata(tif);

    GDALTiffHandle *psGTH = reinterpret_cast<GDALTiffHandle *>(th);

    // Disable freeing of psGTH in _tiffCloseProc(), which could be called

    // if XTIFFClientOpen() fails, or obviously by XTIFFClose()

    psGTH->bFree = false;

    const char *mode =

        psGTH->psShared->bReadOnly && psGTH->psShared->bLazyStrileLoading

            ? "rDO"

        : psGTH->psShared->bReadOnly          ? "r"

        : psGTH->psShared->bLazyStrileLoading ? "r+D"

                                              : "r+";

    SetActiveGTH(psGTH);

    VSIFSeekL(psGTH->psShared->fpL, 0, SEEK_SET);

    psGTH->psShared->bAtEndOfFile = false;

#ifdef SUPPORTS_LIBTIFF_OPEN_OPTIONS

    TIFF *newHandle = nullptr;

    TIFFOpenOptions *opts = TIFFOpenOptionsAlloc();

    if (opts != nullptr)

    {

        VSI_TIFFSetOpenOptions(opts);

        newHandle = TIFFClientOpenExt(

            psGTH->psShared->pszName, mode, reinterpret_cast<thandle_t>(psGTH),

            _tiffReadProc, _tiffWriteProc, _tiffSeekProc, _tiffCloseProc,

            _tiffSizeProc, _tiffMapProc, _tiffUnmapProc, opts);

        TIFFOpenOptionsFree(opts);

    }

#else

    TIFF *newHandle = XTIFFClientOpen(

        psGTH->psShared->pszName, mode, reinterpret_cast<thandle_t>(psGTH),

        _tiffReadProc, _tiffWriteProc, _tiffSeekProc, _tiffCloseProc,

        _tiffSizeProc, _tiffMapProc, _tiffUnmapProc);

#endif

    if (newHandle != nullptr)

        XTIFFClose(tif);

    psGTH->bFree = true;

    return newHandle;

}