cpl_findfile.cpp

/******************************************************************************
 *
 * Project:  CPL - Common Portability Library
 * Purpose:  Generic data file location finder, with application hooking.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 2000, Frank Warmerdam
 * Copyright (c) 2009-2010, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "cpl_port.h"
#include "cpl_conv.h"

#include <cstddef>

#include "cpl_multiproc.h"
#include "cpl_string.h"
#include "cpl_vsi.h"

typedef struct
{
    bool bFinderInitialized;
    int nFileFinders;
    CPLFileFinder *papfnFinders;
    char **papszFinderLocations;
} FindFileTLS;

/************************************************************************/
/*                      CPLFindFileDeinitTLS()                          */
/************************************************************************/

static void CPLPopFinderLocationInternal(FindFileTLS *pTLSData);
static CPLFileFinder CPLPopFileFinderInternal(FindFileTLS *pTLSData);

static void CPLFindFileFreeTLS(void *pData)
{
    FindFileTLS *pTLSData = reinterpret_cast<FindFileTLS *>(pData);
    if (pTLSData != nullptr && pTLSData->bFinderInitialized)
    {
        while (pTLSData->papszFinderLocations != nullptr)
            CPLPopFinderLocationInternal(pTLSData);
        while (CPLPopFileFinderInternal(pTLSData) != nullptr)
        {
        }

        pTLSData->bFinderInitialized = false;
    }
    CPLFree(pTLSData);
}

/************************************************************************/
/*                       CPLGetFindFileTLS()                            */
/************************************************************************/

static FindFileTLS *CPLGetFindFileTLS()
{
    int bMemoryError = FALSE;
    FindFileTLS *pTLSData = reinterpret_cast<FindFileTLS *>(
        CPLGetTLSEx(CTLS_FINDFILE, &bMemoryError));
    if (bMemoryError)
        return nullptr;
    if (pTLSData == nullptr)
    {
        pTLSData = static_cast<FindFileTLS *>(
            VSI_CALLOC_VERBOSE(1, sizeof(FindFileTLS)));
        if (pTLSData == nullptr)
            return nullptr;
        CPLSetTLSWithFreeFunc(CTLS_FINDFILE, pTLSData, CPLFindFileFreeTLS);
    }
    return pTLSData;
}

/************************************************************************/
/*                           CPLFinderInit()                            */
/************************************************************************/

static FindFileTLS *CPLFinderInit()

{
    FindFileTLS *pTLSData = CPLGetFindFileTLS();
    if (pTLSData != nullptr && !pTLSData->bFinderInitialized)
    {
        pTLSData->bFinderInitialized = true;
        CPLPushFileFinder(CPLDefaultFindFile);

        CPLPushFinderLocation(".");

        if (CPLGetConfigOption("GDAL_DATA", nullptr) != nullptr)
        {
            CPLPushFinderLocation(CPLGetConfigOption("GDAL_DATA", nullptr));
        }
        else
        {
#ifdef INST_DATA
            CPLPushFinderLocation(INST_DATA);
#endif
#ifdef GDAL_PREFIX
#ifdef MACOSX_FRAMEWORK
            CPLPushFinderLocation(GDAL_PREFIX "/Resources/gdal");
#else
            CPLPushFinderLocation(GDAL_PREFIX "/share/gdal");
#endif
#endif
        }
    }
    return pTLSData;
}

/************************************************************************/
/*                           CPLFinderClean()                           */
/************************************************************************/

/** CPLFinderClean */
void CPLFinderClean()

{
    FindFileTLS *pTLSData = CPLGetFindFileTLS();
    CPLFindFileFreeTLS(pTLSData);
    int bMemoryError = FALSE;
    CPLSetTLSWithFreeFuncEx(CTLS_FINDFILE, nullptr, nullptr, &bMemoryError);
    // TODO: if( bMemoryError ) {}
}

/************************************************************************/
/*                         CPLDefaultFindFile()                         */
/************************************************************************/

/** CPLDefaultFindFile */
const char *CPLDefaultFindFile(const char *pszClass, const char *pszBasename)

{
    FindFileTLS *pTLSData = CPLGetFindFileTLS();
    if (pTLSData == nullptr)
        return nullptr;
    const int nLocations = CSLCount(pTLSData->papszFinderLocations);

    for (int i = nLocations - 1; i >= 0; i--)
    {
        const std::string osResult = CPLFormFilenameSafe(
            pTLSData->papszFinderLocations[i], pszBasename, nullptr);

        VSIStatBufL sStat;
        if (VSIStatL(osResult.c_str(), &sStat) == 0)
            return CPLSPrintf("%s", osResult.c_str());
    }

    if (EQUAL(pszClass, "gdal") && !CPLGetConfigOption("GDAL_DATA", nullptr))
    {
        CPLError(CE_Warning, CPLE_FileIO,
                 "Cannot find %s (GDAL_DATA is not defined)", pszBasename);
    }

    return nullptr;
}

/************************************************************************/
/*                            CPLFindFile()                             */
/************************************************************************/

/** CPLFindFile */
const char *CPLFindFile(const char *pszClass, const char *pszBasename)

{
    FindFileTLS *pTLSData = CPLFinderInit();
    if (pTLSData == nullptr)
        return nullptr;

    for (int i = pTLSData->nFileFinders - 1; i >= 0; i--)
    {
        const char *pszResult =
            (pTLSData->papfnFinders[i])(pszClass, pszBasename);
        if (pszResult != nullptr)
            return pszResult;
    }

    return nullptr;
}

/************************************************************************/
/*                         CPLPushFileFinder()                          */
/************************************************************************/

/** CPLPushFileFinder */
void CPLPushFileFinder(CPLFileFinder pfnFinder)

{
    FindFileTLS *pTLSData = CPLFinderInit();
    if (pTLSData == nullptr)
        return;

    pTLSData->papfnFinders = static_cast<CPLFileFinder *>(
        CPLRealloc(pTLSData->papfnFinders,
                   sizeof(CPLFileFinder) * ++pTLSData->nFileFinders));
    pTLSData->papfnFinders[pTLSData->nFileFinders - 1] = pfnFinder;
}

/************************************************************************/
/*                          CPLPopFileFinder()                          */
/************************************************************************/

CPLFileFinder CPLPopFileFinderInternal(FindFileTLS *pTLSData)

{
    if (pTLSData == nullptr)
        return nullptr;
    if (pTLSData->nFileFinders == 0)
        return nullptr;

    CPLFileFinder pfnReturn = pTLSData->papfnFinders[--pTLSData->nFileFinders];

    if (pTLSData->nFileFinders == 0)
    {
        CPLFree(pTLSData->papfnFinders);
        pTLSData->papfnFinders = nullptr;
    }

    return pfnReturn;
}

/** CPLPopFileFinder */
CPLFileFinder CPLPopFileFinder()

{
    return CPLPopFileFinderInternal(CPLFinderInit());
}

/************************************************************************/
/*                       CPLPushFinderLocation()                        */
/************************************************************************/

/** CPLPushFinderLocation */
void CPLPushFinderLocation(const char *pszLocation)

{
    FindFileTLS *pTLSData = CPLFinderInit();
    if (pTLSData == nullptr)
        return;
    // Check if location already is in list.
    if (CSLFindStringCaseSensitive(pTLSData->papszFinderLocations,
                                   pszLocation) > -1)
        return;
    pTLSData->papszFinderLocations =
        CSLAddStringMayFail(pTLSData->papszFinderLocations, pszLocation);
}

/************************************************************************/
/*                       CPLPopFinderLocation()                         */
/************************************************************************/

static void CPLPopFinderLocationInternal(FindFileTLS *pTLSData)

{
    if (pTLSData == nullptr || pTLSData->papszFinderLocations == nullptr)
        return;

    const int nCount = CSLCount(pTLSData->papszFinderLocations);
    if (nCount == 0)
        return;

    CPLFree(pTLSData->papszFinderLocations[nCount - 1]);
    pTLSData->papszFinderLocations[nCount - 1] = nullptr;

    if (nCount == 1)
    {
        CPLFree(pTLSData->papszFinderLocations);
        pTLSData->papszFinderLocations = nullptr;
    }
}

/** CPLPopFinderLocation */
void CPLPopFinderLocation()
{
    CPLPopFinderLocationInternal(CPLFinderInit());
}