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

 *

 * Project:  OpenGIS Simple Features Reference Implementation

 * Purpose:  Implements OGRVRTDriver class.

 * Author:   Frank Warmerdam, warmerdam@pobox.com

 *

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

 * Copyright (c) 2003, Frank Warmerdam <warmerdam@pobox.com>

 * Copyright (c) 2009-2014, Even Rouault <even dot rouault at spatialys.com>

 *

 * SPDX-License-Identifier: MIT

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

#include "cpl_port.h"

#include "ogr_vrt.h"

#include <cctype>

#include <cstddef>

#include <cstdio>

#include <cstring>

#include <limits>

#include <memory>

#include <vector>

#include "cpl_conv.h"

#include "cpl_error.h"

#include "cpl_minixml.h"

#include "cpl_string.h"

#include "cpl_vsi.h"

#include "gdal.h"

#include "gdal_priv.h"

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

/*                           OGRVRTErrorHandler()                       */

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

static void CPL_STDCALL OGRVRTErrorHandler(CPL_UNUSED CPLErr eErr,

                                           CPL_UNUSED CPLErrorNum nType,

                                           const char *pszMsg)

{

    std::vector<CPLString> *paosErrors =

        static_cast<std::vector<CPLString> *>(CPLGetErrorHandlerUserData());

    paosErrors->push_back(pszMsg);

}

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

/*                         OGRVRTDriverIdentify()                       */

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

static int OGRVRTDriverIdentify(GDALOpenInfo *poOpenInfo)

{

    if (!poOpenInfo->bStatOK)

    {

        // Are we being passed the XML definition directly?

        // Skip any leading spaces/blanks.

        const char *pszTestXML = poOpenInfo->pszFilename;

        while (*pszTestXML != '\0' &&

               isspace(static_cast<unsigned char>(*pszTestXML)))

            pszTestXML++;

        if (STARTS_WITH_CI(pszTestXML, "<OGRVRTDataSource>"))

        {

            return TRUE;

        }

        return FALSE;

    }

    return poOpenInfo->fpL != nullptr &&

           strstr(reinterpret_cast<char *>(poOpenInfo->pabyHeader),

                  "<OGRVRTDataSource") != nullptr;

}

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

/*                                Open()                                */

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

static GDALDataset *OGRVRTDriverOpen(GDALOpenInfo *poOpenInfo)

{

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

    if (!OGRVRTDriverIdentify(poOpenInfo))

        return nullptr;

#endif

    // Are we being passed the XML definition directly?

    // Skip any leading spaces/blanks.

    const char *pszTestXML = poOpenInfo->pszFilename;

    while (*pszTestXML != '\0' &&

           isspace(static_cast<unsigned char>(*pszTestXML)))

        pszTestXML++;

    char *pszXML = nullptr;

    if (STARTS_WITH_CI(pszTestXML, "<OGRVRTDataSource>"))

    {

        pszXML = CPLStrdup(pszTestXML);

    }

    // Open file and check if it contains appropriate XML.

    else

    {

#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

        if (poOpenInfo->fpL == nullptr)

            return nullptr;

#endif

        VSIStatBufL sStatBuf;

        if (VSIStatL(poOpenInfo->pszFilename, &sStatBuf) != 0)

        {

            return nullptr;

        }

        if (sStatBuf.st_size > 10 * 1024 * 1024 &&

            !CPLTestBool(CPLGetConfigOption("OGR_VRT_FORCE_LOADING", "NO")))

        {

            CPLError(CE_Failure, CPLE_AppDefined,

                     "Suscipicously long VRT file. If you really want to "

                     "open it, define OGR_VRT_FORCE_LOADING=YES as "

                     "configuration option");

            return nullptr;

        }

        if (static_cast<uint64_t>(sStatBuf.st_size) >

            std::numeric_limits<size_t>::max() - 1)

        {

            return nullptr;

        }

        // It is the right file, now load the full XML definition.

        const size_t nLen = static_cast<size_t>(sStatBuf.st_size);

        pszXML = static_cast<char *>(VSI_MALLOC_VERBOSE(nLen + 1));

        if (pszXML == nullptr)

            return nullptr;

        pszXML[nLen] = '\0';

        VSIFSeekL(poOpenInfo->fpL, 0, SEEK_SET);

        if (VSIFReadL(pszXML, 1, nLen, poOpenInfo->fpL) != nLen)

        {

            CPLFree(pszXML);

            return nullptr;

        }

        VSIFCloseL(poOpenInfo->fpL);

        poOpenInfo->fpL = nullptr;

    }

    // Parse the XML.

    CPLXMLNode *psTree = CPLParseXMLString(pszXML);

    if (psTree == nullptr)

    {

        CPLFree(pszXML);

        return nullptr;

    }

    // XML Validation.

    if (CPLTestBool(CPLGetConfigOption("GDAL_XML_VALIDATION", "YES")))

    {

        const char *pszXSD = CPLFindFile("gdal", "ogrvrt.xsd");

        if (pszXSD != nullptr)

        {

            std::vector<CPLString> aosErrors;

            CPLPushErrorHandlerEx(OGRVRTErrorHandler, &aosErrors);

            const int bRet = CPLValidateXML(pszXML, pszXSD, nullptr);

            CPLPopErrorHandler();

            if (!bRet)

            {

                if (!aosErrors.empty() &&

                    strstr(aosErrors[0].c_str(), "missing libxml2 support") ==

                        nullptr)

                {

                    for (size_t i = 0; i < aosErrors.size(); i++)

                    {

                        CPLError(CE_Warning, CPLE_AppDefined, "%s",

                                 aosErrors[i].c_str());

                    }

                }

            }

            CPLErrorReset();

        }

    }

    CPLFree(pszXML);

    // Create a virtual datasource configured based on this XML input.

    OGRVRTDataSource *poDS = new OGRVRTDataSource(

        static_cast<GDALDriver *>(GDALGetDriverByName("OGR_VRT")));

    // psTree is owned by poDS.

    if (!poDS->Initialize(psTree, poOpenInfo->pszFilename,

                          poOpenInfo->eAccess == GA_Update))

    {

        delete poDS;

        return nullptr;

    }

    return poDS;

}

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

/*                           RegisterOGRVRT()                           */

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

void RegisterOGRVRT()

{

    if (GDALGetDriverByName("OGR_VRT") != nullptr)

        return;

    GDALDriver *poDriver = new GDALDriver();

    poDriver->SetDescription("OGR_VRT");

    poDriver->SetMetadataItem(GDAL_DCAP_VECTOR, "YES");

    poDriver->SetMetadataItem(GDAL_DMD_LONGNAME, "VRT - Virtual Datasource");

    poDriver->SetMetadataItem(GDAL_DMD_EXTENSION, "vrt");

    poDriver->SetMetadataItem(GDAL_DMD_HELPTOPIC, "drivers/vector/vrt.html");

    poDriver->SetMetadataItem(GDAL_DCAP_VIRTUALIO, "YES");

    poDriver->SetMetadataItem(GDAL_DCAP_FEATURE_STYLES, "YES");

    poDriver->SetMetadataItem(GDAL_DCAP_FEATURE_STYLES_READ, "YES");

    poDriver->SetMetadataItem(GDAL_DCAP_MULTIPLE_VECTOR_LAYERS, "YES");

    poDriver->SetMetadataItem(GDAL_DCAP_CURVE_GEOMETRIES, "YES");

    poDriver->SetMetadataItem(GDAL_DCAP_MEASURED_GEOMETRIES, "YES");

    poDriver->SetMetadataItem(GDAL_DCAP_Z_GEOMETRIES, "YES");

    poDriver->SetMetadataItem(GDAL_DMD_SUPPORTED_SQL_DIALECTS, "OGRSQL SQLITE");

    poDriver->SetMetadataItem(GDAL_DMD_CREATION_FIELD_DEFN_FLAGS,

                              "WidthPrecision Nullable Unique Default "

                              "Comment AlternativeName");

    poDriver->pfnOpen = OGRVRTDriverOpen;

    poDriver->pfnIdentify = OGRVRTDriverIdentify;

    GetGDALDriverManager()->RegisterDriver(poDriver);

}