/******************************************************************************
 *
 * Project:  CPL - Common Portability Library
 * Purpose:  Implement VSI large file api for Microsoft Azure Blob Storage
 * Author:   Even Rouault, even.rouault at spatialys.com
 *
 ******************************************************************************
 * Copyright (c) 2017-2018, Even Rouault <even.rouault at spatialys.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "cpl_port.h"
#include "cpl_http.h"
#include "cpl_minixml.h"
#include "cpl_time.h"
#include "cpl_vsil_curl_priv.h"
#include "cpl_vsil_curl_class.h"

#include <errno.h>

#include <algorithm>
#include <set>
#include <map>
#include <memory>

#include "cpl_azure.h"


// #define DEBUG_VERBOSE 1

#ifndef HAVE_CURL

void VSIInstallAzureFileHandler( void )
{
    // Not supported
}

#else

//! @cond Doxygen_Suppress
#ifndef DOXYGEN_SKIP

#define ENABLE_DEBUG 0

#define unchecked_curl_easy_setopt(handle,opt,param) CPL_IGNORE_RET_VAL(curl_easy_setopt(handle,opt,param))

namespace cpl {

const char GDAL_MARKER_FOR_DIR[] = ".gdal_marker_for_dir";

/************************************************************************/
/*                             VSIDIRAz                                 */
/************************************************************************/

struct VSIDIRAz: public VSIDIRWithMissingDirSynthesis
{
    CPLString osRootPath{};
    int nRecurseDepth = 0;

    CPLString osNextMarker{};
    int nPos = 0;

    CPLString osBucket{};
    CPLString osObjectKey{};
    IVSIS3LikeFSHandler* poFS = nullptr;
    std::unique_ptr<IVSIS3LikeHandleHelper> poHandleHelper{};
    int nMaxFiles = 0;
    bool bCacheEntries = true;
    bool m_bSynthetizeMissingDirectories = false;
    std::string m_osFilterPrefix{};

    explicit VSIDIRAz(IVSIS3LikeFSHandler *poFSIn): poFS(poFSIn) {}

    VSIDIRAz(const VSIDIRAz&) = delete;
    VSIDIRAz& operator=(const VSIDIRAz&) = delete;

    const VSIDIREntry* NextDirEntry() override;

    bool IssueListDir();
    bool AnalyseAzureFileList( const CPLString& osBaseURL,
                               const char* pszXML );
    void clear();
};

/************************************************************************/
/*                                clear()                               */
/************************************************************************/

void VSIDIRAz::clear()
{
    osNextMarker.clear();
    nPos = 0;
    aoEntries.clear();
}

/************************************************************************/
/*                        AnalyseAzureFileList()                        */
/************************************************************************/

bool VSIDIRAz::AnalyseAzureFileList(
    const CPLString& osBaseURL,
    const char* pszXML)
{
#if DEBUG_VERBOSE
    CPLDebug("AZURE", "%s", pszXML);
#endif

    CPLXMLNode* psTree = CPLParseXMLString(pszXML);
    if( psTree == nullptr )
        return false;
    CPLXMLNode* psEnumerationResults = CPLGetXMLNode(psTree, "=EnumerationResults");

    bool bNonEmpty = false;
    if( psEnumerationResults )
    {
        CPLString osPrefix = CPLGetXMLValue(psEnumerationResults, "Prefix", "");
        if( osPrefix.empty() )
        {
            // in the case of an empty bucket
            bNonEmpty = true;
        }
        else if( osPrefix.endsWith(m_osFilterPrefix) )
        {
            osPrefix.resize(osPrefix.size() - m_osFilterPrefix.size());
        }

        CPLXMLNode* psBlobs = CPLGetXMLNode(psEnumerationResults, "Blobs");
        if( psBlobs == nullptr )
        {
            psBlobs = CPLGetXMLNode(psEnumerationResults, "Containers");
            if( psBlobs != nullptr )
                bNonEmpty = true;
        }

        // Count the number of occurrences of a path. Can be 1 or 2. 2 in the case
        // that both a filename and directory exist
        std::map<CPLString, int> aoNameCount;
        for(CPLXMLNode* psIter = psBlobs ? psBlobs->psChild : nullptr;
            psIter != nullptr; psIter = psIter->psNext )
        {
            if( psIter->eType != CXT_Element )
                continue;
            if( strcmp(psIter->pszValue, "Blob") == 0 )
            {
                const char* pszKey = CPLGetXMLValue(psIter, "Name", nullptr);
                if( pszKey && strstr(pszKey, GDAL_MARKER_FOR_DIR) != nullptr )
                {
                    bNonEmpty = true;
                }
                else if( pszKey && strlen(pszKey) > osPrefix.size() )
                {
                    bNonEmpty = true;
                    aoNameCount[pszKey + osPrefix.size()] ++;
                }
            }
            else if( strcmp(psIter->pszValue, "BlobPrefix") == 0 ||
                     strcmp(psIter->pszValue, "Container") == 0 )
            {
                bNonEmpty = true;

                const char* pszKey = CPLGetXMLValue(psIter, "Name", nullptr);
                if( pszKey && strncmp(pszKey, osPrefix, osPrefix.size()) == 0 )
                {
                    CPLString osKey = pszKey;
                    if( !osKey.empty() && osKey.back() == '/' )
                        osKey.resize(osKey.size()-1);
                    if( osKey.size() > osPrefix.size() )
                    {
                        aoNameCount[osKey.c_str() + osPrefix.size()] ++;
                    }
                }
            }
        }

        for(CPLXMLNode* psIter = psBlobs ? psBlobs->psChild : nullptr;
            psIter != nullptr; psIter = psIter->psNext )
        {
            if( psIter->eType != CXT_Element )
                continue;
            if( strcmp(psIter->pszValue, "Blob") == 0 )
            {
                const char* pszKey = CPLGetXMLValue(psIter, "Name", nullptr);
                if( pszKey && strstr(pszKey, GDAL_MARKER_FOR_DIR) != nullptr )
                {
                    if( nRecurseDepth < 0 )
                    {
                        aoEntries.push_back(
                            std::unique_ptr<VSIDIREntry>(new VSIDIREntry()));
                        auto& entry = aoEntries.back();
                        entry->pszName = CPLStrdup(pszKey + osPrefix.size());
                        char* pszMarker = strstr(entry->pszName, GDAL_MARKER_FOR_DIR);
                        if( pszMarker )
                            *pszMarker = '\0';
                        entry->nMode = S_IFDIR;
                        entry->bModeKnown = true;
                    }
                }
                else if( pszKey && strlen(pszKey) > osPrefix.size() )
                {
                    const std::string osKeySuffix = pszKey + osPrefix.size();
                    if( m_bSynthetizeMissingDirectories)
                    {
                        const auto nLastSlashPos = osKeySuffix.rfind('/');
                        if( nLastSlashPos != std::string::npos &&
                            (m_aosSubpathsStack.empty() ||
                             osKeySuffix.compare(0, nLastSlashPos, m_aosSubpathsStack.back()) != 0) )
                        {
                            const bool bAddEntryForThisSubdir =
                                nLastSlashPos != osKeySuffix.size() - 1;
                            SynthetizeMissingDirectories(osKeySuffix.substr(0, nLastSlashPos),
                                                         bAddEntryForThisSubdir);
                        }
                    }

                    aoEntries.push_back(
                        std::unique_ptr<VSIDIREntry>(new VSIDIREntry()));
                    auto& entry = aoEntries.back();
                    entry->pszName = CPLStrdup(osKeySuffix.c_str());
                    entry->nSize = static_cast<GUIntBig>(
                        CPLAtoGIntBig(CPLGetXMLValue(psIter, "Properties.Content-Length", "0")));
                    entry->bSizeKnown = true;
                    entry->nMode = S_IFREG;
                    entry->bModeKnown = true;

                    CPLString ETag = CPLGetXMLValue(psIter, "Etag", "");
                    if( !ETag.empty() )
                    {
                        entry->papszExtra = CSLSetNameValue(
                            entry->papszExtra, "ETag", ETag.c_str());
                    }

                    int nYear, nMonth, nDay, nHour, nMinute, nSecond;
                    if( CPLParseRFC822DateTime(
                        CPLGetXMLValue(psIter, "Properties.Last-Modified", ""),
                                                    &nYear,
                                                    &nMonth,
                                                    &nDay,
                                                    &nHour,
                                                    &nMinute,
                                                    &nSecond,
                                                    nullptr,
                                                    nullptr ) )
                    {
                        struct tm brokendowntime;
                        brokendowntime.tm_year = nYear - 1900;
                        brokendowntime.tm_mon = nMonth - 1;
                        brokendowntime.tm_mday = nDay;
                        brokendowntime.tm_hour = nHour;
                        brokendowntime.tm_min = nMinute;
                        brokendowntime.tm_sec = nSecond < 0 ? 0 : nSecond;
                        entry->nMTime =
                                CPLYMDHMSToUnixTime(&brokendowntime);
                        entry->bMTimeKnown = true;
                    }

                    if( bCacheEntries )
                    {
                        FileProp prop;
                        prop.eExists = EXIST_YES;
                        prop.bHasComputedFileSize = true;
                        prop.fileSize = entry->nSize;
                        prop.bIsDirectory = false;
                        prop.mTime = static_cast<time_t>(entry->nMTime);
                        prop.ETag = ETag;
                        prop.nMode = entry->nMode;

                        CPLString osCachedFilename =
                            osBaseURL + "/" + CPLAWSURLEncode(osPrefix, false) +
                            CPLAWSURLEncode(entry->pszName, false);
#if DEBUG_VERBOSE
                        CPLDebug("AZURE", "Cache %s", osCachedFilename.c_str());
#endif
                        poFS->SetCachedFileProp(osCachedFilename, prop);
                    }
                }
            }
            else if( strcmp(psIter->pszValue, "BlobPrefix") == 0 ||
                     strcmp(psIter->pszValue, "Container") == 0 )
            {
                const char* pszKey = CPLGetXMLValue(psIter, "Name", nullptr);
                if( pszKey && strncmp(pszKey, osPrefix, osPrefix.size()) == 0 )
                {
                    CPLString osKey = pszKey;
                    if( !osKey.empty() && osKey.back() == '/' )
                        osKey.resize(osKey.size()-1);
                    if( osKey.size() > osPrefix.size() )
                    {
                        aoEntries.push_back(
                            std::unique_ptr<VSIDIREntry>(new VSIDIREntry()));
                        auto& entry = aoEntries.back();
                        entry->pszName = CPLStrdup(osKey.c_str() + osPrefix.size());
                        if( aoNameCount[entry->pszName] == 2 )
                        {
                            // Add a / suffix to disambiguish the situation
                            // Normally we don't suffix directories with /, but
                            // we have no alternative here
                            CPLString osTemp(entry->pszName);
                            osTemp += '/';
                            CPLFree(entry->pszName);
                            entry->pszName = CPLStrdup(osTemp);
                        }
                        entry->nMode = S_IFDIR;
                        entry->bModeKnown = true;

                        if( bCacheEntries )
                        {
                            FileProp prop;
                            prop.eExists = EXIST_YES;
                            prop.bIsDirectory = true;
                            prop.bHasComputedFileSize = true;
                            prop.fileSize = 0;
                            prop.mTime = 0;
                            prop.nMode = entry->nMode;

                            CPLString osCachedFilename =
                                osBaseURL + "/" + CPLAWSURLEncode(osPrefix, false) +
                                CPLAWSURLEncode(entry->pszName, false);
#if DEBUG_VERBOSE
                            CPLDebug("AZURE", "Cache %s", osCachedFilename.c_str());
#endif
                            poFS->SetCachedFileProp(osCachedFilename, prop);
                        }
                    }
                }
            }

            if( nMaxFiles > 0 && aoEntries.size() > static_cast<unsigned>(nMaxFiles) )
                break;
        }

        osNextMarker = CPLGetXMLValue(psEnumerationResults, "NextMarker", "");
    }
    CPLDestroyXMLNode(psTree);

    return bNonEmpty;
}

/************************************************************************/
/*                          IssueListDir()                              */
/************************************************************************/

bool VSIDIRAz::IssueListDir()
{
    WriteFuncStruct sWriteFuncData;
    const CPLString l_osNextMarker(osNextMarker);
    clear();

    NetworkStatisticsFileSystem oContextFS("/vsiaz/");
    NetworkStatisticsAction oContextAction("ListBucket");

    CPLString osMaxKeys = CPLGetConfigOption("AZURE_MAX_RESULTS", "");
    const int AZURE_SERVER_LIMIT_SINGLE_REQUEST = 5000;
    if( nMaxFiles > 0 && nMaxFiles < AZURE_SERVER_LIMIT_SINGLE_REQUEST &&
        (osMaxKeys.empty() || nMaxFiles < atoi(osMaxKeys)) )
    {
        osMaxKeys.Printf("%d", nMaxFiles);
    }

    poHandleHelper->ResetQueryParameters();
    const CPLString osBaseURL(poHandleHelper->GetURLNoKVP());

    CURL* hCurlHandle = curl_easy_init();

    poHandleHelper->AddQueryParameter("comp", "list");
    if( !l_osNextMarker.empty() )
        poHandleHelper->AddQueryParameter("marker", l_osNextMarker);
    if( !osMaxKeys.empty() )
            poHandleHelper->AddQueryParameter("maxresults", osMaxKeys);

    if( !osBucket.empty() )
    {
        poHandleHelper->AddQueryParameter("restype", "container");

        if( nRecurseDepth == 0 )
            poHandleHelper->AddQueryParameter("delimiter", "/");
        if( !osObjectKey.empty() )
            poHandleHelper->AddQueryParameter("prefix", osObjectKey + "/" + m_osFilterPrefix);
        else if( !m_osFilterPrefix.empty() )
            poHandleHelper->AddQueryParameter("prefix", m_osFilterPrefix);
    }

    struct curl_slist* headers =
        VSICurlSetOptions(hCurlHandle, poHandleHelper->GetURL(), nullptr);

    headers = VSICurlMergeHeaders(headers,
                            poHandleHelper->GetCurlHeaders("GET", headers));
    unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_HTTPHEADER, headers);

    CurlRequestHelper requestHelper;
    const long response_code =
        requestHelper.perform(hCurlHandle, headers, poFS, poHandleHelper.get());

    NetworkStatisticsLogger::LogGET(sWriteFuncData.nSize);

    if( requestHelper.sWriteFuncData.pBuffer == nullptr)
    {
        curl_easy_cleanup(hCurlHandle);
        return false;
    }

    bool ret = false;
    if( response_code != 200 )
    {
        CPLDebug("AZURE", "%s",
                    requestHelper.sWriteFuncData.pBuffer
                    ? requestHelper.sWriteFuncData.pBuffer : "(null)");
    }
    else
    {
        ret = AnalyseAzureFileList( osBaseURL,
                                    requestHelper.sWriteFuncData.pBuffer );
    }
    curl_easy_cleanup(hCurlHandle);
    return ret;
}

/************************************************************************/
/*                           NextDirEntry()                             */
/************************************************************************/

const VSIDIREntry* VSIDIRAz::NextDirEntry()
{
    while( true )
    {
        if( nPos < static_cast<int>(aoEntries.size()) )
        {
            auto& entry = aoEntries[nPos];
            nPos ++;
            return entry.get();
        }
        if( osNextMarker.empty() )
        {
            return nullptr;
        }
        if( !IssueListDir() )
        {
            return nullptr;
        }
    }
}

/************************************************************************/
/*                       VSIAzureFSHandler                              */
/************************************************************************/

class VSIAzureFSHandler final : public IVSIS3LikeFSHandler
{
    CPL_DISALLOW_COPY_ASSIGN(VSIAzureFSHandler)

    int CreateContainer( const std::string& osDirname );
    int DeleteContainer( const std::string& osDirname );

  protected:
    VSICurlHandle* CreateFileHandle( const char* pszFilename ) override;
    CPLString GetURLFromFilename( const CPLString& osFilename ) override;

    IVSIS3LikeHandleHelper* CreateHandleHelper(
        const char* pszURI, bool bAllowNoObject) override;

    char** GetFileList( const char *pszFilename,
                        int nMaxFiles,
                        bool* pbGotFileList ) override;

    void InvalidateRecursive( const CPLString& osDirnameIn );

    int      CopyObject( const char *oldpath, const char *newpath,
                         CSLConstList papszMetadata ) override;
    int MkdirInternal( const char *pszDirname, long nMode, bool bDoStatCheck ) override;

    void ClearCache() override;

    bool IsAllowedHeaderForObjectCreation( const char* pszHeaderName ) override { return STARTS_WITH(pszHeaderName, "x-ms-"); }

  public:
    VSIAzureFSHandler() = default;
    ~VSIAzureFSHandler() override = default;

    CPLString GetFSPrefix() const override { return "/vsiaz/"; }
    const char* GetDebugKey() const override { return "AZURE"; }

    VSIVirtualHandle *Open( const char *pszFilename,
                            const char *pszAccess,
                            bool bSetError,
                            CSLConstList papszOptions ) override;

    int Unlink( const char *pszFilename ) override;
    int Mkdir( const char *, long  ) override;
    int Rmdir( const char * ) override;
    int Stat( const char *pszFilename, VSIStatBufL *pStatBuf,
              int nFlags ) override;

    char** GetFileMetadata( const char * pszFilename, const char* pszDomain,
                            CSLConstList papszOptions ) override;

    bool   SetFileMetadata( const char * pszFilename,
                            CSLConstList papszMetadata,
                            const char* pszDomain,
                            CSLConstList papszOptions ) override;

    const char* GetOptions() override;

    char* GetSignedURL( const char* pszFilename, CSLConstList papszOptions ) override;

    char** GetFileList( const char *pszFilename,
                        int nMaxFiles,
                        bool bCacheEntries,
                        bool* pbGotFileList );

    VSIDIR* OpenDir( const char *pszPath, int nRecurseDepth,
                            const char* const *papszOptions) override;

    // Block list upload
    CPLString PutBlock(const CPLString& osFilename,
                       int nPartNumber,
                       const void* pabyBuffer,
                       size_t nBufferSize,
                       IVSIS3LikeHandleHelper *poS3HandleHelper,
                       int nMaxRetry,
                       double dfRetryDelay,
                       CSLConstList papszOptions);
    bool PutBlockList(const CPLString& osFilename,
                      const std::vector<CPLString>& aosBlockIds,
                      IVSIS3LikeHandleHelper *poS3HandleHelper,
                      int nMaxRetry,
                      double dfRetryDelay);

    // Multipart upload (mapping of S3 interface to PutBlock/PutBlockList)

    bool SupportsParallelMultipartUpload() const override { return true; }

    bool SupportsSequentialWrite( const char* /* pszPath */, bool /* bAllowLocalTempFile */ ) override { return true; }
    bool SupportsRandomWrite( const char* /* pszPath */, bool /* bAllowLocalTempFile */ ) override;

    CPLString InitiateMultipartUpload(
                                const std::string& /* osFilename */ ,
                                IVSIS3LikeHandleHelper *,
                                int /* nMaxRetry */,
                                double /* dfRetryDelay */,
                                CSLConstList /* papszOptions */) override { return "dummy"; }

    CPLString UploadPart(const CPLString& osFilename,
                         int nPartNumber,
                         const std::string& /* osUploadID */,
                         vsi_l_offset /* nPosition */,
                         const void* pabyBuffer,
                         size_t nBufferSize,
                         IVSIS3LikeHandleHelper *poS3HandleHelper,
                         int nMaxRetry,
                         double dfRetryDelay,
                         CSLConstList papszOptions) override
    {
        return PutBlock(osFilename, nPartNumber, pabyBuffer, nBufferSize,
                        poS3HandleHelper, nMaxRetry, dfRetryDelay, papszOptions);
    }

    bool CompleteMultipart(const CPLString& osFilename,
                           const CPLString& /* osUploadID */,
                           const std::vector<CPLString>& aosEtags,
                           vsi_l_offset /* nTotalSize */,
                           IVSIS3LikeHandleHelper *poS3HandleHelper,
                           int nMaxRetry,
                           double dfRetryDelay) override
    {
        return PutBlockList(osFilename, aosEtags,
                            poS3HandleHelper, nMaxRetry, dfRetryDelay);
    }

    bool AbortMultipart(const CPLString& /* osFilename */,
                        const CPLString& /* osUploadID */,
                        IVSIS3LikeHandleHelper * /*poS3HandleHelper */,
                        int /* nMaxRetry */,
                        double /* dfRetryDelay */) override { return true; }

    std::string GetStreamingFilename(const std::string& osFilename) const override;
};

/************************************************************************/
/*                          VSIAzureHandle                              */
/************************************************************************/

class VSIAzureHandle final : public VSICurlHandle
{
    CPL_DISALLOW_COPY_ASSIGN(VSIAzureHandle)

    std::unique_ptr<VSIAzureBlobHandleHelper> m_poHandleHelper{};

  protected:
        virtual struct curl_slist* GetCurlHeaders( const CPLString& osVerb,
                    const struct curl_slist* psExistingHeaders ) override;
        virtual bool IsDirectoryFromExists( const char* pszVerb,
                                            int response_code ) override;

    public:
        VSIAzureHandle( VSIAzureFSHandler* poFS, const char* pszFilename,
                     VSIAzureBlobHandleHelper* poHandleHelper);
};

/************************************************************************/
/*                          CreateFileHandle()                          */
/************************************************************************/

VSICurlHandle* VSIAzureFSHandler::CreateFileHandle(const char* pszFilename)
{
    VSIAzureBlobHandleHelper* poHandleHelper =
        VSIAzureBlobHandleHelper::BuildFromURI( pszFilename + GetFSPrefix().size(),
                                         GetFSPrefix() );
    if( poHandleHelper == nullptr )
        return nullptr;
    return new VSIAzureHandle(this, pszFilename, poHandleHelper);
}

/************************************************************************/
/*                                Stat()                                */
/************************************************************************/

int VSIAzureFSHandler::Stat( const char *pszFilename, VSIStatBufL *pStatBuf,
                          int nFlags )
{
    if( !STARTS_WITH_CI(pszFilename, GetFSPrefix()) )
        return -1;

    if( (nFlags & VSI_STAT_CACHE_ONLY) != 0 )
        return VSICurlFilesystemHandlerBase::Stat(pszFilename, pStatBuf, nFlags);

    CPLString osFilename(pszFilename);

    if( (osFilename.find('/', GetFSPrefix().size()) == std::string::npos ||
         osFilename.find('/', GetFSPrefix().size()) == osFilename.size() - 1) &&
        CPLGetConfigOption("AZURE_SAS", nullptr) != nullptr )
    {
        // On "/vsiaz/container", a HEAD or GET request fails to authenticate
        // when SAS is used, so use directory listing instead.
        char** papszRet = ReadDirInternal( osFilename, 100, nullptr );
        int nRet = papszRet ? 0 : -1;
        if( nRet == 0 )
        {
            pStatBuf->st_mtime = 0;
            pStatBuf->st_size = 0;
            pStatBuf->st_mode = S_IFDIR;

            FileProp cachedFileProp;
            GetCachedFileProp(GetURLFromFilename(osFilename), cachedFileProp);
            cachedFileProp.eExists = EXIST_YES;
            cachedFileProp.bIsDirectory = true;
            cachedFileProp.bHasComputedFileSize = true;
            SetCachedFileProp(GetURLFromFilename(osFilename), cachedFileProp);
        }
        CSLDestroy(papszRet);
        return nRet;
    }

    if( osFilename.find('/', GetFSPrefix().size()) == std::string::npos )
    {
        osFilename += "/";
    }

    if( osFilename.size() > GetFSPrefix().size() )
    {
        // Special case for container
        CPLString osFilenameWithoutEndSlash(osFilename);
        if( osFilenameWithoutEndSlash.back() == '/' )
            osFilenameWithoutEndSlash.resize( osFilenameWithoutEndSlash.size() - 1 );
        if( osFilenameWithoutEndSlash.find('/', GetFSPrefix().size()) == std::string::npos )
        {
            char** papszFileList = ReadDir(GetFSPrefix());
            const int nIdx = CSLFindString(papszFileList, osFilenameWithoutEndSlash.substr(GetFSPrefix().size()).c_str());
            CSLDestroy(papszFileList);
            if( nIdx >= 0 )
            {
                pStatBuf->st_mtime = 0;
                pStatBuf->st_size = 0;
                pStatBuf->st_mode = S_IFDIR;
                return 0;
            }
        }
    }

    return VSICurlFilesystemHandlerBase::Stat(osFilename, pStatBuf, nFlags);
}


/************************************************************************/
/*                          GetFileMetadata()                           */
/************************************************************************/

char** VSIAzureFSHandler::GetFileMetadata( const char* pszFilename,
                                        const char* pszDomain,
                                        CSLConstList papszOptions )
{
    if( !STARTS_WITH_CI(pszFilename, GetFSPrefix()) )
        return nullptr;

    if( pszDomain == nullptr ||
        (!EQUAL(pszDomain, "TAGS") && !EQUAL(pszDomain, "METADATA")) )
    {
        return VSICurlFilesystemHandlerBase::GetFileMetadata(
                    pszFilename, pszDomain, papszOptions);
    }

    auto poHandleHelper = std::unique_ptr<IVSIS3LikeHandleHelper>(
        CreateHandleHelper(pszFilename + GetFSPrefix().size(), false));
    if( poHandleHelper == nullptr )
    {
        return nullptr;
    }

    NetworkStatisticsFileSystem oContextFS(GetFSPrefix());
    NetworkStatisticsAction oContextAction("GetFileMetadata");

    bool bRetry;
    // coverity[tainted_data]
    double dfRetryDelay = CPLAtof(CPLGetConfigOption("GDAL_HTTP_RETRY_DELAY",
                                CPLSPrintf("%f", CPL_HTTP_RETRY_DELAY)));
    const int nMaxRetry = atoi(CPLGetConfigOption("GDAL_HTTP_MAX_RETRY",
                                   CPLSPrintf("%d",CPL_HTTP_MAX_RETRY)));
    int nRetryCount = 0;
    bool bError = true;

    CPLStringList aosMetadata;
    do
    {
        bRetry = false;
        CURL* hCurlHandle = curl_easy_init();
        if( EQUAL(pszDomain, "METADATA") )
            poHandleHelper->AddQueryParameter("comp", "metadata");
        else
            poHandleHelper->AddQueryParameter("comp", "tags");

        struct curl_slist* headers =
            VSICurlSetOptions(hCurlHandle, poHandleHelper->GetURL(), nullptr);

        headers = VSICurlMergeHeaders(headers,
                                poHandleHelper->GetCurlHeaders("GET", headers));
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_HTTPHEADER, headers);

        CurlRequestHelper requestHelper;
        const long response_code =
            requestHelper.perform(hCurlHandle, headers, this, poHandleHelper.get());

        NetworkStatisticsLogger::LogGET(requestHelper.sWriteFuncData.nSize);

        if( response_code != 200 || requestHelper.sWriteFuncHeaderData.pBuffer == nullptr )
        {
            // Look if we should attempt a retry
            const double dfNewRetryDelay = CPLHTTPGetNewRetryDelay(
                static_cast<int>(response_code), dfRetryDelay,
                requestHelper.sWriteFuncHeaderData.pBuffer, requestHelper.szCurlErrBuf);
            if( dfNewRetryDelay > 0 &&
                nRetryCount < nMaxRetry )
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                            "HTTP error code: %d - %s. "
                            "Retrying again in %.1f secs",
                            static_cast<int>(response_code),
                            poHandleHelper->GetURL().c_str(),
                            dfRetryDelay);
                CPLSleep(dfRetryDelay);
                dfRetryDelay = dfNewRetryDelay;
                nRetryCount++;
                bRetry = true;
            }
            else
            {
                CPLDebug(GetDebugKey(), "GetFileMetadata failed on %s: %s",
                         pszFilename,
                         requestHelper.sWriteFuncData.pBuffer
                         ? requestHelper.sWriteFuncData.pBuffer
                         : "(null)");
            }
        }
        else
        {
            if( EQUAL(pszDomain, "METADATA") )
            {
                char** papszHeaders = CSLTokenizeString2(requestHelper.sWriteFuncHeaderData.pBuffer, "\r\n", 0);
                for( int i = 0; papszHeaders[i]; ++i )
                {
                    char* pszKey = nullptr;
                    const char* pszValue = CPLParseNameValue(papszHeaders[i], &pszKey);
                    // Content-Length is returned as 0
                    if( pszKey && pszValue && !EQUAL(pszKey, "Content-Length") )
                    {
                        aosMetadata.SetNameValue(pszKey, pszValue);
                    }
                    CPLFree(pszKey);
                }
                CSLDestroy(papszHeaders);
            }
            else
            {
                CPLXMLNode* psXML = CPLParseXMLString(requestHelper.sWriteFuncData.pBuffer);
                if( psXML )
                {
                    CPLXMLNode* psTagSet =
                        CPLGetXMLNode(psXML, "=Tags.TagSet");
                    if( psTagSet )
                    {
                        for( CPLXMLNode* psIter = psTagSet->psChild;
                                            psIter; psIter = psIter->psNext )
                        {
                            if( psIter->eType == CXT_Element &&
                                strcmp(psIter->pszValue, "Tag") == 0 )
                            {
                                CPLString osKey = CPLGetXMLValue(psIter, "Key", "");
                                CPLString osValue = CPLGetXMLValue(psIter, "Value", "");
                                aosMetadata.SetNameValue(osKey, osValue);
                            }
                        }
                    }
                    CPLDestroyXMLNode(psXML);
                }
            }
            bError = false;
        }

        curl_easy_cleanup(hCurlHandle);
    }
    while( bRetry );
    return bError ? nullptr : CSLDuplicate(aosMetadata.List());
}

/************************************************************************/
/*                          SetFileMetadata()                           */
/************************************************************************/

bool VSIAzureFSHandler::SetFileMetadata( const char * pszFilename,
                                        CSLConstList papszMetadata,
                                        const char* pszDomain,
                                        CSLConstList /* papszOptions */ )
{
    if( !STARTS_WITH_CI(pszFilename, GetFSPrefix()) )
        return false;

    if( pszDomain == nullptr ||
        !(EQUAL(pszDomain, "PROPERTIES") || EQUAL(pszDomain, "METADATA") || EQUAL(pszDomain, "TAGS")) )
    {
        CPLError(CE_Failure, CPLE_NotSupported,
                 "Only PROPERTIES, METADATA and TAGS domain are supported");
        return false;
    }

    auto poHandleHelper = std::unique_ptr<IVSIS3LikeHandleHelper>(
        CreateHandleHelper(pszFilename + GetFSPrefix().size(), false));
    if( poHandleHelper == nullptr )
    {
        return false;
    }

    NetworkStatisticsFileSystem oContextFS(GetFSPrefix());
    NetworkStatisticsAction oContextAction("SetFileMetadata");

    bool bRetry;
    // coverity[tainted_data]
    double dfRetryDelay = CPLAtof(CPLGetConfigOption("GDAL_HTTP_RETRY_DELAY",
                                CPLSPrintf("%f", CPL_HTTP_RETRY_DELAY)));
    const int nMaxRetry = atoi(CPLGetConfigOption("GDAL_HTTP_MAX_RETRY",
                                   CPLSPrintf("%d",CPL_HTTP_MAX_RETRY)));
    int nRetryCount = 0;

    bool bRet = false;

    // Compose XML content for TAGS
    CPLString osXML;
    if( EQUAL(pszDomain, "TAGS") )
    {
        CPLXMLNode* psXML = CPLCreateXMLNode(nullptr, CXT_Element, "?xml");
        CPLAddXMLAttributeAndValue(psXML, "version", "1.0");
        CPLAddXMLAttributeAndValue(psXML, "encoding", "UTF-8");
        CPLXMLNode* psTags = CPLCreateXMLNode(nullptr, CXT_Element, "Tags");
        psXML->psNext = psTags;
        CPLXMLNode* psTagSet = CPLCreateXMLNode(psTags, CXT_Element, "TagSet");
        for( int i = 0; papszMetadata && papszMetadata[i]; ++i )
        {
            char* pszKey = nullptr;
            const char* pszValue = CPLParseNameValue(papszMetadata[i], &pszKey);
            if( pszKey && pszValue )
            {
                CPLXMLNode* psTag =
                    CPLCreateXMLNode(psTagSet, CXT_Element, "Tag");
                CPLCreateXMLElementAndValue(psTag, "Key", pszKey);
                CPLCreateXMLElementAndValue(psTag, "Value", pszValue);
            }
            CPLFree(pszKey);
        }

        char* pszXML = CPLSerializeXMLTree(psXML);
        osXML = pszXML;
        CPLFree(pszXML);
        CPLDestroyXMLNode(psXML);
    }

    do
    {
        bRetry = false;
        CURL* hCurlHandle = curl_easy_init();

        if( EQUAL(pszDomain, "PROPERTIES") )
            poHandleHelper->AddQueryParameter("comp", "properties");
        else if( EQUAL(pszDomain, "METADATA") )
            poHandleHelper->AddQueryParameter("comp", "metadata");
        else
            poHandleHelper->AddQueryParameter("comp", "tags");

        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_CUSTOMREQUEST, "PUT");
        if( !osXML.empty() )
        {
            unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_POSTFIELDS, osXML.c_str() );
        }

        struct curl_slist* headers = static_cast<struct curl_slist*>(
            CPLHTTPSetOptions(hCurlHandle,
                              poHandleHelper->GetURL().c_str(),
                              nullptr));

        CPLStringList aosList;
        if( EQUAL(pszDomain, "PROPERTIES") || EQUAL(pszDomain, "METADATA") )
        {
            for( CSLConstList papszIter = papszMetadata; papszIter && *papszIter; ++papszIter )
            {
                char* pszKey = nullptr;
                const char* pszValue = CPLParseNameValue(*papszIter, &pszKey);
                if( pszKey && pszValue )
                {
                    const char* pszHeader = CPLSPrintf("%s: %s", pszKey, pszValue);
                    aosList.AddString(pszHeader);
                    headers = curl_slist_append(headers, pszHeader);
                }
                CPLFree(pszKey);
            }
        }

        CPLString osContentLength;
        osContentLength.Printf("Content-Length: %d",
                                static_cast<int>(osXML.size()));
        headers = curl_slist_append(headers, osContentLength.c_str());
        if( !osXML.empty() )
        {
            headers = curl_slist_append(headers, "Content-Type: application/xml; charset=UTF-8");
            headers = VSICurlMergeHeaders(headers,
                            poHandleHelper->GetCurlHeaders("PUT", headers,
                                                            osXML.c_str(),
                                                            osXML.size()));
        }
        else
        {
            headers = VSICurlMergeHeaders(headers,
                                    poHandleHelper->GetCurlHeaders("PUT", headers));
        }
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_HTTPHEADER, headers);

        NetworkStatisticsLogger::LogPUT(osXML.size());

        CurlRequestHelper requestHelper;
        const long response_code =
            requestHelper.perform(hCurlHandle, headers, this, poHandleHelper.get());

        if( response_code != 200 && response_code != 204 )
        {
            // Look if we should attempt a retry
            const double dfNewRetryDelay = CPLHTTPGetNewRetryDelay(
                static_cast<int>(response_code), dfRetryDelay,
                requestHelper.sWriteFuncHeaderData.pBuffer, requestHelper.szCurlErrBuf);
            if( dfNewRetryDelay > 0 &&
                nRetryCount < nMaxRetry )
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                            "HTTP error code: %d - %s. "
                            "Retrying again in %.1f secs",
                            static_cast<int>(response_code),
                            poHandleHelper->GetURL().c_str(),
                            dfRetryDelay);
                CPLSleep(dfRetryDelay);
                dfRetryDelay = dfNewRetryDelay;
                nRetryCount++;
                bRetry = true;
            }
            else
            {
                CPLDebug(GetDebugKey(), "SetFileMetadata on %s failed: %s",
                         pszFilename,
                         requestHelper.sWriteFuncData.pBuffer
                         ? requestHelper.sWriteFuncData.pBuffer
                         : "(null)");
            }
        }
        else
        {
            bRet = true;
        }

        curl_easy_cleanup(hCurlHandle);
    }
    while( bRetry );
    return bRet;
}

/************************************************************************/
/*                      GetStreamingFilename()                          */
/************************************************************************/

std::string VSIAzureFSHandler::GetStreamingFilename(const std::string& osFilename) const
{
    if( STARTS_WITH(osFilename.c_str(), GetFSPrefix().c_str()) )
        return "/vsiaz_streaming/" + osFilename.substr(GetFSPrefix().size());
    return osFilename;
}

/************************************************************************/
/*                          VSIAzureWriteHandle                         */
/************************************************************************/

class VSIAzureWriteHandle final : public VSIAppendWriteHandle
{
    CPL_DISALLOW_COPY_ASSIGN(VSIAzureWriteHandle)

    std::unique_ptr<VSIAzureBlobHandleHelper> m_poHandleHelper{};
    CPLStringList                             m_aosOptions{};

    bool                Send(bool bIsLastBlock) override;
    bool                SendInternal(bool bInitOnly, bool bIsLastBlock);

    void                InvalidateParentDirectory();

    public:
        VSIAzureWriteHandle( VSIAzureFSHandler* poFS,
                          const char* pszFilename,
                          VSIAzureBlobHandleHelper* poHandleHelper,
                          CSLConstList papszOptions );
        virtual ~VSIAzureWriteHandle();
};

/************************************************************************/
/*                        GetAzureBufferSize()                          */
/************************************************************************/

int GetAzureBufferSize()
{
    int nBufferSize;
    int nChunkSizeMB = atoi(CPLGetConfigOption("VSIAZ_CHUNK_SIZE", "4"));
    if( nChunkSizeMB <= 0 || nChunkSizeMB > 4 )
        nBufferSize = 4 * 1024 * 1024;
    else
        nBufferSize = nChunkSizeMB * 1024 * 1024;

    // For testing only !
    const char* pszChunkSizeBytes =
        CPLGetConfigOption("VSIAZ_CHUNK_SIZE_BYTES", nullptr);
    if( pszChunkSizeBytes )
        nBufferSize = atoi(pszChunkSizeBytes);
    if( nBufferSize <= 0 || nBufferSize > 4 * 1024 * 1024 )
        nBufferSize = 4 * 1024 * 1024;
    return nBufferSize;
}

/************************************************************************/
/*                       VSIAzureWriteHandle()                          */
/************************************************************************/

VSIAzureWriteHandle::VSIAzureWriteHandle( VSIAzureFSHandler* poFS,
                                    const char* pszFilename,
                                    VSIAzureBlobHandleHelper* poHandleHelper,
                                    CSLConstList papszOptions) :
        VSIAppendWriteHandle(poFS, poFS->GetFSPrefix(), pszFilename, GetAzureBufferSize()),
        m_poHandleHelper(poHandleHelper),
        m_aosOptions(papszOptions)
{
}

/************************************************************************/
/*                      ~VSIAzureWriteHandle()                          */
/************************************************************************/

VSIAzureWriteHandle::~VSIAzureWriteHandle()
{
    Close();
}

/************************************************************************/
/*                    InvalidateParentDirectory()                       */
/************************************************************************/

void VSIAzureWriteHandle::InvalidateParentDirectory()
{
    m_poFS->InvalidateCachedData(
        m_poHandleHelper->GetURLNoKVP().c_str() );

    CPLString osFilenameWithoutSlash(m_osFilename);
    if( !osFilenameWithoutSlash.empty() && osFilenameWithoutSlash.back() == '/' )
        osFilenameWithoutSlash.resize( osFilenameWithoutSlash.size() - 1 );
    m_poFS->InvalidateDirContent( CPLGetDirname(osFilenameWithoutSlash) );
}

/************************************************************************/
/*                             Send()                                   */
/************************************************************************/

bool VSIAzureWriteHandle::Send(bool bIsLastBlock)
{
    if( !bIsLastBlock )
    {
        CPLAssert( m_nBufferOff == m_nBufferSize );
        if( m_nCurOffset == static_cast<vsi_l_offset>(m_nBufferSize) )
        {
            // First full buffer ? Then create the blob empty
            if( !SendInternal( true, false ) )
                return false;
        }
    }
    return SendInternal( false, bIsLastBlock );
}

/************************************************************************/
/*                          SendInternal()                              */
/************************************************************************/

bool VSIAzureWriteHandle::SendInternal(bool bInitOnly, bool bIsLastBlock)
{
    NetworkStatisticsFileSystem oContextFS("/vsiaz/");
    NetworkStatisticsFile oContextFile(m_osFilename);
    NetworkStatisticsAction oContextAction("Write");

    bool bSuccess = true;
    const bool bSingleBlock = bIsLastBlock &&
                ( m_nCurOffset <= static_cast<vsi_l_offset>(m_nBufferSize) );

    // coverity[tainted_data]
    const int nMaxRetry = atoi(CPLGetConfigOption("GDAL_HTTP_MAX_RETRY",
                                   CPLSPrintf("%d",CPL_HTTP_MAX_RETRY)));
    // coverity[tainted_data]
    double dfRetryDelay = CPLAtof(CPLGetConfigOption("GDAL_HTTP_RETRY_DELAY",
                                CPLSPrintf("%f", CPL_HTTP_RETRY_DELAY)));
    int nRetryCount = 0;
    bool bHasAlreadyHandled409 = false;
    bool bRetry;
    do
    {
        bRetry = false;

        m_nBufferOffReadCallback = 0;
        CURL* hCurlHandle = curl_easy_init();

        m_poHandleHelper->ResetQueryParameters();
        if( !bSingleBlock && !bInitOnly )
        {
            m_poHandleHelper->AddQueryParameter("comp", "appendblock");
        }

        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_UPLOAD, 1L);
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_READFUNCTION, ReadCallBackBuffer);
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_READDATA,
                         static_cast<VSIAppendWriteHandle*>(this));

        struct curl_slist* headers = static_cast<struct curl_slist*>(
            CPLHTTPSetOptions(hCurlHandle,
                              m_poHandleHelper->GetURL().c_str(),
                              nullptr));
        headers = VSICurlSetCreationHeadersFromOptions(headers,
                                                       m_aosOptions.List(),
                                                       m_osFilename.c_str());

        CPLString osContentLength; // leave it in this scope
        if( bSingleBlock )
        {
            unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_INFILESIZE, m_nBufferOff);
            if( m_nBufferOff )
                headers = curl_slist_append(headers, "Expect: 100-continue");
            osContentLength.Printf("Content-Length: %d", m_nBufferOff);
            headers = curl_slist_append(headers, osContentLength.c_str());
            headers = curl_slist_append(headers, "x-ms-blob-type: BlockBlob");
        }
        else if( bInitOnly )
        {
            unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_INFILESIZE, 0);
            headers = curl_slist_append(headers, "Content-Length: 0");
            headers = curl_slist_append(headers, "x-ms-blob-type: AppendBlob");
        }
        else
        {
            unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_INFILESIZE, m_nBufferOff);
            osContentLength.Printf("Content-Length: %d", m_nBufferOff);
            headers = curl_slist_append(headers, osContentLength.c_str());
            headers = curl_slist_append(headers, "x-ms-blob-type: AppendBlob");
            CPLString osAppendPos;
            vsi_l_offset nStartOffset = m_nCurOffset - m_nBufferOff;
            osAppendPos.Printf("x-ms-blob-condition-appendpos: " CPL_FRMT_GUIB, nStartOffset);
            headers = curl_slist_append(headers, osAppendPos.c_str());
        }

        headers = VSICurlMergeHeaders(headers,
                        m_poHandleHelper->GetCurlHeaders("PUT", headers));
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_HTTPHEADER, headers);

        CurlRequestHelper requestHelper;
        const long response_code =
            requestHelper.perform(hCurlHandle, headers, m_poFS, m_poHandleHelper.get());

        NetworkStatisticsLogger::LogPUT(m_nBufferOff);

        if( !bHasAlreadyHandled409 && response_code == 409 )
        {
            bHasAlreadyHandled409 = true;
            CPLDebug(cpl::down_cast<VSIAzureFSHandler*>(m_poFS)->GetDebugKey(),
                     "%s",
                        requestHelper.sWriteFuncData.pBuffer
                        ? requestHelper.sWriteFuncData.pBuffer
                        : "(null)");

            // The blob type is invalid for this operation
            // Delete the file, and retry
            if( cpl::down_cast<VSIAzureFSHandler*>(m_poFS)->
                    DeleteObject(m_osFilename) == 0 )
            {
                bRetry = true;
            }
        }
        else if( response_code != 201 )
        {
            // Look if we should attempt a retry
            const double dfNewRetryDelay = CPLHTTPGetNewRetryDelay(
                static_cast<int>(response_code), dfRetryDelay,
                requestHelper.sWriteFuncHeaderData.pBuffer, requestHelper.szCurlErrBuf);
            if( dfNewRetryDelay > 0 &&
                nRetryCount < nMaxRetry )
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                            "HTTP error code: %d - %s. "
                            "Retrying again in %.1f secs",
                            static_cast<int>(response_code),
                            m_poHandleHelper->GetURL().c_str(),
                            dfRetryDelay);
                CPLSleep(dfRetryDelay);
                dfRetryDelay = dfNewRetryDelay;
                nRetryCount++;
                bRetry = true;
            }
            else
            {
                CPLDebug(cpl::down_cast<VSIAzureFSHandler*>(m_poFS)->GetDebugKey(),
                        "%s",
                            requestHelper.sWriteFuncData.pBuffer
                            ? requestHelper.sWriteFuncData.pBuffer
                            : "(null)");
                CPLError(CE_Failure, CPLE_AppDefined,
                            "PUT of %s failed",
                            m_osFilename.c_str());
                bSuccess = false;
            }
        }
        else
        {
            InvalidateParentDirectory();
        }

        curl_easy_cleanup(hCurlHandle);
    } while( bRetry );

    return bSuccess;
}

/************************************************************************/
/*                            ClearCache()                              */
/************************************************************************/

void VSIAzureFSHandler::ClearCache()
{
    IVSIS3LikeFSHandler::ClearCache();

    VSIAzureBlobHandleHelper::ClearCache();
}

/************************************************************************/
/*                                Open()                                */
/************************************************************************/

VSIVirtualHandle* VSIAzureFSHandler::Open( const char *pszFilename,
                                        const char *pszAccess,
                                        bool bSetError,
                                        CSLConstList papszOptions )
{
    if( !STARTS_WITH_CI(pszFilename, GetFSPrefix()) )
        return nullptr;

    if( strchr(pszAccess, 'w') != nullptr || strchr(pszAccess, 'a') != nullptr )
    {
        if( strchr(pszAccess, '+') != nullptr && !SupportsRandomWrite(pszFilename, true) )
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                        "w+ not supported for /vsiaz, unless "
                        "CPL_VSIL_USE_TEMP_FILE_FOR_RANDOM_WRITE is set to YES");
            errno = EACCES;
            return nullptr;
        }

        VSIAzureBlobHandleHelper* poHandleHelper =
            VSIAzureBlobHandleHelper::BuildFromURI(pszFilename + GetFSPrefix().size(),
                                            GetFSPrefix().c_str());
        if( poHandleHelper == nullptr )
            return nullptr;
        auto poHandle = new VSIAzureWriteHandle(this, pszFilename, poHandleHelper, papszOptions);
        if( strchr(pszAccess, '+') != nullptr)
        {
            return VSICreateUploadOnCloseFile(poHandle);
        }
        return poHandle;
    }

    return
        VSICurlFilesystemHandlerBase::Open(pszFilename, pszAccess, bSetError, papszOptions);
}

/************************************************************************/
/*                        SupportsRandomWrite()                         */
/************************************************************************/

bool VSIAzureFSHandler::SupportsRandomWrite( const char* /* pszPath */, bool bAllowLocalTempFile )
{
    return bAllowLocalTempFile &&
           CPLTestBool(CPLGetConfigOption("CPL_VSIL_USE_TEMP_FILE_FOR_RANDOM_WRITE", "NO"));
}

/************************************************************************/
/*                          GetURLFromFilename()                        */
/************************************************************************/

CPLString VSIAzureFSHandler::GetURLFromFilename( const CPLString& osFilename )
{
    CPLString osFilenameWithoutPrefix = osFilename.substr(GetFSPrefix().size());
    VSIAzureBlobHandleHelper* poHandleHelper =
        VSIAzureBlobHandleHelper::BuildFromURI( osFilenameWithoutPrefix, GetFSPrefix() );
    if( poHandleHelper == nullptr )
        return CPLString();
    CPLString osURL( poHandleHelper->GetURLNoKVP() );
    delete poHandleHelper;
    return osURL;
}

/************************************************************************/
/*                          CreateHandleHelper()                        */
/************************************************************************/

IVSIS3LikeHandleHelper* VSIAzureFSHandler::CreateHandleHelper(const char* pszURI,
                                                           bool)
{
    return VSIAzureBlobHandleHelper::BuildFromURI(pszURI, GetFSPrefix().c_str());
}

/************************************************************************/
/*                         InvalidateRecursive()                        */
/************************************************************************/

void VSIAzureFSHandler::InvalidateRecursive( const CPLString& osDirnameIn )
{
    // As Azure directories disappear as soon there is no remaining file
    // we may need to invalidate the whole hierarchy
    CPLString osDirname(osDirnameIn);
    while( osDirname.size() > GetFSPrefix().size() )
    {
        InvalidateDirContent(osDirname);
        InvalidateCachedData( GetURLFromFilename(osDirname) );
        osDirname = CPLGetDirname(osDirname);
    }
}

/************************************************************************/
/*                               Unlink()                               */
/************************************************************************/

int VSIAzureFSHandler::Unlink( const char *pszFilename )
{
    int ret = IVSIS3LikeFSHandler::Unlink(pszFilename);
    if( ret != 0 )
        return ret;

    InvalidateRecursive(CPLGetDirname(pszFilename));
    return 0;
}

/************************************************************************/
/*                               Mkdir()                                */
/************************************************************************/

int VSIAzureFSHandler::MkdirInternal( const char *pszDirname, long /* nMode */, bool bDoStatCheck )
{
    if( !STARTS_WITH_CI(pszDirname, GetFSPrefix()) )
        return -1;

    NetworkStatisticsFileSystem oContextFS(GetFSPrefix());
    NetworkStatisticsAction oContextAction("Mkdir");

    CPLString osDirname(pszDirname);
    if( !osDirname.empty() && osDirname.back() != '/' )
        osDirname += "/";

    if( bDoStatCheck )
    {
        VSIStatBufL sStat;
        if( VSIStatL(osDirname, &sStat) == 0 &&
            sStat.st_mode == S_IFDIR )
        {
            CPLDebug(GetDebugKey(), "Directory %s already exists", osDirname.c_str());
            errno = EEXIST;
            return -1;
        }
    }

    CPLString osDirnameWithoutEndSlash(osDirname);
    osDirnameWithoutEndSlash.resize( osDirnameWithoutEndSlash.size() - 1 );
    if( osDirnameWithoutEndSlash.size() > GetFSPrefix().size() &&
        osDirnameWithoutEndSlash.find('/', GetFSPrefix().size()) == std::string::npos )
    {
        return CreateContainer(osDirnameWithoutEndSlash);
    }

    InvalidateCachedData( GetURLFromFilename(osDirname) );
    InvalidateCachedData( GetURLFromFilename(osDirnameWithoutEndSlash) );
    InvalidateDirContent( CPLGetDirname(osDirnameWithoutEndSlash) );

    VSILFILE* fp = VSIFOpenL((osDirname + GDAL_MARKER_FOR_DIR).c_str(),
                             "wb");
    if( fp != nullptr )
    {
        CPLErrorReset();
        VSIFCloseL(fp);
        return CPLGetLastErrorType() == CPLE_None ? 0 : -1;
    }
    else
    {
        return -1;
    }
}

int VSIAzureFSHandler::Mkdir( const char * pszDirname, long nMode )
{
    return MkdirInternal(pszDirname, nMode, true);
}

/************************************************************************/
/*                        CreateContainer()                             */
/************************************************************************/

int VSIAzureFSHandler::CreateContainer( const std::string& osDirname )
{
    CPLString osDirnameWithoutPrefix = osDirname.substr(GetFSPrefix().size());
    auto poS3HandleHelper =
        std::unique_ptr<IVSIS3LikeHandleHelper>(
            CreateHandleHelper(osDirnameWithoutPrefix, false));
    if( poS3HandleHelper == nullptr )
    {
        return -1;
    }

    int nRet = 0;

    bool bRetry;

    const int nMaxRetry = atoi(CPLGetConfigOption("GDAL_HTTP_MAX_RETRY",
                                   CPLSPrintf("%d",CPL_HTTP_MAX_RETRY)));
    // coverity[tainted_data]
    double dfRetryDelay = CPLAtof(CPLGetConfigOption("GDAL_HTTP_RETRY_DELAY",
                                CPLSPrintf("%f", CPL_HTTP_RETRY_DELAY)));
    int nRetryCount = 0;

    do
    {
        poS3HandleHelper->AddQueryParameter("restype", "container");

        bRetry = false;
        CURL* hCurlHandle = curl_easy_init();
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_CUSTOMREQUEST, "PUT");

        struct curl_slist* headers = static_cast<struct curl_slist*>(
            CPLHTTPSetOptions(hCurlHandle,
                              poS3HandleHelper->GetURL().c_str(),
                              nullptr));
        headers = curl_slist_append(headers, "Content-Length: 0");
        headers = VSICurlMergeHeaders(headers,
                        poS3HandleHelper->GetCurlHeaders("PUT", headers));
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_HTTPHEADER, headers);

        CurlRequestHelper requestHelper;
        const long response_code =
            requestHelper.perform(hCurlHandle, headers, this, poS3HandleHelper.get());

        NetworkStatisticsLogger::LogPUT(0);

        if( response_code != 201)
        {
            // Look if we should attempt a retry
            const double dfNewRetryDelay = CPLHTTPGetNewRetryDelay(
                static_cast<int>(response_code), dfRetryDelay,
                requestHelper.sWriteFuncHeaderData.pBuffer, requestHelper.szCurlErrBuf);
            if( dfNewRetryDelay > 0 &&
                nRetryCount < nMaxRetry )
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                            "HTTP error code: %d - %s. "
                            "Retrying again in %.1f secs",
                            static_cast<int>(response_code),
                            poS3HandleHelper->GetURL().c_str(),
                            dfRetryDelay);
                CPLSleep(dfRetryDelay);
                dfRetryDelay = dfNewRetryDelay;
                nRetryCount++;
                bRetry = true;
            }
            else
            {
                CPLDebug(GetDebugKey(), "%s",
                         requestHelper.sWriteFuncData.pBuffer
                         ? requestHelper.sWriteFuncData.pBuffer
                         : "(null)");
                CPLError(CE_Failure, CPLE_AppDefined, "Creation of container %s failed",
                         osDirname.c_str());
                nRet = -1;
            }
        }
        else
        {
            InvalidateCachedData(poS3HandleHelper->GetURLNoKVP().c_str());
            InvalidateDirContent( GetFSPrefix().c_str() );
        }

        curl_easy_cleanup(hCurlHandle);
    }
    while( bRetry );

    return nRet;
}

/************************************************************************/
/*                               Rmdir()                                */
/************************************************************************/

int VSIAzureFSHandler::Rmdir( const char * pszDirname )
{
    if( !STARTS_WITH_CI(pszDirname, GetFSPrefix()) )
        return -1;

    NetworkStatisticsFileSystem oContextFS(GetFSPrefix());
    NetworkStatisticsAction oContextAction("Rmdir");

    CPLString osDirname(pszDirname);
    if( !osDirname.empty() && osDirname.back() != '/' )
        osDirname += "/";

    VSIStatBufL sStat;
    if( VSIStatL(osDirname, &sStat) != 0 )
    {
        InvalidateCachedData(
            GetURLFromFilename(osDirname.substr(0, osDirname.size() - 1)) );
        // The directory might have not been created by GDAL, and thus lacking the
        // GDAL marker file, so do not turn non-existence as an error
        return 0;
    }
    else if( sStat.st_mode != S_IFDIR )
    {
        CPLDebug(GetDebugKey(), "%s is not a directory", pszDirname);
        errno = ENOTDIR;
        return -1;
    }

    char** papszFileList = ReadDirEx(osDirname, 1);
    bool bEmptyDir = (papszFileList != nullptr && EQUAL(papszFileList[0], ".") &&
                      papszFileList[1] == nullptr);
    CSLDestroy(papszFileList);
    if( !bEmptyDir )
    {
        CPLDebug(GetDebugKey(), "%s is not empty", pszDirname);
        errno = ENOTEMPTY;
        return -1;
    }

    CPLString osDirnameWithoutEndSlash(osDirname);
    osDirnameWithoutEndSlash.resize( osDirnameWithoutEndSlash.size() - 1 );
    if( osDirnameWithoutEndSlash.size() > GetFSPrefix().size() &&
        osDirnameWithoutEndSlash.find('/', GetFSPrefix().size()) == std::string::npos )
    {
        return DeleteContainer(osDirnameWithoutEndSlash);
    }

    InvalidateCachedData( GetURLFromFilename(osDirname) );
    InvalidateCachedData( GetURLFromFilename(osDirnameWithoutEndSlash) );
    InvalidateRecursive( CPLGetDirname(osDirnameWithoutEndSlash) );
    if( osDirnameWithoutEndSlash.find('/', GetFSPrefix().size()) ==
                                                        std::string::npos )
    {
        CPLDebug(GetDebugKey(), "%s is a container", pszDirname);
        errno = ENOTDIR;
        return -1;
    }

    if( DeleteObject((osDirname + GDAL_MARKER_FOR_DIR).c_str()) == 0 )
        return 0;
    // The directory might have not been created by GDAL, and thus lacking the
    // GDAL marker file, so check if is there, and if not, return success.
    if( VSIStatL(osDirname, &sStat) != 0 )
        return 0;
    return -1;
}

/************************************************************************/
/*                        DeleteContainer()                             */
/************************************************************************/

int VSIAzureFSHandler::DeleteContainer( const std::string& osDirname )
{
    CPLString osDirnameWithoutPrefix = osDirname.substr(GetFSPrefix().size());
    auto poS3HandleHelper =
        std::unique_ptr<IVSIS3LikeHandleHelper>(
            CreateHandleHelper(osDirnameWithoutPrefix, false));
    if( poS3HandleHelper == nullptr )
    {
        return -1;
    }

    int nRet = 0;

    bool bRetry;

    const int nMaxRetry = atoi(CPLGetConfigOption("GDAL_HTTP_MAX_RETRY",
                                   CPLSPrintf("%d",CPL_HTTP_MAX_RETRY)));
    // coverity[tainted_data]
    double dfRetryDelay = CPLAtof(CPLGetConfigOption("GDAL_HTTP_RETRY_DELAY",
                                CPLSPrintf("%f", CPL_HTTP_RETRY_DELAY)));
    int nRetryCount = 0;

    do
    {
        poS3HandleHelper->AddQueryParameter("restype", "container");

        bRetry = false;
        CURL* hCurlHandle = curl_easy_init();
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_CUSTOMREQUEST, "DELETE");

        struct curl_slist* headers = static_cast<struct curl_slist*>(
            CPLHTTPSetOptions(hCurlHandle,
                              poS3HandleHelper->GetURL().c_str(),
                              nullptr));
        headers = curl_slist_append(headers, "Content-Length: 0");
        headers = VSICurlMergeHeaders(headers,
                        poS3HandleHelper->GetCurlHeaders("DELETE", headers));
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_HTTPHEADER, headers);

        CurlRequestHelper requestHelper;
        const long response_code =
            requestHelper.perform(hCurlHandle, headers, this, poS3HandleHelper.get());

        NetworkStatisticsLogger::LogPUT(0);

        if( response_code != 202)
        {
            // Look if we should attempt a retry
            const double dfNewRetryDelay = CPLHTTPGetNewRetryDelay(
                static_cast<int>(response_code), dfRetryDelay,
                requestHelper.sWriteFuncHeaderData.pBuffer, requestHelper.szCurlErrBuf);
            if( dfNewRetryDelay > 0 &&
                nRetryCount < nMaxRetry )
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                            "HTTP error code: %d - %s. "
                            "Retrying again in %.1f secs",
                            static_cast<int>(response_code),
                            poS3HandleHelper->GetURL().c_str(),
                            dfRetryDelay);
                CPLSleep(dfRetryDelay);
                dfRetryDelay = dfNewRetryDelay;
                nRetryCount++;
                bRetry = true;
            }
            else
            {
                CPLDebug(GetDebugKey(), "%s",
                         requestHelper.sWriteFuncData.pBuffer
                         ? requestHelper.sWriteFuncData.pBuffer
                         : "(null)");
                CPLError(CE_Failure, CPLE_AppDefined, "Deletion of container %s failed",
                         osDirname.c_str());
                nRet = -1;
            }
        }
        else
        {
            InvalidateCachedData(poS3HandleHelper->GetURLNoKVP().c_str());
            InvalidateDirContent( GetFSPrefix().c_str() );
        }

        curl_easy_cleanup(hCurlHandle);
    }
    while( bRetry );

    return nRet;
}

/************************************************************************/
/*                            CopyObject()                              */
/************************************************************************/

int VSIAzureFSHandler::CopyObject( const char *oldpath, const char *newpath,
                                   CSLConstList /* papszMetadata */ )
{
    NetworkStatisticsFileSystem oContextFS(GetFSPrefix());
    NetworkStatisticsAction oContextAction("CopyObject");

    CPLString osTargetNameWithoutPrefix = newpath + GetFSPrefix().size();
    auto poS3HandleHelper =
        std::unique_ptr<IVSIS3LikeHandleHelper>(
            CreateHandleHelper(osTargetNameWithoutPrefix, false));
    if( poS3HandleHelper == nullptr )
    {
        return -1;
    }

    CPLString osSourceNameWithoutPrefix = oldpath + GetFSPrefix().size();
    auto poS3HandleHelperSource =
        std::unique_ptr<IVSIS3LikeHandleHelper>(
            CreateHandleHelper(osSourceNameWithoutPrefix, false));
    if( poS3HandleHelperSource == nullptr )
    {
        return -1;
    }

    CPLString osSourceHeader("x-ms-copy-source: ");
    osSourceHeader += poS3HandleHelperSource->GetURLNoKVP();

    int nRet = 0;

    bool bRetry;

    const int nMaxRetry = atoi(CPLGetConfigOption("GDAL_HTTP_MAX_RETRY",
                                   CPLSPrintf("%d",CPL_HTTP_MAX_RETRY)));
    // coverity[tainted_data]
    double dfRetryDelay = CPLAtof(CPLGetConfigOption("GDAL_HTTP_RETRY_DELAY",
                                CPLSPrintf("%f", CPL_HTTP_RETRY_DELAY)));
    int nRetryCount = 0;

    do
    {
        bRetry = false;
        CURL* hCurlHandle = curl_easy_init();
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_CUSTOMREQUEST, "PUT");

        struct curl_slist* headers = static_cast<struct curl_slist*>(
            CPLHTTPSetOptions(hCurlHandle,
                              poS3HandleHelper->GetURL().c_str(),
                              nullptr));
        headers = curl_slist_append(headers, osSourceHeader.c_str());
        headers = VSICurlSetContentTypeFromExt(headers, newpath);
        headers = curl_slist_append(headers, "Content-Length: 0");
        headers = VSICurlMergeHeaders(headers,
                        poS3HandleHelper->GetCurlHeaders("PUT", headers));
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_HTTPHEADER, headers);

        CurlRequestHelper requestHelper;
        const long response_code =
            requestHelper.perform(hCurlHandle, headers, this, poS3HandleHelper.get());

        NetworkStatisticsLogger::LogPUT(0);

        if( response_code != 202)
        {
            // Look if we should attempt a retry
            const double dfNewRetryDelay = CPLHTTPGetNewRetryDelay(
                static_cast<int>(response_code), dfRetryDelay,
                requestHelper.sWriteFuncHeaderData.pBuffer, requestHelper.szCurlErrBuf);
            if( dfNewRetryDelay > 0 &&
                nRetryCount < nMaxRetry )
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                            "HTTP error code: %d - %s. "
                            "Retrying again in %.1f secs",
                            static_cast<int>(response_code),
                            poS3HandleHelper->GetURL().c_str(),
                            dfRetryDelay);
                CPLSleep(dfRetryDelay);
                dfRetryDelay = dfNewRetryDelay;
                nRetryCount++;
                bRetry = true;
            }
            else
            {
                CPLDebug(GetDebugKey(), "%s",
                         requestHelper.sWriteFuncData.pBuffer
                         ? requestHelper.sWriteFuncData.pBuffer
                         : "(null)");
                CPLError(CE_Failure, CPLE_AppDefined, "Copy of %s to %s failed",
                         oldpath, newpath);
                nRet = -1;
            }
        }
        else
        {
            InvalidateCachedData(poS3HandleHelper->GetURLNoKVP().c_str());

            CPLString osFilenameWithoutSlash(newpath);
            if( !osFilenameWithoutSlash.empty() && osFilenameWithoutSlash.back() == '/' )
                osFilenameWithoutSlash.resize( osFilenameWithoutSlash.size() - 1 );

            InvalidateDirContent( CPLGetDirname(osFilenameWithoutSlash) );
        }

        curl_easy_cleanup(hCurlHandle);
    }
    while( bRetry );

    return nRet;
}

/************************************************************************/
/*                             PutBlock()                               */
/************************************************************************/

CPLString VSIAzureFSHandler::PutBlock(const CPLString& osFilename,
                                    int nPartNumber,
                                    const void* pabyBuffer,
                                    size_t nBufferSize,
                                    IVSIS3LikeHandleHelper *poS3HandleHelper,
                                    int nMaxRetry,
                                    double dfRetryDelay,
                                    CSLConstList papszOptions)
{
    NetworkStatisticsFileSystem oContextFS(GetFSPrefix());
    NetworkStatisticsFile oContextFile(osFilename);
    NetworkStatisticsAction oContextAction("PutBlock");

    bool bRetry;
    int nRetryCount = 0;
    CPLString osBlockId;
    osBlockId.Printf("%012d", nPartNumber);

    CPLString osContentLength;
    osContentLength.Printf("Content-Length: %d", static_cast<int>(nBufferSize));

    bool bHasAlreadyHandled409 = false;

    do
    {
        bRetry = false;

        poS3HandleHelper->AddQueryParameter("comp", "block");
        poS3HandleHelper->AddQueryParameter("blockid", osBlockId);

        CURL* hCurlHandle = curl_easy_init();
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_UPLOAD, 1L);
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_READFUNCTION,
                         PutData::ReadCallBackBuffer);
        PutData putData;
        putData.pabyData = static_cast<const GByte*>(pabyBuffer);
        putData.nOff = 0;
        putData.nTotalSize = nBufferSize;
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_READDATA, &putData);
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_INFILESIZE, nBufferSize);

        struct curl_slist* headers = static_cast<struct curl_slist*>(
            CPLHTTPSetOptions(hCurlHandle,
                            poS3HandleHelper->GetURL().c_str(),
                            nullptr));
        headers = VSICurlSetCreationHeadersFromOptions(headers,
                                                       papszOptions,
                                                       osFilename.c_str());
        headers = curl_slist_append(headers, osContentLength.c_str());
        headers = VSICurlMergeHeaders(headers,
                        poS3HandleHelper->GetCurlHeaders("PUT", headers,
                                                            pabyBuffer,
                                                            nBufferSize));

        CurlRequestHelper requestHelper;
        const long response_code =
            requestHelper.perform(hCurlHandle, headers, this, poS3HandleHelper);

        NetworkStatisticsLogger::LogPUT(nBufferSize);

        if( !bHasAlreadyHandled409 && response_code == 409 )
        {
            bHasAlreadyHandled409 = true;
            CPLDebug(GetDebugKey(),
                     "%s",
                        requestHelper.sWriteFuncData.pBuffer
                        ? requestHelper.sWriteFuncData.pBuffer
                        : "(null)");

            // The blob type is invalid for this operation
            // Delete the file, and retry
            if( DeleteObject(osFilename) == 0 )
            {
                bRetry = true;
            }
        }
        else if( (response_code != 200 && response_code != 201) ||
            requestHelper.sWriteFuncHeaderData.pBuffer == nullptr )
        {
            // Look if we should attempt a retry
            const double dfNewRetryDelay = CPLHTTPGetNewRetryDelay(
                static_cast<int>(response_code), dfRetryDelay,
                requestHelper.sWriteFuncHeaderData.pBuffer, requestHelper.szCurlErrBuf);
            if( dfNewRetryDelay > 0 &&
                nRetryCount < nMaxRetry )
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                            "HTTP error code: %d - %s. "
                            "Retrying again in %.1f secs",
                            static_cast<int>(response_code),
                            poS3HandleHelper->GetURL().c_str(),
                            dfRetryDelay);
                CPLSleep(dfRetryDelay);
                dfRetryDelay = dfNewRetryDelay;
                nRetryCount++;
                bRetry = true;
            }
            else
            {
                CPLDebug(GetDebugKey(), "%s",
                        requestHelper.sWriteFuncData.pBuffer ?
                        requestHelper.sWriteFuncData.pBuffer : "(null)");
                CPLError(CE_Failure, CPLE_AppDefined, "PutBlock(%d) of %s failed",
                            nPartNumber, osFilename.c_str());
                osBlockId.clear();
            }
        }

        curl_easy_cleanup(hCurlHandle);
    }
    while( bRetry );

    return osBlockId;
}

/************************************************************************/
/*                           PutBlockList()                             */
/************************************************************************/

bool VSIAzureFSHandler::PutBlockList(const CPLString& osFilename,
                                    const std::vector<CPLString>& aosBlockIds,
                                    IVSIS3LikeHandleHelper *poS3HandleHelper,
                                    int nMaxRetry,
                                    double dfRetryDelay)
{
    bool bSuccess = true;

    NetworkStatisticsFileSystem oContextFS(GetFSPrefix());
    NetworkStatisticsFile oContextFile(osFilename);
    NetworkStatisticsAction oContextAction("PutBlockList");

    CPLString osXML = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<BlockList>\n";
    for( const auto& osBlockId: aosBlockIds )
    {
        osXML += "<Latest>" + osBlockId + "</Latest>\n";
    }
    osXML += "</BlockList>\n";

    CPLString osContentLength;
    osContentLength.Printf("Content-Length: %d", static_cast<int>(osXML.size()));

    int nRetryCount = 0;
    bool bRetry;
    do
    {
        bRetry = false;

        poS3HandleHelper->AddQueryParameter("comp", "blocklist");

        PutData putData;
        putData.pabyData = reinterpret_cast<const GByte*>(osXML.data());
        putData.nOff = 0;
        putData.nTotalSize = osXML.size();

        CURL* hCurlHandle = curl_easy_init();
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_UPLOAD, 1L);
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_READFUNCTION,
                         PutData::ReadCallBackBuffer);
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_READDATA, &putData);
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_INFILESIZE,
                        static_cast<int>(osXML.size()));
        unchecked_curl_easy_setopt(hCurlHandle, CURLOPT_CUSTOMREQUEST, "PUT");

        struct curl_slist* headers = static_cast<struct curl_slist*>(
            CPLHTTPSetOptions(hCurlHandle,
                            poS3HandleHelper->GetURL().c_str(),
                            nullptr));
        headers = curl_slist_append(headers, osContentLength.c_str());
        headers = VSICurlMergeHeaders(headers,
                        poS3HandleHelper->GetCurlHeaders("PUT", headers,
                                                            osXML.c_str(),
                                                            osXML.size()));

        CurlRequestHelper requestHelper;
        const long response_code =
            requestHelper.perform(hCurlHandle, headers, this, poS3HandleHelper);

        NetworkStatisticsLogger::LogPUT(osXML.size());

        if( response_code != 201 )
        {
            // Look if we should attempt a retry
            const double dfNewRetryDelay = CPLHTTPGetNewRetryDelay(
                static_cast<int>(response_code), dfRetryDelay,
                requestHelper.sWriteFuncHeaderData.pBuffer, requestHelper.szCurlErrBuf);
            if( dfNewRetryDelay > 0 &&
                nRetryCount < nMaxRetry )
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                            "HTTP error code: %d - %s. "
                            "Retrying again in %.1f secs",
                            static_cast<int>(response_code),
                            poS3HandleHelper->GetURL().c_str(),
                            dfRetryDelay);
                CPLSleep(dfRetryDelay);
                dfRetryDelay = dfNewRetryDelay;
                nRetryCount++;
                bRetry = true;
            }
            else
            {
                CPLDebug(GetDebugKey(), "%s",
                    requestHelper.sWriteFuncData.pBuffer ? requestHelper.sWriteFuncData.pBuffer : "(null)");
                CPLError(CE_Failure, CPLE_AppDefined,
                        "PutBlockList of %s  failed",
                        osFilename.c_str());
                bSuccess = false;
            }
        }

        curl_easy_cleanup(hCurlHandle);
    }
    while( bRetry );

    return bSuccess;
}

/************************************************************************/
/*                           GetFileList()                              */
/************************************************************************/

char** VSIAzureFSHandler::GetFileList( const char *pszDirname,
                                    int nMaxFiles,
                                    bool* pbGotFileList )
{
    return GetFileList(pszDirname, nMaxFiles, true, pbGotFileList);
}


char** VSIAzureFSHandler::GetFileList( const char *pszDirname,
                                       int nMaxFiles,
                                       bool bCacheEntries,
                                       bool* pbGotFileList )
{
    if( ENABLE_DEBUG )
        CPLDebug(GetDebugKey(), "GetFileList(%s)" , pszDirname);

    *pbGotFileList = false;

    char** papszOptions = CSLSetNameValue(nullptr,
                                "MAXFILES", CPLSPrintf("%d", nMaxFiles));
    papszOptions = CSLSetNameValue(papszOptions,
                            "CACHE_ENTRIES", bCacheEntries ? "YES" : "NO");
    auto dir = OpenDir(pszDirname, 0, papszOptions);
    CSLDestroy(papszOptions);
    if( !dir )
    {
        return nullptr;
    }
    CPLStringList aosFileList;
    while( true )
    {
        auto entry = dir->NextDirEntry();
        if( !entry )
        {
            break;
        }
        aosFileList.AddString(entry->pszName);

        if( nMaxFiles > 0 && aosFileList.size() >= nMaxFiles )
            break;
    }
    delete dir;
    *pbGotFileList = true;
    return aosFileList.StealList();
}


/************************************************************************/
/*                           GetOptions()                               */
/************************************************************************/

const char* VSIAzureFSHandler::GetOptions()
{
    static CPLString osOptions(
        CPLString("<Options>") +
    "  <Option name='AZURE_STORAGE_CONNECTION_STRING' type='string' "
        "description='Connection string that contains account name and "
        "secret key'/>"
    "  <Option name='AZURE_STORAGE_ACCOUNT' type='string' "
        "description='Storage account. To use with AZURE_STORAGE_ACCESS_KEY'/>"
    "  <Option name='AZURE_STORAGE_ACCESS_KEY' type='string' "
        "description='Secret key'/>"
    "  <Option name='AZURE_NO_SIGN_REQUEST' type='boolean' "
        "description='Whether to disable signing of requests' default='NO'/>"
    "  <Option name='VSIAZ_CHUNK_SIZE' type='int' "
        "description='Size in MB for chunks of files that are uploaded' "
        "default='4' min='1' max='4'/>" +
        VSICurlFilesystemHandlerBase::GetOptionsStatic() +
        "</Options>");
    return osOptions.c_str();
}

/************************************************************************/
/*                           GetSignedURL()                             */
/************************************************************************/

char* VSIAzureFSHandler::GetSignedURL(const char* pszFilename, CSLConstList papszOptions )
{
    if( !STARTS_WITH_CI(pszFilename, GetFSPrefix()) )
        return nullptr;

    VSIAzureBlobHandleHelper* poHandleHelper =
        VSIAzureBlobHandleHelper::BuildFromURI(pszFilename + GetFSPrefix().size(),
                                               GetFSPrefix().c_str(),
                                               papszOptions);
    if( poHandleHelper == nullptr )
    {
        return nullptr;
    }

    CPLString osRet(poHandleHelper->GetSignedURL(papszOptions));

    delete poHandleHelper;
    return CPLStrdup(osRet);
}

/************************************************************************/
/*                            OpenDir()                                 */
/************************************************************************/

VSIDIR* VSIAzureFSHandler::OpenDir( const char *pszPath,
                                      int nRecurseDepth,
                                      const char* const *papszOptions)
{
    if( nRecurseDepth > 0)
    {
        return VSIFilesystemHandler::OpenDir(pszPath, nRecurseDepth, papszOptions);
    }

    if( !STARTS_WITH_CI(pszPath, GetFSPrefix()) )
        return nullptr;

    NetworkStatisticsFileSystem oContextFS(GetFSPrefix());
    NetworkStatisticsAction oContextAction("OpenDir");

    CPLString osDirnameWithoutPrefix = pszPath + GetFSPrefix().size();
    if( !osDirnameWithoutPrefix.empty() &&
                                osDirnameWithoutPrefix.back() == '/' )
    {
        osDirnameWithoutPrefix.resize(osDirnameWithoutPrefix.size()-1);
    }

    CPLString osBucket(osDirnameWithoutPrefix);
    CPLString osObjectKey;
    size_t nSlashPos = osDirnameWithoutPrefix.find('/');
    if( nSlashPos != std::string::npos )
    {
        osBucket = osDirnameWithoutPrefix.substr(0, nSlashPos);
        osObjectKey = osDirnameWithoutPrefix.substr(nSlashPos+1);
    }

    auto poHandleHelper = std::unique_ptr<IVSIS3LikeHandleHelper>(
        CreateHandleHelper(osBucket, true));
    if( poHandleHelper == nullptr )
    {
        return nullptr;
    }

    VSIDIRAz* dir = new VSIDIRAz(this);
    dir->nRecurseDepth = nRecurseDepth;
    dir->poFS = this;
    dir->poHandleHelper = std::move(poHandleHelper);
    dir->osBucket = osBucket;
    dir->osObjectKey = osObjectKey;
    dir->nMaxFiles = atoi(CSLFetchNameValueDef(papszOptions, "MAXFILES", "0"));
    dir->bCacheEntries = CPLTestBool(
        CSLFetchNameValueDef(papszOptions, "CACHE_ENTRIES", "YES"));
    dir->m_osFilterPrefix = CSLFetchNameValueDef(papszOptions, "PREFIX", "");
    dir->m_bSynthetizeMissingDirectories = CPLTestBool(
        CSLFetchNameValueDef(papszOptions, "SYNTHETIZE_MISSING_DIRECTORIES", "NO"));
    if( !dir->IssueListDir() )
    {
        delete dir;
        return nullptr;
    }

    return dir;
}

/************************************************************************/
/*                           VSIAzureHandle()                           */
/************************************************************************/

VSIAzureHandle::VSIAzureHandle( VSIAzureFSHandler* poFSIn,
                          const char* pszFilename,
                          VSIAzureBlobHandleHelper* poHandleHelper ) :
        VSICurlHandle(poFSIn, pszFilename, poHandleHelper->GetURLNoKVP()),
        m_poHandleHelper(poHandleHelper)
{
    m_osQueryString = poHandleHelper->GetSASQueryString();
}

/************************************************************************/
/*                          GetCurlHeaders()                            */
/************************************************************************/

struct curl_slist* VSIAzureHandle::GetCurlHeaders( const CPLString& osVerb,
                                const struct curl_slist* psExistingHeaders )
{
    return m_poHandleHelper->GetCurlHeaders( osVerb, psExistingHeaders );
}

/************************************************************************/
/*                         IsDirectoryFromExists()                      */
/************************************************************************/

bool VSIAzureHandle::IsDirectoryFromExists( const char* /*pszVerb*/,
                                            int response_code )
{
    if( response_code != 404 )
        return false;

    CPLString osDirname(m_osFilename);
    if( osDirname.size() > poFS->GetFSPrefix().size() && osDirname.back() == '/' )
        osDirname.resize(osDirname.size() - 1);
    bool bIsDir;
    if( poFS->ExistsInCacheDirList(osDirname, &bIsDir) )
        return bIsDir;

    bool bGotFileList = false;
    char** papszDirContent = reinterpret_cast<VSIAzureFSHandler*>(poFS)
                        ->GetFileList( osDirname, 1, false, &bGotFileList );
    CSLDestroy(papszDirContent);
    return bGotFileList;
}

} /* end of namespace cpl */


#endif // DOXYGEN_SKIP
//! @endcond

/************************************************************************/
/*                      VSIInstallAzureFileHandler()                    */
/************************************************************************/

/*!
 \brief Install /vsiaz/ Microsoft Azure Blob file system handler
 (requires libcurl)

 \verbatim embed:rst
 See :ref:`/vsiaz/ documentation <vsiaz>`
 \endverbatim

 @since GDAL 2.3
 */

void VSIInstallAzureFileHandler( void )
{
    VSIFileManager::InstallHandler( "/vsiaz/", new cpl::VSIAzureFSHandler );
}

#endif /* HAVE_CURL */
