cpl_vsi_virtual.h

/******************************************************************************
 *
 * Project:  VSI Virtual File System
 * Purpose:  Declarations for classes related to the virtual filesystem.
 *           These would only be normally required by applications implementing
 *           their own virtual file system classes which should be rare.
 *           The class interface may be fragile through versions.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 2005, Frank Warmerdam <warmerdam@pobox.com>
 * Copyright (c) 2010-2014, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/
 
#ifndef CPL_VSI_VIRTUAL_H_INCLUDED
#define CPL_VSI_VIRTUAL_H_INCLUDED
 
#include "cpl_progress.h"
#include "cpl_vsi.h"
#include "cpl_vsi_error.h"
#include "cpl_string.h"
 
#include <cstdint>
#include <map>
#include <memory>
#include <mutex>
#include <vector>
#include <string>
 
// To avoid aliasing to GetDiskFreeSpace to GetDiskFreeSpaceA on Windows
#ifdef GetDiskFreeSpace
#undef GetDiskFreeSpace
#endif
 
// To avoid aliasing to CopyFile to CopyFileA on Windows
#ifdef CopyFile
#undef CopyFile
#endif
 
/************************************************************************/
/*                           VSIVirtualHandle                           */
/************************************************************************/

struct CPL_DLL VSIVirtualHandle
{
  public:
    virtual int Seek(vsi_l_offset nOffset, int nWhence) = 0;
    virtual vsi_l_offset Tell() = 0;
    virtual size_t Read(void *pBuffer, size_t nSize, size_t nCount) = 0;
    virtual int ReadMultiRange(int nRanges, void **ppData,
                               const vsi_l_offset *panOffsets,
                               const size_t *panSizes);

    virtual void AdviseRead(CPL_UNUSED int nRanges,
                            CPL_UNUSED const vsi_l_offset *panOffsets,
                            CPL_UNUSED const size_t *panSizes)
    {
    }

    virtual size_t GetAdviseReadTotalBytesLimit() const
    {
        return 0;
    }
 
    virtual size_t Write(const void *pBuffer, size_t nSize, size_t nCount) = 0;
 
    int Printf(CPL_FORMAT_STRING(const char *pszFormat), ...)
        CPL_PRINT_FUNC_FORMAT(2, 3);
 
    virtual void ClearErr() = 0;
 
    virtual int Eof() = 0;
 
    virtual int Error() = 0;
 
    virtual int Flush()
    {
        return 0;
    }
 
    virtual int Close() = 0;
    // Base implementation that only supports file extension.
    virtual int Truncate(vsi_l_offset nNewSize);
 
    virtual void *GetNativeFileDescriptor()
    {
        return nullptr;
    }
 
    virtual VSIRangeStatus GetRangeStatus(CPL_UNUSED vsi_l_offset nOffset,
                                          CPL_UNUSED vsi_l_offset nLength)
    {
        return VSI_RANGE_STATUS_UNKNOWN;
    }
 
    virtual bool HasPRead() const;
    virtual size_t PRead(void *pBuffer, size_t nSize,
                         vsi_l_offset nOffset) const;

    virtual void Interrupt()
    {
    }

    virtual void CancelCreation()
    {
    }
 
    // NOTE: when adding new methods, besides the "actual" implementations,
    // also consider the VSICachedFile and VSIVirtualHandleOnlyVisibleAtCloseTime one.
 
    virtual ~VSIVirtualHandle()
    {
    }
};
 
/************************************************************************/
/*                        VSIVirtualHandleCloser                        */
/************************************************************************/

struct VSIVirtualHandleCloser
 
{
    void operator()(VSIVirtualHandle *poHandle)
    {
        if (poHandle)
        {
            poHandle->Close();
            delete poHandle;
        }
    }
};

typedef std::unique_ptr<VSIVirtualHandle, VSIVirtualHandleCloser>
    VSIVirtualHandleUniquePtr;
 
/************************************************************************/
/*                        VSIProxyFileHandle                            */
/************************************************************************/
 
#ifndef DOXYGEN_SKIP
class VSIProxyFileHandle /* non final */ : public VSIVirtualHandle
{
  protected:
    VSIVirtualHandleUniquePtr m_nativeHandle{};
 
  public:
    explicit VSIProxyFileHandle(VSIVirtualHandleUniquePtr &&nativeHandle)
        : m_nativeHandle(std::move(nativeHandle))
    {
    }
 
    int Seek(vsi_l_offset nOffset, int nWhence) override
    {
        return m_nativeHandle->Seek(nOffset, nWhence);
    }
 
    vsi_l_offset Tell() override
    {
        return m_nativeHandle->Tell();
    }
 
    size_t Read(void *pBuffer, size_t nSize, size_t nCount) override
    {
        return m_nativeHandle->Read(pBuffer, nSize, nCount);
    }
 
    int ReadMultiRange(int nRanges, void **ppData,
                       const vsi_l_offset *panOffsets,
                       const size_t *panSizes) override
    {
        return m_nativeHandle->ReadMultiRange(nRanges, ppData, panOffsets,
                                              panSizes);
    }
 
    void AdviseRead(int nRanges, const vsi_l_offset *panOffsets,
                    const size_t *panSizes) override
    {
        return m_nativeHandle->AdviseRead(nRanges, panOffsets, panSizes);
    }
 
    size_t GetAdviseReadTotalBytesLimit() const override
    {
        return m_nativeHandle->GetAdviseReadTotalBytesLimit();
    }
 
    size_t Write(const void *pBuffer, size_t nSize, size_t nCount) override
    {
        return m_nativeHandle->Write(pBuffer, nSize, nCount);
    }
 
    void ClearErr() override
    {
        return m_nativeHandle->ClearErr();
    }
 
    int Eof() override
    {
        return m_nativeHandle->Eof();
    }
 
    int Error() override
    {
        return m_nativeHandle->Error();
    }
 
    int Flush() override
    {
        return m_nativeHandle->Flush();
    }
 
    int Close() override
    {
        return m_nativeHandle->Close();
    }
 
    int Truncate(vsi_l_offset nNewSize) override
    {
        return m_nativeHandle->Truncate(nNewSize);
    }
 
    void *GetNativeFileDescriptor() override
    {
        return m_nativeHandle->GetNativeFileDescriptor();
    }
 
    VSIRangeStatus GetRangeStatus(vsi_l_offset nOffset,
                                  vsi_l_offset nLength) override
    {
        return m_nativeHandle->GetRangeStatus(nOffset, nLength);
    }
 
    bool HasPRead() const override
    {
        return m_nativeHandle->HasPRead();
    }
 
    size_t PRead(void *pBuffer, size_t nSize,
                 vsi_l_offset nOffset) const override
    {
        return m_nativeHandle->PRead(pBuffer, nSize, nOffset);
    }
 
    void Interrupt() override
    {
        m_nativeHandle->Interrupt();
    }
 
    void CancelCreation() override;
};
#endif
 
/************************************************************************/
/*                         VSIFilesystemHandler                         */
/************************************************************************/
 
#ifndef DOXYGEN_SKIP
class CPL_DLL VSIFilesystemHandler
{
 
  public:
    virtual ~VSIFilesystemHandler() = default;
 
    static VSIVirtualHandleUniquePtr
    OpenStatic(const char *pszFilename, const char *pszAccess,
               bool bSetError = false, CSLConstList papszOptions = nullptr);
 
    virtual VSIVirtualHandleUniquePtr
    Open(const char *pszFilename, const char *pszAccess, bool bSetError = false,
         CSLConstList papszOptions = nullptr) = 0;
 
    virtual VSIVirtualHandleUniquePtr
    CreateOnlyVisibleAtCloseTime(const char *pszFilename,
                                 bool bEmulationAllowed,
                                 CSLConstList papszOptions);
 
    virtual int Stat(const char *pszFilename, VSIStatBufL *pStatBuf,
                     int nFlags) = 0;
 
    virtual int Unlink(const char *pszFilename)
    {
        (void)pszFilename;
        errno = ENOENT;
        return -1;
    }
 
    virtual int *UnlinkBatch(CSLConstList papszFiles);
 
    virtual int Mkdir(const char *pszDirname, long nMode)
    {
        (void)pszDirname;
        (void)nMode;
        errno = ENOENT;
        return -1;
    }
 
    virtual int Rmdir(const char *pszDirname)
    {
        (void)pszDirname;
        errno = ENOENT;
        return -1;
    }
 
    virtual int RmdirRecursive(const char *pszDirname);
 
    char **ReadDir(const char *pszDirname)
    {
        return ReadDirEx(pszDirname, 0);
    }
 
    virtual char **ReadDirEx(const char * /*pszDirname*/, int /* nMaxFiles */)
    {
        return nullptr;
    }
 
    virtual char **SiblingFiles(const char * /*pszFilename*/)
    {
        return nullptr;
    }
 
    virtual int Rename(const char *oldpath, const char *newpath,
                       GDALProgressFunc pProgressFunc, void *pProgressData)
    {
        (void)oldpath;
        (void)newpath;
        (void)pProgressFunc;
        (void)pProgressData;
        errno = ENOENT;
        return -1;
    }
 
    virtual int IsCaseSensitive(const char *pszFilename)
    {
        (void)pszFilename;
        return TRUE;
    }
 
    virtual GIntBig GetDiskFreeSpace(const char * /* pszDirname */)
    {
        return -1;
    }
 
    virtual int SupportsSparseFiles(const char * /* pszPath */)
    {
        return FALSE;
    }
 
    virtual int HasOptimizedReadMultiRange(const char * /* pszPath */)
    {
        return FALSE;
    }
 
    virtual const char *GetActualURL(const char * /*pszFilename*/)
    {
        return nullptr;
    }
 
    virtual const char *GetOptions()
    {
        return nullptr;
    }
 
    virtual char *GetSignedURL(const char * /*pszFilename*/,
                               CSLConstList /* papszOptions */)
    {
        return nullptr;
    }
 
    virtual bool Sync(const char *pszSource, const char *pszTarget,
                      const char *const *papszOptions,
                      GDALProgressFunc pProgressFunc, void *pProgressData,
                      char ***ppapszOutputs);
 
    virtual int CopyFile(const char *pszSource, const char *pszTarget,
                         VSILFILE *fpSource, vsi_l_offset nSourceSize,
                         const char *const *papszOptions,
                         GDALProgressFunc pProgressFunc, void *pProgressData);
 
    virtual int
    CopyFileRestartable(const char *pszSource, const char *pszTarget,
                        const char *pszInputPayload, char **ppszOutputPayload,
                        CSLConstList papszOptions,
                        GDALProgressFunc pProgressFunc, void *pProgressData);
 
    virtual VSIDIR *OpenDir(const char *pszPath, int nRecurseDepth,
                            const char *const *papszOptions);
 
    virtual char **GetFileMetadata(const char *pszFilename,
                                   const char *pszDomain,
                                   CSLConstList papszOptions);
 
    virtual bool SetFileMetadata(const char *pszFilename,
                                 CSLConstList papszMetadata,
                                 const char *pszDomain,
                                 CSLConstList papszOptions);
 
    virtual bool
    MultipartUploadGetCapabilities(int *pbNonSequentialUploadSupported,
                                   int *pbParallelUploadSupported,
                                   int *pbAbortSupported, size_t *pnMinPartSize,
                                   size_t *pnMaxPartSize, int *pnMaxPartCount);
 
    virtual char *MultipartUploadStart(const char *pszFilename,
                                       CSLConstList papszOptions);
 
    virtual char *MultipartUploadAddPart(const char *pszFilename,
                                         const char *pszUploadId,
                                         int nPartNumber,
                                         vsi_l_offset nFileOffset,
                                         const void *pData, size_t nDataLength,
                                         CSLConstList papszOptions);
 
    virtual bool
    MultipartUploadEnd(const char *pszFilename, const char *pszUploadId,
                       size_t nPartIdsCount, const char *const *apszPartIds,
                       vsi_l_offset nTotalSize, CSLConstList papszOptions);
 
    virtual bool MultipartUploadAbort(const char *pszFilename,
                                      const char *pszUploadId,
                                      CSLConstList papszOptions);
 
    virtual bool AbortPendingUploads(const char * /*pszFilename*/)
    {
        return true;
    }
 
    virtual std::string
    GetStreamingFilename(const std::string &osFilename) const
    {
        return osFilename;
    }
 
    virtual std::string
    GetNonStreamingFilename(const std::string &osFilename) const
    {
        return osFilename;
    }

    virtual std::string
    GetCanonicalFilename(const std::string &osFilename) const
    {
        return osFilename;
    }
 
    virtual bool IsLocal(const char * /* pszPath */) const
    {
        return true;
    }
 
    virtual bool IsArchive(const char * /* pszPath */) const
    {
        return false;
    }
 
    virtual bool SupportsSequentialWrite(const char * /* pszPath */,
                                         bool /* bAllowLocalTempFile */)
    {
        return true;
    }
 
    virtual bool SupportsRandomWrite(const char * /* pszPath */,
                                     bool /* bAllowLocalTempFile */)
    {
        return true;
    }
 
    virtual bool SupportsRead(const char * /* pszPath */)
    {
        return true;
    }
 
    virtual VSIFilesystemHandler *Duplicate(const char * /* pszPrefix */)
    {
        CPLError(CE_Failure, CPLE_NotSupported,
                 "Duplicate() not supported on this file "
                 "system");
        return nullptr;
    }

    virtual const char *GetDirectorySeparator(CPL_UNUSED const char *pszPath)
    {
        return "/";
    }
};
#endif /* #ifndef DOXYGEN_SKIP */
 
/************************************************************************/
/*                            VSIFileManager                            */
/************************************************************************/
 
#ifndef DOXYGEN_SKIP
class CPL_DLL VSIFileManager
{
  private:
    VSIFilesystemHandler *poDefaultHandler = nullptr;
    std::map<std::string, VSIFilesystemHandler *> oHandlers{};
 
    VSIFileManager();
 
    static VSIFileManager *Get();
 
    CPL_DISALLOW_COPY_ASSIGN(VSIFileManager)
 
  public:
    ~VSIFileManager();
 
    static VSIFilesystemHandler *GetHandler(const char *);
    static void InstallHandler(const std::string &osPrefix,
                               VSIFilesystemHandler *);
    static void RemoveHandler(const std::string &osPrefix);
 
    static char **GetPrefixes();
};
#endif /* #ifndef DOXYGEN_SKIP */
 
/************************************************************************/
/* ==================================================================== */
/*                       VSIArchiveFilesystemHandler                   */
/* ==================================================================== */
/************************************************************************/
 
#ifndef DOXYGEN_SKIP
 
class VSIArchiveEntryFileOffset
{
  public:
    virtual ~VSIArchiveEntryFileOffset();
};
 
class VSIArchiveEntry
{
  public:
    std::string fileName{};
    vsi_l_offset uncompressed_size = 0;
    std::unique_ptr<VSIArchiveEntryFileOffset> file_pos{};
    bool bIsDir = false;
    GIntBig nModifiedTime = 0;
};
 
class VSIArchiveContent
{
  public:
    time_t mTime = 0;
    vsi_l_offset nFileSize = 0;
    std::vector<VSIArchiveEntry> entries{};
 
    // Store list of child indices for each directory
    using DirectoryChildren = std::vector<int>;
 
    std::map<std::string, DirectoryChildren> dirIndex{};
 
    VSIArchiveContent() = default;
 
    ~VSIArchiveContent();
 
  private:
    CPL_DISALLOW_COPY_ASSIGN(VSIArchiveContent)
};
 
class VSIArchiveReader
{
  public:
    virtual ~VSIArchiveReader();
 
    virtual int GotoFirstFile() = 0;
    virtual int GotoNextFile() = 0;
    virtual VSIArchiveEntryFileOffset *GetFileOffset() = 0;
    virtual GUIntBig GetFileSize() = 0;
    virtual CPLString GetFileName() = 0;
    virtual GIntBig GetModifiedTime() = 0;
    virtual int GotoFileOffset(VSIArchiveEntryFileOffset *pOffset) = 0;
};
 
class VSIArchiveFilesystemHandler /* non final */ : public VSIFilesystemHandler
{
    CPL_DISALLOW_COPY_ASSIGN(VSIArchiveFilesystemHandler)
 
    bool FindFileInArchive(const char *archiveFilename,
                           const char *fileInArchiveName,
                           const VSIArchiveEntry **archiveEntry);
 
  protected:
    mutable std::recursive_mutex oMutex{};
 
    /* We use a cache that contains the list of files contained in a VSIArchive
     * file as */
    /* unarchive.c is quite inefficient in listing them. This speeds up access
     * to VSIArchive files */
    /* containing ~1000 files like a CADRG product */
    std::map<CPLString, std::unique_ptr<VSIArchiveContent>> oFileList{};
 
    virtual const char *GetPrefix() const = 0;
    virtual std::vector<CPLString> GetExtensions() const = 0;
    virtual std::unique_ptr<VSIArchiveReader>
    CreateReader(const char *pszArchiveFileName) = 0;
 
  public:
    VSIArchiveFilesystemHandler();
    ~VSIArchiveFilesystemHandler() override;
 
    int Stat(const char *pszFilename, VSIStatBufL *pStatBuf,
             int nFlags) override;
    char **ReadDirEx(const char *pszDirname, int nMaxFiles) override;
 
    virtual const VSIArchiveContent *
    GetContentOfArchive(const char *archiveFilename,
                        VSIArchiveReader *poReader = nullptr);
    virtual char *SplitFilename(const char *pszFilename,
                                CPLString &osFileInArchive,
                                bool bCheckMainFileExists,
                                bool bSetError) const;
    virtual std::unique_ptr<VSIArchiveReader>
    OpenArchiveFile(const char *archiveFilename, const char *fileInArchiveName);
 
    bool IsLocal(const char *pszPath) const override;
 
    bool IsArchive(const char *pszPath) const override;
 
    bool SupportsSequentialWrite(const char * /* pszPath */,
                                 bool /* bAllowLocalTempFile */) override
    {
        return false;
    }
 
    bool SupportsRandomWrite(const char * /* pszPath */,
                             bool /* bAllowLocalTempFile */) override
    {
        return false;
    }
};
 
/************************************************************************/
/*                              VSIDIR                                  */
/************************************************************************/
 
struct CPL_DLL VSIDIR
{
    VSIDIR() = default;
    virtual ~VSIDIR();
 
    virtual const VSIDIREntry *NextDirEntry() = 0;
 
  private:
    VSIDIR(const VSIDIR &) = delete;
    VSIDIR &operator=(const VSIDIR &) = delete;
};
 
#endif /* #ifndef DOXYGEN_SKIP */
 
VSIVirtualHandle CPL_DLL *
VSICreateBufferedReaderHandle(VSIVirtualHandle *poBaseHandle);
VSIVirtualHandle *
VSICreateBufferedReaderHandle(VSIVirtualHandle *poBaseHandle,
                              const GByte *pabyBeginningContent,
                              vsi_l_offset nCheatFileSize);
constexpr int VSI_CACHED_DEFAULT_CHUNK_SIZE = 32768;
VSIVirtualHandle CPL_DLL *
VSICreateCachedFile(VSIVirtualHandle *poBaseHandle,
                    size_t nChunkSize = VSI_CACHED_DEFAULT_CHUNK_SIZE,
                    size_t nCacheSize = 0);
 
const int CPL_DEFLATE_TYPE_GZIP = 0;
const int CPL_DEFLATE_TYPE_ZLIB = 1;
const int CPL_DEFLATE_TYPE_RAW_DEFLATE = 2;
VSIVirtualHandle CPL_DLL *VSICreateGZipWritable(VSIVirtualHandle *poBaseHandle,
                                                int nDeflateType,
                                                int bAutoCloseBaseHandle);
 
VSIVirtualHandle *VSICreateGZipWritable(VSIVirtualHandle *poBaseHandle,
                                        int nDeflateType,
                                        bool bAutoCloseBaseHandle, int nThreads,
                                        size_t nChunkSize,
                                        size_t nSOZIPIndexEltSize,
                                        std::vector<uint8_t> *panSOZIPIndex);
 
VSIVirtualHandle *
VSICreateUploadOnCloseFile(VSIVirtualHandleUniquePtr &&poWritableHandle,
                           VSIVirtualHandleUniquePtr &&poTmpFile,
                           const std::string &osTmpFilename);
 
#endif /* ndef CPL_VSI_VIRTUAL_H_INCLUDED */