cpl_vsi_virtual.h

/******************************************************************************
 * $Id$
 *
 * 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 mines-paris dot org>
 *
 * 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.
 ****************************************************************************/

#ifndef CPL_VSI_VIRTUAL_H_INCLUDED
#define CPL_VSI_VIRTUAL_H_INCLUDED

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

#include <map>
#include <vector>
#include <string>

// To avoid aliasing to GetDiskFreeSpace to GetDiskFreeSpaceA on Windows
#ifdef GetDiskFreeSpace
#undef GetDiskFreeSpace
#endif

/************************************************************************/
/*                           VSIVirtualHandle                           */
/************************************************************************/

class 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 size_t    Write( const void *pBuffer, size_t nSize,size_t nCount)=0;
    virtual int       Eof() = 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           ~VSIVirtualHandle() { }
};

/************************************************************************/
/*                         VSIFilesystemHandler                         */
/************************************************************************/

#ifndef DOXYGEN_SKIP
class CPL_DLL VSIFilesystemHandler {

public:

    virtual ~VSIFilesystemHandler() {}

    VSIVirtualHandle *Open( const char *pszFilename,
                            const char *pszAccess );

    virtual VSIVirtualHandle *Open( const char *pszFilename,
                                    const char *pszAccess,
                                    bool bSetError ) = 0;
    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 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 char **ReadDir( const char *pszDirname )
                      { (void) pszDirname; return nullptr; }
    virtual char **ReadDirEx( const char *pszDirname, int /* nMaxFiles */ )
                      { return ReadDir(pszDirname); }
    virtual int Rename( const char *oldpath, const char *newpath )
                      { (void) oldpath; (void)newpath; 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; }
};
#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 * );
    /* RemoveHandler is never defined. */
    /* static void RemoveHandler( const std::string& osPrefix ); */

    static char** GetPrefixes();
};
#endif /* #ifndef DOXYGEN_SKIP */

/************************************************************************/
/* ==================================================================== */
/*                       VSIArchiveFilesystemHandler                   */
/* ==================================================================== */
/************************************************************************/

#ifndef DOXYGEN_SKIP

class VSIArchiveEntryFileOffset
{
    public:
        virtual ~VSIArchiveEntryFileOffset();
};

typedef struct
{
    char         *fileName;
    vsi_l_offset  uncompressed_size;
    VSIArchiveEntryFileOffset*      file_pos;
    int           bIsDir;
    GIntBig       nModifiedTime;
} VSIArchiveEntry;

class VSIArchiveContent
{
public:
    time_t       mTime = 0;
    vsi_l_offset nFileSize = 0;
    int nEntries = 0;
    VSIArchiveEntry* entries = nullptr;

    ~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 : public VSIFilesystemHandler
{
    CPL_DISALLOW_COPY_ASSIGN(VSIArchiveFilesystemHandler)

protected:
    CPLMutex* hMutex = nullptr;
    /* 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,VSIArchiveContent*>   oFileList{};

    virtual const char* GetPrefix() = 0;
    virtual std::vector<CPLString> GetExtensions() = 0;
    virtual VSIArchiveReader* CreateReader(const char* pszArchiveFileName) = 0;

public:
    VSIArchiveFilesystemHandler();
    virtual ~VSIArchiveFilesystemHandler();

    int Stat( const char *pszFilename, VSIStatBufL *pStatBuf,
              int nFlags ) override;
    int Unlink( const char *pszFilename ) override;
    int Rename( const char *oldpath, const char *newpath ) override;
    int Mkdir( const char *pszDirname, long nMode ) override;
    int Rmdir( const char *pszDirname ) 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, int bCheckMainFileExists);
    virtual VSIArchiveReader* OpenArchiveFile(const char* archiveFilename, const char* fileInArchiveName);
    virtual int FindFileInArchive(const char* archiveFilename, const char* fileInArchiveName, const VSIArchiveEntry** archiveEntry);
};

#endif /* #ifndef DOXYGEN_SKIP */

VSIVirtualHandle CPL_DLL *VSICreateBufferedReaderHandle(VSIVirtualHandle* poBaseHandle);
VSIVirtualHandle* VSICreateBufferedReaderHandle(VSIVirtualHandle* poBaseHandle,
                                                const GByte* pabyBeginningContent,
                                                vsi_l_offset nCheatFileSize);
VSIVirtualHandle CPL_DLL *VSICreateCachedFile( VSIVirtualHandle* poBaseHandle, size_t nChunkSize = 32768, 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 );

#endif /* ndef CPL_VSI_VIRTUAL_H_INCLUDED */