GDAL
cpl_vsi_virtual.h
1 /******************************************************************************
2  * $Id$
3  *
4  * Project: VSI Virtual File System
5  * Purpose: Declarations for classes related to the virtual filesystem.
6  * These would only be normally required by applications implementing
7  * their own virtual file system classes which should be rare.
8  * The class interface may be fragile through versions.
9  * Author: Frank Warmerdam, warmerdam@pobox.com
10  *
11  ******************************************************************************
12  * Copyright (c) 2005, Frank Warmerdam <warmerdam@pobox.com>
13  * Copyright (c) 2010-2014, Even Rouault <even dot rouault at mines-paris dot org>
14  *
15  * Permission is hereby granted, free of charge, to any person obtaining a
16  * copy of this software and associated documentation files (the "Software"),
17  * to deal in the Software without restriction, including without limitation
18  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
19  * and/or sell copies of the Software, and to permit persons to whom the
20  * Software is furnished to do so, subject to the following conditions:
21  *
22  * The above copyright notice and this permission notice shall be included
23  * in all copies or substantial portions of the Software.
24  *
25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
26  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
28  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
29  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
30  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
31  * DEALINGS IN THE SOFTWARE.
32  ****************************************************************************/
33 
34 #ifndef CPL_VSI_VIRTUAL_H_INCLUDED
35 #define CPL_VSI_VIRTUAL_H_INCLUDED
36 
37 #include "cpl_vsi.h"
38 #include "cpl_vsi_error.h"
39 #include "cpl_string.h"
40 #include "cpl_multiproc.h"
41 
42 #include <map>
43 #include <vector>
44 #include <string>
45 
46 // To avoid aliasing to GetDiskFreeSpace to GetDiskFreeSpaceA on Windows
47 #ifdef GetDiskFreeSpace
48 #undef GetDiskFreeSpace
49 #endif
50 
51 /************************************************************************/
52 /* VSIVirtualHandle */
53 /************************************************************************/
54 
56 class CPL_DLL VSIVirtualHandle {
57  public:
58  virtual int Seek( vsi_l_offset nOffset, int nWhence ) = 0;
59  virtual vsi_l_offset Tell() = 0;
60  virtual size_t Read( void *pBuffer, size_t nSize, size_t nCount ) = 0;
61  virtual int ReadMultiRange( int nRanges, void ** ppData,
62  const vsi_l_offset* panOffsets,
63  const size_t* panSizes );
64  virtual size_t Write( const void *pBuffer, size_t nSize,size_t nCount)=0;
65  virtual int Eof() = 0;
66  virtual int Flush() {return 0;}
67  virtual int Close() = 0;
68  // Base implementation that only supports file extension.
69  virtual int Truncate( vsi_l_offset nNewSize );
70  virtual void *GetNativeFileDescriptor() { return nullptr; }
72  CPL_UNUSED vsi_l_offset nLength )
73  { return VSI_RANGE_STATUS_UNKNOWN; }
74 
75  virtual ~VSIVirtualHandle() { }
76 };
77 
78 /************************************************************************/
79 /* VSIFilesystemHandler */
80 /************************************************************************/
81 
82 #ifndef DOXYGEN_SKIP
83 class CPL_DLL VSIFilesystemHandler {
84 
85 public:
86 
87  virtual ~VSIFilesystemHandler() {}
88 
89  VSIVirtualHandle *Open( const char *pszFilename,
90  const char *pszAccess );
91 
92  virtual VSIVirtualHandle *Open( const char *pszFilename,
93  const char *pszAccess,
94  bool bSetError ) = 0;
95  virtual int Stat( const char *pszFilename, VSIStatBufL *pStatBuf, int nFlags) = 0;
96  virtual int Unlink( const char *pszFilename )
97  { (void) pszFilename; errno=ENOENT; return -1; }
98  virtual int Mkdir( const char *pszDirname, long nMode )
99  {(void)pszDirname; (void)nMode; errno=ENOENT; return -1;}
100  virtual int Rmdir( const char *pszDirname )
101  { (void) pszDirname; errno=ENOENT; return -1; }
102  virtual char **ReadDir( const char *pszDirname )
103  { (void) pszDirname; return nullptr; }
104  virtual char **ReadDirEx( const char *pszDirname, int /* nMaxFiles */ )
105  { return ReadDir(pszDirname); }
106  virtual int Rename( const char *oldpath, const char *newpath )
107  { (void) oldpath; (void)newpath; errno=ENOENT; return -1; }
108  virtual int IsCaseSensitive( const char* pszFilename )
109  { (void) pszFilename; return TRUE; }
110  virtual GIntBig GetDiskFreeSpace( const char* /* pszDirname */ ) { return -1; }
111  virtual int SupportsSparseFiles( const char* /* pszPath */ ) { return FALSE; }
112  virtual int HasOptimizedReadMultiRange(const char* /* pszPath */) { return FALSE; }
113  virtual const char* GetActualURL(const char* /*pszFilename*/) { return nullptr; }
114  virtual const char* GetOptions() { return nullptr; }
115  virtual char* GetSignedURL(const char* /*pszFilename*/, CSLConstList /* papszOptions */) { return nullptr; }
116 };
117 #endif /* #ifndef DOXYGEN_SKIP */
118 
119 /************************************************************************/
120 /* VSIFileManager */
121 /************************************************************************/
122 
123 #ifndef DOXYGEN_SKIP
124 class CPL_DLL VSIFileManager
125 {
126 private:
127  VSIFilesystemHandler *poDefaultHandler = nullptr;
128  std::map<std::string, VSIFilesystemHandler *> oHandlers{};
129 
130  VSIFileManager();
131 
132  static VSIFileManager *Get();
133 
134  CPL_DISALLOW_COPY_ASSIGN(VSIFileManager)
135 
136 public:
137  ~VSIFileManager();
138 
139  static VSIFilesystemHandler *GetHandler( const char * );
140  static void InstallHandler( const std::string& osPrefix,
141  VSIFilesystemHandler * );
142  /* RemoveHandler is never defined. */
143  /* static void RemoveHandler( const std::string& osPrefix ); */
144 
145  static char** GetPrefixes();
146 };
147 #endif /* #ifndef DOXYGEN_SKIP */
148 
149 /************************************************************************/
150 /* ==================================================================== */
151 /* VSIArchiveFilesystemHandler */
152 /* ==================================================================== */
153 /************************************************************************/
154 
155 #ifndef DOXYGEN_SKIP
156 
157 class VSIArchiveEntryFileOffset
158 {
159  public:
160  virtual ~VSIArchiveEntryFileOffset();
161 };
162 
163 typedef struct
164 {
165  char *fileName;
166  vsi_l_offset uncompressed_size;
167  VSIArchiveEntryFileOffset* file_pos;
168  int bIsDir;
169  GIntBig nModifiedTime;
170 } VSIArchiveEntry;
171 
172 class VSIArchiveContent
173 {
174 public:
175  time_t mTime = 0;
176  vsi_l_offset nFileSize = 0;
177  int nEntries = 0;
178  VSIArchiveEntry* entries = nullptr;
179 
180  ~VSIArchiveContent();
181 };
182 
183 class VSIArchiveReader
184 {
185  public:
186  virtual ~VSIArchiveReader();
187 
188  virtual int GotoFirstFile() = 0;
189  virtual int GotoNextFile() = 0;
190  virtual VSIArchiveEntryFileOffset* GetFileOffset() = 0;
191  virtual GUIntBig GetFileSize() = 0;
192  virtual CPLString GetFileName() = 0;
193  virtual GIntBig GetModifiedTime() = 0;
194  virtual int GotoFileOffset(VSIArchiveEntryFileOffset* pOffset) = 0;
195 };
196 
197 class VSIArchiveFilesystemHandler : public VSIFilesystemHandler
198 {
199  CPL_DISALLOW_COPY_ASSIGN(VSIArchiveFilesystemHandler)
200 
201 protected:
202  CPLMutex* hMutex = nullptr;
203  /* We use a cache that contains the list of files contained in a VSIArchive file as */
204  /* unarchive.c is quite inefficient in listing them. This speeds up access to VSIArchive files */
205  /* containing ~1000 files like a CADRG product */
206  std::map<CPLString,VSIArchiveContent*> oFileList{};
207 
208  virtual const char* GetPrefix() = 0;
209  virtual std::vector<CPLString> GetExtensions() = 0;
210  virtual VSIArchiveReader* CreateReader(const char* pszArchiveFileName) = 0;
211 
212 public:
213  VSIArchiveFilesystemHandler();
214  virtual ~VSIArchiveFilesystemHandler();
215 
216  int Stat( const char *pszFilename, VSIStatBufL *pStatBuf,
217  int nFlags ) override;
218  int Unlink( const char *pszFilename ) override;
219  int Rename( const char *oldpath, const char *newpath ) override;
220  int Mkdir( const char *pszDirname, long nMode ) override;
221  int Rmdir( const char *pszDirname ) override;
222  char **ReadDirEx( const char *pszDirname, int nMaxFiles ) override;
223 
224  virtual const VSIArchiveContent* GetContentOfArchive(const char* archiveFilename, VSIArchiveReader* poReader = nullptr);
225  virtual char* SplitFilename(const char *pszFilename, CPLString &osFileInArchive, int bCheckMainFileExists);
226  virtual VSIArchiveReader* OpenArchiveFile(const char* archiveFilename, const char* fileInArchiveName);
227  virtual int FindFileInArchive(const char* archiveFilename, const char* fileInArchiveName, const VSIArchiveEntry** archiveEntry);
228 };
229 
230 #endif /* #ifndef DOXYGEN_SKIP */
231 
232 VSIVirtualHandle CPL_DLL *VSICreateBufferedReaderHandle(VSIVirtualHandle* poBaseHandle);
233 VSIVirtualHandle* VSICreateBufferedReaderHandle(VSIVirtualHandle* poBaseHandle,
234  const GByte* pabyBeginningContent,
235  vsi_l_offset nCheatFileSize);
236 VSIVirtualHandle CPL_DLL *VSICreateCachedFile( VSIVirtualHandle* poBaseHandle, size_t nChunkSize = 32768, size_t nCacheSize = 0 );
237 
238 const int CPL_DEFLATE_TYPE_GZIP = 0;
239 const int CPL_DEFLATE_TYPE_ZLIB = 1;
240 const int CPL_DEFLATE_TYPE_RAW_DEFLATE = 2;
241 VSIVirtualHandle CPL_DLL *VSICreateGZipWritable( VSIVirtualHandle* poBaseHandle, int nDeflateType, int bAutoCloseBaseHandle );
242 
243 #endif /* ndef CPL_VSI_VIRTUAL_H_INCLUDED */
VSIRangeStatus
Range status.
Definition: cpl_vsi.h:174
Standard C Covers.
virtual VSIRangeStatus GetRangeStatus(vsi_l_offset nOffset, vsi_l_offset nLength)
Return if a given file range contains data or holes filled with zeroes.
Definition: cpl_vsi_virtual.h:71
unsigned char GByte
Unsigned byte type.
Definition: cpl_port.h:215
Virtual file handle.
Definition: cpl_vsi_virtual.h:56
virtual void * GetNativeFileDescriptor()
Returns the "native" file descriptor for the virtual handle.
Definition: cpl_vsi_virtual.h:70
Convenient string class based on std::string.
Definition: cpl_string.h:327
Various convenience functions for working with strings and string lists.
struct VSI_STAT64_T VSIStatBufL
Type for VSIStatL()
Definition: cpl_vsi.h:191
Unknown.
Definition: cpl_vsi.h:176
char ** CSLConstList
Type of a constant null-terminated list of nul terminated strings.
Definition: cpl_port.h:1186
unsigned long long GUIntBig
Large unsigned integer type (generally 64-bit unsigned integer type).
Definition: cpl_port.h:251
#define CPL_UNUSED
Qualifier for an argument that is unused.
Definition: cpl_port.h:940
GUIntBig vsi_l_offset
Type for a file offset.
Definition: cpl_vsi.h:139
long long GIntBig
Large signed integer type (generally 64-bit integer type).
Definition: cpl_port.h:248
virtual int Flush()
Flush pending writes to disk.
Definition: cpl_vsi_virtual.h:66
#define CPL_DISALLOW_COPY_ASSIGN(ClassName)
Helper to remove the copy and assignment constructors so that the compiler will not generate the defa...
Definition: cpl_port.h:989

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