GDAL
cpl_vsi_virtual.h
1 /******************************************************************************
2  * $Id: cpl_vsi_virtual.h 36501 2016-11-25 14:09:24Z rouault $
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 NULL; }
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 NULL; }
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 };
113 #endif /* #ifndef DOXYGEN_SKIP */
114 
115 /************************************************************************/
116 /* VSIFileManager */
117 /************************************************************************/
118 
119 #ifndef DOXYGEN_SKIP
120 class CPL_DLL VSIFileManager
121 {
122 private:
123  VSIFilesystemHandler *poDefaultHandler;
124  std::map<std::string, VSIFilesystemHandler *> oHandlers;
125 
126  VSIFileManager();
127 
128  static VSIFileManager *Get();
129 
130 public:
131  ~VSIFileManager();
132 
133  static VSIFilesystemHandler *GetHandler( const char * );
134  static void InstallHandler( const std::string& osPrefix,
135  VSIFilesystemHandler * );
136  /* RemoveHandler is never defined. */
137  /* static void RemoveHandler( const std::string& osPrefix ); */
138 };
139 #endif /* #ifndef DOXYGEN_SKIP */
140 
141 /************************************************************************/
142 /* ==================================================================== */
143 /* VSIArchiveFilesystemHandler */
144 /* ==================================================================== */
145 /************************************************************************/
146 
147 #ifndef DOXYGEN_SKIP
148 
149 class VSIArchiveEntryFileOffset
150 {
151  public:
152  virtual ~VSIArchiveEntryFileOffset();
153 };
154 
155 typedef struct
156 {
157  char *fileName;
158  vsi_l_offset uncompressed_size;
159  VSIArchiveEntryFileOffset* file_pos;
160  int bIsDir;
161  GIntBig nModifiedTime;
162 } VSIArchiveEntry;
163 
164 class VSIArchiveContent
165 {
166 public:
167  time_t mTime;
168  vsi_l_offset nFileSize;
169  int nEntries;
170  VSIArchiveEntry* entries;
171 
172  VSIArchiveContent() : mTime(0), nFileSize(0), nEntries(0), entries(NULL) {}
173  ~VSIArchiveContent();
174 };
175 
176 class VSIArchiveReader
177 {
178  public:
179  virtual ~VSIArchiveReader();
180 
181  virtual int GotoFirstFile() = 0;
182  virtual int GotoNextFile() = 0;
183  virtual VSIArchiveEntryFileOffset* GetFileOffset() = 0;
184  virtual GUIntBig GetFileSize() = 0;
185  virtual CPLString GetFileName() = 0;
186  virtual GIntBig GetModifiedTime() = 0;
187  virtual int GotoFileOffset(VSIArchiveEntryFileOffset* pOffset) = 0;
188 };
189 
190 class VSIArchiveFilesystemHandler : public VSIFilesystemHandler
191 {
192 protected:
193  CPLMutex* hMutex;
194  /* We use a cache that contains the list of files contained in a VSIArchive file as */
195  /* unarchive.c is quite inefficient in listing them. This speeds up access to VSIArchive files */
196  /* containing ~1000 files like a CADRG product */
197  std::map<CPLString,VSIArchiveContent*> oFileList;
198 
199  virtual const char* GetPrefix() = 0;
200  virtual std::vector<CPLString> GetExtensions() = 0;
201  virtual VSIArchiveReader* CreateReader(const char* pszArchiveFileName) = 0;
202 
203 public:
204  VSIArchiveFilesystemHandler();
205  virtual ~VSIArchiveFilesystemHandler();
206 
207  virtual int Stat( const char *pszFilename, VSIStatBufL *pStatBuf, int nFlags ) CPL_OVERRIDE;
208  virtual int Unlink( const char *pszFilename ) CPL_OVERRIDE;
209  virtual int Rename( const char *oldpath, const char *newpath ) CPL_OVERRIDE;
210  virtual int Mkdir( const char *pszDirname, long nMode ) CPL_OVERRIDE;
211  virtual int Rmdir( const char *pszDirname ) CPL_OVERRIDE;
212  virtual char **ReadDirEx( const char *pszDirname, int nMaxFiles ) CPL_OVERRIDE;
213 
214  virtual const VSIArchiveContent* GetContentOfArchive(const char* archiveFilename, VSIArchiveReader* poReader = NULL);
215  virtual char* SplitFilename(const char *pszFilename, CPLString &osFileInArchive, int bCheckMainFileExists);
216  virtual VSIArchiveReader* OpenArchiveFile(const char* archiveFilename, const char* fileInArchiveName);
217  virtual int FindFileInArchive(const char* archiveFilename, const char* fileInArchiveName, const VSIArchiveEntry** archiveEntry);
218 };
219 
220 #endif /* #ifndef DOXYGEN_SKIP */
221 
222 VSIVirtualHandle CPL_DLL *VSICreateBufferedReaderHandle(VSIVirtualHandle* poBaseHandle);
223 VSIVirtualHandle* VSICreateBufferedReaderHandle(VSIVirtualHandle* poBaseHandle,
224  const GByte* pabyBeginningContent,
225  vsi_l_offset nCheatFileSize);
226 VSIVirtualHandle CPL_DLL *VSICreateCachedFile( VSIVirtualHandle* poBaseHandle, size_t nChunkSize = 32768, size_t nCacheSize = 0 );
227 VSIVirtualHandle CPL_DLL *VSICreateGZipWritable( VSIVirtualHandle* poBaseHandle, int bRegularZLibIn, int bAutoCloseBaseHandle );
228 
229 #endif /* ndef CPL_VSI_VIRTUAL_H_INCLUDED */
VSIRangeStatus
Range status.
Definition: cpl_vsi.h:173
Standard C Covers.
#define CPL_OVERRIDE
To be used in public headers only.
Definition: cpl_port.h:1048
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:207
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:355
Various convenience functions for working with strings and string lists.
struct VSI_STAT64_T VSIStatBufL
Type for VSIStatL()
Definition: cpl_vsi.h:190
Unknown.
Definition: cpl_vsi.h:175
unsigned long long GUIntBig
Large unsigned integer type (generally 64-bit unsigned integer type).
Definition: cpl_port.h:253
#define CPL_UNUSED
Qualifier for an argument that is unused.
Definition: cpl_port.h:1001
GUIntBig vsi_l_offset
Type for a file offset.
Definition: cpl_vsi.h:138
long long GIntBig
Large signed integer type (generally 64-bit integer type).
Definition: cpl_port.h:250
virtual int Flush()
Flush pending writes to disk.
Definition: cpl_vsi_virtual.h:66

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