interface/wx/filesys.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        filesys.h
   3 // Purpose:     interface of wxFileSystem, wxFileSystemHandler, wxFSFile
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9
  10 /**
  11     Open Bit Flags
  12 */
  13 enum wxFileSystemOpenFlags
  14 {
  15     wxFS_READ = 1,      /**< Open for reading */
  16     wxFS_SEEKABLE = 4   /**< Returned stream will be seekable */
  17 };
  18
  19
  20 /**
  21     @class wxFileSystem
  22
  23     This class provides an interface for opening files on different file systems.
  24     It can handle absolute and/or local filenames.
  25
  26     It uses a system of handlers (see wxFileSystemHandler) to provide access to
  27     user-defined virtual file systems.
  28
  29     @library{wxbase}
  30     @category{vfs}
  31
  32     @see wxFileSystemHandler, wxFSFile, @ref overview_fs
  33 */
  34 class wxFileSystem : public wxObject
  35 {
  36 public:
  37     /**
  38         Constructor.
  39     */
  40     wxFileSystem();
  41
  42     /**
  43         This static function adds new handler into the list of handlers
  44         (see wxFileSystemHandler) which provide access to virtual FS.
  45
  46         Note that if two handlers for the same protocol are added, the last
  47         added one takes precedence.
  48
  49         @note You can call:
  50               @code
  51               wxFileSystem::AddHandler(new My_FS_Handler);
  52               @endcode
  53               This is because (a) AddHandler is a static method, and (b) the
  54               handlers are deleted in wxFileSystem's destructor so that you
  55               don't have to care about it.
  56     */
  57     static void AddHandler(wxFileSystemHandler handler);
  58
  59     /**
  60         Sets the current location. @a location parameter passed to OpenFile() is
  61         relative to this path.
  62
  63         @remarks Unless @a is_dir is @true the @a location parameter is not the
  64                  directory name but the name of the file in this directory.
  65
  66         All these commands change the path to "dir/subdir/":
  67
  68         @code
  69         ChangePathTo("dir/subdir/xh.htm");
  70         ChangePathTo("dir/subdir", true);
  71         ChangePathTo("dir/subdir/", true);
  72         @endcode
  73
  74         Example:
  75         @code
  76         f = fs->OpenFile("hello.htm"); // opens file 'hello.htm'
  77         fs->ChangePathTo("subdir/folder", true);
  78         f = fs->OpenFile("hello.htm"); // opens file 'subdir/folder/hello.htm' !!
  79         @endcode
  80
  81         @param location
  82             the new location. Its meaning depends on the value of is_dir
  83         @param is_dir
  84             if @true location is new directory.
  85             If @false (the default) location is file in the new directory.
  86     */
  87     void ChangePathTo(const wxString& location, bool is_dir = false);
  88
  89     /**
  90         Converts a wxFileName into an URL.
  91
  92         @see URLToFileName(), wxFileName
  93     */
  94     static wxString FileNameToURL(const wxFileName& filename);
  95
  96     /**
  97         Looks for the file with the given name @a file in a colon or semi-colon
  98         (depending on the current platform) separated list of directories in @a path.
  99
 100         If the file is found in any directory, returns @true and the full path
 101         of the file in @a str, otherwise returns @false and doesn't modify @a str.
 102
 103         @param str
 104             Receives the full path of the file, must not be @NULL
 105         @param path
 106             wxPATH_SEP-separated list of directories
 107         @param file
 108             the name of the file to look for
 109     */
 110     bool FindFileInPath(wxString str, const wxString& path,
 111                         const wxString& file);
 112
 113     /**
 114         Works like ::wxFindFirstFile().
 115
 116         Returns the name of the first filename (within filesystem's current path)
 117         that matches @a wildcard.
 118
 119         @param wildcard
 120             The wildcard that the filename must match
 121         @param flags
 122             One of wxFILE (only files), wxDIR (only directories) or 0 (both).
 123     */
 124     wxString FindFirst(const wxString& wildcard, int flags = 0);
 125
 126     /**
 127         Returns the next filename that matches the parameters passed to FindFirst().
 128     */
 129     wxString FindNext();
 130
 131     /**
 132         Returns the actual path (set by wxFileSystem::ChangePathTo).
 133     */
 134     wxString GetPath();
 135
 136     /**
 137         This static function returns @true if there is a registered handler which can
 138         open the given location.
 139     */
 140     static bool HasHandlerForPath(const wxString& location);
 141
 142     /**
 143         Opens the file and returns a pointer to a wxFSFile object or @NULL if failed.
 144
 145         It first tries to open the file in relative scope (based on value passed to
 146         ChangePathTo() method) and then as an absolute path.
 147
 148         Note that the user is responsible for deleting the returned wxFSFile.
 149         @a flags can be one or more of the ::wxFileSystemOpenFlags values
 150         combined together.
 151
 152         A stream opened with just the default @e wxFS_READ flag may
 153         or may not be seekable depending on the underlying source.
 154
 155         Passing @e "wxFS_READ | wxFS_SEEKABLE" for @a flags will back
 156         a stream that is not natively seekable with memory or a file
 157         and return a stream that is always seekable.
 158     */
 159     wxFSFile* OpenFile(const wxString& location,
 160                        int flags = wxFS_READ);
 161
 162     /**
 163         Converts URL into a well-formed filename.
 164         The URL must use the @c file protocol.
 165     */
 166     static wxFileName URLToFileName(const wxString& url);
 167 };
 168
 169
 170
 171 /**
 172     @class wxFSFile
 173
 174     This class represents a single file opened by wxFileSystem.
 175     It provides more information than wxWindow's input stream
 176     (stream, filename, mime type, anchor).
 177
 178     @note Any pointer returned by a method of wxFSFile is valid only as long as
 179           the wxFSFile object exists. For example a call to GetStream()
 180           doesn't @e create the stream but only returns the pointer to it.
 181           In other words after 10 calls to GetStream() you will have obtained
 182           ten identical pointers.
 183
 184     @library{wxbase}
 185     @category{vfs}
 186
 187     @see wxFileSystemHandler, wxFileSystem, @ref overview_fs
 188 */
 189 class wxFSFile : public wxObject
 190 {
 191 public:
 192     /**
 193         Constructor. You probably won't use it. See the Note for details.
 194
 195         It is seldom used by the application programmer but you will need it if
 196         you are writing your own virtual FS. For example you may need something
 197         similar to wxMemoryInputStream, but because wxMemoryInputStream doesn't
 198         free the memory when destroyed and thus passing a memory stream pointer
 199         into wxFSFile constructor would lead to memory leaks, you can write your
 200         own class derived from wxFSFile:
 201
 202         @code
 203         class wxMyFSFile : public wxFSFile
 204         {
 205             private:
 206                 void *m_Mem;
 207             public:
 208                 wxMyFSFile(.....)
 209                 ~wxMyFSFile() {free(m_Mem);}
 210                     // of course dtor is virtual ;-)
 211         };
 212         @endcode
 213
 214         If you are not sure of the meaning of these params, see the description
 215         of the GetXXXX() functions.
 216
 217         @param stream
 218             The input stream that will be used to access data
 219         @param location
 220             The full location (aka filename) of the file
 221         @param mimetype
 222             MIME type of this file. It may be left empty, in which
 223             case the type will be determined from file's extension (location must
 224             not be empty in this case).
 225         @param anchor
 226             Anchor. See GetAnchor() for details.
 227     */
 228     wxFSFile(wxInputStream stream, const wxString& loc,
 229              const wxString& mimetype,
 230              const wxString& anchor, wxDateTime modif);
 231
 232     /**
 233         Detaches the stream from the wxFSFile object. That is, the
 234         stream obtained with GetStream() will continue its existance
 235         after the wxFSFile object is deleted.
 236
 237         You will have to delete the stream yourself.
 238     */
 239     void DetachStream();
 240
 241     /**
 242         Returns anchor (if present). The term of @b anchor can be easily
 243         explained using few examples:
 244
 245         @verbatim
 246         index.htm#anchor                      // 'anchor' is anchor
 247         index/wx001.htm                       // NO anchor here!
 248         archive/main.zip#zip:index.htm#global // 'global'
 249         archive/main.zip#zip:index.htm        // NO anchor here!
 250         @endverbatim
 251
 252         Usually an anchor is presented only if the MIME type is 'text/html'.
 253         But it may have some meaning with other files; for example myanim.avi#200
 254         may refer to position in animation or reality.wrl#MyView may refer
 255         to a predefined view in VRML.
 256     */
 257     const wxString& GetAnchor() const;
 258
 259     /**
 260         Returns full location of the file, including path and protocol.
 261
 262         Examples:
 263         @verbatim
 264         http://www.wxwidgets.org
 265         http://www.ms.mff.cuni.cz/~vsla8348/wxhtml/archive.zip#zip:info.txt
 266         file:/home/vasek/index.htm
 267         relative-file.htm
 268         @endverbatim
 269     */
 270     const wxString& GetLocation() const;
 271
 272     /**
 273         Returns the MIME type of the content of this file.
 274
 275         It is either extension-based (see wxMimeTypesManager) or extracted from
 276         HTTP protocol Content-Type header.
 277     */
 278     const wxString& GetMimeType() const;
 279
 280     /**
 281         Returns time when this file was modified.
 282     */
 283     wxDateTime GetModificationTime() const;
 284
 285     /**
 286         Returns pointer to the stream.
 287
 288         You can use the returned stream to directly access data.
 289         You may suppose that the stream provide Seek and GetSize functionality
 290         (even in the case of the HTTP protocol which doesn't provide
 291         this by default. wxHtml uses local cache to work around
 292         this and to speed up the connection).
 293     */
 294     wxInputStream* GetStream() const;
 295 };
 296
 297
 298
 299 /**
 300     @class wxFileSystemHandler
 301
 302     Classes derived from wxFileSystemHandler are used to access virtual file systems.
 303
 304     Its public interface consists of two methods: wxFileSystemHandler::CanOpen
 305     and wxFileSystemHandler::OpenFile.
 306
 307     It provides additional protected methods to simplify the process
 308     of opening the file: GetProtocol(), GetLeftLocation(), GetRightLocation(),
 309     GetAnchor(), GetMimeTypeFromExt().
 310
 311     Please have a look at overview (see wxFileSystem) if you don't know how locations
 312     are constructed.
 313
 314     Also consult the @ref overview_fs_wxhtmlfs "list of available handlers".
 315
 316     Note that the handlers are shared by all instances of wxFileSystem.
 317
 318     @remarks
 319     wxHTML library provides handlers for local files and HTTP or FTP protocol.
 320
 321     @note
 322     The location parameter passed to OpenFile() or CanOpen() methods is always an
 323     absolute path. You don't need to check the FS's current path.
 324
 325     @beginWxPerlOnly
 326     In wxPerl, you need to derive your file system handler class
 327     from Wx::PlFileSystemHandler.
 328     @endWxPerlOnly
 329
 330     @library{wxbase}
 331     @category{vfs}
 332
 333     @see wxFileSystem, wxFSFile, @ref overview_fs
 334 */
 335 class wxFileSystemHandler : public wxObject
 336 {
 337 public:
 338     /**
 339         Constructor.
 340     */
 341     wxFileSystemHandler();
 342
 343     /**
 344         Returns @true if the handler is able to open this file. This function doesn't
 345         check whether the file exists or not, it only checks if it knows the protocol.
 346         Example:
 347
 348         @code
 349         bool MyHand::CanOpen(const wxString& location)
 350         {
 351             return (GetProtocol(location) == "http");
 352         }
 353         @endcode
 354
 355         Must be overridden in derived handlers.
 356     */
 357     virtual bool CanOpen(const wxString& location);
 358
 359     /**
 360         Works like ::wxFindFirstFile().
 361
 362         Returns the name of the first filename (within filesystem's current path)
 363         that matches @e wildcard. @a flags may be one of wxFILE (only files),
 364         wxDIR (only directories) or 0 (both).
 365
 366         This method is only called if CanOpen() returns @true.
 367     */
 368     virtual wxString FindFirst(const wxString& wildcard,
 369                                int flags = 0);
 370
 371     /**
 372         Returns next filename that matches parameters passed to wxFileSystem::FindFirst.
 373
 374         This method is only called if CanOpen() returns @true and FindFirst()
 375         returned a non-empty string.
 376     */
 377     virtual wxString FindNext();
 378
 379     /**
 380         Returns the anchor if present in the location.
 381         See wxFSFile::GetAnchor for details.
 382
 383         Example:
 384         @code
 385         GetAnchor("index.htm#chapter2") == "chapter2"
 386         @endcode
 387
 388         @note the anchor is NOT part of the left location.
 389     */
 390     wxString GetAnchor(const wxString& location) const;
 391
 392     /**
 393         Returns the left location string extracted from @e location.
 394
 395         Example:
 396         @code
 397         GetLeftLocation("file:myzipfile.zip#zip:index.htm") == "file:myzipfile.zip"
 398         @endcode
 399     */
 400     wxString GetLeftLocation(const wxString& location) const;
 401
 402     /**
 403         Returns the MIME type based on @b extension of @a location.
 404         (While wxFSFile::GetMimeType() returns real MIME type - either
 405          extension-based or queried from HTTP.)
 406
 407         Example:
 408         @code
 409         GetMimeTypeFromExt("index.htm") == "text/html"
 410         @endcode
 411     */
 412     wxString GetMimeTypeFromExt(const wxString& location);
 413
 414     /**
 415         Returns the protocol string extracted from @a location.
 416
 417         Example:
 418         @code
 419         GetProtocol("file:myzipfile.zip#zip:index.htm") == "zip"
 420         @endcode
 421     */
 422     wxString GetProtocol(const wxString& location) const;
 423
 424     /**
 425         Returns the right location string extracted from @a location.
 426
 427         Example:
 428         @code
 429         GetRightLocation("file:myzipfile.zip#zip:index.htm") == "index.htm"
 430         @endcode
 431     */
 432     wxString GetRightLocation(const wxString& location) const;
 433
 434     /**
 435         Opens the file and returns wxFSFile pointer or @NULL if failed.
 436         Must be overridden in derived handlers.
 437
 438         @param fs
 439             Parent FS (the FS from that OpenFile was called).
 440             See the ZIP handler for details of how to use it.
 441         @param location
 442             The absolute location of file.
 443     */
 444     virtual wxFSFile* OpenFile(wxFileSystem& fs,
 445                                const wxString& location);
 446 };
 447