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() const;
 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         @param modif
 228             Modification date and time for this file.
 229     */
 230     wxFSFile(wxInputStream* stream, const wxString& location,
 231              const wxString& mimetype, const wxString& anchor,
 232              wxDateTime modif);
 233
 234     /**
 235         Detaches the stream from the wxFSFile object. That is, the
 236         stream obtained with GetStream() will continue its existance
 237         after the wxFSFile object is deleted.
 238
 239         You will have to delete the stream yourself.
 240     */
 241     void DetachStream();
 242
 243     /**
 244         Returns anchor (if present). The term of @b anchor can be easily
 245         explained using few examples:
 246
 247         @verbatim
 248         index.htm#anchor                      // 'anchor' is anchor
 249         index/wx001.htm                       // NO anchor here!
 250         archive/main.zip#zip:index.htm#global // 'global'
 251         archive/main.zip#zip:index.htm        // NO anchor here!
 252         @endverbatim
 253
 254         Usually an anchor is presented only if the MIME type is 'text/html'.
 255         But it may have some meaning with other files; for example myanim.avi#200
 256         may refer to position in animation or reality.wrl#MyView may refer
 257         to a predefined view in VRML.
 258     */
 259     const wxString& GetAnchor() const;
 260
 261     /**
 262         Returns full location of the file, including path and protocol.
 263
 264         Examples:
 265         @verbatim
 266         http://www.wxwidgets.org
 267         http://www.ms.mff.cuni.cz/~vsla8348/wxhtml/archive.zip#zip:info.txt
 268         file:/home/vasek/index.htm
 269         relative-file.htm
 270         @endverbatim
 271     */
 272     const wxString& GetLocation() const;
 273
 274     /**
 275         Returns the MIME type of the content of this file.
 276
 277         It is either extension-based (see wxMimeTypesManager) or extracted from
 278         HTTP protocol Content-Type header.
 279     */
 280     const wxString& GetMimeType() const;
 281
 282     /**
 283         Returns time when this file was modified.
 284     */
 285     wxDateTime GetModificationTime() const;
 286
 287     /**
 288         Returns pointer to the stream.
 289
 290         You can use the returned stream to directly access data.
 291         You may suppose that the stream provide Seek and GetSize functionality
 292         (even in the case of the HTTP protocol which doesn't provide
 293         this by default. wxHtml uses local cache to work around
 294         this and to speed up the connection).
 295     */
 296     wxInputStream* GetStream() const;
 297 };
 298
 299
 300
 301 /**
 302     @class wxFileSystemHandler
 303
 304     Classes derived from wxFileSystemHandler are used to access virtual file systems.
 305
 306     Its public interface consists of two methods: wxFileSystemHandler::CanOpen
 307     and wxFileSystemHandler::OpenFile.
 308
 309     It provides additional protected methods to simplify the process
 310     of opening the file: GetProtocol(), GetLeftLocation(), GetRightLocation(),
 311     GetAnchor(), GetMimeTypeFromExt().
 312
 313     Please have a look at overview (see wxFileSystem) if you don't know how locations
 314     are constructed.
 315
 316     Also consult the @ref overview_fs_wxhtmlfs "list of available handlers".
 317
 318     Note that the handlers are shared by all instances of wxFileSystem.
 319
 320     @remarks
 321     wxHTML library provides handlers for local files and HTTP or FTP protocol.
 322
 323     @note
 324     The location parameter passed to OpenFile() or CanOpen() methods is always an
 325     absolute path. You don't need to check the FS's current path.
 326
 327     @beginWxPerlOnly
 328     In wxPerl, you need to derive your file system handler class
 329     from Wx::PlFileSystemHandler.
 330     @endWxPerlOnly
 331
 332     @library{wxbase}
 333     @category{vfs}
 334
 335     @see wxFileSystem, wxFSFile, @ref overview_fs
 336 */
 337 class wxFileSystemHandler : public wxObject
 338 {
 339 public:
 340     /**
 341         Constructor.
 342     */
 343     wxFileSystemHandler();
 344
 345     /**
 346         Returns @true if the handler is able to open this file. This function doesn't
 347         check whether the file exists or not, it only checks if it knows the protocol.
 348         Example:
 349
 350         @code
 351         bool MyHand::CanOpen(const wxString& location)
 352         {
 353             return (GetProtocol(location) == "http");
 354         }
 355         @endcode
 356
 357         Must be overridden in derived handlers.
 358     */
 359     virtual bool CanOpen(const wxString& location) = 0;
 360
 361     /**
 362         Works like ::wxFindFirstFile().
 363
 364         Returns the name of the first filename (within filesystem's current path)
 365         that matches @e wildcard. @a flags may be one of wxFILE (only files),
 366         wxDIR (only directories) or 0 (both).
 367
 368         This method is only called if CanOpen() returns @true.
 369     */
 370     virtual wxString FindFirst(const wxString& wildcard,
 371                                int flags = 0);
 372
 373     /**
 374         Returns next filename that matches parameters passed to wxFileSystem::FindFirst.
 375
 376         This method is only called if CanOpen() returns @true and FindFirst()
 377         returned a non-empty string.
 378     */
 379     virtual wxString FindNext();
 380
 381     /**
 382         Returns the anchor if present in the location.
 383         See wxFSFile::GetAnchor for details.
 384
 385         Example:
 386         @code
 387         GetAnchor("index.htm#chapter2") == "chapter2"
 388         @endcode
 389
 390         @note the anchor is NOT part of the left location.
 391     */
 392     static wxString GetAnchor(const wxString& location);
 393
 394     /**
 395         Returns the left location string extracted from @e location.
 396
 397         Example:
 398         @code
 399         GetLeftLocation("file:myzipfile.zip#zip:index.htm") == "file:myzipfile.zip"
 400         @endcode
 401     */
 402     static wxString GetLeftLocation(const wxString& location);
 403
 404     /**
 405         Returns the MIME type based on @b extension of @a location.
 406         (While wxFSFile::GetMimeType() returns real MIME type - either
 407          extension-based or queried from HTTP.)
 408
 409         Example:
 410         @code
 411         GetMimeTypeFromExt("index.htm") == "text/html"
 412         @endcode
 413     */
 414     static wxString GetMimeTypeFromExt(const wxString& location);
 415
 416     /**
 417         Returns the protocol string extracted from @a location.
 418
 419         Example:
 420         @code
 421         GetProtocol("file:myzipfile.zip#zip:index.htm") == "zip"
 422         @endcode
 423     */
 424     static wxString GetProtocol(const wxString& location);
 425
 426     /**
 427         Returns the right location string extracted from @a location.
 428
 429         Example:
 430         @code
 431         GetRightLocation("file:myzipfile.zip#zip:index.htm") == "index.htm"
 432         @endcode
 433     */
 434     static wxString GetRightLocation(const wxString& location);
 435
 436     /**
 437         Opens the file and returns wxFSFile pointer or @NULL if failed.
 438         Must be overridden in derived handlers.
 439
 440         @param fs
 441             Parent FS (the FS from that OpenFile was called).
 442             See the ZIP handler for details of how to use it.
 443         @param location
 444             The absolute location of file.
 445     */
 446     virtual wxFSFile* OpenFile(wxFileSystem& fs,
 447                                const wxString& location);
 448 };
 449