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         The initial current path of this object will be empty
  41         (i.e. GetPath() == wxEmptyString) which means that e.g. OpenFile()
  42         or FindFirst() functions will use current working directory as
  43         current path (see also wxGetCwd).
  44     */
  45     wxFileSystem();
  46
  47     /**
  48         This static function adds new handler into the list of handlers
  49         (see wxFileSystemHandler) which provide access to virtual FS.
  50
  51         Note that if two handlers for the same protocol are added, the last
  52         added one takes precedence.
  53
  54         @note You can call:
  55               @code
  56               wxFileSystem::AddHandler(new My_FS_Handler);
  57               @endcode
  58               This is because (a) AddHandler is a static method, and (b) the
  59               handlers are deleted in wxFileSystem's destructor so that you
  60               don't have to care about it.
  61     */
  62     static void AddHandler(wxFileSystemHandler* handler);
  63
  64     /**
  65         Sets the current location. @a location parameter passed to OpenFile() is
  66         relative to this path.
  67
  68         @remarks Unless @a is_dir is @true the @a location parameter is not the
  69                  directory name but the name of the file in this directory.
  70
  71         All these commands change the path to "dir/subdir/":
  72
  73         @code
  74         ChangePathTo("dir/subdir/xh.htm");
  75         ChangePathTo("dir/subdir", true);
  76         ChangePathTo("dir/subdir/", true);
  77         @endcode
  78
  79         Example:
  80         @code
  81         f = fs->OpenFile("hello.htm"); // opens file 'hello.htm'
  82         fs->ChangePathTo("subdir/folder", true);
  83         f = fs->OpenFile("hello.htm"); // opens file 'subdir/folder/hello.htm' !!
  84         @endcode
  85
  86         @param location
  87             the new location. Its meaning depends on the value of is_dir
  88         @param is_dir
  89             if @true location is new directory.
  90             If @false (the default) location is file in the new directory.
  91     */
  92     void ChangePathTo(const wxString& location, bool is_dir = false);
  93
  94     /**
  95         Converts a wxFileName into an URL.
  96
  97         @see URLToFileName(), wxFileName
  98     */
  99     static wxString FileNameToURL(const wxFileName& filename);
 100
 101     /**
 102         Looks for the file with the given name @a file in a colon or semi-colon
 103         (depending on the current platform) separated list of directories in @a path.
 104
 105         If the file is found in any directory, returns @true and the full path
 106         of the file in @a str, otherwise returns @false and doesn't modify @a str.
 107
 108         @param pStr
 109             Receives the full path of the file, must not be @NULL
 110         @param path
 111             wxPATH_SEP-separated list of directories
 112         @param file
 113             the name of the file to look for
 114     */
 115     bool FindFileInPath(wxString* pStr, const wxString& path,
 116                         const wxString& file);
 117
 118     /**
 119         Works like ::wxFindFirstFile().
 120
 121         Returns the name of the first filename (within filesystem's current path)
 122         that matches @a wildcard.
 123
 124         @param wildcard
 125             The wildcard that the filename must match
 126         @param flags
 127             One of wxFILE (only files), wxDIR (only directories) or 0 (both).
 128     */
 129     wxString FindFirst(const wxString& wildcard, int flags = 0);
 130
 131     /**
 132         Returns the next filename that matches the parameters passed to FindFirst().
 133     */
 134     wxString FindNext();
 135
 136     /**
 137         Returns the actual path (set by wxFileSystem::ChangePathTo).
 138     */
 139     wxString GetPath() const;
 140
 141     /**
 142         This static function returns @true if there is a registered handler which can
 143         open the given location.
 144     */
 145     static bool HasHandlerForPath(const wxString& location);
 146
 147     /**
 148         Opens the file and returns a pointer to a wxFSFile object or @NULL if failed.
 149
 150         It first tries to open the file in relative scope (based on value passed to
 151         ChangePathTo() method) and then as an absolute path.
 152
 153         Note that the user is responsible for deleting the returned wxFSFile.
 154         @a flags can be one or more of the ::wxFileSystemOpenFlags values
 155         combined together.
 156
 157         A stream opened with just the default @e wxFS_READ flag may
 158         or may not be seekable depending on the underlying source.
 159
 160         Passing @e "wxFS_READ | wxFS_SEEKABLE" for @a flags will back
 161         a stream that is not natively seekable with memory or a file
 162         and return a stream that is always seekable.
 163     */
 164     wxFSFile* OpenFile(const wxString& location,
 165                        int flags = wxFS_READ);
 166
 167     /**
 168         Converts URL into a well-formed filename.
 169         The URL must use the @c file protocol.
 170     */
 171     static wxFileName URLToFileName(const wxString& url);
 172 };
 173
 174
 175
 176 /**
 177     @class wxFSFile
 178
 179     This class represents a single file opened by wxFileSystem.
 180     It provides more informations than wxWidgets' input streams
 181     (stream, filename, mime type, anchor).
 182
 183     @note Any pointer returned by a method of wxFSFile is valid only as long as
 184           the wxFSFile object exists. For example a call to GetStream()
 185           doesn't @e create the stream but only returns the pointer to it.
 186           In other words after 10 calls to GetStream() you will have obtained
 187           ten identical pointers.
 188
 189     @library{wxbase}
 190     @category{vfs,file}
 191
 192     @see wxFileSystemHandler, wxFileSystem, @ref overview_fs
 193 */
 194 class wxFSFile : public wxObject
 195 {
 196 public:
 197     /**
 198         Constructor. You probably won't use it. See the Note for details.
 199
 200         It is seldom used by the application programmer but you will need it if
 201         you are writing your own virtual FS. For example you may need something
 202         similar to wxMemoryInputStream, but because wxMemoryInputStream doesn't
 203         free the memory when destroyed and thus passing a memory stream pointer
 204         into wxFSFile constructor would lead to memory leaks, you can write your
 205         own class derived from wxFSFile:
 206
 207         @code
 208         class wxMyFSFile : public wxFSFile
 209         {
 210             private:
 211                 void *m_Mem;
 212             public:
 213                 wxMyFSFile(.....)
 214                 ~wxMyFSFile() {free(m_Mem);}
 215                     // of course dtor is virtual ;-)
 216         };
 217         @endcode
 218
 219         If you are not sure of the meaning of these params, see the description
 220         of the GetXXXX() functions.
 221
 222         @param stream
 223             The input stream that will be used to access data
 224         @param location
 225             The full location (aka filename) of the file
 226         @param mimetype
 227             MIME type of this file. It may be left empty, in which
 228             case the type will be determined from file's extension (location must
 229             not be empty in this case).
 230         @param anchor
 231             Anchor. See GetAnchor() for details.
 232         @param modif
 233             Modification date and time for this file.
 234     */
 235     wxFSFile(wxInputStream* stream, const wxString& location,
 236              const wxString& mimetype, const wxString& anchor,
 237              wxDateTime modif);
 238
 239     /**
 240         Detaches the stream from the wxFSFile object. That is, the
 241         stream obtained with GetStream() will continue its existance
 242         after the wxFSFile object is deleted.
 243
 244         You will have to delete the stream yourself.
 245     */
 246     wxInputStream* DetachStream();
 247
 248     /**
 249         Returns anchor (if present). The term of @b anchor can be easily
 250         explained using few examples:
 251
 252         @verbatim
 253         index.htm#anchor                      // 'anchor' is anchor
 254         index/wx001.htm                       // NO anchor here!
 255         archive/main.zip#zip:index.htm#global // 'global'
 256         archive/main.zip#zip:index.htm        // NO anchor here!
 257         @endverbatim
 258
 259         Usually an anchor is presented only if the MIME type is 'text/html'.
 260         But it may have some meaning with other files; for example myanim.avi#200
 261         may refer to position in animation or reality.wrl#MyView may refer
 262         to a predefined view in VRML.
 263     */
 264     const wxString& GetAnchor() const;
 265
 266     /**
 267         Returns full location of the file, including path and protocol.
 268
 269         Examples:
 270         @verbatim
 271         http://www.wxwidgets.org
 272         http://www.ms.mff.cuni.cz/~vsla8348/wxhtml/archive.zip#zip:info.txt
 273         file:/home/vasek/index.htm
 274         relative-file.htm
 275         @endverbatim
 276     */
 277     const wxString& GetLocation() const;
 278
 279     /**
 280         Returns the MIME type of the content of this file.
 281
 282         It is either extension-based (see wxMimeTypesManager) or extracted from
 283         HTTP protocol Content-Type header.
 284     */
 285     const wxString& GetMimeType() const;
 286
 287     /**
 288         Returns time when this file was modified.
 289     */
 290     wxDateTime GetModificationTime() const;
 291
 292     /**
 293         Returns pointer to the stream.
 294
 295         You can use the returned stream to directly access data.
 296         You may suppose that the stream provide Seek and GetSize functionality
 297         (even in the case of the HTTP protocol which doesn't provide
 298         this by default. wxHtml uses local cache to work around
 299         this and to speed up the connection).
 300     */
 301     wxInputStream* GetStream() const;
 302 };
 303
 304
 305
 306 /**
 307     @class wxFileSystemHandler
 308
 309     Classes derived from wxFileSystemHandler are used to access virtual file systems.
 310
 311     Its public interface consists of two methods: wxFileSystemHandler::CanOpen
 312     and wxFileSystemHandler::OpenFile.
 313
 314     It provides additional protected methods to simplify the process
 315     of opening the file: GetProtocol(), GetLeftLocation(), GetRightLocation(),
 316     GetAnchor(), GetMimeTypeFromExt().
 317
 318     Please have a look at overview (see wxFileSystem) if you don't know how locations
 319     are constructed.
 320
 321     Also consult the @ref overview_fs_wxhtmlfs "list of available handlers".
 322
 323     Note that the handlers are shared by all instances of wxFileSystem.
 324
 325     @remarks
 326     wxHTML library provides handlers for local files and HTTP or FTP protocol.
 327
 328     @note
 329     The location parameter passed to OpenFile() or CanOpen() methods is always an
 330     absolute path. You don't need to check the FS's current path.
 331
 332     @beginWxPerlOnly
 333     In wxPerl, you need to derive your file system handler class
 334     from Wx::PlFileSystemHandler.
 335     @endWxPerlOnly
 336
 337     @library{wxbase}
 338     @category{vfs}
 339
 340     @see wxFileSystem, wxFSFile, @ref overview_fs
 341 */
 342 class wxFileSystemHandler : public wxObject
 343 {
 344 public:
 345     /**
 346         Constructor.
 347     */
 348     wxFileSystemHandler();
 349
 350     /**
 351         Returns @true if the handler is able to open this file. This function doesn't
 352         check whether the file exists or not, it only checks if it knows the protocol.
 353         Example:
 354
 355         @code
 356         bool MyHand::CanOpen(const wxString& location)
 357         {
 358             return (GetProtocol(location) == "http");
 359         }
 360         @endcode
 361
 362         Must be overridden in derived handlers.
 363     */
 364     virtual bool CanOpen(const wxString& location) = 0;
 365
 366     /**
 367         Works like ::wxFindFirstFile().
 368
 369         Returns the name of the first filename (within filesystem's current path)
 370         that matches @e wildcard. @a flags may be one of wxFILE (only files),
 371         wxDIR (only directories) or 0 (both).
 372
 373         This method is only called if CanOpen() returns @true.
 374     */
 375     virtual wxString FindFirst(const wxString& wildcard,
 376                                int flags = 0);
 377
 378     /**
 379         Returns next filename that matches parameters passed to wxFileSystem::FindFirst.
 380
 381         This method is only called if CanOpen() returns @true and FindFirst()
 382         returned a non-empty string.
 383     */
 384     virtual wxString FindNext();
 385
 386     /**
 387         Returns the MIME type based on @b extension of @a location.
 388         (While wxFSFile::GetMimeType() returns real MIME type - either
 389          extension-based or queried from HTTP.)
 390
 391         Example:
 392         @code
 393         GetMimeTypeFromExt("index.htm") == "text/html"
 394         @endcode
 395     */
 396     static wxString GetMimeTypeFromExt(const wxString& location);
 397
 398     /**
 399         Opens the file and returns wxFSFile pointer or @NULL if failed.
 400         Must be overridden in derived handlers.
 401
 402         @param fs
 403             Parent FS (the FS from that OpenFile was called).
 404             See the ZIP handler for details of how to use it.
 405         @param location
 406             The absolute location of file.
 407     */
 408     virtual wxFSFile* OpenFile(wxFileSystem& fs, const wxString& location) = 0;
 409
 410 protected:
 411
 412     /**
 413         Returns the anchor if present in the location.
 414         See wxFSFile::GetAnchor for details.
 415
 416         Example:
 417         @code
 418         GetAnchor("index.htm#chapter2") == "chapter2"
 419         @endcode
 420
 421         @note the anchor is NOT part of the left location.
 422     */
 423     static wxString GetAnchor(const wxString& location);
 424
 425     /**
 426         Returns the left location string extracted from @e location.
 427
 428         Example:
 429         @code
 430         GetLeftLocation("file:myzipfile.zip#zip:index.htm") == "file:myzipfile.zip"
 431         @endcode
 432     */
 433     static wxString GetLeftLocation(const wxString& location);
 434
 435     /**
 436         Returns the protocol string extracted from @a location.
 437
 438         Example:
 439         @code
 440         GetProtocol("file:myzipfile.zip#zip:index.htm") == "zip"
 441         @endcode
 442     */
 443     static wxString GetProtocol(const wxString& location);
 444
 445     /**
 446         Returns the right location string extracted from @a location.
 447
 448         Example:
 449         @code
 450         GetRightLocation("file:myzipfile.zip#zip:index.htm") == "index.htm"
 451         @endcode
 452     */
 453     static wxString GetRightLocation(const wxString& location);
 454 };
 455