include/wx/dataobj.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/dataobj.h
   3 // Purpose:     common data object classes
   4 // Author:      Vadim Zeitlin, Robert Roebling
   5 // Modified by:
   6 // Created:     26.05.99
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) wxWindows Team
   9 // Licence:     wxWindows license
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_DATAOBJ_H_BASE_
  13 #define _WX_DATAOBJ_H_BASE_
  14
  15 #ifdef __GNUG__
  16     #pragma interface "dataobjbase.h"
  17 #endif
  18
  19 // ----------------------------------------------------------------------------
  20 // headers
  21 // ----------------------------------------------------------------------------
  22
  23 #include "wx/defs.h"
  24 #include "wx/string.h"
  25 #include "wx/bitmap.h"
  26 #include "wx/list.h"
  27
  28 // ============================================================================
  29 /*
  30    Generic data transfer related classes. The class hierarchy is as follows:
  31
  32                                 - wxDataObject-
  33                                /               \
  34                               /                 \
  35             wxDataObjectSimple                  wxDataObjectComposite
  36            /           |      \
  37           /            |       \
  38    wxTextDataObject    |     wxBitmapDataObject
  39                        |
  40                wxCustomDataObject
  41
  42 */
  43 // ============================================================================
  44
  45 // ----------------------------------------------------------------------------
  46 // wxDataFormat class is declared in platform-specific headers: it represents
  47 // a format for data which may be either one of the standard ones (text,
  48 // bitmap, ...) or a custom one which is then identified by a unique string.
  49 // ----------------------------------------------------------------------------
  50
  51 /* the class interface looks like this (pseudo code):
  52
  53 class wxDataFormat
  54 {
  55 public:
  56     typedef <integral type> NativeFormat;
  57
  58     wxDataFormat(NativeFormat format = wxDF_INVALID);
  59     wxDataFormat(const wxChar *format);
  60
  61     wxDataFormat& operator=(NativeFormat format);
  62     wxDataFormat& operator=(const wxDataFormat& format);
  63
  64     bool operator==(NativeFormat format) const;
  65     bool operator!=(NativeFormat format) const;
  66
  67     void SetType(NativeFormat format);
  68     NativeFormat GetType() const;
  69
  70     wxString GetId() const;
  71     void SetId(const wxChar *format);
  72 };
  73
  74 */
  75
  76 #if defined(__WXMSW__)
  77     #include "wx/msw/ole/dataform.h"
  78 #elif defined(__WXMOTIF__)
  79     #include "wx/motif/dataform.h"
  80 #elif defined(__WXGTK__)
  81     #include "wx/gtk/dataform.h"
  82 #elif defined(__WXMAC__)
  83     #include "wx/mac/dataform.h"
  84 #elif defined(__WXPM__)
  85     #include "wx/os2/dataform.h"
  86 #endif
  87
  88 // the value for default argument to some functions (corresponds to
  89 // wxDF_INVALID)
  90 extern WXDLLEXPORT const wxDataFormat& wxFormatInvalid;
  91
  92 // ----------------------------------------------------------------------------
  93 // wxDataObject represents a piece of data which knows which formats it
  94 // supports and knows how to render itself in each of them - GetDataHere(),
  95 // and how to restore data from the buffer (SetData()).
  96 //
  97 // Although this class may be used directly (i.e. custom classes may be
  98 // derived from it), in many cases it might be simpler to use either
  99 // wxDataObjectSimple or wxDataObjectComposite classes.
 100 //
 101 // A data object may be "read only", i.e. support only GetData() functions or
 102 // "read-write", i.e. support both GetData() and SetData() (in principle, it
 103 // might be "write only" too, but this is rare). Moreover, it doesn't have to
 104 // support the same formats in Get() and Set() directions: for example, a data
 105 // object containing JPEG image might accept BMPs in GetData() because JPEG
 106 // image may be easily transformed into BMP but not in SetData(). Accordingly,
 107 // all methods dealing with formats take an additional "direction" argument
 108 // which is either SET or GET and which tells the function if the format needs
 109 // to be supported by SetData() or GetDataHere().
 110 // ----------------------------------------------------------------------------
 111
 112 class WXDLLEXPORT wxDataObjectBase
 113 {
 114 public:
 115     enum Direction
 116     {
 117         Get  = 0x01,    // format is supported by GetDataHere()
 118         Set  = 0x02,    // format is supported by SetData()
 119         Both = 0x03     // format is supported by both (unused currently)
 120     };
 121
 122     // this class is polymorphic, hence it needs a virtual dtor
 123     virtual ~wxDataObjectBase();
 124
 125     // get the best suited format for rendering our data
 126     virtual wxDataFormat GetPreferredFormat(Direction dir = Get) const = 0;
 127
 128     // get the number of formats we support
 129     virtual size_t GetFormatCount(Direction dir = Get) const = 0;
 130
 131     // return all formats in the provided array (of size GetFormatCount())
 132     virtual void GetAllFormats(wxDataFormat *formats,
 133                                Direction dir = Get) const = 0;
 134
 135     // get the (total) size of data for the given format
 136     virtual size_t GetDataSize(const wxDataFormat& format) const = 0;
 137
 138     // copy raw data (in the specified format) to the provided buffer, return
 139     // TRUE if data copied successfully, FALSE otherwise
 140     virtual bool GetDataHere(const wxDataFormat& format, void *buf) const = 0;
 141
 142     // get data from the buffer of specified length (in the given format),
 143     // return TRUE if the data was read successfully, FALSE otherwise
 144     virtual bool SetData(const wxDataFormat& WXUNUSED(format),
 145                          size_t WXUNUSED(len), const void * WXUNUSED(buf))
 146     {
 147         return FALSE;
 148     }
 149
 150     // returns TRUE if this format is supported
 151     bool IsSupported(const wxDataFormat& format, Direction dir = Get) const;
 152 };
 153
 154 // ----------------------------------------------------------------------------
 155 // include the platform-specific declarations of wxDataObject
 156 // ----------------------------------------------------------------------------
 157
 158 #if defined(__WXMSW__)
 159     #include "wx/msw/ole/dataobj.h"
 160 #elif defined(__WXMOTIF__)
 161     #include "wx/motif/dataobj.h"
 162 #elif defined(__WXGTK__)
 163     #include "wx/gtk/dataobj.h"
 164 #elif defined(__WXMAC__)
 165     #include "wx/mac/dataobj.h"
 166 #elif defined(__WXPM__)
 167     #include "wx/os2/dataobj.h"
 168 #elif defined(__WXSTUBS__)
 169     #include "wx/stubs/dnd.h"
 170 #endif
 171
 172 // ----------------------------------------------------------------------------
 173 // wxDataObjectSimple is a wxDataObject which only supports one format (in
 174 // both Get and Set directions, but you may return FALSE from GetDataHere() or
 175 // SetData() if one of them is not supported). This is the simplest possible
 176 // wxDataObject implementation.
 177 //
 178 // This is still an "abstract base class" (although it doesn't have any pure
 179 // virtual functions), to use it you should derive from it and implement
 180 // GetDataSize(), GetDataHere() and SetData() functions because the base class
 181 // versions don't do anything - they just return "not implemented".
 182 //
 183 // This class should be used when you provide data in only one format (no
 184 // conversion to/from other formats), either a standard or a custom one.
 185 // Otherwise, you should use wxDataObjectComposite or wxDataObject directly.
 186 // ----------------------------------------------------------------------------
 187
 188 class WXDLLEXPORT wxDataObjectSimple : public wxDataObject
 189 {
 190 public:
 191     // ctor takes the format we support, but it can also be set later with
 192     // SetFormat()
 193     wxDataObjectSimple(const wxDataFormat& format = wxFormatInvalid)
 194         : m_format(format)
 195         {
 196         }
 197
 198     // get/set the format we support
 199     const wxDataFormat& GetFormat() const { return m_format; }
 200     void SetFormat(const wxDataFormat& format) { m_format = format; }
 201
 202     // virtual functions to override in derived class (the base class versions
 203     // just return "not implemented")
 204     // -----------------------------------------------------------------------
 205
 206     // get the size of our data
 207     virtual size_t GetDataSize() const
 208         { return 0; }
 209
 210     // copy our data to the buffer
 211     virtual bool GetDataHere(void *WXUNUSED(buf)) const
 212         { return FALSE; }
 213
 214     // copy data from buffer to our data
 215     virtual bool SetData(size_t WXUNUSED(len), const void *WXUNUSED(buf))
 216         { return FALSE; }
 217
 218     // implement base class pure virtuals
 219     // ----------------------------------
 220     virtual wxDataFormat GetPreferredFormat(wxDataObjectBase::Direction WXUNUSED(dir) = Get) const
 221         { return m_format; }
 222     virtual size_t GetFormatCount(wxDataObjectBase::Direction WXUNUSED(dir) = Get) const
 223         { return 1; }
 224     virtual void GetAllFormats(wxDataFormat *formats,
 225                                wxDataObjectBase::Direction WXUNUSED(dir) = Get) const
 226         { *formats = m_format; }
 227     virtual size_t GetDataSize(const wxDataFormat& WXUNUSED(format)) const
 228         { return GetDataSize(); }
 229     virtual bool GetDataHere(const wxDataFormat& WXUNUSED(format),
 230                              void *buf) const
 231         { return GetDataHere(buf); }
 232     virtual bool SetData(const wxDataFormat& WXUNUSED(format),
 233                          size_t len, const void *buf)
 234         { return SetData(len, buf); }
 235
 236 private:
 237     // the one and only format we support
 238     wxDataFormat m_format;
 239 };
 240
 241 // ----------------------------------------------------------------------------
 242 // wxDataObjectComposite is the simplest way to implement wxDataObject
 243 // supporting multiple formats. It contains several wxDataObjectSimple and
 244 // supports all formats supported by any of them.
 245 //
 246 // This class shouldn't be (normally) derived from, but may be used directly.
 247 // If you need more flexibility than what it provides, you should probably use
 248 // wxDataObject directly.
 249 // ----------------------------------------------------------------------------
 250
 251 WX_DECLARE_EXPORTED_LIST(wxDataObjectSimple, wxSimpleDataObjectList);
 252
 253 class WXDLLEXPORT wxDataObjectComposite : public wxDataObject
 254 {
 255 public:
 256     // ctor
 257     wxDataObjectComposite() { m_preferred = 0; }
 258
 259     // add data object (it will be deleted by wxDataObjectComposite, hence it
 260     // must be allocated on the heap) whose format will become the preferred
 261     // one if preferred == TRUE
 262     void Add(wxDataObjectSimple *dataObject, bool preferred = FALSE);
 263
 264     // implement base class pure virtuals
 265     // ----------------------------------
 266     virtual wxDataFormat GetPreferredFormat(wxDataObjectBase::Direction dir = Get) const;
 267     virtual size_t GetFormatCount(wxDataObjectBase::Direction dir = Get) const;
 268     virtual void GetAllFormats(wxDataFormat *formats, wxDataObjectBase::Direction dir = Get) const;
 269     virtual size_t GetDataSize(const wxDataFormat& format) const;
 270     virtual bool GetDataHere(const wxDataFormat& format, void *buf) const;
 271     virtual bool SetData(const wxDataFormat& format, size_t len, const void *buf);
 272
 273 protected:
 274     // returns the pointer to the object which supports this format or NULL
 275     wxDataObjectSimple *GetObject(const wxDataFormat& format) const;
 276
 277 private:
 278     // the list of all (simple) data objects whose formats we support
 279     wxSimpleDataObjectList m_dataObjects;
 280
 281     // the index of the preferred one (0 initially, so by default the first
 282     // one is the preferred)
 283     size_t m_preferred;
 284 };
 285
 286 // ============================================================================
 287 // Standard implementations of wxDataObjectSimple which can be used directly
 288 // (i.e. without having to derive from them) for standard data type transfers.
 289 //
 290 // Note that although all of them can work with provided data, you can also
 291 // override their virtual GetXXX() functions to only provide data on demand.
 292 // ============================================================================
 293
 294 // ----------------------------------------------------------------------------
 295 // wxTextDataObject contains text data
 296 // ----------------------------------------------------------------------------
 297
 298 class WXDLLEXPORT wxTextDataObject : public wxDataObjectSimple
 299 {
 300 public:
 301     // ctor: you can specify the text here or in SetText(), or override
 302     // GetText()
 303     wxTextDataObject(const wxString& text = wxEmptyString)
 304         : wxDataObjectSimple(wxDF_TEXT), m_text(text)
 305         {
 306         }
 307
 308     // virtual functions which you may override if you want to provide text on
 309     // demand only - otherwise, the trivial default versions will be used
 310     virtual size_t GetTextLength() const { return m_text.Len() + 1; }
 311     virtual wxString GetText() const { return m_text; }
 312     virtual void SetText(const wxString& text) { m_text = text; }
 313
 314     // implement base class pure virtuals
 315     // ----------------------------------
 316     virtual size_t GetDataSize() const;
 317     virtual bool GetDataHere(void *buf) const;
 318     virtual bool SetData(size_t len, const void *buf);
 319
 320 private:
 321     wxString m_text;
 322
 323     // virtual function hiding supression
 324     size_t GetDataSize(const wxDataFormat& format) const
 325         { return(wxDataObjectSimple::GetDataSize(format)); }
 326     bool GetDataHere(const wxDataFormat& format, void *pBuf) const
 327         { return(wxDataObjectSimple::GetDataHere(format, pBuf)); }
 328     bool SetData(const wxDataFormat& format, size_t nLen, const void* pBuf)
 329         { return(wxDataObjectSimple::SetData(format, nLen, pBuf)); }
 330 };
 331
 332 // ----------------------------------------------------------------------------
 333 // wxBitmapDataObject contains a bitmap
 334 // ----------------------------------------------------------------------------
 335
 336 class WXDLLEXPORT wxBitmapDataObjectBase : public wxDataObjectSimple
 337 {
 338 public:
 339     // ctor: you can specify the bitmap here or in SetBitmap(), or override
 340     // GetBitmap()
 341     wxBitmapDataObjectBase(const wxBitmap& bitmap = wxNullBitmap)
 342         : wxDataObjectSimple(wxDF_BITMAP), m_bitmap(bitmap)
 343         {
 344         }
 345
 346     // virtual functions which you may override if you want to provide data on
 347     // demand only - otherwise, the trivial default versions will be used
 348     virtual wxBitmap GetBitmap() const { return m_bitmap; }
 349     virtual void SetBitmap(const wxBitmap& bitmap) { m_bitmap = bitmap; }
 350
 351 protected:
 352     wxBitmap m_bitmap;
 353 };
 354
 355 // ----------------------------------------------------------------------------
 356 // wxFileDataObject contains a list of filenames
 357 //
 358 // NB: notice that this is a "write only" object, it can only be filled with
 359 //     data from drag and drop operation.
 360 // ----------------------------------------------------------------------------
 361
 362 class WXDLLEXPORT wxFileDataObjectBase : public wxDataObjectSimple
 363 {
 364 public:
 365     // ctor: use AddFile() later to fill the array
 366     wxFileDataObjectBase() : wxDataObjectSimple(wxDF_FILENAME) { }
 367
 368     // get a reference to our array
 369     const wxArrayString& GetFilenames() const { return m_filenames; }
 370
 371     // the Get() functions do nothing for us
 372     virtual size_t GetDataSize() const { return 0; }
 373     virtual bool GetDataHere(void *WXUNUSED(buf)) const { return FALSE; }
 374
 375 protected:
 376     wxArrayString m_filenames;
 377
 378 private:
 379     // Virtual function hiding supression
 380     size_t GetDataSize(const wxDataFormat& format) const
 381         { return(wxDataObjectSimple::GetDataSize(format)); }
 382     bool GetDataHere(const wxDataFormat& format, void* pBuf) const
 383         { return(wxDataObjectSimple::GetDataHere(format, pBuf)); }
 384 };
 385
 386 // ----------------------------------------------------------------------------
 387 // wxCustomDataObject contains arbitrary untyped user data.
 388 //
 389 // It is understood that this data can be copied bitwise.
 390 // ----------------------------------------------------------------------------
 391
 392 class WXDLLEXPORT wxCustomDataObject : public wxDataObjectSimple
 393 {
 394 public:
 395     // if you don't specify the format in the ctor, you can still use
 396     // SetFormat() later
 397     wxCustomDataObject(const wxDataFormat& format = wxFormatInvalid);
 398
 399     // the dtor calls Free()
 400     virtual ~wxCustomDataObject();
 401
 402     // you can call SetData() to set m_data: it will make a copy of the data
 403     // you pass - or you can use TakeData() which won't copy anything, but
 404     // will take ownership of data (i.e. will call Free() on it later)
 405     void TakeData(size_t size, void *data);
 406
 407     // this function is called to allocate "size" bytes of memory from
 408     // SetData(). The default version uses operator new[].
 409     virtual void *Alloc(size_t size);
 410
 411     // this function is called when the data is freed, you may override it to
 412     // anything you want (or may be nothing at all). The default version calls
 413     // operator delete[] on m_data
 414     virtual void Free();
 415
 416     // get data: you may override these functions if you wish to provide data
 417     // only when it's requested
 418     virtual size_t GetSize() const { return m_size; }
 419     virtual void *GetData() const { return m_data; }
 420
 421     // implement base class pure virtuals
 422     // ----------------------------------
 423     virtual size_t GetDataSize() const;
 424     virtual bool GetDataHere(void *buf) const;
 425     virtual bool SetData(size_t size, const void *buf);
 426
 427 private:
 428     size_t m_size;
 429     void  *m_data;
 430
 431     // virtual function hiding supression
 432     size_t GetDataSize(const wxDataFormat& format) const
 433         { return(wxDataObjectSimple::GetDataSize(format)); }
 434     bool GetDataHere(const wxDataFormat& format, void* pBuf) const
 435         { return(wxDataObjectSimple::GetDataHere(format, pBuf)); }
 436     bool SetData(const wxDataFormat& format, size_t nLen, const void* pBuf)
 437         { return(wxDataObjectSimple::SetData(format, nLen, pBuf)); }
 438 };
 439
 440 // ----------------------------------------------------------------------------
 441 // include platform-specific declarations of wxXXXBase classes
 442 // ----------------------------------------------------------------------------
 443
 444 #if defined(__WXMSW__)
 445     #include "wx/msw/ole/dataobj2.h"
 446
 447     // wxURLDataObject defined in msw/ole/dataobj2.h
 448 #else // !__WXMSW__
 449     #if defined(__WXGTK__)
 450         #include "wx/gtk/dataobj2.h"
 451     #elif defined(__WXMAC__)
 452         #include "wx/mac/dataobj2.h"
 453     #elif defined(__WXPM__)
 454         #include "wx/os2/dataobj2.h"
 455     #endif
 456
 457     // wxURLDataObject is simply wxTextDataObject with a different name
 458     class WXDLLEXPORT wxURLDataObject : public wxTextDataObject
 459     {
 460     public:
 461         wxString GetURL() const { return GetText(); }
 462     };
 463 #endif // __WXMSW__/!__WXMSW__
 464
 465 #endif // _WX_DATAOBJ_H_BASE_