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