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(__WXQT__)
 165     #include "wx/qt/dnd.h"
 166 #elif defined(__WXMAC__)
 167     #include "wx/mac/dataobj.h"
 168 #elif defined(__WXPM__)
 169     #include "wx/os2/dataobj.h"
 170 #elif defined(__WXSTUBS__)
 171     #include "wx/stubs/dnd.h"
 172 #endif
 173
 174 // ----------------------------------------------------------------------------
 175 // wxDataObjectSimple is a wxDataObject which only supports one format (in
 176 // both Get and Set directions, but you may return FALSE from GetDataHere() or
 177 // SetData() if one of them is not supported). This is the simplest possible
 178 // wxDataObject implementation.
 179 //
 180 // This is still an "abstract base class" (although it doesn't have any pure
 181 // virtual functions), to use it you should derive from it and implement
 182 // GetDataSize(), GetDataHere() and SetData() functions because the base class
 183 // versions don't do anything - they just return "not implemented".
 184 //
 185 // This class should be used when you provide data in only one format (no
 186 // conversion to/from other formats), either a standard or a custom one.
 187 // Otherwise, you should use wxDataObjectComposite or wxDataObject directly.
 188 // ----------------------------------------------------------------------------
 189
 190 class WXDLLEXPORT wxDataObjectSimple : public wxDataObject
 191 {
 192 public:
 193     // ctor takes the format we support, but it can also be set later with
 194     // SetFormat()
 195     wxDataObjectSimple(const wxDataFormat& format = wxFormatInvalid)
 196         : m_format(format)
 197         {
 198         }
 199
 200     // get/set the format we support
 201     const wxDataFormat& GetFormat() const { return m_format; }
 202     void SetFormat(const wxDataFormat& format) { m_format = format; }
 203
 204     // virtual functions to override in derived class (the base class versions
 205     // just return "not implemented")
 206     // -----------------------------------------------------------------------
 207
 208     // get the size of our data
 209     virtual size_t GetDataSize() const
 210         { return 0; }
 211
 212     // copy our data to the buffer
 213     virtual bool GetDataHere(void *WXUNUSED(buf)) const
 214         { return FALSE; }
 215
 216     // copy data from buffer to our data
 217     virtual bool SetData(size_t WXUNUSED(len), const void *WXUNUSED(buf))
 218         { return FALSE; }
 219
 220     // implement base class pure virtuals
 221     // ----------------------------------
 222     virtual wxDataFormat GetPreferredFormat(wxDataObjectBase::Direction WXUNUSED(dir) = Get) const
 223         { return m_format; }
 224     virtual size_t GetFormatCount(wxDataObjectBase::Direction WXUNUSED(dir) = Get) const
 225         { return 1; }
 226     virtual void GetAllFormats(wxDataFormat *formats,
 227                                wxDataObjectBase::Direction WXUNUSED(dir) = Get) const
 228         { *formats = m_format; }
 229     virtual size_t GetDataSize(const wxDataFormat& WXUNUSED(format)) const
 230         { return GetDataSize(); }
 231     virtual bool GetDataHere(const wxDataFormat& WXUNUSED(format),
 232                              void *buf) const
 233         { return GetDataHere(buf); }
 234     virtual bool SetData(const wxDataFormat& WXUNUSED(format),
 235                          size_t len, const void *buf)
 236         { return SetData(len, buf); }
 237
 238 private:
 239     // the one and only format we support
 240     wxDataFormat m_format;
 241 };
 242
 243 // ----------------------------------------------------------------------------
 244 // wxDataObjectComposite is the simplest way to implement wxDataObject
 245 // supporting multiple formats. It contains several wxDataObjectSimple and
 246 // supports all formats supported by any of them.
 247 //
 248 // This class shouldn't be (normally) derived from, but may be used directly.
 249 // If you need more flexibility than what it provides, you should probably use
 250 // wxDataObject directly.
 251 // ----------------------------------------------------------------------------
 252
 253 WX_DECLARE_LIST(wxDataObjectSimple, wxSimpleDataObjectList);
 254
 255 class WXDLLEXPORT wxDataObjectComposite : public wxDataObject
 256 {
 257 public:
 258     // ctor
 259     wxDataObjectComposite() { m_preferred = 0; }
 260
 261     // add data object (it will be deleted by wxDataObjectComposite, hence it
 262     // must be allocated on the heap) whose format will become the preferred
 263     // one if preferred == TRUE
 264     void Add(wxDataObjectSimple *dataObject, bool preferred = FALSE);
 265
 266     // implement base class pure virtuals
 267     // ----------------------------------
 268     virtual wxDataFormat GetPreferredFormat(wxDataObjectBase::Direction dir = Get) const;
 269     virtual size_t GetFormatCount(wxDataObjectBase::Direction dir = Get) const;
 270     virtual void GetAllFormats(wxDataFormat *formats, wxDataObjectBase::Direction dir = Get) const;
 271     virtual size_t GetDataSize(const wxDataFormat& format) const;
 272     virtual bool GetDataHere(const wxDataFormat& format, void *buf) const;
 273     virtual bool SetData(const wxDataFormat& format, size_t len, const void *buf);
 274
 275 protected:
 276     // returns the pointer to the object which supports this format or NULL
 277     wxDataObjectSimple *GetObject(const wxDataFormat& format) const;
 278
 279 private:
 280     // the list of all (simple) data objects whose formats we support
 281     wxSimpleDataObjectList m_dataObjects;
 282
 283     // the index of the preferred one (0 initially, so by default the first
 284     // one is the preferred)
 285     size_t m_preferred;
 286 };
 287
 288 // ============================================================================
 289 // Standard implementations of wxDataObjectSimple which can be used directly
 290 // (i.e. without having to derive from them) for standard data type transfers.
 291 //
 292 // Note that although all of them can work with provided data, you can also
 293 // override their virtual GetXXX() functions to only provide data on demand.
 294 // ============================================================================
 295
 296 // ----------------------------------------------------------------------------
 297 // wxTextDataObject contains text data
 298 // ----------------------------------------------------------------------------
 299
 300 class WXDLLEXPORT wxTextDataObject : public wxDataObjectSimple
 301 {
 302 public:
 303     // ctor: you can specify the text here or in SetText(), or override
 304     // GetText()
 305     wxTextDataObject(const wxString& text = wxEmptyString)
 306         : wxDataObjectSimple(wxDF_TEXT), m_text(text)
 307         {
 308         }
 309
 310     // virtual functions which you may override if you want to provide text on
 311     // demand only - otherwise, the trivial default versions will be used
 312     virtual size_t GetTextLength() const { return m_text.Len() + 1; }
 313     virtual wxString GetText() const { return m_text; }
 314     virtual void SetText(const wxString& text) { m_text = text; }
 315
 316     // implement base class pure virtuals
 317     // ----------------------------------
 318     virtual size_t GetDataSize() const;
 319     virtual bool GetDataHere(void *buf) const;
 320     virtual bool SetData(size_t len, const void *buf);
 321
 322 private:
 323     wxString m_text;
 324
 325     // virtual function hiding supression
 326     size_t GetDataSize(const wxDataFormat& format) const
 327         { return(wxDataObjectSimple::GetDataSize(format)); }
 328     bool GetDataHere(const wxDataFormat& format, void *pBuf) const
 329         { return(wxDataObjectSimple::GetDataHere(format, pBuf)); }
 330     bool SetData(const wxDataFormat& format, size_t nLen, const void* pBuf)
 331         { return(wxDataObjectSimple::SetData(format, nLen, pBuf)); }
 332 };
 333
 334 // ----------------------------------------------------------------------------
 335 // wxBitmapDataObject contains a bitmap
 336 // ----------------------------------------------------------------------------
 337
 338 class WXDLLEXPORT wxBitmapDataObjectBase : public wxDataObjectSimple
 339 {
 340 public:
 341     // ctor: you can specify the bitmap here or in SetBitmap(), or override
 342     // GetBitmap()
 343     wxBitmapDataObjectBase(const wxBitmap& bitmap = wxNullBitmap)
 344         : wxDataObjectSimple(wxDF_BITMAP), m_bitmap(bitmap)
 345         {
 346         }
 347
 348     // virtual functions which you may override if you want to provide data on
 349     // demand only - otherwise, the trivial default versions will be used
 350     virtual wxBitmap GetBitmap() const { return m_bitmap; }
 351     virtual void SetBitmap(const wxBitmap& bitmap) { m_bitmap = bitmap; }
 352
 353 protected:
 354     wxBitmap m_bitmap;
 355 };
 356
 357 // ----------------------------------------------------------------------------
 358 // wxFileDataObject contains a list of filenames
 359 //
 360 // NB: notice that this is a "write only" object, it can only be filled with
 361 //     data from drag and drop operation.
 362 // ----------------------------------------------------------------------------
 363
 364 class WXDLLEXPORT wxFileDataObjectBase : public wxDataObjectSimple
 365 {
 366 public:
 367     // ctor: use AddFile() later to fill the array
 368     wxFileDataObjectBase() : wxDataObjectSimple(wxDF_FILENAME) { }
 369
 370     // get a reference to our array
 371     const wxArrayString& GetFilenames() const { return m_filenames; }
 372
 373     // the Get() functions do nothing for us
 374     virtual size_t GetDataSize() const { return 0; }
 375     virtual bool GetDataHere(void *WXUNUSED(buf)) const { return FALSE; }
 376
 377 protected:
 378     wxArrayString m_filenames;
 379
 380 private:
 381     // Virtual function hiding supression
 382     size_t GetDataSize(const wxDataFormat& format) const
 383         { return(wxDataObjectSimple::GetDataSize(format)); }
 384     bool GetDataHere(const wxDataFormat& format, void* pBuf) const
 385         { return(wxDataObjectSimple::GetDataHere(format, pBuf)); }
 386 };
 387
 388 // ----------------------------------------------------------------------------
 389 // wxCustomDataObject contains arbitrary untyped user data.
 390 //
 391 // It is understood that this data can be copied bitwise.
 392 // ----------------------------------------------------------------------------
 393
 394 class WXDLLEXPORT wxCustomDataObject : public wxDataObjectSimple
 395 {
 396 public:
 397     // if you don't specify the format in the ctor, you can still use
 398     // SetFormat() later
 399     wxCustomDataObject(const wxDataFormat& format = wxFormatInvalid);
 400
 401     // the dtor calls Free()
 402     virtual ~wxCustomDataObject();
 403
 404     // you can call SetData() to set m_data: it will make a copy of the data
 405     // you pass - or you can use TakeData() which won't copy anything, but
 406     // will take ownership of data (i.e. will call Free() on it later)
 407     void TakeData(size_t size, void *data);
 408
 409     // this function is called to allocate "size" bytes of memory from
 410     // SetData(). The default version uses operator new[].
 411     virtual void *Alloc(size_t size);
 412
 413     // this function is called when the data is freed, you may override it to
 414     // anything you want (or may be nothing at all). The default version calls
 415     // operator delete[] on m_data
 416     virtual void Free();
 417
 418     // get data: you may override these functions if you wish to provide data
 419     // only when it's requested
 420     virtual size_t GetSize() const { return m_size; }
 421     virtual void *GetData() const { return m_data; }
 422
 423     // implement base class pure virtuals
 424     // ----------------------------------
 425     virtual size_t GetDataSize() const;
 426     virtual bool GetDataHere(void *buf) const;
 427     virtual bool SetData(size_t size, const void *buf);
 428
 429 private:
 430     size_t m_size;
 431     void  *m_data;
 432
 433     // virtual function hiding supression
 434     size_t GetDataSize(const wxDataFormat& format) const
 435         { return(wxDataObjectSimple::GetDataSize(format)); }
 436     bool GetDataHere(const wxDataFormat& format, void* pBuf) const
 437         { return(wxDataObjectSimple::GetDataHere(format, pBuf)); }
 438     bool SetData(const wxDataFormat& format, size_t nLen, const void* pBuf)
 439         { return(wxDataObjectSimple::SetData(format, nLen, pBuf)); }
 440 };
 441
 442 // ----------------------------------------------------------------------------
 443 // include platform-specific declarations of wxXXXBase classes
 444 // ----------------------------------------------------------------------------
 445
 446 #if defined(__WXMSW__)
 447     #include "wx/msw/ole/dataobj2.h"
 448 #elif defined(__WXMOTIF__)
 449     // #include "wx/motif/dataobj2.h" -- not yet
 450 #elif defined(__WXGTK__)
 451     #include "wx/gtk/dataobj2.h"
 452 #elif defined(__WXMAC__)
 453     #include "wx/mac/dataobj2.h"
 454 #elif defined(__WXPM__)
 455     #include "wx/os2/dataobj2.h"
 456 #endif
 457
 458 #endif // _WX_DATAOBJ_H_BASE_