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