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 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
 151 // ----------------------------------------------------------------------------
 152 // include the platform-specific declarations of wxDataObject
 153 // ----------------------------------------------------------------------------
 154
 155 #if defined(__WXMSW__)
 156     #include "wx/msw/ole/dataobj.h"
 157 #elif defined(__WXMOTIF__)
 158     #include "wx/motif/dataobj.h"
 159 #elif defined(__WXGTK__)
 160     #include "wx/gtk/dataobj.h"
 161 #elif defined(__WXQT__)
 162     #include "wx/qt/dnd.h"
 163 #elif defined(__WXMAC__)
 164     #include "wx/mac/dataobj.h"
 165 #elif defined(__WXPM__)
 166     #include "wx/os2/dataobj.h"
 167 #elif defined(__WXSTUBS__)
 168     #include "wx/stubs/dnd.h"
 169 #endif
 170
 171 // ----------------------------------------------------------------------------
 172 // wxDataObjectSimple is a wxDataObject which only supports one format (in
 173 // both Get and Set directions, but you may return FALSE from GetDataHere() or
 174 // SetData() if one of them is not supported). This is the simplest possible
 175 // wxDataObject implementation.
 176 //
 177 // This is still an "abstract base class" (although it doesn't have any pure
 178 // virtual functions), to use it you should derive from it and implement
 179 // GetDataSize(), GetDataHere() and SetData() functions because the base class
 180 // versions don't do anything - they just return "not implemented".
 181 //
 182 // This class should be used when you provide data in only one format (no
 183 // conversion to/from other formats), either a standard or a custom one.
 184 // Otherwise, you should use wxDataObjectComposite or wxDataObject directly.
 185 // ----------------------------------------------------------------------------
 186
 187 class WXDLLEXPORT wxDataObjectSimple : public wxDataObject
 188 {
 189 public:
 190     // ctor takes the format we support, but it can also be set later with
 191     // SetFormat()
 192     wxDataObjectSimple(const wxDataFormat& format = wxFormatInvalid)
 193         : m_format(format)
 194         {
 195         }
 196
 197     // get/set the format we support
 198     const wxDataFormat& GetFormat() const { return m_format; }
 199     void SetFormat(const wxDataFormat& format) { m_format = format; }
 200
 201     // virtual functions to override in derived class (the base class versions
 202     // just return "not implemented")
 203     // -----------------------------------------------------------------------
 204
 205     // get the size of our data
 206     virtual size_t GetDataSize() const
 207         { return 0; }
 208
 209     // copy our data to the buffer
 210     virtual bool GetDataHere(void *WXUNUSED(buf)) const
 211         { return FALSE; }
 212
 213     // copy data from buffer to our data
 214     virtual bool SetData(size_t WXUNUSED(len), const void *WXUNUSED(buf))
 215         { return FALSE; }
 216
 217     // implement base class pure virtuals
 218     // ----------------------------------
 219     virtual wxDataFormat GetPreferredFormat(wxDataObjectBase::Direction WXUNUSED(dir) = Get) const
 220         { return m_format; }
 221     virtual size_t GetFormatCount(wxDataObjectBase::Direction WXUNUSED(dir) = Get) const
 222         { return 1; }
 223     virtual void GetAllFormats(wxDataFormat *formats,
 224                                wxDataObjectBase::Direction WXUNUSED(dir) = Get) const
 225         { *formats = m_format; }
 226     virtual size_t GetDataSize(const wxDataFormat& WXUNUSED(format)) const
 227         { return GetDataSize(); }
 228     virtual bool GetDataHere(const wxDataFormat& WXUNUSED(format),
 229                              void *buf) const
 230         { return GetDataHere(buf); }
 231     virtual bool SetData(const wxDataFormat& WXUNUSED(format),
 232                          size_t len, const void *buf)
 233         { return SetData(len, buf); }
 234
 235 private:
 236     // the one and only format we support
 237     wxDataFormat m_format;
 238 };
 239
 240 // ----------------------------------------------------------------------------
 241 // wxDataObjectComposite is the simplest way to implement wxDataObject
 242 // supporting multiple formats. It contains several wxDataObjectSimple and
 243 // supports all formats supported by any of them.
 244 //
 245 // This class shouldn't be (normally) derived from, but may be used directly.
 246 // If you need more flexibility than what it provides, you should probably use
 247 // wxDataObject directly.
 248 // ----------------------------------------------------------------------------
 249
 250 WX_DECLARE_LIST(wxDataObjectSimple, wxSimpleDataObjectList);
 251
 252 class WXDLLEXPORT wxDataObjectComposite : public wxDataObject
 253 {
 254 public:
 255     // ctor
 256     wxDataObjectComposite() { m_preferred = 0; }
 257
 258     // add data object (it will be deleted by wxDataObjectComposite, hence it
 259     // must be allocated on the heap) whose format will become the preferred
 260     // one if preferred == TRUE
 261     void Add(wxDataObjectSimple *dataObject, bool preferred = FALSE);
 262
 263     // implement base class pure virtuals
 264     // ----------------------------------
 265     virtual wxDataFormat GetPreferredFormat(wxDataObjectBase::Direction dir = Get) const;
 266     virtual size_t GetFormatCount(wxDataObjectBase::Direction dir = Get) const;
 267     virtual void GetAllFormats(wxDataFormat *formats, wxDataObjectBase::Direction dir = Get) const;
 268     virtual size_t GetDataSize(const wxDataFormat& format) const;
 269     virtual bool GetDataHere(const wxDataFormat& format, void *buf) const;
 270     virtual bool SetData(const wxDataFormat& format, size_t len, const void *buf);
 271
 272 protected:
 273     // returns the pointer to the object which supports this format or NULL
 274     wxDataObjectSimple *GetObject(const wxDataFormat& format) const;
 275
 276 private:
 277     // the list of all (simple) data objects whose formats we support
 278     wxSimpleDataObjectList m_dataObjects;
 279
 280     // the index of the preferred one (0 initially, so by default the first
 281     // one is the preferred)
 282     size_t m_preferred;
 283 };
 284
 285 // ============================================================================
 286 // Standard implementations of wxDataObjectSimple which can be used directly
 287 // (i.e. without having to derive from them) for standard data type transfers.
 288 //
 289 // Note that although all of them can work with provided data, you can also
 290 // override their virtual GetXXX() functions to only provide data on demand.
 291 // ============================================================================
 292
 293 // ----------------------------------------------------------------------------
 294 // wxTextDataObject contains text data
 295 // ----------------------------------------------------------------------------
 296
 297 class WXDLLEXPORT wxTextDataObject : public wxDataObjectSimple
 298 {
 299 public:
 300     // ctor: you can specify the text here or in SetText(), or override
 301     // GetText()
 302     wxTextDataObject(const wxString& text = wxEmptyString)
 303         : wxDataObjectSimple(wxDF_TEXT), m_text(text)
 304         {
 305         }
 306
 307     // virtual functions which you may override if you want to provide text on
 308     // demand only - otherwise, the trivial default versions will be used
 309     virtual size_t GetTextLength() const { return m_text.Len() + 1; }
 310     virtual wxString GetText() const { return m_text; }
 311     virtual void SetText(const wxString& text) { m_text = text; }
 312
 313     // implement base class pure virtuals
 314     // ----------------------------------
 315     virtual size_t GetDataSize() const;
 316     virtual bool GetDataHere(void *buf) const;
 317     virtual bool SetData(size_t len, const void *buf);
 318
 319 private:
 320     wxString m_text;
 321
 322     // virtual function hiding supression
 323     size_t GetDataSize(const wxDataFormat& format) const
 324         { return(wxDataObjectSimple::GetDataSize(format)); }
 325     bool GetDataHere(const wxDataFormat& format, void *pBuf) const
 326         { return(wxDataObjectSimple::GetDataHere(format, pBuf)); }
 327     bool SetData(const wxDataFormat& format, size_t nLen, const void* pBuf)
 328         { return(wxDataObjectSimple::SetData(format, nLen, pBuf)); }
 329 };
 330
 331 // ----------------------------------------------------------------------------
 332 // wxBitmapDataObject contains a bitmap
 333 // ----------------------------------------------------------------------------
 334
 335 class WXDLLEXPORT wxBitmapDataObjectBase : public wxDataObjectSimple
 336 {
 337 public:
 338     // ctor: you can specify the bitmap here or in SetBitmap(), or override
 339     // GetBitmap()
 340     wxBitmapDataObjectBase(const wxBitmap& bitmap = wxNullBitmap)
 341         : wxDataObjectSimple(wxDF_BITMAP), m_bitmap(bitmap)
 342         {
 343         }
 344
 345     // virtual functions which you may override if you want to provide data on
 346     // demand only - otherwise, the trivial default versions will be used
 347     virtual wxBitmap GetBitmap() const { return m_bitmap; }
 348     virtual void SetBitmap(const wxBitmap& bitmap) { m_bitmap = bitmap; }
 349
 350 protected:
 351     wxBitmap m_bitmap;
 352 };
 353
 354 // ----------------------------------------------------------------------------
 355 // wxFileDataObject contains a list of filenames
 356 //
 357 // NB: notice that this is a "write only" object, it can only be filled with
 358 //     data from drag and drop operation.
 359 // ----------------------------------------------------------------------------
 360
 361 class WXDLLEXPORT wxFileDataObjectBase : public wxDataObjectSimple
 362 {
 363 public:
 364     // ctor: use AddFile() later to fill the array
 365     wxFileDataObjectBase() : wxDataObjectSimple(wxDF_FILENAME) { }
 366
 367     // get a reference to our array
 368     const wxArrayString& GetFilenames() const { return m_filenames; }
 369
 370     // the Get() functions do nothing for us
 371     virtual size_t GetDataSize() const { return 0; }
 372     virtual bool GetDataHere(void *WXUNUSED(buf)) const { return FALSE; }
 373
 374 protected:
 375     wxArrayString m_filenames;
 376
 377 private:
 378     // Virtual function hiding supression
 379     size_t GetDataSize(const wxDataFormat& format) const
 380         { return(wxDataObjectSimple::GetDataSize(format)); }
 381     bool GetDataHere(const wxDataFormat& format, void* pBuf) const
 382         { return(wxDataObjectSimple::GetDataHere(format, pBuf)); }
 383 };
 384
 385 // ----------------------------------------------------------------------------
 386 // wxCustomDataObject contains arbitrary untyped user data.
 387 //
 388 // It is understood that this data can be copied bitwise.
 389 // ----------------------------------------------------------------------------
 390
 391 class WXDLLEXPORT wxCustomDataObject : public wxDataObjectSimple
 392 {
 393 public:
 394     // if you don't specify the format in the ctor, you can still use
 395     // SetFormat() later
 396     wxCustomDataObject(const wxDataFormat& format = wxFormatInvalid);
 397
 398     // the dtor calls Free()
 399     virtual ~wxCustomDataObject();
 400
 401     // you can call SetData() to set m_data: it will make a copy of the data
 402     // you pass - or you can use TakeData() which won't copy anything, but
 403     // will take ownership of data (i.e. will call Free() on it later)
 404     void TakeData(size_t size, void *data);
 405
 406     // this function is called to allocate "size" bytes of memory from
 407     // SetData(). The default version uses operator new[].
 408     virtual void *Alloc(size_t size);
 409
 410     // this function is called when the data is freed, you may override it to
 411     // anything you want (or may be nothing at all). The default version calls
 412     // operator delete[] on m_data
 413     virtual void Free();
 414
 415     // get data: you may override these functions if you wish to provide data
 416     // only when it's requested
 417     virtual size_t GetSize() const { return m_size; }
 418     virtual void *GetData() const { return m_data; }
 419
 420     // implement base class pure virtuals
 421     // ----------------------------------
 422     virtual size_t GetDataSize() const;
 423     virtual bool GetDataHere(void *buf) const;
 424     virtual bool SetData(size_t size, const void *buf);
 425
 426 private:
 427     size_t m_size;
 428     void  *m_data;
 429
 430     // virtual function hiding supression
 431     size_t GetDataSize(const wxDataFormat& format) const
 432         { return(wxDataObjectSimple::GetDataSize(format)); }
 433     bool GetDataHere(const wxDataFormat& format, void* pBuf) const
 434         { return(wxDataObjectSimple::GetDataHere(format, pBuf)); }
 435     bool SetData(const wxDataFormat& format, size_t nLen, const void* pBuf)
 436         { return(wxDataObjectSimple::SetData(format, nLen, pBuf)); }
 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(__WXMAC__)
 450     #include "wx/mac/dataobj2.h"
 451 #elif defined(__WXPM__)
 452     #include "wx/os2/dataobj2.h"
 453 #endif
 454
 455 #endif // _WX_DATAOBJ_H_BASE_