src/gtk/clipbrd.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/gtk/clipbrd.cpp
   3 // Purpose:     wxClipboard implementation for wxGTK
   4 // Author:      Robert Roebling, Vadim Zeitlin
   5 // Id:          $Id$
   6 // Copyright:   (c) 1998 Robert Roebling
   7 //              (c) 2007 Vadim Zeitlin
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 // ============================================================================
  12 // declarations
  13 // ============================================================================
  14
  15 // ----------------------------------------------------------------------------
  16 // headers
  17 // ----------------------------------------------------------------------------
  18
  19 // For compilers that support precompilation, includes "wx.h".
  20 #include "wx/wxprec.h"
  21
  22 #if wxUSE_CLIPBOARD
  23
  24 #include "wx/clipbrd.h"
  25
  26 #ifndef WX_PRECOMP
  27     #include "wx/log.h"
  28     #include "wx/utils.h"
  29     #include "wx/dataobj.h"
  30 #endif
  31
  32 #include "wx/ptr_scpd.h"
  33 #include "wx/scopeguard.h"
  34
  35 #include "wx/gtk/private.h"
  36
  37 wxDECLARE_SCOPED_ARRAY(wxDataFormat, wxDataFormatArray)
  38 wxDEFINE_SCOPED_ARRAY(wxDataFormat, wxDataFormatArray)
  39
  40 // ----------------------------------------------------------------------------
  41 // data
  42 // ----------------------------------------------------------------------------
  43
  44 static GdkAtom  g_clipboardAtom   = 0;
  45 static GdkAtom  g_targetsAtom     = 0;
  46 static GdkAtom  g_timestampAtom   = 0;
  47
  48 #if wxUSE_UNICODE
  49 extern GdkAtom g_altTextAtom;
  50 #endif
  51
  52 // the trace mask we use with wxLogTrace() - call
  53 // wxLog::AddTraceMask(TRACE_CLIPBOARD) to enable the trace messages from here
  54 // (there will be a *lot* of them!)
  55 #define TRACE_CLIPBOARD _T("clipboard")
  56
  57 // ----------------------------------------------------------------------------
  58 // wxClipboardSync: used to perform clipboard operations synchronously
  59 // ----------------------------------------------------------------------------
  60
  61 // constructing this object on stack will wait wait until the latest clipboard
  62 // operation is finished on block exit
  63 //
  64 // notice that there can be no more than one such object alive at any moment,
  65 // i.e. reentrancies are not allowed
  66 class wxClipboardSync
  67 {
  68 public:
  69     wxClipboardSync(wxClipboard& clipboard)
  70     {
  71         wxASSERT_MSG( !ms_clipboard, _T("reentrancy in clipboard code") );
  72         ms_clipboard = &clipboard;
  73     }
  74
  75     ~wxClipboardSync()
  76     {
  77         while ( ms_clipboard )
  78             gtk_main_iteration();
  79     }
  80
  81     // this method must be called by GTK+ callbacks to indicate that we got the
  82     // result for our clipboard operation
  83     static void OnDone(wxClipboard * WXUNUSED_UNLESS_DEBUG(clipboard))
  84     {
  85         wxASSERT_MSG( clipboard == ms_clipboard,
  86                         _T("got notification for alien clipboard") );
  87
  88         ms_clipboard = NULL;
  89     }
  90
  91     // this method should be called if it's possible that no async clipboard
  92     // operation is currently in progress (like it can be the case when the
  93     // clipboard is cleared but not because we asked about it), it should only
  94     // be called if such situation is expected -- otherwise call OnDone() which
  95     // would assert in this case
  96     static void OnDoneIfInProgress(wxClipboard *clipboard)
  97     {
  98         if ( ms_clipboard )
  99             OnDone(clipboard);
 100     }
 101
 102 private:
 103     static wxClipboard *ms_clipboard;
 104
 105     DECLARE_NO_COPY_CLASS(wxClipboardSync)
 106 };
 107
 108 wxClipboard *wxClipboardSync::ms_clipboard = NULL;
 109
 110 // ============================================================================
 111 // clipboard callbacks implementation
 112 // ============================================================================
 113
 114 //-----------------------------------------------------------------------------
 115 // "selection_received" for targets
 116 //-----------------------------------------------------------------------------
 117
 118 extern "C" {
 119 static void
 120 targets_selection_received( GtkWidget *WXUNUSED(widget),
 121                             GtkSelectionData *selection_data,
 122                             guint32 WXUNUSED(time),
 123                             wxClipboard *clipboard )
 124 {
 125     if ( !clipboard )
 126         return;
 127
 128     wxON_BLOCK_EXIT1(wxClipboardSync::OnDone, clipboard);
 129
 130     if ( !selection_data || selection_data->length <= 0 )
 131         return;
 132
 133     // make sure we got the data in the correct form
 134     GdkAtom type = selection_data->type;
 135     if ( type != GDK_SELECTION_TYPE_ATOM )
 136     {
 137         if ( strcmp(wxGtkString(gdk_atom_name(type)), "TARGETS") != 0 )
 138         {
 139             wxLogTrace( TRACE_CLIPBOARD,
 140                         _T("got unsupported clipboard target") );
 141
 142             return;
 143         }
 144     }
 145
 146 #ifdef __WXDEBUG__
 147     // it's not really a format, of course, but we can reuse its GetId() method
 148     // to format this atom as string
 149     wxDataFormat clip(selection_data->selection);
 150     wxLogTrace( TRACE_CLIPBOARD,
 151                 wxT("Received available formats for clipboard %s"),
 152                 clip.GetId().c_str() );
 153 #endif // __WXDEBUG__
 154
 155     // the atoms we received, holding a list of targets (= formats)
 156     const GdkAtom * const atoms = (GdkAtom *)selection_data->data;
 157     for ( size_t i = 0; i < selection_data->length/sizeof(GdkAtom); i++ )
 158     {
 159         const wxDataFormat format(atoms[i]);
 160
 161         wxLogTrace(TRACE_CLIPBOARD, wxT("\t%s"), format.GetId().c_str());
 162
 163         if ( clipboard->GTKOnTargetReceived(format) )
 164             return;
 165     }
 166 }
 167 }
 168
 169 bool wxClipboard::GTKOnTargetReceived(const wxDataFormat& format)
 170 {
 171     if ( format != m_targetRequested )
 172         return false;
 173
 174     m_formatSupported = true;
 175     return true;
 176 }
 177
 178 //-----------------------------------------------------------------------------
 179 // "selection_received" for the actual data
 180 //-----------------------------------------------------------------------------
 181
 182 extern "C" {
 183 static void
 184 selection_received( GtkWidget *WXUNUSED(widget),
 185                     GtkSelectionData *selection_data,
 186                     guint32 WXUNUSED(time),
 187                     wxClipboard *clipboard )
 188 {
 189     if ( !clipboard )
 190         return;
 191
 192     wxON_BLOCK_EXIT1(wxClipboardSync::OnDone, clipboard);
 193
 194     if ( !selection_data || selection_data->length <= 0 )
 195         return;
 196
 197     clipboard->GTKOnSelectionReceived(*selection_data);
 198 }
 199 }
 200
 201 //-----------------------------------------------------------------------------
 202 // "selection_clear"
 203 //-----------------------------------------------------------------------------
 204
 205 extern "C" {
 206 static gint
 207 selection_clear_clip( GtkWidget *WXUNUSED(widget), GdkEventSelection *event )
 208 {
 209     wxClipboard * const clipboard = wxTheClipboard;
 210     if ( !clipboard )
 211         return TRUE;
 212
 213     // notice the use of OnDoneIfInProgress() here instead of just OnDone():
 214     // it's perfectly possible that we're receiving this notification from GTK+
 215     // even though we hadn't cleared the clipboard ourselves but because
 216     // another application (or even another window in the same program)
 217     // acquired it
 218     wxON_BLOCK_EXIT1(wxClipboardSync::OnDoneIfInProgress, clipboard);
 219
 220     wxClipboard::Kind kind;
 221     if (event->selection == GDK_SELECTION_PRIMARY)
 222     {
 223         wxLogTrace(TRACE_CLIPBOARD, wxT("Lost primary selection" ));
 224
 225         kind = wxClipboard::Primary;
 226     }
 227     else if (event->selection == g_clipboardAtom)
 228     {
 229         wxLogTrace(TRACE_CLIPBOARD, wxT("Lost clipboard" ));
 230
 231         kind = wxClipboard::Clipboard;
 232     }
 233     else // some other selection, we're not concerned
 234     {
 235         return FALSE;
 236     }
 237
 238     // the clipboard is no longer in our hands, we don't need data any more
 239     clipboard->GTKClearData(kind);
 240
 241     return TRUE;
 242 }
 243 }
 244
 245 //-----------------------------------------------------------------------------
 246 // selection handler for supplying data
 247 //-----------------------------------------------------------------------------
 248
 249 extern "C" {
 250 static void
 251 selection_handler( GtkWidget *WXUNUSED(widget),
 252                    GtkSelectionData *selection_data,
 253                    guint WXUNUSED(info),
 254                    guint WXUNUSED(time),
 255                    gpointer signal_data )
 256 {
 257     wxClipboard * const clipboard = wxTheClipboard;
 258     if ( !clipboard )
 259         return;
 260
 261     wxDataObject * const data = clipboard->GTKGetDataObject();
 262     if ( !data )
 263         return;
 264
 265     // ICCCM says that TIMESTAMP is a required atom.
 266     // In particular, it satisfies Klipper, which polls
 267     // TIMESTAMP to see if the clipboards content has changed.
 268     // It shall return the time which was used to set the data.
 269     if (selection_data->target == g_timestampAtom)
 270     {
 271         guint timestamp = GPOINTER_TO_UINT (signal_data);
 272         gtk_selection_data_set(selection_data,
 273                                GDK_SELECTION_TYPE_INTEGER,
 274                                32,
 275                                (guchar*)&(timestamp),
 276                                sizeof(timestamp));
 277         wxLogTrace(TRACE_CLIPBOARD,
 278                    _T("Clipboard TIMESTAMP requested, returning timestamp=%u"),
 279                    timestamp);
 280         return;
 281     }
 282
 283     wxDataFormat format( selection_data->target );
 284
 285 #ifdef __WXDEBUG__
 286     wxLogTrace(TRACE_CLIPBOARD,
 287                _T("clipboard data in format %s, GtkSelectionData is target=%s type=%s selection=%s timestamp=%u"),
 288                format.GetId().c_str(),
 289                wxString::FromAscii(wxGtkString(gdk_atom_name(selection_data->target))).c_str(),
 290                wxString::FromAscii(wxGtkString(gdk_atom_name(selection_data->type))).c_str(),
 291                wxString::FromAscii(wxGtkString(gdk_atom_name(selection_data->selection))).c_str(),
 292                GPOINTER_TO_UINT( signal_data )
 293                );
 294 #endif // __WXDEBUG__
 295
 296     if ( !data->IsSupportedFormat( format ) )
 297         return;
 298
 299     int size = data->GetDataSize( format );
 300     if ( !size )
 301         return;
 302
 303     wxCharBuffer buf(size - 1); // it adds 1 internally (for NUL)
 304
 305     // text data must be returned in UTF8 if format is wxDF_UNICODETEXT
 306     if ( !data->GetDataHere(format, buf.data()) )
 307         return;
 308
 309     // use UTF8_STRING format if requested in Unicode build but just plain
 310     // STRING one in ANSI or if explicitly asked in Unicode
 311 #if wxUSE_UNICODE
 312     if (format == wxDataFormat(wxDF_UNICODETEXT))
 313     {
 314         gtk_selection_data_set_text(
 315             selection_data,
 316             (const gchar*)buf.data(),
 317             size );
 318     }
 319     else
 320 #endif // wxUSE_UNICODE
 321     {
 322         gtk_selection_data_set(
 323             selection_data,
 324             GDK_SELECTION_TYPE_STRING,
 325             8*sizeof(gchar),
 326             (const guchar*)buf.data(),
 327             size );
 328     }
 329 }
 330 }
 331
 332 void wxClipboard::GTKOnSelectionReceived(const GtkSelectionData& sel)
 333 {
 334     wxCHECK_RET( m_receivedData, _T("should be inside GetData()") );
 335
 336     const wxDataFormat format(sel.target);
 337     wxLogTrace(TRACE_CLIPBOARD, _T("Received selection %s"),
 338                format.GetId().c_str());
 339
 340     if ( !m_receivedData->IsSupportedFormat(format) )
 341         return;
 342
 343     m_receivedData->SetData(format, sel.length, sel.data);
 344     m_formatSupported = true;
 345 }
 346
 347 //-----------------------------------------------------------------------------
 348 // asynchronous "selection_received" for targets
 349 //-----------------------------------------------------------------------------
 350
 351 extern "C" {
 352 static void
 353 async_targets_selection_received( GtkWidget *WXUNUSED(widget),
 354                             GtkSelectionData *selection_data,
 355                             guint32 WXUNUSED(time),
 356                             wxClipboard *clipboard )
 357 {
 358     if ( !clipboard ) // Assert?
 359         return;
 360
 361     if (!clipboard->m_sink)
 362         return;
 363
 364     wxClipboardEvent *event = new wxClipboardEvent(wxEVT_CLIPBOARD_CHANGED);
 365     event->SetEventObject( clipboard );
 366
 367     if ( !selection_data || selection_data->length <= 0 )
 368     {
 369         clipboard->m_sink->QueueEvent( event );
 370         return;
 371     }
 372
 373     // make sure we got the data in the correct form
 374     GdkAtom type = selection_data->type;
 375     if ( type != GDK_SELECTION_TYPE_ATOM )
 376     {
 377         if ( strcmp(wxGtkString(gdk_atom_name(type)), "TARGETS") != 0 )
 378         {
 379             wxLogTrace( TRACE_CLIPBOARD,
 380                         _T("got unsupported clipboard target") );
 381
 382             clipboard->m_sink->QueueEvent( event );
 383             return;
 384         }
 385     }
 386
 387 #ifdef __WXDEBUG__
 388     // it's not really a format, of course, but we can reuse its GetId() method
 389     // to format this atom as string
 390     wxDataFormat clip(selection_data->selection);
 391     wxLogTrace( TRACE_CLIPBOARD,
 392                 wxT("Received available formats for clipboard %s"),
 393                 clip.GetId().c_str() );
 394 #endif // __WXDEBUG__
 395
 396     // the atoms we received, holding a list of targets (= formats)
 397     const GdkAtom * const atoms = (GdkAtom *)selection_data->data;
 398     for ( size_t i = 0; i < selection_data->length/sizeof(GdkAtom); i++ )
 399     {
 400         const wxDataFormat format(atoms[i]);
 401
 402         wxLogTrace(TRACE_CLIPBOARD, wxT("\t%s"), format.GetId().c_str());
 403
 404         event->AddFormat( format );
 405     }
 406
 407     clipboard->m_sink->QueueEvent( event );
 408 }
 409 }
 410
 411 // ============================================================================
 412 // wxClipboard implementation
 413 // ============================================================================
 414
 415 // ----------------------------------------------------------------------------
 416 // wxClipboard ctor/dtor
 417 // ----------------------------------------------------------------------------
 418
 419 IMPLEMENT_DYNAMIC_CLASS(wxClipboard,wxObject)
 420
 421 wxClipboard::wxClipboard()
 422 {
 423     m_open = false;
 424
 425     m_dataPrimary =
 426     m_dataClipboard =
 427     m_receivedData = NULL;
 428
 429     m_formatSupported = false;
 430     m_targetRequested = 0;
 431
 432     // we use m_targetsWidget to query what formats are available
 433     m_targetsWidget = gtk_window_new( GTK_WINDOW_POPUP );
 434     gtk_widget_realize( m_targetsWidget );
 435
 436     g_signal_connect (m_targetsWidget, "selection_received",
 437                       G_CALLBACK (targets_selection_received), this);
 438
 439     // we use m_targetsWidgetAsync to query what formats asynchronously
 440     m_targetsWidgetAsync = gtk_window_new( GTK_WINDOW_POPUP );
 441     gtk_widget_realize( m_targetsWidgetAsync );
 442
 443     g_signal_connect (m_targetsWidgetAsync, "selection_received",
 444                       G_CALLBACK (async_targets_selection_received), this);
 445
 446     // we use m_clipboardWidget to get and to offer data
 447     m_clipboardWidget = gtk_window_new( GTK_WINDOW_POPUP );
 448     gtk_widget_realize( m_clipboardWidget );
 449
 450     g_signal_connect (m_clipboardWidget, "selection_received",
 451                       G_CALLBACK (selection_received), this);
 452
 453     g_signal_connect (m_clipboardWidget, "selection_clear_event",
 454                       G_CALLBACK (selection_clear_clip), NULL);
 455
 456     // initialize atoms we use if not done yet
 457     if ( !g_clipboardAtom )
 458         g_clipboardAtom = gdk_atom_intern( "CLIPBOARD", FALSE );
 459     if ( !g_targetsAtom )
 460         g_targetsAtom = gdk_atom_intern ("TARGETS", FALSE);
 461     if ( !g_timestampAtom )
 462         g_timestampAtom = gdk_atom_intern ("TIMESTAMP", FALSE);
 463 }
 464
 465 wxClipboard::~wxClipboard()
 466 {
 467     Clear();
 468
 469     gtk_widget_destroy( m_clipboardWidget );
 470     gtk_widget_destroy( m_targetsWidget );
 471 }
 472
 473 // ----------------------------------------------------------------------------
 474 // wxClipboard helper functions
 475 // ----------------------------------------------------------------------------
 476
 477 GdkAtom wxClipboard::GTKGetClipboardAtom() const
 478 {
 479     return m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
 480                         : g_clipboardAtom;
 481 }
 482
 483 void wxClipboard::GTKClearData(Kind kind)
 484 {
 485     wxDataObject *&data = Data(kind);
 486     if ( data )
 487     {
 488         delete data;
 489         data = NULL;
 490     }
 491 }
 492
 493 bool wxClipboard::SetSelectionOwner(bool set)
 494 {
 495     bool rc = gtk_selection_owner_set
 496               (
 497                 set ? m_clipboardWidget : NULL,
 498                 GTKGetClipboardAtom(),
 499                 (guint32)GDK_CURRENT_TIME
 500               );
 501
 502     if ( !rc )
 503     {
 504         wxLogTrace(TRACE_CLIPBOARD, _T("Failed to %sset selection owner"),
 505                    set ? _T("") : _T("un"));
 506     }
 507
 508     return rc;
 509 }
 510
 511 void wxClipboard::AddSupportedTarget(GdkAtom atom)
 512 {
 513     gtk_selection_add_target
 514     (
 515         m_clipboardWidget,
 516         GTKGetClipboardAtom(),
 517         atom,
 518         0 // info (same as client data) unused
 519     );
 520 }
 521
 522 bool wxClipboard::IsSupportedAsync(wxEvtHandler *sink)
 523 {
 524     m_sink = sink;
 525
 526     gtk_selection_convert( m_targetsWidgetAsync,
 527                            GTKGetClipboardAtom(),
 528                            g_targetsAtom,
 529                            (guint32) GDK_CURRENT_TIME );
 530
 531     return true;
 532 }
 533
 534 bool wxClipboard::DoIsSupported(const wxDataFormat& format)
 535 {
 536     wxCHECK_MSG( format, false, wxT("invalid clipboard format") );
 537
 538     wxLogTrace(TRACE_CLIPBOARD, wxT("Checking if format %s is available"),
 539                format.GetId().c_str());
 540
 541     // these variables will be used by our GTKOnTargetReceived()
 542     m_targetRequested = format;
 543     m_formatSupported = false;
 544
 545     // block until m_formatSupported is set from targets_selection_received
 546     // callback
 547     {
 548         wxClipboardSync sync(*this);
 549
 550         gtk_selection_convert( m_targetsWidget,
 551                                GTKGetClipboardAtom(),
 552                                g_targetsAtom,
 553                                (guint32) GDK_CURRENT_TIME );
 554     }
 555
 556     return m_formatSupported;
 557 }
 558
 559 // ----------------------------------------------------------------------------
 560 // wxClipboard public API implementation
 561 // ----------------------------------------------------------------------------
 562
 563 void wxClipboard::Clear()
 564 {
 565     if ( gdk_selection_owner_get(GTKGetClipboardAtom()) ==
 566             m_clipboardWidget->window )
 567     {
 568         wxClipboardSync sync(*this);
 569
 570         // this will result in selection_clear_clip callback being called and
 571         // it will free our data
 572         SetSelectionOwner(false);
 573     }
 574
 575     m_targetRequested = 0;
 576     m_formatSupported = false;
 577 }
 578
 579 bool wxClipboard::Open()
 580 {
 581     wxCHECK_MSG( !m_open, false, wxT("clipboard already open") );
 582
 583     m_open = true;
 584
 585     return true;
 586 }
 587
 588 bool wxClipboard::SetData( wxDataObject *data )
 589 {
 590     wxCHECK_MSG( m_open, false, wxT("clipboard not open") );
 591
 592     wxCHECK_MSG( data, false, wxT("data is invalid") );
 593
 594     Clear();
 595
 596     return AddData( data );
 597 }
 598
 599 bool wxClipboard::AddData( wxDataObject *data )
 600 {
 601     wxCHECK_MSG( m_open, false, wxT("clipboard not open") );
 602
 603     wxCHECK_MSG( data, false, wxT("data is invalid") );
 604
 605     // we can only store one wxDataObject so clear the old one
 606     Clear();
 607
 608     Data() = data;
 609
 610     // get formats from wxDataObjects
 611     const size_t count = data->GetFormatCount();
 612     wxDataFormatArray formats(new wxDataFormat[count]);
 613     data->GetAllFormats(formats.get());
 614
 615     // always provide TIMESTAMP as a target, see comments in selection_handler
 616     // for explanation
 617     AddSupportedTarget(g_timestampAtom);
 618
 619     for ( size_t i = 0; i < count; i++ )
 620     {
 621         const wxDataFormat format(formats[i]);
 622
 623         wxLogTrace(TRACE_CLIPBOARD, wxT("Adding support for %s"),
 624                    format.GetId().c_str());
 625
 626         AddSupportedTarget(format);
 627     }
 628
 629     g_signal_connect (m_clipboardWidget, "selection_get",
 630                       G_CALLBACK (selection_handler),
 631                       GUINT_TO_POINTER (gtk_get_current_event_time()) );
 632
 633     // tell the world we offer clipboard data
 634     return SetSelectionOwner();
 635 }
 636
 637 void wxClipboard::Close()
 638 {
 639     wxCHECK_RET( m_open, wxT("clipboard not open") );
 640
 641     m_open = false;
 642 }
 643
 644 bool wxClipboard::IsOpened() const
 645 {
 646     return m_open;
 647 }
 648
 649 bool wxClipboard::IsSupported( const wxDataFormat& format )
 650 {
 651     if ( DoIsSupported(format) )
 652         return true;
 653
 654 #if wxUSE_UNICODE
 655     if ( format == wxDF_UNICODETEXT )
 656     {
 657         // also with plain STRING format
 658         return DoIsSupported(g_altTextAtom);
 659     }
 660 #endif // wxUSE_UNICODE
 661
 662     return false;
 663 }
 664
 665 bool wxClipboard::GetData( wxDataObject& data )
 666 {
 667     wxCHECK_MSG( m_open, false, wxT("clipboard not open") );
 668
 669     // get all supported formats from wxDataObjects
 670     const size_t count = data.GetFormatCount();
 671     wxDataFormatArray formats(new wxDataFormat[count]);
 672     data.GetAllFormats(formats.get());
 673
 674     for ( size_t i = 0; i < count; i++ )
 675     {
 676         const wxDataFormat format(formats[i]);
 677
 678         // is this format supported by clipboard ?
 679         if ( !DoIsSupported(format) )
 680             continue;
 681
 682         wxLogTrace(TRACE_CLIPBOARD, wxT("Requesting format %s"),
 683                    format.GetId().c_str());
 684
 685         // these variables will be used by our GTKOnSelectionReceived()
 686         m_receivedData = &data;
 687         m_formatSupported = false;
 688
 689         {
 690             wxClipboardSync sync(*this);
 691
 692             gtk_selection_convert(m_clipboardWidget,
 693                                   GTKGetClipboardAtom(),
 694                                   format,
 695                                   (guint32) GDK_CURRENT_TIME );
 696         } // wait until we get the results
 697
 698         /*
 699            Normally this is a true error as we checked for the presence of such
 700            data before, but there are applications that may return an empty
 701            string (e.g. Gnumeric-1.6.1 on Linux if an empty cell is copied)
 702            which would produce a false error message here, so we check for the
 703            size of the string first. With ANSI, GetDataSize returns an extra
 704            value (for the closing null?), with unicode, the exact number of
 705            tokens is given (that is more than 1 for non-ASCII characters)
 706            (tested with Gnumeric-1.6.1 and OpenOffice.org-2.0.2)
 707          */
 708 #if wxUSE_UNICODE
 709         if ( format != wxDF_UNICODETEXT || data.GetDataSize(format) > 0 )
 710 #else // !UNICODE
 711         if ( format != wxDF_TEXT || data.GetDataSize(format) > 1 )
 712 #endif // UNICODE / !UNICODE
 713         {
 714             wxCHECK_MSG( m_formatSupported, false,
 715                          wxT("error retrieving data from clipboard") );
 716         }
 717
 718         return true;
 719     }
 720
 721     wxLogTrace(TRACE_CLIPBOARD, wxT("GetData(): format not found"));
 722
 723     return false;
 724 }
 725
 726 #endif // wxUSE_CLIPBOARD