]> git.saurik.com Git - wxWidgets.git/blobdiff - src/gtk1/clipbrd.cpp
Use the data scheme to load resources in the WebKitGTK+ implementation, rather than...
[wxWidgets.git] / src / gtk1 / clipbrd.cpp
index 186f15bcf4b0840c3b0b6c23aeccf06924ca9019..2c5b0ff8859c0448a076200bde02c5f357b36849 100644 (file)
@@ -1,50 +1,48 @@
 /////////////////////////////////////////////////////////////////////////////
-// Name:        clipbrd.cpp
+// Name:        src/gtk1/clipbrd.cpp
 // Purpose:
 // Author:      Robert Roebling
 // Id:          $Id$
 // Copyright:   (c) 1998 Robert Roebling
-// Licence:           wxWindows licence
+// Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
-#ifdef __GNUG__
-#pragma implementation "clipbrd.h"
-#endif
-
-#include "wx/clipbrd.h"
+// For compilers that support precompilation, includes "wx.h".
+#include "wx/wxprec.h"
 
 #if wxUSE_CLIPBOARD
 
-#include "wx/dataobj.h"
-#include "wx/utils.h"
-#include "wx/log.h"
-
-#include "glib.h"
-#include "gdk/gdk.h"
-#include "gtk/gtk.h"
-
-//-----------------------------------------------------------------------------
-// thread system
-//-----------------------------------------------------------------------------
+#include "wx/clipbrd.h"
 
-#if wxUSE_THREADS
-extern void wxapp_install_thread_wakeup();
-extern void wxapp_uninstall_thread_wakeup();
+#ifndef WX_PRECOMP
+    #include "wx/log.h"
+    #include "wx/utils.h"
+    #include "wx/dataobj.h"
 #endif
 
+#include <glib.h>
+#include <gdk/gdk.h>
+#include <gtk/gtk.h>
+
 //-----------------------------------------------------------------------------
 // data
 //-----------------------------------------------------------------------------
 
 GdkAtom  g_clipboardAtom   = 0;
 GdkAtom  g_targetsAtom     = 0;
+GdkAtom  g_timestampAtom   = 0;
+
+// the trace mask we use with wxLogTrace() - call
+// wxLog::AddTraceMask(TRACE_CLIPBOARD) to enable the trace messages from here
+// (there will be a *lot* of them!)
+#define TRACE_CLIPBOARD "clipboard"
 
 //-----------------------------------------------------------------------------
 // reminder
 //-----------------------------------------------------------------------------
 
 /* The contents of a selection are returned in a GtkSelectionData
-   structure. selection/target identify the request. 
+   structure. selection/target identify the request.
    type specifies the type of the return; if length < 0, and
    the data should be ignored. This structure has object semantics -
    no fields should be modified directly, they should not be created
@@ -57,9 +55,9 @@ struct _GtkSelectionData
   GdkAtom selection;
   GdkAtom target;
   GdkAtom type;
-  gint          format;
+  gint    format;
   guchar *data;
-  gint          length;
+  gint    length;
 };
 
 */
@@ -68,200 +66,232 @@ struct _GtkSelectionData
 // "selection_received" for targets
 //-----------------------------------------------------------------------------
 
+extern "C" {
 static void
-targets_selection_received( GtkWidget *WXUNUSED(widget), 
-                            GtkSelectionData *selection_data, 
-#if (GTK_MINOR_VERSION > 0)
+targets_selection_received( GtkWidget *WXUNUSED(widget),
+                            GtkSelectionData *selection_data,
                             guint32 WXUNUSED(time),
-#endif
                             wxClipboard *clipboard )
 {
-    if (!wxTheClipboard)
-    {
-        clipboard->m_waiting = FALSE;
-        return;
-    }
-  
-    if (selection_data->length <= 0)
-    {
-        clipboard->m_waiting = FALSE;
-        return;
-    }
-    
-    /* make sure we got the data in the correct form */
-    if (selection_data->type != GDK_SELECTION_TYPE_ATOM)
+    if ( wxTheClipboard && selection_data->length > 0 )
     {
-        clipboard->m_waiting = FALSE;
-        return;
-    }
-  
-    // the atoms we received, holding a list of targets (= formats) 
-    GdkAtom *atoms = (GdkAtom *)selection_data->data;
+        // make sure we got the data in the correct form
+        GdkAtom type = selection_data->type;
+        if ( type != GDK_SELECTION_TYPE_ATOM )
+        {
+            gchar* atom_name = gdk_atom_name(type);
+            if ( strcmp(atom_name, "TARGETS") )
+            {
+                wxLogTrace( TRACE_CLIPBOARD,
+                            wxT("got unsupported clipboard target") );
+
+                clipboard->m_waiting = false;
+                g_free(atom_name);
+                return;
+            }
+            g_free(atom_name);
+        }
 
-    for (unsigned int i=0; i<selection_data->length/sizeof(GdkAtom); i++)
-    {
-        wxDataFormat format( atoms[i] );
-      
-        if (format == clipboard->m_targetRequested)
+        wxDataFormat clip( selection_data->selection );
+        wxLogTrace( TRACE_CLIPBOARD,
+                    wxT("selection received for targets, clipboard %s"),
+                    clip.GetId().c_str() );
+
+        // the atoms we received, holding a list of targets (= formats)
+        GdkAtom *atoms = (GdkAtom *)selection_data->data;
+
+        for (unsigned int i=0; i<selection_data->length/sizeof(GdkAtom); i++)
         {
-            clipboard->m_waiting = FALSE;
-            clipboard->m_formatSupported = TRUE;
-            return;
+            wxDataFormat format( atoms[i] );
+
+            wxLogTrace( TRACE_CLIPBOARD,
+                        wxT("selection received for targets, format %s"),
+                        format.GetId().c_str() );
+
+//            printf( "format %s requested %s\n",
+//                    gdk_atom_name( atoms[i] ),
+//                    gdk_atom_name( clipboard->m_targetRequested ) );
+
+            if (format == clipboard->m_targetRequested)
+            {
+                clipboard->m_waiting = false;
+                clipboard->m_formatSupported = true;
+                return;
+            }
         }
     }
 
-    clipboard->m_waiting = FALSE;
-    return;
+    clipboard->m_waiting = false;
+}
 }
 
 //-----------------------------------------------------------------------------
 // "selection_received" for the actual data
 //-----------------------------------------------------------------------------
 
-static void 
-selection_received( GtkWidget *WXUNUSED(widget), 
-                    GtkSelectionData *selection_data, 
-#if (GTK_MINOR_VERSION > 0)
+extern "C" {
+static void
+selection_received( GtkWidget *WXUNUSED(widget),
+                    GtkSelectionData *selection_data,
                     guint32 WXUNUSED(time),
-#endif
                     wxClipboard *clipboard )
 {
     if (!wxTheClipboard)
     {
-        clipboard->m_waiting = FALSE;
+        clipboard->m_waiting = false;
         return;
     }
-  
+
     wxDataObject *data_object = clipboard->m_receivedData;
 
     if (!data_object)
     {
-        clipboard->m_waiting = FALSE;
+        clipboard->m_waiting = false;
         return;
     }
-    
+
     if (selection_data->length <= 0)
     {
-        clipboard->m_waiting = FALSE;
+        clipboard->m_waiting = false;
         return;
     }
-    
+
     wxDataFormat format( selection_data->target );
-  
-    /* make sure we got the data in the correct format */
+
+    // make sure we got the data in the correct format
     if (!data_object->IsSupportedFormat( format ) )
     {
-        clipboard->m_waiting = FALSE;
+        clipboard->m_waiting = false;
         return;
     }
 
-    /* make sure we got the data in the correct form (selection type).
-       if so, copy data to target object */
+#if 0
+    This seems to cause problems somehow
+    // make sure we got the data in the correct form (selection type).
+    // if so, copy data to target object
     if (selection_data->type != GDK_SELECTION_TYPE_STRING)
     {
-        clipboard->m_waiting = FALSE;
+        clipboard->m_waiting = false;
         return;
     }
-            
+#endif
+
     data_object->SetData( format, (size_t) selection_data->length, (const char*) selection_data->data );
-    
-    wxTheClipboard->m_formatSupported = TRUE;
-    clipboard->m_waiting = FALSE;
+
+    wxTheClipboard->m_formatSupported = true;
+    clipboard->m_waiting = false;
+}
 }
 
 //-----------------------------------------------------------------------------
 // "selection_clear"
 //-----------------------------------------------------------------------------
 
+extern "C" {
 static gint
 selection_clear_clip( GtkWidget *WXUNUSED(widget), GdkEventSelection *event )
 {
     if (!wxTheClipboard) return TRUE;
-    
+
     if (event->selection == GDK_SELECTION_PRIMARY)
     {
-        wxTheClipboard->m_ownsPrimarySelection = FALSE;
+        wxTheClipboard->m_ownsPrimarySelection = false;
     }
     else
     if (event->selection == g_clipboardAtom)
     {
-        wxTheClipboard->m_ownsClipboard = FALSE;
+        wxTheClipboard->m_ownsClipboard = false;
     }
     else
     {
-        wxTheClipboard->m_waiting = FALSE;
+        wxTheClipboard->m_waiting = false;
         return FALSE;
     }
-    
+
     if ((!wxTheClipboard->m_ownsPrimarySelection) &&
         (!wxTheClipboard->m_ownsClipboard))
     {
         /* the clipboard is no longer in our hands. we can the delete clipboard data. */
         if (wxTheClipboard->m_data)
         {
-            delete wxTheClipboard->m_data;
-            wxTheClipboard->m_data = (wxDataObject*) NULL;
+            wxLogTrace(TRACE_CLIPBOARD, wxT("wxClipboard will get cleared" ));
+
+            wxDELETE(wxTheClipboard->m_data);
         }
     }
-  
-    wxTheClipboard->m_waiting = FALSE;
+
+    wxTheClipboard->m_waiting = false;
     return TRUE;
 }
+}
 
 //-----------------------------------------------------------------------------
 // selection handler for supplying data
 //-----------------------------------------------------------------------------
 
+extern "C" {
 static void
-selection_handler( GtkWidget *WXUNUSED(widget), GtkSelectionData *selection_data, gpointer WXUNUSED(data) )
+selection_handler( GtkWidget *WXUNUSED(widget),
+                   GtkSelectionData *selection_data,
+                   guint WXUNUSED(info),
+                   guint WXUNUSED(time),
+                   gpointer signal_data )
 {
     if (!wxTheClipboard) return;
-  
+
     if (!wxTheClipboard->m_data) return;
-  
+
     wxDataObject *data = wxTheClipboard->m_data;
-    
-    wxDataFormat format( selection_data->target );
 
-    if (!data->IsSupportedFormat( format )) return;
-  
-    /* this will fail for composite formats */
-    if (format.GetType() == wxDF_TEXT)
+    // ICCCM says that TIMESTAMP is a required atom.
+    // In particular, it satisfies Klipper, which polls
+    // TIMESTAMP to see if the clipboards content has changed.
+    // It shall return the time which was used to set the data.
+    if (selection_data->target == g_timestampAtom)
     {
-        wxTextDataObject *text_object = (wxTextDataObject*) data;
-        wxString text( text_object->GetText() );
-
-#if wxUSE_UNICODE
-        const wxWX2MBbuf s = text.mbc_str();
-        int len = strlen(s);
-#else // more efficient in non-Unicode
-        const char *s = text.c_str();
-        int len = (int) text.Length();
-#endif
-        gtk_selection_data_set( 
-            selection_data, 
-            GDK_SELECTION_TYPE_STRING, 
-            8*sizeof(gchar),
-            (unsigned char*) (const char*) s,
-            len ); 
-                    
+        guint timestamp = GPOINTER_TO_UINT (signal_data);
+        gtk_selection_data_set(selection_data,
+                               GDK_SELECTION_TYPE_INTEGER,
+                               32,
+                               (guchar*)&(timestamp),
+                               sizeof(timestamp));
+        wxLogTrace(TRACE_CLIPBOARD,
+                   wxT("Clipboard TIMESTAMP requested, returning timestamp=%u"),
+                   timestamp);
         return;
     }
 
+    wxDataFormat format( selection_data->target );
+
+    wxLogTrace(TRACE_CLIPBOARD,
+               wxT("clipboard data in format %s, GtkSelectionData is target=%s type=%s selection=%s timestamp=%u"),
+               format.GetId().c_str(),
+               wxString::FromAscii(gdk_atom_name(selection_data->target)).c_str(),
+               wxString::FromAscii(gdk_atom_name(selection_data->type)).c_str(),
+               wxString::FromAscii(gdk_atom_name(selection_data->selection)).c_str(),
+               GPOINTER_TO_UINT( signal_data )
+               );
+
+    if (!data->IsSupportedFormat( format )) return;
+
     int size = data->GetDataSize( format );
-    
+
     if (size == 0) return;
-    
-    char *d = new char[size];
-    
-    data->GetDataHere( selection_data->target, (void*) d );
-
-    gtk_selection_data_set( 
-        selection_data, 
-        GDK_SELECTION_TYPE_STRING, 
-        8*sizeof(gchar), 
-        (unsigned char*) d,
-        size ); 
+
+    void *d = malloc(size);
+
+    // Text data will be in UTF8 in Unicode mode.
+    data->GetDataHere( selection_data->target, d );
+
+    gtk_selection_data_set(
+            selection_data,
+            GDK_SELECTION_TYPE_STRING,
+            8 * sizeof(gchar),
+            (unsigned char*) d,
+            size );
+
+    free(d);
+}
 }
 
 //-----------------------------------------------------------------------------
@@ -272,52 +302,52 @@ IMPLEMENT_DYNAMIC_CLASS(wxClipboard,wxObject)
 
 wxClipboard::wxClipboard()
 {
-    m_open = FALSE;
+    m_open = false;
+    m_waiting = false;
 
-    m_ownsClipboard = FALSE;
-    m_ownsPrimarySelection = FALSE;
+    m_ownsClipboard = false;
+    m_ownsPrimarySelection = false;
 
-    m_data = (wxDataObject*) NULL;
-    m_receivedData = (wxDataObject*) NULL;
+    m_data = NULL;
+    m_receivedData = NULL;
 
     /* we use m_targetsWidget to query what formats are available */
-    
+
     m_targetsWidget = gtk_window_new( GTK_WINDOW_POPUP );
     gtk_widget_realize( m_targetsWidget );
 
-    gtk_signal_connect( GTK_OBJECT(m_targetsWidget), 
+    gtk_signal_connect( GTK_OBJECT(m_targetsWidget),
                         "selection_received",
-                        GTK_SIGNAL_FUNC( targets_selection_received ), 
+                        GTK_SIGNAL_FUNC( targets_selection_received ),
                         (gpointer) this );
-                        
+
     /* we use m_clipboardWidget to get and to offer data */
-    
+
     m_clipboardWidget = gtk_window_new( GTK_WINDOW_POPUP );
     gtk_widget_realize( m_clipboardWidget );
 
-    gtk_signal_connect( GTK_OBJECT(m_clipboardWidget), 
+    gtk_signal_connect( GTK_OBJECT(m_clipboardWidget),
                         "selection_received",
-                        GTK_SIGNAL_FUNC( selection_received ), 
+                        GTK_SIGNAL_FUNC( selection_received ),
                         (gpointer) this );
 
-    gtk_signal_connect( GTK_OBJECT(m_clipboardWidget), 
+    gtk_signal_connect( GTK_OBJECT(m_clipboardWidget),
                         "selection_clear_event",
-                        GTK_SIGNAL_FUNC( selection_clear_clip ), 
+                        GTK_SIGNAL_FUNC( selection_clear_clip ),
                         (gpointer) NULL );
-                      
+
     if (!g_clipboardAtom) g_clipboardAtom = gdk_atom_intern( "CLIPBOARD", FALSE );
     if (!g_targetsAtom) g_targetsAtom = gdk_atom_intern ("TARGETS", FALSE);
-  
-    m_formatSupported = FALSE;
+    if (!g_timestampAtom) g_timestampAtom = gdk_atom_intern ("TIMESTAMP", FALSE);
+
+    m_formatSupported = false;
     m_targetRequested = 0;
-    
-    m_usePrimary = FALSE;
 }
 
 wxClipboard::~wxClipboard()
 {
-    Clear();  
-  
+    Clear();
+
     if (m_clipboardWidget) gtk_widget_destroy( m_clipboardWidget );
     if (m_targetsWidget) gtk_widget_destroy( m_targetsWidget );
 }
@@ -328,60 +358,56 @@ void wxClipboard::Clear()
     {
 #if wxUSE_THREADS
         /* disable GUI threads */
-        wxapp_uninstall_thread_wakeup();
 #endif
-    
-        /*  As we have data we also own the clipboard. Once we no longer own
-            it, clear_selection is called which will set m_data to zero */
+
+        //  As we have data we also own the clipboard. Once we no longer own
+        //  it, clear_selection is called which will set m_data to zero
         if (gdk_selection_owner_get( g_clipboardAtom ) == m_clipboardWidget->window)
         {
-            m_waiting = TRUE;
-            
-            gtk_selection_owner_set( (GtkWidget*) NULL, g_clipboardAtom, GDK_CURRENT_TIME );
-            
+            m_waiting = true;
+
+            gtk_selection_owner_set( NULL, g_clipboardAtom,
+                                     (guint32) GDK_CURRENT_TIME );
+
             while (m_waiting) gtk_main_iteration();
         }
-    
+
         if (gdk_selection_owner_get( GDK_SELECTION_PRIMARY ) == m_clipboardWidget->window)
         {
-            m_waiting = TRUE;
-            
-            gtk_selection_owner_set( (GtkWidget*) NULL, GDK_SELECTION_PRIMARY, GDK_CURRENT_TIME );
-            
+            m_waiting = true;
+
+            gtk_selection_owner_set( NULL, GDK_SELECTION_PRIMARY,
+                                     (guint32) GDK_CURRENT_TIME );
+
             while (m_waiting) gtk_main_iteration();
         }
-    
-        if (m_data)
-        { 
-            delete m_data;
-            m_data = (wxDataObject*) NULL;
-        }
-        
+
+        wxDELETE(m_data);
+
 #if wxUSE_THREADS
         /* re-enable GUI threads */
-        wxapp_install_thread_wakeup();
 #endif
     }
-  
+
     m_targetRequested = 0;
-    m_formatSupported = FALSE;
+    m_formatSupported = false;
 }
 
 bool wxClipboard::Open()
 {
-    wxCHECK_MSG( !m_open, FALSE, wxT("clipboard already open") );
-  
-    m_open = TRUE;
-    
-    return TRUE;
+    wxCHECK_MSG( !m_open, false, wxT("clipboard already open") );
+
+    m_open = true;
+
+    return true;
 }
 
 bool wxClipboard::SetData( wxDataObject *data )
 {
-    wxCHECK_MSG( m_open, FALSE, wxT("clipboard not open") );
-  
-    wxCHECK_MSG( data, FALSE, wxT("data is invalid") );
-  
+    wxCHECK_MSG( m_open, false, wxT("clipboard not open") );
+
+    wxCHECK_MSG( data, false, wxT("data is invalid") );
+
     Clear();
 
     return AddData( data );
@@ -389,93 +415,77 @@ bool wxClipboard::SetData( wxDataObject *data )
 
 bool wxClipboard::AddData( wxDataObject *data )
 {
-    wxCHECK_MSG( m_open, FALSE, wxT("clipboard not open") );
-  
-    wxCHECK_MSG( data, FALSE, wxT("data is invalid") );
-    
-    /* we can only store one wxDataObject */
+    wxCHECK_MSG( m_open, false, wxT("clipboard not open") );
+
+    wxCHECK_MSG( data, false, wxT("data is invalid") );
+
+    // we can only store one wxDataObject
     Clear();
-  
+
     m_data = data;
 
-    /* This should happen automatically, but to be on the safe side */
-    m_ownsClipboard = FALSE;
-    m_ownsPrimarySelection = FALSE;
-    
-    /* get formats from wxDataObjects */
+    // get formats from wxDataObjects
     wxDataFormat *array = new wxDataFormat[ m_data->GetFormatCount() ];
     m_data->GetAllFormats( array );
-    
+
+    // primary selection or clipboard
+    GdkAtom clipboard = m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
+                                     : g_clipboardAtom;
+
+    // by default provide TIMESTAMP as a target
+    gtk_selection_add_target( GTK_WIDGET(m_clipboardWidget),
+                              clipboard,
+                              g_timestampAtom,
+                              0 );
+
     for (size_t i = 0; i < m_data->GetFormatCount(); i++)
     {
-        GdkAtom atom = array[i];
-        wxLogDebug( wxT("Clipboard Supported atom %s"), gdk_atom_name( atom ) );
-
-        /* Add handlers if someone requests data. We currently always
-           offer data to the clipboard and the primary selection. Maybe
-           we should make that depend on the usePrimary flag */
-           
-        gtk_selection_add_target( GTK_WIDGET(m_clipboardWidget), 
-                              GDK_SELECTION_PRIMARY,
-                              atom, 
-                              0 );  /* what is info ? */
-                             
-        gtk_selection_add_target( GTK_WIDGET(m_clipboardWidget), 
-                              g_clipboardAtom,
-                              atom, 
-                              0 );  /* what is info ? */
+        wxLogTrace( TRACE_CLIPBOARD,
+                    wxT("wxClipboard now supports atom %s"),
+                    array[i].GetId().c_str() );
+
+//        printf( "added %s\n",
+//                    gdk_atom_name( array[i].GetFormatId() ) );
+
+        gtk_selection_add_target( GTK_WIDGET(m_clipboardWidget),
+                                  clipboard,
+                                  array[i],
+                                  0 );  /* what is info ? */
     }
 
     delete[] array;
-                             
-    gtk_signal_connect( GTK_OBJECT(m_clipboardWidget), 
+
+    gtk_signal_connect( GTK_OBJECT(m_clipboardWidget),
                         "selection_get",
-                        GTK_SIGNAL_FUNC(selection_handler), 
-                        (gpointer) NULL );
+                        GTK_SIGNAL_FUNC(selection_handler),
+                        GUINT_TO_POINTER( gdk_event_get_time(gtk_get_current_event()) ) );
 
 #if wxUSE_THREADS
-        /* disable GUI threads */
-        wxapp_uninstall_thread_wakeup();
+    /* disable GUI threads */
 #endif
-    
+
     /* Tell the world we offer clipboard data */
-    if (!gtk_selection_owner_set( m_clipboardWidget, 
-                                  g_clipboardAtom,
-                                  GDK_CURRENT_TIME ))
-    {
-#if wxUSE_THREADS
-        /* re-enable GUI threads */
-        wxapp_install_thread_wakeup();
-#endif
-        return FALSE;
-    }
-    m_ownsClipboard = TRUE;
-    
-    if (!gtk_selection_owner_set( m_clipboardWidget, 
-                                  GDK_SELECTION_PRIMARY,
-                                  GDK_CURRENT_TIME ))
-    {  
-#if wxUSE_THREADS
-        /* re-enable GUI threads */
-        wxapp_install_thread_wakeup();
-#endif
-        return FALSE;
-    }
-    m_ownsPrimarySelection = TRUE;
-    
+    bool res = (gtk_selection_owner_set( m_clipboardWidget,
+                                         clipboard,
+                                         (guint32) GDK_CURRENT_TIME ));
+
+    if (m_usePrimary)
+        m_ownsPrimarySelection = res;
+    else
+        m_ownsClipboard = res;
+
 #if wxUSE_THREADS
     /* re-enable GUI threads */
-    wxapp_install_thread_wakeup();
 #endif
-        
-    return TRUE;
+
+    return res;
 }
 
 void wxClipboard::Close()
 {
     wxCHECK_RET( m_open, wxT("clipboard not open") );
-    
-    m_open = FALSE;
+
+    m_open = false;
 }
 
 bool wxClipboard::IsOpened() const
@@ -486,101 +496,150 @@ bool wxClipboard::IsOpened() const
 bool wxClipboard::IsSupported( const wxDataFormat& format )
 {
     /* reentrance problems */
-    if (m_open) return TRUE;
-    
+    if (m_waiting) return false;
+
     /* store requested format to be asked for by callbacks */
     m_targetRequested = format;
-  
-    wxCHECK_MSG( m_targetRequested, FALSE, wxT("invalid clipboard format") );
-    
-    m_formatSupported = FALSE;
-  
-    /* perform query. this will set m_formatSupported to 
-       TRUE if m_targetRequested is supported.
-       alsom we have to wait for the "answer" from the 
+
+    wxLogTrace( TRACE_CLIPBOARD,
+                wxT("wxClipboard:IsSupported: requested format: %s"),
+                format.GetId().c_str() );
+
+    wxCHECK_MSG( m_targetRequested, false, wxT("invalid clipboard format") );
+
+    m_formatSupported = false;
+
+    /* perform query. this will set m_formatSupported to
+       true if m_targetRequested is supported.
+       also, we have to wait for the "answer" from the
        clipboard owner which is an asynchronous process.
-       therefore we set m_waiting = TRUE here and wait
-       until the callback "targets_selection_received" 
-       sets it to FALSE */
+       therefore we set m_waiting = true here and wait
+       until the callback "targets_selection_received"
+       sets it to false */
 
-    m_waiting = TRUE;
+    m_waiting = true;
 
     gtk_selection_convert( m_targetsWidget,
                            m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
-                                        : g_clipboardAtom, 
+                                        : g_clipboardAtom,
                            g_targetsAtom,
-                           GDK_CURRENT_TIME );
+                           (guint32) GDK_CURRENT_TIME );
 
     while (m_waiting) gtk_main_iteration();
-    
-    if (!m_formatSupported) return FALSE;
-    
-    return TRUE;
-}    
-    
+
+    return m_formatSupported;
+}
+
 bool wxClipboard::GetData( wxDataObject& data )
 {
-    wxCHECK_MSG( m_open, FALSE, wxT("clipboard not open") );
-    
+    wxCHECK_MSG( m_open, false, wxT("clipboard not open") );
+
     /* get formats from wxDataObjects */
     wxDataFormat *array = new wxDataFormat[ data.GetFormatCount() ];
     data.GetAllFormats( array );
-    
+
     for (size_t i = 0; i < data.GetFormatCount(); i++)
     {
         wxDataFormat format( array[i] );
-    
-        wxLogDebug( wxT("wxClipboard::GetData: request format %s"), format.GetId().c_str() );
-    
+
+        wxLogTrace( TRACE_CLIPBOARD,
+                    wxT("wxClipboard::GetData: requested format: %s"),
+                    format.GetId().c_str() );
+
         /* is data supported by clipboard ? */
-        if (!IsSupported( format ))
-           continue;
-    
+
+        /* store requested format to be asked for by callbacks */
+        m_targetRequested = format;
+
+        wxCHECK_MSG( m_targetRequested, false, wxT("invalid clipboard format") );
+
+        m_formatSupported = false;
+
+       /* perform query. this will set m_formatSupported to
+          true if m_targetRequested is supported.
+          also, we have to wait for the "answer" from the
+          clipboard owner which is an asynchronous process.
+          therefore we set m_waiting = true here and wait
+          until the callback "targets_selection_received"
+          sets it to false */
+
+        m_waiting = true;
+
+        gtk_selection_convert( m_targetsWidget,
+                           m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
+                                        : g_clipboardAtom,
+                           g_targetsAtom,
+                           (guint32) GDK_CURRENT_TIME );
+
+        while (m_waiting) gtk_main_iteration();
+
+        if (!m_formatSupported) continue;
+
         /* store pointer to data object to be filled up by callbacks */
         m_receivedData = &data;
-    
+
         /* store requested format to be asked for by callbacks */
         m_targetRequested = format;
-  
-        wxCHECK_MSG( m_targetRequested, FALSE, wxT("invalid clipboard format") );
-    
+
+        wxCHECK_MSG( m_targetRequested, false, wxT("invalid clipboard format") );
+
         /* start query */
-        m_formatSupported = FALSE;
-  
-        /* ask for clipboard contents.  this will set 
-           m_formatSupported to TRUE if m_targetRequested 
+        m_formatSupported = false;
+
+        /* ask for clipboard contents.  this will set
+           m_formatSupported to true if m_targetRequested
            is supported.
-           also, we have to wait for the "answer" from the 
+           also, we have to wait for the "answer" from the
            clipboard owner which is an asynchronous process.
-           therefore we set m_waiting = TRUE here and wait
-           until the callback "targets_selection_received" 
-           sets it to FALSE */
+           therefore we set m_waiting = true here and wait
+           until the callback "targets_selection_received"
+           sets it to false */
 
-        m_waiting = TRUE;
+        m_waiting = true;
+
+        wxLogTrace( TRACE_CLIPBOARD,
+                    wxT("wxClipboard::GetData: format found, start convert") );
 
-        wxLogDebug( wxT("wxClipboard::GetData: format found, start convert") );
-    
         gtk_selection_convert( m_clipboardWidget,
                                m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
-                                            : g_clipboardAtom, 
+                                            : g_clipboardAtom,
                                m_targetRequested,
-                               GDK_CURRENT_TIME );
-  
+                               (guint32) GDK_CURRENT_TIME );
+
         while (m_waiting) gtk_main_iteration();
 
-        /* this is a true error as we checked for the presence of such data before */
-        wxCHECK_MSG( m_formatSupported, FALSE, wxT("error retrieving data from clipboard") );
-        
+        /*
+           Normally this is a true error as we checked for the presence of such
+           data before, but there are applications that may return an empty
+           string (e.g. Gnumeric-1.6.1 on Linux if an empty cell is copied)
+           which would produce a false error message here, so we check for the
+           size of the string first. In ansi, GetDataSize returns an extra
+           value (for the closing null?), with unicode, the exact number of
+           tokens is given (that is more than 1 for special characters)
+           (tested with Gnumeric-1.6.1 and OpenOffice.org-2.0.2)
+         */
+#if wxUSE_UNICODE
+        if ( format != wxDF_UNICODETEXT || data.GetDataSize(format) > 0 )
+#else // !UNICODE
+        if ( format != wxDF_TEXT || data.GetDataSize(format) > 1 )
+#endif // UNICODE / !UNICODE
+        {
+            wxCHECK_MSG( m_formatSupported, false,
+                         wxT("error retrieving data from clipboard") );
+        }
+
         /* return success */
         delete[] array;
-        return TRUE;
+        return true;
     }
-  
+
+    wxLogTrace( TRACE_CLIPBOARD,
+                wxT("wxClipboard::GetData: format not found") );
+
     /* return failure */
     delete[] array;
-    return FALSE;
+    return false;
 }
 
 #endif
   // wxUSE_CLIPBOARD
-