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revert nested event loop support for wxGTK1 because it causes applications hangs
[wxWidgets.git] / src / gtk / clipbrd.cpp
diff --git a/src/gtk/clipbrd.cpp b/src/gtk/clipbrd.cpp
index 1800ae26852148a26ad9e7d8b28b5026a0d2c5bb..c1c9c9c99bddf6fbf0e00db473919e25f0a167a4 100644 (file)
--- a/src/gtk/clipbrd.cpp
+++ b/src/gtk/clipbrd.cpp
@@ -1,398 +1,613 @@
 /////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////
-// Name:        clipbrd.cpp
-// Purpose:
-// Author:      Robert Roebling
-// Id:          $Id$
+// Name:        src/gtk/clipbrd.cpp
+// Purpose:     wxClipboard implementation for wxGTK
+// Author:      Robert Roebling, Vadim Zeitlin
 // Copyright:   (c) 1998 Robert Roebling
 // Copyright:   (c) 1998 Robert Roebling
-// Licence:           wxWindows licence
+//              (c) 2007 Vadim Zeitlin
+// Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 /////////////////////////////////////////////////////////////////////////////
 
-#ifdef __GNUG__
-#pragma implementation "clipbrd.h"
-#endif
+// ============================================================================
+// declarations
+// ============================================================================
 
 
-#include "wx/clipbrd.h"
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+// For compilers that support precompilation, includes "wx.h".
+#include "wx/wxprec.h"
 
 #if wxUSE_CLIPBOARD
 
 
 #if wxUSE_CLIPBOARD
 
-#include "wx/dataobj.h"
-#include "wx/utils.h"
-#include "wx/log.h"
+#include "wx/clipbrd.h"
 
 
-#include "glib.h"
-#include "gdk/gdk.h"
-#include "gtk/gtk.h"
+#ifndef WX_PRECOMP
+    #include "wx/app.h"
+    #include "wx/log.h"
+    #include "wx/utils.h"
+    #include "wx/dataobj.h"
+#endif
 
 
-//-----------------------------------------------------------------------------
-// thread system
-//-----------------------------------------------------------------------------
+#include "wx/scopedarray.h"
+#include "wx/scopeguard.h"
+#include "wx/evtloop.h"
 
 
-#if wxUSE_THREADS
-extern void wxapp_install_thread_wakeup();
-extern void wxapp_uninstall_thread_wakeup();
-#endif
+#include "wx/gtk/private.h"
 
 
-//-----------------------------------------------------------------------------
-// data
-//-----------------------------------------------------------------------------
+typedef wxScopedArray<wxDataFormat> wxDataFormatArray;
 
 
-GdkAtom  g_clipboardAtom   = 0;
-GdkAtom  g_targetsAtom     = 0;
+// ----------------------------------------------------------------------------
+// data
+// ----------------------------------------------------------------------------
 
 
-//-----------------------------------------------------------------------------
-// reminder
-//-----------------------------------------------------------------------------
+static GdkAtom  g_clipboardAtom   = 0;
+static GdkAtom  g_targetsAtom     = 0;
+static GdkAtom  g_timestampAtom   = 0;
 
 
-/* The contents of a selection are returned in a GtkSelectionData
-   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
-   directly, and pointers to them should not be stored beyond the duration of
-   a callback. (If the last is changed, we'll need to add reference
-   counting)
+#if wxUSE_UNICODE
+extern GdkAtom g_altTextAtom;
+#endif
 
 
-struct _GtkSelectionData
+// 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 wxT("clipboard")
+
+// ----------------------------------------------------------------------------
+// wxClipboardSync: used to perform clipboard operations synchronously
+// ----------------------------------------------------------------------------
+
+// constructing this object on stack will wait wait until the latest clipboard
+// operation is finished on block exit
+//
+// notice that there can be no more than one such object alive at any moment,
+// i.e. reentrancies are not allowed
+class wxClipboardSync
 {
 {
-  GdkAtom selection;
-  GdkAtom target;
-  GdkAtom type;
-  gint          format;
-  guchar *data;
-  gint          length;
+public:
+    wxClipboardSync(wxClipboard& clipboard)
+    {
+        wxASSERT_MSG( !ms_clipboard, wxT("reentrancy in clipboard code") );
+        ms_clipboard = &clipboard;
+    }
+
+    ~wxClipboardSync()
+    {
+#if wxUSE_CONSOLE_EVENTLOOP
+        // ensure that there is a running event loop: this might not be the
+        // case if we're called before the main event loop startup
+        wxEventLoopGuarantor ensureEventLoop;
+#endif
+        while (ms_clipboard)
+            wxEventLoopBase::GetActive()->YieldFor(wxEVT_CATEGORY_CLIPBOARD);
+    }
+
+    // this method must be called by GTK+ callbacks to indicate that we got the
+    // result for our clipboard operation
+    static void OnDone(wxClipboard * WXUNUSED_UNLESS_DEBUG(clipboard))
+    {
+        wxASSERT_MSG( clipboard == ms_clipboard,
+                        wxT("got notification for alien clipboard") );
+
+        ms_clipboard = NULL;
+    }
+
+    // this method should be called if it's possible that no async clipboard
+    // operation is currently in progress (like it can be the case when the
+    // clipboard is cleared but not because we asked about it), it should only
+    // be called if such situation is expected -- otherwise call OnDone() which
+    // would assert in this case
+    static void OnDoneIfInProgress(wxClipboard *clipboard)
+    {
+        if ( ms_clipboard )
+            OnDone(clipboard);
+    }
+
+private:
+    static wxClipboard *ms_clipboard;
+
+    wxDECLARE_NO_COPY_CLASS(wxClipboardSync);
 };
 
 };
 
-*/
+wxClipboard *wxClipboardSync::ms_clipboard = NULL;
+
+// ============================================================================
+// clipboard callbacks implementation
+// ============================================================================
 
 //-----------------------------------------------------------------------------
 // "selection_received" for targets
 //-----------------------------------------------------------------------------
 
 
 //-----------------------------------------------------------------------------
 // "selection_received" for targets
 //-----------------------------------------------------------------------------
 
+extern "C" {
 static void
 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),
                             guint32 WXUNUSED(time),
-#endif
                             wxClipboard *clipboard )
 {
                             wxClipboard *clipboard )
 {
-    if (!wxTheClipboard)
-    {
-        clipboard->m_waiting = FALSE;
+    if ( !clipboard )
         return;
         return;
-    }
-  
-    if (selection_data->length <= 0)
-    {
-        clipboard->m_waiting = FALSE;
+
+    wxON_BLOCK_EXIT1(wxClipboardSync::OnDone, clipboard);
+
+    if (!selection_data)
         return;
         return;
-    }
-    
-    /* make sure we got the data in the correct form */
-    if (selection_data->type != GDK_SELECTION_TYPE_ATOM)
-    {
-        clipboard->m_waiting = FALSE;
+
+    const int selection_data_length = gtk_selection_data_get_length(selection_data);
+    if (selection_data_length <= 0)
         return;
         return;
-    }
-    
-/*
-    wxDataFormat clip( selection_data->selection );
-    wxLogDebug( 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++)
-    {
-        wxDataFormat format( atoms[i] );
-       
-/*
-       wxLogDebug( wxT("selection received for targets, format %s"), format.GetId().c_str() );
-*/
 
 
-        if (format == clipboard->m_targetRequested)
+    // make sure we got the data in the correct form
+    GdkAtom type = gtk_selection_data_get_data_type(selection_data);
+    if ( type != GDK_SELECTION_TYPE_ATOM )
+    {
+        if ( strcmp(wxGtkString(gdk_atom_name(type)), "TARGETS") != 0 )
         {
         {
-            clipboard->m_waiting = FALSE;
-            clipboard->m_formatSupported = TRUE;
+            wxLogTrace( TRACE_CLIPBOARD,
+                        wxT("got unsupported clipboard target") );
+
             return;
         }
     }
 
             return;
         }
     }
 
-    clipboard->m_waiting = FALSE;
-    return;
+    // it's not really a format, of course, but we can reuse its GetId() method
+    // to format this atom as string
+    wxDataFormat clip(gtk_selection_data_get_selection(selection_data));
+    wxLogTrace( TRACE_CLIPBOARD,
+                wxT("Received available formats for clipboard %s"),
+                clip.GetId().c_str() );
+
+    // the atoms we received, holding a list of targets (= formats)
+    const GdkAtom* const atoms = (GdkAtom*)gtk_selection_data_get_data(selection_data);
+    for (size_t i = 0; i < selection_data_length / sizeof(GdkAtom); i++)
+    {
+        const wxDataFormat format(atoms[i]);
+
+        wxLogTrace(TRACE_CLIPBOARD, wxT("\t%s"), format.GetId().c_str());
+
+        if ( clipboard->GTKOnTargetReceived(format) )
+            return;
+    }
+}
+}
+
+bool wxClipboard::GTKOnTargetReceived(const wxDataFormat& format)
+{
+    if ( format != m_targetRequested )
+        return false;
+
+    m_formatSupported = true;
+    return true;
 }
 
 //-----------------------------------------------------------------------------
 // "selection_received" for the actual data
 //-----------------------------------------------------------------------------
 
 }
 
 //-----------------------------------------------------------------------------
 // "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),
                     guint32 WXUNUSED(time),
-#endif
                     wxClipboard *clipboard )
 {
                     wxClipboard *clipboard )
 {
-    if (!wxTheClipboard)
-    {
-        clipboard->m_waiting = FALSE;
+    if ( !clipboard )
         return;
         return;
-    }
-  
-    wxDataObject *data_object = clipboard->m_receivedData;
 
 
-    if (!data_object)
-    {
-        clipboard->m_waiting = FALSE;
-        return;
-    }
-    
-    if (selection_data->length <= 0)
-    {
-        clipboard->m_waiting = FALSE;
-        return;
-    }
-    
-    wxDataFormat format( selection_data->target );
-  
-    /* make sure we got the data in the correct format */
-    if (!data_object->IsSupportedFormat( format ) )
-    {
-        clipboard->m_waiting = FALSE;
-        return;
-    }
+    wxON_BLOCK_EXIT1(wxClipboardSync::OnDone, clipboard);
 
 
-    /* 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;
+    if (!selection_data || gtk_selection_data_get_length(selection_data) <= 0)
         return;
         return;
-    }
-            
-    data_object->SetData( format, (size_t) selection_data->length, (const char*) selection_data->data );
-    
-    wxTheClipboard->m_formatSupported = TRUE;
-    clipboard->m_waiting = FALSE;
+
+    clipboard->GTKOnSelectionReceived(*selection_data);
+}
 }
 
 //-----------------------------------------------------------------------------
 // "selection_clear"
 //-----------------------------------------------------------------------------
 
 }
 
 //-----------------------------------------------------------------------------
 // "selection_clear"
 //-----------------------------------------------------------------------------
 
+extern "C" {
 static gint
 selection_clear_clip( GtkWidget *WXUNUSED(widget), GdkEventSelection *event )
 {
 static gint
 selection_clear_clip( GtkWidget *WXUNUSED(widget), GdkEventSelection *event )
 {
-    if (!wxTheClipboard) return TRUE;
-    
+    wxClipboard * const clipboard = wxTheClipboard;
+    if ( !clipboard )
+        return TRUE;
+
+    // notice the use of OnDoneIfInProgress() here instead of just OnDone():
+    // it's perfectly possible that we're receiving this notification from GTK+
+    // even though we hadn't cleared the clipboard ourselves but because
+    // another application (or even another window in the same program)
+    // acquired it
+    wxON_BLOCK_EXIT1(wxClipboardSync::OnDoneIfInProgress, clipboard);
+
+    wxClipboard::Kind kind;
     if (event->selection == GDK_SELECTION_PRIMARY)
     {
     if (event->selection == GDK_SELECTION_PRIMARY)
     {
-        wxTheClipboard->m_ownsPrimarySelection = FALSE;
+        wxLogTrace(TRACE_CLIPBOARD, wxT("Lost primary selection" ));
+
+        kind = wxClipboard::Primary;
     }
     }
-    else
-    if (event->selection == g_clipboardAtom)
+    else if (event->selection == g_clipboardAtom)
     {
     {
-        wxTheClipboard->m_ownsClipboard = FALSE;
+        wxLogTrace(TRACE_CLIPBOARD, wxT("Lost clipboard" ));
+
+        kind = wxClipboard::Clipboard;
     }
     }
-    else
+    else // some other selection, we're not concerned
     {
     {
-        wxTheClipboard->m_waiting = FALSE;
         return 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)
-        {
-           wxLogDebug( wxT("wxClipboard will get cleared" ) );
-           
-            delete wxTheClipboard->m_data;
-            wxTheClipboard->m_data = (wxDataObject*) NULL;
-        }
-    }
-  
-    wxTheClipboard->m_waiting = FALSE;
+
+    // the clipboard is no longer in our hands, we don't need data any more
+    clipboard->GTKClearData(kind);
+
     return TRUE;
 }
     return TRUE;
 }
+}
 
 //-----------------------------------------------------------------------------
 // selection handler for supplying data
 //-----------------------------------------------------------------------------
 
 
 //-----------------------------------------------------------------------------
 // selection handler for supplying data
 //-----------------------------------------------------------------------------
 
+extern "C" {
 static void
 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)
+    wxClipboard * const clipboard = wxTheClipboard;
+    if ( !clipboard )
+        return;
+
+    wxDataObject * const data = clipboard->GTKGetDataObject(
+        gtk_selection_data_get_selection(selection_data));
+    if ( !data )
+        return;
+
+    // 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 (gtk_selection_data_get_target(selection_data) == g_timestampAtom)
     {
     {
-        wxTextDataObject *text_object = (wxTextDataObject*) data;
-        wxString text( text_object->GetText() );
+        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(gtk_selection_data_get_target(selection_data));
+
+    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(wxGtkString(gdk_atom_name(gtk_selection_data_get_target(selection_data)))).c_str(),
+               wxString::FromAscii(wxGtkString(gdk_atom_name(gtk_selection_data_get_data_type(selection_data)))).c_str(),
+               wxString::FromAscii(wxGtkString(gdk_atom_name(gtk_selection_data_get_selection(selection_data)))).c_str(),
+               GPOINTER_TO_UINT( signal_data )
+               );
+
+    if ( !data->IsSupportedFormat( format ) )
+        return;
+
+    int size = data->GetDataSize( format );
+    if ( !size )
+        return;
 
 
+    wxCharBuffer buf(size - 1); // it adds 1 internally (for NUL)
+
+    // text data must be returned in UTF8 if format is wxDF_UNICODETEXT
+    if ( !data->GetDataHere(format, buf.data()) )
+        return;
+
+    // use UTF8_STRING format if requested in Unicode build but just plain
+    // STRING one in ANSI or if explicitly asked in Unicode
 #if wxUSE_UNICODE
 #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, 
+    if (format == wxDataFormat(wxDF_UNICODETEXT))
+    {
+        gtk_selection_data_set_text(
+            selection_data,
+            (const gchar*)buf.data(),
+            size );
+    }
+    else
+#endif // wxUSE_UNICODE
+    {
+        gtk_selection_data_set(
+            selection_data,
+            format.GetFormatId(),
             8*sizeof(gchar),
             8*sizeof(gchar),
-            (unsigned char*) (const char*) s,
-            len ); 
-                    
-        return;
+            (const guchar*)buf.data(),
+            size );
     }
     }
+}
+}
 
 
-    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 wxClipboard::GTKOnSelectionReceived(const GtkSelectionData& sel)
+{
+    wxCHECK_RET( m_receivedData, wxT("should be inside GetData()") );
+
+    const wxDataFormat format(gtk_selection_data_get_target(const_cast<GtkSelectionData*>(&sel)));
+    wxLogTrace(TRACE_CLIPBOARD, wxT("Received selection %s"),
+               format.GetId().c_str());
+
+    if ( !m_receivedData->IsSupportedFormat(format, wxDataObject::Set) )
+        return;
+
+    m_receivedData->SetData(format,
+        gtk_selection_data_get_length(const_cast<GtkSelectionData*>(&sel)),
+        gtk_selection_data_get_data(const_cast<GtkSelectionData*>(&sel)));
+    m_formatSupported = true;
 }
 
 //-----------------------------------------------------------------------------
 }
 
 //-----------------------------------------------------------------------------
-// wxClipboard
+// asynchronous "selection_received" for targets
 //-----------------------------------------------------------------------------
 
 //-----------------------------------------------------------------------------
 
+extern "C" {
+static void
+async_targets_selection_received( GtkWidget *WXUNUSED(widget),
+                            GtkSelectionData *selection_data,
+                            guint32 WXUNUSED(time),
+                            wxClipboard *clipboard )
+{
+    if ( !clipboard ) // Assert?
+        return;
+
+    if (!clipboard->m_sink)
+        return;
+
+    wxClipboardEvent *event = new wxClipboardEvent(wxEVT_CLIPBOARD_CHANGED);
+    event->SetEventObject( clipboard );
+
+    int selection_data_length = 0;
+    if (selection_data)
+        selection_data_length = gtk_selection_data_get_length(selection_data);
+
+    if (selection_data_length <= 0)
+    {
+        clipboard->m_sink->QueueEvent( event );
+        clipboard->m_sink.Release();
+        return;
+    }
+
+    // make sure we got the data in the correct form
+    GdkAtom type = gtk_selection_data_get_data_type(selection_data);
+    if ( type != GDK_SELECTION_TYPE_ATOM )
+    {
+        if ( strcmp(wxGtkString(gdk_atom_name(type)), "TARGETS") != 0 )
+        {
+            wxLogTrace( TRACE_CLIPBOARD,
+                        wxT("got unsupported clipboard target") );
+
+            clipboard->m_sink->QueueEvent( event );
+            clipboard->m_sink.Release();
+            return;
+        }
+    }
+
+    // it's not really a format, of course, but we can reuse its GetId() method
+    // to format this atom as string
+    wxDataFormat clip(gtk_selection_data_get_selection(selection_data));
+    wxLogTrace( TRACE_CLIPBOARD,
+                wxT("Received available formats for clipboard %s"),
+                clip.GetId().c_str() );
+
+    // the atoms we received, holding a list of targets (= formats)
+    const GdkAtom* const atoms = (GdkAtom*)gtk_selection_data_get_data(selection_data);
+    for (size_t i = 0; i < selection_data_length / sizeof(GdkAtom); i++)
+    {
+        const wxDataFormat format(atoms[i]);
+
+        wxLogTrace(TRACE_CLIPBOARD, wxT("\t%s"), format.GetId().c_str());
+
+        event->AddFormat( format );
+    }
+
+    clipboard->m_sink->QueueEvent( event );
+    clipboard->m_sink.Release();
+}
+}
+
+// ============================================================================
+// wxClipboard implementation
+// ============================================================================
+
+// ----------------------------------------------------------------------------
+// wxClipboard ctor/dtor
+// ----------------------------------------------------------------------------
+
 IMPLEMENT_DYNAMIC_CLASS(wxClipboard,wxObject)
 
 wxClipboard::wxClipboard()
 {
 IMPLEMENT_DYNAMIC_CLASS(wxClipboard,wxObject)
 
 wxClipboard::wxClipboard()
 {
-    m_open = FALSE;
+    m_idSelectionGetHandler = 0;
+
+    m_open = false;
 
 
-    m_ownsClipboard = FALSE;
-    m_ownsPrimarySelection = FALSE;
+    m_dataPrimary =
+    m_dataClipboard =
+    m_receivedData = NULL;
 
 
-    m_data = (wxDataObject*) NULL;
-    m_receivedData = (wxDataObject*) NULL;
+    m_formatSupported = false;
+    m_targetRequested = 0;
 
 
-    /* we use m_targetsWidget to query what formats are available */
-    
+    // we use m_targetsWidget to query what formats are available
     m_targetsWidget = gtk_window_new( GTK_WINDOW_POPUP );
     gtk_widget_realize( m_targetsWidget );
 
     m_targetsWidget = gtk_window_new( GTK_WINDOW_POPUP );
     gtk_widget_realize( m_targetsWidget );
 
-    gtk_signal_connect( GTK_OBJECT(m_targetsWidget), 
-                        "selection_received",
-                        GTK_SIGNAL_FUNC( targets_selection_received ), 
-                        (gpointer) this );
-                        
-    /* we use m_clipboardWidget to get and to offer data */
-    
+    g_signal_connect (m_targetsWidget, "selection_received",
+                      G_CALLBACK (targets_selection_received), this);
+
+    // we use m_targetsWidgetAsync to query what formats are available asynchronously
+    m_targetsWidgetAsync = gtk_window_new( GTK_WINDOW_POPUP );
+    gtk_widget_realize( m_targetsWidgetAsync );
+
+    g_signal_connect (m_targetsWidgetAsync, "selection_received",
+                      G_CALLBACK (async_targets_selection_received), this);
+
+    // we use m_clipboardWidget to get and to offer data
     m_clipboardWidget = gtk_window_new( GTK_WINDOW_POPUP );
     gtk_widget_realize( m_clipboardWidget );
 
     m_clipboardWidget = gtk_window_new( GTK_WINDOW_POPUP );
     gtk_widget_realize( m_clipboardWidget );
 
-    gtk_signal_connect( GTK_OBJECT(m_clipboardWidget), 
-                        "selection_received",
-                        GTK_SIGNAL_FUNC( selection_received ), 
-                        (gpointer) this );
-
-    gtk_signal_connect( GTK_OBJECT(m_clipboardWidget), 
-                        "selection_clear_event",
-                        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;
-    m_targetRequested = 0;
-    
-    m_usePrimary = FALSE;
+    g_signal_connect (m_clipboardWidget, "selection_received",
+                      G_CALLBACK (selection_received), this);
+
+    g_signal_connect (m_clipboardWidget, "selection_clear_event",
+                      G_CALLBACK (selection_clear_clip), NULL);
+
+    // initialize atoms we use if not done yet
+    if ( !g_clipboardAtom )
+        g_clipboardAtom = gdk_atom_intern( "CLIPBOARD", FALSE );
+    if ( !g_targetsAtom )
+        g_targetsAtom = gdk_atom_intern ("TARGETS", FALSE);
+    if ( !g_timestampAtom )
+        g_timestampAtom = gdk_atom_intern ("TIMESTAMP", FALSE);
 }
 
 wxClipboard::~wxClipboard()
 {
 }
 
 wxClipboard::~wxClipboard()
 {
-    Clear();  
-  
-    if (m_clipboardWidget) gtk_widget_destroy( m_clipboardWidget );
-    if (m_targetsWidget) gtk_widget_destroy( m_targetsWidget );
+    Clear();
+
+    gtk_widget_destroy( m_clipboardWidget );
+    gtk_widget_destroy( m_targetsWidget );
+}
+
+// ----------------------------------------------------------------------------
+// wxClipboard helper functions
+// ----------------------------------------------------------------------------
+
+GdkAtom wxClipboard::GTKGetClipboardAtom() const
+{
+    return m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
+                        : g_clipboardAtom;
+}
+
+void wxClipboard::GTKClearData(Kind kind)
+{
+    wxDataObject *&data = Data(kind);
+    wxDELETE(data);
+}
+
+bool wxClipboard::SetSelectionOwner(bool set)
+{
+    bool rc = gtk_selection_owner_set
+              (
+                set ? m_clipboardWidget : NULL,
+                GTKGetClipboardAtom(),
+                (guint32)GDK_CURRENT_TIME
+              ) != 0;
+
+    if ( !rc )
+    {
+        wxLogTrace(TRACE_CLIPBOARD, wxT("Failed to %sset selection owner"),
+                   set ? wxT("") : wxT("un"));
+    }
+
+    return rc;
+}
+
+void wxClipboard::AddSupportedTarget(GdkAtom atom)
+{
+    gtk_selection_add_target
+    (
+        m_clipboardWidget,
+        GTKGetClipboardAtom(),
+        atom,
+        0 // info (same as client data) unused
+    );
+}
+
+bool wxClipboard::IsSupportedAsync(wxEvtHandler *sink)
+{
+    if (m_sink.get())
+        return false;  // currently busy, come back later
+
+    wxCHECK_MSG( sink, false, wxT("no sink given") );
+
+    m_sink = sink;
+    gtk_selection_convert( m_targetsWidgetAsync,
+                           GTKGetClipboardAtom(),
+                           g_targetsAtom,
+                           (guint32) GDK_CURRENT_TIME );
+
+    return true;
 }
 
 }
 
+bool wxClipboard::DoIsSupported(const wxDataFormat& format)
+{
+    wxCHECK_MSG( format, false, wxT("invalid clipboard format") );
+
+    wxLogTrace(TRACE_CLIPBOARD, wxT("Checking if format %s is available"),
+               format.GetId().c_str());
+
+    // these variables will be used by our GTKOnTargetReceived()
+    m_targetRequested = format;
+    m_formatSupported = false;
+
+    // block until m_formatSupported is set from targets_selection_received
+    // callback
+    {
+        wxClipboardSync sync(*this);
+
+        gtk_selection_convert( m_targetsWidget,
+                               GTKGetClipboardAtom(),
+                               g_targetsAtom,
+                               (guint32) GDK_CURRENT_TIME );
+    }
+
+    return m_formatSupported;
+}
+
+// ----------------------------------------------------------------------------
+// wxClipboard public API implementation
+// ----------------------------------------------------------------------------
+
 void wxClipboard::Clear()
 {
 void wxClipboard::Clear()
 {
-    if (m_data)
+    gtk_selection_clear_targets( m_clipboardWidget, GTKGetClipboardAtom() );
+
+    if ( gdk_selection_owner_get(GTKGetClipboardAtom()) ==
+            gtk_widget_get_window(m_clipboardWidget) )
     {
     {
-#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 */
-        if (gdk_selection_owner_get( g_clipboardAtom ) == m_clipboardWidget->window)
-        {
-            m_waiting = TRUE;
-            
-            gtk_selection_owner_set( (GtkWidget*) NULL, g_clipboardAtom, 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 );
-            
-            while (m_waiting) gtk_main_iteration();
-        }
-    
-        if (m_data)
-        { 
-            delete m_data;
-            m_data = (wxDataObject*) NULL;
-        }
-        
-#if wxUSE_THREADS
-        /* re-enable GUI threads */
-        wxapp_install_thread_wakeup();
-#endif
+        wxClipboardSync sync(*this);
+
+        // this will result in selection_clear_clip callback being called and
+        // it will free our data
+        SetSelectionOwner(false);
     }
     }
-  
+
     m_targetRequested = 0;
     m_targetRequested = 0;
-    m_formatSupported = FALSE;
+    m_formatSupported = false;
 }
 
 bool wxClipboard::Open()
 {
 }
 
 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 )
 {
 }
 
 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 );
     Clear();
 
     return AddData( data );
@@ -400,69 +615,51 @@ bool wxClipboard::SetData( wxDataObject *data )
 
 bool wxClipboard::AddData( 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 so clear the old one
     Clear();
     Clear();
-  
-    m_data = data;
 
 
-    /* get formats from wxDataObjects */
-    wxDataFormat *array = new wxDataFormat[ m_data->GetFormatCount() ];
-    m_data->GetAllFormats( array );
+    Data() = data;
 
 
-    /* primary selection or clipboard */
-    GdkAtom clipboard = m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
-                                     : g_clipboardAtom;
+    // get formats from wxDataObjects
+    const size_t count = data->GetFormatCount();
+    wxDataFormatArray formats(new wxDataFormat[count]);
+    data->GetAllFormats(formats.get());
 
 
-    
-    for (size_t i = 0; i < m_data->GetFormatCount(); i++)
+    // always provide TIMESTAMP as a target, see comments in selection_handler
+    // for explanation
+    AddSupportedTarget(g_timestampAtom);
+
+    for ( size_t i = 0; i < count; i++ )
     {
     {
-        wxLogDebug( wxT("wxClipboard now supports atom %s"), array[i].GetId().c_str() );
+        const wxDataFormat format(formats[i]);
+
+        wxLogTrace(TRACE_CLIPBOARD, wxT("Adding support for %s"),
+                   format.GetId().c_str());
 
 
-        gtk_selection_add_target( GTK_WIDGET(m_clipboardWidget),
-                                 clipboard,
-                                  array[i], 
-                                  0 );  /* what is info ? */
+        AddSupportedTarget(format);
     }
 
     }
 
-    delete[] array;
-                             
-    gtk_signal_connect( GTK_OBJECT(m_clipboardWidget), 
-                        "selection_get",
-                        GTK_SIGNAL_FUNC(selection_handler), 
-                        (gpointer) NULL );
+    if ( !m_idSelectionGetHandler )
+    {
+        m_idSelectionGetHandler = g_signal_connect (
+                      m_clipboardWidget, "selection_get",
+                      G_CALLBACK (selection_handler),
+                      GUINT_TO_POINTER (gtk_get_current_event_time()) );
+    }
 
 
-#if wxUSE_THREADS
-    /* disable GUI threads */
-    wxapp_uninstall_thread_wakeup();
-#endif
-    
-    /* Tell the world we offer clipboard data */
-    bool res = (gtk_selection_owner_set( m_clipboardWidget,
-                                         clipboard,
-                                         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 res;
+    // tell the world we offer clipboard data
+    return SetSelectionOwner();
 }
 
 void wxClipboard::Close()
 {
     wxCHECK_RET( m_open, wxT("clipboard not open") );
 }
 
 void wxClipboard::Close()
 {
     wxCHECK_RET( m_open, wxT("clipboard not open") );
-    
-    m_open = FALSE;
+
+    m_open = false;
 }
 
 bool wxClipboard::IsOpened() const
 }
 
 bool wxClipboard::IsOpened() const
@@ -472,129 +669,103 @@ bool wxClipboard::IsOpened() const
 
 bool wxClipboard::IsSupported( const wxDataFormat& format )
 {
 
 bool wxClipboard::IsSupported( const wxDataFormat& format )
 {
-    /* reentrance problems */
-    if (m_open) return TRUE;
-    
-    /* 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 
-       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,
-                           GDK_CURRENT_TIME );
+    if ( DoIsSupported(format) )
+        return true;
+
+#if wxUSE_UNICODE
+    if ( format == wxDF_UNICODETEXT )
+    {
+        // also with plain STRING format
+        return DoIsSupported(g_altTextAtom);
+    }
+#endif // wxUSE_UNICODE
+
+    return false;
+}
 
 
-    while (m_waiting) gtk_main_iteration();
-    
-    if (!m_formatSupported) return FALSE;
-    
-    return TRUE;
-}    
-    
 bool wxClipboard::GetData( wxDataObject& data )
 {
 bool wxClipboard::GetData( wxDataObject& data )
 {
-    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++)
+    wxCHECK_MSG( m_open, false, wxT("clipboard not open") );
+
+    // get all supported formats from wxDataObjects: notice that we are setting
+    // the object data, so we need them in "Set" direction
+    const size_t count = data.GetFormatCount(wxDataObject::Set);
+    wxDataFormatArray formats(new wxDataFormat[count]);
+    data.GetAllFormats(formats.get(), wxDataObject::Set);
+
+    for ( size_t i = 0; i < count; i++ )
     {
     {
-        wxDataFormat format( array[i] );
-    
-        wxLogDebug( wxT("wxClipboard::GetData: requested format: %s"), format.GetId().c_str() );
-    
-        /* is data supported by clipboard ? */
-       
-        /* 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;
+        const wxDataFormat format(formats[i]);
 
 
-        gtk_selection_convert( m_targetsWidget,
-                           m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
-                                        : g_clipboardAtom, 
-                           g_targetsAtom,
-                           GDK_CURRENT_TIME );
+        // is this format supported by clipboard ?
+        if ( !DoIsSupported(format) )
+            continue;
+
+        wxLogTrace(TRACE_CLIPBOARD, wxT("Requesting format %s"),
+                   format.GetId().c_str());
 
 
-        while (m_waiting) gtk_main_iteration();
-    
-        if (!m_formatSupported) continue;
-    
-        /* store pointer to data object to be filled up by callbacks */
+        // these variables will be used by our GTKOnSelectionReceived()
         m_receivedData = &data;
         m_receivedData = &data;
-    
-        /* store requested format to be asked for by callbacks */
-        m_targetRequested = 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 
-           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;
-
-        wxLogDebug( wxT("wxClipboard::GetData: format found, start convert") );
-    
-        gtk_selection_convert( m_clipboardWidget,
-                               m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
-                                            : g_clipboardAtom, 
-                               m_targetRequested,
-                               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") );
-        
-        /* return success */
-        delete[] array;
-        return TRUE;
+        m_formatSupported = false;
+
+        {
+            wxClipboardSync sync(*this);
+
+            gtk_selection_convert(m_clipboardWidget,
+                                  GTKGetClipboardAtom(),
+                                  format,
+                                  (guint32) GDK_CURRENT_TIME );
+        } // wait until we get the results
+
+        /*
+           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. With 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 non-ASCII 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 true;
     }
     }
-  
-    wxLogDebug( wxT("wxClipboard::GetData: format not found") );
-    
-    /* return failure */
-    delete[] array;
-    return FALSE;
+
+    wxLogTrace(TRACE_CLIPBOARD, wxT("GetData(): format not found"));
+
+    return false;
 }
 
 }
 
-#endif
-  // wxUSE_CLIPBOARD
+wxDataObject* wxClipboard::GTKGetDataObject( GdkAtom atom )
+{
+    if ( atom == GDK_NONE )
+        return Data();
+
+    if ( atom == GDK_SELECTION_PRIMARY )
+    {
+        wxLogTrace(TRACE_CLIPBOARD, wxT("Primary selection requested" ));
+
+        return Data( wxClipboard::Primary );
+    }
+    else if ( atom == g_clipboardAtom )
+    {
+        wxLogTrace(TRACE_CLIPBOARD, wxT("Clipboard data requested" ));
+
+        return Data( wxClipboard::Clipboard );
+    }
+    else // some other selection, we're not concerned
+    {
+        return (wxDataObject*)NULL;
+    }
+}
 
 
+#endif // wxUSE_CLIPBOARD
wxWidgets (Impactor)