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Fix typo in last commit
[wxWidgets.git] / src / gtk / clipbrd.cpp
diff --git a/src/gtk/clipbrd.cpp b/src/gtk/clipbrd.cpp
index 0067d971bc3ab1d54ce5257473067574e9d2bdcc..6e02151f4be01e56acd769335aeb58da61497047 100644 (file)
--- a/src/gtk/clipbrd.cpp
+++ b/src/gtk/clipbrd.cpp
@@ -1,12 +1,21 @@
 /////////////////////////////////////////////////////////////////////////////
 // Name:        src/gtk/clipbrd.cpp
 /////////////////////////////////////////////////////////////////////////////
 // Name:        src/gtk/clipbrd.cpp
-// Purpose:
-// Author:      Robert Roebling
+// Purpose:     wxClipboard implementation for wxGTK
+// Author:      Robert Roebling, Vadim Zeitlin
 // Id:          $Id$
 // Copyright:   (c) 1998 Robert Roebling
 // Id:          $Id$
 // Copyright:   (c) 1998 Robert Roebling
+//              (c) 2007 Vadim Zeitlin
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
+// ============================================================================
+// declarations
+// ============================================================================
+
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
 // For compilers that support precompilation, includes "wx.h".
 #include "wx/wxprec.h"
 
 // For compilers that support precompilation, includes "wx.h".
 #include "wx/wxprec.h"
 
@@ -15,20 +24,27 @@
 #include "wx/clipbrd.h"
 
 #ifndef WX_PRECOMP
 #include "wx/clipbrd.h"
 
 #ifndef WX_PRECOMP
+    #include "wx/app.h"
     #include "wx/log.h"
     #include "wx/utils.h"
     #include "wx/dataobj.h"
 #endif
 
     #include "wx/log.h"
     #include "wx/utils.h"
     #include "wx/dataobj.h"
 #endif
 
+#include "wx/scopedarray.h"
+#include "wx/scopeguard.h"
+#include "wx/evtloop.h"
+
 #include "wx/gtk/private.h"
 
 #include "wx/gtk/private.h"
 
-//-----------------------------------------------------------------------------
+typedef wxScopedArray<wxDataFormat> wxDataFormatArray;
+
+// ----------------------------------------------------------------------------
 // data
 // data
-//-----------------------------------------------------------------------------
+// ----------------------------------------------------------------------------
 
 
-GdkAtom  g_clipboardAtom   = 0;
-GdkAtom  g_targetsAtom     = 0;
-GdkAtom  g_timestampAtom   = 0;
+static GdkAtom  g_clipboardAtom   = 0;
+static GdkAtom  g_targetsAtom     = 0;
+static GdkAtom  g_timestampAtom   = 0;
 
 #if wxUSE_UNICODE
 extern GdkAtom g_altTextAtom;
 
 #if wxUSE_UNICODE
 extern GdkAtom g_altTextAtom;
@@ -37,32 +53,69 @@ extern GdkAtom g_altTextAtom;
 // 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!)
 // 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 _T("clipboard")
+#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
+{
+public:
+    wxClipboardSync(wxClipboard& clipboard)
+    {
+        wxASSERT_MSG( !ms_clipboard, wxT("reentrancy in clipboard code") );
+        ms_clipboard = &clipboard;
+    }
 
 
-//-----------------------------------------------------------------------------
-// reminder
-//-----------------------------------------------------------------------------
+    ~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") );
 
 
-/* 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)
+        ms_clipboard = NULL;
+    }
 
 
-struct _GtkSelectionData
-{
-  GdkAtom selection;
-  GdkAtom target;
-  GdkAtom type;
-  gint    format;
-  guchar *data;
-  gint    length;
+    // 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
@@ -75,57 +128,61 @@ targets_selection_received( GtkWidget *WXUNUSED(widget),
                             guint32 WXUNUSED(time),
                             wxClipboard *clipboard )
 {
                             guint32 WXUNUSED(time),
                             wxClipboard *clipboard )
 {
-    if ( wxTheClipboard && selection_data->length > 0 )
-    {
-        // make sure we got the data in the correct form
-        GdkAtom type = selection_data->type;
-        if ( type != GDK_SELECTION_TYPE_ATOM )
-        {
-            if ( strcmp(wxGtkString(gdk_atom_name(type)), "TARGETS") )
-            {
-                wxLogTrace( TRACE_CLIPBOARD,
-                            _T("got unsupported clipboard target") );
-
-                clipboard->m_waiting = false;
-                return;
-            }
-        }
+    if ( !clipboard )
+        return;
 
 
-#ifdef __WXDEBUG__
-        wxDataFormat clip( selection_data->selection );
-        wxLogTrace( TRACE_CLIPBOARD,
-                    wxT("selection received for targets, clipboard %s"),
-                    clip.GetId().c_str() );
-#endif // __WXDEBUG__
+    wxON_BLOCK_EXIT1(wxClipboardSync::OnDone, clipboard);
 
 
-        // the atoms we received, holding a list of targets (= formats)
-        GdkAtom *atoms = (GdkAtom *)selection_data->data;
+    if (!selection_data)
+        return;
 
 
-        for (unsigned int i=0; i<selection_data->length/sizeof(GdkAtom); i++)
-        {
-            wxDataFormat format( atoms[i] );
+    const int selection_data_length = gtk_selection_data_get_length(selection_data);
+    if (selection_data_length <= 0)
+        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,
             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;
-            }
+                        wxT("got unsupported clipboard target") );
+
+            return;
         }
     }
 
         }
     }
 
-    clipboard->m_waiting = false;
+    // 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
 //-----------------------------------------------------------------------------
@@ -137,50 +194,15 @@ selection_received( GtkWidget *WXUNUSED(widget),
                     guint32 WXUNUSED(time),
                     wxClipboard *clipboard )
 {
                     guint32 WXUNUSED(time),
                     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);
 
 
-#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;
+    if (!selection_data || gtk_selection_data_get_length(selection_data) <= 0)
         return;
         return;
-    }
-#endif
-
-    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);
 }
 }
 
 }
 }
 
@@ -192,37 +214,38 @@ 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)
-        {
-            wxLogTrace(TRACE_CLIPBOARD, wxT("wxClipboard will get cleared" ));
+    // the clipboard is no longer in our hands, we don't need data any more
+    clipboard->GTKClearData(kind);
 
 
-            delete wxTheClipboard->m_data;
-            wxTheClipboard->m_data = (wxDataObject*) NULL;
-        }
-    }
-
-    wxTheClipboard->m_waiting = false;
     return TRUE;
 }
 }
     return TRUE;
 }
 }
@@ -239,17 +262,20 @@ selection_handler( GtkWidget *WXUNUSED(widget),
                    guint WXUNUSED(time),
                    gpointer signal_data )
 {
                    guint WXUNUSED(time),
                    gpointer signal_data )
 {
-    if (!wxTheClipboard) return;
-
-    if (!wxTheClipboard->m_data) return;
+    wxClipboard * const clipboard = wxTheClipboard;
+    if ( !clipboard )
+        return;
 
 
-    wxDataObject *data = wxTheClipboard->m_data;
+    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.
 
     // 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)
+    if (gtk_selection_data_get_target(selection_data) == g_timestampAtom)
     {
         guint timestamp = GPOINTER_TO_UINT (signal_data);
         gtk_selection_data_set(selection_data,
     {
         guint timestamp = GPOINTER_TO_UINT (signal_data);
         gtk_selection_data_set(selection_data,
@@ -258,86 +284,180 @@ selection_handler( GtkWidget *WXUNUSED(widget),
                                (guchar*)&(timestamp),
                                sizeof(timestamp));
         wxLogTrace(TRACE_CLIPBOARD,
                                (guchar*)&(timestamp),
                                sizeof(timestamp));
         wxLogTrace(TRACE_CLIPBOARD,
-                   _T("Clipboard TIMESTAMP requested, returning timestamp=%u"),
+                   wxT("Clipboard TIMESTAMP requested, returning timestamp=%u"),
                    timestamp);
         return;
     }
 
                    timestamp);
         return;
     }
 
-    wxDataFormat format( selection_data->target );
+    wxDataFormat format(gtk_selection_data_get_target(selection_data));
 
 
-#ifdef __WXDEBUG__
     wxLogTrace(TRACE_CLIPBOARD,
     wxLogTrace(TRACE_CLIPBOARD,
-               _T("clipboard data in format %s, GtkSelectionData is target=%s type=%s selection=%s timestamp=%u"),
+               wxT("clipboard data in format %s, GtkSelectionData is target=%s type=%s selection=%s timestamp=%u"),
                format.GetId().c_str(),
                format.GetId().c_str(),
-               wxString::FromAscii(wxGtkString(gdk_atom_name(selection_data->target))).c_str(),
-               wxString::FromAscii(wxGtkString(gdk_atom_name(selection_data->type))).c_str(),
-               wxString::FromAscii(wxGtkString(gdk_atom_name(selection_data->selection))).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 )
                );
                GPOINTER_TO_UINT( signal_data )
                );
-#endif
 
 
-    if (!data->IsSupportedFormat( format )) return;
+    if ( !data->IsSupportedFormat( format ) )
+        return;
 
     int size = data->GetDataSize( format );
 
     int size = data->GetDataSize( format );
+    if ( !size )
+        return;
 
 
-    if (size == 0) return;
-
-    void *d = malloc(size);
+    wxCharBuffer buf(size - 1); // it adds 1 internally (for NUL)
 
 
-    // Text data will be in UTF8 in Unicode mode.
-    data->GetDataHere( selection_data->target, d );
+    // text data must be returned in UTF8 if format is wxDF_UNICODETEXT
+    if ( !data->GetDataHere(format, buf.data()) )
+        return;
 
 
-    // NB: GTK+ requires special treatment of UTF8_STRING data, the text
-    //     would show as UTF-8 data interpreted as latin1 (?) in other
-    //     GTK+ apps if we used gtk_selection_data_set()
+    // 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 (format == wxDataFormat(wxDF_UNICODETEXT))
     {
         gtk_selection_data_set_text(
             selection_data,
     if (format == wxDataFormat(wxDF_UNICODETEXT))
     {
         gtk_selection_data_set_text(
             selection_data,
-            (const gchar*)d,
+            (const gchar*)buf.data(),
             size );
     }
     else
             size );
     }
     else
+#endif // wxUSE_UNICODE
     {
         gtk_selection_data_set(
             selection_data,
             GDK_SELECTION_TYPE_STRING,
             8*sizeof(gchar),
     {
         gtk_selection_data_set(
             selection_data,
             GDK_SELECTION_TYPE_STRING,
             8*sizeof(gchar),
-            (unsigned char*) d,
+            (const guchar*)buf.data(),
             size );
     }
             size );
     }
-
-    free(d);
 }
 }
 
 }
 }
 
+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) )
+        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()
 {
     m_open = false;
 IMPLEMENT_DYNAMIC_CLASS(wxClipboard,wxObject)
 
 wxClipboard::wxClipboard()
 {
     m_open = false;
-    m_waiting = false;
-
-    m_ownsClipboard = false;
-    m_ownsPrimarySelection = false;
 
 
-    m_data = (wxDataObject*) NULL;
-    m_receivedData = (wxDataObject*) NULL;
+    m_dataPrimary =
+    m_dataClipboard =
+    m_receivedData = NULL;
 
 
-    /* we use m_targetsWidget to query what formats are available */
+    m_formatSupported = false;
+    m_targetRequested = 0;
 
 
+    // we use m_targetsWidget to query what formats are available
     m_targetsWidget = gtk_window_new( GTK_WINDOW_POPUP );
     gtk_widget_realize( m_targetsWidget );
 
     g_signal_connect (m_targetsWidget, "selection_received",
                       G_CALLBACK (targets_selection_received), this);
 
     m_targetsWidget = gtk_window_new( GTK_WINDOW_POPUP );
     gtk_widget_realize( m_targetsWidget );
 
     g_signal_connect (m_targetsWidget, "selection_received",
                       G_CALLBACK (targets_selection_received), this);
 
-    /* we use m_clipboardWidget to get and to offer data */
+    // 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 );
 
@@ -347,60 +467,125 @@ wxClipboard::wxClipboard()
     g_signal_connect (m_clipboardWidget, "selection_clear_event",
                       G_CALLBACK (selection_clear_clip), NULL);
 
     g_signal_connect (m_clipboardWidget, "selection_clear_event",
                       G_CALLBACK (selection_clear_clip), NULL);
 
-    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);
-
-    m_formatSupported = false;
-    m_targetRequested = 0;
-
-    m_usePrimary = false;
+    // 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()
 {
     Clear();
 
 }
 
 wxClipboard::~wxClipboard()
 {
     Clear();
 
-    if (m_clipboardWidget) gtk_widget_destroy( m_clipboardWidget );
-    if (m_targetsWidget) gtk_widget_destroy( m_targetsWidget );
+    gtk_widget_destroy( m_clipboardWidget );
+    gtk_widget_destroy( m_targetsWidget );
 }
 
 }
 
-void wxClipboard::Clear()
+// ----------------------------------------------------------------------------
+// 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)
 {
 {
-    if (m_data)
+    bool rc = gtk_selection_owner_set
+              (
+                set ? m_clipboardWidget : NULL,
+                GTKGetClipboardAtom(),
+                (guint32)GDK_CURRENT_TIME
+              );
+
+    if ( !rc )
     {
     {
-#if wxUSE_THREADS
-        /* disable GUI threads */
-#endif
+        wxLogTrace(TRACE_CLIPBOARD, wxT("Failed to %sset selection owner"),
+                   set ? wxT("") : wxT("un"));
+    }
 
 
-        //  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;
+    return rc;
+}
 
 
-            gtk_selection_owner_set( (GtkWidget*) NULL, g_clipboardAtom,
-                                     (guint32) GDK_CURRENT_TIME );
+void wxClipboard::AddSupportedTarget(GdkAtom atom)
+{
+    gtk_selection_add_target
+    (
+        m_clipboardWidget,
+        GTKGetClipboardAtom(),
+        atom,
+        0 // info (same as client data) unused
+    );
+}
 
 
-            while (m_waiting) gtk_main_iteration();
-        }
+bool wxClipboard::IsSupportedAsync(wxEvtHandler *sink)
+{
+    if (m_sink.get())
+        return false;  // currently busy, come back later
 
 
-        if (gdk_selection_owner_get( GDK_SELECTION_PRIMARY ) == m_clipboardWidget->window)
-        {
-            m_waiting = true;
+    wxCHECK_MSG( sink, false, wxT("no sink given") );
 
 
-            gtk_selection_owner_set( (GtkWidget*) NULL, GDK_SELECTION_PRIMARY,
-                                     (guint32) GDK_CURRENT_TIME );
+    m_sink = sink;
+    gtk_selection_convert( m_targetsWidgetAsync,
+                           GTKGetClipboardAtom(),
+                           g_targetsAtom,
+                           (guint32) GDK_CURRENT_TIME );
 
 
-            while (m_waiting) gtk_main_iteration();
-        }
+    return true;
+}
 
 
-        delete m_data;
-        m_data = NULL;
+bool wxClipboard::DoIsSupported(const wxDataFormat& format)
+{
+    wxCHECK_MSG( format, false, wxT("invalid clipboard format") );
 
 
-#if wxUSE_THREADS
-        /* re-enable GUI threads */
-#endif
+    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()
+{
+    gtk_selection_clear_targets( m_clipboardWidget, GTKGetClipboardAtom() );
+
+    if ( gdk_selection_owner_get(GTKGetClipboardAtom()) ==
+            gtk_widget_get_window(m_clipboardWidget) )
+    {
+        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;
@@ -433,65 +618,36 @@ bool wxClipboard::AddData( wxDataObject *data )
 
     wxCHECK_MSG( data, false, wxT("data is invalid") );
 
 
     wxCHECK_MSG( data, false, wxT("data is invalid") );
 
-    // we can only store one wxDataObject
+    // we can only store one wxDataObject so clear the old one
     Clear();
 
     Clear();
 
-    m_data = data;
+    Data() = data;
 
     // 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;
+    const size_t count = data->GetFormatCount();
+    wxDataFormatArray formats(new wxDataFormat[count]);
+    data->GetAllFormats(formats.get());
 
 
-    // by default provide TIMESTAMP as a target
-    gtk_selection_add_target( GTK_WIDGET(m_clipboardWidget),
-                              clipboard,
-                              g_timestampAtom,
-                              0 );
+    // always provide TIMESTAMP as a target, see comments in selection_handler
+    // for explanation
+    AddSupportedTarget(g_timestampAtom);
 
 
-    for (size_t i = 0; i < m_data->GetFormatCount(); i++)
+    for ( size_t i = 0; i < count; i++ )
     {
     {
-        wxLogTrace( TRACE_CLIPBOARD,
-                    wxT("wxClipboard now supports atom %s"),
-                    array[i].GetId().c_str() );
+        const wxDataFormat format(formats[i]);
 
 
-//        printf( "added %s\n",
-//                    gdk_atom_name( array[i].GetFormatId() ) );
+        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;
-
     g_signal_connect (m_clipboardWidget, "selection_get",
                       G_CALLBACK (selection_handler),
                       GUINT_TO_POINTER (gtk_get_current_event_time()) );
 
     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 */
-#endif
-
-    /* Tell the world we offer clipboard data */
-    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 */
-#endif
-
-    return res;
+    // tell the world we offer clipboard data
+    return SetSelectionOwner();
 }
 
 void wxClipboard::Close()
 }
 
 void wxClipboard::Close()
@@ -508,136 +664,62 @@ bool wxClipboard::IsOpened() const
 
 bool wxClipboard::IsSupported( const wxDataFormat& format )
 {
 
 bool wxClipboard::IsSupported( const wxDataFormat& format )
 {
-    /* reentrance problems */
-    if (m_waiting) return false;
-
-    /* store requested format to be asked for by callbacks */
-    m_targetRequested = format;
-
-    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 */
-
-    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 ( DoIsSupported(format) )
+        return true;
 
 #if wxUSE_UNICODE
 
 #if wxUSE_UNICODE
-    if (!m_formatSupported && format == wxDataFormat(wxDF_UNICODETEXT))
+    if ( format == wxDF_UNICODETEXT )
     {
     {
-        // Another try with plain STRING format
-        extern GdkAtom g_altTextAtom;
-        return IsSupported(g_altTextAtom);
+        // also with plain STRING format
+        return DoIsSupported(g_altTextAtom);
     }
     }
-#endif
+#endif // wxUSE_UNICODE
 
 
-    return m_formatSupported;
+    return false;
 }
 
 bool wxClipboard::GetData( wxDataObject& data )
 {
     wxCHECK_MSG( m_open, false, wxT("clipboard not open") );
 
 }
 
 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 );
+    // 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 < data.GetFormatCount(); i++)
+    for ( size_t i = 0; i < count; i++ )
     {
     {
-        wxDataFormat format( array[i] );
-
-        wxLogTrace( TRACE_CLIPBOARD,
-                    wxT("wxClipboard::GetData: requested format: %s"),
-                    format.GetId().c_str() );
-
-        /* is data supported by clipboard ? */
+        const wxDataFormat format(formats[i]);
 
 
-        /* store requested format to be asked for by callbacks */
-        m_targetRequested = format;
-
-        wxCHECK_MSG( m_targetRequested, false, wxT("invalid clipboard format") );
-
-        m_formatSupported = false;
+        // is this format supported by clipboard ?
+        if ( !DoIsSupported(format) )
+            continue;
 
 
-       /* 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 */
+        wxLogTrace(TRACE_CLIPBOARD, wxT("Requesting format %s"),
+                   format.GetId().c_str());
 
 
-        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 */
+        // 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;
 
         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;
-
-        wxLogTrace( TRACE_CLIPBOARD,
-                    wxT("wxClipboard::GetData: format found, start convert") );
-
-        gtk_selection_convert( m_clipboardWidget,
-                               m_usePrimary ? (GdkAtom)GDK_SELECTION_PRIMARY
-                                            : g_clipboardAtom,
-                               m_targetRequested,
-                               (guint32) GDK_CURRENT_TIME );
+        {
+            wxClipboardSync sync(*this);
 
 
-        while (m_waiting) gtk_main_iteration();
+            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
 
         /*
            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
+           size of the string first. With ANSI, GetDataSize returns an extra
            value (for the closing null?), with unicode, the exact number of
            value (for the closing null?), with unicode, the exact number of
-           tokens is given (that is more than 1 for special characters)
+           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
            (tested with Gnumeric-1.6.1 and OpenOffice.org-2.0.2)
          */
 #if wxUSE_UNICODE
@@ -650,18 +732,35 @@ bool wxClipboard::GetData( wxDataObject& data )
                          wxT("error retrieving data from clipboard") );
         }
 
                          wxT("error retrieving data from clipboard") );
         }
 
-        /* return success */
-        delete[] array;
         return true;
     }
 
         return true;
     }
 
-    wxLogTrace( TRACE_CLIPBOARD,
-                wxT("wxClipboard::GetData: format not found") );
+    wxLogTrace(TRACE_CLIPBOARD, wxT("GetData(): format not found"));
 
 
-    /* return failure */
-    delete[] array;
     return false;
 }
 
     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)