try to work around IM problems with KDE4 integration (bnc#665112)

See comment for SalKDEDisplay::checkDirectInputEvent(). This was
introduced when switching to using Qt event loop, Qt processes
IM handling before LO gets a chance to do something and this conflicts.
This is rather hackish but I have no better idea and as long as
the IM protocol does not change it should be fine.

ACK by Petr Mladek.

3 files changed, 39 insertions, 0 deletions

diff --git a/vcl/unx/kde4/KDESalDisplay.cxx b/vcl/unx/kde4/KDESalDisplay.cxx
index dbfba3d4da6c..29292b68f142 100644
--- a/vcl/unx/kde4/KDESalDisplay.cxx
+++ b/vcl/unx/kde4/KDESalDisplay.cxx
@@ -41,6 +41,7 @@ SalKDEDisplay::SalKDEDisplay( Display* pDisp )
 {
     assert( selfptr == NULL );
     selfptr = this;
+    xim_protocol = XInternAtom( pDisp_, "_XIM_PROTOCOL", False );
 }
 
 SalKDEDisplay::~SalKDEDisplay()
@@ -65,7 +66,32 @@ void SalKDEDisplay::Yield()
 
     XEvent event;
     XNextEvent( pDisp_, &event );
+    if( checkDirectInputEvent( &event ))
+        return;
     qApp->x11ProcessEvent( &event );
 }
 
+// HACK: When using Qt event loop, input methods (japanese, etc.) will get broken because
+// of XFilterEvent() getting called twice, once by Qt, once by LO (bnc#665112).
+// This function is therefore called before any XEvent is passed to Qt event handling
+// and if it is a keyboard event and no Qt widget is the active window (i.e. we are
+// processing events for some LO window), then feed the event only to LO directly and skip Qt
+// completely. Skipped events are KeyPress, KeyRelease and also _XIM_PROTOCOL client message
+// (seems to be necessary too, hopefully there are not other internal XIM messages that
+// would need this handling).
+bool SalKDEDisplay::checkDirectInputEvent( XEvent* ev )
+{
+    if( ev->xany.type == XLIB_KeyPress || ev->xany.type == KeyRelease
+        || ( ev->xany.type == ClientMessage && ev->xclient.message_type == xim_protocol ))
+    {
+        if( qApp->activeWindow() == NULL )
+        {
+            Dispatch(ev);
+            return true;
+        }
+    }
+    return false;
+}
+
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/unx/kde4/KDESalDisplay.hxx b/vcl/unx/kde4/KDESalDisplay.hxx
index 37a097f5051f..3b7117684942 100644
--- a/vcl/unx/kde4/KDESalDisplay.hxx
+++ b/vcl/unx/kde4/KDESalDisplay.hxx
@@ -41,7 +41,9 @@ class SalKDEDisplay : public SalX11Display
         inline void EventGuardRelease() { osl_releaseMutex( hEventGuard_ ); }
 //        virtual long Dispatch( XEvent *event );
         virtual void Yield();
+        bool checkDirectInputEvent( XEvent* ev );
     private:
+        Atom xim_protocol;
         static SalKDEDisplay* selfptr;
 };
 
diff --git a/vcl/unx/kde4/KDEXLib.cxx b/vcl/unx/kde4/KDEXLib.cxx
index 6544dd86be74..c61a00240721 100644
--- a/vcl/unx/kde4/KDEXLib.cxx
+++ b/vcl/unx/kde4/KDEXLib.cxx
@@ -205,8 +205,19 @@ static GPollFunc old_gpoll = NULL;
 static gint gpoll_wrapper( GPollFD*, guint, gint );
 #endif
 
+static bool ( *old_qt_event_filter )( void* );
+static bool qt_event_filter( void* m )
+{
+    if( old_qt_event_filter != NULL && old_qt_event_filter( m ))
+        return true;
+    if( SalKDEDisplay::self() && SalKDEDisplay::self()->checkDirectInputEvent( static_cast< XEvent* >( m )))
+        return true;
+    return false;
+}
+
 void KDEXLib::setupEventLoop()
 {
+    old_qt_event_filter = QAbstractEventDispatcher::instance()->setEventFilter( qt_event_filter );
 #ifdef GLIB_EVENT_LOOP_SUPPORT
 // Glib is simple, it has g_main_context_set_poll_func() for wrapping the sleep call.
 // The catch is that Qt has a bug that allows triggering timers even when they should