events: Only pass key events to Wayland if focus is on the stage

Even without a compositor grab, key events may still be expected to
be processed by the compositor and not applications, for instance
when using ctrl-alt-tab to keynav in the top bar. On X11, focus is
moved to the stage window in that case, so that events are processed
before they are dispatched by the window manager. On wayland, we need
to handle this case ourselves, so make sure to not pass key events to
wayland in that case, and move the key focus back to the stage when
appropriate.

https://bugzilla.gnome.org/show_bug.cgi?id=758167

src/core/events.c

@@ -47,6 +47,18 @@
                              (e)->type == CLUTTER_TOUCH_END || \
                              (e)->type == CLUTTER_TOUCH_CANCEL)
 
+#define IS_KEY_EVENT(e) ((e)->type == CLUTTER_KEY_PRESS || \
+                         (e)->type == CLUTTER_KEY_RELEASE)
+
+static gboolean
+stage_has_key_focus (void)
+{
+  MetaBackend *backend = meta_get_backend ();
+  ClutterActor *stage = meta_backend_get_stage (backend);
+
+  return clutter_stage_get_key_focus (CLUTTER_STAGE (stage)) == stage;
+}
+
 static MetaWindow *
 get_window_for_event (MetaDisplay        *display,
                       const ClutterEvent *event)
@@ -58,14 +70,8 @@ get_window_for_event (MetaDisplay        *display,
         ClutterActor *source;
 
         /* Always use the key focused window for key events. */
-        switch (event->type)
+        if (IS_KEY_EVENT (event))
-          {
+            return stage_has_key_focus () ? display->focus_window : NULL;
-          case CLUTTER_KEY_PRESS:
-          case CLUTTER_KEY_RELEASE:
-            return display->focus_window;
-          default:
-            break;
-          }
 
         source = clutter_event_get_source (event);
         if (META_IS_SURFACE_ACTOR (source))
@@ -299,6 +305,18 @@ meta_display_handle_event (MetaDisplay        *display,
       goto out;
     }
 
+  /* Do not pass keyboard events to Wayland if key focus is not on the
+   * stage in normal mode (e.g. during keynav in the panel)
+   */
+  if (display->event_route == META_EVENT_ROUTE_NORMAL)
+    {
+      if (IS_KEY_EVENT (event) && !stage_has_key_focus ())
+        {
+          bypass_wayland = TRUE;
+          goto out;
+        }
+    }
+
   if (display->current_pad_osd)
     {
       bypass_wayland = TRUE;

src/core/window.c

@@ -4300,6 +4300,13 @@ meta_window_focus (MetaWindow  *window,
 
   META_WINDOW_GET_CLASS (window)->focus (window, timestamp);
 
+  if (window->display->event_route == META_EVENT_ROUTE_NORMAL)
+    {
+      MetaBackend *backend = meta_get_backend ();
+      ClutterStage *stage = CLUTTER_STAGE (meta_backend_get_stage (backend));
+      clutter_stage_set_key_focus (stage, NULL);
+    }
+
   if (window->wm_state_demands_attention)
     meta_window_unset_demands_attention(window);