[mutter/wip/carlosg/unfocus-on-modal: 485/485] compositor: Focus the no focus window during modal plugin operations

[Jonas Ådahl <jadahl src gnome org>]

commit e62c9e1c5d6c848044790e7734b66a7e348eac27
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Sep 18 19:49:03 2018 +0200

    compositor: Focus the no focus window during modal plugin operations
    
    Modal operations are usually far from transient, so it makes sense to
    unfocus the currently focused window while the operation is going on.
    If no other window was focused and the window is still alive when the
    modal operation is finished, focus will be restored back.
    
    Closes: https://gitlab.gnome.org/GNOME/gnome-shell/issues/452

 src/compositor/compositor-private.h |  2 ++
 src/compositor/compositor.c         | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+)
---
diff --git a/src/compositor/compositor-private.h b/src/compositor/compositor-private.h
index 0f92d42da..84844c2a9 100644
--- a/src/compositor/compositor-private.h
+++ b/src/compositor/compositor-private.h
@@ -40,6 +40,8 @@ struct _MetaCompositor
 
   MetaPluginManager *plugin_mgr;
 
+  MetaWindow *restore_focus_window;
+
   gboolean frame_has_updated_xsurfaces;
   gboolean have_x11_sync_object;
 };
diff --git a/src/compositor/compositor.c b/src/compositor/compositor.c
index 0854a198b..b7e48d719 100644
--- a/src/compositor/compositor.c
+++ b/src/compositor/compositor.c
@@ -375,6 +375,11 @@ meta_begin_modal_for_plugin (MetaCompositor   *compositor,
   if (!grab_devices (options, timestamp))
     return FALSE;
 
+  g_set_object (&compositor->restore_focus_window,
+                meta_display_get_focus_window (display));
+  meta_x11_display_focus_the_no_focus_window (display->x11_display,
+                                              timestamp);
+
   display->grab_op = META_GRAB_OP_COMPOSITOR;
   display->event_route = META_EVENT_ROUTE_COMPOSITOR_GRAB;
   display->grab_window = NULL;
@@ -418,6 +423,19 @@ meta_end_modal_for_plugin (MetaCompositor *compositor,
   display->grab_have_pointer = FALSE;
   display->grab_have_keyboard = FALSE;
 
+  if (compositor->restore_focus_window)
+    {
+      if (!compositor->restore_focus_window->unmanaging &&
+          !meta_display_get_focus_window (display))
+        {
+          meta_x11_display_set_input_focus_window (display->x11_display,
+                                                   compositor->restore_focus_window,
+                                                   FALSE, timestamp);
+        }
+
+      g_clear_object (&compositor->restore_focus_window);
+    }
+
   meta_backend_ungrab_device (backend, META_VIRTUAL_CORE_POINTER_ID, timestamp);
   meta_backend_ungrab_device (backend, META_VIRTUAL_CORE_KEYBOARD_ID, timestamp);