wayland: Port xwayland key grabs to MetaWaylandEventInterface

This event interface simply enforces key focus to the grab window,
but stands out of the way for every other kind of input.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3420>

src/wayland/meta-xwayland-grab-keyboard.c

@@ -35,63 +35,23 @@ struct _MetaXwaylandKeyboardActiveGrab
 {
   MetaWaylandSurface *surface;
   MetaWaylandSeat *seat;
-  MetaWaylandKeyboardGrab keyboard_grab;
+  MetaWaylandEventHandler *handler;
   gulong surface_destroyed_handler;
   gulong shortcuts_restored_handler;
   gulong window_associate_handler;
   struct wl_resource *resource;
 };
 
-static gboolean
-meta_xwayland_keyboard_grab_key (MetaWaylandKeyboardGrab *grab,
-                                 const ClutterEvent      *event)
-{
-  MetaXwaylandKeyboardActiveGrab *active_grab;
-  MetaWaylandKeyboard *keyboard;
-
-  active_grab = wl_container_of (grab, active_grab, keyboard_grab);
-  keyboard = active_grab->keyboard_grab.keyboard;
-
-  /* Force focus onto the surface who has the active grab on the keyboard */
-  if (active_grab->surface != NULL && keyboard->focus_surface != active_grab->surface)
-    meta_wayland_keyboard_set_focus (keyboard, active_grab->surface);
-
-  /* Chain-up with default keyboard handler */
-  return keyboard->default_grab.interface->key (&keyboard->default_grab, event);
-}
-
-static void
-meta_xwayland_keyboard_grab_modifiers (MetaWaylandKeyboardGrab *grab,
-                                       ClutterModifierType      modifiers)
-{
-  MetaXwaylandKeyboardActiveGrab *active_grab;
-  MetaWaylandKeyboard *keyboard;
-
-  active_grab = wl_container_of (grab, active_grab, keyboard_grab);
-  keyboard = active_grab->keyboard_grab.keyboard;
-
-  /* Force focus onto the surface who has the active grab on the keyboard */
-  if (active_grab->surface != NULL && keyboard->focus_surface != active_grab->surface)
-    meta_wayland_keyboard_set_focus (keyboard, active_grab->surface);
-
-  /* Chain-up with default keyboard handler */
- return keyboard->default_grab.interface->modifiers (&keyboard->default_grab,
-                                                     modifiers);
-}
-
 static void
 meta_xwayland_keyboard_grab_end (MetaXwaylandKeyboardActiveGrab *active_grab)
 {
-  MetaWaylandSeat *seat = active_grab->seat;
+  if (active_grab->handler)
-
-  if (seat->keyboard->grab->interface->key == meta_xwayland_keyboard_grab_key)
     {
-      MetaWaylandCompositor *compositor =
+      MetaWaylandInput *input;
-        meta_wayland_seat_get_compositor (active_grab->seat);
 
-      meta_wayland_keyboard_end_grab (active_grab->keyboard_grab.keyboard);
+      input = meta_wayland_seat_get_input (active_grab->seat);
-      meta_wayland_keyboard_set_focus (active_grab->keyboard_grab.keyboard, NULL);
+      meta_wayland_input_detach_event_handler (input, active_grab->handler);
-      meta_wayland_compositor_sync_focus (compositor);
+      active_grab->handler = NULL;
     }
 
   if (!active_grab->surface)
@@ -112,11 +72,45 @@ meta_xwayland_keyboard_grab_end (MetaXwaylandKeyboardActiveGrab *active_grab)
   active_grab->surface = NULL;
 }
 
-static const MetaWaylandKeyboardGrabInterface
+static MetaWaylandSurface *
-  keyboard_grab_interface = {
+meta_xwayland_keyboard_grab_get_focus_surface (MetaWaylandEventHandler *handler,
-    meta_xwayland_keyboard_grab_key,
+                                               ClutterInputDevice      *device,
-    meta_xwayland_keyboard_grab_modifiers
+                                               ClutterEventSequence    *sequence,
-  };
+                                               gpointer                 user_data)
+{
+  MetaXwaylandKeyboardActiveGrab *active_grab = user_data;
+
+  /* Force focus onto the surface who has the active grab on the keyboard */
+  if (clutter_input_device_get_capabilities (device) &
+      CLUTTER_INPUT_CAPABILITY_KEYBOARD)
+    return active_grab->surface;
+
+  return meta_wayland_event_handler_chain_up_get_focus_surface (handler,
+                                                                device,
+                                                                sequence);
+}
+
+static void
+meta_xwayland_keyboard_grab_focus (MetaWaylandEventHandler *handler,
+                                   ClutterInputDevice      *device,
+                                   ClutterEventSequence    *sequence,
+                                   MetaWaylandSurface      *surface,
+                                   gpointer                 user_data)
+{
+  MetaXwaylandKeyboardActiveGrab *active_grab = user_data;
+
+  if (clutter_input_device_get_capabilities (device) &
+      CLUTTER_INPUT_CAPABILITY_KEYBOARD &&
+      surface != active_grab->surface)
+    meta_xwayland_keyboard_grab_end (active_grab);
+  else
+    meta_wayland_event_handler_chain_up_focus (handler, device, sequence, surface);
+}
+
+static const MetaWaylandEventInterface grab_event_interface = {
+  meta_xwayland_keyboard_grab_get_focus_surface,
+  meta_xwayland_keyboard_grab_focus,
+};
 
 static void
 zwp_xwayland_keyboard_grab_destructor (struct wl_resource *resource)
@@ -250,7 +244,15 @@ meta_xwayland_keyboard_grab_activate (MetaXwaylandKeyboardActiveGrab *active_gra
       meta_wayland_surface_inhibit_shortcuts (surface, seat);
 
       if (meta_xwayland_grab_should_lock_focus (window))
-        meta_wayland_keyboard_start_grab (seat->keyboard, &active_grab->keyboard_grab);
+        {
+          MetaWaylandInput *input;
+
+          input = meta_wayland_seat_get_input (seat);
+          active_grab->handler =
+            meta_wayland_input_attach_event_handler (input,
+                                                     &grab_event_interface,
+                                                     active_grab);
+        }
     }
 
   g_clear_signal_handler (&active_grab->window_associate_handler,
@@ -286,7 +288,6 @@ zwp_xwayland_keyboard_grab_manager_grab (struct wl_client   *client,
   active_grab->surface = surface;
   active_grab->resource = grab_resource;
   active_grab->seat = seat;
-  active_grab->keyboard_grab.interface = &keyboard_grab_interface;
   active_grab->surface_destroyed_handler =
     g_signal_connect (surface, "destroy",
                       G_CALLBACK (surface_destroyed_cb),