wayland/legacy-xdg-shell: Handle requests after toplevel was unmanaged

As with xdg-toplevel proper, a legacy xdg-toplevel can be unmanaged by
the compositor without the client knowing about it, meaning the client
may still send updates and make requests. Handle this gracefully by
ignoring them. The client needs to reassign the surface the legacy
xdg-toplevel role again, if it wants to remap the same surface, meaning
all state would be reset anyway.

Closes: https://gitlab.gnome.org/GNOME/mutter/issues/240

src/wayland/meta-wayland-legacy-xdg-shell.c

@@ -185,6 +185,11 @@ zxdg_toplevel_v6_set_parent (struct wl_client   *client,
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
   MetaWindow *transient_for = NULL;
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (parent_resource)
     {
@@ -194,7 +199,7 @@ zxdg_toplevel_v6_set_parent (struct wl_client   *client,
       transient_for = parent_surface->window;
     }
 
-  meta_window_set_transient_for (surface->window, transient_for);
+  meta_window_set_transient_for (window, transient_for);
 }
 
 static void
@@ -203,11 +208,16 @@ zxdg_toplevel_v6_set_title (struct wl_client   *client,
                             const char         *title)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (!g_utf8_validate (title, -1, NULL))
     title = "";
 
-  meta_window_set_title (surface->window, title);
+  meta_window_set_title (window, title);
 }
 
 static void
@@ -216,11 +226,16 @@ zxdg_toplevel_v6_set_app_id (struct wl_client   *client,
                              const char         *app_id)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (!g_utf8_validate (app_id, -1, NULL))
     app_id = "";
 
-  meta_window_set_wm_class (surface->window, app_id, app_id);
+  meta_window_set_wm_class (window, app_id, app_id);
 }
 
 static void
@@ -233,15 +248,20 @@ zxdg_toplevel_v6_show_window_menu (struct wl_client   *client,
 {
   MetaWaylandSeat *seat = wl_resource_get_user_data (seat_resource);
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
   int monitor_scale;
 
+  window = surface->window;
+  if (!window)
+    return;
+
   if (!meta_wayland_seat_get_grab_info (seat, surface, serial, FALSE, NULL, NULL))
     return;
 
-  monitor_scale = surface->window->monitor->scale;
+  monitor_scale = window->monitor->scale;
-  meta_window_show_menu (surface->window, META_WINDOW_MENU_WM,
+  meta_window_show_menu (window, META_WINDOW_MENU_WM,
-                         surface->window->buffer_rect.x + (x * monitor_scale),
+                         window->buffer_rect.x + (x * monitor_scale),
-                         surface->window->buffer_rect.y + (y * monitor_scale));
+                         window->buffer_rect.y + (y * monitor_scale));
 }
 
 static void
@@ -252,8 +272,13 @@ zxdg_toplevel_v6_move (struct wl_client   *client,
 {
   MetaWaylandSeat *seat = wl_resource_get_user_data (seat_resource);
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
   gfloat x, y;
 
+  window = surface->window;
+  if (!window)
+    return;
+
   if (!meta_wayland_seat_get_grab_info (seat, surface, serial, TRUE, &x, &y))
     return;
 
@@ -292,9 +317,14 @@ zxdg_toplevel_v6_resize (struct wl_client   *client,
 {
   MetaWaylandSeat *seat = wl_resource_get_user_data (seat_resource);
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
   gfloat x, y;
   MetaGrabOp grab_op;
 
+  window = surface->window;
+  if (!window)
+    return;
+
   if (!meta_wayland_seat_get_grab_info (seat, surface, serial, TRUE, &x, &y))
     return;
 
@@ -309,6 +339,11 @@ zxdg_toplevel_v6_set_max_size (struct wl_client   *client,
                                int32_t             height)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (width < 0 || height < 0)
     {
@@ -331,6 +366,11 @@ zxdg_toplevel_v6_set_min_size (struct wl_client   *client,
                                int32_t             height)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (width < 0 || height < 0)
     {
@@ -351,9 +391,14 @@ zxdg_toplevel_v6_set_maximized (struct wl_client   *client,
                                 struct wl_resource *resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
 
-  meta_window_force_placement (surface->window, TRUE);
+  window = surface->window;
-  meta_window_maximize (surface->window, META_MAXIMIZE_BOTH);
+  if (!window)
+    return;
+
+  meta_window_force_placement (window, TRUE);
+  meta_window_maximize (window, META_MAXIMIZE_BOTH);
 }
 
 static void
@@ -361,8 +406,13 @@ zxdg_toplevel_v6_unset_maximized (struct wl_client   *client,
                                   struct wl_resource *resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
 
-  meta_window_unmaximize (surface->window, META_MAXIMIZE_BOTH);
+  window = surface->window;
+  if (!window)
+    return;
+
+  meta_window_unmaximize (window, META_MAXIMIZE_BOTH);
 }
 
 static void
@@ -371,15 +421,20 @@ zxdg_toplevel_v6_set_fullscreen (struct wl_client   *client,
                                  struct wl_resource *output_resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (output_resource)
     {
       MetaWaylandOutput *output = wl_resource_get_user_data (output_resource);
       if (output)
-        meta_window_move_to_monitor (surface->window, output->logical_monitor->number);
+        meta_window_move_to_monitor (window, output->logical_monitor->number);
     }
 
-  meta_window_make_fullscreen (surface->window);
+  meta_window_make_fullscreen (window);
 }
 
 static void
@@ -387,8 +442,13 @@ zxdg_toplevel_v6_unset_fullscreen (struct wl_client   *client,
                                    struct wl_resource *resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
 
-  meta_window_unmake_fullscreen (surface->window);
+  window = surface->window;
+  if (!window)
+    return;
+
+  meta_window_unmake_fullscreen (window);
 }
 
 static void
@@ -396,8 +456,13 @@ zxdg_toplevel_v6_set_minimized (struct wl_client   *client,
                                 struct wl_resource *resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
 
-  meta_window_minimize (surface->window);
+  window = surface->window;
+  if (!window)
+    return;
+
+  meta_window_minimize (window);
 }
 
 static const struct zxdg_toplevel_v6_interface meta_wayland_zxdg_toplevel_v6_interface = {