xdg-foreign-v2: return wlr_xdg_toplevel in verify_is_toplevel()

This makes it clearer that the wlr_xdg_toplevel cannot be NULL.

types/wlr_xdg_foreign_v2.c

@@ -27,28 +27,28 @@ static void xdg_imported_handle_destroy(struct wl_client *client,
 	wl_resource_destroy(resource);
 }
 
-static bool verify_is_toplevel(struct wl_resource *client_resource,
+static struct wlr_xdg_toplevel *verify_is_toplevel(struct wl_resource *resource,
 		struct wlr_surface *surface) {
 	// Note: the error codes are the same for zxdg_exporter_v2 and
 	// zxdg_importer_v2
 
 	if (!wlr_surface_is_xdg_surface(surface)) {
-		wl_resource_post_error(client_resource,
+		wl_resource_post_error(resource,
 			ZXDG_EXPORTER_V2_ERROR_INVALID_SURFACE,
 			"surface must be an xdg_surface");
-		return false;
+		return NULL;
 	}
 
 	struct wlr_xdg_surface *xdg_surface =
 		wlr_xdg_surface_from_wlr_surface(surface);
 	if (xdg_surface == NULL || xdg_surface->role != WLR_XDG_SURFACE_ROLE_TOPLEVEL) {
-		wl_resource_post_error(client_resource,
+		wl_resource_post_error(resource,
 			ZXDG_EXPORTER_V2_ERROR_INVALID_SURFACE,
 			"surface must be an xdg_toplevel");
-		return false;
+		return NULL;
 	}
 
-	return true;
+	return xdg_surface->toplevel;
 }
 
 static void destroy_imported_child(struct wlr_xdg_imported_child_v2 *child) {
@@ -84,17 +84,16 @@ static void xdg_imported_handle_set_parent_of(struct wl_client *client,
 	struct wlr_surface *wlr_surface_child =
 		wlr_surface_from_resource(child_resource);
 
-	if (!verify_is_toplevel(resource, wlr_surface_child)) {
-		return;
-	}
-
 	struct wlr_xdg_surface *surface =
 		wlr_xdg_surface_from_wlr_surface(wlr_surface);
-	struct wlr_xdg_surface *surface_child =
-		wlr_xdg_surface_from_wlr_surface(wlr_surface_child);
+	struct wlr_xdg_toplevel *child_toplevel =
+		verify_is_toplevel(resource, wlr_surface_child);
+	if (!child_toplevel) {
+		return;
+	}
 
 	if (!surface->mapped) {
-		wlr_xdg_toplevel_set_parent(surface_child->toplevel, NULL);
+		wlr_xdg_toplevel_set_parent(child_toplevel, NULL);
 		return;
 	}
 
@@ -114,10 +113,10 @@ static void xdg_imported_handle_set_parent_of(struct wl_client *client,
 	child->xdg_surface_unmap.notify = handle_child_xdg_surface_unmap;
 	child->xdg_toplevel_set_parent.notify = handle_xdg_toplevel_set_parent;
 
-	wlr_xdg_toplevel_set_parent(surface_child->toplevel, surface->toplevel);
-	wl_signal_add(&surface_child->events.unmap,
+	wlr_xdg_toplevel_set_parent(child_toplevel, surface->toplevel);
+	wl_signal_add(&child_toplevel->base->events.unmap,
 			&child->xdg_surface_unmap);
-	wl_signal_add(&surface_child->toplevel->events.set_parent,
+	wl_signal_add(&child_toplevel->events.set_parent,
 			&child->xdg_toplevel_set_parent);
 
 	wl_list_insert(&imported->children, &child->link);
@@ -209,7 +208,9 @@ static void xdg_exporter_handle_export(struct wl_client *wl_client,
 		xdg_foreign_from_exporter_resource(client_resource);
 	struct wlr_surface *surface = wlr_surface_from_resource(surface_resource);
 
-	if (!verify_is_toplevel(client_resource, surface)) {
+	struct wlr_xdg_toplevel *xdg_toplevel =
+		verify_is_toplevel(client_resource, surface);
+	if (!xdg_toplevel) {
 		return;
 	}
 
@@ -244,9 +245,7 @@ static void xdg_exporter_handle_export(struct wl_client *wl_client,
 	zxdg_exported_v2_send_handle(exported->resource, exported->base.handle);
 
 	exported->xdg_surface_unmap.notify = handle_xdg_surface_unmap;
-	struct wlr_xdg_surface *xdg_surface =
-		wlr_xdg_surface_from_wlr_surface(surface);
-	wl_signal_add(&xdg_surface->events.unmap, &exported->xdg_surface_unmap);
+	wl_signal_add(&xdg_toplevel->base->events.unmap, &exported->xdg_surface_unmap);
 }
 
 static const struct zxdg_exporter_v2_interface xdg_exporter_impl = {