use bfs iterator to collect focus stack

include/sway/container.h

@@ -163,9 +163,9 @@ swayc_t *swayc_at(swayc_t *parent, double lx, double ly,
 		struct wlr_surface **surface, double *sx, double *sy);
 
 /**
- * Get a list of containers that are descendents of the container in rendering
- * order
+ * Apply the function for each child of the container breadth first.
  */
-list_t *container_list_children(swayc_t *con);
+void container_for_each_bfs(swayc_t *con, void (*f)(swayc_t *con, void *data),
+		void *data);
 
 #endif

sway/input/seat.c

@@ -70,6 +70,20 @@ static void handle_new_container(struct wl_listener *listener, void *data) {
 	seat_container_from_container(seat, con);
 }
 
+static void collect_focus_iter(swayc_t *con, void *data) {
+	struct sway_seat *seat = data;
+	if (con->type > C_WORKSPACE) {
+		return;
+	}
+	struct sway_seat_container *seat_con =
+		seat_container_from_container(seat, con);
+	if (!seat_con) {
+		return;
+	}
+	wl_list_remove(&seat_con->link);
+	wl_list_insert(&seat->focus_stack, &seat_con->link);
+}
+
 struct sway_seat *sway_seat_create(struct sway_input_manager *input,
 		const char *seat_name) {
 	struct sway_seat *seat = calloc(1, sizeof(struct sway_seat));
@@ -92,17 +106,8 @@ struct sway_seat *sway_seat_create(struct sway_input_manager *input,
 
 	// init the focus stack
 	wl_list_init(&seat->focus_stack);
-	list_t *containers = container_list_children(&root_container);
-	if (containers == NULL) {
-		wlr_seat_destroy(seat->wlr_seat);
-		free(seat);
-		return NULL;
-	}
-	for (int i = containers->length - 1; i >= 0; --i) {
-		swayc_t *con = containers->items[i];
-		seat_container_from_container(seat, con);
-	}
-	free(containers);
+
+	container_for_each_bfs(&root_container, collect_focus_iter, seat);
 
 	wl_signal_add(&root_container.sway_root->events.new_container,
 		&seat->new_container);

sway/tree/container.c

@@ -381,13 +381,13 @@ void container_map(swayc_t *container, void (*f)(swayc_t *view, void *data), voi
 	}
 }
 
-/**
- * Get a list of containers that are descendents of the container in rendering
- * order
- */
-list_t *container_list_children(swayc_t *con) {
-	list_t *list = create_list();
+void container_for_each_bfs(swayc_t *con, void (*f)(swayc_t *con, void *data),
+		void *data) {
 	list_t *queue = create_list();
+	if (queue == NULL) {
+		wlr_log(L_ERROR, "could not allocate list");
+		return;
+	}
 
 	list_add(queue, con);
 
@@ -395,11 +395,10 @@ list_t *container_list_children(swayc_t *con) {
 	while (queue->length) {
 		current = queue->items[0];
 		list_del(queue, 0);
-		list_add(list, current);
+		f(current, data);
 		// TODO floating containers
 		list_cat(queue, current->children);
 	}
 
 	list_free(queue);
-	return list;
 }