Make focus part of transactions

Rather than maintain copies of the entire focus stack, this PR
transactionises the focus by introducing two new properties to the
container state and using those when rendering.

* `bool focused` means this container has actual focus. Only one
container should have this equalling true in its current state.
* `struct sway_container *focus_inactive_child` points to the immediate
child that was most recently focused (eg. for tabbed and stacked
containers).

1 files changed, 6 insertions, 18 deletions

diff --git a/sway/input/seat.c b/sway/input/seat.c
index 5e65ca70..74f1375e 100644
--- a/sway/input/seat.c
+++ b/sway/input/seat.c
@@ -661,9 +661,13 @@ void seat_set_focus_warp(struct sway_seat *seat,
 		if (last_focus) {
 			seat_send_unfocus(last_focus, seat);
 		}
-
 		seat_send_focus(container, seat);
-		container_damage_whole(container->parent);
+
+		container_set_dirty(container);
+		container_set_dirty(container->parent); // for focused_inactive_child
+		if (last_focus) {
+			container_set_dirty(last_focus);
+		}
 	}
 
 	// If we've focused a floating container, bring it to the front.
@@ -717,10 +721,6 @@ void seat_set_focus_warp(struct sway_seat *seat,
 		}
 	}
 
-	if (last_focus) {
-		container_damage_whole(last_focus);
-	}
-
 	if (last_workspace && last_workspace != new_workspace) {
 		cursor_send_pointer_motion(seat->cursor, 0, true);
 	}
@@ -840,18 +840,6 @@ struct sway_container *seat_get_active_child(struct sway_seat *seat,
 	return NULL;
 }
 
-struct sway_container *seat_get_active_current_child(struct sway_seat *seat,
-		struct sway_container *container) {
-	struct sway_seat_container *current = NULL;
-	wl_list_for_each(current, &seat->focus_stack, link) {
-		if (current->container->current.parent == container &&
-				current->container->current.layout != L_FLOATING) {
-			return current->container;
-		}
-	}
-	return NULL;
-}
-
 struct sway_container *seat_get_focus(struct sway_seat *seat) {
 	if (!seat->has_focus) {
 		return NULL;