Prevent duplicate workspace::focus events

Previously we would compare the last focus's workspace with the new
focus's workspace to determine if we need to emit an IPC
workspace::focus event. This doesn't work when moving the focused
container to a new workspace.

This adds a workspace property to the seat which stores the last emitted
workspace::focus workspace. Using this method, after moving the
container, refocusing it will trigger exactly one workspace::focus
event: from the old workspace to the new workspace.

include/sway/input/seat.h

@@ -51,6 +51,7 @@ struct sway_seat {
 
 	bool has_focus;
 	struct wl_list focus_stack; // list of containers in focus order
+	struct sway_workspace *workspace;
 
 	// If the focused layer is set, views cannot receive keyboard focus
 	struct wlr_layer_surface_v1 *focused_layer;

sway/commands/move.c

@@ -704,7 +704,7 @@ static struct cmd_results *cmd_move_in_direction(
 	}
 
 	// Hack to re-focus container
-	seat_set_focus_workspace(config->handler_context.seat, new_ws);
+	seat_set_raw_focus(config->handler_context.seat, &new_ws->node);
 	seat_set_focus_container(config->handler_context.seat, container);
 
 	if (old_ws != new_ws) {

sway/input/seat.c

@@ -623,6 +623,15 @@ static void container_raise_floating(struct sway_container *con) {
 	}
 }
 
+static void set_workspace(struct sway_seat *seat,
+		struct sway_workspace *new_ws) {
+	if (seat->workspace == new_ws) {
+		return;
+	}
+	ipc_event_workspace(seat->workspace, new_ws, "focus");
+	seat->workspace = new_ws;
+}
+
 void seat_set_raw_focus(struct sway_seat *seat, struct sway_node *node) {
 	struct sway_seat_node *seat_node = seat_node_from_node(seat, node);
 	wl_list_remove(&seat_node->link);
@@ -709,9 +718,7 @@ void seat_set_focus_warp(struct sway_seat *seat, struct sway_node *node,
 	}
 
 	// emit ipc events
-	if (new_workspace && last_workspace != new_workspace) {
-		 ipc_event_workspace(last_workspace, new_workspace, "focus");
-	}
+	set_workspace(seat, new_workspace);
 	if (container && container->view) {
 		ipc_event_window(container, "focus");
 	}