xdg-activation: distinguish activation and urgency requests

Check if the app that requested a token has provided a valid input
serial and a focused surface. Downgrade activation request to urgency
otherwise.

This is mostly in line with what other Wayland compositors decided to
do, and offers a better security than the original logic.

(cherry picked from commit d19810eba8)

include/sway/desktop/launcher.h

@@ -14,6 +14,7 @@ struct launcher_ctx {
 	struct wl_listener seat_destroy;
 
 	bool activated;
+	bool had_focused_surface;
 
 	struct sway_node *node;
 	struct wl_listener node_destroy;

include/sway/tree/view.h

@@ -277,6 +277,11 @@ void view_set_activated(struct sway_view *view, bool activated);
  */
 void view_request_activate(struct sway_view *view, struct sway_seat *seat);
 
+/*
+ * Called when the view requests urgent state
+ */
+void view_request_urgent(struct sway_view *view);
+
 /**
  * If possible, instructs the client to change their decoration mode.
  */

sway/desktop/launcher.c

@@ -216,6 +216,8 @@ struct launcher_ctx *launcher_ctx_create(struct wlr_xdg_activation_token_v1 *tok
 	ctx->fallback_name = strdup(fallback_name);
 	ctx->token = token;
 	ctx->node = node;
+	// Having surface set means that the focus check in wlroots has passed
+	ctx->had_focused_surface = token->surface != NULL;
 
 	ctx->node_destroy.notify = ctx_handle_node_destroy;
 	wl_signal_add(&ctx->node->events.destroy, &ctx->node_destroy);

sway/tree/view.c

@@ -399,6 +399,12 @@ void view_request_activate(struct sway_view *view, struct sway_seat *seat) {
 	transaction_commit_dirty();
 }
 
+void view_request_urgent(struct sway_view *view) {
+	if (config->focus_on_window_activation != FOWA_NONE) {
+		view_set_urgent(view, true);
+	}
+}
+
 void view_set_csd_from_server(struct sway_view *view, bool enabled) {
 	sway_log(SWAY_DEBUG, "Telling view %p to set CSD to %i", view, enabled);
 	if (view->xdg_decoration) {

sway/xdg_activation_v1.c

@@ -43,8 +43,11 @@ void xdg_activation_v1_handle_request_activate(struct wl_listener *listener,
 		seat = ctx->token->seat ? ctx->token->seat->data : NULL;
 	}
 
-	if (seat) {
+	if (seat && ctx->had_focused_surface) {
 		view_request_activate(view, seat);
+	} else {
+		// The token is valid, but cannot be used to activate a window
+		view_request_urgent(view);
 	}
 }