x11: Add a destroy listener for X11 surfaces

compositor/shell.c

@@ -952,6 +952,7 @@ shell_init(struct wlsc_compositor *ec)
 	if (shell == NULL)
 		return -1;
 
+	memset(shell, 0, sizeof *shell);
 	shell->compositor = ec;
 	shell->shell.activate = activate;
 	shell->shell.lock = lock;

compositor/xserver-launcher.c

@@ -87,6 +87,7 @@ struct wlsc_wm {
 struct wlsc_wm_window {
 	xcb_window_t id;
 	struct wlsc_surface *surface;
+	struct wl_listener surface_destroy_listener;
 };
 
 static void
@@ -567,6 +568,17 @@ wlsc_xserver_cleanup(struct wlsc_process *process, int status)
 	}
 }
 
+static void
+surface_destroy(struct wl_listener *listener,
+		struct wl_resource *resource, uint32_t time)
+{
+	struct wlsc_wm_window *window =
+		container_of(listener,
+			     struct wlsc_wm_window, surface_destroy_listener);
+
+	fprintf(stderr, "surface for xid %d destroyed\n", window->id);
+}
+
 static void
 xserver_set_window_id(struct wl_client *client, struct wl_resource *resource,
 		      struct wl_resource *surface_resource, uint32_t id)
@@ -588,7 +600,9 @@ xserver_set_window_id(struct wl_client *client, struct wl_resource *resource,
 	fprintf(stderr, "set_window_id %d for surface %p\n", id, surface);
 
 	window->surface = (struct wlsc_surface *) surface;
-	/* FIXME: Do we need a surface destroy listener? */
+	window->surface_destroy_listener.func = surface_destroy;
+	wl_list_insert(surface->resource.destroy_listener_list.prev,
+		       &window->surface_destroy_listener.link);
 }
 
 static const struct xserver_interface xserver_implementation = {