tests/wayland-test-clients: Reuse surface for XDG toplevels

It's possible to destory the xdg_toplevel and xdg_surface which removes
the surface role and then re-use the surface on a new toplevel.

Mutter used to not create new SurfaceActors for the new toplevel which
were then shared between the old and new toplevel. This happens because
the actors can stay around after the wl resource is destroyed (e.g. for
closing effects).

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3667>

src/tests/wayland-test-clients/meson.build

@@ -66,6 +66,9 @@ wayland_test_clients = [
   {
     'name': 'subsurface-reparenting',
   },
+  {
+    'name': 'toplevel-reuse-surface',
+  },
   {
     'name': 'toplevel-show-states',
   },

src/tests/wayland-test-clients/toplevel-reuse-surface.c

@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2019 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <glib.h>
+#include <wayland-client.h>
+
+#include "wayland-test-client-utils.h"
+
+typedef enum _State
+{
+  STATE_INIT = 0,
+  STATE_WAIT_FOR_CONFIGURE_1,
+  STATE_WAIT_FOR_CONFIGURE_2,
+  STATE_WAIT_FOR_EFFECTS,
+  STATE_DONE,
+} State;
+
+typedef struct _TestWindow
+{
+  WaylandDisplay *display;
+  struct wl_surface *wl_surface;
+  struct xdg_surface *xdg_surface;
+  struct xdg_toplevel *xdg_toplevel;
+  State state;
+} TestWindow;
+
+static void
+handle_xdg_surface_configure (void               *data,
+                              struct xdg_surface *xdg_surface,
+                              uint32_t            serial);
+
+static const struct xdg_surface_listener xdg_surface_listener = {
+  handle_xdg_surface_configure,
+};
+
+static void
+handle_xdg_surface_configure (void               *data,
+                              struct xdg_surface *xdg_surface,
+                              uint32_t            serial)
+{
+  TestWindow *window = data;
+  WaylandDisplay *display = window->display;
+
+  switch (window->state)
+    {
+    case STATE_WAIT_FOR_CONFIGURE_1:
+      draw_surface (display, window->wl_surface, 700, 500, 0xff00ff00);
+      xdg_surface_ack_configure (window->xdg_surface, serial);
+      wl_surface_commit (window->wl_surface);
+
+      window->state = STATE_WAIT_FOR_EFFECTS;
+      wait_for_effects_completed (display, window->wl_surface);
+
+      xdg_toplevel_destroy (window->xdg_toplevel);
+      xdg_surface_destroy (window->xdg_surface);
+      wl_surface_attach (window->wl_surface, NULL, 0, 0);
+      wl_surface_commit (window->wl_surface);
+      window->xdg_surface =
+        xdg_wm_base_get_xdg_surface (display->xdg_wm_base, window->wl_surface);
+      xdg_surface_add_listener (window->xdg_surface,
+                                &xdg_surface_listener, window);
+      window->xdg_toplevel = xdg_surface_get_toplevel (window->xdg_surface);
+      xdg_toplevel_set_title (window->xdg_toplevel,
+                              "toplevel-reuse-surface-test");
+      wl_surface_commit (window->wl_surface);
+      window->state = STATE_WAIT_FOR_CONFIGURE_2;
+      break;
+    case STATE_WAIT_FOR_CONFIGURE_2:
+      draw_surface (display, window->wl_surface, 700, 500, 0xff00ff00);
+      xdg_surface_ack_configure (window->xdg_surface, serial);
+      wl_surface_commit (window->wl_surface);
+
+      window->state = STATE_WAIT_FOR_EFFECTS;
+      wait_for_effects_completed (display, window->wl_surface);
+
+      window->state = STATE_DONE;
+      break;
+    default:
+      break;
+    }
+}
+
+int
+main (int    argc,
+      char **argv)
+{
+  g_autoptr (WaylandDisplay) display = NULL;
+  TestWindow window;
+
+  display = wayland_display_new (WAYLAND_DISPLAY_CAPABILITY_TEST_DRIVER);
+  window.display = display;
+
+  window.wl_surface = wl_compositor_create_surface (display->compositor);
+  window.xdg_surface = xdg_wm_base_get_xdg_surface (display->xdg_wm_base,
+                                                    window.wl_surface);
+  xdg_surface_add_listener (window.xdg_surface, &xdg_surface_listener, &window);
+  window.xdg_toplevel = xdg_surface_get_toplevel (window.xdg_surface);
+
+  xdg_toplevel_set_title (window.xdg_toplevel,
+                          "toplevel-reuse-surface-test");
+  wl_surface_commit (window.wl_surface);
+
+  window.state = STATE_WAIT_FOR_CONFIGURE_1;
+
+  while (window.state != STATE_DONE)
+    {
+      if (wl_display_dispatch (display->display) == -1)
+        return EXIT_FAILURE;
+    }
+
+  return EXIT_SUCCESS;
+}

src/tests/wayland-unit-tests.c

@@ -562,6 +562,16 @@ toplevel_activation (void)
   meta_wayland_test_client_finish (wayland_test_client);
 }
 
+static void
+toplevel_reuse_surface (void)
+{
+  MetaWaylandTestClient *wayland_test_client;
+
+  wayland_test_client =
+    meta_wayland_test_client_new (test_context, "toplevel-reuse-surface");
+  meta_wayland_test_client_finish (wayland_test_client);
+}
+
 static gboolean
 mark_later_as_done (gpointer user_data)
 {
@@ -1039,6 +1049,8 @@ init_tests (void)
   g_test_add_func ("/wayland/toplevel/bounds/monitors",
                    toplevel_bounds_monitors);
 #endif
+  g_test_add_func ("/wayland/toplevel/reuse-surface",
+                   toplevel_reuse_surface);
   g_test_add_func ("/wayland/xdg-foreign/set-parent-of",
                    xdg_foreign_set_parent_of);
   g_test_add_func ("/wayland/toplevel/show-states",