tests/async-waiter: Keep track of X11 display it was created with

The Xwayland server can go away at any time; when this happen we might
have a test client running, and for it to tear down more nicely, make
sure to avoid trying to clean up X11 resources on the old X11 display.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2364>

src/tests/meta-test-utils.c

@@ -50,7 +50,10 @@ struct _MetaTestClient
   MetaAsyncWaiter *waiter;
 };
 
-struct _MetaAsyncWaiter {
+struct _MetaAsyncWaiter
+{
+  MetaX11Display *x11_display;
+
   XSyncCounter counter;
   int counter_value;
   XSyncAlarm alarm;
@@ -91,15 +94,18 @@ meta_ensure_test_client_path (int    argc,
 }
 
 MetaAsyncWaiter *
-meta_async_waiter_new (void)
+meta_async_waiter_new (MetaX11Display *x11_display)
 {
-  MetaAsyncWaiter *waiter = g_new0 (MetaAsyncWaiter, 1);
-
-  MetaDisplay *display = meta_get_display ();
-  Display *xdisplay = display->x11_display->xdisplay;
+  Display *xdisplay = meta_x11_display_get_xdisplay (x11_display);
+  MetaAsyncWaiter *waiter;
   XSyncValue value;
   XSyncAlarmAttributes attr;
 
+  waiter = g_new0 (MetaAsyncWaiter, 1);
+
+  waiter->x11_display = x11_display;
+  g_object_add_weak_pointer (G_OBJECT (x11_display),
+                             (gpointer *) &waiter->x11_display);
   waiter->counter_value = 0;
   XSyncIntToValue (&value, waiter->counter_value);
 
@@ -136,11 +142,19 @@ meta_async_waiter_new (void)
 void
 meta_async_waiter_destroy (MetaAsyncWaiter *waiter)
 {
-  MetaDisplay *display = meta_get_display ();
-  Display *xdisplay = display->x11_display->xdisplay;
+  MetaX11Display *x11_display;
 
-  XSyncDestroyAlarm (xdisplay, waiter->alarm);
-  XSyncDestroyCounter (xdisplay, waiter->counter);
+  x11_display = waiter->x11_display;
+  if (x11_display)
+    {
+      Display *xdisplay = meta_x11_display_get_xdisplay (x11_display);
+
+      XSyncDestroyAlarm (xdisplay, waiter->alarm);
+      XSyncDestroyCounter (xdisplay, waiter->counter);
+
+      g_object_remove_weak_pointer (G_OBJECT (x11_display),
+                                    (gpointer *) &waiter->x11_display);
+    }
   g_main_loop_unref (waiter->loop);
 }
 
@@ -165,13 +179,17 @@ meta_async_waiter_wait (MetaAsyncWaiter *waiter,
 void
 meta_async_waiter_set_and_wait (MetaAsyncWaiter *waiter)
 {
-  MetaDisplay *display = meta_get_display ();
-  Display *xdisplay = display->x11_display->xdisplay;
-  int wait_value = meta_async_waiter_next_value (waiter);
+  Display *xdisplay;
+  int wait_value;
+
+  g_return_if_fail (waiter->x11_display);
+
+  wait_value = meta_async_waiter_next_value (waiter);
 
   XSyncValue sync_value;
   XSyncIntToValue (&sync_value, wait_value);
 
+  xdisplay = meta_x11_display_get_xdisplay (waiter->x11_display);
   XSyncSetCounter (xdisplay, waiter->counter, sync_value);
   meta_async_waiter_wait (waiter, wait_value);
 }
@@ -181,6 +199,7 @@ meta_async_waiter_process_x11_event (MetaAsyncWaiter       *waiter,
                                      MetaX11Display        *x11_display,
                                      XSyncAlarmNotifyEvent *event)
 {
+  g_assert (x11_display == waiter->x11_display);
 
   if (event->alarm != waiter->alarm)
     return FALSE;
@@ -520,9 +539,11 @@ meta_test_client_new (MetaContext           *context,
 
   if (client->type == META_WINDOW_CLIENT_TYPE_X11)
     {
-      MetaDisplay *display = meta_get_display ();
+      MetaDisplay *display = meta_context_get_display (context);
+      MetaX11Display *x11_display;
 
-      if (!display->x11_display)
+      x11_display = meta_display_get_x11_display (display);
+      if (!x11_display)
         {
           GThread *thread;
 
@@ -532,8 +553,10 @@ meta_test_client_new (MetaContext           *context,
           meta_context_test_wait_for_x11_display (META_CONTEXT_TEST (context));
           g_thread_join (thread);
         }
+      x11_display = meta_display_get_x11_display (display);
+      g_assert_nonnull (x11_display);
 
-      client->waiter = meta_async_waiter_new ();
+      client->waiter = meta_async_waiter_new (x11_display);
     }
 
   return client;

src/tests/meta-test-utils.h

@@ -50,14 +50,14 @@ typedef struct _MetaTestClient MetaTestClient;
 
 META_EXPORT
 gboolean meta_async_waiter_process_x11_event (MetaAsyncWaiter       *waiter,
-                                              MetaX11Display        *display,
+                                              MetaX11Display        *x11_display,
                                               XSyncAlarmNotifyEvent *event);
 
 META_EXPORT
 void meta_async_waiter_set_and_wait (MetaAsyncWaiter *waiter);
 
 META_EXPORT
-MetaAsyncWaiter * meta_async_waiter_new (void);
+MetaAsyncWaiter * meta_async_waiter_new (MetaX11Display *x11_display);
 
 META_EXPORT
 void meta_async_waiter_destroy (MetaAsyncWaiter *waiter);

src/tests/test-runner.c

@@ -73,7 +73,7 @@ on_x11_display_opened (MetaDisplay *display,
 {
   meta_x11_display_set_alarm_filter (display->x11_display,
                                      test_case_alarm_filter, test);
-  test->waiter = meta_async_waiter_new ();
+  test->waiter = meta_async_waiter_new (display->x11_display);
 }
 
 static TestCase *