shell/tray-manager: Only create resources when needed

NaTrayManager in particular is deeply tied to X11. We currently assume
that X11 support is always available, but that is already not true
anymore - Xwayland startup is now asynchronous.

It will be even less true once we handle Xwayland crashes gracefully.

Start addressing that by not creating the corresponding resources once
and assume they exist for the lifetime of Shell.TrayManager, but make
sure they exist when actually needed.

https://gitlab.gnome.org/GNOME/gnome-shell/issues/2308

diff --git a/src/shell-tray-manager.c b/src/shell-tray-manager.c
index 6503cc3c45db2bdc666e34b386c432776e46ecc6..269682bcffecd28a297189e1accc08aeafb9a416 100644 (file)
--- a/src/shell-tray-manager.c
+++ b/src/shell-tray-manager.c
@@ -58,6 +58,8 @@ static guint shell_tray_manager_signals [LAST_SIGNAL] = { 0 };
 
 static const ClutterColor default_color = { 0x00, 0x00, 0x00, 0xff };
 
+static void shell_tray_manager_release_resources (ShellTrayManager *manager);
+
 static void na_tray_icon_added (NaTrayManager *na_manager, GtkWidget *child, gpointer manager);
 static void na_tray_icon_removed (NaTrayManager *na_manager, GtkWidget *child, gpointer manager);
 
@@ -125,16 +127,7 @@ shell_tray_manager_init (ShellTrayManager *manager)
 {
   manager->priv = shell_tray_manager_get_instance_private (manager);
 
-  manager->priv->na_manager = na_tray_manager_new ();
-
-  manager->priv->icons = g_hash_table_new_full (NULL, NULL,
-                                                NULL, free_tray_icon);
   manager->priv->bg_color = default_color;
-
-  g_signal_connect (manager->priv->na_manager, "tray-icon-added",
-                    G_CALLBACK (na_tray_icon_added), manager);
-  g_signal_connect (manager->priv->na_manager, "tray-icon-removed",
-                    G_CALLBACK (na_tray_icon_removed), manager);
 }
 
 static void
@@ -142,8 +135,7 @@ shell_tray_manager_finalize (GObject *object)
 {
   ShellTrayManager *manager = SHELL_TRAY_MANAGER (object);
 
-  g_object_unref (manager->priv->na_manager);
-  g_hash_table_destroy (manager->priv->icons);
+  shell_tray_manager_release_resources (manager);
 
   G_OBJECT_CLASS (shell_tray_manager_parent_class)->finalize (object);
 }
@@ -193,6 +185,30 @@ shell_tray_manager_new (void)
   return g_object_new (SHELL_TYPE_TRAY_MANAGER, NULL);
 }
 
+static void
+shell_tray_manager_ensure_resources (ShellTrayManager *manager)
+{
+  if (manager->priv->na_manager != NULL)
+    return;
+
+  manager->priv->icons = g_hash_table_new_full (NULL, NULL,
+                                                NULL, free_tray_icon);
+
+  manager->priv->na_manager = na_tray_manager_new ();
+
+  g_signal_connect (manager->priv->na_manager, "tray-icon-added",
+                    G_CALLBACK (na_tray_icon_added), manager);
+  g_signal_connect (manager->priv->na_manager, "tray-icon-removed",
+                    G_CALLBACK (na_tray_icon_removed), manager);
+}
+
+static void
+shell_tray_manager_release_resources (ShellTrayManager *manager)
+{
+  g_clear_object (&manager->priv->na_manager);
+  g_clear_pointer (&manager->priv->icons, g_hash_table_destroy);
+}
+
 static void
 shell_tray_manager_style_changed (StWidget *theme_widget,
                                   gpointer  user_data)
@@ -212,6 +228,8 @@ void
 shell_tray_manager_manage_screen (ShellTrayManager *manager,
                                   StWidget         *theme_widget)
 {
+  shell_tray_manager_ensure_resources (manager);
+
   na_tray_manager_manage_screen (manager->priv->na_manager);
 
   g_signal_connect_object (theme_widget, "style-changed",