[gnome-shell/wip/iainl/sd-notify-later] main, util: Notify systemd once we are fully initialised

[Iain Lane <iainl src gnome org>]

commit 47b03eaa6b94027845d8cf8294c967af4e82a217
Author: Iain Lane <iainl gnome org>
Date:   Fri Oct 4 12:11:06 2019 +0100

    main, util: Notify systemd once we are fully initialised
    
    If graphical applications want to start from systemd units, they need to
    start after we're properly ready to display them. This is particularly
    important under X where `_GTK_FRAME_EXTENTS` and other xprops are needed
    to have the right theming.
    
    We're doing this in an idle callback so that the dynamic starting of
    `gnome-session-x11-service.target` (which launches `gsd-xsettings`) as
    the result of a signal emission happens before us signalling we're ready
    for later things to start.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/750

 js/ui/main.js    |  6 +++++-
 src/main.c       | 11 -----------
 src/shell-util.c | 16 ++++++++++++++++
 src/shell-util.h |  2 ++
 4 files changed, 23 insertions(+), 12 deletions(-)
---
diff --git a/js/ui/main.js b/js/ui/main.js
index e8269f09be..17f5bc716d 100644
--- a/js/ui/main.js
+++ b/js/ui/main.js
@@ -229,7 +229,11 @@ function _initializeUI() {
     EndSessionDialog.init();
 
     // We're ready for the session manager to move to the next phase
-    Meta.register_with_session();
+    GLib.idle_add(GLib.PRIORITY_DEFAULT, () => {
+        Shell.util_sd_notify();
+        Meta.register_with_session();
+        return GLib.SOURCE_REMOVE;
+    });
 
     _startDate = new Date();
 
diff --git a/src/main.c b/src/main.c
index 489026b765..6faf9934fb 100644
--- a/src/main.c
+++ b/src/main.c
@@ -24,14 +24,6 @@
 #include "shell-perf-log.h"
 #include "st.h"
 
-#ifdef HAVE_SYSTEMD
-#include <systemd/sd-daemon.h>
-#else
-/* So we don't need to add ifdef's everywhere */
-#define sd_notify(u, m)            do {} while (0)
-#define sd_notifyf(u, m, ...)      do {} while (0)
-#endif
-
 extern GType gnome_shell_plugin_get_type (void);
 
 #define SHELL_DBUS_SERVICE "org.gnome.Shell"
@@ -532,9 +524,6 @@ main (int argc, char **argv)
   shell_init_debug (g_getenv ("SHELL_DEBUG"));
 
   shell_dbus_init (meta_get_replace_current_wm ());
-  /* We only use NOTIFY_SOCKET exactly once; unset it so it doesn't remain in
-   * our environment. */
-  sd_notify (1, "READY=1");
   shell_a11y_init ();
   shell_perf_log_init ();
   shell_introspection_init ();
diff --git a/src/shell-util.c b/src/shell-util.c
index c22dd1c6e5..f93462c73e 100644
--- a/src/shell-util.c
+++ b/src/shell-util.c
@@ -26,6 +26,14 @@
 #include <langinfo.h>
 #endif
 
+#ifdef HAVE_SYSTEMD
+#include <systemd/sd-daemon.h>
+#else
+/* So we don't need to add ifdef's everywhere */
+#define sd_notify(u, m)            do {} while (0)
+#define sd_notifyf(u, m, ...)      do {} while (0)
+#endif
+
 static void
 stop_pick (ClutterActor       *actor,
            const ClutterColor *color)
@@ -659,3 +667,11 @@ shell_util_stop_systemd_unit (const char  *unit,
 {
   return shell_util_systemd_call ("StopUnit", unit, mode, error);
 }
+
+void
+shell_util_sd_notify (void)
+{
+  /* We only use NOTIFY_SOCKET exactly once; unset it so it doesn't remain in
+   * our environment. */
+  sd_notify (1, "READY=1");
+}
diff --git a/src/shell-util.h b/src/shell-util.h
index c41e02c798..4453beb4a5 100644
--- a/src/shell-util.h
+++ b/src/shell-util.h
@@ -66,6 +66,8 @@ gboolean shell_util_stop_systemd_unit  (const char  *unit,
                                         const char  *mode,
                                         GError     **error);
 
+void shell_util_sd_notify (void);
+
 G_END_DECLS
 
 #endif /* __SHELL_UTIL_H__ */