[gnome-settings-daemon/wip/laney/systemd-user: 27/29] common: Have plugins claim a name on the bus when they are ready

[Iain Lane <iainl src gnome org>]

commit 7298ea31c89c9b38fc4b416e6739542f20fa1dac
Author: Iain Lane <iain orangesquash org uk>
Date:   Fri Dec 15 15:03:55 2017 +0000

    common: Have plugins claim a name on the bus when they are ready
    
    The plugins are about to switch to being activated by systemd. We need a
    way for them to signal to systemd when they are ready. We'd like to
    avoid linking to libsystemd, so sd_notify() is out - let's have the
    plugins claim a name on the bus and then we can create Type=dbus units.

 plugins/common/daemon-skeleton-gtk.h | 36 ++++++++++++++++++++++++++++++++
 plugins/common/daemon-skeleton.h     | 40 ++++++++++++++++++++++++++++++++++++
 plugins/meson.build                  |  2 ++
 3 files changed, 78 insertions(+)
---
diff --git a/plugins/common/daemon-skeleton-gtk.h b/plugins/common/daemon-skeleton-gtk.h
index 49c7ad5d..ab5c7833 100644
--- a/plugins/common/daemon-skeleton-gtk.h
+++ b/plugins/common/daemon-skeleton-gtk.h
@@ -187,10 +187,35 @@ set_empty_gtk_theme (gboolean set)
        }
 }
 
+static void
+bus_acquired_cb (GDBusConnection *connection,
+                 const gchar *name,
+                 gpointer user_data G_GNUC_UNUSED)
+{
+        g_debug ("%s: acquired bus %p for name %s", G_STRFUNC, connection, name);
+}
+
+static void
+name_acquired_cb (GDBusConnection *connection,
+                  const gchar *name,
+                  gpointer user_data G_GNUC_UNUSED)
+{
+        g_debug ("%s: acquired name %s on bus %p", G_STRFUNC, name, connection);
+}
+
+static void
+name_lost_cb (GDBusConnection *connection,
+              const gchar *name,
+              gpointer user_data G_GNUC_UNUSED)
+{
+        g_debug ("%s: lost name %s on bus %p", G_STRFUNC, name, connection);
+}
+
 int
 main (int argc, char **argv)
 {
         GError  *error;
+        guint name_own_id;
 
         bindtextdomain (GETTEXT_PACKAGE, GNOME_SETTINGS_LOCALEDIR);
         bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
@@ -245,11 +270,22 @@ main (int argc, char **argv)
                }
        }
 
+       name_own_id = g_bus_own_name (G_BUS_TYPE_SESSION,
+                                     PLUGIN_DBUS_NAME,
+                                     G_BUS_NAME_OWNER_FLAGS_DO_NOT_QUEUE,
+                                     bus_acquired_cb,
+                                     name_acquired_cb,
+                                     name_lost_cb,
+                                     NULL, /* user_data */
+                                     NULL /* user_data_free_func */);
+
         gtk_main ();
 
        if (should_run ())
                STOP (manager);
+
         g_object_unref (manager);
+        g_bus_unown_name (name_own_id);
 
         return 0;
 }
diff --git a/plugins/common/daemon-skeleton.h b/plugins/common/daemon-skeleton.h
index 367ac1ec..23befb78 100644
--- a/plugins/common/daemon-skeleton.h
+++ b/plugins/common/daemon-skeleton.h
@@ -23,6 +23,10 @@
 #error Include PLUGIN_CFLAGS in the daemon s CFLAGS
 #endif /* !PLUGIN_NAME */
 
+#ifndef PLUGIN_DBUS_NAME
+#error Include PLUGIN_DBUS_NAME in the daemon s CFLAGS
+#endif /* !PLUGIN_DBUS_NAME */
+
 #define GNOME_SESSION_DBUS_NAME                     "org.gnome.SessionManager"
 #define GNOME_SESSION_CLIENT_PRIVATE_DBUS_INTERFACE "org.gnome.SessionManager.ClientPrivate"
 
@@ -162,12 +166,37 @@ register_with_gnome_session (GMainLoop *loop)
                           loop);
 }
 
+static void
+bus_acquired_cb (GDBusConnection *connection,
+                 const gchar *name,
+                 gpointer user_data G_GNUC_UNUSED)
+{
+        g_debug ("%s: acquired bus %p for name %s", G_STRFUNC, connection, name);
+}
+
+static void
+name_acquired_cb (GDBusConnection *connection,
+                  const gchar *name,
+                  gpointer user_data G_GNUC_UNUSED)
+{
+        g_debug ("%s: acquired name %s on bus %p", G_STRFUNC, name, connection);
+}
+
+static void
+name_lost_cb (GDBusConnection *connection,
+              const gchar *name,
+              gpointer user_data G_GNUC_UNUSED)
+{
+        g_debug ("%s: lost name %s on bus %p", G_STRFUNC, name, connection);
+}
+
 int
 main (int argc, char **argv)
 {
         GError *error = NULL;
         GOptionContext *context;
         GMainLoop *loop;
+        guint name_own_id;
 
         bindtextdomain (GETTEXT_PACKAGE, GNOME_SETTINGS_LOCALEDIR);
         bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
@@ -216,11 +245,22 @@ main (int argc, char **argv)
                }
        }
 
+       name_own_id = g_bus_own_name (G_BUS_TYPE_SESSION,
+                                     PLUGIN_DBUS_NAME,
+                                     G_BUS_NAME_OWNER_FLAGS_DO_NOT_QUEUE,
+                                     bus_acquired_cb,
+                                     name_acquired_cb,
+                                     name_lost_cb,
+                                     NULL, /* user_data */
+                                     NULL /* user_data_free_func */);
+
         g_main_loop_run (loop);
 
        if (should_run ())
                STOP (manager);
+
         g_object_unref (manager);
+        g_bus_unown_name (name_own_id);
 
         return 0;
 }
diff --git a/plugins/meson.build b/plugins/meson.build
index 3db69da7..5ff476a0 100644
--- a/plugins/meson.build
+++ b/plugins/meson.build
@@ -40,10 +40,12 @@ plugins_cflags = ['-DGNOME_SETTINGS_LOCALEDIR="@0@"'.format(gsd_localedir)]
 
 foreach plugin: [['common', '']] + enabled_plugins
   plugin_name = plugin[0]
+  plugin_dbus_name = plugin[1]
 
   cflags = [
     '-DG_LOG_DOMAIN="@0@-plugin"'.format(plugin_name),
     '-DPLUGIN_NAME="@0@"'.format(plugin_name),
+    '-DPLUGIN_DBUS_NAME="org.gnome.SettingsDaemon.@0@"'.format(plugin_dbus_name),
   ] + plugins_cflags
 
   if not ['common', 'dummy'].contains(plugin_name)