[gnome-settings-daemon] background: convert to GDBus (and fix delayed background drawing)

[Dan Williams <dcbw src gnome org>]

commit 34d6831d7bf5fdf869f1b4802d8920c4a90825db
Author: Dan Williams <dcbw redhat com>
Date:   Wed Dec 1 11:54:17 2010 -0600

    background: convert to GDBus (and fix delayed background drawing)
    
    For some reason the signal filter with plain DBus wasn't working
    correctly, leading to no background when nautilus was for whatever
    reason not autolaunched, and show-desktop-icons was TRUE.  In any
    case it should be GDBus not libdbus, so port it.  That also
    happens to fix the signal listening issue.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=636233

 plugins/background/gsd-background-manager.c |  107 ++++++++++++++++-----------
 1 files changed, 65 insertions(+), 42 deletions(-)
---
diff --git a/plugins/background/gsd-background-manager.c b/plugins/background/gsd-background-manager.c
index 30370fa..071eb85 100644
--- a/plugins/background/gsd-background-manager.c
+++ b/plugins/background/gsd-background-manager.c
@@ -32,10 +32,9 @@
 
 #include <locale.h>
 
-#include <dbus/dbus.h>
-
 #include <glib.h>
 #include <glib/gi18n.h>
+#include <gio/gio.h>
 #include <gdk/gdk.h>
 #include <gdk/gdkx.h>
 
@@ -54,7 +53,8 @@ struct GsdBackgroundManagerPrivate
         GnomeBG     *bg;
         guint        timeout_id;
 
-        DBusConnection *dbus_connection;
+        GDBusProxy  *proxy;
+        guint        proxy_signal_id;
 };
 
 static void     gsd_background_manager_class_init  (GsdBackgroundManagerClass *klass);
@@ -287,53 +287,77 @@ queue_draw_background (GsdBackgroundManager *manager)
         return FALSE;
 }
 
-static DBusHandlerResult
-on_bus_message (DBusConnection *connection,
-                DBusMessage    *message,
-                void           *user_data)
+static void
+queue_timeout (GsdBackgroundManager *manager)
 {
-        GsdBackgroundManager *manager = user_data;
-
-        if (dbus_message_is_signal (message,
-                                    "org.gnome.SessionManager",
-                                    "SessionRunning")) {
-                /* If the session finishes then check if nautilus is
-                 * running and if not, set the background.
-                 *
-                 * We wait a few seconds after the session is up
-                 * because nautilus tells the session manager that its
-                 * ready before it sets the background.
-                 */
-                manager->priv->timeout_id = g_timeout_add_seconds (8,
-                                                                   (GSourceFunc)
-                                                                   queue_draw_background,
-                                                                   manager);
-                dbus_connection_remove_filter (connection,
-                                               on_bus_message,
-                                               manager);
-
-                manager->priv->dbus_connection = NULL;
-        }
+        if (manager->priv->timeout_id > 0)
+                return;
 
-        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+        /* If the session finishes then check if nautilus is
+         * running and if not, set the background.
+         *
+         * We wait a few seconds after the session is up
+         * because nautilus tells the session manager that its
+         * ready before it sets the background.
+         */
+        manager->priv->timeout_id = g_timeout_add_seconds (8,
+                                                           (GSourceFunc)
+                                                           queue_draw_background,
+                                                           manager);
 }
 
 static void
-draw_background_after_session_loads (GsdBackgroundManager *manager)
+disconnect_session_manager_listener (GsdBackgroundManager *manager)
 {
-        DBusConnection *connection;
+        if (manager->priv->proxy && manager->priv->proxy_signal_id) {
+                g_signal_handler_disconnect (manager->priv->proxy,
+                                             manager->priv->proxy_signal_id);
+                manager->priv->proxy_signal_id = 0;
+        }
+}
 
-        connection = dbus_bus_get (DBUS_BUS_SESSION, NULL);
+static void
+on_session_manager_signal (GDBusProxy   *proxy,
+                           const gchar  *sender_name,
+                           const gchar  *signal_name,
+                           GVariant     *parameters,
+                           gpointer      user_data)
+{
+        GsdBackgroundManager *manager = GSD_BACKGROUND_MANAGER (user_data);
 
-        if (connection == NULL) {
-                return;
+        if (g_strcmp0 (signal_name, "SessionRunning") == 0) {
+                queue_timeout (manager);
+                disconnect_session_manager_listener (manager);
         }
+}
 
-        if (!dbus_connection_add_filter (connection, on_bus_message, manager, NULL)) {
+static void
+draw_background_after_session_loads (GsdBackgroundManager *manager)
+{
+        GError *error = NULL;
+        GDBusProxyFlags flags;
+
+        flags = G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES |
+                G_DBUS_PROXY_FLAGS_DO_NOT_AUTO_START;
+        manager->priv->proxy = g_dbus_proxy_new_for_bus_sync (G_BUS_TYPE_SESSION,
+                                                              flags,
+                                                              NULL, /* GDBusInterfaceInfo */
+                                                              "org.gnome.SessionManager",
+                                                              "/org/gnome/SessionManager",
+                                                              "org.gnome.SessionManager",
+                                                              NULL, /* GCancellable */
+                                                              &error);
+        if (manager->priv->proxy == NULL) {
+                g_warning ("Could not listen to session manager: %s",
+                           error->message);
+                g_error_free (error);
                 return;
-        };
+        }
 
-        manager->priv->dbus_connection = connection;
+        manager->priv->proxy_signal_id = g_signal_connect (manager->priv->proxy,
+                                                           "g-signal",
+                                                           G_CALLBACK (on_session_manager_signal),
+                                                           manager);
 }
 
 
@@ -423,10 +447,9 @@ gsd_background_manager_stop (GsdBackgroundManager *manager)
 
         disconnect_screen_signals (manager);
 
-        if (manager->priv->dbus_connection != NULL) {
-                dbus_connection_remove_filter (manager->priv->dbus_connection,
-                                               on_bus_message,
-                                               manager);
+        if (manager->priv->proxy) {
+                disconnect_session_manager_listener (manager);
+                g_object_unref (manager->priv->proxy);
         }
 
         g_signal_handlers_disconnect_by_func (manager->priv->settings,