From 5863f7907e3dab17e09b4e8d30eb751cb638ae19 Mon Sep 17 00:00:00 2001
From: "Mario J. Rugiero" <mrugiero@gmail.com>
Date: Fri, 5 Jul 2019 05:20:59 -0300
Subject: [PATCH] Take ownership of the well-known D-Bus name synchronously.

---
 src/appfinder-gdbus.c | 82 ++++++++++++++++++++++++++++---------------
 1 file changed, 53 insertions(+), 29 deletions(-)

diff --git a/src/appfinder-gdbus.c b/src/appfinder-gdbus.c
index 4ab342d..b49d774 100644
--- a/src/appfinder-gdbus.c
+++ b/src/appfinder-gdbus.c
@@ -104,15 +104,55 @@ static const GDBusInterfaceVTable appfinder_gdbus_vtable =
 
 
 
-static void
-appfinder_gdbus_bus_acquired (GDBusConnection *connection,
-                              const gchar     *name,
-                              gpointer         user_data)
+gboolean
+appfinder_gdbus_service (GError **error)
 {
-  guint          register_id;
-  GDBusNodeInfo *info;
-  GError        *error = NULL;
+  GDBusConnection   *connection;
+  guint32            request_name_reply;
+  GVariant          *params = g_variant_new ("(su)",
+                                             APPFINDER_DBUS_SERVICE,
+                                             G_BUS_NAME_OWNER_FLAGS_DO_NOT_QUEUE);
+  GVariant          *result;
+  guint              register_id;
+  GDBusNodeInfo     *info;
+
+  connection = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, error);
+  if (G_UNLIKELY (connection == NULL))
+    return FALSE;
+
+  /* The g_bus_* API doesn't provide the means for synchronously owning a name. */
+  result = g_dbus_connection_call_sync (connection,
+                                        "org.freedesktop.DBus",
+                                        "/org/freedesktop/DBus",
+                                        "org.freedesktop.DBus",
+                                        "RequestName",
+                                        params,
+                                        NULL,
+                                        G_DBUS_CALL_FLAGS_NONE,
+                                        -1,
+                                        NULL,
+                                        error);
+
+  if (!result)
+    {
+      g_message ("Failed to request name: %s", (*error)->message);
+      g_error_free (*error);
+      g_object_unref (connection);
+      return FALSE;
+    }
+
+  g_variant_get (result, "(u)", &request_name_reply);
+  g_variant_unref (result);
 
+  /* There's already another server up. */
+  /* 1 == DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER, i.e. we got it. */
+  if (request_name_reply != 1)
+    {
+      g_object_unref (connection);
+      return FALSE;
+    }
+
+  /* We're the server, let's start serving! */
   info = g_dbus_node_info_new_for_xml (appfinder_gdbus_introspection_xml, NULL);
   g_assert (info != NULL);
   g_assert (*info->interfaces != NULL);
@@ -121,38 +161,22 @@ appfinder_gdbus_bus_acquired (GDBusConnection *connection,
                                                    APPFINDER_DBUS_PATH,
                                                    *info->interfaces, /* first iface */
                                                    &appfinder_gdbus_vtable,
-                                                   user_data,
                                                    NULL,
-                                                   &error);
+                                                   NULL,
+                                                   error);
 
   APPFINDER_DEBUG ("registered interface with id %d", register_id);
 
   if (register_id == 0)
     {
-      g_message ("Failed to register object: %s", error->message);
-      g_error_free (error);
+      g_message ("Failed to register object: %s", (*error)->message);
+      g_error_free (*error);
     }
 
   g_dbus_node_info_unref (info);
-}
 
-
-
-gboolean
-appfinder_gdbus_service (GError **error)
-{
-  guint owner_id;
-
-  owner_id = g_bus_own_name (G_BUS_TYPE_SESSION,
-                             APPFINDER_DBUS_SERVICE,
-                             G_BUS_NAME_OWNER_FLAGS_NONE,
-                             appfinder_gdbus_bus_acquired,
-                             NULL,
-                             NULL,
-                             NULL,
-                             NULL);
-
-  return (owner_id != 0);
+  /* N.B.: leaks the connection on purpose. */
+  return TRUE;
 }
 
 
-- 
2.20.1