Re: Send a message using Gio::Dbus

[Yoann LE BARS <yoann le-bars net>]

Hello everybody out there!

        No, actually, what I have done does not work.

        I have tried and make my code cleaner, including concerning messages it
send. To achieve this, I have changed the enumeration this way:

enum TypeConnexion {FREEDESKTOP, GNOME, NONE};

        Then, I have changed initialisation of the proxy to this:

proxy =
  Gio::DBus::Proxy::create_for_bus_sync(Gio::DBus::BUS_TYPE_SESSION,
                                  "org.freedesktop.PowerManagement",
                                  "org/freedesktop/PowerManagement",
                                 "org.freedesktop.PowerManagement");
if (proxy) {
  connectionType = FREEDESKTOP;
}
else {
  std::ostringstream message;
  message << "No Freedesktop type D-Bus connection available, "
          << "trying Gnome type.\n";
  g_message(message.str().c_str());

  proxy =
    Gio::DBus::Proxy::create_for_bus_sync(Gio::DBus::BUS_TYPE_SESSION,
                                          "org.gnome.SessionManager",
                                          "/org/gnome/SessionManager",
                                          "org.gnome.SessionManager");
  if (proxy) {
    connectionType = GNOME;
  }
  else {
    g_message("No D-Bus connection available.");
    connectionType = NONE;
  }
}

        Running it on Gnome 3, what I expect is failure while attempting to
connect to ["org.freedesktop.PowerManagement",
"org/freedesktop/PowerManagement", "org.freedesktop.PowerManagement"] ,
then outputting this message:

        'No Freedesktop type D-Bus connection available, trying Gnome type.'

        Then, the proxy should connect to ["org.gnome.SessionManager",
"/org/gnome/SessionManager", "org.gnome.SessionManager"] with success,
"connectionType" is set to "GNOME" and this is it.

        Here is the output I get:

(tutoriel4:8403): GLib-GIO-CRITICAL **:
g_dbus_connection_signal_subscribe: assertion `object_path == NULL ||
g_variant_is_object_path (object_path)' failed

(tutoriel4:8403): GLib-GIO-CRITICAL **:
g_dbus_connection_signal_subscribe: assertion `object_path == NULL ||
g_variant_is_object_path (object_path)' failed

(tutoriel4:8403): GLib-GIO-CRITICAL **:
g_dbus_connection_call_sync_internal: assertion `object_path != NULL &&
g_variant_is_object_path (object_path)' failed

(tutoriel4:8403): GLib-GIO-CRITICAL **:
g_dbus_connection_call_sync_internal: assertion `object_path != NULL &&
g_variant_is_object_path (object_path)' failed

        I have tried and switch into full-screen mode (which implies to inhibit
screen-saver), then back to windowed mode (which implies to uninhibit
screen-saver).

        I expected the first two messages: these are the result of attempting
to connect to an un-existing bus. But, clearly then the chosen
alternative is "if (proxy)" and connectionType is set to "FREEDESKTOP".
As a consequence, it then try and send request in Freedesktop mode,
which fails (the two last messages).

        It seems to me that "proxy" is set whether connection succeeded or not.
This is the reason previously I had to use "if (!proxy)" to obtain the
desired results, but it was an error.

        So it is all back to this question: does anyone know a way to determine
which connection is available?

        Regards.

                                                        Yoann