Re: Send a message using Gio::Dbus

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

Hello everybody out there!

On 03/07/2013 8:41 p.m., Andrew Potter wrote:
> Try Glib::RefPtr<Gio::DBus::Proxy> proxy
> = Gio::DBus::Proxy::create_for_bus_sync(Gio::DBus::BUS_TYPE_SESSION,
>                                         "org.gnome.ScreenSaver",
>                                         "/org/gnome/ScreenSaver",
>                                         "org.gnome.ScreenSaver");

Thank you, it was of some help.

        But…

        I have taken a look to VLC code, especially on inhibiting code. It
appears that to not getting any trouble, I would rather connect to
["org.gnome.SessionManager", "org/gnome/SessionManager",
"org.gnome.SessionManager"], which leads to this:

Glib::RefPtr<Gio::DBus::Proxy> proxy
  = Gio::DBus::Proxy::create_for_bus_sync(Gio::DBus::BUS_TYPE_SESSION,
                                          "org.gnome.SessionManager",
                                          "/org/gnome/SessionManager",
                                          "org.gnome.SessionManager");

Then, I have found GNOME Session documentation
(<http://people.gnome.org/~mccann/gnome-session/docs/gnome-session.html>).
The part concerning the "Inhibit" method
(<http://people.gnome.org/~mccann/gnome-session/docs/gnome-session.html#org.gnome.SessionManager.Inhibit>)
indicates it takes more arguments than I thought, which are:

                - application ID;
                - Top-level XId;
                - the reason for inhibition;
                - flags, for what I ask it should be set such as: 4 | 8.

        This leads to the following:

void Interface::Fenetre::inhibitScreenSaver() {
  /* Application Id. */
  Glib::Variant<Glib::ustring> app_name =
    Glib::Variant<Glib::ustring>::create("Tutorial4");
  /* Window XId. */
  Glib::Variant<guint> toplevel_xid =
    Glib::Variant<guint>::create(GDK_WINDOW_XID(get_window()->gobj()));
  /* Reason for inhibition. */
  Glib::Variant<Glib::ustring> reason =
    Glib::Variant<Glib::ustring>::create("Full-screen animation");
  /* Flags. */
  Glib::Variant<guint> flag =
    Glib::Variant<guint>::create(4 | 8);
  /* Vector containing the message. */
  std::vector<Glib::VariantBase> vec;
  vec.push_back(app_name);
  vec.push_back(toplevel_xid);
  vec.push_back(reason);
  vec.push_back(flag);
  /* Bundling the message. */
  Glib::VariantContainerBase bundle =
    Glib::VariantContainerBase::create_tuple(vec);
  result = proxy->call_sync("Inhibit", bundle);
}

Uninhibiting part of the manual
(<http://people.gnome.org/~mccann/gnome-session/docs/gnome-session.html#org.gnome.SessionManager.Uninhibit>)
does not show anything special, which leads to this code:

void Interface::Fenetre::uninhibitScreenSaver() {
  proxy->call_sync("Uninhibit", result);
}

I have tried and test it, it works as expected: I have waited for some
time in full-screen mode, the screen never turned black. When switching
back to windowed mode, after a while, the screen turned black. No error
message appeared. This is good!

        I guess I am starting to get it and to understand D-Bus messages.

        But…

        I want my application to be usable on any D-Bus using system.

        Looking into VLC, on environments using specifications from
Freedesktop.org (such as KDE or Gnome <= 2.26), I should connect to
["org.freedesktop.PowerManagement", "org/freedesktop/PowerManagement",
"org.freedesktop.PowerManagement"], and use method "Inhibit" with the
following arguments:

                - application ID ;

                - reason for suspending.

        To un-inhibit, the method is call "UnInhibit" and as argument simply
take the cookie obtained when inhibiting.

        So, what I need is to determined which bus is available. Unfortunately,
I did not find out how it is done in VLC. Does someone know how to get
available buses?

        Regards.

                                                        Yoann