gnome-shell/js/misc/screenSaver.js

// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-

const Gio = imports.gi.Gio;
const Lang = imports.lang;

const ScreenSaverIface = <interface name="org.gnome.ScreenSaver">
<method name="GetActive">
    <arg type="b" direction="out" />
</method>
<method name="Lock" />
<method name="SetActive">
    <arg type="b" direction="in" />
</method>
<signal name="ActiveChanged">
    <arg type="b" direction="out" />
</signal>
</interface>;

const ScreenSaverInfo = Gio.DBusInterfaceInfo.new_for_xml(ScreenSaverIface);

function ScreenSaverProxy() {
    var self = new Gio.DBusProxy({ g_connection: Gio.DBus.session,
				   g_interface_name: ScreenSaverInfo.name,
				   g_interface_info: ScreenSaverInfo,
				   g_name: 'org.gnome.ScreenSaver',
				   g_object_path: '/org/gnome/ScreenSaver',
                                   g_flags: (Gio.DBusProxyFlags.DO_NOT_AUTO_START |
                                             Gio.DBusProxyFlags.DO_NOT_LOAD_PROPERTIES) });
    self.init(null);
    self.screenSaverActive = false;

    self.connectSignal('ActiveChanged', function(proxy, senderName, [isActive]) {
        self.screenSaverActive = isActive;
    });
    self.connect('notify::g-name-owner', function() {
        if (self.g_name_owner) {
            self.GetActiveRemote(function(result, excp) {
                if (result) {
                    let [isActive] = result;
                    self.screenSaverActive = isActive;
                }
            });
        } else
            self.screenSaverActive = false;
    });

    return self;
}