Created attachment 182111 [details] [review]
D-Bus: Support ObjectPath called parameter in GDBus servers

When adding a method to a DBus Object (server) that includes one parameter of
type GLib.ObjectPath with the DBus attribute "called_object_path = true", then
it's used for referencing the called object path.

This allows to create just one DBus object (or just one kind), and register it
for multiple paths, then you can perform multiple actions for each called path
in methods.

While this is not so needed with register_object, this is a must for implementing
the register_subtree GDBus feature.

The patch includes also a check for dbus client: if a called object path is used, then it's not considered when connecting to the dbus method itself.

===================================================================
Here's an example working with it:

[DBus (name = "org.example.BasicDemo")]
public class DemoServer : Object {

    private int counter;

    public int ping (string msg, GLib.BusName sender,
                     [DBus (called_object_path = true)] GLib.ObjectPath path) {
        stdout.printf ("%s - %s - %s\n", msg, sender, path);

        switch (Path.get_basename(path)) {
            case "demo":
                print("Using the demo path obj\n");
                break;
            case "subpath":
                print("Using the subpath subpath obj\n");
                break;
        }
        return counter++;
    }

	public int ping_obj_path (string msg, GLib.BusName sender, GLib.ObjectPath path) {
        stdout.printf ("%s - %s - %s\n", msg, sender, path);
        return counter++;
    }
}

void on_bus_aquired (DBusConnection conn) {
    try {
        var server = new DemoServer ();
        conn.register_object ("/org/basic/example/demo", server);
        conn.register_object ("/org/basic/example/demo/subpath", server);
    } catch (IOError e) {
        stderr.printf ("Could not register service\n");
    }
}

void main () {
    Bus.own_name (BusType.SESSION, "org.Basic.Example.Demo", BusNameOwnerFlags.NONE,
                  on_bus_aquired,
                  () => {},
                  () => stderr.printf ("Could not aquire name\n"));

    new MainLoop ().run ();
}