Generate “open” signal for g_application about gio HOT 7 CLOSED

impl<O: IsA<Application> + IsA<glib::object::Object>> ApplicationExtManual for O {
   fn connect_open<F: Fn(&Self, &[File], &str) + 'static>(&self, f: F) -> u64 {
        unsafe {
            let f: Box_<Box_<Fn(&Self, &[File], &str) + 'static>> = Box_::new(Box_::new(f));
            connect(self.to_glib_none().0, "open",
                transmute(open_trampoline::<Self> as usize), Box_::into_raw(f) as *mut _)
        }
    }
}
unsafe extern "C" fn open_trampoline<P>(this: *mut ffi::GApplication, files: *const *mut ffi::GFile, n_files: libc::c_int, hint: *mut libc::c_char, f: glib_ffi::gpointer)
where P: IsA<Application> {
    callback_guard!();
    let f: &Box_<Fn(&P, &[File], &str) + 'static> = transmute(f);
    let files: Vec<File> = FromGlibPtrContainer::from_glib_none_num(files, n_files as usize);
    f(&Application::from_glib_none(this).downcast_unchecked(), &files[..], &String::from_glib_none(hint))
}