use crate::*;
impl<E: Engine> Audio for TransportToolbar<E> {
    fn process (&mut self, _: &Client, scope: &ProcessScope) -> Control {
        let times      = scope.cycle_times().unwrap();
        let CycleTimes { current_frames, current_usecs, next_usecs: _, period_usecs: _ } = times;
        let _chunk_size = scope.n_frames() as usize;
        let transport  = self.transport.as_ref().unwrap().query().unwrap();
        self.clock.set_sample(transport.pos.frame() as usize);
        if *self.clock.playing.read().unwrap() != Some(transport.state) {
            self.started = match transport.state {
                TransportState::Rolling => Some((current_frames as usize, current_usecs as usize)),
                TransportState::Stopped => None,
                _ => self.started
            }
        };
        *self.clock.playing.write().unwrap() = Some(transport.state);
        if *self.clock.playing.read().unwrap() == Some(TransportState::Stopped) {
            self.started = None;
        }
        match self.started {
            Some((_, usecs)) => {
                let usec = current_usecs as usize - usecs;
                let pulse = self.clock.usecs_to_pulse(usec as f64);
                self.clock.set_usec(usec);
                self.clock.set_pulse(pulse as usize);
            },
            None => { self.clock.set_usec(0); }
        };
        Control::Continue
    }
}