fn capture_error()

in neqo-transport/src/connection/mod.rs [914:969]
52 lines of code
7 McCabe index (conditional complexity)

    fn capture_error<T>(
        &mut self,
        path: Option<PathRef>,
        now: Instant,
        frame_type: FrameType,
        res: Res<T>,
    ) -> Res<T> {
        if let Err(v) = &res {
            #[cfg(debug_assertions)]
            let msg = format!("{v:?}");
            #[cfg(not(debug_assertions))]
            let msg = "";
            let error = CloseReason::Transport(v.clone());
            match &self.state {
                State::Closing { error: err, .. }
                | State::Draining { error: err, .. }
                | State::Closed(err) => {
                    qwarn!("[{self}] Closing again after error {err:?}");
                }
                State::Init => {
                    // We have not even sent anything just close the connection without sending any
                    // error. This may happen when client_start fails.
                    self.set_state(State::Closed(error), now);
                }
                State::WaitInitial | State::WaitVersion => {
                    // We don't have any state yet, so don't bother with
                    // the closing state, just send one CONNECTION_CLOSE.
                    if let Some(path) = path.or_else(|| self.paths.primary()) {
                        self.state_signaling
                            .close(path, error.clone(), frame_type, msg);
                    }
                    self.set_state(State::Closed(error), now);
                }
                _ => {
                    if let Some(path) = path.or_else(|| self.paths.primary()) {
                        self.state_signaling
                            .close(path, error.clone(), frame_type, msg);
                        if matches!(v, Error::KeysExhausted) {
                            self.set_state(State::Closed(error), now);
                        } else {
                            self.set_state(
                                State::Closing {
                                    error,
                                    timeout: self.get_closing_period_time(now),
                                },
                                now,
                            );
                        }
                    } else {
                        self.set_state(State::Closed(error), now);
                    }
                }
            }
        }
        res
    }