fn accept()

in src/core/server/src/listener.rs [115:158]
38 lines of code
9 McCabe index (conditional complexity)

    fn accept(&mut self) {
        for _ in 0..ACCEPT_BATCH {
            if let Ok(mut session) = self.listener.accept().map(Session::from) {
                if session.is_handshaking() {
                    let s = self.sessions.vacant_entry();
                    let interest = session.interest();
                    if session
                        .register(self.poll.registry(), Token(s.key()), interest)
                        .is_ok()
                    {
                        s.insert(session);
                    } else {
                        // failed to register
                    }
                } else {
                    for attempt in 1..=QUEUE_RETRIES {
                        if let Err(s) = self.session_queue.try_send_any(session) {
                            if attempt == QUEUE_RETRIES {
                                LISTENER_SESSION_DISCARD.increment();
                            } else {
                                let _ = self.session_queue.wake();
                            }
                            session = s;
                        } else {
                            break;
                        }
                    }
                    // if pushing to the session queues fails, the session will be
                    // closed on drop here
                }
            } else {
                return;
            }
        }

        // reregister is needed here so we will call accept if there is a backlog
        if self
            .listener
            .reregister(self.poll.registry(), LISTENER_TOKEN, Interest::READABLE)
            .is_err()
        {
            // failed to reregister listener? how do we handle this?
        }
    }