void Worker::newTCPConnection()

in src/server/worker.cc [114:194]
74 lines of code
12 McCabe index (conditional complexity)

void Worker::newTCPConnection(evconnlistener *listener, evutil_socket_t fd, [[maybe_unused]] sockaddr *address,
                              [[maybe_unused]] int socklen) {
  int local_port = util::GetLocalPort(fd);  // NOLINT
  debug("[worker] New connection: fd={} from port: {} thread #{}", fd, local_port, fmt::streamed(tid_));

  auto s = util::SockSetTcpKeepalive(fd, 120);
  if (!s.IsOK()) {
    error("[worker] Failed to set tcp-keepalive on socket. Error: {}", s.Msg());
    evutil_closesocket(fd);
    return;
  }

  s = util::SockSetTcpNoDelay(fd, 1);
  if (!s.IsOK()) {
    error("[worker] Failed to set tcp-nodelay on socket. Error: {}", s.Msg());
    evutil_closesocket(fd);
    return;
  }

  event_base *base = evconnlistener_get_base(listener);
  auto ev_thread_safe_flags =
      BEV_OPT_THREADSAFE | BEV_OPT_DEFER_CALLBACKS | BEV_OPT_UNLOCK_CALLBACKS | BEV_OPT_CLOSE_ON_FREE;

  bufferevent *bev = nullptr;
  ssl_st *ssl = nullptr;
#ifdef ENABLE_OPENSSL
  if (uint32_t(local_port) == srv->GetConfig()->tls_port) {
    ssl = SSL_new(srv->ssl_ctx.get());
    if (!ssl) {
      error("[worker] Failed to construct SSL structure for new connection: {}", fmt::streamed(SSLErrors{}));
      evutil_closesocket(fd);
      return;
    }
    bev = bufferevent_openssl_socket_new(base, fd, ssl, BUFFEREVENT_SSL_ACCEPTING, ev_thread_safe_flags);
  } else {
    bev = bufferevent_socket_new(base, fd, ev_thread_safe_flags);
  }
#else
  bev = bufferevent_socket_new(base, fd, ev_thread_safe_flags);
#endif
  if (!bev) {
    auto socket_err = evutil_socket_error_to_string(EVUTIL_SOCKET_ERROR());
#ifdef ENABLE_OPENSSL
    error("[worker] Failed to construct socket for new connection: {}, SSL error: {}", socket_err,
          fmt::streamed(SSLErrors{}));
    if (ssl) SSL_free(ssl);
#else
    error("[worker] Failed to construct socket for new connection: {}", socket_err);
#endif
    evutil_closesocket(fd);
    return;
  }
#ifdef ENABLE_OPENSSL
  if (uint32_t(local_port) == srv->GetConfig()->tls_port) {
    bufferevent_openssl_set_allow_dirty_shutdown(bev, 1);
  }
#endif
  auto conn = new redis::Connection(bev, this);
  conn->SetCB(bev);
  bufferevent_enable(bev, EV_READ);

  s = AddConnection(conn);
  if (!s.IsOK()) {
    std::string err_msg = redis::Error({Status::NotOK, s.Msg()});
    s = util::SockSend(fd, err_msg, ssl);
    if (!s.IsOK()) {
      warn("[worker] Failed to send error response to socket: {}", s.Msg());
    }
    conn->Close();
    return;
  }

  if (auto s = util::GetPeerAddr(fd)) {
    auto [ip, port] = std::move(*s);
    conn->SetAddr(ip, port);
  }

  if (rate_limit_group_) {
    bufferevent_add_to_rate_limit_group(bev, rate_limit_group_);
  }
}