std::tuple lookupAddrForHostname()

in tensorpipe/transport/ibv/utility.cc [128:174]

• 37 lines of code
• 9 McCabe index (conditional complexity)

std::tuple<Error, std::string> lookupAddrForHostname() {
  Error error;
  std::string hostname;
  std::tie(error, hostname) = getHostname();
  if (error) {
    return std::make_tuple(std::move(error), std::string());
  }

  AddressInfo info;
  std::tie(error, info) = createAddressInfo(std::move(hostname));
  if (error) {
    return std::make_tuple(std::move(error), std::string());
  }

  Error firstError;
  for (struct addrinfo* rp = info.get(); rp != nullptr; rp = rp->ai_next) {
    TP_DCHECK(rp->ai_family == AF_INET || rp->ai_family == AF_INET6);
    TP_DCHECK_EQ(rp->ai_socktype, SOCK_STREAM);
    TP_DCHECK_EQ(rp->ai_protocol, IPPROTO_TCP);

    Sockaddr addr = Sockaddr(rp->ai_addr, rp->ai_addrlen);

    Socket socket;
    std::tie(error, socket) = Socket::createForFamily(rp->ai_family);

    if (!error) {
      error = socket.bind(addr);
    }

    if (error) {
      // Record the first binding error we encounter and return that in the end
      // if no working address is found, in order to help with debugging.
      if (!firstError) {
        firstError = error;
      }
      continue;
    }

    return std::make_tuple(Error::kSuccess, addr.str());
  }

  if (firstError) {
    return std::make_tuple(std::move(firstError), std::string());
  } else {
    return std::make_tuple(TP_CREATE_ERROR(NoAddrFoundError), std::string());
  }
}