Method accept

3rdparty/libprocess/src/windows/poll_socket.cpp:51–139

Future<std::shared_ptr<SocketImpl>> PollSocketImpl::accept()
{
  // Need to hold a copy of `this` so that we can detect if the underlying
  // socket has changed (i.e. closed) before we return from `io::poll`.
  std::weak_ptr<SocketImpl> weak_self(shared(this));

  Try<Address> address = network::address(get());
  if (address.isError()) {
    return Failure("Failed to get address: " + address.error());
  }

  int family = 0;
  if (address->family() == Address::Family::INET4) {
    family = AF_INET;
  } else if (address->family() == Address::Family::INET6) {
    family = AF_INET6;
  } else {
    return Failure("Unsupported address family. Windows only supports IP.");
  }

  Try<int_fd> accept_socket_ = net::socket(family, SOCK_STREAM, 0);
  if (accept_socket_.isError()) {
    return Failure(accept_socket_.error());
  }

  int_fd accept_socket = accept_socket_.get();

  return windows::accept(get(), accept_socket)
    .onAny([accept_socket](const Future<Nothing> future) {
      if (!future.isReady()) {
        os::close(accept_socket);
      }
    })
    .then([weak_self, accept_socket]() -> Future<std::shared_ptr<SocketImpl>> {
      std::shared_ptr<SocketImpl> self(weak_self.lock());
      if (self == nullptr) {
        return Failure("Socket destroyed while accepting");
      }

      SOCKET listen = self->get();

      // Inherit from the listening socket.
      int res = ::setsockopt(
          accept_socket,
          SOL_SOCKET,
          SO_UPDATE_ACCEPT_CONTEXT,
          reinterpret_cast<char*>(&listen),
          sizeof(listen));

      if (res != 0) {
        const WindowsError error;
        os::close(accept_socket);
        return Failure("Failed to set accepted socket: " + error.message);
      }

      // Disable Nagle algorithm, since we care about latency more than
      // throughput. See https://en.wikipedia.org/wiki/Nagle%27s_algorithm
      // for more info.