Method poll

source/core/StarSocket.cpp:7–107

namespace Star {

Maybe<SocketPollResult> Socket::poll(SocketPollQuery const& query, unsigned timeout) {
  if (query.empty())
    return {};

  // Prevent close from being called on any socket during this call.
  LinkedList<ReadLocker> readLockers;
  for (auto const& p : query)
    readLockers.emplaceAppend(p.first->m_mutex);

  // If any sockets are already closed, then this is an "event" according to
  // this api but we cannot call poll on a closed socket, so just poll the rest
  // of the sockets with no wait.
  SocketPollResult result;
  for (auto const& p : query) {
    if (!p.first->isOpen()) {
      result[p.first].exception = true;
      timeout = 0;
    }
  }

#ifdef STAR_SYSTEM_FAMILY_WINDOWS
  fd_set readfs;
  fd_set writefs;
  fd_set exceptfs;

  FD_ZERO(&readfs);
  FD_ZERO(&writefs);
  FD_ZERO(&exceptfs);

  int ret;
  for (auto const& p : query) {
    if (p.first->isOpen()) {
      if (p.second.readable)
        FD_SET(p.first->m_impl->socketDesc, &readfs);
      if (p.second.writable)
        FD_SET(p.first->m_impl->socketDesc, &writefs);
      FD_SET(p.first->m_impl->socketDesc, &exceptfs);
    }
  }
  timeval time;
  time.tv_usec = (timeout % 1000) * 1000;
  time.tv_sec = timeout - timeout % 1000;
  ret = ::select(0, &readfs, &writefs, &exceptfs, &time);

  if (ret < 0)
    throw NetworkException::format("Error during call to select, '{}'", netErrorString());

  if (ret == 0)
    return {};

  for (auto const& p : query) {
    if (p.first->isOpen()) {
      auto& r = result[p.first];
      r.readable = FD_ISSET(p.first->m_impl->socketDesc, &readfs);
      r.writable = FD_ISSET(p.first->m_impl->socketDesc, &writefs);
      r.exception = FD_ISSET(p.first->m_impl->socketDesc, &exceptfs);
      if (r.exception)
        p.first->doShutdown();