asio::error_code signal_set_service::remove()

in demo_example/asio/asio/detail/impl/signal_set_service.ipp [382:450]

• 56 lines of code
• 16 McCabe index (conditional complexity)

asio::error_code signal_set_service::remove(
    signal_set_service::implementation_type& impl,
    int signal_number, asio::error_code& ec)
{
  // Check that the signal number is valid.
  if (signal_number < 0 || signal_number >= max_signal_number)
  {
    ec = asio::error::invalid_argument;
    return ec;
  }

  signal_state* state = get_signal_state();
  static_mutex::scoped_lock lock(state->mutex_);

  // Find the signal number in the list of registrations.
  registration** deletion_point = &impl.signals_;
  registration* reg = impl.signals_;
  while (reg && reg->signal_number_ < signal_number)
  {
    deletion_point = &reg->next_in_set_;
    reg = reg->next_in_set_;
  }

  if (reg != 0 && reg->signal_number_ == signal_number)
  {
#if defined(ASIO_HAS_SIGNAL) || defined(ASIO_HAS_SIGACTION)
    // Set signal handler back to the default if we're the last.
    if (state->registration_count_[signal_number] == 1)
    {
# if defined(ASIO_HAS_SIGACTION)
      using namespace std; // For memset.
      struct sigaction sa;
      memset(&sa, 0, sizeof(sa));
      sa.sa_handler = SIG_DFL;
      if (::sigaction(signal_number, &sa, 0) == -1)
# else // defined(ASIO_HAS_SIGACTION)
      if (::signal(signal_number, SIG_DFL) == SIG_ERR)
# endif // defined(ASIO_HAS_SIGACTION)
      {
# if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
        ec = asio::error::invalid_argument;
# else // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
        ec = asio::error_code(errno,
            asio::error::get_system_category());
# endif // defined(ASIO_WINDOWS) || defined(__CYGWIN__)
        return ec;
      }
    }
#endif // defined(ASIO_HAS_SIGNAL) || defined(ASIO_HAS_SIGACTION)

    // Remove the registration from the set.
    *deletion_point = reg->next_in_set_;

    // Remove the registration from the registration table.
    if (registrations_[signal_number] == reg)
      registrations_[signal_number] = reg->next_in_table_;
    if (reg->prev_in_table_)
      reg->prev_in_table_->next_in_table_ = reg->next_in_table_;
    if (reg->next_in_table_)
      reg->next_in_table_->prev_in_table_ = reg->prev_in_table_;

    --state->registration_count_[signal_number];

    delete reg;
  }

  ec = asio::error_code();
  return ec;
}