{
  ## main loop
  my $cache = 'current';  # Hope for the best
  if (not cache_is_good()) {
    $cache = 'stale';  # Changed expectations
    if (i_am_the_writer()) {
      if (cache_is_stale()) {
        unless (start_background_update()) {
          $cache = 'current'; # Gotta do it foreground
        }
      }
      else {
        $cache = 'current'; # Have nothing to show, gotta do it
      }
    }
    elsif(not cache_is_stale()) {
      # Stuck, gotta retry
      close_cache();
      sleep 5;
      redo;
    }

    update_cache() if $cache eq 'current'; # Make it so
  }
  show_cache($cache);
}

sub start_background_update {
  # NOTE: Uses implicit returns.
  if (i_can_fork()) {
    unless (i_am_the_parent()) {
      be_a_child();
      update_cache();
      exit 0;
    }
  }
}