class Middleman::SourceWatcher

def poll_once!
  updated = ::Middleman::Util.all_files_under(@directory.to_s, &method(:should_not_recurse?))
  removed = @files.keys - updated
  result = update(updated, removed)
  if @waiting_for_existence && @directory.exist?
    @waiting_for_existence = false
    listen!
  end
  result.flatten.map { |s| s[:full_path] }
end