module SimpleCov::ResultMerger

def synchronize_resultset
  # make it reentrant
  return yield if defined?(@resultset_locked) && @resultset_locked
  begin
    @resultset_locked = true
    File.open(resultset_writelock, "w+") do |f|
      f.flock(File::LOCK_EX)
      yield
    end
  ensure
    @resultset_locked = false
  end
end