# File referrercop, line 430
def self.load_whitelist(filename = nil)
  # Load whitelist.
  if filename == nil
    CONFIG_PATHS.each do |path|
      testname = File.join(path, 'whitelist.refcop')

      if File.exist?(testname)
        filename = testname
        break
      end
    end
  end

  $stderr.puts "Using whitelist #{filename}" if $VERBOSE && filename

  # Compile regular expressions.
  whitelist = Array.new

  unless filename == nil
    IO.foreach(filename) do |line|
      # Strip comments.
      line.strip!
      line.sub!(/#.*/, '')

      # Skip the line if it's empty.
      next if line.empty?

      # Compile the expression.
      whitelist << Regexp.new(@options.prefix + line + @options.suffix,
        Regexp::IGNORECASE)
    end

    $stderr.puts "Compiled #{whitelist.length} whitelist patterns" if $VERBOSE
  end

  return whitelist
end