class Sprockets::Rails::Helpers::RailsHelper::AssetPaths

def rewrite_asset_path(source, dir, options = {})
  if source[0] == ?/
    source
  else
    source = digest_for(source) unless options[:digest] == false
    source = File.join(dir, source)
    source = "/#{source}" unless source =~ /^\//
    source
  end
end