class Sprockets::Manifest

def compile(*args)
  unless environment
    raise Error, "manifest requires environment for compilation"
  end
  paths = environment.each_logical_path(*args).to_a +
    args.flatten.select { |fn| Pathname.new(fn).absolute? if fn.is_a?(String)}
  paths.each do |path|
    if asset = find_asset(path)
      files[asset.digest_path] = {
        'logical_path' => asset.logical_path,
        'mtime'        => asset.mtime.iso8601,
        'size'         => asset.bytesize,
        'digest'       => asset.digest
      }
      assets[asset.logical_path] = asset.digest_path
      target = File.join(dir, asset.digest_path)
      if File.exist?(target)
        logger.debug "Skipping #{target}, already exists"
      else
        logger.info "Writing #{target}"
        asset.write_to target
      end
      save
      asset
    end
  end
end