# File lib/rdoc/ri/store.rb, line 260
  def save_class klass
    full_name = klass.full_name

    FileUtils.mkdir_p class_path(full_name) unless @dry_run

    @cache[:modules] << full_name

    path = class_file full_name

    begin
      disk_klass = load_class full_name

      klass = disk_klass.merge klass
    rescue Errno::ENOENT
    end

    # BasicObject has no ancestors
    ancestors = klass.ancestors.compact.map do |ancestor|
      # HACK for classes we don't know about (class X < RuntimeError)
      String === ancestor ? ancestor : ancestor.full_name
    end

    @cache[:ancestors][full_name] ||= []
    @cache[:ancestors][full_name].push(*ancestors)

    attributes = klass.attributes.map do |attribute|
      "#{attribute.definition} #{attribute.name}"
    end

    unless attributes.empty? then
      @cache[:attributes][full_name] ||= []
      @cache[:attributes][full_name].push(*attributes)
    end

    to_delete = []

    unless klass.method_list.empty? then
      @cache[:class_methods][full_name]    ||= []
      @cache[:instance_methods][full_name] ||= []

      class_methods, instance_methods =
        klass.method_list.partition { |meth| meth.singleton }

      class_methods    = class_methods.   map { |method| method.name }
      instance_methods = instance_methods.map { |method| method.name }

      old = @cache[:class_methods][full_name] - class_methods
      to_delete.concat old.map { |method|
        method_file full_name, "#{full_name}::#{method}"
      }

      old = @cache[:instance_methods][full_name] - instance_methods
      to_delete.concat old.map { |method|
        method_file full_name, "#{full_name}##{method}"
      }

      @cache[:class_methods][full_name]    = class_methods
      @cache[:instance_methods][full_name] = instance_methods
    end

    return if @dry_run

    FileUtils.rm_f to_delete

    marshal = Marshal.dump klass

    open path, 'wb' do |io|
      io.write marshal
    end
  end