gemdirs

# File lib/rdoc/ri/paths.rb, line 83
  def self.gemdirs filter = :latest
    require 'rubygems' unless defined?(Gem)

    ri_paths = {}

    all = Gem::Specification.map do |spec|
      [File.join(spec.doc_dir, 'ri'), spec.name, spec.version]
    end

    if filter == :all then
      gemdirs = []

      all.group_by do |_, name, _|
        name
      end.sort_by do |group, _|
        group
      end.map do |group, items|
        items.sort_by do |_, _, version|
          version
        end.reverse_each do |dir,|
          gemdirs << dir
        end
      end

      return gemdirs
    end

    all.each do |dir, name, ver|
      next unless File.exist? dir

      if ri_paths[name].nil? or ver > ri_paths[name].first then
        ri_paths[name] = [ver, name, dir]
      end
    end

    ri_paths.sort_by { |_, (_, name, _)| name }.map { |k, v| v.last }
  rescue LoadError
    []
  end