    # File lib/rubygems/source_index.rb, line 245
      def search(gem_pattern, platform_only = false)
        version_requirement = nil
        only_platform = false

        case gem_pattern # TODO warn after 2008/03, remove three months after
        when Regexp then
          version_requirement = platform_only || Gem::Requirement.default
        when Gem::Dependency then
          only_platform = platform_only
          version_requirement = gem_pattern.version_requirements
          gem_pattern = if Regexp === gem_pattern.name then
                          gem_pattern.name
                        elsif gem_pattern.name.empty? then
                          //
                        else
                          /^#{Regexp.escape gem_pattern.name}$/
                        end
        else
          version_requirement = platform_only || Gem::Requirement.default
          gem_pattern = /#{gem_pattern}/i
        end

        unless Gem::Requirement === version_requirement then
          version_requirement = Gem::Requirement.create version_requirement
        end

        specs = @gems.values.select do |spec|
          spec.name =~ gem_pattern and
          version_requirement.satisfied_by? spec.version
        end

        if only_platform then
          specs = specs.select do |spec|
            Gem::Platform.match spec.platform
          end
        end

        specs.sort_by { |s| s.sort_obj }
      end