handle vendor/gems in rails 2.2 as a dir for gems, not foreign alien shit that it is today

rails_vendor_gems_ng.rb

# see mail reply in http://groups.google.com/group/haml/msg/12f63d9dff34a1d5
# with explanation about how/why this works better than rails 2.2

module Rails
  class VendorGemSourceIndex

    def gemspec_filename(d)
      File.join(d,"#{File.basename(d)}.gemspec")
    end

    def load_specification(d)
      Dir.chdir(d) { return eval(File.read(gemspec_filename(d))) }
    end

    def refresh!
      # reload the installed gems
      @installed_source_index.refresh!
      vendor_gems = {}

      # handle vendor Rails gems - they are identified by having loaded_from set to ""
      # we add them manually to the list, so that other gems can find them via dependencies
      Gem.loaded_specs.each do |n, s|
        next unless s.loaded_from.empty?
        vendor_gems[s.full_name] = s
      end

      # load specifications from vendor/gems
      Dir[File.join(Rails::GemDependency.unpacked_path, '*')].each do |d|
        spec = load_specification(d)
        spec.loaded_from = gemspec_filename(d)
        # finally, swap out full_gem_path
        class << spec
          def full_gem_path=(path)
            @full_gem_path = path
          end
          def full_gem_path
            @full_gem_path
          end
        end
        spec.full_gem_path = d
        vendor_gems[File.basename(d)] = spec
      end
      @vendor_source_index = Gem::SourceIndex.new(vendor_gems)
    end

  end
end