cache_dir

# File lib/rubygems/source.rb, line 115
  def cache_dir(uri)
    # Correct for windows paths
    escaped_path = uri.path.sub(/^\/([a-z]):\//, '/\1-/')
    escaped_path.untaint

    File.join Gem.spec_cache_dir, "#{uri.host}%#{uri.port}", File.dirname(escaped_path)
  end