class Gem::Commands::RebuildCommand

def prep_dirs
  rebuild_dir = Dir.mktmpdir("gem_rebuild")
  old_dir = File.join(rebuild_dir, "old")
  new_dir = File.join(rebuild_dir, "new")
  FileUtils.mkdir_p(old_dir)
  FileUtils.mkdir_p(new_dir)
  [old_dir, new_dir]
end