class Bundler::Runtime

def cache
  cache_path = "#{root}/vendor/cache/"
  FileUtils.mkdir_p(cache_path)
  Bundler.ui.info "Copying .gem files into vendor/cache"
  specs.each do |spec|
    next unless spec.source.is_a?(Source::SystemGems) || spec.source.is_a?(Source::Rubygems)
    possibilities = Gem.path.map { |p| "#{p}/cache/#{spec.full_name}.gem" }
    cached_path = possibilities.find { |p| File.exist? p }
    raise GemNotFound, "Missing gem file '#{spec.full_name}.gem'." unless cached_path
    Bundler.ui.info "  * #{File.basename(cached_path)}"
    next if File.expand_path(File.dirname(cached_path)) == File.expand_path(cache_path)
    FileUtils.cp(cached_path, cache_path)
  end
end