class Bundler::Source::Rubygems

def fetch_gem(spec)
  return false unless spec.remote
  uri = spec.remote.uri
  spec.fetch_platform
  download_path = Bundler.requires_sudo? ? Bundler.tmp(spec.full_name) : Bundler.rubygems.gem_dir
  gem_path = "#{Bundler.rubygems.gem_dir}/cache/#{spec.full_name}.gem"
  SharedHelpers.filesystem_access("#{download_path}/cache") do |p|
    FileUtils.mkdir_p(p)
  end
  Bundler.rubygems.download_gem(spec, uri, download_path)
  if Bundler.requires_sudo?
    SharedHelpers.filesystem_access("#{Bundler.rubygems.gem_dir}/cache") do |p|
      Bundler.mkdir_p(p)
    end
    Bundler.sudo "mv #{download_path}/cache/#{spec.full_name}.gem #{gem_path}"
  end
  gem_path
ensure
  Bundler.rm_rf(download_path) if Bundler.requires_sudo?
end