class Gem::Commands::UnpackCommand

def execute
  security_policy = options[:security_policy]
  get_all_gem_names.each do |name|
    dependency = Gem::Dependency.new name, options[:version]
    path = get_path dependency
    unless path
      alert_error "Gem '#{name}' not installed nor fetchable."
      next
    end
    if @options[:spec]
      spec, metadata = Gem::Package.raw_spec(path, security_policy)
      if metadata.nil?
        alert_error "--spec is unsupported on '#{name}' (old format gem)"
        next
      end
      spec_file = File.basename spec.spec_file
      FileUtils.mkdir_p @options[:target] if @options[:target]
      destination = begin
        if @options[:target]
          File.join @options[:target], spec_file
        else
          spec_file
        end
      end
      File.open destination, 'w' do |io|
        io.write metadata
      end
    else
      basename = File.basename path, '.gem'
      target_dir = File.expand_path basename, options[:target]
      package = Gem::Package.new path, security_policy
      package.extract_files target_dir
      say "Unpacked gem: '#{target_dir}'"
    end
  end
end