from_io (Gem::Format)

    # File lib/rubygems/format.rb, line 64
      def self.from_io(io, gem_path="(io)", security_policy = nil)
        format = new gem_path

        Gem::Package.open io, 'r', security_policy do |pkg|
          format.spec = pkg.metadata
          format.file_entries = []

          pkg.each do |entry|
            size = entry.header.size
            mode = entry.header.mode

            format.file_entries << [{
                "size" => size, "mode" => mode, "path" => entry.full_name,
              },
              entry.read
            ]
          end
        end

        format
      end