io multiplexing

multiplex.rb

module TermTerm
  def self.start!(command)
    master, slave = PTY.open
    comand = "script --return -c '#{command}' /dev/null"
    i,_,e,t = Open3.popen3(command, out: slave)
    multi = TermTerm::Multiplexer.new
    multi.forward($stdin, i)
    multi.forward(master, $stdout)
    multi.forward(e, $stderr)
    multi.run!
  end

  class Multiplexer
    def initialize
      @route_map = {}
    end

    def forward(from_pipe, to_pipe)
      @route_map[from_pipe] = to_pipe
    end

    def run!
      loop do
        begin
          readers, _, _ = select(@route_map.keys)
          readers.each do |reader|
            writer = @route_map[reader]
            lines = reader.read_nonblock(1000)
            writer.write lines
          end
        rescue IO::WaitReadable
          retry
        end
      end
    end
  end
end