Pure Ruby Queue sample

prqueue.rb

#! /usr/bin/env ruby

class PureRubyQueue
  def initialize
    @que = []
    @waiters = []
  end

  def push(obj)
    @que << obj
    while t = @waiters.shift
      if t.wakeup
        break
      end
    end
    self
  end

  def pop(non_block=false)
    while @que.length == 0
      if non_block
        raise ThreadError, "queue empty"
      end

      @waiters << Thread.current
      begin
        Thread.stop
      ensure
        @waiters.delete(Thread.current)
      end
    end
    @que.shift
  end
end

[Queue, PureRubyQueue].each do |klass|
  q = klass.new
  10.times do |i|
    q.push i
  end

  threads = []
  3.times do
    threads << Thread.new {
      begin
        while val = q.pop(true)
          p val
          sleep 0.1
        end
      rescue ThreadError
        puts "thread finish!"
      end
    }
  end
  threads.each(&:join)
  puts "thread all joined"
end