Ruby pop with timeout implementation

queue_with_timeout.rb

class QueueWithTimeout
  def initialize
    @mutex = Mutex.new
    @queue = []
    @recieved = ConditionVariable.new
  end

  def <<(x)
    @mutex.synchronize do
      @queue << x
      @recieved.signal
    end
  end

  def pop(non_block = false)
    pop_with_timeout(non_block ? 0 : nil)
  end

  def  pop_with_timeout(timeout = nil)
    @mutex.synchronize do
      if @queue.empty?
        @recieved.wait(@mutex, timeout) if timeout != 0
        #if we're still empty after the timeout, raise exception
        raise ThreadError, "queue empty" if @queue.empty?
      end
      @queue.pop
    end
  end
end

Technically this is a stack with timeout (since you use @queue.pop rather than @queue.shift on L26.)