Testing ruby mutexs across threads and forks

deep_thought.rb

# Deep Thought is a computer that was created by the pan-dimensional,
# hyper-intelligent species of beings (whose three-dimensional
# protrusions into our universe are ordinary white mice) to come up
# with the Answer to The Ultimate Question of Life, the Universe,
# and Everything. Deep Thought is the size of a small city.

class Worker
  MUTEX = Mutex.new
  @@mutex = Mutex.new

  def initialize name: 0, magnitude: 1
    @name = name
    @magnitude = magnitude
    @my_mutex = Mutex.new
  end

  def work
    mutex = MUTEX
    mutex = @my_mutex
    mutex = @@mutex

    while true do
      # puts "\033[33m  #{@name} is attempting to fetch lock \033[0m"
      mutex.synchronize do
        sleep_for = (rand() * @magnitude) + 1
        puts "#{Time.now.to_i} \033[35m#{@name} has mutex ##{mutex.object_id} and is sleeping for #{sleep_for}\033[0m"
        sleep sleep_for
      end
    end
  end
end

class ThreadedManager
  def initialize
    (1..2).map do |n|
      puts "booting thread #{n}"
      Thread.new do
        Worker.new(name: n, magnitude: (n+1)).work
      end
    end.map(&:join)
  end
end

class ForkedManager
  def initialize
    @color = ''
    @name = 'not-yet-forked'
    identify
    must_wait = false

    @color = "\033[33m"

    2.times do |n|
      if Process.fork
        color = "\033[35m"
        @name = 'not fork'
        identify
        must_wait = true
      else
        @name = "fork #{n}"
        identify
        must_wait = false
        Worker.new(name: @name, magnitude: (n + 1)).work
      end
    end

    if must_wait
      Process.wait
    end
  end

  def identify
    puts "#{@color} #{@name} pid: #{Process.pid} ppid: #{Process.ppid}\033[0m"
  end
end


if ARGV[0] == '--thread'
  ThreadedManager.new
end

if ARGV[0] == '--fork'
  ForkedManager.new
end

puts 'exiting'