parallel-class-exec.rb

module M
  class A
    def get_value
    end
  end

  class B
    def get_value
    end
  end
end

def run(&hot_loop_block)
  if ENV["PARALLEL"]
    puts "multi-threaded"
    Thread.new(&hot_loop_block)
  elsif ENV["LOCK"]
    puts "multi-threaded (using lock)"
    @lock = Mutex.new
    Thread.new(&hot_loop_block)
  else
    puts "single-threaded"
    hot_loop_block.call
    nil
  end
end

LOOP_COUNT = 500000

def iterate(&iteration_block)
  if @lock
    LOOP_COUNT.times do
      @lock.synchronize(&iteration_block)
    end
  else
    LOOP_COUNT.times(&iteration_block)
  end
end

module N
  puts(RUBY_DESCRIPTION)

  definition_body = lambda do
    proc do
      def get_value
        nil
      end
    end.call
  end

  thread_a = run do
    iterate do
      M::A.class_exec { undef :get_value }
      M::A.class_exec(&definition_body)
      M::A.new.get_value
    end
  end

  thread_b = run do
    iterate do
      M::B.class_exec { undef :get_value }
      M::B.class_exec(&definition_body)
      M::B.new.get_value
    end
  end
  thread_a.join if thread_a
  thread_b.join if thread_b
end