buggered_logger_with_two_mutexes_and_a_double_check.rb

require 'thread'

class BuggeredLogger
  def initialize
    @buffer = []
    @mutex = Mutex.new
  end
  
  def maybe_flush
    flush if @buffer.size > 10
  end
  
  def flush
    return unless @buffer.size > 0
    @mutex.synchronize do
      # better check again, there's a race condition
      return unless @buffer.size > 0
      puts "*** #{@buffer.slice!(0..-1).size}"
    end
  end
  
  def log(msg)
    @mutex.synchronize do
      @buffer << msg
    end
    maybe_flush
  end
end


$logger = BuggeredLogger.new

threads = (1..50).map do |i|
  Thread.new do
    loop do
      $logger.log("HEY MAN, I AM #{i}")
      puts "logged from #{i}"
    end
  end
end

# run the hax for 60 seconds
sleep(30)