class Assassin

# File lib/assassin.rb, line 15
def Assassin.at_exit_kill(*args, &block)
  new(*args, &block)
end

# File lib/assassin.rb, line 19
def Assassin.ate(*args, &block)
  new(*args, &block)
end

# File lib/assassin.rb, line 11
def Assassin.description
  'no zombies ever, not even on `exit!` or `kill -9`'
end

# File lib/assassin.rb, line 39
def Assassin.generate(child_pid, options = {})
  path = File.join(Dir.tmpdir, "assassin-#{ child_pid }-#{ SecureRandom.uuid }.rb")
  script = Assassin.script_for(child_pid, options)
  IO.binwrite(path, script)
  pid = Process.spawn "ruby #{ path }"
  [pid, path]
end

# File lib/assassin.rb, line 28
def initialize(child_pid, options = {})
  @child_pid = child_pid.to_s.to_i
  @parent_pid = Process.pid
  @options = Assassin.options_for(options)
  @pid, @path = Assassin.generate(@child_pid, @options)
end

# File lib/assassin.rb, line 35
def Assassin.options_for(options)
  options.inject({}){|h, kv| k,v = kv; h.update(k.to_s.to_sym => v)}
end

# File lib/assassin.rb, line 47
  def Assassin.script_for(child_pid, options = {})
    parent_pid = Process.pid
    delay = (options[:delay] || 0.42).to_f

    script = <<-__
      Process.daemon

      require 'fileutils'
      at_exit{ FileUtils.rm_f(__FILE__) }

      parent_pid = #{ parent_pid }
      child_pid = #{ child_pid }
      delay = #{ delay }

      m = 24*60*60
      n = 42
      
      m.times do
        begin
          Process.kill(0, parent_pid)
        rescue Object => e
          sleep(delay)

          if e.is_a?(Errno::ESRCH)
            n.times do
              begin
                Process.kill(15, child_pid) rescue nil
                sleep(rand + rand)
                Process.kill(9, child_pid) rescue nil
                sleep(rand + rand)
                Process.kill(0, child_pid)
              rescue Errno::ESRCH
                break
              end
            end
          end

          exit
        end

        sleep(1)
      end
    __

    return script
  end

# File lib/assassin.rb, line 7
def Assassin.version
  Version
end