Module: ThreadingTestTools

Defined in:
lib/threading_test_tools.rb

Defined Under Namespace

Classes: RaceConditionFound

Instance Method Summary collapse

Instance Method Details

#analyze_race_condition_test(data) ⇒ Object 



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# File 'lib/threading_test_tools.rb', line 134

def analyze_race_condition_test(data)
  data[:initial_variables] = extract_variables(data[:test])
  actions = []
  begin
    set_trace_func lambda { |event, file, line, id, binding, classname|
      return if !filter_action(event, file, line, id, classname)
      actions << [event, file, line, id, classname]
    }
    data[:test].call
  ensure
    set_trace_func nil
  end
  data[:actions] = actions.uniq
  data[:expected_variables] = extract_variables(data[:test])
end

#check_race_condition(options = {}, &test) ⇒ Object 



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# File 'lib/threading_test_tools.rb', line 90

def check_race_condition(options = {}, &test)
  data = options
  data[:test] = test
  analyze_race_condition_test(data)
  
  assert_raise RaceConditionFound, 'No race condition could be found (with disabled synchronizations).' do
    begin
      $stdout.print '? R3T: Step 1/2 - Try '
      disable_synchronizations
      perform_race_condition_test(data)
    ensure
      $stdout.print "\b" * 22
    end
  end
  
  
  assert_nothing_raised 'An unhandled race condition has been found (with enabled synchronizations).' do
    begin
      begin
        $stdout.print '? R3T: Step 2/2 - Try '
        enable_synchronizations
        perform_race_condition_test(data)
      ensure
        $stdout.print "\b" * 22
      end
    rescue RaceConditionFound => e
      if data[:create_ographs]
        require 'ograph'
        File.open('ograph_expected.dot', 'w') { |file| file.write ObjectGraph.graph(data[:expected_variables]) }
        system('dot -Tpng < ograph_expected.dot > ograph_expected.png')
        File.unlink('ograph_expected.dot')
        File.open('ograph_race_condition.dot', 'w') { |file| file.write ObjectGraph.graph(e.result_variables) }
        system('dot -Tpng < ograph_race_condition.dot > ograph_race_condition.png')
        File.unlink('ograph_race_condition.dot')
      end
      raise e
    end
  end
  
ensure
  $stdout.print ' ' * 40, "\b" * 40
  enable_synchronizations
end

#disable_synchronizations ⇒ Object 



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# File 'lib/threading_test_tools.rb', line 58

def disable_synchronizations
  Object.module_eval <<-CODE_END
    class Mutex
      def lock
        self
      end
    end
    
    module Mutex_m
      def mu_lock
        self
      end
    end
    
    module MonitorMixin
      def mon_enter
        self
      end
    end
    
    module Sync_m
      def sync_lock(m = EX)
        self
      end
    end
  CODE_END
end

#enable_synchronizations ⇒ Object 



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# File 'lib/threading_test_tools.rb', line 38

def enable_synchronizations
  Object.module_eval <<-CODE_END
    class Mutex
      alias_method :lock, :lock_orig
    end
    
    module Mutex_m
      alias_method :mu_lock, :mu_lock_orig
    end
    
    module MonitorMixin
      alias_method :mon_enter, :mon_enter_orig
    end
    
    module Sync_m
      alias_method :sync_lock, :sync_lock_orig
    end
  CODE_END
end

#extract_variables(binding) ⇒ Object 



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# File 'lib/threading_test_tools.rb', line 183

def extract_variables(binding)
  variables = {}
  eval('local_variables', binding).each do |name|
    variables[name] = Marshal.load(Marshal.dump(eval(name, binding)))
  end
  variables
end

#filter_action(event, file, line, id, classname) ⇒ Object 



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# File 'lib/threading_test_tools.rb', line 86

def filter_action(event, file, line, id, classname)
  ['call', 'c-call'].include?(event) && !['threading_test_tools.rb', 'thread.rb', 'thwait.rb', 'mutex_m.rb', 'monitor.rb', 'sync.rb'].include?(File.basename(file))
end

#perform_race_condition_test(data) ⇒ Object 



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# File 'lib/threading_test_tools.rb', line 150

def perform_race_condition_test(data)
  count = data[:actions].size
  digits = count.to_s.length
  0.upto(count - 1) do |index|
    begin
      display = sprintf "%#{digits}d/%#{digits}d", index, count
      $stdout.print display
      $stdout.flush
      action = data[:actions][index]
      restore_variables(data[:test], data[:initial_variables])
      begin
        set_trace_func lambda { |event, file, line, id, binding, classname|
          if action == [event, file, line, id, classname]
            Thread.critical = false
            Thread.pass
            Thread.critical = true
          end
        }
        data[:test].call
        result_variables = extract_variables(data[:test])
      ensure
        set_trace_func nil
      end
      message = []
      if not data[:expected_variables].data_equal?(result_variables, message, {}, true)
        raise RaceConditionFound.new("Race condition found when passing to next thread at #{action[1]}:#{action[2]}: #{message.join}", result_variables)
      end
    ensure
      $stdout.print "\b" * display.size
    end
  end
end

#restore_variables(binding, variables) ⇒ Object 



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# File 'lib/threading_test_tools.rb', line 191

def restore_variables(binding, variables)
  variables.each do |name, value|
    $variable_value = Marshal.load(Marshal.dump(value))
    eval("#{name} = $variable_value", binding)
  end
end