Class: MutexCounter

Inherits:
Object
  • Object
show all
Defined in:
lib/distributed_logreader/distributer/mutex_counter.rb

Constant Summary collapse

MAX = 
(2 ** 30) - 1

Instance Method Summary collapse

Constructor Details

#initialize(max = MAX) ⇒ MutexCounter

Returns a new instance of MutexCounter.



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# File 'lib/distributed_logreader/distributer/mutex_counter.rb', line 3

def initialize(max = MAX)
  @mutex = Mutex.new
  @counter = 0
  @resets = 0
  @max = max
end

Instance Method Details

#decr ⇒ Object Also known as: pred, prev

decr only to zero



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# File 'lib/distributed_logreader/distributer/mutex_counter.rb', line 32

def decr
  @mutex.synchronize do
    if @counter > 0
      @counter -= 1
    else
      if @resets > 1
        @resets -= 1 
        @counter = @max
      end
    end
    @counter
  end
end

#inc ⇒ Object Also known as: next, succ 



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# File 'lib/distributed_logreader/distributer/mutex_counter.rb', line 19

def inc
  @mutex.synchronize do
    if @counter >= @max
      @counter = 0  # to avoid Bignum, it's about 4x slower
      @resets += 1
    end
    @counter += 1
  end
end

#real_total ⇒ Object Also known as: to_i 



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# File 'lib/distributed_logreader/distributer/mutex_counter.rb', line 10

def real_total
  @mutex.synchronize { (@resets * @max) + @counter }
end

#value ⇒ Object 



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# File 'lib/distributed_logreader/distributer/mutex_counter.rb', line 15

def value
  @mutex.synchronize { @counter }
end