"io"

// Counter is an io.Writer that increments a counter on Write.

type Counter struct {

	count uint64

func (c *Counter) incr() {

	atomic.AddUint64(&c.count, 1)

// Reset resets the counter.

func (c *Counter) Reset() {

	atomic.StoreUint64(&c.count, 0)

// Count returns the current count.

func (c *Counter) Count() uint64 {

	return atomic.LoadUint64(&c.count)

func (c *Counter) Write(p []byte) (n int, err error) {

// LogCounter creates a LogListener that counts log statements >= the given threshold.

func LogCounter(counter *Counter, t1 Threshold) LogListener {

	return func(t2 Threshold) io.Writer {

		if t2 < t1 {

			// Not interested in this threshold.

			return nil

		}

		return counter