func()

in rate/rate.go [223:266]

• 36 lines of code
• 9 McCabe index (conditional complexity)

func (lim *Limiter) WaitN(ctx context.Context, n int) (err error) {
	lim.mu.Lock()
	burst := lim.burst
	limit := lim.limit
	lim.mu.Unlock()

	if n > burst && limit != Inf {
		return fmt.Errorf("rate: Wait(n=%d) exceeds limiter's burst %d", n, burst)
	}
	// Check if ctx is already cancelled
	select {
	case <-ctx.Done():
		return ctx.Err()
	default:
	}
	// Determine wait limit
	now := time.Now()
	waitLimit := InfDuration
	if deadline, ok := ctx.Deadline(); ok {
		waitLimit = deadline.Sub(now)
	}
	// Reserve
	r := lim.reserveN(now, n, waitLimit)
	if !r.ok {
		return fmt.Errorf("rate: Wait(n=%d) would exceed context deadline", n)
	}
	// Wait if necessary
	delay := r.DelayFrom(now)
	if delay == 0 {
		return nil
	}
	t := time.NewTimer(delay)
	defer t.Stop()
	select {
	case <-t.C:
		// We can proceed.
		return nil
	case <-ctx.Done():
		// Context was canceled before we could proceed.  Cancel the
		// reservation, which may permit other events to proceed sooner.
		r.Cancel()
		return ctx.Err()
	}
}