v2ray-core/common/signal/notifier.go

package signal

import "io"

// Notifier is a utility for notifying changes. The change producer may notify changes multiple time, and the consumer may get notified asynchronously.
type Notifier struct {
	c chan struct{}
}

// NewNotifier creates a new Notifier.
func NewNotifier() *Notifier {
	return &Notifier{
		c: make(chan struct{}, 1),
	}
}

// Signal signals a change, usually by producer. This method never blocks.
func (n *Notifier) Signal() {
	select {
	case n.c <- struct{}{}:
	default:
	}
}

// Wait returns a channel for waiting for changes. The returned channel never gets closed.
func (n *Notifier) Wait() <-chan struct{} {
	return n.c
}

type nCloser struct {
	n *Notifier
}

func (c *nCloser) Close() error {
	c.n.Signal()
	return nil
}

func NotifyClose(n *Notifier) io.Closer {
	return &nCloser{
		n: n,
	}
}