veryroundbird.house
1package notifier
2
3import (
4 "sync"
5)
6
7type Notifier struct {
8 subscribers map[chan struct{}]struct{}
9 mu sync.Mutex
10}
11
12func New() Notifier {
13 return Notifier{
14 subscribers: make(map[chan struct{}]struct{}),
15 }
16}
17
18func (n *Notifier) Subscribe() chan struct{} {
19 ch := make(chan struct{}, 1)
20 n.mu.Lock()
21 n.subscribers[ch] = struct{}{}
22 n.mu.Unlock()
23 return ch
24}
25
26func (n *Notifier) Unsubscribe(ch chan struct{}) {
27 n.mu.Lock()
28 delete(n.subscribers, ch)
29 close(ch)
30 n.mu.Unlock()
31}
32
33func (n *Notifier) NotifyAll() {
34 n.mu.Lock()
35 for ch := range n.subscribers {
36 select {
37 case ch <- struct{}{}:
38 default:
39 // avoid blocking if channel is full
40 }
41 }
42 n.mu.Unlock()
43}