sc.go

type stateChanged struct {
	states     chan State
	register   chan *chan State
	unregister chan *chan State
	observers  map[*chan State]bool
}

func (sc *stateChanged) Register(c *chan State) {
	sc.register <- c
}

func (sc *stateChanged) Unregister(c *chan State) {
	sc.unregister <- c
}

func (sc *stateChanged) run() {
	for {
		select {
		case o := <-sc.register:
			sc.observers[o] = true
		case o := <-sc.unregister:
			delete(sc.observers, o)
			close(*o)
		case s := <-sc.states:
			for o := range sc.observers {
				select {
				case *o <- s:
				default:
					delete(sc.observers, o)
					close(*o)
				}
			}
		}
	}
}