byre/internal/server/hub.go

package server

import (
	"sync"

	"g.fc.run/misc/byre/internal/api"
)

type hub struct {
	mu   sync.Mutex
	subs map[chan api.Event]bool
}

func newHub() *hub {
	return &hub{subs: map[chan api.Event]bool{}}
}

func (h *hub) subscribe() chan api.Event {
	h.mu.Lock()
	defer h.mu.Unlock()
	ch := make(chan api.Event, 256)
	h.subs[ch] = true
	return ch
}

func (h *hub) unsubscribe(ch chan api.Event) {
	h.mu.Lock()
	defer h.mu.Unlock()
	_, ok := h.subs[ch]
	if !ok {
		return
	}
	delete(h.subs, ch)
	close(ch)
}

func (h *hub) publish(ev api.Event) {
	h.mu.Lock()
	defer h.mu.Unlock()
	for ch := range h.subs {
		select {
		case ch <- ev:
		default:
			delete(h.subs, ch)
			close(ch)
		}
	}
}

func (h *hub) count() int {
	h.mu.Lock()
	defer h.mu.Unlock()
	return len(h.subs)
}