Method SubscribeConfig

subscription_manager.go:223–267

SubscribeConfig is a special internal Subscribe variant that lets us inject an overridden size.

(config *SubscribeConfig)

// SubscribeConfig is a special internal Subscribe variant that lets us inject
// an overridden size.
func (sm *subscriptionManager) SubscribeConfig(config *SubscribeConfig) (<-chan *Event, func()) {
	if config.ChanSize < 0 {
		panic("SubscribeConfig.ChanSize must be greater or equal to 1")
	}
	if config.ChanSize == 0 {
		config.ChanSize = subscribeChanSizeDefault
	}

	for _, kind := range config.Kinds {
		if _, ok := allKinds[kind]; !ok {
			panic(fmt.Errorf("unknown event kind: %s", kind))
		}
	}

	subChan := make(chan *Event, config.ChanSize)

	sm.mu.Lock()
	defer sm.mu.Unlock()

	// Just gives us an easy way of removing the subscription again later.
	subID := sm.subscriptionsSeq
	sm.subscriptionsSeq++

	sm.subscriptions[subID] = &eventSubscription{
		Chan:  subChan,
		Kinds: sliceutil.KeyBy(config.Kinds, func(k EventKind) (EventKind, struct{}) { return k, struct{}{} }),
	}

	cancel := func() {
		sm.mu.Lock()
		defer sm.mu.Unlock()

		// May no longer be present in case this was called after a stop.
		sub, ok := sm.subscriptions[subID]
		if !ok {
			return
		}

		close(sub.Chan)

		delete(sm.subscriptions, subID)
	}

	return subChan, cancel
}