Method subscribeLocked

nats.go:4893–4967

(subj, queue string, cb MsgHandler, ch chan *Msg, errCh chan (error), isSync bool, js *jsSub)

}

func (nc *Conn) subscribeLocked(subj, queue string, cb MsgHandler, ch chan *Msg, errCh chan (error), isSync bool, js *jsSub) (*Subscription, error) {
	if nc == nil {
		return nil, ErrInvalidConnection
	}
	if badSubject(subj) {
		return nil, ErrBadSubject
	}
	if queue != _EMPTY_ && badQueue(queue) {
		return nil, ErrBadQueueName
	}

	// Check for some error conditions.
	if nc.isClosed() {
		return nil, ErrConnectionClosed
	}
	if nc.isDraining() {
		return nil, ErrConnectionDraining
	}

	if cb == nil && ch == nil {
		return nil, ErrBadSubscription
	}

	sub := &Subscription{
		Subject: subj,
		Queue:   queue,
		mcb:     cb,
		conn:    nc,
		jsi:     js,
	}
	// Set pending limits.
	if ch != nil {
		sub.pMsgsLimit = cap(ch)
	} else {
		sub.pMsgsLimit = DefaultSubPendingMsgsLimit
	}
	sub.pBytesLimit = DefaultSubPendingBytesLimit

	// If we have an async callback, start up a sub specific
	// Go routine to deliver the messages.
	var sr bool
	if cb != nil {
		sub.typ = AsyncSubscription
		sub.pCond = sync.NewCond(&sub.mu)
		sr = true
	} else if !isSync {
		sub.typ = ChanSubscription
		sub.mch = ch
	} else { // Sync Subscription
		sub.typ = SyncSubscription
		sub.mch = ch
		sub.errCh = errCh
	}

	nc.subsMu.Lock()
	nc.ssid++
	sub.sid = nc.ssid
	nc.subs[sub.sid] = sub