Method replyLeaveUnsub

server/topic.go:3431–3516

replyLeaveUnsub is a request to unsubscribe user and detach all user's sessions from topic.

(sess *Session, msg *ClientComMessage, asUid types.Uid)

// replyLeaveUnsub is a request to unsubscribe user and detach all user's sessions from topic.
func (t *Topic) replyLeaveUnsub(sess *Session, msg *ClientComMessage, asUid types.Uid) error {
	now := types.TimeNow()

	if asUid.IsZero() {
		panic("replyLeaveUnsub: zero asUid")
	}

	if t.owner == asUid {
		if msg.init {
			sess.queueOut(ErrPermissionDeniedReply(msg, now))
		}
		return errors.New("replyLeaveUnsub: owner cannot unsubscribe")
	}

	var err error
	var asChan bool
	if msg.init {
		asChan, err = t.verifyChannelAccess(msg.Original)
		if err != nil {
			sess.queueOut(ErrNotFoundReply(msg, now))
			return errors.New("replyLeaveUnsub: incorrect addressing of channel")
		}
	}

	pud := t.perUser[asUid]
	// Delete user's subscription from the database; msg could be nil, so cannot use msg.Original.
	if pud.isChan {
		// Handle channel reader.
		err = store.Subs.Delete(types.GrpToChn(t.name), asUid)
	} else {
		// Handle subscriber.
		err = store.Subs.Delete(t.name, asUid)
	}

	if err != nil {
		if msg.init {
			if err == types.ErrNotFound {
				sess.queueOut(InfoNoActionReply(msg, now))
				err = nil
			} else {
				sess.queueOut(ErrUnknownReply(msg, now))
			}
		}
		return err
	}

	if msg.init {
		sess.queueOut(NoErrReply(msg, now))
	}

	var oldWant types.AccessMode
	var oldGiven types.AccessMode
	if !asChan {
		// Update cached unread count: negative value
		if (pud.modeWant & pud.modeGiven).IsReader() {
			usersUpdateUnread(asUid, pud.readID-t.lastID, true)
		}
		oldWant, oldGiven = pud.modeWant, pud.modeGiven