SingleShot-connection: will I get memory leaks like this?

themts

Hey guys,

I've implemented a single-shot connection with timeout and I'm not completely sure if I will run into memory leaks.

//weak-connect to a functor with timeout
template <typename Func1, typename Func2, typename Func3>
static inline typename QtPrivate::QEnableIf<QtPrivate::FunctionPointer<Func2>::ArgumentCount == -1, QMetaObject::Connection>::Type
        weakConnect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 slot, uint timeout, Func3 timeoutSlot)
{
    QMetaObject::Connection conn_normal = QObject::connect(sender, signal, sender, slot, Qt::DirectConnection);
    QMetaObject::Connection* conn_delete = new QMetaObject::Connection();
    QTimer* timer = NULL;

    *conn_delete = QObject::connect(sender, signal, [conn_normal, conn_delete](){
        if (timer) {
            timer->stop();
            timer->deleteLater();
        }

        QObject::disconnect(conn_normal);
        QObject::disconnect(*conn_delete);
        delete conn_delete;
    });

    if (timeout > 0) {
        timer = new QTimer;
        timer->setSingleShot(true);
        timer->setInterval(timeout);

        QObject::connect(timer, &QTimer::timeout, [conn_normal, conn_delete, timer, timeoutSlot] () {
            QObject::disconnect(conn_normal);
            QObject::disconnect(*conn_delete);
            delete conn_delete;

            timer->deleteLater();
            timeoutSlot();
        });
        timer->start();
    }

    return conn_normal;
}

you can call it like that

    weakConnect(engine, &Engine::positionReached, [&](bool reached) {
        ///fired if signal is emitted within 1000ms
    }, 1000, [&] {
        //fired if signal is NOT emitted within 1000ms
    });

The idea was to have a simple single-use connection with lamda-expressions.
I'm not completely sure if I will run into memory-leaks?
deleteLater() needs an eventloop. What if it's called outside an event-loop? Could I delete the timer the timeout-slot by delete(timer)?

taedium

@themts said in SingleShot-connection: will I get memory leaks like this?:

deleteLater() needs an eventloop. What if it's called outside an event-loop? Could I delete the timer the timeout-slot by delete(timer)?

Yes, you could (I don't see why necessarily using a deleteLater here). Save that it looks good to me.