I was suggesting QtPrivate::, since QFutureInterface/QFutureInterfaceBase aren’t public and access to QFuture’s d-ptr is not something we would want to recommend generally, I don’t think the average user will need it. But, of course, the exact API can be discussed.
Best regards, Sona From: Konstantin Ritt <ritt...@gmail.com> Sent: Saturday, May 8, 2021 6:26 PM To: Sona Kurazyan <sona.kuraz...@qt.io> Cc: Arno Rehn <a.r...@menlosystems.com>; Qt development mailing list <development@qt-project.org> Subject: Re: [Development] QMetaType support for QFuture Can't we simply `QFutureInterface(const QFuture<T> &future)` to get that future's QFutureInterface, w/o any QtPrivate:: ugliness? Regards, Konstantin сб, 8 мая 2021 г. в 11:30, Sona Kurazyan <sona.kuraz...@qt.io<mailto:sona.kuraz...@qt.io>>: Hi Konstantin, QFuture has a constructor for QFuture<void> from QFuture<T>, see https://code.qt.io/cgit/qt/qtbase.git/tree/src/corelib/thread/qfuture.h#n82, so you don’t even need to use the broken qToVoidFuture() method. I’ll probably remove it, since it was always broken and couldn’t be ever used. I can see that in some special use-cases having access to QFuture’s internals might be useful, but this is not something we would recommend to do to all users. That’s why, I think, adding an API that gives access to QFuture’s d-ptr (as it was suggested earlier) might be an option. Best regards, Sona From: Konstantin Ritt <ritt...@gmail.com<mailto:ritt...@gmail.com>> Sent: Saturday, May 8, 2021 2:29 AM To: Arno Rehn <a.r...@menlosystems.com<mailto:a.r...@menlosystems.com>> Cc: Sona Kurazyan <sona.kuraz...@qt.io<mailto:sona.kuraz...@qt.io>>; Qt development mailing list <development@qt-project.org<mailto:development@qt-project.org>> Subject: Re: [Development] QMetaType support for QFuture I was implementing a similar feature few years ago and had the same problem with QFuture internals -- https://codereview.qt-project.org/c/qt/qtbase/+/210243 As there was no interest in making those better, I had to hack it in a way I won't promote here ;p But since QFuture took a new life with QPromise, it becomes even more useful than before and deserves some improvements IMO. Maybe we could add a public accessor to future's d via QFutureInterfaceBase? Will that be acceptable? Regards, Konstantin пт, 7 мая 2021 г. в 19:28, Arno Rehn <a.r...@menlosystems.com<mailto:a.r...@menlosystems.com>>: Hi Sona, On 07.05.21 17:11, Sona Kurazyan wrote: > You could use the QFutureInterfaceBase (non-templated) class directly > to build a type-erased future, that's basically what QFuture is using > underneath. Although it's internal (not documented and is considered > to be private), but it's declared in a public header > (qfutureinterface.h) and you can still use it. QFutureInterfaceBase's > methods for accessing its internals are public (with a few exceptions > that you probably won't need to use). I hope that helps. Yep, that's what I thought as well. But I cannot get it from an existing QFuture because it's a private member. We could add some private API to extract the QFutureInterfaceBase, however. Anyway, I think I'll have to add some QMetaType magic anyway for this to work. In QtWebChannel, we get the method return value wrapped in a QVariant, so the QFuture<T> is wrapped in a QVariant. From there, I cannot extract the QFutureInterfaceBase in any way. I *could* just memcpy from QVariant's data pointer to a QFutureInterfaceBase*, but I'm pretty sure that this is UB. Any pointer where to start? Regards, Arno -- Arno Rehn Tel +49 89 189 166 0 Fax +49 89 189 166 111 a.r...@menlosystems.com<mailto:a.r...@menlosystems.com> www.menlosystems.com<http://www.menlosystems.com> Menlo Systems GmbH Bunsenstrasse 5, D-82152 Martinsried, Germany Amtsgericht München HRB 138145 Geschäftsführung: Dr. Michael Mei, Dr. Ronald Holzwarth USt.-IdNr. DE217772017, St.-Nr. 14316170324 _______________________________________________ Development mailing list Development@qt-project.org<mailto:Development@qt-project.org> https://lists.qt-project.org/listinfo/development
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