[Development] Undeprecating QPointer

[Thiago Macieira]

On sexta-feira, 2 de março de 2012 12.20.05, Olivier Goffart wrote:
> > I'd like to suggest we un-deprecate it and bring it back to full status.
> 
> I agree.

Anyone objects?

> I have been trying to compile qtbase without the deprecated symbols, and two
> issues remains that i could not solve: QPointer, and QWheelEvent's
> deprecated member.

There's also the QImageTextLang deprecation, but I've got a patch for that. It 
basically involves deprecating the constructors instead of the entire type.

> The alternative would be to add operator-> and operator T* to QWeakPointer,
> which would allow do do simply s/QPointer/QWeakPointer/g
> I personaly beleive this would actually be the best option.

I don't, because that would detract from QWeakPointer's original mission. 
You're not supposed to access the pointer stored in a QWeakPointer without 
first promoting it to QSharedPointer. The .data() access was a concession to 
handling QObjects when QPointer was hellish slow in Qt 4.

> > At the same time, I'd like to suggest we discourage using QWeakPointer for
> > tracking QObjects, instead leaving it to its original purpose of being the
> > weak reference counterpart to QSharedPointer.
> 
> Indeed, we should not have two class with the same purpose. So if QPointer
> stays, QWeakPointer have to leave.

"Leave" in the sense of "stop handling QObjects". It has another, main purpose 
which means it stays undeprecated.

> > I'm not going as far as suggesting we deprecate the QWeakPointer(QObject*)
> > constructor yet. I need to do a bit of research on how a future
> > QSharedPointer & QWeakPointer with full "enable_shared_from_this" and
> > QObject tracking would look like.
> 
> One problem: QPointer use QWeakPointer inline, meaning it can hardly be done
> without QWeakPointer in the future.

True, but QPointer might as well use some of the internals and avoid warnings.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center
     Intel Sweden AB - Registration Number: 556189-6027
     Knarrarnäsgatan 15, 164 40 Kista, Stockholm, Sweden
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