frontend: Use qobject_cast when casting QObjects

[cg2121]

Description

When casting between QObjects, qobject_cast should always be used. This increases performance as there is no RTTI (Run Time Type Information) with qobject_cast, like there is with dynamic_cast.

Using reinterpret_cast is bad practice, as you should use it only in very specific cases.

Motivation and Context

Better code

How Has This Been Tested?

compiled and ran OBS

Types of changes

• Bug fix (non-breaking change which fixes an issue) -->
• Performance enhancement (non-breaking change which improves efficiency)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[cg2121]

Converting to draft, as #11785 needs to be merged first.

[cg2121]

This PR now builds correctly

[PatTheMav]

Overall I'm fine with this change, though it obviously touches a whole lot casts in the code that touch a whole lot of aspects of our frontend code, so this might be too late for the next version but should possibly merged after the next version is stabilised to give it some time to exist on the master branch.

@RytoEX WDYT?

[RytoEX]

Overall I'm fine with this change, though it obviously touches a whole lot casts in the code that touch a whole lot of aspects of our frontend code, so this might be too late for the next version but should possibly merged after the next version is stabilised to give it some time to exist on the master branch.

@RytoEX WDYT?

I think this should be merged for 32.1, merge timing TBD. It does have a merge conflict though.

[Warchamp7]

I've rebased this PR

[gxalpha]

Just looking at it, I think most of these should use static_cast instead of either dynamic_cast or qobject_cast. qobject_cast is better than dynamic_cast if you want the dynamic behavior (i.e. have the object be null if the cast fails), but if you already know/assume that the cast will succeed (and dont check for new_obj == nullptr), you can just use static_cast.

Also, original git commit authorship appears to have gotten lost, that should probably be reverted.

[Warchamp7]

Just looking at it, I think most of these should use static_cast instead of either dynamic_cast or qobject_cast. qobject_cast is better than dynamic_cast if you want the dynamic behavior (i.e. have the object be null if the cast fails), but if you already know/assume that the cast will succeed (and dont check for new_obj == nullptr), you can just use static_cast.

Also, original git commit authorship appears to have gotten lost, that should probably be reverted.

Adjusted the PR for this, as well as removed a macro in the AutoConfig files that were casting the wizard() method in favor of an inline method on those pages.

[PatTheMav]

Does it make sense to call autoConfig() here for every single line instead setting up a local variable that holds the reference to the widget?

It doesn't seem like it's expected for that object to change between all those function calls.