Bug 136809 – TYPE_CASTS_BASE needs to support both for pointer and reference argument by single expression

• Status: NEW
• Component: WebCore Misc.

[Gyuyoung Kim]

As suggested in https://bugs.webkit.org/show_bug.cgi?id=136775#c3, TYPE_CASTS_BASE needs to support .get() globally.

[Darin Adler]

If we really want to make toXXX(RefPtr) give us a raw pointer, then I think toXXX(Ref) and toXXX(PassRef) should give use a raw reference. A good way to do that is to make a template that can take any type and use getPtr to turn the pointer into a raw pointer. That will work on all smart pointer types that we overload getPtr for. Similarly, we could create a getReference to make this generic across all smart reference types. I think that’s better than something specific to RefPtr.

[Gyuyoung Kim]

Darin, there are some specific use cases of TYPE_CASTS_BASE. For example, CSS_BASIC_SHAPES_TYPE_CASTS compares argument type to predicate argument. In this case, it is hard to convert a pointer to a reference using *(X) in the macro.

#define CSS_BASIC_SHAPES_TYPE_CASTS(ToValueTypeName, predicate) \
    TYPE_CASTS_BASE(ToValueTypeName, CSSBasicShape, basicShape, basicShape->type() == predicate, basicShape.type() == predicate) 

Any suggestion about those cases ?

[Darin Adler]

(In reply to comment #2)
> Darin, there are some specific use cases of TYPE_CASTS_BASE. For example, CSS_BASIC_SHAPES_TYPE_CASTS compares argument type to predicate argument. In this case, it is hard to convert a pointer to a reference using *(X) in the macro.
> 
> #define CSS_BASIC_SHAPES_TYPE_CASTS(ToValueTypeName, predicate) \
>     TYPE_CASTS_BASE(ToValueTypeName, CSSBasicShape, basicShape, basicShape->type() == predicate, basicShape.type() == predicate) 
> 
> Any suggestion about those cases ?

I don’t see the problem you are talking about.

    a) basicShape->type() == predicate
    b) basicShape.type() == predicate
    c) (*basicShape).type() == predicate

It seems the macro could use (*x) to use the second expression only and not need (a). Maybe I could advise you on approach if you posted a partial unsuccessful attempt?