Remove the `wrap_fn` argument from `reflect_dom_object`.

[Ms2ger]

It should be possible to derive it from the type. Maybe FooBinding::Wrap should be <Foo as ConcreteDOMObject>::wrap? (Name of the trait up for bikeshedding.)

[nox]

This obviously exclude global interfaces, which don't have the same wrap signature. Maybe we should also have a reflect_dom_global function with that other wrap?

[Ms2ger]

Orthogonal to this issue, but that sounds like something we could do, yes.

[jooh-kim]

@jdm hi can i try this issue?

[jdm]

@kjhyung Of course! Ask questions about anything that's unclear!

[jdm]

@kjhyung Have you made any progress on this task?

[lyuyuan]

@jdm May I have a try on this if no one is working on it now?

[jdm]

@lyuyuan Sure! I think the easiest way to proceed is to:

• add an associated const to the DomObject trait which is a function pointer to the general wrap function type (https://doc.servo.org/script/dom/bindings/codegen/Bindings/ANGLEInstancedArraysBinding/ANGLEInstancedArraysBinding/fn.Wrap.html, using Self instead of ANGLEInstancedArrays)
• modify the output of #[dom_struct] (https://github.com/servo/servo/blob/master/components/dom_struct/lib.rs) to produce an implementation of DomObject that includes the new associated constant (using crate::dom::codegen::Bindings::[name]Bindings::Wrap for a type named [name])
• remove the wrap_fn argument from reflect_dom_object and use T::WRAP instead (assuming the new associated constant is called WRAP)

Does that make sense?

[lyuyuan]

@jdm Sounds good! Thanks for the tip!

[lyuyuan]

@jdm It seems that DomObject trait cannot contain associated constants (E0038) because it is FormControl's supertrait and FormControl is used in a trait object here.
If I understand the workaround correctly, I need to add a helper method in DomObject which returns the function pointer, WRAP. Does this sounds correct? Thanks!

[jdm]

I think we can get away with a different solution:

trait DomObjectWrap {
    const WRAP: ...
}

And edit https://github.com/servo/servo/blob/master/components/dom_struct/lib.rs#L42-L53 to implement the DomObjectWrap trait, and make reflect_dom_object take T: DomObject + DomObjectWrap.