Bug 254864 – Implement [AllowShared] suport in Web IDL

• Status: NEW
• Component: DOM

[Anne van Kesteren]

It seems that we currently don't throw in places that are not supposed to take shared memory: https://wpt.fyi/results/xhr/send-data-sharedarraybuffer.any.html.

[Radar WebKit Bug Importer]

<rdar://problem/107786134>

[Anne van Kesteren]

Per https://github.com/WebKit/WebKit/commit/02a7ddd1949f734535c90d93a6d10eea06afcdce#diff-93b28dd1c69f1ae018f811d9fa195b7ccff18e02ffca56c1864ba79ebbe56b30 we have at least some support for [AllowShared], so why does the IDL layer not end up throwing here?

Yusuke, do you know?

[Yusuke Suzuki]

(In reply to Anne van Kesteren from comment #2)
> Per
> https://github.com/WebKit/WebKit/commit/
> 02a7ddd1949f734535c90d93a6d10eea06afcdce#diff-
> 93b28dd1c69f1ae018f811d9fa195b7ccff18e02ffca56c1864ba79ebbe56b30 we have at
> least some support for [AllowShared], so why does the IDL layer not end up
> throwing here?
> 
> Yusuke, do you know?

I have no idea, probably XHR is not using AllowShared.

[Yusuke Suzuki]

(In reply to Yusuke Suzuki from comment #3)
> (In reply to Anne van Kesteren from comment #2)
> > Per
> > https://github.com/WebKit/WebKit/commit/
> > 02a7ddd1949f734535c90d93a6d10eea06afcdce#diff-
> > 93b28dd1c69f1ae018f811d9fa195b7ccff18e02ffca56c1864ba79ebbe56b30 we have at
> > least some support for [AllowShared], so why does the IDL layer not end up
> > throwing here?
> > 
> > Yusuke, do you know?
> 
> I have no idea, probably XHR is not using AllowShared.

It is probably largely depending on how XHR is implementing send function, I guess.

[Anne van Kesteren]

I think I figured it out. What happens is that we apply ToString because we treat them as distinct types which does not quite match https://webidl.spec.whatwg.org/#js-union

I think this is correct for SharedArrayBuffer now that SharedArrayBuffer is a standalone type in Web IDL (though this might need more discussion), but this is incorrect for views on a SharedArrayBuffer.