[webkit-dev] ExecState::thisObject()

[Adam Barth]

On Fri, Jul 10, 2009 at 6:29 PM, Maciej Stachowiak<mjs at apple.com> wrote:
> On Jul 10, 2009, at 6:10 PM, Adam Barth wrote:
>> That's correct.  Other browser's get this case right.  Here are a
>> couple test cases you might find interesting:
>>
>> http://webblaze.org/abarth/tests/protoconfused/test1.html
>> http://webblaze.org/abarth/tests/protoconfused/test2.html
>>
>> The question is how to compute the correct wrapper context in all
>> cases.  There are a bunch of approaches that cover 80% of the cases.
>> The trick is finding an approach that works for 100% of the causes.
>
> Well, for DOM Nodes you can almost always chase backpointers all the way up
> to the Document and from there to the Window, but this could be inefficient.
> And there's objects in the DOM that are not Nodes at all, and can't readily
> reach a Node.

We tried this approach for a while, but we came across CSSValue, which
has no obvious back pointers.  It's a bit unclear how to do this for
all Nodes even.  For example, DocType Nodes might not have an
associated Document.

It's possible we could change WebCore to have all the appropriate back
pointers.  However, it might be easier to have all the wrapper objects
hold the global object directly (or indirectly via their heap
placement).

> I will ask Sam and Geoff for their thoughts in person if they don't chime in
> on the list.

Thanks.

Adam