[webkit-dev] GlobalScript in WebKit
mjs at apple.com
Mon Nov 30 17:21:34 PST 2009
On Nov 30, 2009, at 5:09 PM, Maciej Stachowiak wrote:
> On Nov 30, 2009, at 4:35 PM, Jeremy Orlow wrote:
>> To be fair, app developers in general want to do everything
>> synchronously but we (in standards land) have pushed back very hard
>> because software research has shown that such interfaces are very
>> difficult (if not impossible) to parallelize. That's why
>> SharedScript sidesteps the issue by saying there should be no
>> parallelism. Which really is a step backwards.
> Now that I've heard more about it, it seems like SharedScript gives
> the worst of both worlds by encouraging synchronous coding but
> potentially still resulting in unexpected parallelism. It seems like
> for correctness you'd have to write nearly the exact same multiple-
> instance anti-collision code in your SharedScript that you would in
> each main document if you didn't have SharedScript.
By the way, we could enable the SharedScript programming model at much
lower WebKit-level implementation cost and with much less API surface
- Allow Window to be passed via the structured clone algorithm over a
MessageChannel, but it throws on all access if the recipient is not
same-origin, in the same thread, and eligible for synchronous calls
(i.e. in the same process).
I believe this would allow SharedScript to be implemented in
elect a leader Window within each same-process group, which could then
object does not get GC'd until all the referencing windows go away.
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