[Sugar-devel] [sugar-web] do webkit frames run on different threads?

[Code Raguet]

I've read the following, recently:
[...]

> In Opera, every window has its own JavaScript thread. This includes
> windows in iframes. The consequence is that event handlers initiated from
> different frames might execute at the same time. If these simultaneous
> scripts modify shared data (like properties in the top window), we have the
> possibility of race conditions.

[...]
source:
http://dev.opera.com/articles/view/timing-and-synchronization-in-javascript/

Because some pieces of sugar-web API ( for ex: env.js) relay on window.top
props (and karma loads a context.html iframe and runs the specs within), I
asked to myself if webkit frames may simultaneously run on different
threads...

I always think in a single-threaded model when programming javascript
(async, of course, but not multithreading). Therefore, It seems to me like
an Opera specific.
After a little research, I wasn't able to find an concrete answer, so asked
Roger to try out some tests.

We made a long running function with busy waiting loops that mutates a
shared porp at window.top and then we ran it twice (one per frame) in
Opera. As the doc says, we 've been able to make a (racy) non-deterministic
state of the shared prop.[?]

Same tests on Chrome showed single-thread behavior... [?]

So the thesis would be running those on webkit... but we haven't yet
We had some unrelated issues and before keep digging I want ask you what do
you think/know about...

Thanks,
Code
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