Subj : Re: GC question: JS_GetStringBytes
To   : netscape.public.mozilla.jseng
From : Peter Wilson
Date : Sun Aug 28 2005 11:28 am

Brendan Eich wrote:
> Eric Anholt wrote:
>> I'm one of the developers of swfdec, and we've been using the 
>> spidermonkey code for interpreting actionscript with pretty good 
>> success (primary complaint would be the lack of a build system outside 
>> of mozilla that properly builds and installs shared libraries).
> 
> 
> We're taking patches ;-).  There's a bug 
> (https://bugzilla.mozilla.org/show_bug.cgi?id=97954) asking for a 
> unified, standalone, mozilla-style autoconf build setup.  Not sure this 
> will help, but it might.  What OSes are you targeting?
> 
I'd second a request for a standalone build. We're primarily targetting
Linux and OpenBSD.

It's a little while since I looked at this but one of the bigger stumbling
blocks was trying to build spider monkey with multi-thread support using NSPR
so we could have Whitebeam working in multi-threaded Apache 2.

As I remember SpiderMonkey assumed the specific Mozilla source tree
with NSPR having to be in a specific location relative to SpiderMonkey.

I think a standalone build env would also require a stand-alone build
for NSPR to be truly useful.

> 
>> However, while re-reading the code I realized I was being really 
>> sloppy with GC, and I had a couple of questions as a result:
>>
>> - I assume JS_GetStringBytes returns GCed bytes, right?  What is the 
>> guaranteed lifetime of these guys?  If it's "as long as the original 
>> stirng is rooted," I'm fine.
> 
> 
> That's it.
> 
> 
>> - What would you do if you have to maintain a stack of jsvals?  I'm 
>> using a manually rooted JS array and setting jsvals into indexes of 
>> it, but I'm not terribly pleased with this method.
> 
> 
> You might use the interpreter's stack in the current JSContext.  Anent 
> that idea, what are these jsvals for?  When do you push and pop?  Can 
> you bound the size of the stack, or of segments of it that are "chunky" 
> enough to amortize the costs of managing the allocation and deallocation?
> 
> /be

Pete
--
http://www.whitebeam.org
http://www.yellowhawk.co.uk
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