Subj : Re: Garbage Collection Woes
To   : netscape.public.mozilla.jseng
From : "Stephen Jones" <Stephen@Jones-net.com>
Date : Fri Apr 25 2003 03:36 pm

To be more specific:

I have one object that is JS_DefineProperty'd on the global object
another object JS_DefineProperty'd on that
and another object JS_DefineProperty'd on that . . .
then an object that I JS_SetProperty or JS_DefineObject on that one keeps
getting GC'd

example:
root.object1.object2.gcobject
 . . .
shouldn't that be considered "live"

Thanks,
- S

"Stephen Jones" <Stephen@Jones-net.com> wrote in message
news:b8bugv$aen1@ripley.netscape.com...
> I thought I had Garbage Collection in SpiderMonkey figured out, but it
turns
> out I was wrong and I can't figure it out to save my life. I've read all
the
> old posts to this newsgroup regarding Garbage Collection, all the GC tips
on
> the web I can find and it seems to make sense, but it doesn't work and I
> can't figure out what I'm doing wrong.
>
> I was just using JS_AddNamedRoot for everything, but it turns out that
> doesn't work for (probably) obvious reasons. If you have multiple objects
> that are using the same object and one goes out of scope and removes the
> root, then that object is unprotected.
>
> From what I understand, basically, you are supposed to protect object
froms
> GC by setting them as properties on other protected objects. Please
correct
> me if I'm wrong.
>
> So, I have a root object that I "attach" to the global object using
> JS_DefineProperty (I assume that this protects this object, I can't tell
> because I have AddRoots everywhere . . . I'm trying to understand this so
I
> can clean it up). This root object has various properties (defined using
> tiny ids on the prototype of the root object) that are JSObjects as well.
> After an object is instantiated from the prototype (JS_NewObject), to
> protect these objects from GC, I call JS_SetProperty passing in the
> JSObject. This does not work, especially for read-only properties. If I
run
> GC at this point, these objects are destroyed. Note: if I first retrieve
the
> property, then run GC, it is not garbage collected (maybe this is because
it
> is stored in a local root for the return value of the getter?)
>
> Anyway, can someone please set me straight? How should this work? What am
I
> missing?
>
> Thanks,
> - S
>
>

.