Subj : Re: custom object lifetime question.
To   : donteventthinkaboutit
From : Brendan Eich
Date : Tue Jul 20 2004 09:11 am

donteventthinkaboutit@sbcglobal.net wrote:
> Two questions really.
> 
> One:
> I am using JS_DefineObject to create objects of a custom class in my
> application.  Since this isn't a JS_New* function, As far as I can
> gather, I do not need to use JS_AddRoot.  Is this correct?

So long as the object in which you define the property strongly 
referencing the new object created by JS_DefineObject is itself strongly 
connected to the live object graph (either named by another property in 
yet another well-connected live object, or else the object in which you 
defined the new object is rooted explicitly or implicitly).

You can see how liveness depends on being connected to a graph that 
starts from GC roots, both those you define via JS_AddNamedRoot, and 
those implicit in the engine's API (JS_SetGlobalObject and JS_InitClass, 
e.g.).

> Two:
> When my application is done with this object, How do I tell
> spidermonkey that I no longer need it?  It is possible that some
> variables in the runtime may maintain references to this object, even
> after the Native application is done with it, so it cannot be
> destroyed outright.  How do I signal to signal to spidermonkey that
> the  object can now be garbage collected as far as the Native app
> is concerned?

If you use JS_DefineObject, you are (a) creating a new object; (b) 
binding it to another object by defining a property in that other object 
whose value is a reference to the new object created in (a).  If you no 
longer need the object created in (a), you need *at the least* to make 
the object in which you defined it as a property value become garbage, 
or else delete the property defined in (b).

/be

.