Subj : GC question
To   : netscape.public.mozilla.jseng
From : lyg
Date : Wed May 26 2004 04:11 pm

I have a puzzling question in my application. My application works like
that:

   it do not support multithread. so I only create one JSContext.

      rt = JS_NewRuntime(JSRUNTIME_SIZE);
      if(!rt)
        return JS_FALSE;
      cx = JS_NewContext(rt, CONTEXT_SIZE);

   I defined a array to contain the created AppObjs.

   JSObject *AppObjPtr[APP_MAX_NUM];
   static int appIndex = 0;

   when I open a new document. I create a object for global object and
rooted it not to be gc.
   {

     if (!(AppObj = JS_NewObject (cx, &AppObj_class, NULL, NULL)))
       return JS_FALSE;

     AppObjPtr[appIndex] = AppObj;
     JS_AddRoot(cx, (void*)(AppObjPtr + appIndex));
     appIndex++;

     JS_InitStandardClasses (cx, AppObj);
     cx->globalObject = AppObj;
     //
       do something else
   }

   when the number of created AppObj is big than APP_MAX_NUM;
   I begin remove all the rooted AppObj and call JS_MaybeGC() to collect the
unavailable gcthings.
   {
       for( k = 0; k < APP_MAX_NUM; k++ )
       {
          JS_RemoveRoot( cx, (void*)(AppObjPtr + k) );
          AppObjectPtr[k] = 0;
       }
       JS_MaybeGC();
   }


   I assigned the JSRUNTIME_SIZE a bigger value about 400k, and i suppose
open APP_MAX_NUM documents need about
   200k. but when i let my application run automaticly, it always met the
condition which rt->gcBytes > rt->gcMaxBytes,
   and obj = NULL;

   /* Allocate an object from the GC heap and zero it. */
    obj = (JSObject *) js_AllocGCThing(cx, GCX_OBJECT);
    if (!obj)
        return NULL;

   Why? is the JS_MaybeGC never be called? Why the created AppObj and its
properties is not freed when I JS_RemoveRoot()?
   what is wrong ?

   thanks very much for any help. and hope somebody can point some error or
unlogical place in my app.

.