[Fwd: Re: Keeping oops across primitives]

Oops, I sent this accidentally only to Bryce...

-------- Original Message --------
Subject: Re: Keeping oops across primitives
Date: Thu, 08 Jun 2006 10:50:54 -0700
From: Andreas Raab <[hidden email]>
To: Bryce Kampjes <[hidden email]>
References: <[hidden email]>
<[hidden email]>

Hi Bryce -

Actually, this is an interesting thought. I have the need for managing a
dynamic array of roots but this could be handled just as easily by
tracking a variable pointing to a Squeak array.

So, does anyone feel strongly about going either way?

Cheers,
   - Andreas

Andreas Raab wrote:
> Actually, this is an interesting thought. I have the need for managing a
> dynamic array of roots but this could be handled just as easily by
> tracking a variable pointing to a Squeak array.

A variable in C is more-or-less a one-place array, so perhaps supporting
arrays is the simpler option?

{
  sqInt myRoot = ...;
  vm->addToVmRoots(&myRoot, 1, NULL);
  ...
  vm->addToVmRoots(NULL, 0, &myRoot);
}



#define WITH_ROOT(vm, var, blk) \
  { (vm)->addToVmRoots(&(var), 1, NULL); \
    blk; \
    (vm)->addToVmRoots(NULL, 0, &(var)); }

{
  sqInt myRoot2 = ...;
  WITH_ROOT(vm, myRoot2, {
    ...
  });
}

Tony Garnock-Jones wrote:
> Andreas Raab wrote:
>> Actually, this is an interesting thought. I have the need for managing a
>> dynamic array of roots but this could be handled just as easily by
>> tracking a variable pointing to a Squeak array.
>
> A variable in C is more-or-less a one-place array, so perhaps supporting
> arrays is the simpler option?

Turns out not. The code is much simpler supporting just individual oop
locations (variables) so I decided to go with the following interface:

sqInt oopVar; /* declare a global that we wish to track */

{
   ...
   oopVar = vm->nilObject(); /* don't forget to initialize it !!! */
   vm->addGCRoot(&oopVar); /* update it */
   ...
}

and to undo that

{
   ...
   vm->removeGCRoot(&oopVar);
   ...
}

Cheers,
   - Andreas