[Gnash-dev] Re: GC: static (kept alive) resources

[zou lunkai]

On 6/26/07, strk <address@hidden> wrote:
> > you should have more comprehensive understandings about GC, so you
> > make the final decision:)
>
> Please help  :)
> If you need more info just ask and I'll explain.
> Note that the current design is aimed at keeping both RC and GC an option
> for a quick backup solution.
OK, I do still have some questions about the GC, based on the
information on wiki

"
Collection algorithm
The algorithm will be around these lines:

  1. INITIALIZATION: all managed objects are constructed in the
UNREACHABLE state, no scan needed for initialization.
  2. MARK SCAN: for each reachable object, if the object isn't marked
as REACHABLE then mark it so and recurse.
  3. CLEANUP SCAN: Release all resources which are still markes as
UNREACHABLE, mark the remaining as UNREACHABLE to be ready for next
scan.

"
In step 1, if all objects are construted as UNREACHABLE, who make them
to be  REACHABLE? I don't see this happen in step 2 and 3.

In step2, where are the "reachable objects"?  Since all objects in
step1 are UNREACHABLE,  after you step to step2 from step1, all
objects constructed in step1 are still UNREACHABLE as I see.  Answerer
question one would also answer this.

I just can not stop thinking about the GC algorithm intuitively in my
brain like this:

1. INITIALIZATION: all managed objects are constructed in the
REACHABLE state, no scan needed for initialization.
2. MARK: mark the specified object to be UNREACHABLE  in the REACHABLE
object list. (This is done by user)
3. CLEANUP SCAN:  Release all resources which are marked as
UNREACHABLE, keep the REACHABLE objects alive.

These are some assumptions I made, which might lead my
misunderstanding about the GC algorithm, I need your check.
(1)An object is reachable means it is in a valid state and can be
accessed by the user, otherwise not.
(2)An object is unreachable after it is deleted or a deletion
instruction be issured on it.
(3)If I create a new object, of course I need it to be reachable,
since I might need to use it immediately.

Thanks!

zou