From: mark hahn <mchahn@...>
Date: 2001-11-29T06:59:42+09:00
Subject: [ruby-talk:26843] Re: Ref Counting (was KDE or GNOME curiosity question...)

Thanks, that was very clear.

Java also had a "half-dead" state that the finalizer could wake back up
from.  If I remember right there were four total states.

----- Original Message -----
From: "MikkelFJ" <mikkelj-anti-spam@post1.dknet.dk>
Newsgroups: comp.lang.ruby
To: "ruby-talk ML" <ruby-talk@ruby-lang.org>; <undisclosed-recipients:>
Sent: Wednesday, November 28, 2001 1:53 PM
Subject: [ruby-talk:26841] Re: Ref Counting (was KDE or GNOME curiosity
question...)


>
> "mark hahn" <mchahn@facelink.com> wrote in message
> news:004801c17850$95ec4250$2a8bb8d0@web4...
>
> > For example, only references to a File object that rely on the object
> being
> > opened or closed need to be considered when deciding whether the file
can
> be
> > closed at any particular point in time.
>
> Most of these issues can be handled directly by subscribe / unscribe
> semantics of an object. You may keep a link to a subscriber for events,
but
> you can also choose to only maintain a refcount. In any case you perform
> cleanup when the number of subscriptions hits zero. The object may then be
> finalized at a later point - or reused in an object pool.
> This requires no changes, but a general subscriptions Mixin could be
> written - one for refcount and one with event notifications. Very trivial.
>
> related:
> Microfts GC for .NET has some internal confimation logic in the GC. An
> object is finalized before memory is reclaimed. During this process the
> object is parked in a pseudo state where it is neither allocated nor
> dealloced. The object can in the finalization choose to be revived and it
> can modify the heap by allocating objects requring rescans. I don't recall
> the details - its a bit complicated but not that complicated. There is an
> article at MS developer journal on the issue.
> However, their solution does not handle the problem of early finalization.
> You either need compiler scope control or som manual unscribe method.
> You could combine finalize with unsubcribe such that a user object will
> automatically calls unsubscribe on a resource if its owner failed to do
so.
>
> part 1
> http://msdn.microsoft.com/msdnmag/issues/1100/GCI/GCI.asp
> part 2
> http://msdn.microsoft.com/msdnmag/issues/1200/GCI2/GCI2.asp
>
> MikkelFJ
>
>
>