Re: [Gnash-dev] Memory allocation model?

[strk]

On Tue, Nov 21, 2006 at 05:25:35PM +0100, Michael Meier wrote:
> Hello
> 
> Is there any documentation about the memory management model in gnash?

Unfortunately not, but looking at the doxygen documentation
(cd doc/C; make apidoc)
you can see which classes derive from ref_counted.
Those classes do support ref-counting.
When you construct a ref_counted class it's initial ref-count is 0.
The reccomandation would be to always store allocated ref_counted
objects to an intrusive_ptr:

boost::intrusive_ptr<as_array_object> array(new as_array_object());

This way you will be sure that the as_array_object will be deleted
when your function returns *unless* somebody else did increment
it's reference counter.

Note that it is *dengerous* not to use the intrusive_ptr. Consider
the following:


        void
        do_something(as_object* obj)
        {
                // store in a smart pointer to keep it
                // alive for whole duration of this function
                {
                        boost::intrusive_ptr<as_objecte> holdit(obj);
                        // ref-count is incremented
                }

                // out of scope, ref-count is decremented,
                // if 0 obj is deleted !
        }

        void
        dangerous()
        {
                as_object* myobj = new as_object(); // ref-count == 0
                do_something(myobj); // WARNING: myobj is not deleted !!!
                as_object* proto = myobj->get_prototype();
        }


--strk;