[Swfdec] Question about SwfdecAsScriptFunction in swfdec

[zou lunkai]

see attached files,  the two files should be placed in the same directory.

A:  functions.swf
B:  movieLoader.swf

--zou




On Thu, Mar 5, 2009 at 4:19 PM, Benjamin Otte <otte at gnome.org> wrote:

> That indeed looks like an oversight. You said you have a testcase for
> this that we can add to the testsuite?
> Could you send that here, so I don't have to code it?
>
> Cheers,
> Benjamin
>
>
> On Thu, Mar 5, 2009 at 3:17 AM, zou lunkai <zoulunkai at gmail.com> wrote:
> > Hello,
> >
> > I got a question about the script function class(SwfdecAsScriptFunction)
> > design in swfdec.
> >
> > Why doesn't a script function mark its
> > target(SwfdecAsScriptFunction::target) in the marking phase?  What if the
> > function's target has been destroyed while the function itself is still
> kept
> > alive? (Answer myself: then there would be  a segfault when executing
> that
> > function)
> >
> > Let me give a more specific case:
> >
> > (1)swf(movie) 'A' defines a script function  'movie_a_func()' inside its
> > body.
> > (2)swf(movie) 'B' loads  movie 'A' at runtime by using
> loadMovieNum('A.swf',
> > 2);
> > (3)movie 'B' then create a reference to function 'movie_a_func()' , eg.
> > movie_b_func = _level2.movie_a_func;
> > (4)unload movie 'A' by using _level2.unloadMovie();
> > (5)next frame;  //Note target of  ''movie_a_func', which is 'A' is
> destroyed
> > and collected here.
> > (6)call function  'movie_b_func';  // bomb, trying to reference its
> > target(movie A) that is already freed.
> >
> > The above case could happen more easily when set GC threshold to
> zero(alway
> > gc).
> >
> > The obvious fix to me is always marking the target of a script function,
> but
> > I am not 100% sure if it's the right way.  It would be helpful if anyone
> > could confirm with me. (BTW, I'v made the real tests described as above.)
> >
> > Yes, I'll file a bug if get confirmed or at least there is someone
> > concerning this mail.
> >
> >
> > --zou
> >
> >
> >
>
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