Re: [Gnash-dev] Re: gotoAndPlay bug in Gnash

[Eric Hughes]

At 09:40 AM 5/9/2007, Martin Guy wrote:
> > The proprietary player doesn't indeed have any timeline control, any
> > timeline control is implemented by the SWF application itself.
>
> In that case maybe neither should we, and dump the advance/retreat control.
> It's a bit like asking for a rewindable computer game... unless
> someone can figure out what it means to rewind a flash movie.

I basically agree with this position.  For arbitrary code, the only way in 
general to rewind it is to record its execution history and replay _that_ 
in reverse, ignoring the code that generated said history.  Sure, it will 
suck memory.  It's an expensive operation.

I do see a use for such a functionality, specifically for authors to 
inspect the execution of their code.  The right schedule-time to implement 
this is not for an end-user player, but when building up a full development 
environment.  Such functionality seems premature rather than never-needed 
to my eye.

Did I say arbitrary code--the same phrase relevant in 
security?  Yep.  Beware, beware, beware.

I also see the utility of being able to rewind simple scripts, for some 
certainly-yet-to-be-determined definition of "simple".  On the other hand, 
I will shout that until the general reversal problem is well-understood, DO 
NOT ATTEMPT THIS.  Such an effort would be a security-defect-generator of 
the very worst sort.

To summarize my opinion today:
-- Item "development suite" blocks item "full reversibility".
-- Item "full reversibility" blocks item "partial reversibility".
I recommend no immediate action on this issue, except to deactivate the 
rewind button for scripts and get back to safety.

Eric