Re: [Libvisual-devel] lvdisplay news

[Dennis S. <sy...@yo...>]

On Sun, 2004-11-21 at 22:38 +0200, Vitaly V. Bursov wrote:
> Hi! :)

HI!! where have you been!, I'm so glad to see that you're back !!!
*YAY!*

> lvdisplay now supports multiple screens :)

Neat! :)


> ======= example/main.c
> 	VisInput *input = visual_input_new("alsa");
>  [snip]
> 	visual_bin_connect(bin, actor, input);
> 	visual_bin_connect(bin2, actor2, input);
>  [snip]
> 	lvdisplay_finalize(v);
> 	lvdisplay_finalize(v2);
> ========

> yup, "input" gets free()'d 2 times. How we're going to fix it?

Ai, I see the problem!

> a. forbid such kind of code. Add input->is_used field to debug it.
> b. add refcounting to input and alike structures and free it accordingly
> 
> I think b. is nice here. Because we have a reentrant design, plugin
> can be used multiple times.... or not?

I agree, we should introduce refcounting. I've got to add something to 
this. What about introducing a VisObject structure, from which every
structure can 'inheritent' by making sure it's allocated in the top of
the struct like I did in VisUI and do ref counting things on a global
scale, something like visual_object_ref, visual_object_unref etc...

We could introduce cast macros so you get something like

VisInput *input = blahblah;
visual_object_unref (VISUAL_OBJECT (input)); to decrease the ref count.

What do you think ?, and are there things I should keep in mind, I
never implemented ref counting before, but I understand the idea...


> and BTW, why not to move -O3 flag to configure scripts and use it only
> when --enable-debug is not passed?

Please go ahead and do this, if you'd like :)

Cheers,
Dennis