[vlc-devel] [PATCH] vlc_es: add more documentation on es_format_Copy

[Rémi Denis-Courmont]

On mercredi 12 juillet 2017 16:51:19 EEST Steve Lhomme wrote:
> It must copy to an unitialized structure or one that was cleaned before.
> 
> The result should always be checked as there are allocations that can fail
> but it's not safe for now given the state of the rest of the code.
> ---
>  include/vlc_es.h | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/include/vlc_es.h b/include/vlc_es.h
> index e9d11d85a8..a428b561c2 100644
> --- a/include/vlc_es.h
> +++ b/include/vlc_es.h
> @@ -627,7 +627,10 @@ VLC_API void es_format_InitFromVideo( es_format_t *,
> const video_format_t * );
> 
>  /**
>   * This functions will copy a es_format_t.
> + *
> + * The destination pointer must be uninitialized or not old any allocated
> buffer. */
> +/* VLC_USED for now we're okay with losing strings and extradata */
>  VLC_API int es_format_Copy( es_format_t *p_dst, const es_format_t *p_src );
> 
>  /**

No. The error is impossible in some code paths (e.g. audio filters), and 
totally harmless in others. Littering the code base with untested, buggy and 
sometimes dead, error code does not make sense.

You can't add VLC_USED then, since ignoring the result is not always a bug.

And video.p_palette should die. And language should be a small fixed size 
character array. That leaves only p_extra IIRC.

-- 
Rémi Denis-Courmont