[FFmpeg-devel] [PATCH] avutil/frame: Assert that width/height/channels is 0 for the destination of av_frame*_ref()

[Michael Niedermayer]

On Tue, Mar 08, 2016 at 10:24:55PM -0300, Gonzalo wrote:
> 
> 
> El 08/03/16 a las 17:14, Michael Niedermayer escribió:
> >diff --git a/libavutil/frame.c b/libavutil/frame.c
> >index 5607206..dde32b0 100644
> >--- a/libavutil/frame.c
> >+++ b/libavutil/frame.c
> >@@ -375,6 +375,9 @@ int av_frame_ref(AVFrame *dst, const AVFrame *src)
> >  {
> >      int i, ret = 0;
> >+    av_assert0(dst->width == 0 && dst->height == 0);
> >+    av_assert0(dst->channels == 0);
> >+
> >      dst->format         = src->format;
> >      dst->width          = src->width;
> >      dst->height         = src->height;
> Why does it matter what dst->width/height is originally?  They are
> overwritten right after.

it is to detect if the user calls the functions in the wrong order
which would otherwise trigger memleaks and or undefined behavior

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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