[FFmpeg-soc] [soc]: r5744 - mms/mmst.c

[Bobby Bingham]

On Thu, 8 Apr 2010 12:06:14 -0400
"Ronald S. Bultje" <rsbultje at gmail.com> wrote:

> Hi,
> 
> On Thu, Apr 8, 2010 at 12:02 PM, spyfeng <subversion at mplayerhq.hu> wrote:
> >                             mms->asf_header = av_realloc(mms->asf_header,
> >                                               mms->asf_header_size
> >                                               + mms->pkt_buf_len);
> > -                            if (!mms->asf_header)
> > +                            if (!mms->asf_header) {
> > +                                av_freep(&mms->asf_header);
> >                                 return AVERROR(ENOMEM);
> > +                            }
> >                             memcpy(mms->asf_header + mms->asf_header_size,
> >                                                  mms->pkt_read_ptr,
> >                                                  mms->pkt_buf_len);
> 
> You now this won't work right? :-). You're assigning NULL to a pointer
> and then free'ing it. You'll want to save the return value of
> av_realloc() into a new pointer, check the value, free()
> mms->asf_header if it failed, and else overwrite mms->asf_header.

I haven't looked, but I can imagine that memory leaks arising from this
case aren't all that rare, and it seems a bit unwieldy to need a second
pointer to store the return value every time you call av_realloc.  I
realize it follows the C realloc interface as is, but maybe a wrapper
like this could be useful?

int av_realloc2(void **ptr, size_t size)
{
    void *newptr = av_realloc(*ptr, size);
    if(newptr || size == 0) {
        *ptr = newptr;
        return 0;
    }
    return AVERROR(ENOMEM);
}

> 
> Ronald
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-- 
Bobby Bingham
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