[libvirt] [PATCH 3/3] virBuffer: Try harder to free buffer

[Erik Skultety]

On Thu, Apr 18, 2019 at 02:11:25PM +0200, Michal Privoznik wrote:
> Currently, the way virBufferFreeAndReset() works is it relies on
> virBufferContentAndReset() to fetch the buffer content which is
> then freed. This works as long as there is no bug in virBuffer*
> implementation (not true apparently). Explicitly call free() over
> buffer content.
>
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> ---
>  src/util/virbuffer.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/src/util/virbuffer.c b/src/util/virbuffer.c
> index b2ae7963a1..ac03b15a61 100644
> --- a/src/util/virbuffer.c
> +++ b/src/util/virbuffer.c
> @@ -281,9 +281,8 @@ virBufferContentAndReset(virBufferPtr buf)
>   */
>  void virBufferFreeAndReset(virBufferPtr buf)
>  {
> -    char *str = virBufferContentAndReset(buf);
> -
> -    VIR_FREE(str);
> +    if (buf)
> +        virBufferSetError(buf, 0);

You saved 1 call to memset. I also don't see how we can break
virBufferContentAndReset in a way that we couldn't mess up virBufferSetError in
the same way. Additionally, seeing a call to virBufferSetError in a free helper
looks suspicious (even if it has a '0' as argument). If anything, I'd rename
virBuggerFreeAndReset to virBufferClean.

Erik