Re: [PATCH v3 5/7] qapi: Introduce QAPI_LIST_APPEND

[Vladimir Sementsov-Ogievskiy]

24.12.2020 01:11, Eric Blake wrote:
> Similar to the existing QAPI_LIST_PREPEND, but designed for use where
> we want to preserve insertion order.  Callers will be added in
> upcoming patches.  Note the difference in signature: PREPEND takes
> List*, APPEND takes List**.
>
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>   include/qapi/util.h | 13 +++++++++++++
>   1 file changed, 13 insertions(+)
>
> diff --git a/include/qapi/util.h b/include/qapi/util.h
> index 6178e98e97a5..8b4967990c0d 100644
> --- a/include/qapi/util.h
> +++ b/include/qapi/util.h
> @@ -37,4 +37,17 @@ int parse_qapi_name(const char *name, bool complete);
>       (list) = _tmp; \
>   } while (0)
>
> +/*
> + * For any pointer to a GenericList @tail, insert @element at the back and
> + * update the tail.

Would be more obvious for me, if directly mention that tail is a pointer to 
'next' field in the last element of the list.

> + *
> + * Note that this macro evaluates @element exactly once, so it is safe
> + * to have side-effects with that argument.
> + */
> +#define QAPI_LIST_APPEND(tail, element) do { \
> +    *(tail) = g_malloc0(sizeof(**(tail))); \
> +    (*(tail))->value = (element); \
> +    (tail) = &(*tail)->next; \
> +} while (0)
> +
>   #endif

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

--
Best regards,
Vladimir