[FFmpeg-devel] [PATCH] avutil/common: add FFRET/FFGOTO macro

[Hendrik Leppkes]

On Tue, Dec 20, 2016 at 10:38 AM, Muhammad Faiz <mfcc64 at gmail.com> wrote:
> FFRET_ERR and FFGOTO_ERR for common error handling
> FFRET_OOM and FFGOTO_OOM for oom handling
>
> Signed-off-by: Muhammad Faiz <mfcc64 at gmail.com>
> ---
>  libavutil/common.h | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>
> diff --git a/libavutil/common.h b/libavutil/common.h
> index 8142b31..b868d60 100644
> --- a/libavutil/common.h
> +++ b/libavutil/common.h
> @@ -99,6 +99,29 @@
>  #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
>  #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
>
> +/* Common error handling */
> +#define FFRET_ERR(val, ...)             \
> +    do {                                \
> +        int ffret_err_ret__ = (val);    \
> +        if (ffret_err_ret__ < 0) {      \
> +            __VA_ARGS__;                \
> +            return ffret_err_ret__;     \
> +        }                               \
> +    } while (0)
> +
> +#define FFGOTO_ERR(val, ret, dst, ...)  \
> +    do {                                \
> +        int ffgoto_err_ret__ = (val);   \
> +        if (ffgoto_err_ret__ < 0) {     \
> +            ret = ffgoto_err_ret__;     \
> +            __VA_ARGS__;                \
> +            goto dst;                   \
> +        }                               \
> +    } while (0)
> +
> +#define FFRET_OOM(val, ...) FFRET_ERR((val) ? 0 : AVERROR(ENOMEM), __VA_ARGS__)
> +#define FFGOTO_OOM(val, ret, dst, ...) FFGOTO_ERR((val) ? 0 : AVERROR(ENOMEM), ret, dst, __VA_ARGS__)
> +

I don't really like these. Passing code to a macro as vaargs is iffy
at best and make it rather hard to read, and ultimately doesn't make
the code any simpler imho, which the goal should be.

- Hendrik