[FFmpeg-devel] [PATCH 4/5] ffmpeg: Allow printing of option arguments in help output

[Andreas Rheinhardt]

Thilo Borgmann:
> ---
>  fftools/cmdutils.c |  5 +++++
>  libavutil/opt.c    | 14 +++++++++++++-
>  libavutil/opt.h    |  8 ++++++++
>  3 files changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/fftools/cmdutils.c b/fftools/cmdutils.c
> index 22ba654bb0..dae018f83a 100644
> --- a/fftools/cmdutils.c
> +++ b/fftools/cmdutils.c
> @@ -172,6 +172,11 @@ void show_help_options(const OptionDef *options, const char *msg, int req_flags,
>              av_strlcat(buf, po->argname, sizeof(buf));
>          }
>          printf("-%-17s  %s\n", buf, po->help);
> +
> +        if (po->args) {
> +            const AVClass *p = po->args;
> +            av_arg_show(&p, NULL);
> +        }
>      }
>      printf("\n");
>  }
> diff --git a/libavutil/opt.c b/libavutil/opt.c
> index a3940f47fb..89ef111690 100644
> --- a/libavutil/opt.c
> +++ b/libavutil/opt.c
> @@ -1256,7 +1256,7 @@ static void opt_list(void *obj, void *av_log_obj, const char *unit,
>              av_log(av_log_obj, AV_LOG_INFO, "     %-15s ", opt->name);
>          else
>              av_log(av_log_obj, AV_LOG_INFO, "  %s%-17s ",
> -                   (opt->flags & AV_OPT_FLAG_FILTERING_PARAM) ? " " : "-",
> +                   (opt->flags & (AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_ARGUMENT)) ? " " : "-",
>                     opt->name);
>  
>          switch (opt->type) {
> @@ -1329,6 +1329,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
>                  av_log(av_log_obj, AV_LOG_INFO, "%-12s ", "");
>                  break;
>          }
> +        if (!(opt->flags & AV_OPT_FLAG_ARGUMENT)) {
>          av_log(av_log_obj, AV_LOG_INFO, "%c%c%c%c%c%c%c%c%c%c%c",
>                 (opt->flags & AV_OPT_FLAG_ENCODING_PARAM)  ? 'E' : '.',
>                 (opt->flags & AV_OPT_FLAG_DECODING_PARAM)  ? 'D' : '.',
> @@ -1341,6 +1342,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
>                 (opt->flags & AV_OPT_FLAG_BSF_PARAM)       ? 'B' : '.',
>                 (opt->flags & AV_OPT_FLAG_RUNTIME_PARAM)   ? 'T' : '.',
>                 (opt->flags & AV_OPT_FLAG_DEPRECATED)      ? 'P' : '.');
> +        }
>  
>          if (opt->help)
>              av_log(av_log_obj, AV_LOG_INFO, " %s", opt->help);
> @@ -1456,6 +1458,16 @@ int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags)
>      return 0;
>  }
>  
> +int av_arg_show(void *obj, void *av_log_obj)
> +{
> +    if (!obj)
> +        return -1;
> +
> +    opt_list(obj, av_log_obj, NULL, AV_OPT_FLAG_ARGUMENT, 0, -1);
> +
> +    return 0;
> +}
> +
>  void av_opt_set_defaults(void *s)
>  {
>      av_opt_set_defaults2(s, 0, 0);
> diff --git a/libavutil/opt.h b/libavutil/opt.h
> index 461b5d3b6b..dce3483237 100644
> --- a/libavutil/opt.h
> +++ b/libavutil/opt.h
> @@ -297,6 +297,7 @@ typedef struct AVOption {
>  #define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering
>  #define AV_OPT_FLAG_DEPRECATED      (1<<17) ///< set if option is deprecated, users should refer to AVOption.help text for more information
>  #define AV_OPT_FLAG_CHILD_CONSTS    (1<<18) ///< set if option constants can also reside in child objects
> +#define AV_OPT_FLAG_ARGUMENT        (1<<19) ///< set if option is an argument to another option
>  //FIXME think about enc-audio, ... style flags
>  
>      /**
> @@ -386,6 +387,13 @@ typedef struct AVOptionRanges {
>   */
>  int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);
>  
> +/**
> + * Show the obj arguments.
> + *
> + * @param av_log_obj log context to use for showing the options
> + */
> +int av_arg_show(void *obj, void *av_log_obj);
> +
>  /**
>   * Set the values of all AVOption fields to their default values.
>   *

1. Changes to the tools and the libraries should be in separate patches.
E.g. judging by the commit message one would not think that this would
change libavutil by adding a public function; but it does!
2. I don't really get what the documentation of AV_OPT_FLAG_ARGUMENT
means. It seems to be some magic parameter which allows one to
request/reject AVOptions in av_opt_show2().
3. av_arg_show(obj, av_log_obj) is equivalent to av_opt_show2(obj,
av_log_obj, AV_OPT_FLAG_ARGUMENT, 0).

- Andreas