Re: [PATCH 06/28] qemu-img: create: refresh options/--help

["Daniel P. Berrangé" <berrange@redhat.com>]

On Thu, Feb 22, 2024 at 12:15:47AM +0300, Michael Tokarev wrote:
> Create helper function cmd_help() to display command-specific
> help text, and use it to print --help for 'create' subcommand.
> 
> Add missing long options (eg --format) in img_create().
> 
> Remove usage of missing_argument()/unrecognized_option() in
> img_create().
> 
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
>  qemu-img.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 60 insertions(+), 8 deletions(-)
> 
> diff --git a/qemu-img.c b/qemu-img.c
> index 38ac0f1845..7e4c993b9c 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -132,6 +132,31 @@ void unrecognized_option(const char *option)
>      error_exit("qemu-img", "unrecognized option '%s'", option);
>  }
>  
> +/*
> + * Print --help output for a command and exit.
> + * syntax and description are multi-line with trailing EOL
> + * (to allow easy extending of the text)
> + * syntax has each subsequent line indented by 8 chars.
> + * desrciption is indented by 2 chars for argument on each own line,
> + * and with 5 chars for argument description (like -h arg below).
> + */
> +static G_NORETURN
> +void cmd_help(const img_cmd_t *ccmd,
> +              const char *syntax, const char *arguments)
> +{
> +    printf(
> +"Usage:\n"
> +"  %s %s %s"

For the global help there's an extra '\n' after 'Usage'. It would be
good go be consistent in this between global and per-command help.

$ ./build/qemu-img --help
qemu-img version 8.2.50 (v8.2.0-1677-g81b20f4b55)
Copyright (c) 2003-2023 Fabrice Bellard and the QEMU Project developers
QEMU disk image utility.  Usage:

  qemu-img [standard options] COMMAND [--help | command options]
...snip...

vs

$ ./build/qemu-img info --help
Display information about image.  Usage:
  qemu-img info [-f FMT | --image-opts] [-b] [-U] [--object OBJDEF]
        [--output human|json] FILENAME
...snip...


I wonder if we should repeat '[standard options]' for the
per-command help too ?


> +"\n"
> +"Arguments:\n"

In the global help you called it 'Standard options', so for
consistency lets use 'Options:' here too.

> +"  -h, --help\n"
> +"     print this help and exit\n"
> +"%s\n",
> +           "qemu-img", ccmd->name,
> +           syntax, arguments);
> +    exit(EXIT_SUCCESS);
> +}
> +
>  /* Please keep in synch with docs/tools/qemu-img.rst */
>  static G_NORETURN
>  void help(void)
> @@ -530,23 +555,48 @@ static int img_create(const img_cmd_t *ccmd, int argc, char **argv)
>      for(;;) {
>          static const struct option long_options[] = {
>              {"help", no_argument, 0, 'h'},
> +            {"quiet", no_argument, 0, 'q'},
>              {"object", required_argument, 0, OPTION_OBJECT},
> +            {"format", required_argument, 0, 'f'},
> +            {"backing", required_argument, 0, 'b'},
> +            {"backing-format", required_argument, 0, 'F'},
> +            {"backing-unsafe", no_argument, 0, 'u'},
> +            {"options", required_argument, 0, 'o'},
>              {0, 0, 0, 0}
>          };
> -        c = getopt_long(argc, argv, ":F:b:f:ho:qu",
> +        c = getopt_long(argc, argv, "F:b:f:ho:qu",
>                          long_options, NULL);
>          if (c == -1) {
>              break;
>          }
>          switch(c) {
> -        case ':':
> -            missing_argument(argv[optind - 1]);
> -            break;
> -        case '?':
> -            unrecognized_option(argv[optind - 1]);
> -            break;
>          case 'h':
> -            help();
> +            cmd_help(ccmd,
> +"[-f FMT] [-o FMT_OPTS] [-b BACKING_FILENAME [-F BACKING_FMT]]\n"
> +"        [--object OBJDEF] [-u] FILENAME [SIZE[bkKMGTPE]]\n"
> +,
> +"  -q, --quiet\n"
> +"     quiet operations\n"
> +"  -f, --format FMT\n"
> +"     specifies format of the new image, default is raw\n"
> +"  -o, --options FMT_OPTS\n"
> +"     format-specific options ('-o list' for list)\n"
> +"  -b, --backing BACKING_FILENAME\n"
> +"     stack new image on top of BACKING_FILENAME\n"
> +"     (for formats which support stacking)\n"
> +"  -F, --backing-format BACKING_FMT\n"
> +"     specify format of BACKING_FILENAME\n"
> +"  -u, --backing-unsafe\n"
> +"     do not fail if BACKING_FMT can not be read\n"
> +"  --object OBJDEF\n"
> +"     QEMU user-creatable object (eg encryption key)\n"
> +"  FILENAME\n"
> +"     image file to create.  It will be overridden if exists\n"
> +"  SIZE\n"
> +"     image size with optional suffix (multiplies in 1024)\n"
> +"     SIZE is required unless BACKING_IMG is specified,\n"
> +"     in which case it will be the same as size of BACKING_IMG\n"
> +);
>              break;
>          case 'F':
>              base_fmt = optarg;
> @@ -571,6 +621,8 @@ static int img_create(const img_cmd_t *ccmd, int argc, char **argv)
>          case OPTION_OBJECT:
>              user_creatable_process_cmdline(optarg);
>              break;
> +        default:
> +            tryhelp(argv[0]);
>          }
>      }
>  
> -- 
> 2.39.2
> 
> 

With regards,
Daniel
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