Re: [PATCH v3] tag: support --sort=<spec>

[Jeff King <peff@peff.net>]

On Tue, Feb 25, 2014 at 07:22:15PM +0700, Nguyễn Thái Ngọc Duy wrote:

> versioncmp() is copied from string/strverscmp.c in glibc commit
> ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
> style. The implementation is under LGPL-2.1 and according to [1] I can
> relicense it to GPLv2.

Cool. I think doing this makes the most sense, as we do not have to
worry about build-time config (and I do not see any particular reason
why we would want to use the system strverscmp on glibc systems).

> +static int parse_opt_sort(const struct option *opt, const char *arg, int unset)
> +{
> +	int *sort = opt->value;
> +	if (*arg == '-') {
> +		*sort = REVERSE_SORT;
> +		arg++;
> +	} else
> +		*sort = STRCMP_SORT;
> +	if (starts_with(arg, "version:")) {
> +		*sort |= VERCMP_SORT;
> +		arg += 8;
> +	} else if (starts_with(arg, "v:")) {
> +		*sort |= VERCMP_SORT;
> +		arg += 2;
> +	}
> +	if (strcmp(arg, "refname"))
> +		die(_("unsupported sort specification %s"), arg);

I found this logic a bit weird, as STRCMP_SORT and VERCMP_SORT are not
mutually exclusive flags, but REVERSE and STRCMP are. I would have
thought REVERSE is the flag, and the other two are selections. Like:

  int flags = 0;

  if (*arg == '-') {
          flags |= REVERSE_SORT;
          arg++;
  }
  if (starts_with(arg, "version:")) {
          *sort = VERCMP_SORT;
          arg += 8;
  } else
          *sort = STRCMP_SORT;

  *sort |= flags;

I think they end up doing the same thing, but maybe I am missing
something.

-Peff