From: Eric Sunshine <sunshine@sunshineco.com>
Date: Wed, 16 Dec 2015 21:54:41 GMT
Subject: Re: [PATCH v2 07/11] ref-filter: introduce align_atom_parser()
Message-ID: <CAPig+cR=dYnMfaHUYcq_kz8M+C1nCxOX=SN=_6+ep1aWvVCUow@mail.gmail.com>
In-Reply-To: <1450279802-29414-8-git-send-email-Karthik.188@gmail.com>

On Wed, Dec 16, 2015 at 10:29 AM, Karthik Nayak <karthik.188@gmail.com> wrote:
> Introduce align_atom_parser() which will parse an "align" atom and
> store the required alignment position and width in the "use_atom"
> structure for further usage in 'populate_value()'.
>
> Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
> Signed-off-by: Karthik Nayak <Karthik.188@gmail.com>
> ---
> diff --git a/ref-filter.c b/ref-filter.c
> @@ -63,6 +69,49 @@ static void color_atom_parser(struct used_atom *atom)
> +static align_type parse_align_position(const char *s)
> +{
> +       if (!strcmp(s, "right"))
> +               return ALIGN_RIGHT;
> +       else if (!strcmp(s, "middle"))
> +               return ALIGN_MIDDLE;
> +       else if (!strcmp(s, "left"))
> +               return ALIGN_LEFT;
> +       return -1;
> +}
> +
> +static void align_atom_parser(struct used_atom *atom)
> +{
> +       struct align *align = &atom->u.align;
> +       const char *buf = NULL;
> +       struct strbuf **s, **to_free;
> +       int width = -1;
> +
> +       match_atom_name(atom->str, "align", &buf);
> +       if (!buf)
> +               die(_("expected format: %%(align:<width>,<position>)"));
> +       s = to_free = strbuf_split_str_omit_term(buf, ',', 0);
> +
> +       align->position = ALIGN_LEFT;
> +
> +       while (*s) {
> +               int position;
> +
> +               if (!strtoul_ui(s[0]->buf, 10, (unsigned int *)&width))

This casting is pretty ugly. It probably would be cleaner to declare
'width' as 'unsigned int' and initialize it with ~0U than to do this
ugly and potentially dangerous casting. Likewise, below where you
check 'width < 0', you'd check instead for ~0U. However, such a change
should not be part of the current patch, but rather as a separate
preparatory patch.

> +                       ;
> +               else if ((position = parse_align_position(s[0]->buf)) > 0)

Shouldn't this be '>=' rather than '>'?

This likely would have been easier to spot if parse_align_position()
had been factored out in its own patch, as suggested by my v1
review[1], since the caller would have been trivially inspectable
rather than having to keep track of both code movement and changes.

[1]: http://article.gmane.org/gmane.comp.version-control.git/281916

> +                       align->position = position;
> +               else
> +                       die(_("unrecognized %%(align) argument: %s"), s[0]->buf);
> +               s++;
> +       }
> +
> +       if (width < 0)
> +               die(_("positive width expected with the %%(align) atom"));
> +       align->width = width;
> +       strbuf_list_free(to_free);
> +}
> +
>  static struct {
>         const char *name;
>         cmp_type cmp_type;
> @@ -880,35 +924,7 @@ static void populate_value(struct ref_array_item *ref)
>                                 v->s = " ";
>                         continue;
>                 } else if (match_atom_name(name, "align", &valp)) {
> -                       struct align *align = &v->u.align;
> -                       struct strbuf **s, **to_free;
> -                       int width = -1;
> -
> -                       if (!valp)
> -                               die(_("expected format: %%(align:<width>,<position>)"));
> -
> -                       s = to_free = strbuf_split_str_omit_term(valp, ',', 0);
> -
> -                       align->position = ALIGN_LEFT;
> -
> -                       while (*s) {
> -                               if (!strtoul_ui(s[0]->buf, 10, (unsigned int *)&width))
> -                                       ;
> -                               else if (!strcmp(s[0]->buf, "left"))
> -                                       align->position = ALIGN_LEFT;
> -                               else if (!strcmp(s[0]->buf, "right"))
> -                                       align->position = ALIGN_RIGHT;
> -                               else if (!strcmp(s[0]->buf, "middle"))
> -                                       align->position = ALIGN_MIDDLE;
> -                               else
> -                                       die(_("improper format entered align:%s"), s[0]->buf);
> -                               s++;
> -                       }
> -
> -                       if (width < 0)
> -                               die(_("positive width expected with the %%(align) atom"));
> -                       align->width = width;
> -                       strbuf_list_free(to_free);
> +                       v->u.align = atom->u.align;
>                         v->handler = align_atom_handler;
>                         continue;
>                 } else if (!strcmp(name, "end")) {
> --
> 2.6.4