Re: [PATCH v3 08/15] ref-filter: introduce color_atom_parser()

On Wed, Jan 6, 2016 at 2:19 AM, Junio C Hamano [off-list ref] wrote:

Karthik Nayak [off-list ref] writes:

quoted

Introduce color_atom_parser() which will parse a "color" atom and
store its color in the "used_atom" structure for further usage in
populate_value().

Helped-by: Ramsay Jones [off-list ref]
Helped-by: Eric Sunshine [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
 ref-filter.c | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/ref-filter.c b/ref-filter.c
index b54c872..9708d67 100644
--- a/ref-filter.c
+++ b/ref-filter.c

@@ -29,6 +29,9 @@ typedef enum { FIELD_STR, FIELD_ULONG, FIELD_TIME } cmp_type;
 static struct used_atom {
      const char *name;
      cmp_type type;
+     union {
+             char *color;
+     } u;
 } *used_atom;
 static int used_atom_cnt, need_tagged, need_symref;
 static int need_color_reset_at_eol;

@@ -53,6 +56,18 @@ static int match_atom_name(const char *name, const char *atom_name, const char *
      return 1;
 }

+static void color_atom_parser(struct used_atom *atom)
+{
+     if (!match_atom_name(atom->name, "color", (const char **)&atom->u.color))
+             die("BUG: parsing non-'color'");
+     if (!atom->u.color)
+             die(_("expected format: %%(color:<color>)"));
+     /* atom->u.color points to part of atom->name */
+     atom->u.color = xstrdup(atom->u.color);
+     if (color_parse(atom->u.color, atom->u.color) < 0)
+             die(_("invalid color value: %s"), atom->u.color);

Is this calling color_parse() from color.c?

Yes it is!

The function wants the destination to be at least COLOR_MAXLEN, but
I do not see where the piece memory pointed by atom->u.color is
guaranteed to be that long in the new code.  Looking at the code
removed by this patch, it used to correctly use a buffer that is
COLOR_MAXLEN bytes long.  So...

        const char *color_value;

        if (!match_atom_name(atom->name, "color", color_value))
                die("BUG: parsing non-'color'");
        if (!color_value)
                die(_("expected format: %%(color:<color>)"));
        atom->u.color = xmalloc(COLOR_MAXLEN);
        if (color_parse(color_value, atom->u.color) < 0)
                die(_("invalid color value: %s"), color_value);

or even define it in the union, i.e.

        union {
                char color[COLOR_MAXLEN];
        } u;

and then use atom->u.color[] in-place?

I like the in-place suggestion, I wasn't wary of the Minimum length requirement
of the dest in color_parser(). Thanks for bringing it up. Will change.

-- 
Regards,
Karthik Nayak