Re: [PATCH v3 13/15] ref-filter: introduce remote_ref_atom_parser()

[Eric Sunshine <sunshine@sunshineco.com>]

On Tue, Jan 5, 2016 at 3:03 AM, Karthik Nayak <karthik.188@gmail.com> wrote:
> Introduce remote_ref_atom_parser() which will parse the '%(upstream)'
> and '%(push)' atoms and store information into the 'used_atom'
> structure based on the modifiers used along with the corresponding
> atom.
>
> Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
> Helped-by: Eric Sunshine <sunshine@sunshineco.com>
> Signed-off-by: Karthik Nayak <Karthik.188@gmail.com>
> ---
> diff --git a/ref-filter.c b/ref-filter.c
> @@ -841,6 +863,43 @@ static inline char *copy_advance(char *dst, const char *src)
> +static void fill_remote_ref_details(struct used_atom *atom, const char *refname,
> +                                   struct branch *branch, const char **s)
> +{
> +       int num_ours, num_theirs;
> +       if (atom->u.remote_ref == RR_SHORTEN)
> +               *s = shorten_unambiguous_ref(refname, warn_ambiguous_refs);
> +       else if (atom->u.remote_ref == RR_TRACK) {
> +               if (stat_tracking_info(branch, &num_ours,
> +                                      &num_theirs, NULL))
> +                       return;
> +
> +               if (!num_ours && !num_theirs)
> +                       *s = "";
> +               else if (!num_ours)
> +                       *s = xstrfmt("[behind %d]", num_theirs);
> +               else if (!num_theirs)
> +                       *s = xstrfmt("[ahead %d]", num_ours);
> +               else
> +                       *s = xstrfmt("[ahead %d, behind %d]",
> +                                    num_ours, num_theirs);
> +       } else if (atom->u.remote_ref == RR_TRACKSHORT) {
> +               if (stat_tracking_info(branch, &num_ours,
> +                                      &num_theirs, NULL))
> +                       return;
> +
> +               if (!num_ours && !num_theirs)
> +                       *s = "=";
> +               else if (!num_ours)
> +                       *s = "<";
> +               else if (!num_theirs)
> +                       *s = ">";
> +               else
> +                       *s = "<>";
> +       } else if (atom->u.remote_ref == RR_NORMAL)
> +               *s = refname;

I think I mentioned this in a previous review: If the code falls past
this final 'else if' for some reason (programmer error), then *s won't
get assigned at all, which is probably undesirable. To protect against
such a case, you might want either to add a final 'else':

    else
        die("BUG: ...");

or just consider RR_NORMAL the catchall case, and turn the final 'else
if' into a plain 'else':

    else /* RR_NORMAL */
        *s = refname;

> +}
> @@ -894,6 +953,8 @@ static void populate_value(struct ref_array_item *ref)
>                         refname = branch_get_upstream(branch, NULL);
>                         if (!refname)
>                                 continue;
> +                       fill_remote_ref_details(atom, refname, branch, &v->s);
> +                       continue;

There are now two 'continue' statements very close together here. Have
you considered this instead?

    if (refname)
        fill_remote_ref_details(...);
    continue;

It might make the code a bit more straightforward. (Genuine question;
I don't feel too strongly about it.)

>                 } else if (starts_with(name, "push")) {
>                         const char *branch_name;
>                         if (!skip_prefix(ref->refname, "refs/heads/",
> @@ -904,6 +965,8 @@ static void populate_value(struct ref_array_item *ref)
>                         refname = branch_get_push(branch, NULL);
>                         if (!refname)
>                                 continue;
> +                       fill_remote_ref_details(atom, refname, branch, &v->s);
> +                       continue;

Ditto.

>                 } else if (starts_with(name, "color:")) {
>                         v->s = atom->u.color;
>                         continue;