Re: [WIP/PATCH v4 1/8] for-each-ref: extract helper functions out of grab_single_ref()

> Extract two helper functions out of grab_single_ref(). Firstly,
> new_refinfo() which is used to allocate memory for a new refinfo
> structure and copy the objectname, refname and flag to it.
> Secondly, match_name_as_path() which when given an array of patterns
> and the refname checks if the refname matches any of the patterns
> given while the pattern is a pathname, also while supporting wild
> characters.
>
> This is a preperatory patch for restructuring 'for-each-ref' and
> eventually moving most of it to 'ref-filter' to provide the
> functionality to similar commands via public API's.
>
> Helped-by: Junio C Hamano <gitster@pobox.com>
> Mentored-by: Christian Couder <christian.couder@gmail.com>
> Mentored-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
> ---
> diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
> index 83f9cf9..b33e2de 100644
> --- a/builtin/for-each-ref.c
> +++ b/builtin/for-each-ref.c
> @@ -837,6 +837,43 @@ struct grab_ref_cbdata {
>  };
>
>  /*
> + * Given a refname, return 1 if the refname matches with one of the patterns
> + * while the pattern is a pathname like 'refs/tags' or 'refs/heads/master'
> + * and so on, else return 0. Supports use of wild characters.
> + */
> +static int match_name_as_path(const char **pattern, const char *refname)
> +{
> +       int namelen = strlen(refname);
> +       for (; *pattern; pattern++) {
> +               const char *p = *pattern;
> +               int plen = strlen(p);
> +
> +               if ((plen <= namelen) &&
> +                   !strncmp(refname, p, plen) &&
> +                   (refname[plen] == '\0' ||
> +                    refname[plen] == '/' ||
> +                    p[plen-1] == '/'))
> +                       return 1;
> +               if (!wildmatch(p, refname, WM_PATHNAME, NULL))
> +                       return 1;
> +       }
> +       return 0;
> +}
> +
> +/* Allocate space for a new refinfo and copy the objectname and flag to it */
> +static struct refinfo *new_refinfo(const char *refname,
> +                                  const unsigned char *objectname,
> +                                  int flag)
> +{
> +       struct refinfo *ref = xcalloc(1, sizeof(struct refinfo));
> +       ref->refname = xstrdup(refname);
> +       hashcpy(ref->objectname, objectname);
> +       ref->flag = flag;
> +
> +       return ref;
> +}
> +
> +/*
>   * A call-back given to for_each_ref().  Filter refs and keep them for
>   * later object processing.
>   */
> @@ -851,40 +888,16 @@ static int grab_single_ref(const char *refname, const unsigned char *sha1, int f
>                   return 0;
>         }
>
> -       if (*cb->grab_pattern) {
> -               const char **pattern;
> -               int namelen = strlen(refname);
> -               for (pattern = cb->grab_pattern; *pattern; pattern++) {
> -                       const char *p = *pattern;
> -                       int plen = strlen(p);
> -
> -                       if ((plen <= namelen) &&
> -                           !strncmp(refname, p, plen) &&
> -                           (refname[plen] == '\0' ||
> -                            refname[plen] == '/' ||
> -                            p[plen-1] == '/'))
> -                               break;
> -                       if (!wildmatch(p, refname, WM_PATHNAME, NULL))
> -                               break;
> -               }
> -               if (!*pattern)
> -                       return 0;
> -       }
> +       if (*cb->grab_pattern && !match_name_as_path(cb->grab_pattern, refname))
> +               return 0;
>
> -       /*
> -        * We do not open the object yet; sort may only need refname
> -        * to do its job and the resulting list may yet to be pruned
> -        * by maxcount logic.
> -        */

> -       ref = xcalloc(1, sizeof(*ref));
> -       ref->refname = xstrdup(refname);
> -       hashcpy(ref->objectname, sha1);
> -       ref->flag = flag;
> +       ref = new_refinfo(refname, sha1, flag);
>
>         cnt = cb->grab_cnt;
>         REALLOC_ARRAY(cb->grab_array, cnt + 1);
>         cb->grab_array[cnt++] = ref;
>         cb->grab_cnt = cnt;
> +