Re: [PATCH] attr: expose validity check for attribute names

> Export attr_name_valid() function, and a helper function that
> returns the message to be given when a given <name, len> pair
> is not a good name for an attribute.
>
> We could later update the message to exactly spell out what the
> rules for a good attribute name are, etc.
>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
>  * And then finally the error message one.  I didn't change
>    the message itself to spell out the rules here, though.
>
>  attr.c | 39 +++++++++++++++++++++++++--------------
>  attr.h |  3 +++
>  2 files changed, 28 insertions(+), 14 deletions(-)
>
> diff --git a/attr.c b/attr.c
> index 7f20e21..8f54871 100644
> --- a/attr.c
> +++ b/attr.c
> @@ -59,23 +59,38 @@ static unsigned hash_name(const char *name, int namelen)
>         return val;
>  }
>
> -static int invalid_attr_name(const char *name, int namelen)
> +int attr_name_valid(const char *name, size_t namelen)

>  {
>         /*
>          * Attribute name cannot begin with '-' and must consist of
>          * characters from [-A-Za-z0-9_.].
>          */
>         if (namelen <= 0 || *name == '-')
> -               return -1;
> +               return 0;
>         while (namelen--) {
>                 char ch = *name++;
>                 if (! (ch == '-' || ch == '.' || ch == '_' ||
>                        ('0' <= ch && ch <= '9') ||
>                        ('a' <= ch && ch <= 'z') ||
>                        ('A' <= ch && ch <= 'Z')) )
> -                       return -1;
> +                       return 0;
>         }
> -       return 0;
> +       return -1;
> +}
> +
> +void invalid_attr_name_message(struct strbuf *err, const char *name, int len)
> +{
> +       strbuf_addf(err, _("%.*s is not a valid attribute name"),
> +                   len, name);
> +}
> +
> +static void report_invalid_attr(const char *name, size_t len,
> +                               const char *src, int lineno)
> +{
> +       struct strbuf err = STRBUF_INIT;
> +       invalid_attr_name_message(&err, name, len);
> +       fprintf(stderr, "%s: %s:%d\n", err.buf, src, lineno);
> +       strbuf_release(&err);
>  }
>
>  struct git_attr *git_attr_counted(const char *name, size_t len)
> @@ -90,7 +105,7 @@ struct git_attr *git_attr_counted(const char *name, size_t len)
>                         return a;
>         }
>
> -       if (invalid_attr_name(name, len))
> +       if (!attr_name_valid(name, len))
>                 return NULL;
>
>         FLEX_ALLOC_MEM(a, name, name, len);
> @@ -176,17 +191,15 @@ static const char *parse_attr(const char *src, int lineno, const char *cp,
>                         cp++;
>                         len--;
>                 }
> -               if (invalid_attr_name(cp, len)) {
> -                       fprintf(stderr,
> -                               "%.*s is not a valid attribute name: %s:%d\n",
> -                               len, cp, src, lineno);
> +               if (!attr_name_valid(cp, len)) {
> +                       report_invalid_attr(cp, len, src, lineno);
>                         return NULL;
>                 }
>         } else {
>                 /*
>                  * As this function is always called twice, once with
>                  * e == NULL in the first pass and then e != NULL in
> -                * the second pass, no need for invalid_attr_name()
> +                * the second pass, no need for attr_name_valid()
>                  * check here.
>                  */
>                 if (*cp == '-' || *cp == '!') {
> @@ -229,10 +242,8 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
>                 name += strlen(ATTRIBUTE_MACRO_PREFIX);
>                 name += strspn(name, blank);
>                 namelen = strcspn(name, blank);
> -               if (invalid_attr_name(name, namelen)) {
> -                       fprintf(stderr,
> -                               "%.*s is not a valid attribute name: %s:%d\n",
> -                               namelen, name, src, lineno);
> +               if (!attr_name_valid(name, namelen)) {
> +                       report_invalid_attr(name, namelen, src, lineno);
>                         return NULL;
>                 }
>         }
> diff --git a/attr.h b/attr.h
> index 78d6d5a..fc72030 100644
> --- a/attr.h
> +++ b/attr.h
> @@ -13,6 +13,9 @@ extern struct git_attr *git_attr(const char *);
>  /* The same, but with counted string */
>  extern struct git_attr *git_attr_counted(const char *, size_t);
>
> +extern int attr_name_valid(const char *name, size_t namelen);

> +
>  /* Internal use */
>  extern const char git_attr__true[];
>  extern const char git_attr__false[];
> --
> 2.8.2-759-geb611ab
>