Re: [PATCH 04/16] refactor skip_prefix to return a boolean

[Eric Sunshine <sunshine@sunshineco.com>]

On Thu, Jun 19, 2014 at 10:08 PM, Jeff King <peff@peff.net> wrote:
> On Thu, Jun 19, 2014 at 09:59:39PM -0400, Eric Sunshine wrote:
>
>> > diff --git a/git-compat-util.h b/git-compat-util.h
>> > index b6f03b3..556c839 100644
>> > --- a/git-compat-util.h
>> > +++ b/git-compat-util.h
>> > @@ -349,13 +349,31 @@ extern void set_die_is_recursing_routine(int (*routine)(void));
>> >  extern int starts_with(const char *str, const char *prefix);
>> >  extern int ends_with(const char *str, const char *suffix);
>> >
>> > -static inline const char *skip_prefix(const char *str, const char *prefix)
>> > +/*
>> > + * If "str" begins with "prefix", return 1. If out is non-NULL,
>> > + * it it set to str + strlen(prefix) (i.e., the prefix is skipped).
>>
>> The documentation claims that 'out' can be NULL, however, the code
>> does not respect this. NULL 'out' seems rather pointless (unless you
>> want an alias for starts_with()), so presumably the documentation is
>> incorrect.
>
> Thanks for catching. My original version (before I sent to the list) did
> allow for a conditional NULL out, but I realized there was exactly one
> caller who wanted this, and that they would be better off using
> starts_with. I added patch 3 ("avoid using skip_prefix as a boolean")
> and stripped the conditional from skip_prefix, but forgot to update the
> comment.
>
> I think we'd just want to squash the patch below (I also took the
> opportunity to fix a typo and clarify the text a bit):
>
> diff --git a/git-compat-util.h b/git-compat-util.h
> index 556c839..1187e1a 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -350,8 +350,9 @@ extern int starts_with(const char *str, const char *prefix);
>  extern int ends_with(const char *str, const char *suffix);
>
>  /*
> - * If "str" begins with "prefix", return 1. If out is non-NULL,
> - * it it set to str + strlen(prefix) (i.e., the prefix is skipped).
> + * If the string "str" begins with the string found in "prefix", return 1.
> + * The "out" parameter is set to "str + strlen(prefix)" (i.e., to the point in
> + * the string right after the prefix).
>   *
>   * Otherwise, returns 0 and out is left untouched.

For consistency with the preceding paragraph:

    Otherwise, return 0 and leave "out" untouched.

>   *
>
> -Peff