Re: [PATCH] general style: replaces memcmp() with proper starts_with()

From: Quint Guvernator <quintus.public@gmail.com>
Date: Mar 13, 2014, 03:33 UTC
Message-ID: <CALs4jVHTBH3wTAQsv8+jb15Do1_oy0pcThsDL8ssE7fgrx5NxA@mail.gmail.com>
In-Reply-To: <xmqqd2hrjb4d.fsf@gitster.dls.corp.google.com>

>From what I can gather, there seems to be opposition to specific

pieces of this patch.

The following area is clearly the most controversial:

Show 12 quoted lines

>  static inline int standard_header_field(const char *field, size_t len)
>  {
> -    return ((len == 4 && !memcmp(field, "tree ", 5)) ||
> -            (len == 6 && !memcmp(field, "parent ", 7)) ||
> -            (len == 6 && !memcmp(field, "author ", 7)) ||
> -            (len == 9 && !memcmp(field, "committer ", 10)) ||
> -            (len == 8 && !memcmp(field, "encoding ", 9)));
> +    return ((len == 4 && starts_with(field, "tree ")) ||
> +            (len == 6 && starts_with(field, "parent ")) ||
> +            (len == 6 && starts_with(field, "author ")) ||
> +            (len == 9 && starts_with(field, "committer ")) ||
> +            (len == 8 && starts_with(field, "encoding ")));

I am happy to submit a version of this patch excluding this section (and/or others), but it seems I've stumbled into a more fundamental conversation about the place for helper functions in general (and about refactoring skip_prefix()). I am working on this particular change as a microproject, #14 on the list [1], and am not as familiar with the conventions of the Git codebase as many of you on this list are.

Junio said:

> The result after the conversion, however, still have the same magic
> numbers, but one less of them each.  Doesn't it make it harder to
> later spot the patterns to come up with a better abstraction that
> does not rely on the magic number?

It is _not_ my goal to make the code harder to maintain down the road. So, at this point, which hunks (if any) are worth patching?

Quint

[1]: http://git.github.io/SoC-2014-Microprojects.html