Re: [RFC PATCH 1/3] xdiff-interface: make xdl_blankline() available

[Stefan Beller <sbeller@google.com>]

On Mon, Sep 24, 2018 at 3:06 AM Phillip Wood <phillip.wood@talktalk.net> wrote:
>
> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>
> This will be used by the move detection code.
>
> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
> ---
>  xdiff-interface.c | 5 +++++
>  xdiff-interface.h | 5 +++++
>  2 files changed, 10 insertions(+)
>
> diff --git a/xdiff-interface.c b/xdiff-interface.c
> index 9315bc0ede..eceabfa72d 100644
> --- a/xdiff-interface.c
> +++ b/xdiff-interface.c
> @@ -308,6 +308,11 @@ int xdiff_compare_lines(const char *l1, long s1,
>         return xdl_recmatch(l1, s1, l2, s2, flags);
>  }
>
> +int xdiff_is_blankline(const char *l1, long s1, long flags)
> +{
> +       return xdl_blankline(l1, s1, flags);
> +}
> +
>  int git_xmerge_style = -1;
>
>  int git_xmerge_config(const char *var, const char *value, void *cb)
> diff --git a/xdiff-interface.h b/xdiff-interface.h
> index 135fc05d72..d0008b016f 100644
> --- a/xdiff-interface.h
> +++ b/xdiff-interface.h
> @@ -45,4 +45,9 @@ extern int xdiff_compare_lines(const char *l1, long s1,
>   */
>  extern unsigned long xdiff_hash_string(const char *s, size_t len, long flags);
>
> +/*
> + * Returns 1 if the line is blank, taking XDF_WHITESPACE_FLAGS into account

presumably in the flags field.

> + */
> +extern int xdiff_is_blankline(const char *s, long len, long flags);

We also have
    int ws_blank_line(const char *, int, int)
that looks very similar, but works slightly differently.
grep.c has
    static int is_empty_line(const char *bol, const char *eol)
    {
       while (bol < eol && isspace(*bol))
       bol++;
       return bol == eol;
    }

pretty.c also has a is_blank_line() (and some stale comment in
that file refers to it as is_empty_line, 77356122443
(pretty: make the skip_blank_lines() function public,
2016-06-22)

Would we be able to unify all these down to one or two
functions? (Maybe all can use the new xdiff function?)
It seems as if we're reinventing the wheel a couple times
in our code base.

Stefan