Subject: Re: [PATCH 05/19] diff.c: emit_line_0 can handle no color setting

From: Jonathan Tan <[email-masked]>
Date: Mon, 15 May 2017 11:31:26 -0700

On 05/13/2017 09:01 PM, Stefan Beller wrote:
> In a later patch, I want to propose an option to detect&color
> moved lines in a diff, which cannot be done in a one-pass over
> the diff. Instead we need to go over the whole diff twice,
> because we cannot detect the first line of the two corresponding
> lines (+ and -) that got moved.
>
> So to prepare the diff machinery for two pass algorithms
> (i.e. buffer it all up and then operate on the result),
> move all emissions to places, such that the only emitting
> function is emit_line_0.
>
> In later patches we may pass lines that are not colored to
> the central function emit_line_0, so we
> need to emit the color only when it is non-NULL.

The diff below seems to just make emit_line_0 allow NULL for set and 
reset, unlike what the commit message above describes. (And is that 
necessary? Couldn't the caller just pass "" if they don't want any 
setting and/or resetting?)

>
> Signed-off-by: Stefan Beller <[email-masked]>
> ---
>  diff.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/diff.c b/diff.c
> index 381b572d76..48f0fb98dc 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -532,11 +532,13 @@ static void emit_line_0(struct diff_options *o, const char *set, const char *res
>  		len--;
>
>  	if (len || sign) {
> -		fputs(set, file);
> +		if (set)
> +			fputs(set, file);
>  		if (sign)
>  			fputc(sign, file);
>  		fwrite(line, len, 1, file);
> -		fputs(reset, file);
> +		if (reset)
> +			fputs(reset, file);
>  	}
>  	if (has_trailing_carriage_return)
>  		fputc('\r', file);
>