"Johannes Schindelin via GitGitGadget" <gitgitgadget@xxxxxxxxx>
writes:
> From: Johannes Schindelin <johannes.schindelin@xxxxxx>
>
> When diffing diffs, it can be quite daunting to figure out what the heck
> is going on, as there are nested +/- signs.
>
> Let's make this easier by adding a flag in diff_options that allows
> color-coding the outer diff sign with inverted colors, so that the
> preimage and postimage is colored like the diff it is.
>
> Of course, this really only makes sense when the preimage and postimage
> *are* diffs. So let's not expose this flag via a command-line option for
> now.
>
> This is a feature that was invented by git-tbdiff, and it will be used
> by `git range-diff` in the next commit, by offering it via a new option:
> `--dual-color`.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
> ---
> diff.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++-----------
> diff.h | 1 +
> 2 files changed, 69 insertions(+), 15 deletions(-)
>
> diff --git a/diff.c b/diff.c
> index a94a8214f..e163bc8a3 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -563,14 +563,18 @@ static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
> ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
> }
>
> -static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
> +static void emit_line_0(struct diff_options *o,
> + const char *set, unsigned reverse, const char *reset,
> int first, const char *line, int len)
> {
> int has_trailing_newline, has_trailing_carriage_return;
> int nofirst;
> FILE *file = o->file;
>
> - fputs(diff_line_prefix(o), file);
> + if (first)
> + fputs(diff_line_prefix(o), file);
> + else if (!len)
> + return;
Can you explain this hunk in the log message? I am not sure how the
description in the log message relates to this change. Is the idea
of this change essentially "all the existing callers that aren't
doing the diff-of-diffs send a non-NUL first character, and for them
this change is a no-op. New callers share most of the remainder of
emit_line_0() logic but do not want to show the prefix, so the
support for it is piggy-backing by a special case where first could
be NUL"?
