[PATCH] diff: retire sane_truncate_fn

[PATCH] diff: retire sane_truncate_fn

[Junio C Hamano]

Long time ago, 23707811 ("diff: do not chomp hunk-header in the
middle of a character", 2008-01-02) introduced sane_truncate_line()
helper function to trim the "function header" line that is shown at
the end of the hunk header line, in order to avoid chomping it in
the middle of a single UTF-8 character.  It also added a facility to
define a custom callback function to make it possible to extend it
to non UTF-8 encodings.  

During the following 8 1/2 years, nobody found need for this custom
callback facility.

A custom callback function is a wrong design to use here anyway---if
your contents need support for non UTF-8 encoding, you shouldn't
have to write a custom function and recompile Git to plumb it in.  A
better approach would be to extend sane_truncate_line() function and
have a new member in emit_callback to conditionally trigger it.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 diff.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/diff.c b/diff.c
index a628ac3a95..4bdaed8197 100644
--- a/diff.c
+++ b/diff.c
@@ -408,8 +408,6 @@ static struct diff_tempfile {
 	struct tempfile tempfile;
 } diff_temp[2];
 
-typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
-
 struct emit_callback {
 	int color_diff;
 	unsigned ws_rule;
@@ -417,7 +415,6 @@ struct emit_callback {
 	int blank_at_eof_in_postimage;
 	int lno_in_preimage;
 	int lno_in_postimage;
-	sane_truncate_fn truncate;
 	const char **label_path;
 	struct diff_words_data *diff_words;
 	struct diff_options *opt;
@@ -1246,8 +1243,6 @@ static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, u
 	unsigned long allot;
 	size_t l = len;
 
-	if (ecb->truncate)
-		return ecb->truncate(line, len);
 	cp = line;
 	allot = l;
 	while (0 < l) {

Re: [PATCH] diff: retire sane_truncate_fn

[Stefan Beller]

On Thu, Aug 17, 2017 at 10:27 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Long time ago, 23707811 ("diff: do not chomp hunk-header in the
> middle of a character", 2008-01-02) introduced sane_truncate_line()
> helper function to trim the "function header" line that is shown at
> the end of the hunk header line, in order to avoid chomping it in
> the middle of a single UTF-8 character.  It also added a facility to
> define a custom callback function to make it possible to extend it
> to non UTF-8 encodings.
>
> During the following 8 1/2 years, nobody found need for this custom
> callback facility.
>
> A custom callback function is a wrong design to use here anyway---if
> your contents need support for non UTF-8 encoding, you shouldn't
> have to write a custom function and recompile Git to plumb it in.  A
> better approach would be to extend sane_truncate_line() function and
> have a new member in emit_callback to conditionally trigger it.
>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>

This patch is
Reviewed-by: Stefan Beller <sbeller@google.com>

However while strolling around in code nearby, I do
wonder if sane_truncate_line needs to make use
of the return value of utf8_width. But that is not the case
as we're interested in the byte length, not the print length.

Thanks
Stefan