grep: print context hunk marks between files

Print a hunk mark before matches from a new file are shown, in addition
to the current behaviour of printing them if lines have been skipped.

The result is easier to read, as (presumably unrelated) matches from
different files are separated by a hunk mark.  GNU grep does the same.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/grep.c b/grep.c
index 6ee80f7fd9..4bca759b67 100644
--- a/grep.c
+++ b/grep.c
@@ -491,7 +491,12 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
 	int rest = eol - bol;
 
 	if (opt->pre_context || opt->post_context) {
-		if (opt->last_shown && lno > opt->last_shown + 1)
+		if (opt->last_shown == 0) {
+			if (opt->show_hunk_mark)
+				fputs("--\n", stdout);
+			else
+				opt->show_hunk_mark = 1;
+		} else if (lno > opt->last_shown + 1)
 			fputs("--\n", stdout);
 	}
 	opt->last_shown = lno;