pretty: add support for separator option in %(trailers)

By default trailer lines are terminated by linebreaks ('\n'). By
specifying the new 'separator' option they will instead be separated by
user provided string and have separator semantics rather than terminator
semantics. The separator string can contain the literal formatting codes
%n and %xNN allowing it to be things that are otherwise hard to type
such as %x00, or comma and end-parenthesis which would break parsing.

E.g:
 $ git log --pretty='%(trailers:key=Reviewed-by,valueonly,separator=%x00)'

Signed-off-by: Anders Waldenborg <anders@0x63.nu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/trailer.c b/trailer.c
index d0d9e91631..0c414f2fed 100644
--- a/trailer.c
+++ b/trailer.c
@@ -1129,10 +1129,11 @@ static void format_trailer_info(struct strbuf *out,
 				const struct trailer_info *info,
 				const struct process_trailer_options *opts)
 {
+	size_t origlen = out->len;
 	size_t i;
 
 	/* If we want the whole block untouched, we can take the fast path. */
-	if (!opts->only_trailers && !opts->unfold && !opts->filter) {
+	if (!opts->only_trailers && !opts->unfold && !opts->filter && !opts->separator) {
 		strbuf_add(out, info->trailer_start,
 			   info->trailer_end - info->trailer_start);
 		return;
@@ -1150,16 +1151,26 @@ static void format_trailer_info(struct strbuf *out,
 			if (!opts->filter || opts->filter(&tok, opts->filter_data)) {
 				if (opts->unfold)
 					unfold_value(&val);
+
+				if (opts->separator && out->len != origlen)
+					strbuf_addbuf(out, opts->separator);
 				if (!opts->value_only)
 					strbuf_addf(out, "%s: ", tok.buf);
 				strbuf_addbuf(out, &val);
-				strbuf_addch(out, '\n');
+				if (!opts->separator)
+					strbuf_addch(out, '\n');
 			}
 			strbuf_release(&tok);
 			strbuf_release(&val);
 
 		} else if (!opts->only_trailers) {
+			if (opts->separator && out->len != origlen) {
+				strbuf_addbuf(out, opts->separator);
+			}
 			strbuf_addstr(out, trailer);
+			if (opts->separator) {
+				strbuf_rtrim(out);
+			}
 		}
 	}