From: René Scharfe Date: Thu, 14 May 2026 18:40:56 GMT Subject: [PATCH] trailer: change strbuf in-place in unfold_value() Message-ID: <9629b0c1-b28f-4cd2-8d59-67d909ca9052@web.de> Avoid an allocation by doing s/\n\s*/ /g (replacing NL and any following whitespace with a SP) right in the strbuf instead of copying the result to a temporary one and swapping them in the end. We can safely do that because the replacement is never longer than the original string. Signed-off-by: René Scharfe --- Formatted with --function-context for easier review. Inspired by https://lore.kernel.org/git/20260513185408.GA147423@coredump.intra.peff.net/ trailer.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/trailer.c b/trailer.c index 470f86a4a2..b89fa12fe7 100644 --- a/trailer.c +++ b/trailer.c @@ -988,29 +988,25 @@ static int ends_with_blank_line(const char *buf, size_t len) static void unfold_value(struct strbuf *val) { - struct strbuf out = STRBUF_INIT; size_t i; + size_t pos = 0; - strbuf_grow(&out, val->len); i = 0; while (i < val->len) { char c = val->buf[i++]; if (c == '\n') { /* Collapse continuation down to a single space. */ while (i < val->len && isspace(val->buf[i])) i++; - strbuf_addch(&out, ' '); - } else { - strbuf_addch(&out, c); + val->buf[pos++] = ' '; + } else if (pos != i) { + val->buf[pos++] = c; } } + strbuf_setlen(val, pos); /* Empty lines may have left us with whitespace cruft at the edges */ - strbuf_trim(&out); - - /* output goes back to val as if we modified it in-place */ - strbuf_swap(&out, val); - strbuf_release(&out); + strbuf_trim(val); } static struct trailer_block *trailer_block_new(void) -- 2.54.0