[PATCH 3/5] grep: stop modifying buffer in grep_source_1()

From: Jeff King <peff@peff.net>
To: git@vger.kernel.org
Cc: Hamza Mahfooz <someguy@effective-light.com>
Subject: [PATCH 3/5] grep: stop modifying buffer in grep_source_1()
Date: Mon, 20 Sep 2021 23:48:44 -0400	[thread overview]
Message-ID: <YUlWHASpQDJehiZH@coredump.intra.peff.net> (raw)
In-Reply-To: <YUlVZk1xXulAqdef@coredump.intra.peff.net>

We find the end of each matching line of a buffer, and then temporarily
write a NUL to turn it into a regular C string. But we don't need to do
so, because the only thing we do in the interim is pass the line and its
length (via an "eol" pointer) to match_line(). And that function should
only look at the bytes we passed it, whether it has a terminating NUL or
not.

We can drop this temporary write in order to simplify the code and make
it easier to use const buffers in more of grep.c.

Signed-off-by: Jeff King <peff@peff.net>
---
 grep.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/grep.c b/grep.c
index 70af01d1c1..32c4641443 100644
--- a/grep.c
+++ b/grep.c
@@ -1616,7 +1616,7 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 	bol = gs->buf;
 	left = gs->size;
 	while (left) {
-		char *eol, ch;
+		char *eol;
 		int hit;
 		ssize_t cno;
 		ssize_t col = -1, icol = -1;
@@ -1637,14 +1637,11 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
 		    && look_ahead(opt, &left, &lno, &bol))
 			break;
 		eol = end_of_line(bol, &left);
-		ch = *eol;
-		*eol = 0;
 
 		if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 			ctx = GREP_CONTEXT_BODY;
 
 		hit = match_line(opt, bol, eol, &col, &icol, ctx, collect_hits);
-		*eol = ch;
 
 		if (collect_hits)
 			goto next_line;
-- 
2.33.0.1023.gc687d0d3c8

