[PATCH] upload-pack: use buffered I/O to talk to rev-list

From: "René Scharfe" <l.s.r@web.de>
To: Git Mailing List <git@vger.kernel.org>
Cc: Junio C Hamano <gitster@pobox.com>
Subject: [PATCH] upload-pack: use buffered I/O to talk to rev-list
Date: Sun, 2 Aug 2020 16:38:43 +0200	[thread overview]
Message-ID: <6722ade6-971e-7ecc-e8f0-7f595ca0b0ff@web.de> (raw)

Like f0bca72dc77 (send-pack: use buffered I/O to talk to pack-objects,
2016-06-08), significantly reduce the number of system calls and
simplify the code for sending object IDs to rev-list by using stdio's
buffering and handling errors after the loops.

Signed-off-by: René Scharfe <l.s.r@web.de>
---
 upload-pack.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/upload-pack.c b/upload-pack.c
index 86737410709..9f616c2c6a6 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -595,10 +595,9 @@ static int do_reachable_revlist(struct child_process *cmd,
 	static const char *argv[] = {
 		"rev-list", "--stdin", NULL,
 	};
+	FILE *cmd_in;
 	struct object *o;
-	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
 	int i;
-	const unsigned hexsz = the_hash_algo->hexsz;

 	cmd->argv = argv;
 	cmd->git_cmd = 1;
@@ -616,8 +615,8 @@ static int do_reachable_revlist(struct child_process *cmd,
 	if (start_command(cmd))
 		goto error;

-	namebuf[0] = '^';
-	namebuf[hexsz + 1] = '\n';
+	cmd_in = xfdopen(cmd->in, "w");
+
 	for (i = get_max_object_index(); 0 < i; ) {
 		o = get_indexed_object(--i);
 		if (!o)
@@ -626,11 +625,8 @@ static int do_reachable_revlist(struct child_process *cmd,
 			o->flags &= ~TMP_MARK;
 		if (!is_our_ref(o, allow_uor))
 			continue;
-		memcpy(namebuf + 1, oid_to_hex(&o->oid), hexsz);
-		if (write_in_full(cmd->in, namebuf, hexsz + 2) < 0)
-			goto error;
+		fprintf(cmd_in, "^%s\n", oid_to_hex(&o->oid));
 	}
-	namebuf[hexsz] = '\n';
 	for (i = 0; i < src->nr; i++) {
 		o = src->objects[i].item;
 		if (is_our_ref(o, allow_uor)) {
@@ -640,12 +636,11 @@ static int do_reachable_revlist(struct child_process *cmd,
 		}
 		if (reachable && o->type == OBJ_COMMIT)
 			o->flags |= TMP_MARK;
-		memcpy(namebuf, oid_to_hex(&o->oid), hexsz);
-		if (write_in_full(cmd->in, namebuf, hexsz + 1) < 0)
-			goto error;
+		fprintf(cmd_in, "%s\n", oid_to_hex(&o->oid));
 	}
-	close(cmd->in);
 	cmd->in = -1;
+	if (fclose(cmd_in))
+		goto error;
 	sigchain_pop(SIGPIPE);

 	return 0;
@@ -653,8 +648,6 @@ static int do_reachable_revlist(struct child_process *cmd,
 error:
 	sigchain_pop(SIGPIPE);

-	if (cmd->in >= 0)
-		close(cmd->in);
 	if (cmd->out >= 0)
 		close(cmd->out);
 	return -1;
--
2.28.0
