From 24b75faf0da7a025a192ab4c65cb1f1d6dc6b7f6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Scharfe?= <l.s.r@web.de>
Date: Wed, 12 Aug 2020 18:52:49 +0200
Subject: connected: use buffered I/O to talk to rev-list

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.

Take care to handle errors immediately to get the correct error code,
and to flush the buffer explicitly before closing the stream in order to
catch any write errors for these last bytes.

Helped-by: Chris Torek <chris.torek@gmail.com>
Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/connected.c b/connected.c
index 937b4ba..eb782f3 100644
--- a/connected.c
+++ b/connected.c
@@ -22,14 +22,13 @@ int check_connected(oid_iterate_fn fn, void *cb_data,
 		    struct check_connected_options *opt)
 {
 	struct child_process rev_list = CHILD_PROCESS_INIT;
+	FILE *rev_list_in;
 	struct check_connected_options defaults = CHECK_CONNECTED_INIT;
-	char commit[GIT_MAX_HEXSZ + 1];
 	struct object_id oid;
 	int err = 0;
 	struct packed_git *new_pack = NULL;
 	struct transport *transport;
 	size_t base_len;
-	const unsigned hexsz = the_hash_algo->hexsz;
 
 	if (!opt)
 		opt = &defaults;
@@ -122,7 +121,8 @@ no_promisor_pack_found:
 
 	sigchain_push(SIGPIPE, SIG_IGN);
 
-	commit[hexsz] = '\n';
+	rev_list_in = xfdopen(rev_list.in, "w");
+
 	do {
 		/*
 		 * If index-pack already checked that:
@@ -135,16 +135,17 @@ no_promisor_pack_found:
 		if (new_pack && find_pack_entry_one(oid.hash, new_pack))
 			continue;
 
-		memcpy(commit, oid_to_hex(&oid), hexsz);
-		if (write_in_full(rev_list.in, commit, hexsz + 1) < 0) {
-			if (errno != EPIPE && errno != EINVAL)
-				error_errno(_("failed write to rev-list"));
-			err = -1;
+		if (fprintf(rev_list_in, "%s\n", oid_to_hex(&oid)) < 0)
 			break;
-		}
 	} while (!fn(cb_data, &oid));
 
-	if (close(rev_list.in))
+	if (ferror(rev_list_in) || fflush(rev_list_in)) {
+		if (errno != EPIPE && errno != EINVAL)
+			error_errno(_("failed write to rev-list"));
+		err = -1;
+	}
+
+	if (fclose(rev_list_in))
 		err = error_errno(_("failed to close rev-list's stdin"));
 
 	sigchain_pop(SIGPIPE);
-- 
cgit v0.10.2-6-g49f6