[PATCH v6 23/42] receive-pack.c: use a reference transaction for updating the refs

From: Ronnie Sahlberg <sahlberg@google.com>
To: git@vger.kernel.org
Cc: mhagger@alum.mit.edu, Ronnie Sahlberg <sahlberg@google.com>
Subject: [PATCH v6 23/42] receive-pack.c: use a reference transaction for updating the refs
Date: Thu,  1 May 2014 13:37:23 -0700	[thread overview]
Message-ID: <1398976662-6962-24-git-send-email-sahlberg@google.com> (raw)
In-Reply-To: <1398976662-6962-1-git-send-email-sahlberg@google.com>

Wrap all the ref updates inside a transaction to make the update atomic.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 builtin/receive-pack.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index c323081..d580176 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -46,6 +46,8 @@ static void *head_name_to_free;
 static int sent_capabilities;
 static int shallow_update;
 static const char *alt_shallow_file;
+struct strbuf err = STRBUF_INIT;
+struct ref_transaction *transaction;
 
 static enum deny_action parse_deny_action(const char *var, const char *value)
 {
@@ -475,7 +477,6 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 	const char *namespaced_name;
 	unsigned char *old_sha1 = cmd->old_sha1;
 	unsigned char *new_sha1 = cmd->new_sha1;
-	struct ref_lock *lock;
 
 	/* only refs/... are allowed */
 	if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
@@ -580,15 +581,9 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		    update_shallow_ref(cmd, si))
 			return "shallow error";
 
-		lock = lock_any_ref_for_update(namespaced_name, old_sha1,
-					       0, NULL);
-		if (!lock) {
-			rp_error("failed to lock %s", name);
-			return "failed to lock";
-		}
-		if (write_ref_sha1(lock, new_sha1, "push")) {
-			return "failed to write"; /* error() already called */
-		}
+		if (ref_transaction_update(transaction, namespaced_name,
+					   new_sha1, old_sha1, 0, 1))
+			return "failed to update";
 		return NULL; /* good */
 	}
 }
@@ -812,6 +807,7 @@ static void execute_commands(struct command *commands,
 	head_name = head_name_to_free = resolve_refdup("HEAD", sha1, 0, NULL);
 
 	checked_connectivity = 1;
+	transaction = ref_transaction_begin();
 	for (cmd = commands; cmd; cmd = cmd->next) {
 		if (cmd->error_string)
 			continue;
@@ -827,6 +823,10 @@ static void execute_commands(struct command *commands,
 			checked_connectivity = 0;
 		}
 	}
+	if (ref_transaction_commit(transaction, "push", &err))
+		error("%s", err.buf);
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
 
 	if (shallow_update && !checked_connectivity)
 		error("BUG: run 'git fsck' for safety.\n"
-- 
2.0.0.rc1.351.g4d2c8e4
