[PATCH 31/31] refs.c: use the transaction to manage the reflog in rename_refs

[Ronnie Sahlberg <sahlberg@google.com>]

We have a transaction in rename_ref to managing the ref during the rename.
Use this transaction to manage the changes to the reflog too.
This now means that rename_ref is almost completely agnostic about how refs
storage is implemented and should be easier to migrate if/when we allow a
different store for refs, such as a database.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 refs.c | 62 ++++++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 42 insertions(+), 20 deletions(-)

diff --git a/refs.c b/refs.c
index bcce8fe..829c89a 100644
--- a/refs.c
+++ b/refs.c
@@ -2633,6 +2633,24 @@ struct ref_update {
 	const char refname[FLEX_ARRAY];
 };
 
+struct rename_reflog_cb {
+       struct ref_transaction *t;
+       const char *refname;
+};
+
+static int rename_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
+			     const char *email, unsigned long timestamp, int tz,
+			     const char *message, void *cb_data)
+{
+       struct rename_reflog_cb *cb = cb_data;
+
+       transaction_update_reflog(cb->t, cb->refname, nsha1, osha1,
+				 email, timestamp, tz, message, 0,
+				 NULL);
+
+       return 0;
+}
+
 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
 {
 	unsigned char sha1[20];
@@ -2664,40 +2682,44 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 				  get_loose_refs(&ref_cache), NULL, 0))
 		return 1;
 
-	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
-		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
-			oldrefname, strerror(errno));
-
 	if (pack_refs(PACK_REFS_ALL | PACK_REFS_PRUNE))
 		return error("unable to pack refs");
 
 	transaction = transaction_begin();
-	if (!transaction ||
-	    transaction_delete_sha1(transaction, oldrefname, sha1,
+	if (log) {
+		struct rename_reflog_cb cb;
+
+		transaction_update_reflog(transaction, newrefname,
+					  null_sha1, null_sha1, NULL,
+					  0, 0, NULL,
+					  REFLOG_TRUNCATE,
+					  NULL);
+
+		cb.t = transaction;
+		cb.refname = newrefname;
+		for_each_reflog_ent(oldrefname, rename_reflog_ent, &cb);
+
+		transaction_update_reflog(transaction, newrefname,
+					  sha1, sha1,
+					  git_committer_info(0),
+					  0, 0, logmsg,
+					  REFLOG_EMAIL_IS_COMMITTER,
+					  &err);
+	}
+
+	if (transaction_delete_sha1(transaction, oldrefname, sha1,
 				    REF_NODEREF | REF_ISPACKONLY,
 				    1, NULL, &err) ||
 	    transaction_update_sha1(transaction, newrefname, sha1,
-				    NULL, 0, 0, logmsg, &err) ||
+				    NULL, 0, 0, NULL, &err) ||
 	    transaction_commit(transaction, &err)) {
 		transaction_rollback(transaction);
 		error("rename_ref failed: %s", err.buf);
 		strbuf_release(&err);
-		goto rollbacklog;
+		return 1;
 	}
 	transaction_free(transaction);
-
-	if (log && rename_tmp_log(newrefname))
-		goto rollbacklog;
-
 	return 0;
-
- rollbacklog:
-	if (log &&
-	    rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
-		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
-			oldrefname, strerror(errno));
-
-	return 1;
 }
 
 static int close_ref(struct ref_lock *lock)
-- 
2.0.0.rc3.506.g3739a35