refs.c: move reflog updates into its own function

write_ref_sha1 tries to update the reflog while updating the ref.
Move these reflog changes out into its own function so that we can do the
same thing if we write a sha1 ref differently, for example by writing a ref
to the packed refs file instead.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 36 insertions, 26 deletions

diff --git a/refs.c b/refs.c
index a7b2db18ac..fe298c5265 100644
--- a/refs.c
+++ b/refs.c
@@ -2885,6 +2885,39 @@ static int is_branch(const char *refname)
 	return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 }
 
+static int write_sha1_update_reflog(struct ref_lock *lock,
+	const unsigned char *sha1, const char *logmsg)
+{
+	if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
+	    (strcmp(lock->ref_name, lock->orig_ref_name) &&
+	     log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
+		return -1;
+	}
+	if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
+		/*
+		 * Special hack: If a branch is updated directly and HEAD
+		 * points to it (may happen on the remote side of a push
+		 * for example) then logically the HEAD reflog should be
+		 * updated too.
+		 * A generic solution implies reverse symref information,
+		 * but finding all symrefs pointing to the given branch
+		 * would be rather costly for this rare event (the direct
+		 * update of a branch) to be worth it.  So let's cheat and
+		 * check with HEAD only which should cover 99% of all usage
+		 * scenarios (even 100% of the default ones).
+		 */
+		unsigned char head_sha1[20];
+		int head_flag;
+		const char *head_ref;
+		head_ref = resolve_ref_unsafe("HEAD", head_sha1,
+					      RESOLVE_REF_READING, &head_flag);
+		if (head_ref && (head_flag & REF_ISSYMREF) &&
+		    !strcmp(head_ref, lock->ref_name))
+			log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
+	}
+	return 0;
+}
+
 /*
  * Writes sha1 into the ref specified by the lock. Makes sure that errno
  * is sane on error.
@@ -2928,34 +2961,10 @@ static int write_ref_sha1(struct ref_lock *lock,
 		return -1;
 	}
 	clear_loose_ref_cache(&ref_cache);
-	if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
-	    (strcmp(lock->ref_name, lock->orig_ref_name) &&
-	     log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
+	if (write_sha1_update_reflog(lock, sha1, logmsg)) {
 		unlock_ref(lock);
 		return -1;
 	}
-	if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
-		/*
-		 * Special hack: If a branch is updated directly and HEAD
-		 * points to it (may happen on the remote side of a push
-		 * for example) then logically the HEAD reflog should be
-		 * updated too.
-		 * A generic solution implies reverse symref information,
-		 * but finding all symrefs pointing to the given branch
-		 * would be rather costly for this rare event (the direct
-		 * update of a branch) to be worth it.  So let's cheat and
-		 * check with HEAD only which should cover 99% of all usage
-		 * scenarios (even 100% of the default ones).
-		 */
-		unsigned char head_sha1[20];
-		int head_flag;
-		const char *head_ref;
-		head_ref = resolve_ref_unsafe("HEAD", head_sha1,
-					      RESOLVE_REF_READING, &head_flag);
-		if (head_ref && (head_flag & REF_ISSYMREF) &&
-		    !strcmp(head_ref, lock->ref_name))
-			log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
-	}
 	if (commit_ref(lock)) {
 		error("Couldn't set %s", lock->ref_name);
 		unlock_ref(lock);
@@ -3661,7 +3670,8 @@ int transaction_commit(struct ref_transaction *transaction,
 			continue;
 		if (get_packed_ref(update->refname))
 			continue;
-		if (!resolve_ref_unsafe(update->refname, sha1, 1, NULL))
+		if (!resolve_ref_unsafe(update->refname, sha1,
+					RESOLVE_REF_READING, NULL))
 			continue;
 
 		add_packed_ref(update->refname, sha1);