Function lock_ref_oid_basic

refs/files-backend.c:1210–1258

* Locks a ref returning the lock on success and NULL on failure. */

 * Locks a ref returning the lock on success and NULL on failure.
 */
static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
					   const char *refname,
					   struct strbuf *err)
{
	struct strbuf ref_file = STRBUF_INIT;
	struct ref_lock *lock;
	struct create_reflock_cb cb_data;

	files_assert_main_repository(refs, "lock_ref_oid_basic");
	assert(err);

	CALLOC_ARRAY(lock, 1);

	files_ref_path(refs, &ref_file, refname);

	/*
	 * If the ref did not exist and we are creating it, make sure
	 * there is no existing packed ref whose name begins with our
	 * refname, nor a packed ref whose name is a proper prefix of
	 * our refname.
	 */
	if (is_null_oid(&lock->old_oid) &&
	    refs_verify_refname_available(refs->packed_ref_store, refname,
					  NULL, NULL, 0, err))
		goto error_return;

	lock->ref_name = xstrdup(refname);
	lock->count = 1;
	cb_data.lk   = &lock->lk;
	cb_data.repo = refs->base.repo;

	if (raceproof_create_file(ref_file.buf, create_reflock, &cb_data)) {
		unable_to_lock_message(ref_file.buf, errno, err);
		goto error_return;
	}

	if (!refs_resolve_ref_unsafe(&refs->base, lock->ref_name, 0,
				     &lock->old_oid, NULL))
		oidclr(&lock->old_oid, refs->base.repo->hash_algo);
	goto out;

 error_return:
	unlock_ref(lock);
	lock = NULL;

 out:
	strbuf_release(&ref_file);
	return lock;
}

struct ref_to_prune {
	struct ref_to_prune *next;