def get_last_tid(self):
        try:
            spec = {'tid': {'$gt': 0}}
            sort = [('tid', -1)]
            row = self.db.docs.find_one(spec, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return row['tid']
        return 0
def is_commit_id_equal(cls, dest, name):
        """
        Return whether the current commit hash equals the given name.

        Args:
          dest: the repository directory.
          name: a string name.
        """
        if not name:
            # Then avoid an unnecessary subprocess call.
            return False

        return cls.get_revision(dest) == name