dal.py 文件源码

def __new__(cls, uri='sqlite://dummy.db', *args, **kwargs):
        if not hasattr(THREAD_LOCAL,'db_instances'):
            THREAD_LOCAL.db_instances = {}
        if not hasattr(THREAD_LOCAL,'db_instances_zombie'):
            THREAD_LOCAL.db_instances_zombie = {}
        if uri == '<zombie>':
            db_uid = kwargs['db_uid'] # a zombie must have a db_uid!
            if db_uid in THREAD_LOCAL.db_instances:
                db_group = THREAD_LOCAL.db_instances[db_uid]
                db = db_group[-1]
            elif db_uid in THREAD_LOCAL.db_instances_zombie:
                db = THREAD_LOCAL.db_instances_zombie[db_uid]
            else:
                db = super(DAL, cls).__new__(cls)
                THREAD_LOCAL.db_instances_zombie[db_uid] = db
        else:
            db_uid = kwargs.get('db_uid',hashlib_md5(repr(uri)).hexdigest())
            if db_uid in THREAD_LOCAL.db_instances_zombie:
                db = THREAD_LOCAL.db_instances_zombie[db_uid]
                del THREAD_LOCAL.db_instances_zombie[db_uid]
            else:
                db = super(DAL, cls).__new__(cls)
            db_group = THREAD_LOCAL.db_instances.get(db_uid,[])
            db_group.append(db)
            THREAD_LOCAL.db_instances[db_uid] = db_group
        db._db_uid = db_uid
        return db