dal.py 文件源码

def find_driver(self, adapter_args, uri=None):
        self.adapter_args = adapter_args
        if getattr(self, 'driver', None) != None:
            return
        drivers_available = [driver for driver in self.drivers
                             if driver in globals()]
        if uri:
            items = uri.split('://', 1)[0].split(':')
            request_driver = items[1] if len(items) > 1 else None
        else:
            request_driver = None
        request_driver = request_driver or adapter_args.get('driver')
        if request_driver:
            if request_driver in drivers_available:
                self.driver_name = request_driver
                self.driver = globals().get(request_driver)
            else:
                raise RuntimeError("driver %s not available" % request_driver)
        elif drivers_available:
            self.driver_name = drivers_available[0]
            self.driver = globals().get(self.driver_name)
        else:
            raise RuntimeError("no driver available %s" % str(self.drivers))