| import functools |
| from collections import namedtuple |
|
|
|
|
| def make_model_tuple(model): |
| """ |
| Take a model or a string of the form "app_label.ModelName" and return a |
| corresponding ("app_label", "modelname") tuple. If a tuple is passed in, |
| assume it's a valid model tuple already and return it unchanged. |
| """ |
| try: |
| if isinstance(model, tuple): |
| model_tuple = model |
| elif isinstance(model, str): |
| app_label, model_name = model.split(".") |
| model_tuple = app_label, model_name.lower() |
| else: |
| model_tuple = model._meta.app_label, model._meta.model_name |
| assert len(model_tuple) == 2 |
| return model_tuple |
| except (ValueError, AssertionError): |
| raise ValueError( |
| "Invalid model reference '%s'. String model references " |
| "must be of the form 'app_label.ModelName'." % model |
| ) |
|
|
|
|
| def resolve_callables(mapping): |
| """ |
| Generate key/value pairs for the given mapping where the values are |
| evaluated if they're callable. |
| """ |
| for k, v in mapping.items(): |
| yield k, v() if callable(v) else v |
|
|
|
|
| def unpickle_named_row(names, values): |
| return create_namedtuple_class(*names)(*values) |
|
|
|
|
| @functools.lru_cache |
| def create_namedtuple_class(*names): |
| |
| |
| def __reduce__(self): |
| return unpickle_named_row, (names, tuple(self)) |
|
|
| return type( |
| "Row", |
| (namedtuple("Row", names),), |
| {"__reduce__": __reduce__, "__slots__": ()}, |
| ) |
|
|
|
|
| class AltersData: |
| """ |
| Make subclasses preserve the alters_data attribute on overridden methods. |
| """ |
|
|
| def __init_subclass__(cls, **kwargs): |
| for fn_name, fn in vars(cls).items(): |
| if callable(fn) and not hasattr(fn, "alters_data"): |
| for base in cls.__bases__: |
| if base_fn := getattr(base, fn_name, None): |
| if hasattr(base_fn, "alters_data"): |
| fn.alters_data = base_fn.alters_data |
| break |
|
|
| super().__init_subclass__(**kwargs) |
|
|
