Manages relations on a Model, each Model has it's own instance.
| 10 | |
| 11 | |
| 12 | class RelationsManager: |
| 13 | """ |
| 14 | Manages relations on a Model, each Model has it's own instance. |
| 15 | """ |
| 16 | |
| 17 | def __init__( |
| 18 | self, |
| 19 | related_fields: Optional[list["ForeignKeyField"]] = None, |
| 20 | owner: Optional["Model"] = None, |
| 21 | ) -> None: |
| 22 | self.owner = proxy(owner) |
| 23 | self._related_fields = related_fields or [] |
| 24 | # ``_field_map`` lets ``_get`` build a ``Relation`` lazily by name. |
| 25 | # Holding only the field reference (not a constructed Relation) is |
| 26 | # what skips the per-FK Relation/RelationProxy/QuerysetProxy |
| 27 | # allocation tree on every ``Model.__init__``. |
| 28 | self._field_map: dict[str, "ForeignKeyField"] = { |
| 29 | field.name: field for field in self._related_fields |
| 30 | } |
| 31 | self._related_names = list(self._field_map) |
| 32 | self._relations: dict[str, Relation] = dict() |
| 33 | |
| 34 | def __contains__(self, item: str) -> bool: |
| 35 | """ |
| 36 | Checks if relation with given name is already registered. |
| 37 | |
| 38 | :param item: name of attribute |
| 39 | :type item: str |
| 40 | :return: result of the check |
| 41 | :rtype: bool |
| 42 | """ |
| 43 | return item in self._related_names |
| 44 | |
| 45 | def clear(self) -> None: |
| 46 | for relation in self._relations.values(): |
| 47 | relation.clear() |
| 48 | |
| 49 | def get(self, name: str) -> Optional[Union["Model", Sequence["Model"]]]: |
| 50 | """ |
| 51 | Returns the related model/models if relation is set. |
| 52 | Actual call is delegated to Relation instance registered under relation name. |
| 53 | |
| 54 | :param name: name of the relation |
| 55 | :type name: str |
| 56 | :return: related model or list of related models if set |
| 57 | :rtype: Optional[Union[Model, list[Model]] |
| 58 | """ |
| 59 | relation = self._get(name) |
| 60 | if relation is not None: |
| 61 | return relation.get() |
| 62 | return None # pragma nocover |
| 63 | |
| 64 | @staticmethod |
| 65 | def add(parent: "Model", child: "Model", field: "ForeignKeyField") -> None: |
| 66 | """ |
| 67 | Adds relation on both sides -> meaning on both child and parent models. |
| 68 | One side of the relation is always weakref proxy to avoid circular refs. |
| 69 |
no outgoing calls
no test coverage detected