collection.py 文件源码

def __find_and_modify(self, filter: dict, projection: Optional[Union[list, dict]],
                                sort: Optional[List[tuple]], upsert: Optional[bool] = None,
                                return_document: bool = ReturnDocument.BEFORE, **kwargs) -> MutableMapping:
        """Internal findAndModify helper."""
        common.validate_is_mapping('filter', filter)
        if not isinstance(return_document, bool):
            raise ValueError('return_document must be ReturnDocument.BEFORE or ReturnDocument.AFTER')
        cmd = SON([('findAndModify', self.name),
                   ('query', filter),
                   ('new', return_document)])
        collation = validate_collation_or_none(kwargs.pop('collation', None))
        cmd.update(kwargs)
        if projection is not None:
            cmd['fields'] = helpers._fields_list_to_dict(projection, 'projection')
        if sort is not None:
            cmd['sort'] = helpers._index_document(sort)
        if upsert is not None:
            common.validate_boolean('upsert', upsert)
            cmd['upsert'] = upsert

        connection = await self.database.client.get_connection()
        if connection.max_wire_version >= 4 and 'writeConcern' not in cmd:
            wc_doc = self.write_concern.document
            if wc_doc:
                cmd['writeConcern'] = wc_doc

        out = await connection.command(
            self.database.name, cmd, ReadPreference.PRIMARY, self.codec_options,
            allowable_errors=[_NO_OBJ_ERROR], collation=collation
        )
        helpers._check_write_command_response([(0, out)])
        return out.get('value')