from collections import namedtuple from django.utils.encoding import smart_text from django.db.models.fields import BLANK_CHOICE_DASH # PathInfo is used when converting lookups (fk__somecol). The contents # describe the relation in Model terms (model Options and Fields for both # sides of the relation. The join_field is the field backing the relation. PathInfo = namedtuple('PathInfo', 'from_field to_field from_opts to_opts join_field ' 'm2m direct') class RelatedObject(object): def __init__(self, parent_model, model, field): self.parent_model = parent_model self.model = model self.opts = model._meta self.field = field self.name = '%s:%s' % (self.opts.app_label, self.opts.model_name) self.var_name = self.opts.model_name def get_choices(self, include_blank=True, blank_choice=BLANK_CHOICE_DASH, limit_to_currently_related=False): """Returns choices with a default blank choices included, for use as SelectField choices for this field. Analogue of django.db.models.fields.Field.get_choices, provided initially for utilisation by RelatedFieldListFilter. """ first_choice = include_blank and blank_choice or [] queryset = self.model._default_manager.all() if limit_to_currently_related: queryset = queryset.complex_filter( {'%s__isnull' % self.parent_model._meta.model_name: False}) lst = [(x._get_pk_val(), smart_text(x)) for x in queryset] return first_choice + lst def get_db_prep_lookup(self, lookup_type, value, connection, prepared=False): # Defer to the actual field definition for db prep return self.field.get_db_prep_lookup(lookup_type, value, connection=connection, prepared=prepared) def editable_fields(self): "Get the fields in this class that should be edited inline." return [f for f in self.opts.fields + self.opts.many_to_many if f.editable and f != self.field] def __repr__(self): return "" % (self.name, self.field.name) def get_accessor_name(self): # This method encapsulates the logic that decides what name to give an # accessor descriptor that retrieves related many-to-one or # many-to-many objects. It uses the lower-cased object_name + "_set", # but this can be overridden with the "related_name" option. if self.field.rel.multiple: # If this is a symmetrical m2m relation on self, there is no reverse accessor. if getattr(self.field.rel, 'symmetrical', False) and self.model == self.parent_model: return None return self.field.rel.related_name or (self.opts.model_name + '_set') else: return self.field.rel.related_name or (self.opts.model_name) def get_cache_name(self): return "_%s_cache" % self.get_accessor_name() def get_path_info(self): return self.field.get_reverse_path_info()