831 lines
35 KiB
Python
831 lines
35 KiB
Python
from __future__ import unicode_literals
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import warnings
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from bisect import bisect
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from collections import OrderedDict, defaultdict
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from itertools import chain
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from django.apps import apps
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from django.conf import settings
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from django.core.exceptions import FieldDoesNotExist
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from django.db.models.fields import AutoField
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from django.db.models.fields.proxy import OrderWrt
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from django.db.models.fields.related import ManyToManyField
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from django.utils import six
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from django.utils.datastructures import ImmutableList, OrderedSet
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from django.utils.deprecation import RemovedInDjango20Warning
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from django.utils.encoding import (
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force_text, python_2_unicode_compatible, smart_text,
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)
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from django.utils.functional import cached_property
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from django.utils.lru_cache import lru_cache
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from django.utils.text import camel_case_to_spaces
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from django.utils.translation import override, string_concat
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PROXY_PARENTS = object()
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EMPTY_RELATION_TREE = tuple()
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IMMUTABLE_WARNING = (
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"The return type of '%s' should never be mutated. If you want to manipulate this list "
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"for your own use, make a copy first."
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)
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DEFAULT_NAMES = ('verbose_name', 'verbose_name_plural', 'db_table', 'ordering',
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'unique_together', 'permissions', 'get_latest_by',
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'order_with_respect_to', 'app_label', 'db_tablespace',
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'abstract', 'managed', 'proxy', 'swappable', 'auto_created',
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'index_together', 'apps', 'default_permissions',
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'select_on_save', 'default_related_name')
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class raise_deprecation(object):
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def __init__(self, suggested_alternative):
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self.suggested_alternative = suggested_alternative
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def __call__(self, fn):
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def wrapper(*args, **kwargs):
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warnings.warn(
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"'%s is an unofficial API that has been deprecated. "
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"You may be able to replace it with '%s'" % (
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fn.__name__,
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self.suggested_alternative,
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),
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RemovedInDjango20Warning, stacklevel=2
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)
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return fn(*args, **kwargs)
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return wrapper
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def normalize_together(option_together):
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"""
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option_together can be either a tuple of tuples, or a single
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tuple of two strings. Normalize it to a tuple of tuples, so that
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calling code can uniformly expect that.
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"""
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try:
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if not option_together:
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return ()
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if not isinstance(option_together, (tuple, list)):
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raise TypeError
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first_element = next(iter(option_together))
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if not isinstance(first_element, (tuple, list)):
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option_together = (option_together,)
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# Normalize everything to tuples
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return tuple(tuple(ot) for ot in option_together)
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except TypeError:
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# If the value of option_together isn't valid, return it
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# verbatim; this will be picked up by the check framework later.
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return option_together
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def make_immutable_fields_list(name, data):
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return ImmutableList(data, warning=IMMUTABLE_WARNING % name)
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@python_2_unicode_compatible
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class Options(object):
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FORWARD_PROPERTIES = ('fields', 'many_to_many', 'concrete_fields',
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'local_concrete_fields', '_forward_fields_map')
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REVERSE_PROPERTIES = ('related_objects', 'fields_map', '_relation_tree')
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def __init__(self, meta, app_label=None):
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self._get_fields_cache = {}
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self.proxied_children = []
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self.local_fields = []
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self.local_many_to_many = []
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self.virtual_fields = []
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self.model_name = None
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self.verbose_name = None
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self.verbose_name_plural = None
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self.db_table = ''
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self.ordering = []
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self._ordering_clash = False
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self.unique_together = []
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self.index_together = []
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self.select_on_save = False
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self.default_permissions = ('add', 'change', 'delete')
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self.permissions = []
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self.object_name = None
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self.app_label = app_label
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self.get_latest_by = None
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self.order_with_respect_to = None
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self.db_tablespace = settings.DEFAULT_TABLESPACE
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self.meta = meta
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self.pk = None
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self.has_auto_field = False
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self.auto_field = None
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self.abstract = False
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self.managed = True
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self.proxy = False
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# For any class that is a proxy (including automatically created
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# classes for deferred object loading), proxy_for_model tells us
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# which class this model is proxying. Note that proxy_for_model
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# can create a chain of proxy models. For non-proxy models, the
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# variable is always None.
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self.proxy_for_model = None
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# For any non-abstract class, the concrete class is the model
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# in the end of the proxy_for_model chain. In particular, for
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# concrete models, the concrete_model is always the class itself.
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self.concrete_model = None
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self.swappable = None
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self.parents = OrderedDict()
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self.auto_created = False
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# To handle various inheritance situations, we need to track where
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# managers came from (concrete or abstract base classes). `managers`
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# keeps a list of 3-tuples of the form:
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# (creation_counter, instance, abstract(=True))
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self.managers = []
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# List of all lookups defined in ForeignKey 'limit_choices_to' options
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# from *other* models. Needed for some admin checks. Internal use only.
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self.related_fkey_lookups = []
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# A custom app registry to use, if you're making a separate model set.
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self.apps = apps
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self.default_related_name = None
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@lru_cache(maxsize=None)
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def _map_model(self, link):
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# This helper function is used to allow backwards compatibility with
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# the previous API. No future methods should use this function.
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# It maps a field to (field, model or related_model,) depending on the
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# field type.
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model = link.model._meta.concrete_model
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if model is self.model:
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model = None
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return link, model
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@lru_cache(maxsize=None)
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def _map_model_details(self, link):
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# This helper function is used to allow backwards compatibility with
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# the previous API. No future methods should use this function.
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# This function maps a field to a tuple of:
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# (field, model or related_model, direct, is_m2m) depending on the
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# field type.
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direct = not link.auto_created or link.concrete
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model = link.model._meta.concrete_model
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if model is self.model:
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model = None
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m2m = link.is_relation and link.many_to_many
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return link, model, direct, m2m
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@property
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def app_config(self):
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# Don't go through get_app_config to avoid triggering imports.
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return self.apps.app_configs.get(self.app_label)
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@property
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def installed(self):
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return self.app_config is not None
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@property
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def abstract_managers(self):
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return [
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(counter, instance.name, instance) for counter, instance, abstract
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in self.managers if abstract
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]
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@property
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def concrete_managers(self):
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return [
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(counter, instance.name, instance) for counter, instance, abstract
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in self.managers if not abstract
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]
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def contribute_to_class(self, cls, name):
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from django.db import connection
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from django.db.backends.utils import truncate_name
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cls._meta = self
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self.model = cls
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# First, construct the default values for these options.
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self.object_name = cls.__name__
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self.model_name = self.object_name.lower()
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self.verbose_name = camel_case_to_spaces(self.object_name)
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# Store the original user-defined values for each option,
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# for use when serializing the model definition
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self.original_attrs = {}
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# Next, apply any overridden values from 'class Meta'.
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if self.meta:
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meta_attrs = self.meta.__dict__.copy()
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for name in self.meta.__dict__:
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# Ignore any private attributes that Django doesn't care about.
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# NOTE: We can't modify a dictionary's contents while looping
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# over it, so we loop over the *original* dictionary instead.
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if name.startswith('_'):
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del meta_attrs[name]
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for attr_name in DEFAULT_NAMES:
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if attr_name in meta_attrs:
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setattr(self, attr_name, meta_attrs.pop(attr_name))
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self.original_attrs[attr_name] = getattr(self, attr_name)
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elif hasattr(self.meta, attr_name):
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setattr(self, attr_name, getattr(self.meta, attr_name))
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self.original_attrs[attr_name] = getattr(self, attr_name)
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self.unique_together = normalize_together(self.unique_together)
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self.index_together = normalize_together(self.index_together)
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# verbose_name_plural is a special case because it uses a 's'
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# by default.
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if self.verbose_name_plural is None:
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self.verbose_name_plural = string_concat(self.verbose_name, 's')
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# order_with_respect_and ordering are mutually exclusive.
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self._ordering_clash = bool(self.ordering and self.order_with_respect_to)
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# Any leftover attributes must be invalid.
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if meta_attrs != {}:
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raise TypeError("'class Meta' got invalid attribute(s): %s" % ','.join(meta_attrs.keys()))
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else:
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self.verbose_name_plural = string_concat(self.verbose_name, 's')
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del self.meta
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# If the db_table wasn't provided, use the app_label + model_name.
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if not self.db_table:
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self.db_table = "%s_%s" % (self.app_label, self.model_name)
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self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
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def _prepare(self, model):
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if self.order_with_respect_to:
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# The app registry will not be ready at this point, so we cannot
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# use get_field().
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query = self.order_with_respect_to
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try:
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self.order_with_respect_to = next(
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f for f in self._get_fields(reverse=False)
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if f.name == query or f.attname == query
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)
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except StopIteration:
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raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, query))
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self.ordering = ('_order',)
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if not any(isinstance(field, OrderWrt) for field in model._meta.local_fields):
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model.add_to_class('_order', OrderWrt())
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else:
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self.order_with_respect_to = None
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if self.pk is None:
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if self.parents:
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# Promote the first parent link in lieu of adding yet another
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# field.
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field = next(six.itervalues(self.parents))
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# Look for a local field with the same name as the
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# first parent link. If a local field has already been
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# created, use it instead of promoting the parent
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already_created = [fld for fld in self.local_fields if fld.name == field.name]
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if already_created:
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field = already_created[0]
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field.primary_key = True
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self.setup_pk(field)
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else:
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auto = AutoField(verbose_name='ID', primary_key=True,
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auto_created=True)
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model.add_to_class('id', auto)
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def add_field(self, field, virtual=False):
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# Insert the given field in the order in which it was created, using
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# the "creation_counter" attribute of the field.
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# Move many-to-many related fields from self.fields into
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# self.many_to_many.
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if virtual:
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self.virtual_fields.append(field)
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elif field.is_relation and field.many_to_many:
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self.local_many_to_many.insert(bisect(self.local_many_to_many, field), field)
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else:
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self.local_fields.insert(bisect(self.local_fields, field), field)
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self.setup_pk(field)
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# If the field being added is a relation to another known field,
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# expire the cache on this field and the forward cache on the field
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# being referenced, because there will be new relationships in the
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# cache. Otherwise, expire the cache of references *to* this field.
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# The mechanism for getting at the related model is slightly odd -
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# ideally, we'd just ask for field.related_model. However, related_model
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# is a cached property, and all the models haven't been loaded yet, so
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# we need to make sure we don't cache a string reference.
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if field.is_relation and hasattr(field.remote_field, 'model') and field.remote_field.model:
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try:
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field.remote_field.model._meta._expire_cache(forward=False)
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except AttributeError:
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pass
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self._expire_cache()
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else:
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self._expire_cache(reverse=False)
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def setup_pk(self, field):
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if not self.pk and field.primary_key:
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self.pk = field
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field.serialize = False
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def setup_proxy(self, target):
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"""
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Does the internal setup so that the current model is a proxy for
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"target".
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"""
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self.pk = target._meta.pk
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self.proxy_for_model = target
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self.db_table = target._meta.db_table
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def __repr__(self):
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return '<Options for %s>' % self.object_name
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def __str__(self):
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return "%s.%s" % (smart_text(self.app_label), smart_text(self.model_name))
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@property
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def verbose_name_raw(self):
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"""
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There are a few places where the untranslated verbose name is needed
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(so that we get the same value regardless of currently active
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locale).
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"""
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with override(None):
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return force_text(self.verbose_name)
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@property
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def swapped(self):
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"""
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Has this model been swapped out for another? If so, return the model
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name of the replacement; otherwise, return None.
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For historical reasons, model name lookups using get_model() are
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case insensitive, so we make sure we are case insensitive here.
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"""
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if self.swappable:
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model_label = '%s.%s' % (self.app_label, self.model_name)
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swapped_for = getattr(settings, self.swappable, None)
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if swapped_for:
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try:
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swapped_label, swapped_object = swapped_for.split('.')
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except ValueError:
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# setting not in the format app_label.model_name
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# raising ImproperlyConfigured here causes problems with
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# test cleanup code - instead it is raised in get_user_model
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# or as part of validation.
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return swapped_for
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if '%s.%s' % (swapped_label, swapped_object.lower()) not in (None, model_label):
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return swapped_for
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return None
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@cached_property
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def fields(self):
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"""
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Returns a list of all forward fields on the model and its parents,
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excluding ManyToManyFields.
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Private API intended only to be used by Django itself; get_fields()
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combined with filtering of field properties is the public API for
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obtaining this field list.
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"""
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# For legacy reasons, the fields property should only contain forward
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# fields that are not virtual or with a m2m cardinality. Therefore we
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# pass these three filters as filters to the generator.
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# The third lambda is a longwinded way of checking f.related_model - we don't
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# use that property directly because related_model is a cached property,
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# and all the models may not have been loaded yet; we don't want to cache
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# the string reference to the related_model.
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is_not_an_m2m_field = lambda f: not (f.is_relation and f.many_to_many)
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is_not_a_generic_relation = lambda f: not (f.is_relation and f.one_to_many)
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is_not_a_generic_foreign_key = lambda f: not (
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f.is_relation and f.many_to_one and not (hasattr(f.remote_field, 'model') and f.remote_field.model)
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)
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return make_immutable_fields_list(
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"fields",
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(f for f in self._get_fields(reverse=False) if
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is_not_an_m2m_field(f) and is_not_a_generic_relation(f)
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and is_not_a_generic_foreign_key(f))
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)
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|
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@cached_property
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def concrete_fields(self):
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"""
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Returns a list of all concrete fields on the model and its parents.
|
|
|
|
Private API intended only to be used by Django itself; get_fields()
|
|
combined with filtering of field properties is the public API for
|
|
obtaining this field list.
|
|
"""
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return make_immutable_fields_list(
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"concrete_fields", (f for f in self.fields if f.concrete)
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)
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|
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@cached_property
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|
def local_concrete_fields(self):
|
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"""
|
|
Returns a list of all concrete fields on the model.
|
|
|
|
Private API intended only to be used by Django itself; get_fields()
|
|
combined with filtering of field properties is the public API for
|
|
obtaining this field list.
|
|
"""
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return make_immutable_fields_list(
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"local_concrete_fields", (f for f in self.local_fields if f.concrete)
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)
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|
|
|
@raise_deprecation(suggested_alternative="get_fields()")
|
|
def get_fields_with_model(self):
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return [self._map_model(f) for f in self.get_fields()]
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|
|
|
@raise_deprecation(suggested_alternative="get_fields()")
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|
def get_concrete_fields_with_model(self):
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return [self._map_model(f) for f in self.concrete_fields]
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|
|
|
@cached_property
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|
def many_to_many(self):
|
|
"""
|
|
Returns a list of all many to many fields on the model and its parents.
|
|
|
|
Private API intended only to be used by Django itself; get_fields()
|
|
combined with filtering of field properties is the public API for
|
|
obtaining this list.
|
|
"""
|
|
return make_immutable_fields_list(
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"many_to_many",
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(f for f in self._get_fields(reverse=False)
|
|
if f.is_relation and f.many_to_many)
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)
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|
|
@cached_property
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|
def related_objects(self):
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"""
|
|
Returns all related objects pointing to the current model. The related
|
|
objects can come from a one-to-one, one-to-many, or many-to-many field
|
|
relation type.
|
|
|
|
Private API intended only to be used by Django itself; get_fields()
|
|
combined with filtering of field properties is the public API for
|
|
obtaining this field list.
|
|
"""
|
|
all_related_fields = self._get_fields(forward=False, reverse=True, include_hidden=True)
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|
return make_immutable_fields_list(
|
|
"related_objects",
|
|
(obj for obj in all_related_fields
|
|
if not obj.hidden or obj.field.many_to_many)
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|
)
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|
|
|
@raise_deprecation(suggested_alternative="get_fields()")
|
|
def get_m2m_with_model(self):
|
|
return [self._map_model(f) for f in self.many_to_many]
|
|
|
|
@cached_property
|
|
def _forward_fields_map(self):
|
|
res = {}
|
|
fields = self._get_fields(reverse=False)
|
|
for field in fields:
|
|
res[field.name] = field
|
|
# Due to the way Django's internals work, get_field() should also
|
|
# be able to fetch a field by attname. In the case of a concrete
|
|
# field with relation, includes the *_id name too
|
|
try:
|
|
res[field.attname] = field
|
|
except AttributeError:
|
|
pass
|
|
return res
|
|
|
|
@cached_property
|
|
def fields_map(self):
|
|
res = {}
|
|
fields = self._get_fields(forward=False, include_hidden=True)
|
|
for field in fields:
|
|
res[field.name] = field
|
|
# Due to the way Django's internals work, get_field() should also
|
|
# be able to fetch a field by attname. In the case of a concrete
|
|
# field with relation, includes the *_id name too
|
|
try:
|
|
res[field.attname] = field
|
|
except AttributeError:
|
|
pass
|
|
return res
|
|
|
|
def get_field(self, field_name, many_to_many=None):
|
|
"""
|
|
Returns a field instance given a field name. The field can be either a
|
|
forward or reverse field, unless many_to_many is specified; if it is,
|
|
only forward fields will be returned.
|
|
|
|
The many_to_many argument exists for backwards compatibility reasons;
|
|
it has been deprecated and will be removed in Django 2.0.
|
|
"""
|
|
m2m_in_kwargs = many_to_many is not None
|
|
if m2m_in_kwargs:
|
|
# Always throw a warning if many_to_many is used regardless of
|
|
# whether it alters the return type or not.
|
|
warnings.warn(
|
|
"The 'many_to_many' argument on get_field() is deprecated; "
|
|
"use a filter on field.many_to_many instead.",
|
|
RemovedInDjango20Warning
|
|
)
|
|
|
|
try:
|
|
# In order to avoid premature loading of the relation tree
|
|
# (expensive) we prefer checking if the field is a forward field.
|
|
field = self._forward_fields_map[field_name]
|
|
|
|
if many_to_many is False and field.many_to_many:
|
|
raise FieldDoesNotExist(
|
|
'%s has no field named %r' % (self.object_name, field_name)
|
|
)
|
|
|
|
return field
|
|
except KeyError:
|
|
# If the app registry is not ready, reverse fields are
|
|
# unavailable, therefore we throw a FieldDoesNotExist exception.
|
|
if not self.apps.models_ready:
|
|
raise FieldDoesNotExist(
|
|
"%s has no field named %r. The app cache isn't ready yet, "
|
|
"so if this is an auto-created related field, it won't "
|
|
"be available yet." % (self.object_name, field_name)
|
|
)
|
|
|
|
try:
|
|
if m2m_in_kwargs:
|
|
# Previous API does not allow searching reverse fields.
|
|
raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, field_name))
|
|
|
|
# Retrieve field instance by name from cached or just-computed
|
|
# field map.
|
|
return self.fields_map[field_name]
|
|
except KeyError:
|
|
raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, field_name))
|
|
|
|
@raise_deprecation(suggested_alternative="get_field()")
|
|
def get_field_by_name(self, name):
|
|
return self._map_model_details(self.get_field(name))
|
|
|
|
@raise_deprecation(suggested_alternative="get_fields()")
|
|
def get_all_field_names(self):
|
|
names = set()
|
|
fields = self.get_fields()
|
|
for field in fields:
|
|
# For backwards compatibility GenericForeignKey should not be
|
|
# included in the results.
|
|
if field.is_relation and field.many_to_one and field.related_model is None:
|
|
continue
|
|
# Relations to child proxy models should not be included.
|
|
if (field.model != self.model and
|
|
field.model._meta.concrete_model == self.concrete_model):
|
|
continue
|
|
|
|
names.add(field.name)
|
|
if hasattr(field, 'attname'):
|
|
names.add(field.attname)
|
|
return list(names)
|
|
|
|
@raise_deprecation(suggested_alternative="get_fields()")
|
|
def get_all_related_objects(self, local_only=False, include_hidden=False,
|
|
include_proxy_eq=False):
|
|
|
|
include_parents = True if local_only is False else PROXY_PARENTS
|
|
fields = self._get_fields(
|
|
forward=False, reverse=True,
|
|
include_parents=include_parents,
|
|
include_hidden=include_hidden,
|
|
)
|
|
fields = (obj for obj in fields if not isinstance(obj.field, ManyToManyField))
|
|
if include_proxy_eq:
|
|
children = chain.from_iterable(c._relation_tree
|
|
for c in self.concrete_model._meta.proxied_children
|
|
if c is not self)
|
|
relations = (f.remote_field for f in children
|
|
if include_hidden or not f.remote_field.field.remote_field.is_hidden())
|
|
fields = chain(fields, relations)
|
|
return list(fields)
|
|
|
|
@raise_deprecation(suggested_alternative="get_fields()")
|
|
def get_all_related_objects_with_model(self, local_only=False, include_hidden=False,
|
|
include_proxy_eq=False):
|
|
return [
|
|
self._map_model(f) for f in self.get_all_related_objects(
|
|
local_only=local_only,
|
|
include_hidden=include_hidden,
|
|
include_proxy_eq=include_proxy_eq,
|
|
)
|
|
]
|
|
|
|
@raise_deprecation(suggested_alternative="get_fields()")
|
|
def get_all_related_many_to_many_objects(self, local_only=False):
|
|
include_parents = True if local_only is not True else PROXY_PARENTS
|
|
fields = self._get_fields(
|
|
forward=False, reverse=True,
|
|
include_parents=include_parents, include_hidden=True
|
|
)
|
|
return [obj for obj in fields if isinstance(obj.field, ManyToManyField)]
|
|
|
|
@raise_deprecation(suggested_alternative="get_fields()")
|
|
def get_all_related_m2m_objects_with_model(self):
|
|
fields = self._get_fields(forward=False, reverse=True, include_hidden=True)
|
|
return [self._map_model(obj) for obj in fields if isinstance(obj.field, ManyToManyField)]
|
|
|
|
def get_base_chain(self, model):
|
|
"""
|
|
Returns a list of parent classes leading to 'model' (order from closet
|
|
to most distant ancestor). This has to handle the case were 'model' is
|
|
a grandparent or even more distant relation.
|
|
"""
|
|
if not self.parents:
|
|
return None
|
|
if model in self.parents:
|
|
return [model]
|
|
for parent in self.parents:
|
|
res = parent._meta.get_base_chain(model)
|
|
if res:
|
|
res.insert(0, parent)
|
|
return res
|
|
return None
|
|
|
|
def get_parent_list(self):
|
|
"""
|
|
Returns all the ancestors of this model as a list ordered by MRO.
|
|
Useful for determining if something is an ancestor, regardless of lineage.
|
|
"""
|
|
result = OrderedSet(self.parents)
|
|
for parent in self.parents:
|
|
for ancestor in parent._meta.get_parent_list():
|
|
result.add(ancestor)
|
|
return list(result)
|
|
|
|
def get_ancestor_link(self, ancestor):
|
|
"""
|
|
Returns the field on the current model which points to the given
|
|
"ancestor". This is possible an indirect link (a pointer to a parent
|
|
model, which points, eventually, to the ancestor). Used when
|
|
constructing table joins for model inheritance.
|
|
|
|
Returns None if the model isn't an ancestor of this one.
|
|
"""
|
|
if ancestor in self.parents:
|
|
return self.parents[ancestor]
|
|
for parent in self.parents:
|
|
# Tries to get a link field from the immediate parent
|
|
parent_link = parent._meta.get_ancestor_link(ancestor)
|
|
if parent_link:
|
|
# In case of a proxied model, the first link
|
|
# of the chain to the ancestor is that parent
|
|
# links
|
|
return self.parents[parent] or parent_link
|
|
|
|
def _populate_directed_relation_graph(self):
|
|
"""
|
|
This method is used by each model to find its reverse objects. As this
|
|
method is very expensive and is accessed frequently (it looks up every
|
|
field in a model, in every app), it is computed on first access and then
|
|
is set as a property on every model.
|
|
"""
|
|
related_objects_graph = defaultdict(list)
|
|
|
|
all_models = self.apps.get_models(include_auto_created=True)
|
|
for model in all_models:
|
|
# Abstract model's fields are copied to child models, hence we will
|
|
# see the fields from the child models.
|
|
if model._meta.abstract:
|
|
continue
|
|
fields_with_relations = (
|
|
f for f in model._meta._get_fields(reverse=False, include_parents=False)
|
|
if f.is_relation and f.related_model is not None
|
|
)
|
|
for f in fields_with_relations:
|
|
if not isinstance(f.remote_field.model, six.string_types):
|
|
related_objects_graph[f.remote_field.model._meta].append(f)
|
|
|
|
for model in all_models:
|
|
# Set the relation_tree using the internal __dict__. In this way
|
|
# we avoid calling the cached property. In attribute lookup,
|
|
# __dict__ takes precedence over a data descriptor (such as
|
|
# @cached_property). This means that the _meta._relation_tree is
|
|
# only called if related_objects is not in __dict__.
|
|
related_objects = related_objects_graph[model._meta]
|
|
model._meta.__dict__['_relation_tree'] = related_objects
|
|
# It seems it is possible that self is not in all_models, so guard
|
|
# against that with default for get().
|
|
return self.__dict__.get('_relation_tree', EMPTY_RELATION_TREE)
|
|
|
|
@cached_property
|
|
def _relation_tree(self):
|
|
return self._populate_directed_relation_graph()
|
|
|
|
def _expire_cache(self, forward=True, reverse=True):
|
|
# This method is usually called by apps.cache_clear(), when the
|
|
# registry is finalized, or when a new field is added.
|
|
properties_to_expire = []
|
|
if forward:
|
|
properties_to_expire.extend(self.FORWARD_PROPERTIES)
|
|
if reverse and not self.abstract:
|
|
properties_to_expire.extend(self.REVERSE_PROPERTIES)
|
|
|
|
for cache_key in properties_to_expire:
|
|
try:
|
|
delattr(self, cache_key)
|
|
except AttributeError:
|
|
pass
|
|
|
|
self._get_fields_cache = {}
|
|
|
|
def get_fields(self, include_parents=True, include_hidden=False):
|
|
"""
|
|
Returns a list of fields associated to the model. By default will only
|
|
return forward fields. This can be changed by enabling or disabling
|
|
field types using the parameters:
|
|
|
|
- include_parents: include fields derived from inheritance
|
|
- include_hidden: include fields that have a related_name that
|
|
starts with a "+"
|
|
"""
|
|
if include_parents is False:
|
|
include_parents = PROXY_PARENTS
|
|
return self._get_fields(include_parents=include_parents, include_hidden=include_hidden)
|
|
|
|
def _get_fields(self, forward=True, reverse=True, include_parents=True, include_hidden=False,
|
|
seen_models=None):
|
|
"""
|
|
Internal helper function to return fields of the model.
|
|
* If forward=True, then fields defined on this model are returned.
|
|
* If reverse=True, then relations pointing to this model are returned.
|
|
* If include_hidden=True, then fields with is_hidden=True are returned.
|
|
* The include_parents argument toggles if fields from parent models
|
|
should be included. It has three values: True, False, and
|
|
PROXY_PARENTS. When set to PROXY_PARENTS, the call will return all
|
|
fields defined for the current model or any of its parents in the
|
|
parent chain to the model's concrete model.
|
|
"""
|
|
if include_parents not in (True, False, PROXY_PARENTS):
|
|
raise TypeError("Invalid argument for include_parents: %s" % (include_parents,))
|
|
# This helper function is used to allow recursion in ``get_fields()``
|
|
# implementation and to provide a fast way for Django's internals to
|
|
# access specific subsets of fields.
|
|
|
|
# We must keep track of which models we have already seen. Otherwise we
|
|
# could include the same field multiple times from different models.
|
|
topmost_call = False
|
|
if seen_models is None:
|
|
seen_models = set()
|
|
topmost_call = True
|
|
seen_models.add(self.model)
|
|
|
|
# Creates a cache key composed of all arguments
|
|
cache_key = (forward, reverse, include_parents, include_hidden, topmost_call)
|
|
|
|
try:
|
|
# In order to avoid list manipulation. Always return a shallow copy
|
|
# of the results.
|
|
return self._get_fields_cache[cache_key]
|
|
except KeyError:
|
|
pass
|
|
|
|
fields = []
|
|
# Recursively call _get_fields() on each parent, with the same
|
|
# options provided in this call.
|
|
if include_parents is not False:
|
|
for parent in self.parents:
|
|
# In diamond inheritance it is possible that we see the same
|
|
# model from two different routes. In that case, avoid adding
|
|
# fields from the same parent again.
|
|
if parent in seen_models:
|
|
continue
|
|
if (parent._meta.concrete_model != self.concrete_model and
|
|
include_parents == PROXY_PARENTS):
|
|
continue
|
|
for obj in parent._meta._get_fields(
|
|
forward=forward, reverse=reverse, include_parents=include_parents,
|
|
include_hidden=include_hidden, seen_models=seen_models):
|
|
if hasattr(obj, 'parent_link') and obj.parent_link:
|
|
continue
|
|
fields.append(obj)
|
|
if reverse:
|
|
# Tree is computed once and cached until the app cache is expired.
|
|
# It is composed of a list of fields pointing to the current model
|
|
# from other models.
|
|
all_fields = self._relation_tree
|
|
for field in all_fields:
|
|
# If hidden fields should be included or the relation is not
|
|
# intentionally hidden, add to the fields dict.
|
|
if include_hidden or not field.remote_field.hidden:
|
|
fields.append(field.remote_field)
|
|
|
|
if forward:
|
|
fields.extend(
|
|
field for field in chain(self.local_fields, self.local_many_to_many)
|
|
)
|
|
# Virtual fields are recopied to each child model, and they get a
|
|
# different model as field.model in each child. Hence we have to
|
|
# add the virtual fields separately from the topmost call. If we
|
|
# did this recursively similar to local_fields, we would get field
|
|
# instances with field.model != self.model.
|
|
if topmost_call:
|
|
fields.extend(
|
|
f for f in self.virtual_fields
|
|
)
|
|
|
|
# In order to avoid list manipulation. Always
|
|
# return a shallow copy of the results
|
|
fields = make_immutable_fields_list("get_fields()", fields)
|
|
|
|
# Store result into cache for later access
|
|
self._get_fields_cache[cache_key] = fields
|
|
return fields
|