896 lines
36 KiB
Python
896 lines
36 KiB
Python
import bisect
|
|
import copy
|
|
import inspect
|
|
from collections import defaultdict
|
|
|
|
from django.apps import apps
|
|
from django.conf import settings
|
|
from django.core.exceptions import FieldDoesNotExist, ImproperlyConfigured
|
|
from django.db import connections
|
|
from django.db.models import AutoField, Manager, OrderWrt, UniqueConstraint
|
|
from django.db.models.query_utils import PathInfo
|
|
from django.utils.datastructures import ImmutableList, OrderedSet
|
|
from django.utils.functional import cached_property
|
|
from django.utils.module_loading import import_string
|
|
from django.utils.text import camel_case_to_spaces, format_lazy
|
|
from django.utils.translation import override
|
|
|
|
PROXY_PARENTS = object()
|
|
|
|
EMPTY_RELATION_TREE = ()
|
|
|
|
IMMUTABLE_WARNING = (
|
|
"The return type of '%s' should never be mutated. If you want to manipulate this list "
|
|
"for your own use, make a copy first."
|
|
)
|
|
|
|
DEFAULT_NAMES = (
|
|
'verbose_name', 'verbose_name_plural', 'db_table', 'ordering',
|
|
'unique_together', 'permissions', 'get_latest_by', 'order_with_respect_to',
|
|
'app_label', 'db_tablespace', 'abstract', 'managed', 'proxy', 'swappable',
|
|
'auto_created', 'index_together', 'apps', 'default_permissions',
|
|
'select_on_save', 'default_related_name', 'required_db_features',
|
|
'required_db_vendor', 'base_manager_name', 'default_manager_name',
|
|
'indexes', 'constraints',
|
|
)
|
|
|
|
|
|
def normalize_together(option_together):
|
|
"""
|
|
option_together can be either a tuple of tuples, or a single
|
|
tuple of two strings. Normalize it to a tuple of tuples, so that
|
|
calling code can uniformly expect that.
|
|
"""
|
|
try:
|
|
if not option_together:
|
|
return ()
|
|
if not isinstance(option_together, (tuple, list)):
|
|
raise TypeError
|
|
first_element = option_together[0]
|
|
if not isinstance(first_element, (tuple, list)):
|
|
option_together = (option_together,)
|
|
# Normalize everything to tuples
|
|
return tuple(tuple(ot) for ot in option_together)
|
|
except TypeError:
|
|
# If the value of option_together isn't valid, return it
|
|
# verbatim; this will be picked up by the check framework later.
|
|
return option_together
|
|
|
|
|
|
def make_immutable_fields_list(name, data):
|
|
return ImmutableList(data, warning=IMMUTABLE_WARNING % name)
|
|
|
|
|
|
class Options:
|
|
FORWARD_PROPERTIES = {
|
|
'fields', 'many_to_many', 'concrete_fields', 'local_concrete_fields',
|
|
'_forward_fields_map', 'managers', 'managers_map', 'base_manager',
|
|
'default_manager',
|
|
}
|
|
REVERSE_PROPERTIES = {'related_objects', 'fields_map', '_relation_tree'}
|
|
|
|
default_apps = apps
|
|
|
|
def __init__(self, meta, app_label=None):
|
|
self._get_fields_cache = {}
|
|
self.local_fields = []
|
|
self.local_many_to_many = []
|
|
self.private_fields = []
|
|
self.local_managers = []
|
|
self.base_manager_name = None
|
|
self.default_manager_name = None
|
|
self.model_name = None
|
|
self.verbose_name = None
|
|
self.verbose_name_plural = None
|
|
self.db_table = ''
|
|
self.ordering = []
|
|
self._ordering_clash = False
|
|
self.indexes = []
|
|
self.constraints = []
|
|
self.unique_together = []
|
|
self.index_together = []
|
|
self.select_on_save = False
|
|
self.default_permissions = ('add', 'change', 'delete', 'view')
|
|
self.permissions = []
|
|
self.object_name = None
|
|
self.app_label = app_label
|
|
self.get_latest_by = None
|
|
self.order_with_respect_to = None
|
|
self.db_tablespace = settings.DEFAULT_TABLESPACE
|
|
self.required_db_features = []
|
|
self.required_db_vendor = None
|
|
self.meta = meta
|
|
self.pk = None
|
|
self.auto_field = None
|
|
self.abstract = False
|
|
self.managed = True
|
|
self.proxy = False
|
|
# For any class that is a proxy (including automatically created
|
|
# classes for deferred object loading), proxy_for_model tells us
|
|
# which class this model is proxying. Note that proxy_for_model
|
|
# can create a chain of proxy models. For non-proxy models, the
|
|
# variable is always None.
|
|
self.proxy_for_model = None
|
|
# For any non-abstract class, the concrete class is the model
|
|
# in the end of the proxy_for_model chain. In particular, for
|
|
# concrete models, the concrete_model is always the class itself.
|
|
self.concrete_model = None
|
|
self.swappable = None
|
|
self.parents = {}
|
|
self.auto_created = False
|
|
|
|
# List of all lookups defined in ForeignKey 'limit_choices_to' options
|
|
# from *other* models. Needed for some admin checks. Internal use only.
|
|
self.related_fkey_lookups = []
|
|
|
|
# A custom app registry to use, if you're making a separate model set.
|
|
self.apps = self.default_apps
|
|
|
|
self.default_related_name = None
|
|
|
|
@property
|
|
def label(self):
|
|
return '%s.%s' % (self.app_label, self.object_name)
|
|
|
|
@property
|
|
def label_lower(self):
|
|
return '%s.%s' % (self.app_label, self.model_name)
|
|
|
|
@property
|
|
def app_config(self):
|
|
# Don't go through get_app_config to avoid triggering imports.
|
|
return self.apps.app_configs.get(self.app_label)
|
|
|
|
def contribute_to_class(self, cls, name):
|
|
from django.db import connection
|
|
from django.db.backends.utils import truncate_name
|
|
|
|
cls._meta = self
|
|
self.model = cls
|
|
# First, construct the default values for these options.
|
|
self.object_name = cls.__name__
|
|
self.model_name = self.object_name.lower()
|
|
self.verbose_name = camel_case_to_spaces(self.object_name)
|
|
|
|
# Store the original user-defined values for each option,
|
|
# for use when serializing the model definition
|
|
self.original_attrs = {}
|
|
|
|
# Next, apply any overridden values from 'class Meta'.
|
|
if self.meta:
|
|
meta_attrs = self.meta.__dict__.copy()
|
|
for name in self.meta.__dict__:
|
|
# Ignore any private attributes that Django doesn't care about.
|
|
# NOTE: We can't modify a dictionary's contents while looping
|
|
# over it, so we loop over the *original* dictionary instead.
|
|
if name.startswith('_'):
|
|
del meta_attrs[name]
|
|
for attr_name in DEFAULT_NAMES:
|
|
if attr_name in meta_attrs:
|
|
setattr(self, attr_name, meta_attrs.pop(attr_name))
|
|
self.original_attrs[attr_name] = getattr(self, attr_name)
|
|
elif hasattr(self.meta, attr_name):
|
|
setattr(self, attr_name, getattr(self.meta, attr_name))
|
|
self.original_attrs[attr_name] = getattr(self, attr_name)
|
|
|
|
self.unique_together = normalize_together(self.unique_together)
|
|
self.index_together = normalize_together(self.index_together)
|
|
# App label/class name interpolation for names of constraints and
|
|
# indexes.
|
|
if not getattr(cls._meta, 'abstract', False):
|
|
for attr_name in {'constraints', 'indexes'}:
|
|
objs = getattr(self, attr_name, [])
|
|
setattr(self, attr_name, self._format_names_with_class(cls, objs))
|
|
|
|
# verbose_name_plural is a special case because it uses a 's'
|
|
# by default.
|
|
if self.verbose_name_plural is None:
|
|
self.verbose_name_plural = format_lazy('{}s', self.verbose_name)
|
|
|
|
# order_with_respect_and ordering are mutually exclusive.
|
|
self._ordering_clash = bool(self.ordering and self.order_with_respect_to)
|
|
|
|
# Any leftover attributes must be invalid.
|
|
if meta_attrs != {}:
|
|
raise TypeError("'class Meta' got invalid attribute(s): %s" % ','.join(meta_attrs))
|
|
else:
|
|
self.verbose_name_plural = format_lazy('{}s', self.verbose_name)
|
|
del self.meta
|
|
|
|
# If the db_table wasn't provided, use the app_label + model_name.
|
|
if not self.db_table:
|
|
self.db_table = "%s_%s" % (self.app_label, self.model_name)
|
|
self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
|
|
|
|
def _format_names_with_class(self, cls, objs):
|
|
"""App label/class name interpolation for object names."""
|
|
new_objs = []
|
|
for obj in objs:
|
|
obj = obj.clone()
|
|
obj.name = obj.name % {
|
|
'app_label': cls._meta.app_label.lower(),
|
|
'class': cls.__name__.lower(),
|
|
}
|
|
new_objs.append(obj)
|
|
return new_objs
|
|
|
|
def _get_default_pk_class(self):
|
|
pk_class_path = getattr(
|
|
self.app_config,
|
|
'default_auto_field',
|
|
settings.DEFAULT_AUTO_FIELD,
|
|
)
|
|
if self.app_config and self.app_config._is_default_auto_field_overridden:
|
|
app_config_class = type(self.app_config)
|
|
source = (
|
|
f'{app_config_class.__module__}.'
|
|
f'{app_config_class.__qualname__}.default_auto_field'
|
|
)
|
|
else:
|
|
source = 'DEFAULT_AUTO_FIELD'
|
|
if not pk_class_path:
|
|
raise ImproperlyConfigured(f'{source} must not be empty.')
|
|
try:
|
|
pk_class = import_string(pk_class_path)
|
|
except ImportError as e:
|
|
msg = (
|
|
f"{source} refers to the module '{pk_class_path}' that could "
|
|
f"not be imported."
|
|
)
|
|
raise ImproperlyConfigured(msg) from e
|
|
if not issubclass(pk_class, AutoField):
|
|
raise ValueError(
|
|
f"Primary key '{pk_class_path}' referred by {source} must "
|
|
f"subclass AutoField."
|
|
)
|
|
return pk_class
|
|
|
|
def _prepare(self, model):
|
|
if self.order_with_respect_to:
|
|
# The app registry will not be ready at this point, so we cannot
|
|
# use get_field().
|
|
query = self.order_with_respect_to
|
|
try:
|
|
self.order_with_respect_to = next(
|
|
f for f in self._get_fields(reverse=False)
|
|
if f.name == query or f.attname == query
|
|
)
|
|
except StopIteration:
|
|
raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, query))
|
|
|
|
self.ordering = ('_order',)
|
|
if not any(isinstance(field, OrderWrt) for field in model._meta.local_fields):
|
|
model.add_to_class('_order', OrderWrt())
|
|
else:
|
|
self.order_with_respect_to = None
|
|
|
|
if self.pk is None:
|
|
if self.parents:
|
|
# Promote the first parent link in lieu of adding yet another
|
|
# field.
|
|
field = next(iter(self.parents.values()))
|
|
# Look for a local field with the same name as the
|
|
# first parent link. If a local field has already been
|
|
# created, use it instead of promoting the parent
|
|
already_created = [fld for fld in self.local_fields if fld.name == field.name]
|
|
if already_created:
|
|
field = already_created[0]
|
|
field.primary_key = True
|
|
self.setup_pk(field)
|
|
else:
|
|
pk_class = self._get_default_pk_class()
|
|
auto = pk_class(verbose_name='ID', primary_key=True, auto_created=True)
|
|
model.add_to_class('id', auto)
|
|
|
|
def add_manager(self, manager):
|
|
self.local_managers.append(manager)
|
|
self._expire_cache()
|
|
|
|
def add_field(self, field, private=False):
|
|
# Insert the given field in the order in which it was created, using
|
|
# the "creation_counter" attribute of the field.
|
|
# Move many-to-many related fields from self.fields into
|
|
# self.many_to_many.
|
|
if private:
|
|
self.private_fields.append(field)
|
|
elif field.is_relation and field.many_to_many:
|
|
bisect.insort(self.local_many_to_many, field)
|
|
else:
|
|
bisect.insort(self.local_fields, field)
|
|
self.setup_pk(field)
|
|
|
|
# If the field being added is a relation to another known field,
|
|
# expire the cache on this field and the forward cache on the field
|
|
# being referenced, because there will be new relationships in the
|
|
# cache. Otherwise, expire the cache of references *to* this field.
|
|
# The mechanism for getting at the related model is slightly odd -
|
|
# ideally, we'd just ask for field.related_model. However, related_model
|
|
# is a cached property, and all the models haven't been loaded yet, so
|
|
# we need to make sure we don't cache a string reference.
|
|
if field.is_relation and hasattr(field.remote_field, 'model') and field.remote_field.model:
|
|
try:
|
|
field.remote_field.model._meta._expire_cache(forward=False)
|
|
except AttributeError:
|
|
pass
|
|
self._expire_cache()
|
|
else:
|
|
self._expire_cache(reverse=False)
|
|
|
|
def setup_pk(self, field):
|
|
if not self.pk and field.primary_key:
|
|
self.pk = field
|
|
field.serialize = False
|
|
|
|
def setup_proxy(self, target):
|
|
"""
|
|
Do the internal setup so that the current model is a proxy for
|
|
"target".
|
|
"""
|
|
self.pk = target._meta.pk
|
|
self.proxy_for_model = target
|
|
self.db_table = target._meta.db_table
|
|
|
|
def __repr__(self):
|
|
return '<Options for %s>' % self.object_name
|
|
|
|
def __str__(self):
|
|
return self.label_lower
|
|
|
|
def can_migrate(self, connection):
|
|
"""
|
|
Return True if the model can/should be migrated on the `connection`.
|
|
`connection` can be either a real connection or a connection alias.
|
|
"""
|
|
if self.proxy or self.swapped or not self.managed:
|
|
return False
|
|
if isinstance(connection, str):
|
|
connection = connections[connection]
|
|
if self.required_db_vendor:
|
|
return self.required_db_vendor == connection.vendor
|
|
if self.required_db_features:
|
|
return all(getattr(connection.features, feat, False)
|
|
for feat in self.required_db_features)
|
|
return True
|
|
|
|
@property
|
|
def verbose_name_raw(self):
|
|
"""Return the untranslated verbose name."""
|
|
with override(None):
|
|
return str(self.verbose_name)
|
|
|
|
@property
|
|
def swapped(self):
|
|
"""
|
|
Has this model been swapped out for another? If so, return the model
|
|
name of the replacement; otherwise, return None.
|
|
|
|
For historical reasons, model name lookups using get_model() are
|
|
case insensitive, so we make sure we are case insensitive here.
|
|
"""
|
|
if self.swappable:
|
|
swapped_for = getattr(settings, self.swappable, None)
|
|
if swapped_for:
|
|
try:
|
|
swapped_label, swapped_object = swapped_for.split('.')
|
|
except ValueError:
|
|
# setting not in the format app_label.model_name
|
|
# raising ImproperlyConfigured here causes problems with
|
|
# test cleanup code - instead it is raised in get_user_model
|
|
# or as part of validation.
|
|
return swapped_for
|
|
|
|
if '%s.%s' % (swapped_label, swapped_object.lower()) != self.label_lower:
|
|
return swapped_for
|
|
return None
|
|
|
|
@cached_property
|
|
def managers(self):
|
|
managers = []
|
|
seen_managers = set()
|
|
bases = (b for b in self.model.mro() if hasattr(b, '_meta'))
|
|
for depth, base in enumerate(bases):
|
|
for manager in base._meta.local_managers:
|
|
if manager.name in seen_managers:
|
|
continue
|
|
|
|
manager = copy.copy(manager)
|
|
manager.model = self.model
|
|
seen_managers.add(manager.name)
|
|
managers.append((depth, manager.creation_counter, manager))
|
|
|
|
return make_immutable_fields_list(
|
|
"managers",
|
|
(m[2] for m in sorted(managers)),
|
|
)
|
|
|
|
@cached_property
|
|
def managers_map(self):
|
|
return {manager.name: manager for manager in self.managers}
|
|
|
|
@cached_property
|
|
def base_manager(self):
|
|
base_manager_name = self.base_manager_name
|
|
if not base_manager_name:
|
|
# Get the first parent's base_manager_name if there's one.
|
|
for parent in self.model.mro()[1:]:
|
|
if hasattr(parent, '_meta'):
|
|
if parent._base_manager.name != '_base_manager':
|
|
base_manager_name = parent._base_manager.name
|
|
break
|
|
|
|
if base_manager_name:
|
|
try:
|
|
return self.managers_map[base_manager_name]
|
|
except KeyError:
|
|
raise ValueError(
|
|
"%s has no manager named %r" % (
|
|
self.object_name,
|
|
base_manager_name,
|
|
)
|
|
)
|
|
|
|
manager = Manager()
|
|
manager.name = '_base_manager'
|
|
manager.model = self.model
|
|
manager.auto_created = True
|
|
return manager
|
|
|
|
@cached_property
|
|
def default_manager(self):
|
|
default_manager_name = self.default_manager_name
|
|
if not default_manager_name and not self.local_managers:
|
|
# Get the first parent's default_manager_name if there's one.
|
|
for parent in self.model.mro()[1:]:
|
|
if hasattr(parent, '_meta'):
|
|
default_manager_name = parent._meta.default_manager_name
|
|
break
|
|
|
|
if default_manager_name:
|
|
try:
|
|
return self.managers_map[default_manager_name]
|
|
except KeyError:
|
|
raise ValueError(
|
|
"%s has no manager named %r" % (
|
|
self.object_name,
|
|
default_manager_name,
|
|
)
|
|
)
|
|
|
|
if self.managers:
|
|
return self.managers[0]
|
|
|
|
@cached_property
|
|
def fields(self):
|
|
"""
|
|
Return a list of all forward fields on the model and its parents,
|
|
excluding ManyToManyFields.
|
|
|
|
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.
|
|
"""
|
|
# For legacy reasons, the fields property should only contain forward
|
|
# fields that are not private or with a m2m cardinality. Therefore we
|
|
# pass these three filters as filters to the generator.
|
|
# The third lambda is a longwinded way of checking f.related_model - we don't
|
|
# use that property directly because related_model is a cached property,
|
|
# and all the models may not have been loaded yet; we don't want to cache
|
|
# the string reference to the related_model.
|
|
def is_not_an_m2m_field(f):
|
|
return not (f.is_relation and f.many_to_many)
|
|
|
|
def is_not_a_generic_relation(f):
|
|
return not (f.is_relation and f.one_to_many)
|
|
|
|
def is_not_a_generic_foreign_key(f):
|
|
return not (
|
|
f.is_relation and f.many_to_one and not (hasattr(f.remote_field, 'model') and f.remote_field.model)
|
|
)
|
|
|
|
return make_immutable_fields_list(
|
|
"fields",
|
|
(f for f in self._get_fields(reverse=False)
|
|
if is_not_an_m2m_field(f) and is_not_a_generic_relation(f) and is_not_a_generic_foreign_key(f))
|
|
)
|
|
|
|
@cached_property
|
|
def concrete_fields(self):
|
|
"""
|
|
Return 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.
|
|
"""
|
|
return make_immutable_fields_list(
|
|
"concrete_fields", (f for f in self.fields if f.concrete)
|
|
)
|
|
|
|
@cached_property
|
|
def local_concrete_fields(self):
|
|
"""
|
|
Return 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.
|
|
"""
|
|
return make_immutable_fields_list(
|
|
"local_concrete_fields", (f for f in self.local_fields if f.concrete)
|
|
)
|
|
|
|
@cached_property
|
|
def many_to_many(self):
|
|
"""
|
|
Return 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(
|
|
"many_to_many",
|
|
(f for f in self._get_fields(reverse=False) if f.is_relation and f.many_to_many)
|
|
)
|
|
|
|
@cached_property
|
|
def related_objects(self):
|
|
"""
|
|
Return 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)
|
|
return make_immutable_fields_list(
|
|
"related_objects",
|
|
(obj for obj in all_related_fields if not obj.hidden or obj.field.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):
|
|
"""
|
|
Return a field instance given the name of a forward or reverse field.
|
|
"""
|
|
try:
|
|
# In order to avoid premature loading of the relation tree
|
|
# (expensive) we prefer checking if the field is a forward field.
|
|
return self._forward_fields_map[field_name]
|
|
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 '%s'. 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:
|
|
# 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 '%s'" % (self.object_name, field_name))
|
|
|
|
def get_base_chain(self, model):
|
|
"""
|
|
Return a list of parent classes leading to `model` (ordered from
|
|
closest to most distant ancestor). This has to handle the case where
|
|
`model` is a grandparent or even more distant relation.
|
|
"""
|
|
if not self.parents:
|
|
return []
|
|
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 []
|
|
|
|
def get_parent_list(self):
|
|
"""
|
|
Return 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):
|
|
"""
|
|
Return 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.
|
|
|
|
Return 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 get_path_to_parent(self, parent):
|
|
"""
|
|
Return a list of PathInfos containing the path from the current
|
|
model to the parent model, or an empty list if parent is not a
|
|
parent of the current model.
|
|
"""
|
|
if self.model is parent:
|
|
return []
|
|
# Skip the chain of proxy to the concrete proxied model.
|
|
proxied_model = self.concrete_model
|
|
path = []
|
|
opts = self
|
|
for int_model in self.get_base_chain(parent):
|
|
if int_model is proxied_model:
|
|
opts = int_model._meta
|
|
else:
|
|
final_field = opts.parents[int_model]
|
|
targets = (final_field.remote_field.get_related_field(),)
|
|
opts = int_model._meta
|
|
path.append(PathInfo(
|
|
from_opts=final_field.model._meta,
|
|
to_opts=opts,
|
|
target_fields=targets,
|
|
join_field=final_field,
|
|
m2m=False,
|
|
direct=True,
|
|
filtered_relation=None,
|
|
))
|
|
return path
|
|
|
|
def get_path_from_parent(self, parent):
|
|
"""
|
|
Return a list of PathInfos containing the path from the parent
|
|
model to the current model, or an empty list if parent is not a
|
|
parent of the current model.
|
|
"""
|
|
if self.model is parent:
|
|
return []
|
|
model = self.concrete_model
|
|
# Get a reversed base chain including both the current and parent
|
|
# models.
|
|
chain = model._meta.get_base_chain(parent)
|
|
chain.reverse()
|
|
chain.append(model)
|
|
# Construct a list of the PathInfos between models in chain.
|
|
path = []
|
|
for i, ancestor in enumerate(chain[:-1]):
|
|
child = chain[i + 1]
|
|
link = child._meta.get_ancestor_link(ancestor)
|
|
path.extend(link.reverse_path_infos)
|
|
return path
|
|
|
|
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:
|
|
opts = model._meta
|
|
# Abstract model's fields are copied to child models, hence we will
|
|
# see the fields from the child models.
|
|
if opts.abstract:
|
|
continue
|
|
fields_with_relations = (
|
|
f for f in opts._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, str):
|
|
remote_label = f.remote_field.model._meta.concrete_model._meta.label
|
|
related_objects_graph[remote_label].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.concrete_model._meta.label]
|
|
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.
|
|
if forward:
|
|
for cache_key in self.FORWARD_PROPERTIES:
|
|
if cache_key in self.__dict__:
|
|
delattr(self, cache_key)
|
|
if reverse and not self.abstract:
|
|
for cache_key in self.REVERSE_PROPERTIES:
|
|
if cache_key in self.__dict__:
|
|
delattr(self, cache_key)
|
|
self._get_fields_cache = {}
|
|
|
|
def get_fields(self, include_parents=True, include_hidden=False):
|
|
"""
|
|
Return a list of fields associated to the model. By default, include
|
|
forward and reverse fields, fields derived from inheritance, but not
|
|
hidden fields. The returned fields can be changed 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 = seen_models is None
|
|
if topmost_call:
|
|
seen_models = set()
|
|
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 not getattr(obj, 'parent_link', False) or obj.model == self.concrete_model:
|
|
fields.append(obj)
|
|
if reverse and not self.proxy:
|
|
# 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 += self.local_fields
|
|
fields += self.local_many_to_many
|
|
# Private 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 private 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 += self.private_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
|
|
|
|
@cached_property
|
|
def total_unique_constraints(self):
|
|
"""
|
|
Return a list of total unique constraints. Useful for determining set
|
|
of fields guaranteed to be unique for all rows.
|
|
"""
|
|
return [
|
|
constraint
|
|
for constraint in self.constraints
|
|
if (
|
|
isinstance(constraint, UniqueConstraint) and
|
|
constraint.condition is None and
|
|
not constraint.contains_expressions
|
|
)
|
|
]
|
|
|
|
@cached_property
|
|
def _property_names(self):
|
|
"""Return a set of the names of the properties defined on the model."""
|
|
names = []
|
|
for name in dir(self.model):
|
|
attr = inspect.getattr_static(self.model, name)
|
|
if isinstance(attr, property):
|
|
names.append(name)
|
|
return frozenset(names)
|
|
|
|
@cached_property
|
|
def db_returning_fields(self):
|
|
"""
|
|
Private API intended only to be used by Django itself.
|
|
Fields to be returned after a database insert.
|
|
"""
|
|
return [
|
|
field for field in self._get_fields(forward=True, reverse=False, include_parents=PROXY_PARENTS)
|
|
if getattr(field, 'db_returning', False)
|
|
]
|