532 lines
23 KiB
Python
532 lines
23 KiB
Python
import copy
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import types
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import sys
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import os
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from itertools import izip
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try:
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set
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except NameError:
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from sets import Set as set # Python 2.3 fallback.
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import django.db.models.manager # Imported to register signal handler.
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from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned, FieldError
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from django.db.models.fields import AutoField
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from django.db.models.fields.related import OneToOneRel, ManyToOneRel, OneToOneField
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from django.db.models.query import delete_objects, Q, CollectedObjects
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from django.db.models.options import Options
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from django.db import connection, transaction, DatabaseError
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from django.db.models import signals
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from django.db.models.loading import register_models, get_model
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from django.utils.functional import curry
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from django.utils.encoding import smart_str, force_unicode, smart_unicode
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from django.conf import settings
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class ModelBase(type):
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"""
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Metaclass for all models.
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"""
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def __new__(cls, name, bases, attrs):
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super_new = super(ModelBase, cls).__new__
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parents = [b for b in bases if isinstance(b, ModelBase)]
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if not parents:
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# If this isn't a subclass of Model, don't do anything special.
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return super_new(cls, name, bases, attrs)
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# Create the class.
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module = attrs.pop('__module__')
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new_class = super_new(cls, name, bases, {'__module__': module})
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attr_meta = attrs.pop('Meta', None)
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abstract = getattr(attr_meta, 'abstract', False)
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if not attr_meta:
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meta = getattr(new_class, 'Meta', None)
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else:
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meta = attr_meta
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base_meta = getattr(new_class, '_meta', None)
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if getattr(meta, 'app_label', None) is None:
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# Figure out the app_label by looking one level up.
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# For 'django.contrib.sites.models', this would be 'sites'.
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model_module = sys.modules[new_class.__module__]
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kwargs = {"app_label": model_module.__name__.split('.')[-2]}
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else:
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kwargs = {}
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new_class.add_to_class('_meta', Options(meta, **kwargs))
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if not abstract:
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new_class.add_to_class('DoesNotExist',
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subclass_exception('DoesNotExist', ObjectDoesNotExist, module))
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new_class.add_to_class('MultipleObjectsReturned',
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subclass_exception('MultipleObjectsReturned', MultipleObjectsReturned, module))
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if base_meta and not base_meta.abstract:
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# Non-abstract child classes inherit some attributes from their
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# non-abstract parent (unless an ABC comes before it in the
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# method resolution order).
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if not hasattr(meta, 'ordering'):
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new_class._meta.ordering = base_meta.ordering
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if not hasattr(meta, 'get_latest_by'):
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new_class._meta.get_latest_by = base_meta.get_latest_by
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if getattr(new_class, '_default_manager', None):
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new_class._default_manager = None
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# Bail out early if we have already created this class.
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m = get_model(new_class._meta.app_label, name, False)
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if m is not None:
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return m
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# Add all attributes to the class.
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for obj_name, obj in attrs.items():
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new_class.add_to_class(obj_name, obj)
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# Do the appropriate setup for any model parents.
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o2o_map = dict([(f.rel.to, f) for f in new_class._meta.local_fields
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if isinstance(f, OneToOneField)])
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for base in parents:
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if not hasattr(base, '_meta'):
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# Things without _meta aren't functional models, so they're
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# uninteresting parents.
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continue
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# All the fields of any type declared on this model
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new_fields = new_class._meta.local_fields + \
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new_class._meta.local_many_to_many + \
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new_class._meta.virtual_fields
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field_names = set([f.name for f in new_fields])
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if not base._meta.abstract:
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# Concrete classes...
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if base in o2o_map:
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field = o2o_map[base]
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field.primary_key = True
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new_class._meta.setup_pk(field)
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else:
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attr_name = '%s_ptr' % base._meta.module_name
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field = OneToOneField(base, name=attr_name,
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auto_created=True, parent_link=True)
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new_class.add_to_class(attr_name, field)
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new_class._meta.parents[base] = field
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else:
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# .. and abstract ones.
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# Check for clashes between locally declared fields and those
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# on the ABC.
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parent_fields = base._meta.local_fields + base._meta.local_many_to_many
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for field in parent_fields:
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if field.name in field_names:
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raise FieldError('Local field %r in class %r clashes '\
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'with field of similar name from '\
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'abstract base class %r' % \
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(field.name, name, base.__name__))
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new_class.add_to_class(field.name, copy.deepcopy(field))
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# Pass any non-abstract parent classes onto child.
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new_class._meta.parents.update(base._meta.parents)
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# Inherit managers from the abstract base classes.
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base_managers = base._meta.abstract_managers
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base_managers.sort()
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for _, mgr_name, manager in base_managers:
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val = getattr(new_class, mgr_name, None)
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if not val or val is manager:
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new_manager = manager._copy_to_model(new_class)
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new_class.add_to_class(mgr_name, new_manager)
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# Inherit virtual fields (like GenericForeignKey) from the parent class
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for field in base._meta.virtual_fields:
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if base._meta.abstract and field.name in field_names:
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raise FieldError('Local field %r in class %r clashes '\
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'with field of similar name from '\
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'abstract base class %r' % \
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(field.name, name, base.__name__))
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new_class.add_to_class(field.name, copy.deepcopy(field))
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if abstract:
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# Abstract base models can't be instantiated and don't appear in
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# the list of models for an app. We do the final setup for them a
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# little differently from normal models.
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attr_meta.abstract = False
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new_class.Meta = attr_meta
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return new_class
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new_class._prepare()
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register_models(new_class._meta.app_label, new_class)
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# Because of the way imports happen (recursively), we may or may not be
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# the first time this model tries to register with the framework. There
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# should only be one class for each model, so we always return the
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# registered version.
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return get_model(new_class._meta.app_label, name, False)
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def add_to_class(cls, name, value):
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if hasattr(value, 'contribute_to_class'):
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value.contribute_to_class(cls, name)
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else:
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setattr(cls, name, value)
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def _prepare(cls):
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"""
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Creates some methods once self._meta has been populated.
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"""
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opts = cls._meta
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opts._prepare(cls)
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if opts.order_with_respect_to:
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cls.get_next_in_order = curry(cls._get_next_or_previous_in_order, is_next=True)
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cls.get_previous_in_order = curry(cls._get_next_or_previous_in_order, is_next=False)
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setattr(opts.order_with_respect_to.rel.to, 'get_%s_order' % cls.__name__.lower(), curry(method_get_order, cls))
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setattr(opts.order_with_respect_to.rel.to, 'set_%s_order' % cls.__name__.lower(), curry(method_set_order, cls))
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# Give the class a docstring -- its definition.
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if cls.__doc__ is None:
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cls.__doc__ = "%s(%s)" % (cls.__name__, ", ".join([f.attname for f in opts.fields]))
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if hasattr(cls, 'get_absolute_url'):
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cls.get_absolute_url = curry(get_absolute_url, opts, cls.get_absolute_url)
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signals.class_prepared.send(sender=cls)
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class Model(object):
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__metaclass__ = ModelBase
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def __init__(self, *args, **kwargs):
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signals.pre_init.send(sender=self.__class__, args=args, kwargs=kwargs)
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# There is a rather weird disparity here; if kwargs, it's set, then args
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# overrides it. It should be one or the other; don't duplicate the work
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# The reason for the kwargs check is that standard iterator passes in by
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# args, and instantiation for iteration is 33% faster.
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args_len = len(args)
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if args_len > len(self._meta.fields):
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# Daft, but matches old exception sans the err msg.
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raise IndexError("Number of args exceeds number of fields")
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fields_iter = iter(self._meta.fields)
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if not kwargs:
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# The ordering of the izip calls matter - izip throws StopIteration
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# when an iter throws it. So if the first iter throws it, the second
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# is *not* consumed. We rely on this, so don't change the order
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# without changing the logic.
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for val, field in izip(args, fields_iter):
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setattr(self, field.attname, val)
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else:
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# Slower, kwargs-ready version.
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for val, field in izip(args, fields_iter):
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setattr(self, field.attname, val)
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kwargs.pop(field.name, None)
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# Maintain compatibility with existing calls.
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if isinstance(field.rel, ManyToOneRel):
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kwargs.pop(field.attname, None)
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# Now we're left with the unprocessed fields that *must* come from
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# keywords, or default.
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for field in fields_iter:
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rel_obj = None
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if kwargs:
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if isinstance(field.rel, ManyToOneRel):
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try:
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# Assume object instance was passed in.
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rel_obj = kwargs.pop(field.name)
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except KeyError:
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try:
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# Object instance wasn't passed in -- must be an ID.
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val = kwargs.pop(field.attname)
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except KeyError:
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val = field.get_default()
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else:
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# Object instance was passed in. Special case: You can
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# pass in "None" for related objects if it's allowed.
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if rel_obj is None and field.null:
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val = None
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else:
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val = kwargs.pop(field.attname, field.get_default())
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else:
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val = field.get_default()
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# If we got passed a related instance, set it using the field.name
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# instead of field.attname (e.g. "user" instead of "user_id") so
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# that the object gets properly cached (and type checked) by the
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# RelatedObjectDescriptor.
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if rel_obj:
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setattr(self, field.name, rel_obj)
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else:
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setattr(self, field.attname, val)
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if kwargs:
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for prop in kwargs.keys():
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try:
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if isinstance(getattr(self.__class__, prop), property):
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setattr(self, prop, kwargs.pop(prop))
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except AttributeError:
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pass
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if kwargs:
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raise TypeError, "'%s' is an invalid keyword argument for this function" % kwargs.keys()[0]
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signals.post_init.send(sender=self.__class__, instance=self)
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def __repr__(self):
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try:
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u = unicode(self)
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except (UnicodeEncodeError, UnicodeDecodeError):
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u = '[Bad Unicode data]'
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return smart_str(u'<%s: %s>' % (self.__class__.__name__, u))
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def __str__(self):
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if hasattr(self, '__unicode__'):
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return force_unicode(self).encode('utf-8')
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return '%s object' % self.__class__.__name__
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def __eq__(self, other):
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return isinstance(other, self.__class__) and self._get_pk_val() == other._get_pk_val()
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def __ne__(self, other):
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return not self.__eq__(other)
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def __hash__(self):
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return hash(self._get_pk_val())
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def _get_pk_val(self, meta=None):
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if not meta:
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meta = self._meta
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return getattr(self, meta.pk.attname)
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def _set_pk_val(self, value):
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return setattr(self, self._meta.pk.attname, value)
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pk = property(_get_pk_val, _set_pk_val)
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def save(self, force_insert=False, force_update=False):
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"""
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Saves the current instance. Override this in a subclass if you want to
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control the saving process.
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The 'force_insert' and 'force_update' parameters can be used to insist
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that the "save" must be an SQL insert or update (or equivalent for
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non-SQL backends), respectively. Normally, they should not be set.
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"""
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if force_insert and force_update:
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raise ValueError("Cannot force both insert and updating in "
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"model saving.")
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self.save_base(force_insert=force_insert, force_update=force_update)
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save.alters_data = True
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def save_base(self, raw=False, cls=None, force_insert=False,
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force_update=False):
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"""
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Does the heavy-lifting involved in saving. Subclasses shouldn't need to
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override this method. It's separate from save() in order to hide the
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need for overrides of save() to pass around internal-only parameters
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('raw' and 'cls').
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"""
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assert not (force_insert and force_update)
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if not cls:
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cls = self.__class__
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meta = self._meta
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signal = True
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signals.pre_save.send(sender=self.__class__, instance=self, raw=raw)
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else:
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meta = cls._meta
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signal = False
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# If we are in a raw save, save the object exactly as presented.
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# That means that we don't try to be smart about saving attributes
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# that might have come from the parent class - we just save the
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# attributes we have been given to the class we have been given.
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if not raw:
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for parent, field in meta.parents.items():
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# At this point, parent's primary key field may be unknown
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# (for example, from administration form which doesn't fill
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# this field). If so, fill it.
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if getattr(self, parent._meta.pk.attname) is None and getattr(self, field.attname) is not None:
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setattr(self, parent._meta.pk.attname, getattr(self, field.attname))
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self.save_base(raw, parent)
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setattr(self, field.attname, self._get_pk_val(parent._meta))
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non_pks = [f for f in meta.local_fields if not f.primary_key]
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# First, try an UPDATE. If that doesn't update anything, do an INSERT.
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pk_val = self._get_pk_val(meta)
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pk_set = pk_val is not None
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record_exists = True
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manager = cls._default_manager
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if pk_set:
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# Determine whether a record with the primary key already exists.
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if (force_update or (not force_insert and
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manager.filter(pk=pk_val).extra(select={'a': 1}).values('a').order_by())):
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# It does already exist, so do an UPDATE.
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if force_update or non_pks:
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values = [(f, None, f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, False))) for f in non_pks]
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rows = manager.filter(pk=pk_val)._update(values)
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if force_update and not rows:
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raise DatabaseError("Forced update did not affect any rows.")
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else:
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record_exists = False
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if not pk_set or not record_exists:
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if not pk_set:
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if force_update:
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raise ValueError("Cannot force an update in save() with no primary key.")
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values = [(f, f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, True))) for f in meta.local_fields if not isinstance(f, AutoField)]
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else:
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values = [(f, f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, True))) for f in meta.local_fields]
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if meta.order_with_respect_to:
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field = meta.order_with_respect_to
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values.append((meta.get_field_by_name('_order')[0], manager.filter(**{field.name: getattr(self, field.attname)}).count()))
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record_exists = False
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update_pk = bool(meta.has_auto_field and not pk_set)
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if values:
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# Create a new record.
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result = manager._insert(values, return_id=update_pk)
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else:
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# Create a new record with defaults for everything.
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result = manager._insert([(meta.pk, connection.ops.pk_default_value())], return_id=update_pk, raw_values=True)
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if update_pk:
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setattr(self, meta.pk.attname, result)
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transaction.commit_unless_managed()
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if signal:
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signals.post_save.send(sender=self.__class__, instance=self,
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created=(not record_exists), raw=raw)
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save_base.alters_data = True
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def _collect_sub_objects(self, seen_objs, parent=None, nullable=False):
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"""
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Recursively populates seen_objs with all objects related to this
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object.
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When done, seen_objs.items() will be in the format:
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[(model_class, {pk_val: obj, pk_val: obj, ...}),
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(model_class, {pk_val: obj, pk_val: obj, ...}), ...]
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"""
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pk_val = self._get_pk_val()
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if seen_objs.add(self.__class__, pk_val, self, parent, nullable):
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return
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for related in self._meta.get_all_related_objects():
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rel_opts_name = related.get_accessor_name()
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if isinstance(related.field.rel, OneToOneRel):
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try:
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sub_obj = getattr(self, rel_opts_name)
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except ObjectDoesNotExist:
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pass
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else:
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sub_obj._collect_sub_objects(seen_objs, self.__class__, related.field.null)
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else:
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for sub_obj in getattr(self, rel_opts_name).all():
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sub_obj._collect_sub_objects(seen_objs, self.__class__, related.field.null)
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# Handle any ancestors (for the model-inheritance case). We do this by
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# traversing to the most remote parent classes -- those with no parents
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# themselves -- and then adding those instances to the collection. That
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# will include all the child instances down to "self".
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parent_stack = self._meta.parents.values()
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while parent_stack:
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link = parent_stack.pop()
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parent_obj = getattr(self, link.name)
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if parent_obj._meta.parents:
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parent_stack.extend(parent_obj._meta.parents.values())
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continue
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# At this point, parent_obj is base class (no ancestor models). So
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# delete it and all its descendents.
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parent_obj._collect_sub_objects(seen_objs)
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def delete(self):
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assert self._get_pk_val() is not None, "%s object can't be deleted because its %s attribute is set to None." % (self._meta.object_name, self._meta.pk.attname)
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# Find all the objects than need to be deleted.
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seen_objs = CollectedObjects()
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self._collect_sub_objects(seen_objs)
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# Actually delete the objects.
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delete_objects(seen_objs)
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delete.alters_data = True
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def _get_FIELD_display(self, field):
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value = getattr(self, field.attname)
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return force_unicode(dict(field.flatchoices).get(value, value), strings_only=True)
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def _get_next_or_previous_by_FIELD(self, field, is_next, **kwargs):
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op = is_next and 'gt' or 'lt'
|
|
order = not is_next and '-' or ''
|
|
param = smart_str(getattr(self, field.attname))
|
|
q = Q(**{'%s__%s' % (field.name, op): param})
|
|
q = q|Q(**{field.name: param, 'pk__%s' % op: self.pk})
|
|
qs = self.__class__._default_manager.filter(**kwargs).filter(q).order_by('%s%s' % (order, field.name), '%spk' % order)
|
|
try:
|
|
return qs[0]
|
|
except IndexError:
|
|
raise self.DoesNotExist, "%s matching query does not exist." % self.__class__._meta.object_name
|
|
|
|
def _get_next_or_previous_in_order(self, is_next):
|
|
cachename = "__%s_order_cache" % is_next
|
|
if not hasattr(self, cachename):
|
|
qn = connection.ops.quote_name
|
|
op = is_next and '>' or '<'
|
|
order = not is_next and '-_order' or '_order'
|
|
order_field = self._meta.order_with_respect_to
|
|
# FIXME: When querysets support nested queries, this can be turned
|
|
# into a pure queryset operation.
|
|
where = ['%s %s (SELECT %s FROM %s WHERE %s=%%s)' % \
|
|
(qn('_order'), op, qn('_order'),
|
|
qn(self._meta.db_table), qn(self._meta.pk.column))]
|
|
params = [self.pk]
|
|
obj = self._default_manager.filter(**{order_field.name: getattr(self, order_field.attname)}).extra(where=where, params=params).order_by(order)[:1].get()
|
|
setattr(self, cachename, obj)
|
|
return getattr(self, cachename)
|
|
|
|
|
|
|
|
############################################
|
|
# HELPER FUNCTIONS (CURRIED MODEL METHODS) #
|
|
############################################
|
|
|
|
# ORDERING METHODS #########################
|
|
|
|
def method_set_order(ordered_obj, self, id_list):
|
|
rel_val = getattr(self, ordered_obj._meta.order_with_respect_to.rel.field_name)
|
|
order_name = ordered_obj._meta.order_with_respect_to.name
|
|
# FIXME: It would be nice if there was an "update many" version of update
|
|
# for situations like this.
|
|
for i, j in enumerate(id_list):
|
|
ordered_obj.objects.filter(**{'pk': j, order_name: rel_val}).update(_order=i)
|
|
transaction.commit_unless_managed()
|
|
|
|
|
|
def method_get_order(ordered_obj, self):
|
|
rel_val = getattr(self, ordered_obj._meta.order_with_respect_to.rel.field_name)
|
|
order_name = ordered_obj._meta.order_with_respect_to.name
|
|
pk_name = ordered_obj._meta.pk.name
|
|
return [r[pk_name] for r in
|
|
ordered_obj.objects.filter(**{order_name: rel_val}).values(pk_name)]
|
|
|
|
|
|
##############################################
|
|
# HELPER FUNCTIONS (CURRIED MODEL FUNCTIONS) #
|
|
##############################################
|
|
|
|
def get_absolute_url(opts, func, self, *args, **kwargs):
|
|
return settings.ABSOLUTE_URL_OVERRIDES.get('%s.%s' % (opts.app_label, opts.module_name), func)(self, *args, **kwargs)
|
|
|
|
|
|
########
|
|
# MISC #
|
|
########
|
|
|
|
class Empty(object):
|
|
pass
|
|
|
|
if sys.version_info < (2, 5):
|
|
# Prior to Python 2.5, Exception was an old-style class
|
|
def subclass_exception(name, parent, unused):
|
|
return types.ClassType(name, (parent,), {})
|
|
else:
|
|
def subclass_exception(name, parent, module):
|
|
return type(name, (parent,), {'__module__': module})
|