656 lines
29 KiB
Python
656 lines
29 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, FieldDoesNotExist
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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
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from django.db.models.query_utils import CollectedObjects, DeferredAttribute
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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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is_proxy = new_class._meta.proxy
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if getattr(new_class, '_default_manager', None):
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if not is_proxy:
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# Multi-table inheritance doesn't inherit default manager from
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# parents.
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new_class._default_manager = None
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new_class._base_manager = None
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else:
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# Proxy classes do inherit parent's default manager, if none is
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# set explicitly.
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new_class._default_manager = new_class._default_manager._copy_to_model(new_class)
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new_class._base_manager = new_class._base_manager._copy_to_model(new_class)
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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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# 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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# Basic setup for proxy models.
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if is_proxy:
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base = None
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for parent in [cls for cls in parents if hasattr(cls, '_meta')]:
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if parent._meta.abstract:
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if parent._meta.fields:
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raise TypeError("Abstract base class containing model fields not permitted for proxy model '%s'." % name)
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else:
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continue
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if base is not None:
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raise TypeError("Proxy model '%s' has more than one non-abstract model base class." % name)
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else:
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base = parent
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if base is None:
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raise TypeError("Proxy model '%s' has no non-abstract model base class." % name)
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if (new_class._meta.local_fields or
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new_class._meta.local_many_to_many):
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raise FieldError("Proxy model '%s' contains model fields."
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% name)
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while base._meta.proxy:
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base = base._meta.proxy_for_model
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new_class._meta.setup_proxy(base)
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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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original_base = base
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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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parent_fields = base._meta.local_fields + base._meta.local_many_to_many
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# Check for clashes between locally declared fields and those
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# on the base classes (we cannot handle shadowed fields at the
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# moment).
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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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'base class %r' %
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(field.name, name, base.__name__))
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if not base._meta.abstract:
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# Concrete classes...
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while base._meta.proxy:
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# Skip over a proxy class to the "real" base it proxies.
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base = base._meta.proxy_for_model
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if base in o2o_map:
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field = o2o_map[base]
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elif not is_proxy:
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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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else:
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field = None
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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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for field in parent_fields:
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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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new_class.copy_managers(base._meta.abstract_managers)
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# Proxy models inherit the non-abstract managers from their base,
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# unless they have redefined any of them.
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if is_proxy:
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new_class.copy_managers(original_base._meta.concrete_managers)
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# Inherit virtual fields (like GenericForeignKey) from the parent
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# 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 copy_managers(cls, base_managers):
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# This is in-place sorting of an Options attribute, but that's fine.
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base_managers.sort()
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for _, mgr_name, manager in base_managers:
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val = getattr(cls, mgr_name, None)
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if not val or val is manager:
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new_manager = manager._copy_to_model(cls)
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cls.add_to_class(mgr_name, new_manager)
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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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_deferred = False
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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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is_related_object = False
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# This slightly odd construct is so that we can access any
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# data-descriptor object (DeferredAttribute) without triggering its
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# __get__ method.
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if (field.attname not in kwargs and
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isinstance(self.__class__.__dict__.get(field.attname), DeferredAttribute)):
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# This field will be populated on request.
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continue
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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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is_related_object = True
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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 is_related_object:
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# If we are passed a related instance, set it using the
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# field.name instead of field.attname (e.g. "user" instead of
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# "user_id") so that the object gets properly cached (and type
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# checked) by the RelatedObjectDescriptor.
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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 __reduce__(self):
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"""
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Provide pickling support. Normally, this just dispatches to Python's
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standard handling. However, for models with deferred field loading, we
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need to do things manually, as they're dynamically created classes and
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only module-level classes can be pickled by the default path.
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"""
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data = self.__dict__
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if not self._deferred:
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return (self.__class__, (), data)
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defers = []
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pk_val = None
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for field in self._meta.fields:
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if isinstance(self.__class__.__dict__.get(field.attname),
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DeferredAttribute):
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defers.append(field.attname)
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if pk_val is None:
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# The pk_val and model values are the same for all
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# DeferredAttribute classes, so we only need to do this
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# once.
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obj = self.__class__.__dict__[field.attname]
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model = obj.model_ref()
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return (model_unpickle, (model, defers), data)
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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 serializable_value(self, field_name):
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"""
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Returns the value of the field name for this instance. If the field is
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a foreign key, returns the id value, instead of the object. If there's
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no Field object with this name on the model, the model attribute's
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value is returned directly.
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Used to serialize a field's value (in the serializer, or form output,
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for example). Normally, you would just access the attribute directly
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and not use this method.
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"""
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try:
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field = self._meta.get_field_by_name(field_name)[0]
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except FieldDoesNotExist:
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return getattr(self, field_name)
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return getattr(self, field.attname)
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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 field and 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(cls=parent)
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if field:
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setattr(self, field.attname, self._get_pk_val(parent._meta))
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if meta.proxy:
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return
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if not meta.proxy:
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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._base_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, (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:
|
|
record_exists = False
|
|
if not pk_set or not record_exists:
|
|
if not pk_set:
|
|
if force_update:
|
|
raise ValueError("Cannot force an update in save() with no primary key.")
|
|
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)]
|
|
else:
|
|
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 meta.order_with_respect_to:
|
|
field = meta.order_with_respect_to
|
|
values.append((meta.get_field_by_name('_order')[0], manager.filter(**{field.name: getattr(self, field.attname)}).count()))
|
|
record_exists = False
|
|
|
|
update_pk = bool(meta.has_auto_field and not pk_set)
|
|
if values:
|
|
# Create a new record.
|
|
result = manager._insert(values, return_id=update_pk)
|
|
else:
|
|
# Create a new record with defaults for everything.
|
|
result = manager._insert([(meta.pk, connection.ops.pk_default_value())], return_id=update_pk, raw_values=True)
|
|
|
|
if update_pk:
|
|
setattr(self, meta.pk.attname, result)
|
|
transaction.commit_unless_managed()
|
|
|
|
if signal:
|
|
signals.post_save.send(sender=self.__class__, instance=self,
|
|
created=(not record_exists), raw=raw)
|
|
|
|
save_base.alters_data = True
|
|
|
|
def _collect_sub_objects(self, seen_objs, parent=None, nullable=False):
|
|
"""
|
|
Recursively populates seen_objs with all objects related to this
|
|
object.
|
|
|
|
When done, seen_objs.items() will be in the format:
|
|
[(model_class, {pk_val: obj, pk_val: obj, ...}),
|
|
(model_class, {pk_val: obj, pk_val: obj, ...}), ...]
|
|
"""
|
|
pk_val = self._get_pk_val()
|
|
if seen_objs.add(self.__class__, pk_val, self, parent, nullable):
|
|
return
|
|
|
|
for related in self._meta.get_all_related_objects():
|
|
rel_opts_name = related.get_accessor_name()
|
|
if isinstance(related.field.rel, OneToOneRel):
|
|
try:
|
|
sub_obj = getattr(self, rel_opts_name)
|
|
except ObjectDoesNotExist:
|
|
pass
|
|
else:
|
|
sub_obj._collect_sub_objects(seen_objs, self.__class__, related.field.null)
|
|
else:
|
|
# To make sure we can access all elements, we can't use the
|
|
# normal manager on the related object. So we work directly
|
|
# with the descriptor object.
|
|
for cls in self.__class__.mro():
|
|
if rel_opts_name in cls.__dict__:
|
|
rel_descriptor = cls.__dict__[rel_opts_name]
|
|
break
|
|
else:
|
|
raise AssertionError("Should never get here.")
|
|
delete_qs = rel_descriptor.delete_manager(self).all()
|
|
for sub_obj in delete_qs:
|
|
sub_obj._collect_sub_objects(seen_objs, self.__class__, related.field.null)
|
|
|
|
# Handle any ancestors (for the model-inheritance case). We do this by
|
|
# traversing to the most remote parent classes -- those with no parents
|
|
# themselves -- and then adding those instances to the collection. That
|
|
# will include all the child instances down to "self".
|
|
parent_stack = self._meta.parents.values()
|
|
while parent_stack:
|
|
link = parent_stack.pop()
|
|
parent_obj = getattr(self, link.name)
|
|
if parent_obj._meta.parents:
|
|
parent_stack.extend(parent_obj._meta.parents.values())
|
|
continue
|
|
# At this point, parent_obj is base class (no ancestor models). So
|
|
# delete it and all its descendents.
|
|
parent_obj._collect_sub_objects(seen_objs)
|
|
|
|
def delete(self):
|
|
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)
|
|
|
|
# Find all the objects than need to be deleted.
|
|
seen_objs = CollectedObjects()
|
|
self._collect_sub_objects(seen_objs)
|
|
|
|
# Actually delete the objects.
|
|
delete_objects(seen_objs)
|
|
|
|
delete.alters_data = True
|
|
|
|
def _get_FIELD_display(self, field):
|
|
value = getattr(self, field.attname)
|
|
return force_unicode(dict(field.flatchoices).get(value, value), strings_only=True)
|
|
|
|
def _get_next_or_previous_by_FIELD(self, field, is_next, **kwargs):
|
|
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)
|
|
|
|
def prepare_database_save(self, unused):
|
|
return self.pk
|
|
|
|
|
|
############################################
|
|
# 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
|
|
|
|
def model_unpickle(model, attrs):
|
|
"""
|
|
Used to unpickle Model subclasses with deferred fields.
|
|
"""
|
|
from django.db.models.query_utils import deferred_class_factory
|
|
cls = deferred_class_factory(model, attrs)
|
|
return cls.__new__(cls)
|
|
model_unpickle.__safe_for_unpickle__ = True
|
|
|
|
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})
|