| import copy |
| import types |
| import sys |
| import os |
| from itertools import izip |
| try: |
| set |
| except NameError: |
| from sets import Set as set # Python 2.3 fallback. |
| |
| import django.db.models.manipulators # Imported to register signal handler. |
| import django.db.models.manager # Ditto. |
| from django.core import validators |
| from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned, FieldError |
| from django.db.models.fields import AutoField |
| from django.db.models.fields.related import OneToOneRel, ManyToOneRel, OneToOneField |
| from django.db.models.query import delete_objects, Q, CollectedObjects |
| from django.db.models.options import Options |
| from django.db import connection, transaction, DatabaseError |
| from django.db.models import signals |
| from django.db.models.loading import register_models, get_model |
| from django.utils.functional import curry |
| from django.utils.encoding import smart_str, force_unicode, smart_unicode |
| from django.core.files.move import file_move_safe |
| from django.core.files import locks |
| from django.conf import settings |
| |
| |
| class ModelBase(type): |
| """ |
| Metaclass for all models. |
| """ |
| def __new__(cls, name, bases, attrs): |
| super_new = super(ModelBase, cls).__new__ |
| parents = [b for b in bases if isinstance(b, ModelBase)] |
| if not parents: |
| # If this isn't a subclass of Model, don't do anything special. |
| return super_new(cls, name, bases, attrs) |
| |
| # Create the class. |
| module = attrs.pop('__module__') |
| new_class = super_new(cls, name, bases, {'__module__': module}) |
| attr_meta = attrs.pop('Meta', None) |
| abstract = getattr(attr_meta, 'abstract', False) |
| if not attr_meta: |
| meta = getattr(new_class, 'Meta', None) |
| else: |
| meta = attr_meta |
| base_meta = getattr(new_class, '_meta', None) |
| |
| if getattr(meta, 'app_label', None) is None: |
| # Figure out the app_label by looking one level up. |
| # For 'django.contrib.sites.models', this would be 'sites'. |
| model_module = sys.modules[new_class.__module__] |
| kwargs = {"app_label": model_module.__name__.split('.')[-2]} |
| else: |
| kwargs = {} |
| |
| new_class.add_to_class('_meta', Options(meta, **kwargs)) |
| if not abstract: |
| new_class.add_to_class('DoesNotExist', |
| subclass_exception('DoesNotExist', ObjectDoesNotExist, module)) |
| new_class.add_to_class('MultipleObjectsReturned', |
| subclass_exception('MultipleObjectsReturned', MultipleObjectsReturned, module)) |
| if base_meta and not base_meta.abstract: |
| # Non-abstract child classes inherit some attributes from their |
| # non-abstract parent (unless an ABC comes before it in the |
| # method resolution order). |
| if not hasattr(meta, 'ordering'): |
| new_class._meta.ordering = base_meta.ordering |
| if not hasattr(meta, 'get_latest_by'): |
| new_class._meta.get_latest_by = base_meta.get_latest_by |
| |
| old_default_mgr = None |
| if getattr(new_class, '_default_manager', None): |
| # We have a parent who set the default manager. |
| if new_class._default_manager.model._meta.abstract: |
| old_default_mgr = new_class._default_manager |
| new_class._default_manager = None |
| |
| # Bail out early if we have already created this class. |
| m = get_model(new_class._meta.app_label, name, False) |
| if m is not None: |
| return m |
| |
| # Add all attributes to the class. |
| for obj_name, obj in attrs.items(): |
| new_class.add_to_class(obj_name, obj) |
| |
| # Do the appropriate setup for any model parents. |
| o2o_map = dict([(f.rel.to, f) for f in new_class._meta.local_fields |
| if isinstance(f, OneToOneField)]) |
| for base in parents: |
| if not hasattr(base, '_meta'): |
| # Things without _meta aren't functional models, so they're |
| # uninteresting parents. |
| continue |
| if not base._meta.abstract: |
| if base in o2o_map: |
| field = o2o_map[base] |
| field.primary_key = True |
| new_class._meta.setup_pk(field) |
| else: |
| attr_name = '%s_ptr' % base._meta.module_name |
| field = OneToOneField(base, name=attr_name, |
| auto_created=True, parent_link=True) |
| new_class.add_to_class(attr_name, field) |
| new_class._meta.parents[base] = field |
| else: |
| # The abstract base class case. |
| names = set([f.name for f in new_class._meta.local_fields + new_class._meta.many_to_many]) |
| for field in base._meta.local_fields + base._meta.local_many_to_many: |
| if field.name in names: |
| raise FieldError('Local field %r in class %r clashes with field of similar name from abstract base class %r' |
| % (field.name, name, base.__name__)) |
| new_class.add_to_class(field.name, copy.deepcopy(field)) |
| |
| if abstract: |
| # Abstract base models can't be instantiated and don't appear in |
| # the list of models for an app. We do the final setup for them a |
| # little differently from normal models. |
| attr_meta.abstract = False |
| new_class.Meta = attr_meta |
| return new_class |
| |
| if old_default_mgr and not new_class._default_manager: |
| new_class._default_manager = old_default_mgr._copy_to_model(new_class) |
| new_class._prepare() |
| register_models(new_class._meta.app_label, new_class) |
| |
| # Because of the way imports happen (recursively), we may or may not be |
| # the first time this model tries to register with the framework. There |
| # should only be one class for each model, so we always return the |
| # registered version. |
| return get_model(new_class._meta.app_label, name, False) |
| |
| def add_to_class(cls, name, value): |
| if hasattr(value, 'contribute_to_class'): |
| value.contribute_to_class(cls, name) |
| else: |
| setattr(cls, name, value) |
| |
| def _prepare(cls): |
| """ |
| Creates some methods once self._meta has been populated. |
| """ |
| opts = cls._meta |
| opts._prepare(cls) |
| |
| if opts.order_with_respect_to: |
| cls.get_next_in_order = curry(cls._get_next_or_previous_in_order, is_next=True) |
| cls.get_previous_in_order = curry(cls._get_next_or_previous_in_order, is_next=False) |
| setattr(opts.order_with_respect_to.rel.to, 'get_%s_order' % cls.__name__.lower(), curry(method_get_order, cls)) |
| setattr(opts.order_with_respect_to.rel.to, 'set_%s_order' % cls.__name__.lower(), curry(method_set_order, cls)) |
| |
| # Give the class a docstring -- its definition. |
| if cls.__doc__ is None: |
| cls.__doc__ = "%s(%s)" % (cls.__name__, ", ".join([f.attname for f in opts.fields])) |
| |
| if hasattr(cls, 'get_absolute_url'): |
| cls.get_absolute_url = curry(get_absolute_url, opts, cls.get_absolute_url) |
| |
| signals.class_prepared.send(sender=cls) |
| |
| |
| class Model(object): |
| __metaclass__ = ModelBase |
| |
| def __init__(self, *args, **kwargs): |
| signals.pre_init.send(sender=self.__class__, args=args, kwargs=kwargs) |
| |
| # There is a rather weird disparity here; if kwargs, it's set, then args |
| # overrides it. It should be one or the other; don't duplicate the work |
| # The reason for the kwargs check is that standard iterator passes in by |
| # args, and instantiation for iteration is 33% faster. |
| args_len = len(args) |
| if args_len > len(self._meta.fields): |
| # Daft, but matches old exception sans the err msg. |
| raise IndexError("Number of args exceeds number of fields") |
| |
| fields_iter = iter(self._meta.fields) |
| if not kwargs: |
| # The ordering of the izip calls matter - izip throws StopIteration |
| # when an iter throws it. So if the first iter throws it, the second |
| # is *not* consumed. We rely on this, so don't change the order |
| # without changing the logic. |
| for val, field in izip(args, fields_iter): |
| setattr(self, field.attname, val) |
| else: |
| # Slower, kwargs-ready version. |
| for val, field in izip(args, fields_iter): |
| setattr(self, field.attname, val) |
| kwargs.pop(field.name, None) |
| # Maintain compatibility with existing calls. |
| if isinstance(field.rel, ManyToOneRel): |
| kwargs.pop(field.attname, None) |
| |
| # Now we're left with the unprocessed fields that *must* come from |
| # keywords, or default. |
| |
| for field in fields_iter: |
| rel_obj = None |
| if kwargs: |
| if isinstance(field.rel, ManyToOneRel): |
| try: |
| # Assume object instance was passed in. |
| rel_obj = kwargs.pop(field.name) |
| except KeyError: |
| try: |
| # Object instance wasn't passed in -- must be an ID. |
| val = kwargs.pop(field.attname) |
| except KeyError: |
| val = field.get_default() |
| else: |
| # Object instance was passed in. Special case: You can |
| # pass in "None" for related objects if it's allowed. |
| if rel_obj is None and field.null: |
| val = None |
| else: |
| val = kwargs.pop(field.attname, field.get_default()) |
| else: |
| val = field.get_default() |
| # If we got passed a related instance, set it using the field.name |
| # instead of field.attname (e.g. "user" instead of "user_id") so |
| # that the object gets properly cached (and type checked) by the |
| # RelatedObjectDescriptor. |
| if rel_obj: |
| setattr(self, field.name, rel_obj) |
| else: |
| setattr(self, field.attname, val) |
| |
| if kwargs: |
| for prop in kwargs.keys(): |
| try: |
| if isinstance(getattr(self.__class__, prop), property): |
| setattr(self, prop, kwargs.pop(prop)) |
| except AttributeError: |
| pass |
| if kwargs: |
| raise TypeError, "'%s' is an invalid keyword argument for this function" % kwargs.keys()[0] |
| signals.post_init.send(sender=self.__class__, instance=self) |
| |
| def __repr__(self): |
| return smart_str(u'<%s: %s>' % (self.__class__.__name__, unicode(self))) |
| |
| def __str__(self): |
| if hasattr(self, '__unicode__'): |
| return force_unicode(self).encode('utf-8') |
| return '%s object' % self.__class__.__name__ |
| |
| def __eq__(self, other): |
| return isinstance(other, self.__class__) and self._get_pk_val() == other._get_pk_val() |
| |
| def __ne__(self, other): |
| return not self.__eq__(other) |
| |
| def __hash__(self): |
| return hash(self._get_pk_val()) |
| |
| def _get_pk_val(self, meta=None): |
| if not meta: |
| meta = self._meta |
| return getattr(self, meta.pk.attname) |
| |
| def _set_pk_val(self, value): |
| return setattr(self, self._meta.pk.attname, value) |
| |
| pk = property(_get_pk_val, _set_pk_val) |
| |
| def save(self, force_insert=False, force_update=False): |
| """ |
| Saves the current instance. Override this in a subclass if you want to |
| control the saving process. |
| |
| The 'force_insert' and 'force_update' parameters can be used to insist |
| that the "save" must be an SQL insert or update (or equivalent for |
| non-SQL backends), respectively. Normally, they should not be set. |
| """ |
| if force_insert and force_update: |
| raise ValueError("Cannot force both insert and updating in " |
| "model saving.") |
| self.save_base(force_insert=force_insert, force_update=force_update) |
| |
| save.alters_data = True |
| |
| def save_base(self, raw=False, cls=None, force_insert=False, |
| force_update=False): |
| """ |
| Does the heavy-lifting involved in saving. Subclasses shouldn't need to |
| override this method. It's separate from save() in order to hide the |
| need for overrides of save() to pass around internal-only parameters |
| ('raw' and 'cls'). |
| """ |
| assert not (force_insert and force_update) |
| if not cls: |
| cls = self.__class__ |
| meta = self._meta |
| signal = True |
| signals.pre_save.send(sender=self.__class__, instance=self, raw=raw) |
| else: |
| meta = cls._meta |
| signal = False |
| |
| # If we are in a raw save, save the object exactly as presented. |
| # That means that we don't try to be smart about saving attributes |
| # that might have come from the parent class - we just save the |
| # attributes we have been given to the class we have been given. |
| if not raw: |
| for parent, field in meta.parents.items(): |
| # At this point, parent's primary key field may be unknown |
| # (for example, from administration form which doesn't fill |
| # this field). If so, fill it. |
| if getattr(self, parent._meta.pk.attname) is None and getattr(self, field.attname) is not None: |
| setattr(self, parent._meta.pk.attname, getattr(self, field.attname)) |
| |
| self.save_base(raw, parent) |
| setattr(self, field.attname, self._get_pk_val(parent._meta)) |
| |
| non_pks = [f for f in meta.local_fields if not f.primary_key] |
| |
| # First, try an UPDATE. If that doesn't update anything, do an INSERT. |
| pk_val = self._get_pk_val(meta) |
| # Note: the comparison with '' is required for compatibility with |
| # oldforms-style model creation. |
| pk_set = pk_val is not None and smart_unicode(pk_val) != u'' |
| record_exists = True |
| manager = cls._default_manager |
| if pk_set: |
| # Determine whether a record with the primary key already exists. |
| if (force_update or (not force_insert and |
| manager.filter(pk=pk_val).extra(select={'a': 1}).values('a').order_by())): |
| # It does already exist, so do an UPDATE. |
| if force_update or non_pks: |
| 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] |
| rows = manager.filter(pk=pk_val)._update(values) |
| if force_update and not rows: |
| raise DatabaseError("Forced update did not affect any rows.") |
| 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: |
| for sub_obj in getattr(self, rel_opts_name).all(): |
| 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) |
| |
| |
| |
| ############################################ |
| # 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}) |
