from __future__ import unicode_literals from bisect import bisect from collections import OrderedDict from django.apps import apps from django.conf import settings from django.db.models.fields.related import ManyToManyRel from django.db.models.fields import AutoField, FieldDoesNotExist from django.db.models.fields.proxy import OrderWrt from django.utils import six from django.utils.encoding import force_text, smart_text, python_2_unicode_compatible from django.utils.functional import cached_property from django.utils.text import camel_case_to_spaces from django.utils.translation import activate, deactivate_all, get_language, string_concat DEFAULT_NAMES = ('verbose_name', 'verbose_name_plural', 'db_table', 'ordering', 'unique_together', 'permissions', 'get_latest_by', 'order_with_respect_to', 'app_label', 'db_tablespace', 'abstract', 'managed', 'proxy', 'swappable', 'auto_created', 'index_together', 'apps', 'default_permissions', 'select_on_save') def normalize_together(option_together): """ option_together can be either a tuple of tuples, or a single tuple of two strings. Normalize it to a tuple of tuples, so that calling code can uniformly expect that. """ try: if not option_together: return () if not isinstance(option_together, (tuple, list)): raise TypeError first_element = next(iter(option_together)) if not isinstance(first_element, (tuple, list)): option_together = (option_together,) # Normalize everything to tuples return tuple(tuple(ot) for ot in option_together) except TypeError: # If the value of option_together isn't valid, return it # verbatim; this will be picked up by the check framework later. return option_together @python_2_unicode_compatible class Options(object): def __init__(self, meta, app_label=None): self.local_fields = [] self.local_many_to_many = [] self.virtual_fields = [] self.model_name = None self.verbose_name = None self.verbose_name_plural = None self.db_table = '' self.ordering = [] self.unique_together = [] self.index_together = [] self.select_on_save = False self.default_permissions = ('add', 'change', 'delete') self.permissions = [] self.object_name = None self.app_label = app_label self.get_latest_by = None self.order_with_respect_to = None self.db_tablespace = settings.DEFAULT_TABLESPACE self.meta = meta self.pk = None self.has_auto_field = False self.auto_field = None self.abstract = False self.managed = True self.proxy = False # For any class that is a proxy (including automatically created # classes for deferred object loading), proxy_for_model tells us # which class this model is proxying. Note that proxy_for_model # can create a chain of proxy models. For non-proxy models, the # variable is always None. self.proxy_for_model = None # For any non-abstract class, the concrete class is the model # in the end of the proxy_for_model chain. In particular, for # concrete models, the concrete_model is always the class itself. self.concrete_model = None self.swappable = None self.parents = OrderedDict() self.auto_created = False # To handle various inheritance situations, we need to track where # managers came from (concrete or abstract base classes). self.abstract_managers = [] self.concrete_managers = [] # List of all lookups defined in ForeignKey 'limit_choices_to' options # from *other* models. Needed for some admin checks. Internal use only. self.related_fkey_lookups = [] # A custom app registry to use, if you're making a separate model set. self.apps = apps @property def app_config(self): # Don't go through get_app_config to avoid triggering imports. return self.apps.app_configs.get(self.app_label) @property def installed(self): return self.app_config is not None def contribute_to_class(self, cls, name): from django.db import connection from django.db.backends.utils import truncate_name cls._meta = self self.model = cls # First, construct the default values for these options. self.object_name = cls.__name__ self.model_name = self.object_name.lower() self.verbose_name = camel_case_to_spaces(self.object_name) # Store the original user-defined values for each option, # for use when serializing the model definition self.original_attrs = {} # Next, apply any overridden values from 'class Meta'. if self.meta: meta_attrs = self.meta.__dict__.copy() for name in self.meta.__dict__: # Ignore any private attributes that Django doesn't care about. # NOTE: We can't modify a dictionary's contents while looping # over it, so we loop over the *original* dictionary instead. if name.startswith('_'): del meta_attrs[name] for attr_name in DEFAULT_NAMES: if attr_name in meta_attrs: setattr(self, attr_name, meta_attrs.pop(attr_name)) self.original_attrs[attr_name] = getattr(self, attr_name) elif hasattr(self.meta, attr_name): setattr(self, attr_name, getattr(self.meta, attr_name)) self.original_attrs[attr_name] = getattr(self, attr_name) ut = meta_attrs.pop('unique_together', self.unique_together) self.unique_together = normalize_together(ut) it = meta_attrs.pop('index_together', self.index_together) self.index_together = normalize_together(it) # verbose_name_plural is a special case because it uses a 's' # by default. if self.verbose_name_plural is None: self.verbose_name_plural = string_concat(self.verbose_name, 's') # Any leftover attributes must be invalid. if meta_attrs != {}: raise TypeError("'class Meta' got invalid attribute(s): %s" % ','.join(meta_attrs.keys())) else: self.verbose_name_plural = string_concat(self.verbose_name, 's') del self.meta # If the db_table wasn't provided, use the app_label + model_name. if not self.db_table: self.db_table = "%s_%s" % (self.app_label, self.model_name) self.db_table = truncate_name(self.db_table, connection.ops.max_name_length()) def _prepare(self, model): if self.order_with_respect_to: self.order_with_respect_to = self.get_field(self.order_with_respect_to) self.ordering = ('_order',) model.add_to_class('_order', OrderWrt()) else: self.order_with_respect_to = None if self.pk is None: if self.parents: # Promote the first parent link in lieu of adding yet another # field. field = next(six.itervalues(self.parents)) # Look for a local field with the same name as the # first parent link. If a local field has already been # created, use it instead of promoting the parent already_created = [fld for fld in self.local_fields if fld.name == field.name] if already_created: field = already_created[0] field.primary_key = True self.setup_pk(field) else: auto = AutoField(verbose_name='ID', primary_key=True, auto_created=True) model.add_to_class('id', auto) def add_field(self, field): # Insert the given field in the order in which it was created, using # the "creation_counter" attribute of the field. # Move many-to-many related fields from self.fields into # self.many_to_many. if field.rel and isinstance(field.rel, ManyToManyRel): self.local_many_to_many.insert(bisect(self.local_many_to_many, field), field) if hasattr(self, '_m2m_cache'): del self._m2m_cache else: self.local_fields.insert(bisect(self.local_fields, field), field) self.setup_pk(field) if hasattr(self, '_field_cache'): del self._field_cache del self._field_name_cache # The fields, concrete_fields and local_concrete_fields are # implemented as cached properties for performance reasons. # The attrs will not exists if the cached property isn't # accessed yet, hence the try-excepts. try: del self.fields except AttributeError: pass try: del self.concrete_fields except AttributeError: pass try: del self.local_concrete_fields except AttributeError: pass if hasattr(self, '_name_map'): del self._name_map def add_virtual_field(self, field): self.virtual_fields.append(field) def setup_pk(self, field): if not self.pk and field.primary_key: self.pk = field field.serialize = False def pk_index(self): """ Returns the index of the primary key field in the self.concrete_fields list. """ return self.concrete_fields.index(self.pk) def setup_proxy(self, target): """ Does the internal setup so that the current model is a proxy for "target". """ self.pk = target._meta.pk self.proxy_for_model = target self.db_table = target._meta.db_table def __repr__(self): return '' % self.object_name def __str__(self): return "%s.%s" % (smart_text(self.app_label), smart_text(self.model_name)) def verbose_name_raw(self): """ There are a few places where the untranslated verbose name is needed (so that we get the same value regardless of currently active locale). """ lang = get_language() deactivate_all() raw = force_text(self.verbose_name) activate(lang) return raw verbose_name_raw = property(verbose_name_raw) def _swapped(self): """ Has this model been swapped out for another? If so, return the model name of the replacement; otherwise, return None. For historical reasons, model name lookups using get_model() are case insensitive, so we make sure we are case insensitive here. """ if self.swappable: model_label = '%s.%s' % (self.app_label, self.model_name) swapped_for = getattr(settings, self.swappable, None) if swapped_for: try: swapped_label, swapped_object = swapped_for.split('.') except ValueError: # setting not in the format app_label.model_name # raising ImproperlyConfigured here causes problems with # test cleanup code - instead it is raised in get_user_model # or as part of validation. return swapped_for if '%s.%s' % (swapped_label, swapped_object.lower()) not in (None, model_label): return swapped_for return None swapped = property(_swapped) @cached_property def fields(self): """ The getter for self.fields. This returns the list of field objects available to this model (including through parent models). Callers are not permitted to modify this list, since it's a reference to this instance (not a copy). """ try: self._field_name_cache except AttributeError: self._fill_fields_cache() return self._field_name_cache @cached_property def concrete_fields(self): return [f for f in self.fields if f.column is not None] @cached_property def local_concrete_fields(self): return [f for f in self.local_fields if f.column is not None] def get_fields_with_model(self): """ Returns a sequence of (field, model) pairs for all fields. The "model" element is None for fields on the current model. Mostly of use when constructing queries so that we know which model a field belongs to. """ try: self._field_cache except AttributeError: self._fill_fields_cache() return self._field_cache def get_concrete_fields_with_model(self): return [(field, model) for field, model in self.get_fields_with_model() if field.column is not None] def _fill_fields_cache(self): cache = [] for parent in self.parents: for field, model in parent._meta.get_fields_with_model(): if model: cache.append((field, model)) else: cache.append((field, parent)) cache.extend((f, None) for f in self.local_fields) self._field_cache = tuple(cache) self._field_name_cache = [x for x, _ in cache] def _many_to_many(self): try: self._m2m_cache except AttributeError: self._fill_m2m_cache() return list(self._m2m_cache) many_to_many = property(_many_to_many) def get_m2m_with_model(self): """ The many-to-many version of get_fields_with_model(). """ try: self._m2m_cache except AttributeError: self._fill_m2m_cache() return list(six.iteritems(self._m2m_cache)) def _fill_m2m_cache(self): cache = OrderedDict() for parent in self.parents: for field, model in parent._meta.get_m2m_with_model(): if model: cache[field] = model else: cache[field] = parent for field in self.local_many_to_many: cache[field] = None self._m2m_cache = cache def get_field(self, name, many_to_many=True): """ Returns the requested field by name. Raises FieldDoesNotExist on error. """ to_search = (self.fields + self.many_to_many) if many_to_many else self.fields for f in to_search: if f.name == name: return f raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, name)) def get_field_by_name(self, name): """ Returns the (field_object, model, direct, m2m), where field_object is the Field instance for the given name, model is the model containing this field (None for local fields), direct is True if the field exists on this model, and m2m is True for many-to-many relations. When 'direct' is False, 'field_object' is the corresponding RelatedObject for this field (since the field doesn't have an instance associated with it). Uses a cache internally, so after the first access, this is very fast. """ try: try: return self._name_map[name] except AttributeError: cache = self.init_name_map() return cache[name] except KeyError: raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, name)) def get_all_field_names(self): """ Returns a list of all field names that are possible for this model (including reverse relation names). This is used for pretty printing debugging output (a list of choices), so any internal-only field names are not included. """ try: cache = self._name_map except AttributeError: cache = self.init_name_map() names = sorted(cache.keys()) # Internal-only names end with "+" (symmetrical m2m related names being # the main example). Trim them. return [val for val in names if not val.endswith('+')] def init_name_map(self): """ Initialises the field name -> field object mapping. """ cache = {} # We intentionally handle related m2m objects first so that symmetrical # m2m accessor names can be overridden, if necessary. for f, model in self.get_all_related_m2m_objects_with_model(): cache[f.field.related_query_name()] = (f, model, False, True) for f, model in self.get_all_related_objects_with_model(): cache[f.field.related_query_name()] = (f, model, False, False) for f, model in self.get_m2m_with_model(): cache[f.name] = cache[f.attname] = (f, model, True, True) for f, model in self.get_fields_with_model(): cache[f.name] = cache[f.attname] = (f, model, True, False) for f in self.virtual_fields: cache[f.name] = (f, None if f.model == self.model else f.model, True, False) if apps.ready: self._name_map = cache return cache def get_all_related_objects(self, local_only=False, include_hidden=False, include_proxy_eq=False): return [k for k, v in self.get_all_related_objects_with_model( local_only=local_only, include_hidden=include_hidden, include_proxy_eq=include_proxy_eq)] def get_all_related_objects_with_model(self, local_only=False, include_hidden=False, include_proxy_eq=False): """ Returns a list of (related-object, model) pairs. Similar to get_fields_with_model(). """ try: self._related_objects_cache except AttributeError: self._fill_related_objects_cache() predicates = [] if local_only: predicates.append(lambda k, v: not v) if not include_hidden: predicates.append(lambda k, v: not k.field.rel.is_hidden()) cache = (self._related_objects_proxy_cache if include_proxy_eq else self._related_objects_cache) return [t for t in cache.items() if all(p(*t) for p in predicates)] def _fill_related_objects_cache(self): cache = OrderedDict() parent_list = self.get_parent_list() for parent in self.parents: for obj, model in parent._meta.get_all_related_objects_with_model(include_hidden=True): if (obj.field.creation_counter < 0 or obj.field.rel.parent_link) and obj.model not in parent_list: continue if not model: cache[obj] = parent else: cache[obj] = model # Collect also objects which are in relation to some proxy child/parent of self. proxy_cache = cache.copy() for klass in self.apps.get_models(include_auto_created=True): if not klass._meta.swapped: for f in klass._meta.local_fields + klass._meta.virtual_fields: if (hasattr(f, 'rel') and f.rel and not isinstance(f.rel.to, six.string_types) and f.generate_reverse_relation): if self == f.rel.to._meta: cache[f.related] = None proxy_cache[f.related] = None elif self.concrete_model == f.rel.to._meta.concrete_model: proxy_cache[f.related] = None self._related_objects_cache = cache self._related_objects_proxy_cache = proxy_cache def get_all_related_many_to_many_objects(self, local_only=False): try: cache = self._related_many_to_many_cache except AttributeError: cache = self._fill_related_many_to_many_cache() if local_only: return [k for k, v in cache.items() if not v] return list(cache) def get_all_related_m2m_objects_with_model(self): """ Returns a list of (related-m2m-object, model) pairs. Similar to get_fields_with_model(). """ try: cache = self._related_many_to_many_cache except AttributeError: cache = self._fill_related_many_to_many_cache() return list(six.iteritems(cache)) def _fill_related_many_to_many_cache(self): cache = OrderedDict() parent_list = self.get_parent_list() for parent in self.parents: for obj, model in parent._meta.get_all_related_m2m_objects_with_model(): if obj.field.creation_counter < 0 and obj.model not in parent_list: continue if not model: cache[obj] = parent else: cache[obj] = model for klass in self.apps.get_models(): if not klass._meta.swapped: for f in klass._meta.local_many_to_many: if (f.rel and not isinstance(f.rel.to, six.string_types) and self == f.rel.to._meta): cache[f.related] = None if apps.ready: self._related_many_to_many_cache = cache return cache def get_base_chain(self, model): """ Returns a list of parent classes leading to 'model' (order from closet to most distant ancestor). This has to handle the case were 'model' is a granparent or even more distant relation. """ if not self.parents: return None if model in self.parents: return [model] for parent in self.parents: res = parent._meta.get_base_chain(model) if res: res.insert(0, parent) return res return None def get_parent_list(self): """ Returns a list of all the ancestor of this model as a list. Useful for determining if something is an ancestor, regardless of lineage. """ result = set() for parent in self.parents: result.add(parent) result.update(parent._meta.get_parent_list()) return result def get_ancestor_link(self, ancestor): """ Returns the field on the current model which points to the given "ancestor". This is possible an indirect link (a pointer to a parent model, which points, eventually, to the ancestor). Used when constructing table joins for model inheritance. Returns None if the model isn't an ancestor of this one. """ if ancestor in self.parents: return self.parents[ancestor] for parent in self.parents: # Tries to get a link field from the immediate parent parent_link = parent._meta.get_ancestor_link(ancestor) if parent_link: # In case of a proxied model, the first link # of the chain to the ancestor is that parent # links return self.parents[parent] or parent_link