485 lines
19 KiB
Python
485 lines
19 KiB
Python
import re
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from bisect import bisect
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from django.conf import settings
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from django.db.models.related import RelatedObject
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from django.db.models.fields.related import ManyToManyRel
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from django.db.models.fields import AutoField, FieldDoesNotExist
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from django.db.models.fields.proxy import OrderWrt
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from django.db.models.loading import get_models, app_cache_ready
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from django.utils.translation import activate, deactivate_all, get_language, string_concat
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from django.utils.encoding import force_unicode, smart_str
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from django.utils.datastructures import SortedDict
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# Calculate the verbose_name by converting from InitialCaps to "lowercase with spaces".
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get_verbose_name = lambda class_name: re.sub('(((?<=[a-z])[A-Z])|([A-Z](?![A-Z]|$)))', ' \\1', class_name).lower().strip()
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DEFAULT_NAMES = ('verbose_name', 'db_table', 'ordering',
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'unique_together', 'permissions', 'get_latest_by',
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'order_with_respect_to', 'app_label', 'db_tablespace',
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'abstract', 'managed', 'proxy', 'auto_created')
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class Options(object):
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def __init__(self, meta, app_label=None):
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self.local_fields, self.local_many_to_many = [], []
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self.virtual_fields = []
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self.module_name, self.verbose_name = None, None
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self.verbose_name_plural = None
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self.db_table = ''
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self.ordering = []
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self.unique_together = []
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self.permissions = []
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self.object_name, self.app_label = None, app_label
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self.get_latest_by = None
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self.order_with_respect_to = None
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self.db_tablespace = settings.DEFAULT_TABLESPACE
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self.admin = None
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self.meta = meta
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self.pk = None
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self.has_auto_field, self.auto_field = False, None
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self.abstract = False
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self.managed = True
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self.proxy = False
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self.proxy_for_model = None
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self.parents = SortedDict()
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self.duplicate_targets = {}
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self.auto_created = False
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# To handle various inheritance situations, we need to track where
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# managers came from (concrete or abstract base classes).
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self.abstract_managers = []
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self.concrete_managers = []
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def contribute_to_class(self, cls, name):
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from django.db import connection
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from django.db.backends.util import truncate_name
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cls._meta = self
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self.installed = re.sub('\.models$', '', cls.__module__) in settings.INSTALLED_APPS
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# First, construct the default values for these options.
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self.object_name = cls.__name__
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self.module_name = self.object_name.lower()
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self.verbose_name = get_verbose_name(self.object_name)
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# Next, apply any overridden values from 'class Meta'.
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if self.meta:
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meta_attrs = self.meta.__dict__.copy()
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for name in self.meta.__dict__:
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# Ignore any private attributes that Django doesn't care about.
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# NOTE: We can't modify a dictionary's contents while looping
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# over it, so we loop over the *original* dictionary instead.
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if name.startswith('_'):
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del meta_attrs[name]
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for attr_name in DEFAULT_NAMES:
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if attr_name in meta_attrs:
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setattr(self, attr_name, meta_attrs.pop(attr_name))
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elif hasattr(self.meta, attr_name):
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setattr(self, attr_name, getattr(self.meta, attr_name))
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# unique_together can be either a tuple of tuples, or a single
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# tuple of two strings. Normalize it to a tuple of tuples, so that
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# calling code can uniformly expect that.
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ut = meta_attrs.pop('unique_together', self.unique_together)
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if ut and not isinstance(ut[0], (tuple, list)):
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ut = (ut,)
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self.unique_together = ut
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# verbose_name_plural is a special case because it uses a 's'
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# by default.
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self.verbose_name_plural = meta_attrs.pop('verbose_name_plural', string_concat(self.verbose_name, 's'))
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# Any leftover attributes must be invalid.
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if meta_attrs != {}:
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raise TypeError("'class Meta' got invalid attribute(s): %s" % ','.join(meta_attrs.keys()))
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else:
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self.verbose_name_plural = string_concat(self.verbose_name, 's')
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del self.meta
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# If the db_table wasn't provided, use the app_label + module_name.
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if not self.db_table:
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self.db_table = "%s_%s" % (self.app_label, self.module_name)
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self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
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def _prepare(self, model):
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if self.order_with_respect_to:
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self.order_with_respect_to = self.get_field(self.order_with_respect_to)
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self.ordering = ('_order',)
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model.add_to_class('_order', OrderWrt())
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else:
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self.order_with_respect_to = None
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if self.pk is None:
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if self.parents:
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# Promote the first parent link in lieu of adding yet another
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# field.
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field = self.parents.value_for_index(0)
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field.primary_key = True
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self.setup_pk(field)
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else:
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auto = AutoField(verbose_name='ID', primary_key=True,
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auto_created=True)
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model.add_to_class('id', auto)
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# Determine any sets of fields that are pointing to the same targets
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# (e.g. two ForeignKeys to the same remote model). The query
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# construction code needs to know this. At the end of this,
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# self.duplicate_targets will map each duplicate field column to the
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# columns it duplicates.
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collections = {}
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for column, target in self.duplicate_targets.iteritems():
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try:
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collections[target].add(column)
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except KeyError:
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collections[target] = set([column])
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self.duplicate_targets = {}
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for elt in collections.itervalues():
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if len(elt) == 1:
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continue
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for column in elt:
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self.duplicate_targets[column] = elt.difference(set([column]))
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def add_field(self, field):
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# Insert the given field in the order in which it was created, using
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# the "creation_counter" attribute of the field.
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# Move many-to-many related fields from self.fields into
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# self.many_to_many.
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if field.rel and isinstance(field.rel, ManyToManyRel):
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self.local_many_to_many.insert(bisect(self.local_many_to_many, field), field)
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if hasattr(self, '_m2m_cache'):
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del self._m2m_cache
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else:
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self.local_fields.insert(bisect(self.local_fields, field), field)
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self.setup_pk(field)
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if hasattr(self, '_field_cache'):
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del self._field_cache
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del self._field_name_cache
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if hasattr(self, '_name_map'):
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del self._name_map
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def add_virtual_field(self, field):
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self.virtual_fields.append(field)
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def setup_pk(self, field):
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if not self.pk and field.primary_key:
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self.pk = field
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field.serialize = False
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def setup_proxy(self, target):
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"""
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Does the internal setup so that the current model is a proxy for
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"target".
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"""
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self.pk = target._meta.pk
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self.proxy_for_model = target
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self.db_table = target._meta.db_table
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def __repr__(self):
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return '<Options for %s>' % self.object_name
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def __str__(self):
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return "%s.%s" % (smart_str(self.app_label), smart_str(self.module_name))
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def verbose_name_raw(self):
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"""
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There are a few places where the untranslated verbose name is needed
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(so that we get the same value regardless of currently active
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locale).
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"""
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lang = get_language()
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deactivate_all()
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raw = force_unicode(self.verbose_name)
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activate(lang)
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return raw
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verbose_name_raw = property(verbose_name_raw)
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def _fields(self):
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"""
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The getter for self.fields. This returns the list of field objects
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available to this model (including through parent models).
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Callers are not permitted to modify this list, since it's a reference
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to this instance (not a copy).
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"""
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try:
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self._field_name_cache
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except AttributeError:
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self._fill_fields_cache()
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return self._field_name_cache
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fields = property(_fields)
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def get_fields_with_model(self):
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"""
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Returns a sequence of (field, model) pairs for all fields. The "model"
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element is None for fields on the current model. Mostly of use when
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constructing queries so that we know which model a field belongs to.
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"""
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try:
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self._field_cache
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except AttributeError:
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self._fill_fields_cache()
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return self._field_cache
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def _fill_fields_cache(self):
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cache = []
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for parent in self.parents:
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for field, model in parent._meta.get_fields_with_model():
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if model:
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cache.append((field, model))
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else:
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cache.append((field, parent))
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cache.extend([(f, None) for f in self.local_fields])
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self._field_cache = tuple(cache)
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self._field_name_cache = [x for x, _ in cache]
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def _many_to_many(self):
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try:
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self._m2m_cache
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except AttributeError:
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self._fill_m2m_cache()
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return self._m2m_cache.keys()
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many_to_many = property(_many_to_many)
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def get_m2m_with_model(self):
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"""
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The many-to-many version of get_fields_with_model().
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"""
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try:
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self._m2m_cache
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except AttributeError:
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self._fill_m2m_cache()
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return self._m2m_cache.items()
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def _fill_m2m_cache(self):
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cache = SortedDict()
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for parent in self.parents:
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for field, model in parent._meta.get_m2m_with_model():
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if model:
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cache[field] = model
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else:
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cache[field] = parent
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for field in self.local_many_to_many:
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cache[field] = None
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self._m2m_cache = cache
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def get_field(self, name, many_to_many=True):
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"""
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Returns the requested field by name. Raises FieldDoesNotExist on error.
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"""
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to_search = many_to_many and (self.fields + self.many_to_many) or self.fields
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for f in to_search:
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if f.name == name:
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return f
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raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, name))
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def get_field_by_name(self, name):
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"""
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Returns the (field_object, model, direct, m2m), where field_object is
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the Field instance for the given name, model is the model containing
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this field (None for local fields), direct is True if the field exists
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on this model, and m2m is True for many-to-many relations. When
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'direct' is False, 'field_object' is the corresponding RelatedObject
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for this field (since the field doesn't have an instance associated
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with it).
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Uses a cache internally, so after the first access, this is very fast.
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"""
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try:
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try:
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return self._name_map[name]
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except AttributeError:
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cache = self.init_name_map()
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return cache[name]
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except KeyError:
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raise FieldDoesNotExist('%s has no field named %r'
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% (self.object_name, name))
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def get_all_field_names(self):
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"""
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Returns a list of all field names that are possible for this model
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(including reverse relation names). This is used for pretty printing
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debugging output (a list of choices), so any internal-only field names
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are not included.
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"""
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try:
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cache = self._name_map
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except AttributeError:
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cache = self.init_name_map()
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names = cache.keys()
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names.sort()
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# Internal-only names end with "+" (symmetrical m2m related names being
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# the main example). Trim them.
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return [val for val in names if not val.endswith('+')]
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def init_name_map(self):
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"""
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Initialises the field name -> field object mapping.
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"""
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cache = {}
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# We intentionally handle related m2m objects first so that symmetrical
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# m2m accessor names can be overridden, if necessary.
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for f, model in self.get_all_related_m2m_objects_with_model():
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cache[f.field.related_query_name()] = (f, model, False, True)
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for f, model in self.get_all_related_objects_with_model():
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cache[f.field.related_query_name()] = (f, model, False, False)
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for f, model in self.get_m2m_with_model():
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cache[f.name] = (f, model, True, True)
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for f, model in self.get_fields_with_model():
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cache[f.name] = (f, model, True, False)
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if app_cache_ready():
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self._name_map = cache
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return cache
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def get_add_permission(self):
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return 'add_%s' % self.object_name.lower()
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def get_change_permission(self):
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return 'change_%s' % self.object_name.lower()
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def get_delete_permission(self):
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return 'delete_%s' % self.object_name.lower()
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def get_all_related_objects(self, local_only=False):
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try:
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self._related_objects_cache
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except AttributeError:
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self._fill_related_objects_cache()
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if local_only:
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return [k for k, v in self._related_objects_cache.items() if not v]
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return self._related_objects_cache.keys()
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def get_all_related_objects_with_model(self):
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"""
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Returns a list of (related-object, model) pairs. Similar to
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get_fields_with_model().
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"""
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try:
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self._related_objects_cache
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except AttributeError:
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self._fill_related_objects_cache()
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return self._related_objects_cache.items()
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def _fill_related_objects_cache(self):
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cache = SortedDict()
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parent_list = self.get_parent_list()
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for parent in self.parents:
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for obj, model in parent._meta.get_all_related_objects_with_model():
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if (obj.field.creation_counter < 0 or obj.field.rel.parent_link) and obj.model not in parent_list:
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continue
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if not model:
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cache[obj] = parent
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else:
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cache[obj] = model
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for klass in get_models():
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for f in klass._meta.local_fields:
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if f.rel and not isinstance(f.rel.to, str) and self == f.rel.to._meta:
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cache[RelatedObject(f.rel.to, klass, f)] = None
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self._related_objects_cache = cache
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def get_all_related_many_to_many_objects(self, local_only=False):
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try:
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cache = self._related_many_to_many_cache
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except AttributeError:
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cache = self._fill_related_many_to_many_cache()
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if local_only:
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return [k for k, v in cache.items() if not v]
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return cache.keys()
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def get_all_related_m2m_objects_with_model(self):
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"""
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Returns a list of (related-m2m-object, model) pairs. Similar to
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get_fields_with_model().
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"""
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try:
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cache = self._related_many_to_many_cache
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except AttributeError:
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cache = self._fill_related_many_to_many_cache()
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return cache.items()
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def _fill_related_many_to_many_cache(self):
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cache = SortedDict()
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parent_list = self.get_parent_list()
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for parent in self.parents:
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for obj, model in parent._meta.get_all_related_m2m_objects_with_model():
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if obj.field.creation_counter < 0 and obj.model not in parent_list:
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continue
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if not model:
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cache[obj] = parent
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else:
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cache[obj] = model
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for klass in get_models():
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for f in klass._meta.local_many_to_many:
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if f.rel and not isinstance(f.rel.to, str) and self == f.rel.to._meta:
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cache[RelatedObject(f.rel.to, klass, f)] = None
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if app_cache_ready():
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self._related_many_to_many_cache = cache
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return cache
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def get_base_chain(self, model):
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"""
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Returns a list of parent classes leading to 'model' (order from closet
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to most distant ancestor). This has to handle the case were 'model' is
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a granparent or even more distant relation.
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"""
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if not self.parents:
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return
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if model in self.parents:
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return [model]
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for parent in self.parents:
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res = parent._meta.get_base_chain(model)
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if res:
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res.insert(0, parent)
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return res
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raise TypeError('%r is not an ancestor of this model'
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% model._meta.module_name)
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def get_parent_list(self):
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"""
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Returns a list of all the ancestor of this model as a list. Useful for
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determining if something is an ancestor, regardless of lineage.
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"""
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result = set()
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for parent in self.parents:
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result.add(parent)
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result.update(parent._meta.get_parent_list())
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return result
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def get_ancestor_link(self, ancestor):
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"""
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Returns the field on the current model which points to the given
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"ancestor". This is possible an indirect link (a pointer to a parent
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model, which points, eventually, to the ancestor). Used when
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constructing table joins for model inheritance.
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Returns None if the model isn't an ancestor of this one.
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"""
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if ancestor in self.parents:
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return self.parents[ancestor]
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for parent in self.parents:
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# Tries to get a link field from the immediate parent
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parent_link = parent._meta.get_ancestor_link(ancestor)
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if parent_link:
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# In case of a proxied model, the first link
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# of the chain to the ancestor is that parent
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# links
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return self.parents[parent] or parent_link
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def get_ordered_objects(self):
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"Returns a list of Options objects that are ordered with respect to this object."
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if not hasattr(self, '_ordered_objects'):
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objects = []
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# TODO
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#for klass in get_models(get_app(self.app_label)):
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# opts = klass._meta
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# if opts.order_with_respect_to and opts.order_with_respect_to.rel \
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# and self == opts.order_with_respect_to.rel.to._meta:
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# objects.append(opts)
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self._ordered_objects = objects
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return self._ordered_objects
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def pk_index(self):
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"""
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Returns the index of the primary key field in the self.fields list.
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"""
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return self.fields.index(self.pk)
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