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450 lines
18 KiB
450 lines
18 KiB
import re |
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from bisect import bisect |
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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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|
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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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|
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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') |
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|
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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.one_to_one_field = None |
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self.abstract = False |
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self.parents = SortedDict() |
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self.duplicate_targets = {} |
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# Managers that have been inherited from abstract base classes. These |
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# are passed onto any children. |
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self.abstract_managers = [] |
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|
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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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|
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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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|
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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', getattr(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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setattr(self, 'unique_together', ut) |
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|
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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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setattr(self, 'verbose_name_plural', meta_attrs.pop('verbose_name_plural', string_concat(self.verbose_name, 's'))) |
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|
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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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|
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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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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 __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 self.order_with_respect_to: |
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cache['_order'] = OrderWrt(), None, 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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|
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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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|
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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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|
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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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