web/lib/django/db/models/options.py
changeset 0 0d40e90630ef
child 29 cc9b7e14412b
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django/db/models/options.py	Wed Jan 20 00:34:04 2010 +0100
@@ -0,0 +1,490 @@
+import re
+from bisect import bisect
+try:
+    set
+except NameError:
+    from sets import Set as set     # Python 2.3 fallback
+
+from django.conf import settings
+from django.db.models.related import RelatedObject
+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.db.models.loading import get_models, app_cache_ready
+from django.utils.translation import activate, deactivate_all, get_language, string_concat
+from django.utils.encoding import force_unicode, smart_str
+from django.utils.datastructures import SortedDict
+
+# Calculate the verbose_name by converting from InitialCaps to "lowercase with spaces".
+get_verbose_name = lambda class_name: re.sub('(((?<=[a-z])[A-Z])|([A-Z](?![A-Z]|$)))', ' \\1', class_name).lower().strip()
+
+DEFAULT_NAMES = ('verbose_name', 'db_table', 'ordering',
+                 'unique_together', 'permissions', 'get_latest_by',
+                 'order_with_respect_to', 'app_label', 'db_tablespace',
+                 'abstract', 'managed', 'proxy')
+
+class Options(object):
+    def __init__(self, meta, app_label=None):
+        self.local_fields, self.local_many_to_many = [], []
+        self.virtual_fields = []
+        self.module_name, self.verbose_name = None, None
+        self.verbose_name_plural = None
+        self.db_table = ''
+        self.ordering = []
+        self.unique_together =  []
+        self.permissions =  []
+        self.object_name, self.app_label = None, app_label
+        self.get_latest_by = None
+        self.order_with_respect_to = None
+        self.db_tablespace = settings.DEFAULT_TABLESPACE
+        self.admin = None
+        self.meta = meta
+        self.pk = None
+        self.has_auto_field, self.auto_field = False, None
+        self.abstract = False
+        self.managed = True
+        self.proxy = False
+        self.proxy_for_model = None
+        self.parents = SortedDict()
+        self.duplicate_targets = {}
+
+        # To handle various inheritance situations, we need to track where
+        # managers came from (concrete or abstract base classes).
+        self.abstract_managers = []
+        self.concrete_managers = []
+
+    def contribute_to_class(self, cls, name):
+        from django.db import connection
+        from django.db.backends.util import truncate_name
+
+        cls._meta = self
+        self.installed = re.sub('\.models$', '', cls.__module__) in settings.INSTALLED_APPS
+        # First, construct the default values for these options.
+        self.object_name = cls.__name__
+        self.module_name = self.object_name.lower()
+        self.verbose_name = get_verbose_name(self.object_name)
+
+        # 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))
+                elif hasattr(self.meta, attr_name):
+                    setattr(self, attr_name, getattr(self.meta, attr_name))
+
+            # unique_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.
+            ut = meta_attrs.pop('unique_together', getattr(self, 'unique_together'))
+            if ut and not isinstance(ut[0], (tuple, list)):
+                ut = (ut,)
+            setattr(self, 'unique_together', ut)
+
+            # verbose_name_plural is a special case because it uses a 's'
+            # by default.
+            setattr(self, 'verbose_name_plural', meta_attrs.pop('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 + module_name.
+        if not self.db_table:
+            self.db_table = "%s_%s" % (self.app_label, self.module_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',)
+        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 = self.parents.value_for_index(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)
+
+        # Determine any sets of fields that are pointing to the same targets
+        # (e.g. two ForeignKeys to the same remote model). The query
+        # construction code needs to know this. At the end of this,
+        # self.duplicate_targets will map each duplicate field column to the
+        # columns it duplicates.
+        collections = {}
+        for column, target in self.duplicate_targets.iteritems():
+            try:
+                collections[target].add(column)
+            except KeyError:
+                collections[target] = set([column])
+        self.duplicate_targets = {}
+        for elt in collections.itervalues():
+            if len(elt) == 1:
+                continue
+            for column in elt:
+                self.duplicate_targets[column] = elt.difference(set([column]))
+
+    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
+
+        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 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 '<Options for %s>' % self.object_name
+
+    def __str__(self):
+        return "%s.%s" % (smart_str(self.app_label), smart_str(self.module_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_unicode(self.verbose_name)
+        activate(lang)
+        return raw
+    verbose_name_raw = property(verbose_name_raw)
+
+    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
+    fields = property(_fields)
+
+    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 _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 self._m2m_cache.keys()
+    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 self._m2m_cache.items()
+
+    def _fill_m2m_cache(self):
+        cache = SortedDict()
+        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 = many_to_many and (self.fields + self.many_to_many) or 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 = cache.keys()
+        names.sort()
+        # 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] = (f, model, True, True)
+        for f, model in self.get_fields_with_model():
+            cache[f.name] = (f, model, True, False)
+        if self.order_with_respect_to:
+            cache['_order'] = OrderWrt(), None, True, False
+        if app_cache_ready():
+            self._name_map = cache
+        return cache
+
+    def get_add_permission(self):
+        return 'add_%s' % self.object_name.lower()
+
+    def get_change_permission(self):
+        return 'change_%s' % self.object_name.lower()
+
+    def get_delete_permission(self):
+        return 'delete_%s' % self.object_name.lower()
+
+    def get_all_related_objects(self, local_only=False):
+        try:
+            self._related_objects_cache
+        except AttributeError:
+            self._fill_related_objects_cache()
+        if local_only:
+            return [k for k, v in self._related_objects_cache.items() if not v]
+        return self._related_objects_cache.keys()
+
+    def get_all_related_objects_with_model(self):
+        """
+        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()
+        return self._related_objects_cache.items()
+
+    def _fill_related_objects_cache(self):
+        cache = SortedDict()
+        parent_list = self.get_parent_list()
+        for parent in self.parents:
+            for obj, model in parent._meta.get_all_related_objects_with_model():
+                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
+        for klass in get_models():
+            for f in klass._meta.local_fields:
+                if f.rel and not isinstance(f.rel.to, str) and self == f.rel.to._meta:
+                    cache[RelatedObject(f.rel.to, klass, f)] = None
+        self._related_objects_cache = 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 cache.keys()
+
+    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 cache.items()
+
+    def _fill_related_many_to_many_cache(self):
+        cache = SortedDict()
+        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 get_models():
+            for f in klass._meta.local_many_to_many:
+                if f.rel and not isinstance(f.rel.to, str) and self == f.rel.to._meta:
+                    cache[RelatedObject(f.rel.to, klass, f)] = None
+        if app_cache_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
+        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
+        raise TypeError('%r is not an ancestor of this model'
+                % model._meta.module_name)
+
+    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
+
+    def get_ordered_objects(self):
+        "Returns a list of Options objects that are ordered with respect to this object."
+        if not hasattr(self, '_ordered_objects'):
+            objects = []
+            # TODO
+            #for klass in get_models(get_app(self.app_label)):
+            #    opts = klass._meta
+            #    if opts.order_with_respect_to and opts.order_with_respect_to.rel \
+            #        and self == opts.order_with_respect_to.rel.to._meta:
+            #        objects.append(opts)
+            self._ordered_objects = objects
+        return self._ordered_objects
+
+    def pk_index(self):
+        """
+        Returns the index of the primary key field in the self.fields list.
+        """
+        return self.fields.index(self.pk)
+