--- /dev/null
+from django.core.validators import slug_re
+from django.template.defaultfilters import slugify
+from django.utils.encoding import smart_str
+
+
+class RegistryIterator(object):
+ """
+ Wraps the iterator returned by calling ``getattr(registry, iterattr)`` to provide late instantiation of the wrapped iterator and to allow copying of the iterator for even later instantiation.
+
+ :param registry: The object which provides the iterator at ``iterattr``.
+ :param iterattr: The name of the method on ``registry`` that provides the iterator.
+ :param transform: A function which will be called on each result from the wrapped iterator before it is returned.
+
+ """
+ def __init__(self, registry, iterattr='__iter__', transform=lambda x:x):
+ if not hasattr(registry, iterattr):
+ raise AttributeError("Registry has no attribute %s" % iterattr)
+ self.registry = registry
+ self.iterattr = iterattr
+ self.transform = transform
+
+ def __iter__(self):
+ return self
+
+ def next(self):
+ if not hasattr(self, '_iter'):
+ self._iter = getattr(self.registry, self.iterattr)()
+
+ return self.transform(self._iter.next())
+
+ def copy(self):
+ """Returns a fresh copy of this iterator."""
+ return self.__class__(self.registry, self.iterattr, self.transform)
+
+
+class RegistrationError(Exception):
+ """Raised if there is a problem registering a object with a :class:`Registry`"""
+ pass
+
+
+class Registry(object):
+ """Holds a registry of arbitrary objects by slug."""
+
+ def __init__(self):
+ self._registry = {}
+
+ def register(self, obj, slug=None, verbose_name=None):
+ """
+ Register an object with the registry.
+
+ :param obj: The object to register.
+ :param slug: The slug which will be used to register the object. If ``slug`` is ``None``, it will be generated from ``verbose_name`` or looked for at ``obj.slug``.
+ :param verbose_name: The verbose name for the object. If ``verbose_name`` is ``None``, it will be looked for at ``obj.verbose_name``.
+ :raises: :class:`RegistrationError` if a different object is already registered with ``slug``, or if ``slug`` is not a valid slug.
+
+ """
+ verbose_name = verbose_name if verbose_name is not None else obj.verbose_name
+
+ if slug is None:
+ slug = getattr(obj, 'slug', slugify(verbose_name))
+ slug = smart_str(slug)
+
+ if not slug_re.search(slug):
+ raise RegistrationError(u"%s is not a valid slug." % slug)
+
+
+ if slug in self._registry:
+ reg = self._registry[slug]
+ if reg['obj'] != obj:
+ raise RegistrationError(u"A different object is already registered as `%s`" % slug)
+ else:
+ self._registry[slug] = {
+ 'obj': obj,
+ 'verbose_name': verbose_name
+ }
+
+ def unregister(self, obj, slug=None):
+ """
+ Unregister an object from the registry.
+
+ :param obj: The object to unregister.
+ :param slug: If provided, the object will only be removed if it was registered with ``slug``. If not provided, the object will be unregistered no matter what slug it was registered with.
+ :raises: :class:`RegistrationError` if ``slug`` is provided and an object other than ``obj`` is registered as ``slug``.
+
+ """
+ if slug is not None:
+ if slug in self._registry:
+ if self._registry[slug]['obj'] == obj:
+ del self._registry[slug]
+ else:
+ raise RegistrationError(u"`%s` is not registered as `%s`" % (obj, slug))
+ else:
+ for slug, reg in self.items():
+ if obj == reg:
+ del self._registry[slug]
+
+ def items(self):
+ """Returns a list of (slug, obj) items in the registry."""
+ return [(slug, self[slug]) for slug in self._registry]
+
+ def values(self):
+ """Returns a list of objects in the registry."""
+ return [self[slug] for slug in self._registry]
+
+ def iteritems(self):
+ """Returns a :class:`RegistryIterator` over the (slug, obj) pairs in the registry."""
+ return RegistryIterator(self._registry, 'iteritems', lambda x: (x[0], x[1]['obj']))
+
+ def itervalues(self):
+ """Returns a :class:`RegistryIterator` over the objects in the registry."""
+ return RegistryIterator(self._registry, 'itervalues', lambda x: x['obj'])
+
+ def iterchoices(self):
+ """Returns a :class:`RegistryIterator` over (slug, verbose_name) pairs for the registry."""
+ return RegistryIterator(self._registry, 'iteritems', lambda x: (x[0], x[1]['verbose_name']))
+ choices = property(iterchoices)
+
+ def get(self, key, default=None):
+ """Returns the object registered with ``key`` or ``default`` if no object was registered."""
+ try:
+ return self[key]
+ except KeyError:
+ return default
+
+ def get_slug(self, obj, default=None):
+ """Returns the slug used to register ``obj`` or ``default`` if ``obj`` was not registered."""
+ for slug, reg in self.iteritems():
+ if obj == reg:
+ return slug
+ return default
+
+ def __getitem__(self, key):
+ """Returns the obj registered with ``key``."""
+ return self._registry[key]['obj']
+
+ def __iter__(self):
+ """Returns an iterator over the keys in the registry."""
+ return self._registry.__iter__()
+
+ def __contains__(self, item):
+ return self._registry.__contains__(item)
\ No newline at end of file
git.ithinksw.org / philo.git / blobdiff