Implementation of basic conversion between Django forms and ExtJS forms.

[philo.git] / utils.py

diff --git a/utils.py b/utils.py
index e3d1124..6fc2cff 100644 (file)
--- a/utils.py
+++ b/utils.py
@@ -1,6 +1,105 @@
+from django.db import models
+from django.contrib.contenttypes.models import ContentType
+from django.core.paginator import Paginator, EmptyPage
+
+
+class ContentTypeLimiter(object):
+       def q_object(self):
+               return models.Q(pk__in=[])
+       
+       def add_to_query(self, query, *args, **kwargs):
+               query.add_q(self.q_object(), *args, **kwargs)
+
+
+class ContentTypeRegistryLimiter(ContentTypeLimiter):
+       def __init__(self):
+               self.classes = []
+       
+       def register_class(self, cls):
+               self.classes.append(cls)
+       
+       def unregister_class(self, cls):
+               self.classes.remove(cls)
+       
+       def q_object(self):
+               contenttype_pks = []
+               for cls in self.classes:
+                       try:
+                               if issubclass(cls, models.Model):
+                                       if not cls._meta.abstract:
+                                               contenttype = ContentType.objects.get_for_model(cls)
+                                               contenttype_pks.append(contenttype.pk)
+                       except:
+                               pass
+               return models.Q(pk__in=contenttype_pks)
+
+
+class ContentTypeSubclassLimiter(ContentTypeLimiter):
+       def __init__(self, cls, inclusive=False):
+               self.cls = cls
+               self.inclusive = inclusive
+       
+       def q_object(self):
+               contenttype_pks = []
+               def handle_subclasses(cls):
+                       for subclass in cls.__subclasses__():
+                               try:
+                                       if issubclass(subclass, models.Model):
+                                               if not subclass._meta.abstract:
+                                                       if not self.inclusive and subclass is self.cls:
+                                                               continue
+                                                       contenttype = ContentType.objects.get_for_model(subclass)
+                                                       contenttype_pks.append(contenttype.pk)
+                                       handle_subclasses(subclass)
+                               except:
+                                       pass
+               handle_subclasses(self.cls)
+               return models.Q(pk__in=contenttype_pks)
+
+
 def fattr(*args, **kwargs):
        def wrapper(function):
                for key in kwargs:
                        setattr(function, key, kwargs[key])
                return function
        return wrapper
+
+
+def paginate(objects, per_page=None, page_number=1):
+       """
+       Given a list of objects, return a (paginator, page, objects) tuple.
+       """
+       try:
+               per_page = int(per_page)
+       except (TypeError, ValueError):
+               # Then either it wasn't set or it was set to an invalid value
+               paginator = page = None
+       else:
+               # There also shouldn't be pagination if the list is too short. Try count()
+               # first - good chance it's a queryset, where count is more efficient.
+               try:
+                       if objects.count() <= per_page:
+                               paginator = page = None
+               except AttributeError:
+                       if len(objects) <= per_page:
+                               paginator = page = None
+       
+       try:
+               return paginator, page, objects
+       except NameError:
+               pass
+       
+       paginator = Paginator(objects, per_page)
+       try:
+               page_number = int(page_number)
+       except:
+               page_number = 1
+       
+       try:
+               page = paginator.page(page_number)
+       except EmptyPage:
+               page = None
+       else:
+               objects = page.object_list
+       
+       return paginator, page, objects