Genericized nodelist_crawl to just pass each node to a callback function. Overloaded...

[philo.git] / utils.py

diff --git a/utils.py b/utils.py
index 340e9e4..a968ac8 100644 (file)
--- a/utils.py
+++ b/utils.py
@@ -1,5 +1,8 @@
 from django.db import models
 from django.contrib.contenttypes.models import ContentType
+from django.core.paginator import Paginator, EmptyPage
+from django.template import Context
+from django.template.loader_tags import ExtendsNode, ConstantIncludeNode
 
 
 class ContentTypeLimiter(object):
@@ -62,3 +65,90 @@ def fattr(*args, **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
+
+
+LOADED_TEMPLATE_ATTR = '_philo_loaded_template'
+BLANK_CONTEXT = Context()
+
+
+def get_extended(self):
+       return self.get_parent(BLANK_CONTEXT)
+
+
+def get_included(self):
+       return self.template
+
+
+# We ignore the IncludeNode because it will never work in a blank context.
+setattr(ExtendsNode, LOADED_TEMPLATE_ATTR, property(get_extended))
+setattr(ConstantIncludeNode, LOADED_TEMPLATE_ATTR, property(get_included))
+
+
+def default_callback(node, result_list):
+       result_list.append(node)
+       
+       if hasattr(node, 'child_nodelists'):
+               for nodelist_name in node.child_nodelists:
+                       if hasattr(node, nodelist_name):
+                               nodelist_crawl(getattr(node, nodelist_name), default_callback)
+       
+       # LOADED_TEMPLATE_ATTR contains the name of an attribute philo uses to declare a
+       # node as rendering an additional template. Philo monkeypatches the attribute onto
+       # the relevant default nodes and declares it on any native nodes.
+       if hasattr(node, LOADED_TEMPLATE_ATTR):
+               loaded_template = getattr(node, LOADED_TEMPLATE_ATTR)
+               if loaded_template:
+                       nodelist_crawl(loaded_template.nodelist, default_callback)
+
+
+def nodelist_crawl(nodelist, callback=default_callback, *args, **kwargs):
+       """This function crawls through a template's nodelist and the
+       nodelists of any included or extended templates, as determined by
+       the presence and value of <LOADED_TEMPLATE_ATTR> on a node. Each
+       node will also be passed to a callback function for additional
+       processing, along with any additional args and kwargs."""
+       for node in nodelist:
+               try:
+                       callback(node, *args, **kwargs)
+               except:
+                       raise # fail for this node
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