Merge branch 'release/0.9.1'

[philo.git] / philo / utils / templates.py

diff --git a/philo/utils/templates.py b/philo/utils/templates.py
new file mode 100644 (file)
index 0000000..e0be31f
--- /dev/null
+++ b/philo/utils/templates.py
@@ -0,0 +1,123 @@
+import itertools
+
+from django.template import TextNode, VariableNode, Context
+from django.template.loader_tags import BlockNode, ExtendsNode, BlockContext, ConstantIncludeNode
+from django.utils.datastructures import SortedDict
+
+from philo.templatetags.containers import ContainerNode
+
+
+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 get_containers(template):
+               # Build a tree of the templates we're using, placing the root template first.
+               levels = build_extension_tree(template.nodelist)
+               
+               contentlet_specs = []
+               contentreference_specs = SortedDict()
+               blocks = {}
+               
+               for level in reversed(levels):
+                       level.initialize()
+                       contentlet_specs.extend(itertools.ifilter(lambda x: x not in contentlet_specs, level.contentlet_specs))
+                       contentreference_specs.update(level.contentreference_specs)
+                       for name, block in level.blocks.items():
+                               if block.block_super:
+                                       blocks.setdefault(name, []).append(block)
+                               else:
+                                       blocks[name] = [block]
+               
+               for block_list in blocks.values():
+                       for block in block_list:
+                               block.initialize()
+                               contentlet_specs.extend(itertools.ifilter(lambda x: x not in contentlet_specs, block.contentlet_specs))
+                               contentreference_specs.update(block.contentreference_specs)
+               
+               return contentlet_specs, contentreference_specs
+
+
+class LazyContainerFinder(object):
+       def __init__(self, nodes, extends=False):
+               self.nodes = nodes
+               self.initialized = False
+               self.contentlet_specs = []
+               self.contentreference_specs = SortedDict()
+               self.blocks = {}
+               self.block_super = False
+               self.extends = extends
+       
+       def process(self, nodelist):
+               for node in nodelist:
+                       if self.extends:
+                               if isinstance(node, BlockNode):
+                                       self.blocks[node.name] = block = LazyContainerFinder(node.nodelist)
+                                       block.initialize()
+                                       self.blocks.update(block.blocks)
+                               continue
+                       
+                       if isinstance(node, ContainerNode):
+                               if not node.references:
+                                       self.contentlet_specs.append(node.name)
+                               else:
+                                       if node.name not in self.contentreference_specs.keys():
+                                               self.contentreference_specs[node.name] = node.references
+                               continue
+                       
+                       if isinstance(node, VariableNode):
+                               if node.filter_expression.var.lookups == (u'block', u'super'):
+                                       self.block_super = True
+                       
+                       if hasattr(node, 'child_nodelists'):
+                               for nodelist_name in node.child_nodelists:
+                                       if hasattr(node, nodelist_name):
+                                               nodelist = getattr(node, nodelist_name)
+                                               self.process(nodelist)
+                       
+                       # 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 = loaded_template.nodelist
+                                       self.process(nodelist)
+       
+       def initialize(self):
+               if not self.initialized:
+                       self.process(self.nodes)
+                       self.initialized = True
+
+
+def build_extension_tree(nodelist):
+       nodelists = []
+       extends = None
+       for node in nodelist:
+               if not isinstance(node, TextNode):
+                       if isinstance(node, ExtendsNode):
+                               extends = node
+                       break
+       
+       if extends:
+               if extends.nodelist:
+                       nodelists.append(LazyContainerFinder(extends.nodelist, extends=True))
+               loaded_template = getattr(extends, LOADED_TEMPLATE_ATTR)
+               nodelists.extend(build_extension_tree(loaded_template.nodelist))
+       else:
+               # Base case: root.
+               nodelists.append(LazyContainerFinder(nodelist))
+       return nodelists
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