Cache tree structure in loops

integreat_cms/cms/models/abstract_tree_node.py

@@ -3,11 +3,85 @@
 from django.utils.translation import ugettext_lazy as _
 
 from treebeard.exceptions import InvalidPosition
-from treebeard.ns_tree import NS_Node, get_result_class
+from treebeard.ns_tree import NS_Node, NS_NodeQuerySet, get_result_class
 
 logger = logging.getLogger(__name__)
 
 
+class TreeNodeQuerySet(NS_NodeQuerySet):
+    """
+    This queryset provides custom caching mechanisms for trees
+    """
+
+    def cache_tree(self):
+        """
+        Caches a tree queryset in a python data structure.
+
+        :return: A list of tree nodes with cached children, descendants and ancestors
+        :rtype: list
+        """
+        result = {}
+        for node in self.order_by("tree_id", "lft"):
+            # Only include the element in the tree if it is either a root node or the parent is contained in the set
+            if not node.parent_id or node.parent_id in result:
+                if node.parent_id:
+                    # Cache the node as child of the parent node
+                    # pylint: disable=protected-access
+                    result[node.parent_id]._cached_children.append(node)
+                    result[node.parent_id]._cached_descendants.append(node)
+                    # Cache the parent node as ancestor of the current node
+                    node._cached_ancestors.extend(
+                        result[node.parent_id]._cached_ancestors
+                    )
+                    node._cached_ancestors.append(result[node.parent_id])
+                    # Cache the current node as descendant of the parent's node ancestors
+                    for ancestor in result[node.parent_id]._cached_ancestors:
+                        result[ancestor.id]._cached_descendants.append(node)
+                # Mark as initialized to know the difference between no children and no cache
+                # pylint: disable=protected-access
+                node._cache_initialized = True
+                result[node.id] = node
+                logger.debug("Node %r cached", node)
+            else:
+                logger.debug("Node %r skipped", node)
+        logger.debug("Cached result: %r", result)
+        return list(result.values())
+
+    def prefetch_ancestors(self):
+        """
+        Prefetches all ancestors of a tree nodes
+
+        :return: The queryset of tree nodes
+        :rtype: ~integreat_cms.cms.models.abstract_tree_node.TreeNodeQuerySet [ ~integreat_cms.cms.models.abstract_tree_node.AbstractTreeNode ]
+        """
+        model = get_result_class(self.model)
+        return self.annotate(
+            prefetched_ancestors=models.Subquery(
+                model.filter(
+                    tree_id=models.OuterRef("tree_id"),
+                    lft__lte=models.OuterRef("lft"),
+                    rgt__gte=models.OuterRef("rgt"),
+                )
+            )
+        )
+
+
+# pylint: disable=too-few-public-methods
+class TreeNodeManager(models.Manager):
+    """
+    Custom manager for this queryset
+    """
+
+    def get_queryset(self):
+        """
+        Get the queryset of tree nodes
+
+        :return: The queryset of tree nodes
+        :rtype: ~integreat_cms.cms.models.abstract_tree_node.TreeNodeQuerySet [ ~integreat_cms.cms.models.abstract_tree_node.AbstractTreeNode ]
+        """
+        return TreeNodeQuerySet(self.model).order_by("tree_id", "lft")
+
+
 class AbstractTreeNode(NS_Node):
     """
     Abstract data model representing a tree node within a region.
@@ -29,6 +103,16 @@ class AbstractTreeNode(NS_Node):
         verbose_name=_("region"),
     )
 
+    #: Custom model manager :class:`~integreat_cms.cms.models.abstract_tree_node.TreeNodeManager` for tree objects
+    objects = TreeNodeManager()
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._cache_initialized = False
+        self._cached_children = []
+        self._cached_descendants = []
+        self._cached_ancestors = []
+
     def save(self, *args, **kwargs):
         # Update parent to fix inconsistencies between tree fields
         if self.id:
@@ -135,12 +219,31 @@ def get_ancestors(self, include_self=False):
                  the root node and descending to the parent.
         :rtype: ~treebeard.ns_tree.NS_NodeQuerySet
         """
+        if self._cache_initialized:
+            return self.get_cached_ancestors(include_self=include_self)
         if include_self:
             return get_result_class(self.__class__).objects.filter(
                 tree_id=self.tree_id, lft__lte=self.lft, rgt__gte=self.rgt
             )
         return super().get_ancestors()
 
+    def get_cached_ancestors(self, include_self=False):
+        """
+        Get the cached ancestors of a specific node
+
+        :param include_self: Whether the current node should be included in the result (defaults to ``False``)
+        :type include_self: bool
+
+        :return: A :class:`~django.db.models.query.QuerySet` containing the current node object's ancestors, starting by
+                 the root node and descending to the parent.
+        :rtype: ~treebeard.ns_tree.NS_NodeQuerySet
+        """
+        if not self._cache_initialized:
+            return self.get_ancestors(include_self=include_self)
+        if include_self:
+            return [*self._cached_ancestors, self]
+        return self._cached_ancestors
+
     # pylint: disable=arguments-differ
     def get_descendants(self, include_self=False):
         """
@@ -152,13 +255,54 @@ def get_descendants(self, include_self=False):
         :return: A :class:`~django.db.models.query.QuerySet` of all the node's descendants as DFS
         :rtype: ~treebeard.ns_tree.NS_NodeQuerySet
         """
+        if self._cache_initialized:
+            return self.get_cached_descendants(include_self=include_self)
         if self.is_leaf():
             return get_result_class(self.__class__).objects.none()
         tree = self.__class__.get_tree(parent=self)
         if include_self:
             return tree
         return tree.exclude(pk=self.pk)
 
+    def get_cached_descendants(self, include_self=False):
+        """
+        Get the cached ancestors of a specific node
+
+        :param include_self: Whether the current node should be included in the result (defaults to ``False``)
+        :type include_self: bool
+
+        :return: A :class:`~django.db.models.query.QuerySet` containing the current node object's ancestors, starting by
+                 the root node and descending to the parent.
+        :rtype: ~treebeard.ns_tree.NS_NodeQuerySet
+        """
+        if not self._cache_initialized:
+            return self.get_descendants(include_self=include_self)
+        if include_self:
+            return [*self._cached_descendants, self]
+        return self._cached_descendants
+
+    def get_children(self):
+        """
+        A wrapper around get_children() to make use of cached children
+
+        :returns: A queryset or list of all the node's children
+        :rtype: list
+        """
+        if self._cache_initialized:
+            return self.get_cached_children()
+        return super().get_children()
+
+    def get_cached_children(self):
+        """
+        Get all cached children
+
+        :returns: A list of all the node's cached children
+        :rtype: list
+        """
+        if not self._cache_initialized:
+            return self.get_children()
+        return self._cached_children
+
     def move(self, target, pos=None):
         """
         Moves the current node and all it's descendants to a new position

integreat_cms/cms/models/pages/abstract_base_page.py

@@ -198,7 +198,7 @@ def get_translation_state(self, language):
             return translation_status.MISSING
         if translation.currently_in_translation:
             return translation_status.IN_TRANSLATION
-        source_language = self.region.language_tree_by_id.get(language.parent_id)
+        source_language = self.region.language_node_by_id.get(language.parent_id)
         if not source_language:
             return translation_status.UP_TO_DATE
         source_translation = self.get_public_translation(source_language.slug)

integreat_cms/cms/templates/language_tree/language_tree_node.html

@@ -6,7 +6,7 @@
 {% endif %}
 <tr data-drop-id="{{ node.id }}" data-drop-position="last-child" class="drop drop-on border-t border-b border-solid border-gray-200 hover:bg-gray-100{% if node.depth > 1 %} child level-{{node.depth}}{% endif %}">
     <td class="hierarchy single_icon">
-		<span data-drag-id="{{ node.id }}" data-node-descendants="{{ node|get_descendants }}" class="drag text-gray-800 block py-3 pl-4 pr-2 cursor-move" draggable="true">
+		<span data-drag-id="{{ node.id }}" data-node-descendants="{{ node|get_descendant_ids }}" class="drag text-gray-800 block py-3 pl-4 pr-2 cursor-move" draggable="true">
             <i data-feather="move" class="text-gray-800"></i>
         </span>
     </td>

integreat_cms/cms/templates/pages/page_form.html

@@ -354,7 +354,7 @@ <h1 class="heading">
                                 <div class="bg-orange-100 border-l-4 border-orange-500 text-orange-500 px-4 py-3 mb-5" role="alert">
                                     <p>
                                         {% trans 'You cannot delete a page which has subpages.' %}<br>
-                                        {% blocktrans count counter=page.get_descendants.count trimmed %}
+                                        {% blocktrans count counter=page.get_descendants|length trimmed %}
                                             To delete this page, you have to delete or move its subpage first:
                                         {% plural %}
                                             To delete this page, you have to delete or move its subpages first:

integreat_cms/cms/templates/pages/page_tree_node.html

@@ -11,7 +11,7 @@
     </td>
     <td class="hierarchy single_icon whitespace-nowrap">
         <span data-drag-id="{{ page.id }}"
-              data-node-descendants="{{ page|get_descendants }}"
+              data-node-descendants="{{ page|get_descendant_ids }}"
               class="{% if enable_drag_and_drop %}drag cursor-move{% else %}cursor-not-allowed{% endif %} text-gray-800 inline-block pl-4 align-middle"
               {% if enable_drag_and_drop %}
               draggable="true"
@@ -25,7 +25,7 @@
         <span class="collapse-subpages cursor-pointer inline-block align-middle"
               title="{% trans 'Collapse all subpages' %}"
               data-page-id="{{ page.id }}"
-              data-page-children="{{ page|get_children }}">
+              data-page-children="{{ page|get_children_ids }}">
                 <i data-feather="chevron-right"></i>
             </span>
         {% endif %}

integreat_cms/cms/templatetags/tree_filters.py

@@ -10,7 +10,7 @@
 
 
 @register.filter
-def get_descendants(node):
+def get_descendant_ids(node):
     """
     This filter returns the ids of all the node's descendants.
 
@@ -24,7 +24,7 @@ def get_descendants(node):
 
 
 @register.filter
-def get_children(node):
+def get_children_ids(node):
     """
     This filter returns the ids of all the node's direct children.
 

integreat_cms/cms/views/pages/page_tree_view.py

@@ -155,7 +155,7 @@ def page_filter(page):
             {
                 **context,
                 "current_menu_item": "pages",
-                "pages": pages,
+                "pages": pages.cache_tree(),
                 "archived_count": region.get_pages(archived=True).count(),
                 "language": language,
                 "languages": region.active_languages,

integreat_cms/locale/de/LC_MESSAGES/django.po

@@ -1818,11 +1818,11 @@ msgstr "Sie haben Ihr bisheriges Passwort falsch eingegeben."
 msgid "The new passwords do not match."
 msgstr "Die Passwörter stimmen nicht überein."
 
-#: cms/models/abstract_tree_node.py:24
+#: cms/models/abstract_tree_node.py:98
 msgid "parent"
 msgstr "übergeordneter Knoten"
 
-#: cms/models/abstract_tree_node.py:29 cms/models/events/event.py:82
+#: cms/models/abstract_tree_node.py:103 cms/models/events/event.py:82
 #: cms/models/feedback/feedback.py:22 cms/models/media/directory.py:23
 #: cms/models/media/media_file.py:135 cms/models/pages/imprint_page.py:22
 #: cms/models/pois/poi.py:20
@@ -1831,7 +1831,7 @@ msgstr "übergeordneter Knoten"
 msgid "region"
 msgstr "Region"
 
-#: cms/models/abstract_tree_node.py:178
+#: cms/models/abstract_tree_node.py:322
 msgid "The node \"{}\" in region \"{}\" cannot be moved to \"{}\"."
 msgstr ""
 "Der Knoten \"{}\" in Region \"{}\" kann nicht nach \"{}\" verschoben werden."