perfs: limit cells considered for cell.modify_global_context (#21052)

combo/data/models.py

@@ -356,6 +356,10 @@ class CellBase(models.Model):
     # get_badge(self, context); set to None so cell types can be skipped easily
     get_badge = None
 
+    # modify_global_context(self, context, request=None)
+    # Apply changes to the template context that must visible to all cells in the page
+    modify_global_context = None
+
     class Meta:
         abstract = True
 
@@ -526,10 +530,6 @@ class CellBase(models.Model):
         tmpl = template.loader.select_template(template_names)
         return tmpl.render(context, context.get('request'))
 
-    def modify_global_context(self, context, request=None):
-        '''Apply changes to the template context that must visible to all cells in the page'''
-        return context
-
     def render_for_search(self):
         if not self.is_enabled():
             return ''

combo/public/views.py

@@ -112,12 +112,15 @@ def render_cell(request, cell):
     }
 
     if cell.page_id:
-        other_cells = CellBase.get_cells(page_id=cell.page_id)
+        other_cells = []
+        for klass in CellBase.get_cell_classes(lambda x: bool(x.modify_global_context)):
+            other_cells.extend(klass.objects.filter(page_id=cell.page_id))
         other_cells = [x for x in other_cells if x.is_visible(user=request.user)]
+        other_cells.sort(key=lambda x: x.order)
         for other_cell in other_cells:
             if other_cell.get_reference() != cell.get_reference():
                 other_cell.modify_global_context(context, request)
-            else:
+            elif cell.modify_global_context:
                 # Cell can pass data through its own __dict__
                 cell.modify_global_context(context, request)
 
@@ -370,7 +373,8 @@ def publish_page(request, page, status=200, template_name=None):
     }
 
     for cell in cells:
-        cell.modify_global_context(ctx, request)
+        if cell.modify_global_context:
+            cell.modify_global_context(ctx, request)
 
     if not template_name:
         combo_template = settings.COMBO_PUBLIC_TEMPLATES[page.template_name]