API Move logic from silverstripe/cms into central place

src/ORM/Hierarchy/Hierarchy.php

@@ -617,6 +617,30 @@ public function showingCMSTree()
             && in_array($controller->getAction(), ["treeview", "listview", "getsubtree"]);
     }
 
+    /**
+     * Return the CSS classes to apply to this node in the CMS tree.
+     */
+    public function CMSTreeClasses(): string
+    {
+        $owner = $this->getOwner();
+        $classes = sprintf('class-%s', Convert::raw2htmlid(get_class($owner)));
+
+        if (!$owner->canAddChildren()) {
+            $classes .= " nochildren";
+        }
+
+        if (!$owner->canEdit() && !$owner->canAddChildren()) {
+            if (!$owner->canView()) {
+                $classes .= " disabled";
+            } else {
+                $classes .= " edit-disabled";
+            }
+        }
+
+        $owner->invokeWithExtensions('updateCMSTreeClasses', $classes);
+        return $classes;
+    }
+
     /**
      * Find the first class in the inheritance chain that has Hierarchy extension applied
      *
@@ -777,6 +801,17 @@ public function getBreadcrumbs($separator = ' » ')
         return implode($separator ?? '', $crumbs);
     }
 
+    /**
+     * Get the title that will be used in TreeDropdownField and other tree structures.
+     */
+    public function getTreeTitle(): string
+    {
+        $owner = $this->getOwner();
+        $title = $owner->MenuTitle ?: $owner->Title;
+        $owner->extend('updateTreeTitle', $title);
+        return $title ?? ''; // @TODO see if we need to escape this (it was escaped in Group and is in File too)
+    }
+
     /**
      * Get the name of the dedicated sort field, if there is one.
      */

src/Security/Group.php

@@ -494,16 +494,6 @@ public function stageChildren()
             ->sort('"Sort"');
     }
 
-    /**
-     * @return string
-     */
-    public function getTreeTitle()
-    {
-        $title = htmlspecialchars($this->Title ?? '', ENT_QUOTES);
-        $this->extend('updateTreeTitle', $title);
-        return $title;
-    }
-
     /**
      * Overloaded to ensure the code is always descent.
      *

src/Security/PermissionCheckable.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace SilverStripe\Security;
+
+/**
+ * Model with permissions that can be checked using PermissionChecker
+ */
+interface PermissionCheckable
+{
+    /**
+     * Get the permission checker for this model
+     */
+    public function getPermissionChecker(): PermissionChecker;
+}