new: [ACL Helper] check access for controller / action pair for given user

- accesible everywhere in the UI

src/View/AppView.php

@@ -44,5 +44,6 @@ class AppView extends View
         $this->loadHelper('FormFieldMassage');
         $this->loadHelper('Paginator', ['templates' => 'cerebrate-pagination-templates']);
         $this->loadHelper('Tags.Tag');
+        $this->loadHelper('ACL');
     }
 }

src/View/Helper/ACLHelper.php

@@ -0,0 +1,25 @@
+<?php
+namespace App\View\Helper;
+
+use Cake\View\Helper;
+
+// This helper helps determining the brightness of a colour (initially only used for the tagging) in order to decide
+// what text colour to use against the background (black or white)
+class ACLHelper extends Helper {
+
+    private $roleAccess = [];
+
+    public function checkAccess($controller, $action) {
+        if (empty($this->roleAccess)) {
+            $this->roleAccess = $this->getView()->get('roleAccess');
+        }
+        if (
+            in_array($action, $this->roleAccess['*']) ||
+            (isset($this->roleAccess[$controller]) && in_array($action, $this->roleAccess[$controller]))
+        ) {
+            return true;
+        } else {
+            return false;
+        }
+    }
+}