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system/View/ViewDecoratorTrait.php

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+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\View;
+
+use CodeIgniter\View\Exceptions\ViewException;
+use Config\View as ViewConfig;
+
+trait ViewDecoratorTrait
+{
+    /**
+     * Runs the generated output through any declared
+     * view decorators.
+     */
+    protected function decorateOutput(string $html): string
+    {
+        $decorators = $this->config->decorators ?? config(ViewConfig::class)->decorators;
+
+        foreach ($decorators as $decorator) {
+            if (! is_subclass_of($decorator, ViewDecoratorInterface::class)) {
+                throw ViewException::forInvalidDecorator($decorator);
+            }
+
+            $html = $decorator::decorate($html);
+        }
+
+        return $html;
+    }
+}