Initial

system/Cache/CacheFactory.php

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+<?php
+
+/**
+ * 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\Cache;
+
+use CodeIgniter\Cache\Exceptions\CacheException;
+use CodeIgniter\Exceptions\CriticalError;
+use CodeIgniter\Test\Mock\MockCache;
+use Config\Cache;
+
+/**
+ * A factory for loading the desired
+ */
+class CacheFactory
+{
+    /**
+     * The class to use when mocking
+     *
+     * @var string
+     */
+    public static $mockClass = MockCache::class;
+
+    /**
+     * The service to inject the mock as
+     *
+     * @var string
+     */
+    public static $mockServiceName = 'cache';
+
+    /**
+     * Attempts to create the desired cache handler, based upon the
+     *
+     * @return CacheInterface
+     */
+    public static function getHandler(Cache $config, ?string $handler = null, ?string $backup = null)
+    {
+        if (! isset($config->validHandlers) || ! is_array($config->validHandlers)) {
+            throw CacheException::forInvalidHandlers();
+        }
+
+        if (! isset($config->handler) || ! isset($config->backupHandler)) {
+            throw CacheException::forNoBackup();
+        }
+
+        $handler = ! empty($handler) ? $handler : $config->handler;
+        $backup  = ! empty($backup) ? $backup : $config->backupHandler;
+
+        if (! array_key_exists($handler, $config->validHandlers) || ! array_key_exists($backup, $config->validHandlers)) {
+            throw CacheException::forHandlerNotFound();
+        }
+
+        $adapter = new $config->validHandlers[$handler]($config);
+
+        if (! $adapter->isSupported()) {
+            $adapter = new $config->validHandlers[$backup]($config);
+
+            if (! $adapter->isSupported()) {
+                // Fall back to the dummy adapter.
+                $adapter = new $config->validHandlers['dummy']();
+            }
+        }
+
+        // If $adapter->initialization throws a CriticalError exception, we will attempt to
+        // use the $backup handler, if that also fails, we resort to the dummy handler.
+        try {
+            $adapter->initialize();
+        } catch (CriticalError $e) {
+            log_message('critical', $e->getMessage() . ' Resorting to using ' . $backup . ' handler.');
+
+            // get the next best cache handler (or dummy if the $backup also fails)
+            $adapter = self::getHandler($config, $backup, 'dummy');
+        }
+
+        return $adapter;
+    }
+}