Add PSR-16 compatible adapter

composer.json

@@ -19,7 +19,8 @@
         "doctrine/cache": "~1.0"
     },
     "suggest": {
-        "psr/cache-implementation": "To make use of PSR-6 cache implementation via PsrCacheAdapter."
+        "psr/cache-implementation": "To make use of PSR-6 cache implementation via PsrCacheAdapter.",
+        "psr/simple-cache-implementation": "To make use of PSR-16 cache implementation via PsrSimpleCacheAdapter."
     },
     "autoload": {
         "psr-4": {

lib/Asm89/Twig/CacheExtension/CacheProvider/PsrSimpleCacheAdapter.php

@@ -0,0 +1,110 @@
+<?php
+
+/*
+ * This file is part of twig-cache-extension.
+ *
+ * (c) Alexander <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Asm89\Twig\CacheExtension\CacheProvider;
+
+/**
+ * Adapter class to make the Asm89 Twig caching extension interoperable with every PSR-16 adapter.
+ *
+ * @see http://www.php-fig.org/psr/psr-16/
+ *
+ * @author Heino H. Gehlsen <[email protected]>
+ * @copyright 2017 Heino H. Gehlsen
+ * @license MIT
+ */
+class PsrSimpleCacheAdapter
+	implements \Asm89\Twig\CacheExtension\CacheProviderInterface
+{
+    /**
+     * @var \Psr\SimpleCache\CacheInterface
+     */
+    private $cache;
+
+    /**
+     * @var \Psr\SimpleCache\CacheException
+     */
+    private $lastException;
+
+    /**
+     * @param \Psr\SimpleCache\CacheInterface $cache
+     */
+    public function __construct(\Psr\SimpleCache\CacheInterface $cache)
+    {
+        $this->cache = $cache;
+    }
+
+    /**
+     * @param string $key
+     * @return mixed|false False, if there was no value to be fetched. Null or a string otherwise.
+     */
+    public function fetch($key)
+    {
+		// Reset last exception
+		$this->lastException = null;
+
+		try {
+			// Get value from implementing library. Return false if there was no value to be fetched
+			$value = $this->cache->get($key, false);
+
+			// Return cached value
+			return $value;
+
+		// "Exception interface for invalid cache arguments."
+		} catch (\Psr\SimpleCache\InvalidArgumentException $e) {
+			// Save exception for retrieval by caller 
+			$this->lastException = $e;
+			// Return fail to caller
+			return false;
+
+		// "Interface used for all types of exceptions thrown by the implementing library."
+		} catch (\Psr\SimpleCache\CacheException $e) {
+			// Save exception for retrieval by caller 
+			$this->lastException = $e;
+			// Return fail to caller
+			return false;
+		}
+	}
+
+    /**
+     * @param string  $key
+     * @param string  $value
+     * @param integer $lifetime
+     *
+     * @return bool
+     */
+    public function save($key, $value, $lifetime = 0)
+    {
+		// Reset last exception
+		$this->lastException = null;
+
+		try {
+			// Send value to implementing library.
+			$success = $this->cache->set($key, $value, $lifetime);
+
+			// Return boolean from implementing library.
+			return $success;
+
+		// "Exception interface for invalid cache arguments."
+		} catch (\Psr\SimpleCache\InvalidArgumentException $e) {
+			// Save exception for retrieval by caller 
+			$this->lastException = $e;
+			// Return fail to caller
+			return false;
+
+		// "Interface used for all types of exceptions thrown by the implementing library."
+		} catch (\Psr\SimpleCache\CacheException $e) {
+			// Save exception for retrieval by caller 
+			$this->lastException = $e;
+			// Return fail to caller
+			return false;
+		}
+    }
+}