Add Memcached caching layer

src/Socialbox/Classes/CacheLayer/MemcachedCacheLayer.php

@@ -0,0 +1,95 @@
+<?php
+
+namespace Socialbox\Classes\CacheLayer;
+
+use Memcached;
+use RuntimeException;
+use Socialbox\Abstracts\CacheLayer;
+
+class MemcachedCacheLayer extends CacheLayer
+{
+    private Memcached $memcached;
+
+    /**
+     * Memcached cache layer constructor.
+     *
+     * @param string $host The Memcached server host.
+     * @param int $port The Memcached server port.
+     */
+    public function __construct(string $host, int $port)
+    {
+        if (!extension_loaded('memcached'))
+        {
+            throw new RuntimeException('The Memcached extension is not loaded in your PHP environment.');
+        }
+
+        $this->memcached = new Memcached();
+        if (!$this->memcached->addServer($host, $port))
+        {
+            throw new RuntimeException('Failed to connect to the Memcached server.');
+        }
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function set(string $key, mixed $value, int $ttl = 0): bool
+    {
+        if (!$this->memcached->set($key, $value, $ttl))
+        {
+            throw new RuntimeException('Failed to set the value in the Memcached cache.');
+        }
+
+        return true;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function get(string $key): mixed
+    {
+        $result = $this->memcached->get($key);
+
+        if ($this->memcached->getResultCode() !== Memcached::RES_SUCCESS)
+        {
+            throw new RuntimeException('Failed to get the value from the Memcached cache.');
+        }
+
+        return $result;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function delete(string $key): bool
+    {
+        if (!$this->memcached->delete($key) && $this->memcached->getResultCode() !== Memcached::RES_NOTFOUND)
+        {
+            throw new RuntimeException('Failed to delete the value from the Memcached cache.');
+        }
+
+        return true;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function exists(string $key): bool
+    {
+        $this->memcached->get($key);
+        return $this->memcached->getResultCode() === Memcached::RES_SUCCESS;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function clear(): bool
+    {
+        if (!$this->memcached->flush())
+        {
+            throw new RuntimeException('Failed to clear the Memcached cache.');
+        }
+
+        return true;
+    }
+}