driver: break up cache drivers

inc/Data/Driver/ApcuCacheDriver.php

@@ -0,0 +1,28 @@
+<?php
+namespace Vichan\Data\Driver;
+
+defined('TINYBOARD') or exit;
+
+
+class ApcuCacheDriver implements CacheDriver {
+	public function get(string $key): mixed {
+		$success = false;
+		$ret = \apcu_fetch($key, $success);
+		if ($success === false) {
+			return null;
+		}
+		return $ret;
+	}
+
+	public function set(string $key, mixed $value, mixed $expires = false): void {
+		\apcu_store($key, $value, (int)$expires);
+	}
+
+	public function delete(string $key): void {
+		\apcu_delete($key);
+	}
+
+	public function flush(): void {
+		\apcu_clear_cache();
+	}
+}