driver: break up cache drivers

inc/Data/Driver/CacheDriver.php

@@ -0,0 +1,38 @@
+<?php
+namespace Vichan\Data\Driver;
+
+defined('TINYBOARD') or exit;
+
+
+interface CacheDriver {
+	/**
+	 * Get the value of associated with the key.
+	 *
+	 * @param string $key The key of the value.
+	 * @return mixed|null The value associated with the key, or null if there is none.
+	 */
+	public function get(string $key): mixed;
+
+	/**
+	 * Set a key-value pair.
+	 *
+	 * @param string $key The key.
+	 * @param mixed $value The value.
+	 * @param int|false $expires After how many seconds the pair will expire. Use false or ignore this parameter to keep
+	 *                           the value until it gets evicted to make space for more items. Some drivers will always
+	 *                           ignore this parameter and store the pair until it's removed.
+	 */
+	public function set(string $key, mixed $value, mixed $expires = false): void;
+
+	/**
+	 * Delete a key-value pair.
+	 *
+	 * @param string $key The key.
+	 */
+	public function delete(string $key): void;
+
+	/**
+	 * Delete all the key-value pairs.
+	 */
+	public function flush(): void;
+}