refacor: improve cache interface (#3492)

* fix: proper typehint on setScope

* refactor: type hint setKey()

* typehint

lib/CacheInterface.php

@@ -1,68 +1,16 @@
 <?php
 
-/**
- * This file is part of RSS-Bridge, a PHP project capable of generating RSS and
- * Atom feeds for websites that don't have one.
- *
- * For the full license information, please view the UNLICENSE file distributed
- * with this source code.
- *
- * @package Core
- * @license http://unlicense.org/ UNLICENSE
- * @link    https://github.com/rss-bridge/rss-bridge
- */
-
-/**
- * The cache interface
- */
 interface CacheInterface
 {
-    /**
-     * Set scope of the current cache
-     *
-     * If $scope is an empty string, the cache is set to a global context.
-     *
-     * @param string $scope The scope the data is related to
-     */
-    public function setScope($scope);
+    public function setScope(string $scope): void;
 
-    /**
-     * Set key to assign the current data
-     *
-     * Since $key can be anything, the cache implementation must ensure to
-     * assign the related data reliably; most commonly by serializing and
-     * hashing the key in an appropriate way.
-     *
-     * @param array $key The key the data is related to
-     */
-    public function setKey($key);
+    public function setKey(array $key): void;
 
-    /**
-     * Loads data from cache
-     *
-     * @return mixed The cached data or null
-     */
     public function loadData();
 
-    /**
-     * Stores data to the cache
-     *
-     * @param mixed $data The data to store
-     * @return self The cache object
-     */
-    public function saveData($data);
+    public function saveData($data): void;
 
-    /**
-     * Returns the modification time of the current cache item.
-     * In unix timestamp.
-     * Example: 1688570578
-     */
     public function getTime(): ?int;
 
-    /**
-     * Removes any data that is older than the specified age from cache
-     *
-     * @param int $seconds The cache age in seconds
-     */
-    public function purgeCache($seconds);
+    public function purgeCache(int $seconds): void;
 }