+<?php
+/**
+ * Cache of various elements in a single cache entry.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @license GPL-2.0-or-later
+ * @author Jeroen De Dauw < jeroendedauw@gmail.com >
+ */
+
+/**
+ * Interface for all classes implementing CacheHelper functionality.
+ *
+ * @since 1.20
+ */
+interface ICacheHelper {
+ /**
+ * Sets if the cache should be enabled or not.
+ *
+ * @since 1.20
+ * @param bool $cacheEnabled
+ */
+ function setCacheEnabled( $cacheEnabled );
+
+ /**
+ * Initializes the caching.
+ * Should be called before the first time anything is added via addCachedHTML.
+ *
+ * @since 1.20
+ *
+ * @param int|null $cacheExpiry Sets the cache expiry, either ttl in seconds or unix timestamp.
+ * @param bool|null $cacheEnabled Sets if the cache should be enabled or not.
+ */
+ function startCache( $cacheExpiry = null, $cacheEnabled = null );
+
+ /**
+ * Get a cached value if available or compute it if not and then cache it if possible.
+ * The provided $computeFunction is only called when the computation needs to happen
+ * and should return a result value. $args are arguments that will be passed to the
+ * compute function when called.
+ *
+ * @since 1.20
+ *
+ * @param callable $computeFunction
+ * @param array|mixed $args
+ * @param string|null $key
+ *
+ * @return mixed
+ */
+ function getCachedValue( $computeFunction, $args = [], $key = null );
+
+ /**
+ * Saves the HTML to the cache in case it got recomputed.
+ * Should be called after the last time anything is added via addCachedHTML.
+ *
+ * @since 1.20
+ */
+ function saveCache();
+
+ /**
+ * Sets the time to live for the cache, in seconds or a unix timestamp
+ * indicating the point of expiry...
+ *
+ * @since 1.20
+ *
+ * @param int $cacheExpiry
+ */
+ function setExpiry( $cacheExpiry );
+}