update Piwik to version 2.16 (fixes #91)

www/analytics/vendor/piwik/cache/src/Backend.php

@@ -0,0 +1,62 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link http://piwik.org
+ * @license http://www.gnu.org/licenses/lgpl-3.0.html LGPL v3 or later
+ *
+ */
+namespace Piwik\Cache;
+
+/**
+ * Backend interface
+ */
+interface Backend
+{
+    /**
+     * Fetches an entry from the cache.
+     *
+     * @param string $id The id of the cache entry to fetch.
+     *
+     * @return mixed The cached data or FALSE, if no cache entry exists for the given id.
+     */
+    public function doFetch($id);
+
+    /**
+     * Tests if an entry exists in the cache.
+     *
+     * @param string $id The cache id of the entry to check for.
+     *
+     * @return boolean TRUE if a cache entry exists for the given cache id, FALSE otherwise.
+     */
+    public function doContains($id);
+
+    /**
+     * Puts data into the cache.
+     *
+     * @param string $id       The cache id.
+     * @param mixed  $data     The cache entry/data.
+     * @param int    $lifeTime The cache lifetime.
+     *                         If != 0, sets a specific lifetime for this cache entry (0 => infinite lifeTime).
+     *
+     * @return boolean TRUE if the entry was successfully stored in the cache, FALSE otherwise.
+     */
+    public function doSave($id, $data, $lifeTime = 0);
+
+    /**
+     * Deletes a cache entry.
+     *
+     * @param string $id The cache id.
+     *
+     * @return boolean TRUE if the cache entry was successfully deleted, FALSE otherwise.
+     */
+    public function doDelete($id);
+
+    /**
+     * Flushes all cache entries from the cache.
+     *
+     * @return boolean
+     */
+    public function doFlush();
+
+}