MDL-61898 core_cache: Implement Privacy API

cache/classes/privacy/provider.php

@@ -0,0 +1,66 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle 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 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Privacy Subsystem implementation for core_cache.
+ *
+ * @package    core_cache
+ * @copyright  2018 Andrew Nicols <[email protected]>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_cache\privacy;
+
+defined('MOODLE_INTERNAL') || die();
+
+use \core_privacy\local\metadata\collection;
+
+/**
+ * Privacy Subsystem implementation for core_cache.
+ *
+ * @copyright  2018 Andrew Nicols <[email protected]>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class provider implements
+        // Caches store data.
+        \core_privacy\local\metadata\provider,
+
+        // The cache subsystem stores data on behalf of other components.
+        \core_privacy\local\request\subsystem\plugin_provider {
+
+    /**
+     * Returns meta data about this system.
+     *
+     * Note, although this plugin does store user data, it is not able to
+     * identify it, and that user data is typically very short lived.
+     *
+     * Therefore it is not realistically possible to export any of this
+     * data as it is only identifiable by the plugin storing it, and that
+     * plugin should already be exporting the data as part of it's own
+     * implementation.
+     *
+     * @param   collection     $collection The initialised collection to add items to.
+     * @return  collection     A listing of user data stored through this system.
+     */
+    public static function get_metadata(collection $collection) : collection {
+        // Data is stored in cache stores.
+        $collection->add_plugintype_link('cachestore', [], 'privacy:metadata:cachestore');
+
+        // Cache locks do not store any personal user data.
+
+        return $collection;
+    }
+}

lang/en/cache.php

@@ -137,6 +137,7 @@
 $string['none'] = 'None';
 $string['plugin'] = 'Plugin';
 $string['pluginsummaries'] = 'Installed cache stores';
+$string['privacy:metadata:cachestore'] = 'The Cache subsystem stores data temporarily on behalf of other parts of Moodle. This data is not easily identifiable, and is very short lived. It serves as a cache of data stored elsewhere in Moodle, and should therefore already be handled by those Moodle components.';
 $string['purge'] = 'Purge';
 $string['purgedefinitionsuccess'] = 'Successfully purged the requested definition.';
 $string['purgestoresuccess'] = 'Successfully purged the requested store.';