MDL-62315 form: Implement the privacy API for core_form subsystem

Forms subsystem has no own database table. The only personal data is the
user preference 'filemanager_recentviewmode' that stores the view mode
of the file picker element.

It was discussed whether handling of this preference should be added
here into core_form, or rather into core_repository subsystem. The final
decision was to consider the preference as owned by the core_form
because it is affecting the display of a form element, not the
repository backend (even though the strings describing it had been put
into core_repository strings).

lang/en/form.php

@@ -61,6 +61,8 @@
 $string['passwordunmaskedithint'] = 'Edit password';
 $string['passwordunmaskrevealhint'] = 'Reveal';
 $string['passwordunmaskinstructions'] = 'Press enter to save changes';
+$string['privacy:metadata:preference:filemanager_recentviewmode'] = 'Recently selected view mode of the file picker element.';
+$string['privacy:preference:filemanager_recentviewmode'] = 'Your preferred way of displaying files in the file picker is: {$a}';
 $string['requiredelement'] = 'Required field';
 $string['security'] = 'Security';
 $string['selectallornone'] = 'Select all/none';

lib/form/classes/privacy/provider.php

@@ -0,0 +1,88 @@
+<?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/>.
+
+/**
+ * Provides {@link \core_form\privacy\provider} class.
+ *
+ * @package     core_form
+ * @category    privacy
+ * @copyright   2018 David Mudrák <david@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_form\privacy;
+
+use core_privacy\local\metadata\collection;
+use core_privacy\local\request\writer;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Implements the privacy API for the core_form subsystem.
+ *
+ * @package   core_files
+ * @copyright 2018 David Mudrák <david@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class provider implements
+        // The forms subsystem does not store any data itself, it has no database tables.
+        \core_privacy\local\metadata\provider,
+
+        // The forms subsystem has user preferences.
+        \core_privacy\local\request\user_preference_provider {
+
+    /**
+     * Returns meta data about this system.
+     *
+     * @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->add_user_preference('filemanager_recentviewmode', 'privacy:metadata:preference:filemanager_recentviewmode');
+
+        return $collection;
+    }
+
+    /**
+     * Export all user preferences for the subsystem.
+     *
+     * @param int $userid The ID of the user whose data is to be exported.
+     */
+    public static function export_user_preferences($userid) {
+
+        $preference = get_user_preferences('filemanager_recentviewmode');
+
+        if ($preference !== null) {
+            switch ($preference) {
+                case 1:
+                    $value = get_string('displayasicons', 'core_repository');
+                    break;
+                case 2:
+                    $value = get_string('displayastree', 'core_repository');
+                    break;
+                case 3:
+                    $value = get_string('displaydetails', 'core_repository');
+                    break;
+                default:
+                    $value = $preference;
+            }
+
+            $desc = get_string('privacy:preference:filemanager_recentviewmode', 'core_form', $value);
+            writer::export_user_preference('core_form', 'filemanager_recentviewmode', $preference, $desc);
+        }
+    }
+}

lib/form/tests/privacy_provider_test.php

@@ -0,0 +1,100 @@
+<?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/>.
+
+/**
+ * Provides the {@link core_form_privacy_provider_testcase} class.
+ *
+ * @package     core_form
+ * @category    test
+ * @copyright   2018 David Mudrák <david@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+use core_privacy\local\request\writer;
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Unit tests for the privacy API implementation.
+ *
+ * @copyright 2018 David Mudrák <david@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class core_form_privacy_provider_testcase extends \core_privacy\tests\provider_testcase {
+
+    /**
+     * When no preference exists, there should be no export.
+     */
+    public function test_no_preference() {
+        global $USER;
+        $this->resetAfterTest();
+        $this->setAdminUser();
+
+        \core_form\privacy\provider::export_user_preferences($USER->id);
+        $this->assertFalse(writer::with_context(\context_system::instance())->has_any_data());
+    }
+
+    /**
+     * Test that the recently selected filepicker view mode is exported.
+     *
+     * @dataProvider data_filemanager_recentviewmode
+     * @param string $val Value of the preference filemanager_recentviewmode
+     * @param string $desc Text describing the preference
+     */
+    public function test_filemanager_recentviewmode($val, $desc) {
+        global $USER;
+        $this->resetAfterTest();
+        $this->setAdminUser();
+
+        set_user_preference('filemanager_recentviewmode', $val);
+
+        core_form\privacy\provider::export_user_preferences($USER->id);
+        $this->assertTrue(writer::with_context(\context_system::instance())->has_any_data());
+
+        $prefs = writer::with_context(\context_system::instance())->get_user_preferences('core_form');
+        $this->assertNotEmpty($prefs->filemanager_recentviewmode);
+        $this->assertNotEmpty($prefs->filemanager_recentviewmode->value);
+        $this->assertNotEmpty($prefs->filemanager_recentviewmode->description);
+        $this->assertEquals($val, $prefs->filemanager_recentviewmode->value);
+        $this->assertContains($desc, $prefs->filemanager_recentviewmode->description);
+    }
+
+    /**
+     * Provides data for the {@link self::test_filemanager_recentviewmode()} method.
+     *
+     * @return array
+     */
+    public function data_filemanager_recentviewmode() {
+        return [
+            'icons' => [
+                'val' => '1',
+                'desc' => get_string('displayasicons', 'core_repository'),
+            ],
+            'tree' => [
+                'val' => '2',
+                'desc' => get_string('displayastree', 'core_repository'),
+            ],
+            'details' => [
+                'val' => '3',
+                'desc' => get_string('displaydetails', 'core_repository'),
+            ],
+            'unknown' => [
+                'val' => 'unexpectedvalue_foo_bar',
+                'desc' => 'unexpectedvalue_foo_bar',
+            ],
+        ];
+    }
+}