Merge branch 'MDL-69772-master-allcountrycodes' of git://github.com/mudrd8mz/moodle into master

lib/adminlib.php

@@ -4947,6 +4947,66 @@ class admin_setting_langlist extends admin_setting_configtext {
 }
 
 
+/**
+ * Allows to specify comma separated list of known country codes.
+ *
+ * This is a simple subclass of the plain input text field with added validation so that all the codes are actually
+ * known codes.
+ *
+ * @package     core
+ * @category    admin
+ * @copyright   2020 David Mudrák <david@moodle.com>
+ * @license     https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class admin_setting_countrycodes extends admin_setting_configtext {
+
+    /**
+     * Construct the instance of the setting.
+     *
+     * @param string $name Name of the admin setting such as 'allcountrycodes' or 'myplugin/countries'.
+     * @param lang_string|string $visiblename Language string with the field label text.
+     * @param lang_string|string $description Language string with the field description text.
+     * @param string $defaultsetting Default value of the setting.
+     * @param int $size Input text field size.
+     */
+    public function __construct($name, $visiblename, $description, $defaultsetting = '', $size = null) {
+        parent::__construct($name, $visiblename, $description, $defaultsetting, '/^(?:\w+(?:,\w+)*)?$/', $size);
+    }
+
+    /**
+     * Validate the setting value before storing it.
+     *
+     * The value is first validated through custom regex so that it is a word consisting of letters, numbers or underscore; or
+     * a comma separated list of such words.
+     *
+     * @param string $data Value inserted into the setting field.
+     * @return bool|string True if the value is OK, error string otherwise.
+     */
+    public function validate($data) {
+
+        $parentcheck = parent::validate($data);
+
+        if ($parentcheck !== true) {
+            return $parentcheck;
+        }
+
+        if ($data === '') {
+            return true;
+        }
+
+        $allcountries = get_string_manager()->get_list_of_countries(true);
+
+        foreach (explode(',', $data) as $code) {
+            if (!isset($allcountries[$code])) {
+                return get_string('invalidcountrycode', 'core_error', $code);
+            }
+        }
+
+        return true;
+    }
+}
+
+
 /**
  * Selection of one of the recognised countries using the list
  * returned by {@link get_list_of_countries()}.