Add FormFieldValidatorUtil

See #2545

diff --git a/wcfsetup/install/files/lib/system/form/builder/field/validation/FormFieldValidatorUtil.class.php b/wcfsetup/install/files/lib/system/form/builder/field/validation/FormFieldValidatorUtil.class.php
new file mode 100644 (file)
index 0000000..82a1d92
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/form/builder/field/validation/FormFieldValidatorUtil.class.php
@@ -0,0 +1,53 @@
+<?php
+namespace wcf\system\form\builder\field\validation;
+use wcf\system\form\builder\field\IFormField;
+use wcf\system\Regex;
+
+/**
+ * Contains form field validator-related functions.
+ * 
+ * @author     Matthias Schmidt
+ * @copyright  2001-2018 WoltLab GmbH
+ * @license    GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package    WoltLabSuite\Core\System\Form\Builder\Field\Validation
+ * @since      3.2
+ */
+abstract class FormFieldValidatorUtil {
+       /**
+        * Returns a form field validator to check the form field value against
+        * the given regular expression.
+        * 
+        * @param       string          $regularExpression      regular expression used to validate form field value
+        * @param       string          $languageItemPrefix     language item prefix used for error language item `{$languageItemPrefix}.error.format`
+        * @return      IFormFieldValidator
+        * 
+        * @throws      \InvalidArgumentException               if regular expression is invalid
+        */
+       public static function getRegularExpressionValidator(string $regularExpression, string $languageItemPrefix): IFormFieldValidator {
+               $regex = Regex::compile($regularExpression);
+               if (!$regex->isValid()) {
+                       throw new \InvalidArgumentException("Invalid regular expression '{$regularExpression}' given.");
+               }
+               
+               return new FormFieldValidator(
+                       'format',
+                       function(IFormField $formField) use ($regex, $languageItemPrefix) {
+                               if (!$regex->match($formField->getSaveValue())) {
+                                       $formField->addValidationError(
+                                               new FormFieldValidationError(
+                                                       'format',
+                                                       $languageItemPrefix . '.error.format'
+                                               )
+                                       );
+                               }
+                       }
+               );
+       }
+       
+       /**
+        * Disallow creating `FormFieldValidatorUtil` objects.
+        */
+       private function __construct() {
+               // does nothing
+       }
+}