Add `IAttributeFormField`

diff --git a/wcfsetup/install/files/lib/system/form/builder/field/IAttributeFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/IAttributeFormField.class.php
new file mode 100644 (file)
index 0000000..dd40ad2
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/form/builder/field/IAttributeFormField.class.php
@@ -0,0 +1,62 @@
+<?php
+namespace wcf\system\form\builder\field;
+
+/**
+ * Represents a form fields that supports additional attributes for the actual form element.
+ *
+ * "additional" refers to existing attributes, like `class`, which can already be set via dedicated methods.
+ * The values of such attributes cannot be accessed or set with this API but only "additional" attributes for which
+ * no dedicated methods exist.
+ * If a class implementing this interface should add dedicated methods for certain attributes in the future, the methods
+ * of this interface should forwards calls to these dedicated methods.
+ *
+ * @author      Matthias Schmidt
+ * @copyright   2001-2020 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package     WoltLabSuite\Core\System\Form\Builder\Field
+ * @since       5.4
+ */
+interface IAttributeFormField extends IFormField {
+       /**
+        * Returns the value of the additional attribute of the actual field element with the given name.
+        *
+        * @throws      \InvalidArgumentException       if the given attribute is invalid or no such attribute exists
+        */
+       public function getFieldAttribute(string $name): self;
+       
+       /**
+        * Returns all additional attributes of the actual field element.
+        */
+       public function getFieldAttributes(): array;
+       
+       /**
+        * Adds the given additional attribute to the actual field element and returns this field.
+        *
+        * @throws      \InvalidArgumentException       if the given attribute is invalid
+        */
+       public function fieldAttribute(string $name, string $value = null): self;
+       
+       /**
+        * Returns `true` if an additional attribute of the actual field element with the given name exists and returns
+        * false` otherwise.
+        *
+        * @throws      \InvalidArgumentException       if the given attribute is invalid
+        */
+       public function hasFieldAttribute(string $name): bool;
+       
+       /**
+        * Removes the given additional attribute of the actual field element and returns this field.
+        *
+        * If the actual field element does not have the given attribute, this method silently ignores that fact.
+        *
+        * @throws      \InvalidArgumentException       if the given attribute is invalid
+        */
+       public function removeFieldAttribute(string $name): self;
+       
+       /**
+        * Checks if the given name is a valid additional attribute name.
+        *
+        * @throws      \InvalidArgumentException       if the given additional attribute name is invalid
+        */
+       public static function validateFieldAttribute(string $name);
+}