--- /dev/null
+<?php
+
+namespace Drupal\Core\Form;
+
+use Drupal\Component\Utility\NestedArray;
+use Drupal\Core\Render\Element;
+
+/**
+ * Handles form errors.
+ */
+class FormErrorHandler implements FormErrorHandlerInterface {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function handleFormErrors(array &$form, FormStateInterface $form_state) {
+ // After validation check if there are errors.
+ if ($errors = $form_state->getErrors()) {
+ // Display error messages for each element.
+ $this->displayErrorMessages($form, $form_state);
+
+ // Loop through and assign each element its errors.
+ $this->setElementErrorsFromFormState($form, $form_state);
+ }
+
+ return $this;
+ }
+
+ /**
+ * Loops through and displays all form errors.
+ *
+ * @param array $form
+ * An associative array containing the structure of the form.
+ * @param \Drupal\Core\Form\FormStateInterface $form_state
+ * The current state of the form.
+ */
+ protected function displayErrorMessages(array $form, FormStateInterface $form_state) {
+ $errors = $form_state->getErrors();
+
+ // Loop through all form errors and set an error message.
+ foreach ($errors as $error) {
+ $this->drupalSetMessage($error, 'error');
+ }
+ }
+
+ /**
+ * Stores errors and a list of child element errors directly on each element.
+ *
+ * Grouping elements like containers, details, fieldgroups and fieldsets may
+ * need error info from their child elements to be able to accessibly show
+ * form error messages to a user. For example, a details element should be
+ * opened when child elements have errors.
+ *
+ * Grouping example:
+ * Assume you have a 'street' element somewhere in a form, which is displayed
+ * in a details element 'address'. It might be:
+ * @code
+ * $form['street'] = [
+ * '#type' => 'textfield',
+ * '#title' => $this->t('Street'),
+ * '#group' => 'address',
+ * '#required' => TRUE,
+ * ];
+ * $form['address'] = [
+ * '#type' => 'details',
+ * '#title' => $this->t('Address'),
+ * ];
+ * @endcode
+ *
+ * When submitting an empty street field, the generated error is available to
+ * the different render elements like so:
+ * @code
+ * // The street textfield element.
+ * $element = [
+ * '#errors' => {Drupal\Core\StringTranslation\TranslatableMarkup},
+ * '#children_errors' => [],
+ * ];
+ * // The address detail element.
+ * $element = [
+ * '#errors' => null,
+ * '#children_errors' => [
+ * 'street' => {Drupal\Core\StringTranslation\TranslatableMarkup}
+ * ],
+ * ];
+ * @endcode
+ *
+ * The list of child element errors of an element is an associative array. A
+ * child element error is keyed with the #array_parents value of the
+ * respective element. The key is formed by imploding this value with '][' as
+ * glue. For example, a value ['contact_info', 'name'] becomes
+ * 'contact_info][name'.
+ *
+ * @param array $form
+ * An associative array containing a reference to the complete structure of
+ * the form.
+ * @param \Drupal\Core\Form\FormStateInterface $form_state
+ * The current state of the form.
+ * @param array $elements
+ * An associative array containing the part of the form structure that will
+ * be processed while traversing up the tree. For recursion only; leave
+ * empty when calling this method.
+ */
+ protected function setElementErrorsFromFormState(array &$form, FormStateInterface $form_state, array &$elements = []) {
+ // At the start of traversing up the form tree set the to be processed
+ // elements to the complete form structure by reference so that we can
+ // modify the original form. When processing grouped elements a reference to
+ // the complete form is needed.
+ if (empty($elements)) {
+ $elements = &$form;
+ }
+
+ // Recurse through all element children.
+ foreach (Element::children($elements) as $key) {
+ if (!empty($elements[$key])) {
+ // Get the child by reference so that we can update the original form.
+ $child = &$elements[$key];
+
+ // Call self to traverse up the form tree. The current element's child
+ // contains the next elements to be processed.
+ $this->setElementErrorsFromFormState($form, $form_state, $child);
+
+ $children_errors = [];
+
+ // Inherit all recorded "children errors" of the direct child.
+ if (!empty($child['#children_errors'])) {
+ $children_errors = $child['#children_errors'];
+ }
+
+ // Additionally store the errors of the direct child itself, keyed by
+ // it's parent elements structure.
+ if (!empty($child['#errors'])) {
+ $child_parents = implode('][', $child['#array_parents']);
+ $children_errors[$child_parents] = $child['#errors'];
+ }
+
+ if (!empty($elements['#children_errors'])) {
+ $elements['#children_errors'] += $children_errors;
+ }
+ else {
+ $elements['#children_errors'] = $children_errors;
+ }
+
+ // If this direct child belongs to a group populate the grouping element
+ // with the children errors.
+ if (!empty($child['#group'])) {
+ $parents = explode('][', $child['#group']);
+ $group_element = NestedArray::getValue($form, $parents);
+ if (isset($group_element['#children_errors'])) {
+ $group_element['#children_errors'] = $group_element['#children_errors'] + $children_errors;
+ }
+ else {
+ $group_element['#children_errors'] = $children_errors;
+ }
+ NestedArray::setValue($form, $parents, $group_element);
+ }
+ }
+ }
+
+ // Store the errors for this element on the element directly.
+ $elements['#errors'] = $form_state->getError($elements);
+ }
+
+ /**
+ * Wraps drupal_set_message().
+ *
+ * @codeCoverageIgnore
+ */
+ protected function drupalSetMessage($message = NULL, $type = 'status', $repeat = FALSE) {
+ drupal_set_message($message, $type, $repeat);
+ }
+
+}
projects / yaffs-website / blobdiff