--- /dev/null
+<?php
+
+namespace Drupal\entity\Form;
+
+use Drupal\Core\Datetime\DateFormatterInterface;
+use Drupal\Core\Entity\EntityTypeBundleInfoInterface;
+use Drupal\Core\Entity\RevisionableInterface;
+use Drupal\Core\Form\ConfirmFormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Entity\RevisionLogInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpFoundation\Request;
+
+class RevisionRevertForm extends ConfirmFormBase {
+
+ /**
+ * The entity revision.
+ *
+ * @var \Drupal\Core\Entity\EntityInterface|\Drupal\Core\Entity\RevisionableInterface|\Drupal\Core\Entity\RevisionLogInterface
+ */
+ protected $revision;
+
+ /**
+ * The date formatter.
+ *
+ * @var \Drupal\Core\Datetime\DateFormatterInterface
+ */
+ protected $dateFormatter;
+
+ /**
+ * The entity bundle information.
+ *
+ * @var \Drupal\Core\Entity\EntityTypeBundleInfoInterface
+ */
+ protected $bundleInformation;
+
+ /**
+ * Creates a new RevisionRevertForm instance.
+ *
+ * @param \Drupal\Core\Datetime\DateFormatterInterface $date_formatter
+ * The date formatter.
+ * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $bundle_information
+ * The bundle information.
+ */
+ public function __construct(DateFormatterInterface $date_formatter, EntityTypeBundleInfoInterface $bundle_information) {
+ $this->dateFormatter = $date_formatter;
+ $this->bundleInformation = $bundle_information;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public static function create(ContainerInterface $container) {
+ return new static(
+ $container->get('date.formatter'),
+ $container->get('entity_type.bundle.info')
+ );
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getFormId() {
+ return 'entity_revision_revert_confirm';
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getQuestion() {
+ if ($this->revision instanceof RevisionLogInterface) {
+ return $this->t('Are you sure you want to revert to the revision from %revision-date?', ['%revision-date' => $this->dateFormatter->format($this->revision->getRevisionCreationTime())]);
+ }
+ return $this->t('Are you sure you want to revert the revision?');
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getCancelUrl() {
+ if ($this->revision->getEntityType()->hasLinkTemplate('version-history')) {
+ return $this->revision->toUrl('version-history');
+ }
+ return $this->revision->toUrl();
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getConfirmText() {
+ return t('Revert');
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getDescription() {
+ return '';
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function buildForm(array $form, FormStateInterface $form_state, $_entity_revision = NULL, Request $request = NULL) {
+ $this->revision = $_entity_revision;
+ $form = parent::buildForm($form, $form_state);
+
+ return $form;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function submitForm(array &$form, FormStateInterface $form_state) {
+ // The revision timestamp will be updated when the revision is saved. Keep
+ // the original one for the confirmation message.
+ $this->revision = $this->prepareRevision($this->revision);
+ if ($this->revision instanceof RevisionLogInterface) {
+ $original_revision_timestamp = $this->revision->getRevisionCreationTime();
+
+ $this->revision->setRevisionLogMessage($this->t('Copy of the revision from %date.', ['%date' => $this->dateFormatter->format($original_revision_timestamp)]));
+ $this->messenger()->addStatus(t('@type %title has been reverted to the revision from %revision-date.', [
+ '@type' => $this->getBundleLabel($this->revision),
+ '%title' => $this->revision->label(),
+ '%revision-date' => $this->dateFormatter->format($original_revision_timestamp),
+ ]));
+ }
+ else {
+ $this->messenger()->addStatus(t('@type %title has been reverted', [
+ '@type' => $this->getBundleLabel($this->revision),
+ '%title' => $this->revision->label(),
+ ]));
+ }
+
+ $this->revision->save();
+
+ $this->logger('content')->notice('@type: reverted %title revision %revision.', ['@type' => $this->revision->bundle(), '%title' => $this->revision->label(), '%revision' => $this->revision->getRevisionId()]);
+ $form_state->setRedirect(
+ "entity.{$this->revision->getEntityTypeId()}.version_history",
+ [$this->revision->getEntityTypeId() => $this->revision->id()]
+ );
+ }
+
+ /**
+ * Prepares a revision to be reverted.
+ *
+ * @param \Drupal\Core\Entity\RevisionableInterface $revision
+ * The revision to be reverted.
+ *
+ * @return \Drupal\Core\Entity\RevisionableInterface
+ * The prepared revision ready to be stored.
+ */
+ protected function prepareRevision(RevisionableInterface $revision) {
+ $revision->setNewRevision();
+ $revision->isDefaultRevision(TRUE);
+
+ return $revision;
+ }
+
+ /**
+ * Returns a bundle label.
+ *
+ * @param \Drupal\Core\Entity\RevisionableInterface $revision
+ * The entity revision.
+ *
+ * @return string
+ */
+ protected function getBundleLabel(RevisionableInterface $revision) {
+ /** @var \Drupal\Core\Entity\EntityInterface|\Drupal\Core\Entity\RevisionableInterface $revision */
+ $bundle_info = $this->bundleInformation->getBundleInfo($revision->getEntityTypeId());
+ return $bundle_info[$revision->bundle()]['label'];
+ }
+
+}