drupal/core/modules/content_moderation/content_moderation.module

<?php

/**
 * @file
 * Contains content_moderation.module.
 */

use Drupal\content_moderation\EntityOperations;
use Drupal\content_moderation\EntityTypeInfo;
use Drupal\content_moderation\ContentPreprocess;
use Drupal\content_moderation\Plugin\Action\ModerationOptOutPublish;
use Drupal\content_moderation\Plugin\Action\ModerationOptOutUnpublish;
use Drupal\Core\Access\AccessResult;
use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\EntityPublishedInterface;
use Drupal\Core\Entity\EntityTypeInterface;
use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Url;
use Drupal\workflows\WorkflowInterface;
use Drupal\Core\Action\Plugin\Action\PublishAction;
use Drupal\Core\Action\Plugin\Action\UnpublishAction;
use Drupal\workflows\Entity\Workflow;
use Drupal\views\Entity\View;

/**
 * Implements hook_help().
 */
function content_moderation_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the content_moderation module.
    case 'help.page.content_moderation':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Content Moderation module allows you to expand on Drupal\'s "unpublished" and "published" states for content. It allows you to have a published version that is live, but have a separate working copy that is undergoing review before it is published. This is achieved by using <a href=":workflows">Workflows</a> to apply different states and transitions to entities as needed. For more information, see the <a href=":content_moderation">online documentation for the Content Moderation module</a>.', [':content_moderation' => 'https://www.drupal.org/documentation/modules/content_moderation', ':workflows' => Url::fromRoute('help.page', ['name' => 'workflows'])->toString()]) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Applying workflows') . '</dt>';
      $output .= '<dd>' . t('Content Moderation allows you to apply <a href=":workflows">Workflows</a> to content, custom blocks, and other <a href=":field_help" title="Field module help, with background on content entities">content entities</a>, to provide more fine-grained publishing options. For example, a Basic page might have states such as Draft and Published, with allowed transitions such as Draft to Published (making the current revision "live"), and Published to Draft (making a new draft revision of published content).', [':workflows' => Url::fromRoute('help.page', ['name' => 'workflows'])->toString(), ':field_help' => Url::fromRoute('help.page', ['name' => 'field'])->toString()]) . '</dd>';
      if (\Drupal::moduleHandler()->moduleExists('views')) {
        $moderated_content_view = View::load('moderated_content');
        if (isset($moderated_content_view) && $moderated_content_view->status() === TRUE) {
          $output .= '<dt>' . t('Moderating content') . '</dt>';
          $output .= '<dd>' . t('You can view a list of content awaiting moderation on the <a href=":moderated">moderated content page</a>. This will show any content in an unpublished state, such as Draft or Archived, to help surface content that requires more work from content editors.', [':moderated' => Url::fromRoute('view.moderated_content.moderated_content')->toString()]) . '</dd>';
        }
      }
      $output .= '<dt>' . t('Configure Content Moderation permissions') . '</dt>';
      $output .= '<dd>' . t('Each transition is exposed as a permission. If a user has the permission for a transition, they can use the transition to change the state of the content item, from Draft to Published.') . '</dd>';
      $output .= '</dl>';
      return $output;
  }
}

/**
 * Implements hook_entity_base_field_info().
 */
function content_moderation_entity_base_field_info(EntityTypeInterface $entity_type) {
  return \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityTypeInfo::class)
    ->entityBaseFieldInfo($entity_type);
}

/**
 * Implements hook_entity_type_alter().
 */
function content_moderation_entity_type_alter(array &$entity_types) {
  \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityTypeInfo::class)
    ->entityTypeAlter($entity_types);
}

/**
 * Implements hook_entity_presave().
 */
function content_moderation_entity_presave(EntityInterface $entity) {
  return \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityOperations::class)
    ->entityPresave($entity);
}

/**
 * Implements hook_entity_insert().
 */
function content_moderation_entity_insert(EntityInterface $entity) {
  return \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityOperations::class)
    ->entityInsert($entity);
}

/**
 * Implements hook_entity_update().
 */
function content_moderation_entity_update(EntityInterface $entity) {
  return \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityOperations::class)
    ->entityUpdate($entity);
}

/**
 * Implements hook_entity_delete().
 */
function content_moderation_entity_delete(EntityInterface $entity) {
  return \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityOperations::class)
    ->entityDelete($entity);
}

/**
 * Implements hook_entity_revision_delete().
 */
function content_moderation_entity_revision_delete(EntityInterface $entity) {
  return \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityOperations::class)
    ->entityRevisionDelete($entity);
}

/**
 * Implements hook_entity_translation_delete().
 */
function content_moderation_entity_translation_delete(EntityInterface $translation) {
  return \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityOperations::class)
    ->entityTranslationDelete($translation);
}

/**
 * Implements hook_entity_prepare_form().
 */
function content_moderation_entity_prepare_form(EntityInterface $entity, $operation, FormStateInterface $form_state) {
  \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityTypeInfo::class)
    ->entityPrepareForm($entity, $operation, $form_state);
}

/**
 * Implements hook_form_alter().
 */
function content_moderation_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityTypeInfo::class)
    ->formAlter($form, $form_state, $form_id);
}

/**
 * Implements hook_preprocess_HOOK().
 */
function content_moderation_preprocess_node(&$variables) {
  \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(ContentPreprocess::class)
    ->preprocessNode($variables);
}

/**
 * Implements hook_entity_extra_field_info().
 */
function content_moderation_entity_extra_field_info() {
  return \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityTypeInfo::class)
    ->entityExtraFieldInfo();
}

/**
 * Implements hook_entity_view().
 */
function content_moderation_entity_view(array &$build, EntityInterface $entity, EntityViewDisplayInterface $display, $view_mode) {
  \Drupal::service('class_resolver')
    ->getInstanceFromDefinition(EntityOperations::class)
    ->entityView($build, $entity, $display, $view_mode);
}

/**
 * Implements hook_entity_access().
 *
 * Entities should be viewable if unpublished and the user has the appropriate
 * permission. This permission is therefore effectively mandatory for any user
 * that wants to moderate things.
 */
function content_moderation_entity_access(EntityInterface $entity, $operation, AccountInterface $account) {
  /** @var \Drupal\content_moderation\ModerationInformationInterface $moderation_info */
  $moderation_info = Drupal::service('content_moderation.moderation_information');

  $access_result = NULL;
  if ($operation === 'view') {
    $access_result = (($entity instanceof EntityPublishedInterface) && !$entity->isPublished())
      ? AccessResult::allowedIfHasPermission($account, 'view any unpublished content')
      : AccessResult::neutral();

    $access_result->addCacheableDependency($entity);
  }
  elseif ($operation === 'update' && $moderation_info->isModeratedEntity($entity) && $entity->moderation_state) {
    /** @var \Drupal\content_moderation\StateTransitionValidation $transition_validation */
    $transition_validation = \Drupal::service('content_moderation.state_transition_validation');

    $valid_transition_targets = $transition_validation->getValidTransitions($entity, $account);
    $access_result = $valid_transition_targets ? AccessResult::neutral() : AccessResult::forbidden('No valid transitions exist for given account.');

    $access_result->addCacheableDependency($entity);
    $access_result->addCacheableDependency($account);
    $workflow = $moderation_info->getWorkflowForEntity($entity);
    $access_result->addCacheableDependency($workflow);
    foreach ($valid_transition_targets as $valid_transition_target) {
      $access_result->addCacheableDependency($valid_transition_target);
    }
  }

  return $access_result;
}

/**
 * Implements hook_entity_field_access().
 */
function content_moderation_entity_field_access($operation, FieldDefinitionInterface $field_definition, AccountInterface $account, FieldItemListInterface $items = NULL) {
  if ($items && $operation === 'edit') {
    /** @var \Drupal\content_moderation\ModerationInformationInterface $moderation_info */
    $moderation_info = Drupal::service('content_moderation.moderation_information');

    $entity_type = \Drupal::entityTypeManager()->getDefinition($field_definition->getTargetEntityTypeId());

    $entity = $items->getEntity();

    // Deny edit access to the published field if the entity is being moderated.
    if ($entity_type->hasKey('published') && $moderation_info->isModeratedEntity($entity) && $entity->moderation_state && $field_definition->getName() == $entity_type->getKey('published')) {
      return AccessResult::forbidden('Cannot edit the published field of moderated entities.');
    }
  }

  return AccessResult::neutral();
}

/**
 * Implements hook_theme().
 */
function content_moderation_theme() {
  return ['entity_moderation_form' => ['render element' => 'form']];
}

/**
 * Implements hook_action_info_alter().
 */
function content_moderation_action_info_alter(&$definitions) {

  // The publish/unpublish actions are not valid on moderated entities. So swap
  // their implementations out for alternates that will become a no-op on a
  // moderated entity. If another module has already swapped out those classes,
  // though, we'll be polite and do nothing.
  foreach ($definitions as &$definition) {
    if ($definition['id'] === 'entity:publish_action' && $definition['class'] == PublishAction::class) {
      $definition['class'] = ModerationOptOutPublish::class;
    }
    if ($definition['id'] === 'entity:unpublish_action' && $definition['class'] == UnpublishAction::class) {
      $definition['class'] = ModerationOptOutUnpublish::class;
    }
  }
}

/**
 * Implements hook_entity_bundle_info_alter().
 */
function content_moderation_entity_bundle_info_alter(&$bundles) {
  $translatable = FALSE;
  /** @var \Drupal\workflows\WorkflowInterface $workflow */
  foreach (Workflow::loadMultipleByType('content_moderation') as $workflow) {
    /** @var \Drupal\content_moderation\Plugin\WorkflowType\ContentModeration $plugin */
    $plugin = $workflow->getTypePlugin();
    foreach ($plugin->getEntityTypes() as $entity_type_id) {
      foreach ($plugin->getBundlesForEntityType($entity_type_id) as $bundle_id) {
        if (isset($bundles[$entity_type_id][$bundle_id])) {
          $bundles[$entity_type_id][$bundle_id]['workflow'] = $workflow->id();
          // If we have even one moderation-enabled translatable bundle, we need
          // to make the moderation state bundle translatable as well, to enable
          // the revision translation merge logic also for content moderation
          // state revisions.
          if (!empty($bundles[$entity_type_id][$bundle_id]['translatable'])) {
            $translatable = TRUE;
          }
        }
      }
    }
  }
  $bundles['content_moderation_state']['content_moderation_state']['translatable'] = $translatable;
}

/**
 * Implements hook_entity_bundle_delete().
 */
function content_moderation_entity_bundle_delete($entity_type_id, $bundle_id) {
  // Remove non-configuration based bundles from content moderation based
  // workflows when they are removed.
  foreach (Workflow::loadMultipleByType('content_moderation') as $workflow) {
    if ($workflow->getTypePlugin()->appliesToEntityTypeAndBundle($entity_type_id, $bundle_id)) {
      $workflow->getTypePlugin()->removeEntityTypeAndBundle($entity_type_id, $bundle_id);
      $workflow->save();
    }
  }
}

/**
 * Implements hook_ENTITY_TYPE_insert().
 */
function content_moderation_workflow_insert(WorkflowInterface $entity) {
  // Clear bundle cache so workflow gets added or removed from the bundle
  // information.
  \Drupal::service('entity_type.bundle.info')->clearCachedBundles();
  // Clear field cache so extra field is added or removed.
  \Drupal::service('entity_field.manager')->clearCachedFieldDefinitions();
}

/**
 * Implements hook_ENTITY_TYPE_update().
 */
function content_moderation_workflow_update(WorkflowInterface $entity) {
  // Clear bundle cache so workflow gets added or removed from the bundle
  // information.
  \Drupal::service('entity_type.bundle.info')->clearCachedBundles();
  // Clear field cache so extra field is added or removed.
  \Drupal::service('entity_field.manager')->clearCachedFieldDefinitions();
}