diff core/lib/Drupal/Core/Entity/ContentEntityBase.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/lib/Drupal/Core/Entity/ContentEntityBase.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,1364 @@
+<?php
+
+namespace Drupal\Core\Entity;
+
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\Entity\Plugin\DataType\EntityReference;
+use Drupal\Core\Field\BaseFieldDefinition;
+use Drupal\Core\Field\ChangedFieldItemList;
+use Drupal\Core\Language\Language;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\Core\TypedData\TranslationStatusInterface;
+use Drupal\Core\TypedData\TypedDataInterface;
+
+/**
+ * Implements Entity Field API specific enhancements to the Entity class.
+ *
+ * @ingroup entity_api
+ */
+abstract class ContentEntityBase extends Entity implements \IteratorAggregate, ContentEntityInterface, TranslationStatusInterface {
+
+  /**
+   * The plain data values of the contained fields.
+   *
+   * This always holds the original, unchanged values of the entity. The values
+   * are keyed by language code, whereas LanguageInterface::LANGCODE_DEFAULT
+   * is used for values in default language.
+   *
+   * @todo: Add methods for getting original fields and for determining
+   * changes.
+   * @todo: Provide a better way for defining default values.
+   *
+   * @var array
+   */
+  protected $values = [];
+
+  /**
+   * The array of fields, each being an instance of FieldItemListInterface.
+   *
+   * @var array
+   */
+  protected $fields = [];
+
+  /**
+   * Local cache for field definitions.
+   *
+   * @see ContentEntityBase::getFieldDefinitions()
+   *
+   * @var array
+   */
+  protected $fieldDefinitions;
+
+  /**
+   * Local cache for the available language objects.
+   *
+   * @var \Drupal\Core\Language\LanguageInterface[]
+   */
+  protected $languages;
+
+  /**
+   * The language entity key.
+   *
+   * @var string
+   */
+  protected $langcodeKey;
+
+  /**
+   * The default langcode entity key.
+   *
+   * @var string
+   */
+  protected $defaultLangcodeKey;
+
+  /**
+   * Language code identifying the entity active language.
+   *
+   * This is the language field accessors will use to determine which field
+   * values manipulate.
+   *
+   * @var string
+   */
+  protected $activeLangcode = LanguageInterface::LANGCODE_DEFAULT;
+
+  /**
+   * Local cache for the default language code.
+   *
+   * @var string
+   */
+  protected $defaultLangcode;
+
+  /**
+   * An array of entity translation metadata.
+   *
+   * An associative array keyed by translation language code. Every value is an
+   * array containing the translation status and the translation object, if it has
+   * already been instantiated.
+   *
+   * @var array
+   */
+  protected $translations = [];
+
+  /**
+   * A flag indicating whether a translation object is being initialized.
+   *
+   * @var bool
+   */
+  protected $translationInitialize = FALSE;
+
+  /**
+   * Boolean indicating whether a new revision should be created on save.
+   *
+   * @var bool
+   */
+  protected $newRevision = FALSE;
+
+  /**
+   * Indicates whether this is the default revision.
+   *
+   * @var bool
+   */
+  protected $isDefaultRevision = TRUE;
+
+  /**
+   * Holds untranslatable entity keys such as the ID, bundle, and revision ID.
+   *
+   * @var array
+   */
+  protected $entityKeys = [];
+
+  /**
+   * Holds translatable entity keys such as the label.
+   *
+   * @var array
+   */
+  protected $translatableEntityKeys = [];
+
+  /**
+   * Whether entity validation was performed.
+   *
+   * @var bool
+   */
+  protected $validated = FALSE;
+
+  /**
+   * Whether entity validation is required before saving the entity.
+   *
+   * @var bool
+   */
+  protected $validationRequired = FALSE;
+
+  /**
+   * The loaded revision ID before the new revision was set.
+   *
+   * @var int
+   */
+  protected $loadedRevisionId;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __construct(array $values, $entity_type, $bundle = FALSE, $translations = []) {
+    $this->entityTypeId = $entity_type;
+    $this->entityKeys['bundle'] = $bundle ? $bundle : $this->entityTypeId;
+    $this->langcodeKey = $this->getEntityType()->getKey('langcode');
+    $this->defaultLangcodeKey = $this->getEntityType()->getKey('default_langcode');
+
+    foreach ($values as $key => $value) {
+      // If the key matches an existing property set the value to the property
+      // to set properties like isDefaultRevision.
+      // @todo: Should this be converted somehow?
+      if (property_exists($this, $key) && isset($value[LanguageInterface::LANGCODE_DEFAULT])) {
+        $this->$key = $value[LanguageInterface::LANGCODE_DEFAULT];
+      }
+    }
+
+    $this->values = $values;
+    foreach ($this->getEntityType()->getKeys() as $key => $field_name) {
+      if (isset($this->values[$field_name])) {
+        if (is_array($this->values[$field_name])) {
+          // We store untranslatable fields into an entity key without using a
+          // langcode key.
+          if (!$this->getFieldDefinition($field_name)->isTranslatable()) {
+            if (isset($this->values[$field_name][LanguageInterface::LANGCODE_DEFAULT])) {
+              if (is_array($this->values[$field_name][LanguageInterface::LANGCODE_DEFAULT])) {
+                if (isset($this->values[$field_name][LanguageInterface::LANGCODE_DEFAULT][0]['value'])) {
+                  $this->entityKeys[$key] = $this->values[$field_name][LanguageInterface::LANGCODE_DEFAULT][0]['value'];
+                }
+              }
+              else {
+                $this->entityKeys[$key] = $this->values[$field_name][LanguageInterface::LANGCODE_DEFAULT];
+              }
+            }
+          }
+          else {
+            // We save translatable fields such as the publishing status of a node
+            // into an entity key array keyed by langcode as a performance
+            // optimization, so we don't have to go through TypedData when we
+            // need these values.
+            foreach ($this->values[$field_name] as $langcode => $field_value) {
+              if (is_array($this->values[$field_name][$langcode])) {
+                if (isset($this->values[$field_name][$langcode][0]['value'])) {
+                  $this->translatableEntityKeys[$key][$langcode] = $this->values[$field_name][$langcode][0]['value'];
+                }
+              }
+              else {
+                $this->translatableEntityKeys[$key][$langcode] = $this->values[$field_name][$langcode];
+              }
+            }
+          }
+        }
+      }
+    }
+
+    // Initialize translations. Ensure we have at least an entry for the default
+    // language.
+    // We determine if the entity is new by checking in the entity values for
+    // the presence of the id entity key, as the usage of ::isNew() is not
+    // possible in the constructor.
+    $data = isset($values[$this->getEntityType()->getKey('id')]) ? ['status' => static::TRANSLATION_EXISTING] : ['status' => static::TRANSLATION_CREATED];
+    $this->translations[LanguageInterface::LANGCODE_DEFAULT] = $data;
+    $this->setDefaultLangcode();
+    if ($translations) {
+      foreach ($translations as $langcode) {
+        if ($langcode != $this->defaultLangcode && $langcode != LanguageInterface::LANGCODE_DEFAULT) {
+          $this->translations[$langcode] = $data;
+        }
+      }
+    }
+    if ($this->getEntityType()->isRevisionable()) {
+      // Store the loaded revision ID the entity has been loaded with to
+      // keep it safe from changes.
+      $this->updateLoadedRevisionId();
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getLanguages() {
+    if (empty($this->languages)) {
+      $this->languages = $this->languageManager()->getLanguages(LanguageInterface::STATE_ALL);
+      // If the entity references a language that is not or no longer available,
+      // we return a mock language object to avoid disrupting the consuming
+      // code.
+      if (!isset($this->languages[$this->defaultLangcode])) {
+        $this->languages[$this->defaultLangcode] = new Language(['id' => $this->defaultLangcode]);
+      }
+    }
+    return $this->languages;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function postCreate(EntityStorageInterface $storage) {
+    $this->newRevision = TRUE;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setNewRevision($value = TRUE) {
+    if (!$this->getEntityType()->hasKey('revision')) {
+      throw new \LogicException("Entity type {$this->getEntityTypeId()} does not support revisions.");
+    }
+
+    if ($value && !$this->newRevision) {
+      // When saving a new revision, set any existing revision ID to NULL so as
+      // to ensure that a new revision will actually be created.
+      $this->set($this->getEntityType()->getKey('revision'), NULL);
+
+      // Make sure that the flag tracking which translations are affected by the
+      // current revision is reset.
+      foreach ($this->translations as $langcode => $data) {
+        // But skip removed translations.
+        if ($this->hasTranslation($langcode)) {
+          $this->getTranslation($langcode)->setRevisionTranslationAffected(NULL);
+        }
+      }
+    }
+
+    $this->newRevision = $value;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getLoadedRevisionId() {
+    return $this->loadedRevisionId;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function updateLoadedRevisionId() {
+    $this->loadedRevisionId = $this->getRevisionId() ?: $this->loadedRevisionId;
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function isNewRevision() {
+    return $this->newRevision || ($this->getEntityType()->hasKey('revision') && !$this->getRevisionId());
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function isDefaultRevision($new_value = NULL) {
+    $return = $this->isDefaultRevision;
+    if (isset($new_value)) {
+      $this->isDefaultRevision = (bool) $new_value;
+    }
+    // New entities should always ensure at least one default revision exists,
+    // creating an entity without a default revision is an invalid state.
+    return $this->isNew() || $return;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function isRevisionTranslationAffected() {
+    $field_name = $this->getEntityType()->getKey('revision_translation_affected');
+    return $this->hasField($field_name) ? $this->get($field_name)->value : TRUE;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setRevisionTranslationAffected($affected) {
+    $field_name = $this->getEntityType()->getKey('revision_translation_affected');
+    if ($this->hasField($field_name)) {
+      $this->set($field_name, $affected);
+    }
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function isDefaultTranslation() {
+    return $this->activeLangcode === LanguageInterface::LANGCODE_DEFAULT;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getRevisionId() {
+    return $this->getEntityKey('revision');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function isTranslatable() {
+    // Check that the bundle is translatable, the entity has a language defined
+    // and if we have more than one language on the site.
+    $bundles = $this->entityManager()->getBundleInfo($this->entityTypeId);
+    return !empty($bundles[$this->bundle()]['translatable']) && !$this->getUntranslated()->language()->isLocked() && $this->languageManager()->isMultilingual();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function preSave(EntityStorageInterface $storage) {
+    // An entity requiring validation should not be saved if it has not been
+    // actually validated.
+    if ($this->validationRequired && !$this->validated) {
+      // @todo Make this an assertion in https://www.drupal.org/node/2408013.
+      throw new \LogicException('Entity validation was skipped.');
+    }
+    else {
+      $this->validated = FALSE;
+    }
+
+    parent::preSave($storage);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function preSaveRevision(EntityStorageInterface $storage, \stdClass $record) {
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function postSave(EntityStorageInterface $storage, $update = TRUE) {
+    parent::postSave($storage, $update);
+
+    // Update the status of all saved translations.
+    $removed = [];
+    foreach ($this->translations as $langcode => &$data) {
+      if ($data['status'] == static::TRANSLATION_REMOVED) {
+        $removed[$langcode] = TRUE;
+      }
+      else {
+        $data['status'] = static::TRANSLATION_EXISTING;
+      }
+    }
+    $this->translations = array_diff_key($this->translations, $removed);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validate() {
+    $this->validated = TRUE;
+    $violations = $this->getTypedData()->validate();
+    return new EntityConstraintViolationList($this, iterator_to_array($violations));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function isValidationRequired() {
+    return (bool) $this->validationRequired;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setValidationRequired($required) {
+    $this->validationRequired = $required;
+    return $this;
+  }
+
+  /**
+   * Clear entity translation object cache to remove stale references.
+   */
+  protected function clearTranslationCache() {
+    foreach ($this->translations as &$translation) {
+      unset($translation['entity']);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __sleep() {
+    // Get the values of instantiated field objects, only serialize the values.
+    foreach ($this->fields as $name => $fields) {
+      foreach ($fields as $langcode => $field) {
+        $this->values[$name][$langcode] = $field->getValue();
+      }
+    }
+    $this->fields = [];
+    $this->fieldDefinitions = NULL;
+    $this->languages = NULL;
+    $this->clearTranslationCache();
+
+    return parent::__sleep();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function id() {
+    return $this->getEntityKey('id');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function bundle() {
+    return $this->getEntityKey('bundle');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function uuid() {
+    return $this->getEntityKey('uuid');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function hasField($field_name) {
+    return (bool) $this->getFieldDefinition($field_name);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function get($field_name) {
+    if (!isset($this->fields[$field_name][$this->activeLangcode])) {
+      return $this->getTranslatedField($field_name, $this->activeLangcode);
+    }
+    return $this->fields[$field_name][$this->activeLangcode];
+  }
+
+  /**
+   * Gets a translated field.
+   *
+   * @return \Drupal\Core\Field\FieldItemListInterface
+   */
+  protected function getTranslatedField($name, $langcode) {
+    if ($this->translations[$this->activeLangcode]['status'] == static::TRANSLATION_REMOVED) {
+      throw new \InvalidArgumentException("The entity object refers to a removed translation ({$this->activeLangcode}) and cannot be manipulated.");
+    }
+    // Populate $this->fields to speed-up further look-ups and to keep track of
+    // fields objects, possibly holding changes to field values.
+    if (!isset($this->fields[$name][$langcode])) {
+      $definition = $this->getFieldDefinition($name);
+      if (!$definition) {
+        throw new \InvalidArgumentException("Field $name is unknown.");
+      }
+      // Non-translatable fields are always stored with
+      // LanguageInterface::LANGCODE_DEFAULT as key.
+
+      $default = $langcode == LanguageInterface::LANGCODE_DEFAULT;
+      if (!$default && !$definition->isTranslatable()) {
+        if (!isset($this->fields[$name][LanguageInterface::LANGCODE_DEFAULT])) {
+          $this->fields[$name][LanguageInterface::LANGCODE_DEFAULT] = $this->getTranslatedField($name, LanguageInterface::LANGCODE_DEFAULT);
+        }
+        $this->fields[$name][$langcode] = &$this->fields[$name][LanguageInterface::LANGCODE_DEFAULT];
+      }
+      else {
+        $value = NULL;
+        if (isset($this->values[$name][$langcode])) {
+          $value = $this->values[$name][$langcode];
+        }
+        $field = \Drupal::service('plugin.manager.field.field_type')->createFieldItemList($this->getTranslation($langcode), $name, $value);
+        if ($default) {
+          // $this->defaultLangcode might not be set if we are initializing the
+          // default language code cache, in which case there is no valid
+          // langcode to assign.
+          $field_langcode = isset($this->defaultLangcode) ? $this->defaultLangcode : LanguageInterface::LANGCODE_NOT_SPECIFIED;
+        }
+        else {
+          $field_langcode = $langcode;
+        }
+        $field->setLangcode($field_langcode);
+        $this->fields[$name][$langcode] = $field;
+      }
+    }
+    return $this->fields[$name][$langcode];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function set($name, $value, $notify = TRUE) {
+    // Assign the value on the child and overrule notify such that we get
+    // notified to handle changes afterwards. We can ignore notify as there is
+    // no parent to notify anyway.
+    $this->get($name)->setValue($value, TRUE);
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFields($include_computed = TRUE) {
+    $fields = [];
+    foreach ($this->getFieldDefinitions() as $name => $definition) {
+      if ($include_computed || !$definition->isComputed()) {
+        $fields[$name] = $this->get($name);
+      }
+    }
+    return $fields;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getTranslatableFields($include_computed = TRUE) {
+    $fields = [];
+    foreach ($this->getFieldDefinitions() as $name => $definition) {
+      if (($include_computed || !$definition->isComputed()) && $definition->isTranslatable()) {
+        $fields[$name] = $this->get($name);
+      }
+    }
+    return $fields;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIterator() {
+    return new \ArrayIterator($this->getFields());
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFieldDefinition($name) {
+    if (!isset($this->fieldDefinitions)) {
+      $this->getFieldDefinitions();
+    }
+    if (isset($this->fieldDefinitions[$name])) {
+      return $this->fieldDefinitions[$name];
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFieldDefinitions() {
+    if (!isset($this->fieldDefinitions)) {
+      $this->fieldDefinitions = $this->entityManager()->getFieldDefinitions($this->entityTypeId, $this->bundle());
+    }
+    return $this->fieldDefinitions;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function toArray() {
+    $values = [];
+    foreach ($this->getFields() as $name => $property) {
+      $values[$name] = $property->getValue();
+    }
+    return $values;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function access($operation, AccountInterface $account = NULL, $return_as_object = FALSE) {
+    if ($operation == 'create') {
+      return $this->entityManager()
+        ->getAccessControlHandler($this->entityTypeId)
+        ->createAccess($this->bundle(), $account, [], $return_as_object);
+    }
+    return $this->entityManager()
+      ->getAccessControlHandler($this->entityTypeId)
+      ->access($this, $operation, $account, $return_as_object);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function language() {
+    $language = NULL;
+    if ($this->activeLangcode != LanguageInterface::LANGCODE_DEFAULT) {
+      if (!isset($this->languages[$this->activeLangcode])) {
+        $this->getLanguages();
+      }
+      $language = $this->languages[$this->activeLangcode];
+    }
+    else {
+      // @todo Avoid this check by getting the language from the language
+      //   manager directly in https://www.drupal.org/node/2303877.
+      if (!isset($this->languages[$this->defaultLangcode])) {
+        $this->getLanguages();
+      }
+      $language = $this->languages[$this->defaultLangcode];
+    }
+    return $language;
+  }
+
+  /**
+   * Populates the local cache for the default language code.
+   */
+  protected function setDefaultLangcode() {
+    // Get the language code if the property exists.
+    // Try to read the value directly from the list of entity keys which got
+    // initialized in __construct(). This avoids creating a field item object.
+    if (isset($this->translatableEntityKeys['langcode'][$this->activeLangcode])) {
+      $this->defaultLangcode = $this->translatableEntityKeys['langcode'][$this->activeLangcode];
+    }
+    elseif ($this->hasField($this->langcodeKey) && ($item = $this->get($this->langcodeKey)) && isset($item->language)) {
+      $this->defaultLangcode = $item->language->getId();
+      $this->translatableEntityKeys['langcode'][$this->activeLangcode] = $this->defaultLangcode;
+    }
+
+    if (empty($this->defaultLangcode)) {
+      // Make sure we return a proper language object, if the entity has a
+      // langcode field, default to the site's default language.
+      if ($this->hasField($this->langcodeKey)) {
+        $this->defaultLangcode = $this->languageManager()->getDefaultLanguage()->getId();
+      }
+      else {
+        $this->defaultLangcode = LanguageInterface::LANGCODE_NOT_SPECIFIED;
+      }
+    }
+
+    // This needs to be initialized manually as it is skipped when instantiating
+    // the language field object to avoid infinite recursion.
+    if (!empty($this->fields[$this->langcodeKey])) {
+      $this->fields[$this->langcodeKey][LanguageInterface::LANGCODE_DEFAULT]->setLangcode($this->defaultLangcode);
+    }
+  }
+
+  /**
+   * Updates language for already instantiated fields.
+   */
+  protected function updateFieldLangcodes($langcode) {
+    foreach ($this->fields as $name => $items) {
+      if (!empty($items[LanguageInterface::LANGCODE_DEFAULT])) {
+        $items[LanguageInterface::LANGCODE_DEFAULT]->setLangcode($langcode);
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function onChange($name) {
+    // Check if the changed name is the value of an entity key and if the value
+    // of that is currently cached, if so, reset it. Exclude the bundle from
+    // that check, as it ready only and must not change, unsetting it could
+    // lead to recursions.
+    if ($key = array_search($name, $this->getEntityType()->getKeys())) {
+      if ($key != 'bundle') {
+        if (isset($this->entityKeys[$key])) {
+          unset($this->entityKeys[$key]);
+        }
+        elseif (isset($this->translatableEntityKeys[$key][$this->activeLangcode])) {
+          unset($this->translatableEntityKeys[$key][$this->activeLangcode]);
+        }
+      }
+    }
+
+    switch ($name) {
+      case $this->langcodeKey:
+        if ($this->isDefaultTranslation()) {
+          // Update the default internal language cache.
+          $this->setDefaultLangcode();
+          if (isset($this->translations[$this->defaultLangcode])) {
+            $message = SafeMarkup::format('A translation already exists for the specified language (@langcode).', ['@langcode' => $this->defaultLangcode]);
+            throw new \InvalidArgumentException($message);
+          }
+          $this->updateFieldLangcodes($this->defaultLangcode);
+        }
+        else {
+          // @todo Allow the translation language to be changed. See
+          //   https://www.drupal.org/node/2443989.
+          $items = $this->get($this->langcodeKey);
+          if ($items->value != $this->activeLangcode) {
+            $items->setValue($this->activeLangcode, FALSE);
+            $message = SafeMarkup::format('The translation language cannot be changed (@langcode).', ['@langcode' => $this->activeLangcode]);
+            throw new \LogicException($message);
+          }
+        }
+        break;
+
+      case $this->defaultLangcodeKey:
+        // @todo Use a standard method to make the default_langcode field
+        //   read-only. See https://www.drupal.org/node/2443991.
+        if (isset($this->values[$this->defaultLangcodeKey]) && $this->get($this->defaultLangcodeKey)->value != $this->isDefaultTranslation()) {
+          $this->get($this->defaultLangcodeKey)->setValue($this->isDefaultTranslation(), FALSE);
+          $message = SafeMarkup::format('The default translation flag cannot be changed (@langcode).', ['@langcode' => $this->activeLangcode]);
+          throw new \LogicException($message);
+        }
+        break;
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getTranslation($langcode) {
+    // Ensure we always use the default language code when dealing with the
+    // original entity language.
+    if ($langcode != LanguageInterface::LANGCODE_DEFAULT && $langcode == $this->defaultLangcode) {
+      $langcode = LanguageInterface::LANGCODE_DEFAULT;
+    }
+
+    // Populate entity translation object cache so it will be available for all
+    // translation objects.
+    if ($langcode == $this->activeLangcode) {
+      $this->translations[$langcode]['entity'] = $this;
+    }
+
+    // If we already have a translation object for the specified language we can
+    // just return it.
+    if (isset($this->translations[$langcode]['entity'])) {
+      $translation = $this->translations[$langcode]['entity'];
+    }
+    // Otherwise if an existing translation language was specified we need to
+    // instantiate the related translation.
+    elseif (isset($this->translations[$langcode])) {
+      $translation = $this->initializeTranslation($langcode);
+      $this->translations[$langcode]['entity'] = $translation;
+    }
+
+    if (empty($translation)) {
+      throw new \InvalidArgumentException("Invalid translation language ($langcode) specified.");
+    }
+
+    return $translation;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getUntranslated() {
+    return $this->getTranslation(LanguageInterface::LANGCODE_DEFAULT);
+  }
+
+  /**
+   * Instantiates a translation object for an existing translation.
+   *
+   * The translated entity will be a clone of the current entity with the
+   * specified $langcode. All translations share the same field data structures
+   * to ensure that all of them deal with fresh data.
+   *
+   * @param string $langcode
+   *   The language code for the requested translation.
+   *
+   * @return \Drupal\Core\Entity\EntityInterface
+   *   The translation object. The content properties of the translation object
+   *   are stored as references to the main entity.
+   */
+  protected function initializeTranslation($langcode) {
+    // If the requested translation is valid, clone it with the current language
+    // as the active language. The $translationInitialize flag triggers a
+    // shallow (non-recursive) clone.
+    $this->translationInitialize = TRUE;
+    $translation = clone $this;
+    $this->translationInitialize = FALSE;
+
+    $translation->activeLangcode = $langcode;
+
+    // Ensure that changes to fields, values and translations are propagated
+    // to all the translation objects.
+    // @todo Consider converting these to ArrayObject.
+    $translation->values = &$this->values;
+    $translation->fields = &$this->fields;
+    $translation->translations = &$this->translations;
+    $translation->enforceIsNew = &$this->enforceIsNew;
+    $translation->newRevision = &$this->newRevision;
+    $translation->entityKeys = &$this->entityKeys;
+    $translation->translatableEntityKeys = &$this->translatableEntityKeys;
+    $translation->translationInitialize = FALSE;
+    $translation->typedData = NULL;
+    $translation->loadedRevisionId = &$this->loadedRevisionId;
+    $translation->isDefaultRevision = &$this->isDefaultRevision;
+
+    return $translation;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function hasTranslation($langcode) {
+    if ($langcode == $this->defaultLangcode) {
+      $langcode = LanguageInterface::LANGCODE_DEFAULT;
+    }
+    return !empty($this->translations[$langcode]['status']);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function isNewTranslation() {
+    return $this->translations[$this->activeLangcode]['status'] == static::TRANSLATION_CREATED;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function addTranslation($langcode, array $values = []) {
+    // Make sure we do not attempt to create a translation if an invalid
+    // language is specified or the entity cannot be translated.
+    $this->getLanguages();
+    if (!isset($this->languages[$langcode]) || $this->hasTranslation($langcode) || $this->languages[$langcode]->isLocked()) {
+      throw new \InvalidArgumentException("Invalid translation language ($langcode) specified.");
+    }
+    if ($this->languages[$this->defaultLangcode]->isLocked()) {
+      throw new \InvalidArgumentException("The entity cannot be translated since it is language neutral ({$this->defaultLangcode}).");
+    }
+
+    // Initialize the translation object.
+    /** @var \Drupal\Core\Entity\ContentEntityStorageInterface $storage */
+    $storage = $this->entityManager()->getStorage($this->getEntityTypeId());
+    $this->translations[$langcode]['status'] = !isset($this->translations[$langcode]['status_existed']) ? static::TRANSLATION_CREATED : static::TRANSLATION_EXISTING;
+    return $storage->createTranslation($this, $langcode, $values);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function removeTranslation($langcode) {
+    if (isset($this->translations[$langcode]) && $langcode != LanguageInterface::LANGCODE_DEFAULT && $langcode != $this->defaultLangcode) {
+      foreach ($this->getFieldDefinitions() as $name => $definition) {
+        if ($definition->isTranslatable()) {
+          unset($this->values[$name][$langcode]);
+          unset($this->fields[$name][$langcode]);
+        }
+      }
+      // If removing a translation which has not been saved yet, then we have
+      // to remove it completely so that ::getTranslationStatus returns the
+      // proper status.
+      if ($this->translations[$langcode]['status'] == static::TRANSLATION_CREATED) {
+        unset($this->translations[$langcode]);
+      }
+      else {
+        if ($this->translations[$langcode]['status'] == static::TRANSLATION_EXISTING) {
+          $this->translations[$langcode]['status_existed'] = TRUE;
+        }
+        $this->translations[$langcode]['status'] = static::TRANSLATION_REMOVED;
+      }
+    }
+    else {
+      throw new \InvalidArgumentException("The specified translation ($langcode) cannot be removed.");
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getTranslationStatus($langcode) {
+    if ($langcode == $this->defaultLangcode) {
+      $langcode = LanguageInterface::LANGCODE_DEFAULT;
+    }
+    return isset($this->translations[$langcode]) ? $this->translations[$langcode]['status'] : NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getTranslationLanguages($include_default = TRUE) {
+    $translations = array_filter($this->translations, function ($translation) {
+      return $translation['status'];
+    });
+    unset($translations[LanguageInterface::LANGCODE_DEFAULT]);
+
+    if ($include_default) {
+      $translations[$this->defaultLangcode] = TRUE;
+    }
+
+    // Now load language objects based upon translation langcodes.
+    return array_intersect_key($this->getLanguages(), $translations);
+  }
+
+  /**
+   * Updates the original values with the interim changes.
+   */
+  public function updateOriginalValues() {
+    if (!$this->fields) {
+      return;
+    }
+    foreach ($this->getFieldDefinitions() as $name => $definition) {
+      if (!$definition->isComputed() && !empty($this->fields[$name])) {
+        foreach ($this->fields[$name] as $langcode => $item) {
+          $item->filterEmptyItems();
+          $this->values[$name][$langcode] = $item->getValue();
+        }
+      }
+    }
+  }
+
+  /**
+   * Implements the magic method for getting object properties.
+   *
+   * @todo: A lot of code still uses non-fields (e.g. $entity->content in view
+   *   builders) by reference. Clean that up.
+   */
+  public function &__get($name) {
+    // If this is an entity field, handle it accordingly. We first check whether
+    // a field object has been already created. If not, we create one.
+    if (isset($this->fields[$name][$this->activeLangcode])) {
+      return $this->fields[$name][$this->activeLangcode];
+    }
+    // Inline getFieldDefinition() to speed things up.
+    if (!isset($this->fieldDefinitions)) {
+      $this->getFieldDefinitions();
+    }
+    if (isset($this->fieldDefinitions[$name])) {
+      $return = $this->getTranslatedField($name, $this->activeLangcode);
+      return $return;
+    }
+    // Else directly read/write plain values. That way, non-field entity
+    // properties can always be accessed directly.
+    if (!isset($this->values[$name])) {
+      $this->values[$name] = NULL;
+    }
+    return $this->values[$name];
+  }
+
+  /**
+   * Implements the magic method for setting object properties.
+   *
+   * Uses default language always.
+   */
+  public function __set($name, $value) {
+    // Inline getFieldDefinition() to speed things up.
+    if (!isset($this->fieldDefinitions)) {
+      $this->getFieldDefinitions();
+    }
+    // Handle Field API fields.
+    if (isset($this->fieldDefinitions[$name])) {
+      // Support setting values via property objects.
+      if ($value instanceof TypedDataInterface) {
+        $value = $value->getValue();
+      }
+      // If a FieldItemList object already exists, set its value.
+      if (isset($this->fields[$name][$this->activeLangcode])) {
+        $this->fields[$name][$this->activeLangcode]->setValue($value);
+      }
+      // If not, create one.
+      else {
+        $this->getTranslatedField($name, $this->activeLangcode)->setValue($value);
+      }
+    }
+    // The translations array is unset when cloning the entity object, we just
+    // need to restore it.
+    elseif ($name == 'translations') {
+      $this->translations = $value;
+    }
+    // Directly write non-field values.
+    else {
+      $this->values[$name] = $value;
+    }
+  }
+
+  /**
+   * Implements the magic method for isset().
+   */
+  public function __isset($name) {
+    // "Official" Field API fields are always set. For non-field properties,
+    // check the internal values.
+    return $this->hasField($name) ? TRUE : isset($this->values[$name]);
+  }
+
+  /**
+   * Implements the magic method for unset().
+   */
+  public function __unset($name) {
+    // Unsetting a field means emptying it.
+    if ($this->hasField($name)) {
+      $this->get($name)->setValue([]);
+    }
+    // For non-field properties, unset the internal value.
+    else {
+      unset($this->values[$name]);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function createDuplicate() {
+    if ($this->translations[$this->activeLangcode]['status'] == static::TRANSLATION_REMOVED) {
+      throw new \InvalidArgumentException("The entity object refers to a removed translation ({$this->activeLangcode}) and cannot be manipulated.");
+    }
+
+    $duplicate = clone $this;
+    $entity_type = $this->getEntityType();
+    $duplicate->{$entity_type->getKey('id')}->value = NULL;
+    $duplicate->enforceIsNew();
+
+    // Check if the entity type supports UUIDs and generate a new one if so.
+    if ($entity_type->hasKey('uuid')) {
+      $duplicate->{$entity_type->getKey('uuid')}->value = $this->uuidGenerator()->generate();
+    }
+
+    // Check whether the entity type supports revisions and initialize it if so.
+    if ($entity_type->isRevisionable()) {
+      $duplicate->{$entity_type->getKey('revision')}->value = NULL;
+      $duplicate->loadedRevisionId = NULL;
+    }
+
+    return $duplicate;
+  }
+
+  /**
+   * Magic method: Implements a deep clone.
+   */
+  public function __clone() {
+    // Avoid deep-cloning when we are initializing a translation object, since
+    // it will represent the same entity, only with a different active language.
+    if ($this->translationInitialize) {
+      return;
+    }
+
+    // The translation is a different object, and needs its own TypedData
+    // adapter object.
+    $this->typedData = NULL;
+    $definitions = $this->getFieldDefinitions();
+
+    // The translation cache has to be cleared before cloning the fields
+    // below so that the call to getTranslation() does not re-use the
+    // translation objects of the old entity but instead creates new
+    // translation objects from the newly cloned entity. Otherwise the newly
+    // cloned field item lists would hold references to the old translation
+    // objects in their $parent property after the call to setContext().
+    $this->clearTranslationCache();
+
+    // Because the new translation objects that are created below are
+    // themselves created by *cloning* the newly cloned entity we need to
+    // make sure that the references to property values are properly cloned
+    // before cloning the fields. Otherwise calling
+    // $items->getEntity()->isNew(), for example, would return the
+    // $enforceIsNew value of the old entity.
+
+    // Ensure the translations array is actually cloned by overwriting the
+    // original reference with one pointing to a copy of the array.
+    $translations = $this->translations;
+    $this->translations = &$translations;
+
+    // Ensure that the following properties are actually cloned by
+    // overwriting the original references with ones pointing to copies of
+    // them: enforceIsNew, newRevision, loadedRevisionId, fields, entityKeys,
+    // translatableEntityKeys, values and isDefaultRevision.
+    $enforce_is_new = $this->enforceIsNew;
+    $this->enforceIsNew = &$enforce_is_new;
+
+    $new_revision = $this->newRevision;
+    $this->newRevision = &$new_revision;
+
+    $original_revision_id = $this->loadedRevisionId;
+    $this->loadedRevisionId = &$original_revision_id;
+
+    $fields = $this->fields;
+    $this->fields = &$fields;
+
+    $entity_keys = $this->entityKeys;
+    $this->entityKeys = &$entity_keys;
+
+    $translatable_entity_keys = $this->translatableEntityKeys;
+    $this->translatableEntityKeys = &$translatable_entity_keys;
+
+    $values = $this->values;
+    $this->values = &$values;
+
+    $default_revision = $this->isDefaultRevision;
+    $this->isDefaultRevision = &$default_revision;
+
+    foreach ($this->fields as $name => $fields_by_langcode) {
+      $this->fields[$name] = [];
+      // Untranslatable fields may have multiple references for the same field
+      // object keyed by language. To avoid creating different field objects
+      // we retain just the original value, as references will be recreated
+      // later as needed.
+      if (!$definitions[$name]->isTranslatable() && count($fields_by_langcode) > 1) {
+        $fields_by_langcode = array_intersect_key($fields_by_langcode, [LanguageInterface::LANGCODE_DEFAULT => TRUE]);
+      }
+      foreach ($fields_by_langcode as $langcode => $items) {
+        $this->fields[$name][$langcode] = clone $items;
+        $this->fields[$name][$langcode]->setContext($name, $this->getTranslation($langcode)->getTypedData());
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function label() {
+    $label = NULL;
+    $entity_type = $this->getEntityType();
+    if (($label_callback = $entity_type->getLabelCallback()) && is_callable($label_callback)) {
+      $label = call_user_func($label_callback, $this);
+    }
+    elseif (($label_key = $entity_type->getKey('label'))) {
+      $label = $this->getEntityKey('label');
+    }
+    return $label;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function referencedEntities() {
+    $referenced_entities = [];
+
+    // Gather a list of referenced entities.
+    foreach ($this->getFields() as $field_items) {
+      foreach ($field_items as $field_item) {
+        // Loop over all properties of a field item.
+        foreach ($field_item->getProperties(TRUE) as $property) {
+          if ($property instanceof EntityReference && $entity = $property->getValue()) {
+            $referenced_entities[] = $entity;
+          }
+        }
+      }
+    }
+
+    return $referenced_entities;
+  }
+
+  /**
+   * Gets the value of the given entity key, if defined.
+   *
+   * @param string $key
+   *   Name of the entity key, for example id, revision or bundle.
+   *
+   * @return mixed
+   *   The value of the entity key, NULL if not defined.
+   */
+  protected function getEntityKey($key) {
+    // If the value is known already, return it.
+    if (isset($this->entityKeys[$key])) {
+      return $this->entityKeys[$key];
+    }
+    if (isset($this->translatableEntityKeys[$key][$this->activeLangcode])) {
+      return $this->translatableEntityKeys[$key][$this->activeLangcode];
+    }
+
+    // Otherwise fetch the value by creating a field object.
+    $value = NULL;
+    if ($this->getEntityType()->hasKey($key)) {
+      $field_name = $this->getEntityType()->getKey($key);
+      $definition = $this->getFieldDefinition($field_name);
+      $property = $definition->getFieldStorageDefinition()->getMainPropertyName();
+      $value = $this->get($field_name)->$property;
+
+      // Put it in the right array, depending on whether it is translatable.
+      if ($definition->isTranslatable()) {
+        $this->translatableEntityKeys[$key][$this->activeLangcode] = $value;
+      }
+      else {
+        $this->entityKeys[$key] = $value;
+      }
+    }
+    else {
+      $this->entityKeys[$key] = $value;
+    }
+    return $value;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
+    $fields = [];
+    if ($entity_type->hasKey('id')) {
+      $fields[$entity_type->getKey('id')] = BaseFieldDefinition::create('integer')
+        ->setLabel(new TranslatableMarkup('ID'))
+        ->setReadOnly(TRUE)
+        ->setSetting('unsigned', TRUE);
+    }
+    if ($entity_type->hasKey('uuid')) {
+      $fields[$entity_type->getKey('uuid')] = BaseFieldDefinition::create('uuid')
+        ->setLabel(new TranslatableMarkup('UUID'))
+        ->setReadOnly(TRUE);
+    }
+    if ($entity_type->hasKey('revision')) {
+      $fields[$entity_type->getKey('revision')] = BaseFieldDefinition::create('integer')
+        ->setLabel(new TranslatableMarkup('Revision ID'))
+        ->setReadOnly(TRUE)
+        ->setSetting('unsigned', TRUE);
+    }
+    if ($entity_type->hasKey('langcode')) {
+      $fields[$entity_type->getKey('langcode')] = BaseFieldDefinition::create('language')
+        ->setLabel(new TranslatableMarkup('Language'))
+        ->setDisplayOptions('view', [
+          'region' => 'hidden',
+        ])
+        ->setDisplayOptions('form', [
+          'type' => 'language_select',
+          'weight' => 2,
+        ]);
+      if ($entity_type->isRevisionable()) {
+        $fields[$entity_type->getKey('langcode')]->setRevisionable(TRUE);
+      }
+      if ($entity_type->isTranslatable()) {
+        $fields[$entity_type->getKey('langcode')]->setTranslatable(TRUE);
+      }
+    }
+    if ($entity_type->hasKey('bundle')) {
+      if ($bundle_entity_type_id = $entity_type->getBundleEntityType()) {
+        $fields[$entity_type->getKey('bundle')] = BaseFieldDefinition::create('entity_reference')
+          ->setLabel($entity_type->getBundleLabel())
+          ->setSetting('target_type', $bundle_entity_type_id)
+          ->setRequired(TRUE)
+          ->setReadOnly(TRUE);
+      }
+      else {
+        $fields[$entity_type->getKey('bundle')] = BaseFieldDefinition::create('string')
+          ->setLabel($entity_type->getBundleLabel())
+          ->setRequired(TRUE)
+          ->setReadOnly(TRUE);
+      }
+    }
+
+    return $fields;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function bundleFieldDefinitions(EntityTypeInterface $entity_type, $bundle, array $base_field_definitions) {
+    return [];
+  }
+
+  /**
+   * Returns an array of field names to skip in ::hasTranslationChanges.
+   *
+   * @return array
+   *   An array of field names.
+   */
+  protected function getFieldsToSkipFromTranslationChangesCheck() {
+    /** @var \Drupal\Core\Entity\ContentEntityTypeInterface $entity_type */
+    $entity_type = $this->getEntityType();
+    // A list of known revision metadata fields which should be skipped from
+    // the comparision.
+    $fields = [
+      $entity_type->getKey('revision'),
+      'revision_translation_affected',
+    ];
+    $fields = array_merge($fields, array_values($entity_type->getRevisionMetadataKeys()));
+
+    return $fields;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function hasTranslationChanges() {
+    if ($this->isNew()) {
+      return TRUE;
+    }
+
+    // $this->original only exists during save. See
+    // \Drupal\Core\Entity\EntityStorageBase::save(). If it exists we re-use it
+    // here for performance reasons.
+    /** @var \Drupal\Core\Entity\ContentEntityBase $original */
+    $original = $this->original ? $this->original : NULL;
+
+    if (!$original) {
+      $id = $this->getOriginalId() !== NULL ? $this->getOriginalId() : $this->id();
+      $original = $this->entityManager()->getStorage($this->getEntityTypeId())->loadUnchanged($id);
+    }
+
+    // If the current translation has just been added, we have a change.
+    $translated = count($this->translations) > 1;
+    if ($translated && !$original->hasTranslation($this->activeLangcode)) {
+      return TRUE;
+    }
+
+    // Compare field item current values with the original ones to determine
+    // whether we have changes. If a field is not translatable and the entity is
+    // translated we skip it because, depending on the use case, it would make
+    // sense to mark all translations as changed or none of them. We skip also
+    // computed fields as comparing them with their original values might not be
+    // possible or be meaningless.
+    /** @var \Drupal\Core\Entity\ContentEntityBase $translation */
+    $translation = $original->getTranslation($this->activeLangcode);
+
+    // The list of fields to skip from the comparision.
+    $skip_fields = $this->getFieldsToSkipFromTranslationChangesCheck();
+
+    foreach ($this->getFieldDefinitions() as $field_name => $definition) {
+      // @todo Avoid special-casing the following fields. See
+      //    https://www.drupal.org/node/2329253.
+      if (in_array($field_name, $skip_fields, TRUE)) {
+        continue;
+      }
+      $field = $this->get($field_name);
+      // When saving entities in the user interface, the changed timestamp is
+      // automatically incremented by ContentEntityForm::submitForm() even if
+      // nothing was actually changed. Thus, the changed time needs to be
+      // ignored when determining whether there are any actual changes in the
+      // entity.
+      if (!($field instanceof ChangedFieldItemList) && !$definition->isComputed()) {
+        $items = $field->filterEmptyItems();
+        $original_items = $translation->get($field_name)->filterEmptyItems();
+        if (!$items->equals($original_items)) {
+          return TRUE;
+        }
+      }
+    }
+
+    return FALSE;
+  }
+
+}