Club Drupal

<?php

/**

 * @file

 * Provides wrappers allowing easy usage of the entity metadata.

 */

/**

 * A common base class for all wrappers.

 */

abstract class EntityMetadataWrapper {

  protected $type;

  protected $data;

  protected $info;

  protected $cache = array();

  /**

   * Construct a new wrapper object.

   *

   * @param $type

   *   The type of the passed data.

   * @param $data

   *   Optional. The data to wrap.

   * @param $info

   *   Optional. Used internally to pass info about properties down the tree.

   */

  public function __construct($type, $data = NULL, $info = array()) {

    $this->type = $type;

    $this->info = $info + array(

      'langcode' => NULL,

    );

    $this->info['type'] = $type;

    if (isset($data)) {

      $this->set($data);

    }

  }

  /**

   * Gets info about the wrapped data.

   *

   * @return Array

   *   Keys set are all keys as specified for a property in hook_entity_info()

   *   as well as possible the following keys:

   *    - name: If this wraps a property, the name of the property.

   *    - parent: The parent wrapper, if any.

   *    - langcode: The language code, if this data is language specific.

   */

  public function info() {

    return $this->info;

  }

  /**

   * Gets the (entity)type of the wrapped data.

   */

  public function type() {

    return $this->type;

  }

  /**

   * Returns the wrapped data. If no options are given the data is returned as

   * described in the info.

   *

   * @param $options

   *   (optional) A keyed array of options:

   *   - sanitize: A boolean flag indicating that textual properties should be

   *     sanitized for display to a web browser. Defaults to FALSE.

   *   - decode: If set to TRUE and some textual data is already sanitized, it

   *     strips HTML tags and decodes HTML entities. Defaults to FALSE.

   *

   *  @return

   *    The value of the wrapped data. If the data property is not set, NULL

   *    is returned.

   *

   *  @throws EntityMetadataWrapperException

   *    In case there are no data values available to the wrapper, an exception

   *    is thrown. E.g. if the value for an entity property is to be retrieved

   *    and there is no entity available, the exception is thrown. However, if

   *    an entity is available but the property is not set, NULL is returned.

   */

  public function value(array $options = array()) {

    if (!$this->dataAvailable() && isset($this->info['parent'])) {

      throw new EntityMetadataWrapperException('Missing data values.');

    }

    if (!isset($this->data) && isset($this->info['name'])) {

      $this->data = $this->info['parent']->getPropertyValue($this->info['name'], $this->info);

    }

    return $this->data;

  }

  /**

   * Returns the raw, unprocessed data. Most times this is the same as returned

   * by value(), however for already processed and sanitized textual data, this

   * will return the unprocessed data in contrast to value().

   */

  public function raw() {

    if (!$this->dataAvailable()) {

      throw new EntityMetadataWrapperException('Missing data values.');

    }

    if (isset($this->info['name']) && isset($this->info['parent'])) {

      return $this->info['parent']->getPropertyRaw($this->info['name'], $this->info);

    }

    // Else return the usual value, which should be raw in this case.

    return $this->value();

  }

  /**

   * Returns whether data is available to work with.

   *

   * @return

   *   If we operate without any data FALSE, else TRUE.

   */

  protected function dataAvailable() {

    return isset($this->data) || (isset($this->info['parent']) && $this->info['parent']->dataAvailable());

  }

  /**

   * Set a new data value.

   */

  public function set($value) {

    if (!$this->validate($value)) {

      throw new EntityMetadataWrapperException('Invalid data value given. Be sure it matches the required data type and format.');

    }

    $this->clear();

    $this->data = $value;

    $this->updateParent($value);

    return $this;

  }

  /**

   * Updates the parent data structure of a data property with the latest data value.

   */

  protected function updateParent($value) {

    if (isset($this->info['parent'])) {

      $this->info['parent']->setProperty($this->info['name'], $value);

    }

  }

  /**

   * Returns whether $value is a valid value to set.

   */

  public function validate($value) {

    if (isset($value) && !entity_property_verify_data_type($value, $this->type)) {

      return FALSE;

    }

    // Only proceed with further checks if this is not a list item. If this is

    // a list item, the checks are performed on the list property level.

    if (isset($this->info['parent']) && $this->info['parent'] instanceof EntityListWrapper) {

      return TRUE;

    }

    if (!isset($value) && !empty($this->info['required'])) {

      // Do not allow NULL values if the property is required.

      return FALSE;

    }

    return !isset($this->info['validation callback']) || call_user_func($this->info['validation callback'], $value, $this->info);

  }

  public function __toString() {

    return isset($this->info) ? 'Property ' . $this->info['name'] : $this->type;

  }

  /**

   * Clears the data value and the wrapper cache.

   */

  protected function clear() {

    $this->data = NULL;

    foreach ($this->cache as $wrapper) {

      $wrapper->clear();

    }

  }

  /**

   * Returns the options list specifying possible values for the property, if

   * defined.

   *

   * @param $op

   *   (optional) One of 'edit' or 'view'. In case the list of possible values

   *   a user could set for a property differs from the list of values a

   *   property could have, $op determines which options should be returned.

   *   Defaults to 'edit'.

   *   E.g. all possible roles a user could have include the anonymous and the

   *   authenticated user roles, while those roles cannot be added to a user

   *   account. So their options would be included for 'view', but for 'edit'

   *   not.

   *

   * @return

   *   An array as used by hook_options_list() or FALSE.

   */

  public function optionsList($op = 'edit') {

    if (isset($this->info['options list']) && is_callable($this->info['options list'])) {

      $name = isset($this->info['name']) ? $this->info['name'] : NULL;

      return call_user_func($this->info['options list'], $name, $this->info, $op);

    }

    return FALSE;

  }

  /**

   * Returns the label for the currently set property value if there is one

   * available, i.e. if an options list has been specified.

   */

  public function label() {

    if ($options = $this->optionsList('view')) {

      $options = entity_property_options_flatten($options);

      $value = $this->value();

      if (is_scalar($value) && isset($options[$value])) {

        return $options[$value];

      }

    }

  }

  /**

   * Determines whether the given user has access to view or edit this property.

   * Apart from relying on access metadata of properties, this takes into

   * account information about entity level access, if available:

   *  - Referenced entities can only be viewed, when the user also has

   *    permission to view the entity.

   *  - A property may be only edited, if the user has permission to update the

   *    entity containing the property.

   *

   * @param $op

   *   The operation being performed. One of 'view' or 'edit.

   * @param $account

   *   The user to check for. Leave it to NULL to check for the global user.

   * @return boolean

   *   Whether access to entity property is allowed for the given operation.

   *   However if we wrap no data, it returns whether access is allowed to the

   *   property of all entities of this type.

   *   If there is no access information for this property, TRUE is returned.

   */

  public function access($op, $account = NULL) {

    return !empty($this->info['parent']) ? $this->info['parent']->propertyAccess($this->info['name'], $op, $account) : TRUE;

  }

  /**

   * Prepare for serializiation.

   */

  public function __sleep() {

    $vars = get_object_vars($this);

    unset($vars['cache']);

    return drupal_map_assoc(array_keys($vars));

  }

}

/**

 * Wraps a single value.

 */

class EntityValueWrapper extends EntityMetadataWrapper {

  /**

   * Overrides EntityMetadataWrapper#value().

   * Sanitizes or decode textual data if necessary.

   */

  public function value(array $options = array()) {

    $data = parent::value();

    if ($this->type == 'text' && isset($data)) {

      $info = $this->info + array('sanitized' => FALSE, 'sanitize' => 'check_plain');

      $options += array('sanitize' => FALSE, 'decode' => FALSE);

      if ($options['sanitize'] && !$info['sanitized']) {

        return call_user_func($info['sanitize'], $data);

      }

      elseif ($options['decode'] && $info['sanitized']) {

        return decode_entities(strip_tags($data));

      }

    }

    return $data;

  }

}

/**

 * Provides a general wrapper for any data structure. For this to work the

 * metadata has to be passed during construction.

 */

class EntityStructureWrapper extends EntityMetadataWrapper implements IteratorAggregate {

  protected $propertyInfo = array(), $propertyInfoAltered = FALSE;

  protected $langcode = LANGUAGE_NONE;

  protected $propertyInfoDefaults = array(

    'type' => 'text',

    'getter callback' => 'entity_property_verbatim_get',

    'clear' => array(),

  );

  /**

   * Construct a new EntityStructureWrapper object.

   *

   * @param $type

   *   The type of the passed data.

   * @param $data

   *   Optional. The data to wrap.

   * @param $info

   *   Used to for specifying metadata about the data and internally to pass

   *   info about properties down the tree. For specifying metadata known keys

   *   are:

   *   - property info: An array of info about the properties of the wrapped

   *     data structure. It has to contain an array of property info in the same

   *     structure as used by hook_entity_property_info().

   */

  public function __construct($type, $data = NULL, $info = array()) {

    parent::__construct($type, $data, $info);

    $this->info += array('property defaults' => array());

    $info += array('property info' => array());

    $this->propertyInfo['properties'] = $info['property info'];

  }

  /**

   * May be used to lazy-load additional info about the data, depending on the

   * concrete passed data.

   */

  protected function spotInfo() {

    // Apply the callback if set, such that the caller may alter the info.

    if (!empty($this->info['property info alter']) && !$this->propertyInfoAltered) {

      $this->propertyInfo = call_user_func($this->info['property info alter'], $this, $this->propertyInfo);

      $this->propertyInfoAltered = TRUE;

    }

  }

  /**

   * Gets the info about the given property.

   *

   * @param $name

   *   The name of the property. If not given, info about all properties will

   *   be returned.

   * @throws EntityMetadataWrapperException

   *   If there is no such property.

   * @return

   *   An array of info about the property.

   */

  public function getPropertyInfo($name = NULL) {

    $this->spotInfo();

    if (!isset($name)) {

      return $this->propertyInfo['properties'];

    }

    if (!isset($this->propertyInfo['properties'][$name])) {

      throw new EntityMetadataWrapperException('Unknown data property ' . check_plain($name) . '.');

    }

    return $this->propertyInfo['properties'][$name] + $this->info['property defaults'] + $this->propertyInfoDefaults;

  }

  /**

   * Returns a reference on the property info.

   *

   * If possible, use the property info alter callback for spotting metadata.

   * The reference may be used to alter the property info for any remaining

   * cases, e.g. if additional metadata has been asserted.

   */

  public function &refPropertyInfo() {

    return $this->propertyInfo;

  }

  /**

   * Sets a new language to use for retrieving properties.

   *

   * @param $langcode

   *   The language code of the language to set.

   * @return EntityWrapper

   */

  public function language($langcode = LANGUAGE_NONE) {

    if ($langcode != $this->langcode) {

      $this->langcode = $langcode;

      $this->cache = array();

    }

    return $this;

  }

  /**

   * Gets the language used for retrieving properties.

   *

   * @return String

   *   The language object of the language or NULL for the default language.

   *

   * @see EntityStructureWrapper::language()

   */

  public function getPropertyLanguage() {

    if ($this->langcode != LANGUAGE_NONE && $list = language_list()) {

      if (isset($list[$this->langcode])) {

        return $list[$this->langcode];

      }

    }

    return NULL;

  }

  /**

   * Get the wrapper for a property.

   *

   * @return

   *   An instance of EntityMetadataWrapper.

   */

  public function get($name) {

    // Look it up in the cache if possible.

    if (!array_key_exists($name, $this->cache)) {

      if ($info = $this->getPropertyInfo($name)) {

        $info += array('parent' => $this, 'name' => $name, 'langcode' => $this->langcode, 'property defaults' => array());

        $info['property defaults'] += $this->info['property defaults'];

        $this->cache[$name] = entity_metadata_wrapper($info['type'], NULL, $info);

      }

      else {

        throw new EntityMetadataWrapperException('There is no property ' . check_plain($name) . " for this entity.");

      }

    }

    return $this->cache[$name];

  }

  /**

   * Magic method: Get a wrapper for a property.

   */

  public function __get($name) {

    if (strpos($name, 'krumo') === 0) {

      // #914934 Ugly workaround to allow krumo to write its recursion property.

      // This is necessary to make dpm() work without throwing exceptions.

      return NULL;

    }

    $get = $this->get($name);

    return $get;

  }

  /**

   * Magic method: Set a property.

   */

  public function __set($name, $value) {

    if (strpos($name, 'krumo') === 0) {

      // #914934 Ugly workaround to allow krumo to write its recursion property.

      // This is necessary to make dpm() work without throwing exceptions.

      $this->$name = $value;

    }

    else {

      $this->get($name)->set($value);

    }

  }

  /**

   * Gets the value of a property.

   */

  protected function getPropertyValue($name, &$info) {

    $options = array('language' => $this->getPropertyLanguage(), 'absolute' => TRUE);

    $data = $this->value();

    if (!isset($data)) {

      throw new EntityMetadataWrapperException('Unable to get the data property ' . check_plain($name) . ' as the parent data structure is not set.');

    }

    return $info['getter callback']($data, $options, $name, $this->type, $info);

  }

  /**

   * Gets the raw value of a property.

   */

  protected function getPropertyRaw($name, &$info) {

    if (!empty($info['raw getter callback'])) {

      $options = array('language' => $this->getPropertyLanguage(), 'absolute' => TRUE);

      $data = $this->value();

      if (!isset($data)) {

        throw new EntityMetadataWrapperException('Unable to get the data property ' . check_plain($name) . ' as the parent data structure is not set.');

      }

      return $info['raw getter callback']($data, $options, $name, $this->type, $info);

    }

    return $this->getPropertyValue($name, $info);

  }

  /**

   * Sets a property.

   */

  protected function setProperty($name, $value) {

    $info = $this->getPropertyInfo($name);

    if (!empty($info['setter callback'])) {

      $data = $this->value();

      // In case the data structure is not set, support simple auto-creation

      // for arrays. Else an exception is thrown.

      if (!isset($data)) {

        if (!empty($this->info['auto creation']) && !($this instanceof EntityDrupalWrapper)) {

          $data = $this->info['auto creation']($name, $this->info);

        }

        else {

          throw new EntityMetadataWrapperException('Unable to set the data property ' . check_plain($name) . ' as the parent data structure is not set.');

        }

      }

      // Invoke the setter callback for updating our data.

      $info['setter callback']($data, $name, $value, $this->langcode, $this->type, $info);

      // If the setter has not thrown any exceptions, proceed and apply the

      // update to the current and any parent wrappers as necessary.

      $data = $this->info['type'] == 'entity' ? $this : $data;

      $this->set($data);

      // Clear the cache of properties dependent on this value.

      foreach ($info['clear'] as $name) {

        if (isset($this->cache[$name])) {

          $this->cache[$name]->clear();

        }

      }

    }

    else {

      throw new EntityMetadataWrapperException('Entity property ' . check_plain($name) . " doesn't support writing.");

    }

  }

  protected function propertyAccess($name, $op, $account = NULL) {

    $info = $this->getPropertyInfo($name);

    // If a property should be edited and this is part of an entity, make sure

    // the user has update access for this entity.

    if ($op == 'edit') {

      $entity = $this;

      while (!($entity instanceof EntityDrupalWrapper) && isset($entity->info['parent'])) {

        $entity = $entity->info['parent'];

      }

      if ($entity instanceof EntityDrupalWrapper && $entity->entityAccess('update', $account) === FALSE) {

        return FALSE;

      }

    }

    if (!empty($info['access callback'])) {

      $data = $this->dataAvailable() ? $this->value() : NULL;

      return call_user_func($info['access callback'], $op, $name, $data, $account, $this->type);

    }

    elseif ($op == 'edit' && isset($info['setter permission'])) {

      return user_access($info['setter permission'], $account);

    }

    // If access is unknown, we return TRUE.

    return TRUE;

  }

  /**

   * Magic method: Can be used to check if a property is known.

   */

  public function __isset($name) {

    $this->spotInfo();

    return isset($this->propertyInfo['properties'][$name]);

  }

  public function getIterator() {

    $this->spotInfo();

    return new EntityMetadataWrapperIterator($this, array_keys($this->propertyInfo['properties']));

  }

  /**

   * Returns the identifier of the data structure. If there is none, NULL is

   * returned.

   */

  public function getIdentifier() {

    return isset($this->id) && $this->dataAvailable() ? $this->id->value() : NULL;

  }

  /**

   * Prepare for serializiation.

   */

  public function __sleep() {

    $vars = parent::__sleep();

    unset($vars['propertyInfoDefaults']);

    return $vars;

  }

  public function clear() {

    $this->propertyInfoAltered = FALSE;

    parent::clear();

  }

}

/**

 * Provides a wrapper for entities registrered in hook_entity_info().

 *

 * The wrapper eases applying getter and setter callbacks of entity properties

 * specified in hook_entity_property_info().

 */

class EntityDrupalWrapper extends EntityStructureWrapper {

  /**

   * Contains the entity id.

   */

  protected $id = FALSE;

  protected $bundle;

  protected $entityInfo;

  /**

   * Construct a new EntityDrupalWrapper object.

   *

   * @param $type

   *   The type of the passed data.

   * @param $data

   *   Optional. The entity to wrap or its identifier.

   * @param $info

   *   Optional. Used internally to pass info about properties down the tree.

   */

  public function __construct($type, $data = NULL, $info = array()) {

    parent::__construct($type, $data, $info);

    $this->setUp();

  }

  protected function setUp() {

    $this->propertyInfo = entity_get_property_info($this->type) + array('properties' => array());

    $info = $this->info + array('property info' => array(), 'bundle' => NULL);

    $this->propertyInfo['properties'] += $info['property info'];

    $this->bundle = $info['bundle'];

    $this->entityInfo = entity_get_info($this->type);

    if (isset($this->bundle)) {

      $this->spotBundleInfo(FALSE);

    }

  }

  /**

   * Sets the entity internally accepting both the entity id and object.

   */

  protected function setEntity($data) {

    // For entities we allow getter callbacks to return FALSE, which we

    // interpret like NULL values as unset properties.

    if (isset($data) && $data !== FALSE && !is_object($data)) {

      $this->id = $data;

      $this->data = FALSE;

    }

    elseif (is_object($data) && $data instanceof EntityDrupalWrapper) {

      // We got a wrapped entity passed, so take over its values.

      $this->id = $data->id;

      $this->data = $data->data;

      // For generic entity references, also update the entity type accordingly.

      if ($this->info['type'] == 'entity') {

        $this->type = $data->type;

      }

    }

    elseif (is_object($data)) {

      // We got the entity object passed.

      $this->data = $data;

      $id = entity_id($this->type, $data);

      $this->id = isset($id) ? $id : FALSE;

    }

    else {

      $this->id = FALSE;

      $this->data = NULL;

    }

  }

  /**

   * Used to lazy-load bundle info. So the wrapper can be loaded e.g. just

   * for setting without the data being loaded.

   */

  protected function spotInfo() {

    if (!$this->propertyInfoAltered) {

      if ($this->info['type'] == 'entity' && $this->dataAvailable() && $this->value()) {

        // Add in entity-type specific details.

        $this->setUp();

      }

      $this->spotBundleInfo(TRUE);

      parent::spotInfo();

      $this->propertyInfoAltered = TRUE;

    }

  }

  /**

   * Tries to determine the bundle and adds in the according property info.

   *

   * @param $load

   *   Whether the entity should be loaded to spot the info if necessary.

   */

  protected function spotBundleInfo($load = TRUE) {

    // Like entity_extract_ids() assume the entity type if no key is given.

    if (empty($this->entityInfo['entity keys']['bundle']) && $this->type != 'entity') {

      $this->bundle = $this->type;

    }

    // Detect the bundle if not set yet and add in properties from the bundle.

    elseif (!$this->bundle && $load && $this->dataAvailable()) {

      try {

        if ($entity = $this->value()) {

          list($id, $vid, $bundle) = entity_extract_ids($this->type, $entity);

          $this->bundle = $bundle;

        }

      }

      catch (EntityMetadataWrapperException $e) {

        // Loading data failed, so we cannot derive the used bundle.

      }

    }

    if ($this->bundle && isset($this->propertyInfo['bundles'][$this->bundle])) {

      $bundle_info = (array) $this->propertyInfo['bundles'][$this->bundle] + array('properties' => array());

      // Allow bundles to re-define existing properties, such that the bundle

      // can add in more bundle-specific details like the bundle of a referenced

      // entity.

      $this->propertyInfo['properties'] = $bundle_info['properties'] + $this->propertyInfo['properties'];

    }

  }

  /**

   * Returns the identifier of the wrapped entity.

   *

   * @see entity_id()

   */

  public function getIdentifier() {

    return $this->dataAvailable() ? $this->value(array('identifier' => TRUE)) : NULL;

  }

  /**

   * Returns the bundle of an entity, or FALSE if it has no bundles.

   */

  public function getBundle() {

    if ($this->dataAvailable()) {

      $this->spotInfo();

      return $this->bundle;

    }

  }

  /**

   * Overridden.

   *

   * @param $options

   *   An array of options. Known keys:

   *   - identifier: If set to TRUE, the entity identifier is returned.

   */

  public function value(array $options = array()) {

    // Try loading the data via the getter callback if there is none yet.

    if (!isset($this->data)) {

      $this->setEntity(parent::value());

    }

    if (!empty($options['identifier'])) {

      return $this->id;

    }

    elseif (!$this->data && !empty($this->id)) {

      // Lazy load the entity if necessary.

      $return = entity_load($this->type, array($this->id));

      // In case the entity cannot be loaded, we return NULL just as for empty

      // properties.

      $this->data = $return ? reset($return) : NULL;

    }

    return $this->data;

  }

  /**

   * Returns the entity prepared for rendering.

   *

   * @see entity_view()

   */

  public function view($view_mode = 'full', $langcode = NULL, $page = NULL) {

    return entity_view($this->type(), array($this->value()), $view_mode, $langcode, $page);

  }

  /**

   * Overridden to support setting the entity by either the object or the id.

   */

  public function set($value) {

    if (!$this->validate($value)) {

      throw new EntityMetadataWrapperException('Invalid data value given. Be sure it matches the required data type and format.');

    }

    if ($this->info['type'] == 'entity' && $value === $this) {

      // Nothing to do.

      return $this;

    }

    $previous_id = $this->id;

    $previous_type = $this->type;

    // Set value, so we get the identifier and pass it to the normal setter.

    $this->clear();

    $this->setEntity($value);

    // Generally, we have to update the parent only if the entity reference

    // has changed. In case of a generic entity reference, we pass the entity

    // wrapped. Else we just pass the id of the entity to the setter callback.

    if ($this->info['type'] == 'entity' && ($previous_id != $this->id || $previous_type != $this->type)) {

      // We need to clone the wrapper we pass through as value, so it does not

      // get cleared when the current wrapper instance gets cleared.

      $this->updateParent(clone $this);

    }

    // In case the entity has been unset, we cannot properly detect changes as

    // the previous id defaults to FALSE for unloaded entities too. So in that

    // case we just always update the parent.

    elseif ($this->id === FALSE && !$this->data) {

      $this->updateParent(NULL);

    }

    elseif ($previous_id !== $this->id) {

      $this->updateParent($this->id);

    }

    return $this;

  }

  /**

   * Overridden.

   */

  public function clear() {

    $this->id = NULL;

    $this->bundle = isset($this->info['bundle']) ? $this->info['bundle'] : NULL;

    if ($this->type != $this->info['type']) {

      // Reset entity info / property info based upon the info provided during

      // the creation of the wrapper.

      $this->type = $this->info['type'];

      $this->setUp();

    }

    parent::clear();

  }

  /**

   * Overridden.

   */

  public function type() {

    // In case of a generic entity wrapper, load the data first to determine

    // the type of the concrete entity.

    if ($this->dataAvailable() && $this->info['type'] == 'entity') {

      try {

        $this->value(array('identifier' => TRUE));

      }

      catch (EntityMetadataWrapperException $e) {

        // If loading data fails, we cannot determine the concrete entity type.

      }

    }

    return $this->type;

  }

  /**

   * {@inheritdoc}

   *

   * Note that this method checks property access, but can be used for checking

   * entity access *only* if the wrapper is not a property (i.e. has no parent

   * wrapper).

   * To be safe, better use EntityDrupalWrapper::entityAccess() for checking

   * entity access.

   */

  public function access($op, $account = NULL) {

    if (!empty($this->info['parent'])) {

      // If this is a property, make sure the user is able to view the

      // currently referenced entity also.

      if ($this->entityAccess('view', $account) === FALSE) {

        return FALSE;

      }

      if (parent::access($op, $account) === FALSE) {

        return FALSE;

      }

      // If access is unknown, we return TRUE.

      return TRUE;

    }

    else {

      // This is not a property, so fallback on entity access.

      return $this->entityAccess($op == 'edit' ? 'update' : 'view', $account);

    }

  }

  /**

   * Checks whether the operation $op is allowed on the entity.

   *

   * @see entity_access()

   */

  public function entityAccess($op, $account = NULL) {

    $entity = $this->dataAvailable() ? $this->value() : NULL;

    // The value() method could return FALSE on entities such as user 0, so we

    // need to use NULL instead to conform to the expectations of

    // entity_access().

    if ($entity === FALSE) {

      $entity = NULL;

    }

    return entity_access($op, $this->type, $entity, $account);

  }

  /**

   * Permanently save the wrapped entity.

   *

   * @throws EntityMetadataWrapperException

   *   If the entity type does not support saving.

   *

   * @return EntityDrupalWrapper

   */

  public function save() {

    if ($this->data) {

      if (!entity_type_supports($this->type, 'save')) {

        throw new EntityMetadataWrapperException("There is no information about how to save entities of type " . check_plain($this->type) . '.');

      }

      entity_save($this->type, $this->data);

      // On insert, update the identifier afterwards.

      if (!$this->id) {

        list($this->id, , ) = entity_extract_ids($this->type, $this->data);

      }

    }

    // If the entity hasn't been loaded yet, don't bother saving it.

    return $this;

  }

  /**

   * Permanently delete the wrapped entity.

   *

   * @return EntityDrupalWrapper

   */

  public function delete() {

    if ($this->dataAvailable() && $this->value()) {

      $return = entity_delete($this->type, $this->id);

      if ($return === FALSE) {

        throw new EntityMetadataWrapperException("There is no information about how to delete entities of type " . check_plain($this->type) . '.');

      }

    }

    return $this;

  }

  /**

   * Gets the info about the wrapped entity.

   */

  public function entityInfo() {

    return $this->entityInfo;

  }

  /**

   * Returns the name of the key used by the entity for given entity key.

   *

   * @param $name

   *   One of 'id', 'name', 'bundle' or 'revision'.

   * @return

   *   The name of the key used by the entity.

   */

  public function entityKey($name) {

    return isset($this->entityInfo['entity keys'][$name]) ? $this->entityInfo['entity keys'][$name] : FALSE;

  }

  /**

   * Returns the entity label.

   *

   * @see entity_label()

   */

  public function label() {

    if ($entity = $this->value()) {

      return entity_label($this->type, $entity);

    }

  }

  /**

   * Prepare for serializiation.

   */

  public function __sleep() {

    $vars = parent::__sleep();

    // Don't serialize the loaded entity and its property info.

    unset($vars['data'], $vars['propertyInfo'], $vars['propertyInfoAltered'], $vars['entityInfo']);

    // In case the entity is not saved yet, serialize the unsaved data.

    if ($this->dataAvailable() && $this->id === FALSE) {

      $vars['data'] = 'data';

    }

    return $vars;

  }

  public function __wakeup() {

    $this->setUp();

    if ($this->id !== FALSE) {

      // Make sure data is set, so the entity will be loaded when needed.

      $this->data = FALSE;

    }

  }

}

/**

 * Wraps a list of values.

 *

 * If the wrapped data is a list of data, its numerical indexes may be used to

 * retrieve wrappers for the list items. For that this wrapper implements

 * ArrayAccess so it may be used like a usual numerically indexed array.

 */

class EntityListWrapper extends EntityMetadataWrapper implements IteratorAggregate, ArrayAccess, Countable {

  /**

   * The type of contained items.

   */

  protected $itemType;

  /**

   * Whether this is a list of entities with a known entity type, i.e. for

   * generic list of entities (list<entity>) this is FALSE.

   */

  protected $isEntityList;

  public function __construct($type, $data = NULL, $info = array()) {

    parent::__construct($type, NULL, $info);

    $this->itemType = entity_property_list_extract_type($this->type);

    if (!$this->itemType) {

      $this->itemType = 'unknown';

    }

    $this->isEntityList = (bool) entity_get_info($this->itemType);

    if (isset($data)) {

      $this->set($data);

    }

  }

  /**

   * Get the wrapper for a single item.

   *

   * @return

   *   An instance of EntityMetadataWrapper.

   */

  public function get($delta) {

    // Look it up in the cache if possible.

    if (!array_key_exists($delta, $this->cache)) {

      if (!isset($delta)) {

        // The [] operator has been used so point at a new entry.

        $values = parent::value();

        $delta = $values ? max(array_keys($values)) + 1 : 0;

      }

      if (is_numeric($delta)) {

        $info = array('parent' => $this, 'name' => $delta) + $this->info;

        $this->cache[$delta] = entity_metadata_wrapper($this->itemType, NULL, $info);

      }

      else {

        throw new EntityMetadataWrapperException('There can be only numerical keyed items in a list.');

      }

    }

    return $this->cache[$delta];

  }

  protected function getPropertyValue($delta) {

    // Make use parent::value() to easily by-pass any entity-loading.

    $data = parent::value();

    if (isset($data[$delta])) {

      return $data[$delta];

    }

  }

  protected function getPropertyRaw($delta) {

    return $this->getPropertyValue($delta);

  }

  protected function setProperty($delta, $value) {

    $data = parent::value();

    if (is_numeric($delta)) {

      $data[$delta] = $value;

      $this->set($data);

    }

  }

  protected function propertyAccess($delta, $op, $account = NULL) {

    return $this->access($op, $account);

  }

  /**

   * Returns the list as numerically indexed array.

   *

   * Note that a list of entities might contain stale entity references. In

   * that case the wrapper and the identifier of a stale reference would be

   * still accessible, however the entity object value would be NULL. That way,

   * there may be NULL values in lists of entity objects due to stale entity

   * references.

   *

   * @param $options

   *   An array of options. Known keys:

   *   - identifier: If set to TRUE for a list of entities, it won't be returned

   *     as list of fully loaded entity objects, but as a list of entity ids.

   *     Note that this list may contain ids of stale entity references.

   */

  public function value(array $options = array()) {

    // For lists of entities fetch full entity objects before returning.

    // Generic entity-wrappers need to be handled separately though.

    if ($this->isEntityList && empty($options['identifier']) && $this->dataAvailable()) {

      $list = parent::value();

      $entities = $list ? entity_load($this->get(0)->type, $list) : array();

      // Make sure to keep the array keys as present in the list.

      foreach ($list as $key => $id) {

        // In case the entity cannot be loaded, we return NULL just as for empty

        // properties.

        $list[$key] = isset($entities[$id]) ? $entities[$id] : NULL;

      }

      return $list;

    }

    return parent::value();

  }

  public function set($values) {

    // Support setting lists of fully loaded entities.

    if ($this->isEntityList && $values && is_object(reset($values))) {

      foreach ($values as $key => $value) {

        // Ignore outdated NULL value references in lists of entities.

        if (isset($value)) {

          list($id, $vid, $bundle) = entity_extract_ids($this->itemType, $value);

          $values[$key] = $id;

        }

      }

    }

    return parent::set($values);

  }

  /**

   * If we wrap a list, we return an iterator over the data list.

   */

  public function getIterator() {

    // In case there is no data available, just iterate over the first item.

    return new EntityMetadataWrapperIterator($this, $this->dataAvailable() ? array_keys(parent::value()) : array(0));

  }

  /**

   * Implements the ArrayAccess interface.

   */

  public function offsetGet($delta) {

    return $this->get($delta);

  }

  public function offsetExists($delta) {

    return $this->dataAvailable() && ($data = $this->value()) && array_key_exists($delta, $data);

  }

  public function offsetSet($delta, $value) {

    $this->get($delta)->set($value);

  }

  public function offsetUnset($delta) {

    if ($this->offsetExists($delta)) {

      unset($this->data[$delta]);

      $this->set($this->data);

    }

  }

  public function count() {

    return $this->dataAvailable() ? count($this->value()) : 0;

  }

  /**

   * Overridden.

   */

  public function validate($value) {

    // Required lists may not be empty or unset.

    if (!empty($this->info['required']) && empty($value)) {

      return FALSE;

    }

    return parent::validate($value);

  }

  /**

   * Returns the label for the list of set values if available.

   */

  public function label() {

    if ($options = $this->optionsList('view')) {

      $options = entity_property_options_flatten($options);

      $labels = array_intersect_key($options, array_flip((array) parent::value()));

    }

    else {

      // Get each label on its own, e.g. to support getting labels of a list

      // of entities.

      $labels = array();

      foreach ($this as $key => $property) {

        $label = $property->label();

        if (!$label) {

          return NULL;

        }

        $labels[] = $label;

      }

    }

    return isset($labels) ? implode(', ', $labels) : NULL;

  }

}

/**

 * Provide a separate Exception so it can be caught separately.

 */

class EntityMetadataWrapperException extends Exception { }

/**

 * Allows to easily iterate over existing child wrappers.

 */

class EntityMetadataWrapperIterator implements RecursiveIterator {

  protected $position = 0;

  protected $wrapper, $keys;

  public function __construct(EntityMetadataWrapper $wrapper, array $keys) {

    $this->wrapper = $wrapper;

    $this->keys = $keys;

  }

  function rewind() {

    $this->position = 0;

  }

  function current() {

    return $this->wrapper->get($this->keys[$this->position]);

  }

  function key() {

    return $this->keys[$this->position];

  }

  function next() {

    $this->position++;

  }

  function valid() {

    return isset($this->keys[$this->position]);

  }

  public function hasChildren() {

    return $this->current() instanceof IteratorAggregate;

  }

  public function getChildren() {

    return $this->current()->getIterator();

  }

}

/**

 * An array object implementation keeping the reference on the given array so

 * changes to the object are reflected in the passed array.

 */

class EntityMetadataArrayObject implements ArrayAccess, Countable, IteratorAggregate {

  protected $data;

  public function __construct(&$array) {

    $this->data =& $array;

  }

  public function &getArray() {

    return $this->data;

  }

  /**

   * Implements the ArrayAccess interface.

   */

  public function offsetGet($delta) {

    return $this->data[$delta];

  }

  public function offsetExists($delta) {

    return array_key_exists($delta, $this->data);

  }

  public function offsetSet($delta, $value) {

    $this->data[$delta] = $value;

  }

  public function offsetUnset($delta) {

    unset($this->data[$delta]);

  }

  public function count() {

    return count($this->data);

  }

  public function getIterator() {

    return new ArrayIterator($this->data);

  }

}