field.module 42.8 KB
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<?php
/**
 * @file
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 * Attach custom data fields to Drupal entities.
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 */

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use Drupal\Core\Entity\EntityInterface;
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use Drupal\Core\Language\Language;
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use Drupal\Core\Template\Attribute;
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use Drupal\field\FieldInterface;
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use Drupal\field\FieldInstanceInterface;
use Drupal\Core\Entity\EntityNG;
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/*
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 * Load all public Field API functions. Drupal currently has no
 * mechanism for auto-loading core APIs, so we have to load them on
 * every page request.
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 */
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require_once __DIR__ . '/field.crud.inc';
require_once __DIR__ . '/field.info.inc';
require_once __DIR__ . '/field.multilingual.inc';
require_once __DIR__ . '/field.attach.inc';
require_once __DIR__ . '/field.form.inc';
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/**
 * @defgroup field Field API
 * @{
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 * Attaches custom data fields to Drupal entities.
 *
 * The Field API allows custom data fields to be attached to Drupal entities and
 * takes care of storing, loading, editing, and rendering field data. Any entity
 * type (node, user, etc.) can use the Field API to make itself "fieldable" and
 * thus allow fields to be attached to it. Other modules can provide a user
 * interface for managing custom fields via a web browser as well as a wide and
 * flexible variety of data type, form element, and display format capabilities.
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 *
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 * The Field API defines two primary data structures, Field and Instance, and
 * the concept of a Bundle. A Field defines a particular type of data that can
 * be attached to entities. A Field Instance is a Field attached to a single
 * Bundle. A Bundle is a set of fields that are treated as a group by the Field
 * Attach API and is related to a single fieldable entity type.
 *
 * For example, suppose a site administrator wants Article nodes to have a
 * subtitle and photo. Using the Field API or Field UI module, the administrator
 * creates a field named 'subtitle' of type 'text' and a field named 'photo' of
 * type 'image'. The administrator (again, via a UI) creates two Field
 * Instances, one attaching the field 'subtitle' to the 'node' bundle 'article'
 * and one attaching the field 'photo' to the 'node' bundle 'article'. When the
 * node system uses the Field Attach API to load all fields for an Article node,
 * it passes the node's entity type (which is 'node') and content type (which is
 * 'article') as the node's bundle. field_attach_load() then loads the
 * 'subtitle' and 'photo' fields because they are both attached to the 'node'
 * bundle 'article'.
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 *
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 * - @link field_types Field Types API @endlink: Defines field types, widget
 *   types, and display formatters. Field modules use this API to provide field
 *   types like Text and Node Reference along with the associated form elements
 *   and display formatters.
 *
 * - @link field_crud Field CRUD API @endlink: Create, updates, and deletes
 *   fields, bundles (a.k.a. "content types"), and instances. Modules use this
 *   API, often in hook_install(), to create custom data structures.
 *
 * - @link field_attach Field Attach API @endlink: Connects entity types to the
 *   Field API. Field Attach API functions load, store, generate Form API
 *   structures, display, and perform a variety of other functions for field
 *   data connected to individual entities. Fieldable entity types like node and
 *   user use this API to make themselves fieldable.
 *
 * - @link field_info Field Info API @endlink: Exposes information about all
 *   fields, instances, widgets, and related information defined by or with the
 *   Field API.
 *
 * - @link field_storage Field Storage API @endlink: Provides a pluggable back
 *   -end storage system for actual field data. The default implementation,
 *   field_sql_storage.module, stores field data in the local SQL database.
 *
 * - @link field_purge Field API bulk data deletion @endlink: Cleans up after
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 *   bulk deletion operations such as deletion of field or field_instance.
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 *
 * - @link field_language Field language API @endlink: Provides native
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 *   multilingual support for the Field API.
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 */

/**
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 * Value for field API indicating a field accepts an unlimited number of values.
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 */
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const FIELD_CARDINALITY_UNLIMITED = -1;
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/**
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 * Value for field API indicating a widget doesn't accept default values.
 *
 * @see hook_field_widget_info()
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 */
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const FIELD_BEHAVIOR_NONE = 0x0001;
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/**
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 * Value for field API concerning widget default and multiple value settings.
 *
 * @see hook_field_widget_info()
 *
 * When used in a widget default context, indicates the widget accepts default
 * values. When used in a multiple value context for a widget that allows the
 * input of one single field value, indicates that the widget will be repeated
 * for each value input.
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 */
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const FIELD_BEHAVIOR_DEFAULT = 0x0002;
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/**
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 * Value for field API indicating a widget can receive several field values.
 *
 * @see hook_field_widget_info()
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 */
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const FIELD_BEHAVIOR_CUSTOM = 0x0004;
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/**
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 * Load the most recent version of an entity's field data.
 *
 * @see field_attach_load().
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 */
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const FIELD_LOAD_CURRENT = 'FIELD_LOAD_CURRENT';
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/**
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 * Load the version of an entity's field data specified in the entity.
 *
 * @see field_attach_load().
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 */
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const FIELD_LOAD_REVISION = 'FIELD_LOAD_REVISION';
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/**
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 * Implements hook_help().
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 */
function field_help($path, $arg) {
  switch ($path) {
    case 'admin/help#field':
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      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
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      $output .= '<p>' . t('The Field module allows custom data fields to be defined for <em>entity</em> types (entities include content items, comments, user accounts, and taxonomy terms). The Field module takes care of storing, loading, editing, and rendering field data. Most users will not interact with the Field module directly, but will instead use the <a href="@field-ui-help">Field UI module</a> user interface. Module developers can use the Field API to make new entity types "fieldable" and thus allow fields to be attached to them. For more information, see the online handbook entry for <a href="@field">Field module</a>.', array('@field-ui-help' => url('admin/help/field_ui'), '@field' => 'http://drupal.org/documentation/modules/field')) . '</p>';
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      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Enabling field types') . '</dt>';
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      $output .= '<dd>' . t('The Field module provides the infrastructure for fields and field attachment; the field types and input widgets themselves are provided by additional modules. Some of the modules are required; the optional modules can be enabled from the <a href="@modules">Modules administration page</a>. Drupal core includes the following field type modules: Number (required), Text (required), List (required), Taxonomy (optional), Image (optional), and File (optional); the required Options module provides input widgets for other field modules. Additional fields and widgets may be provided by contributed modules, which you can find in the <a href="@contrib">contributed module section of Drupal.org</a>. Currently enabled field and input widget modules:', array('@modules' => url('admin/modules'), '@contrib' => 'http://drupal.org/project/modules', '@options' => url('admin/help/options')));
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      // Make a list of all widget and field modules currently enabled, in
      // order by displayed module name (module names are not translated).
      $items = array();
      $info = system_get_info('module');
      $modules = array_merge(module_implements('field_info'), module_implements('field_widget_info'));
      $modules = array_unique($modules);
      sort($modules);
      foreach ($modules as $module) {
        $display = $info[$module]['name'];
        if (module_hook($module, 'help')) {
          $items['items'][] = l($display, 'admin/help/' . $module);
        }
        else {
          $items['items'][] = $display;
        }
      }
      $output .= theme('item_list', $items) . '</dd>';
      $output .= '<dt>' . t('Managing field data storage') . '</dt>';
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      $output .= '<dd>' . t('Developers of field modules can either use the default <a href="@sql-store">Field SQL Storage module</a> to store data for their fields, or a contributed or custom module developed using the <a href="@storage-api">field storage API</a>.', array('@storage-api' => 'http://api.drupal.org/api/group/field_storage/8', '@sql-store' => url('admin/help/field_sql_storage'))) . '</dd>';
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      $output .= '</dl>';
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      return $output;
  }
}

/**
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 * Implements hook_theme().
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 */
function field_theme() {
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  return array(
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    'field' => array(
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      'render element' => 'element',
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    ),
    'field_multiple_value_form' => array(
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      'render element' => 'element',
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    ),
  );
}

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/**
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 * Implements hook_cron().
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 */
function field_cron() {
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  // Refresh the 'active' status of fields.
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  field_sync_field_status();
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  // Do a pass of purging on deleted Field API data, if any exists.
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  $limit = config('field.settings')->get('purge_batch_size');
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  field_purge_batch($limit);
}

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/**
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 * Implements hook_system_info_alter().
 *
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 * Goes through a list of all modules that provide a field type and makes them
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 * required if there are any active fields of that type.
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 */
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function field_system_info_alter(&$info, $file, $type) {
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  // It is not safe to call field_read_fields() during maintenance mode.
  if ($type == 'module' && module_hook($file->name, 'field_info') && !defined('MAINTENANCE_MODE')) {
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    $fields = field_read_fields(array('module' => $file->name), array('include_deleted' => TRUE));
    if ($fields) {
      $info['required'] = TRUE;

      // Provide an explanation message (only mention pending deletions if there
      // remains no actual, non-deleted fields)
      $non_deleted = FALSE;
      foreach ($fields as $field) {
        if (empty($field['deleted'])) {
          $non_deleted = TRUE;
          break;
        }
      }
      if ($non_deleted) {
        if (module_exists('field_ui')) {
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          $explanation = t('Field type(s) in use - see <a href="@fields-page">Field list</a>', array('@fields-page' => url('admin/reports/fields')));
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        }
        else {
          $explanation = t('Fields type(s) in use');
        }
      }
      else {
        $explanation = t('Fields pending deletion');
      }
      $info['explanation'] = $explanation;
    }
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  }
}

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/**
 * Implements hook_entity_create().
 */
function field_entity_create(EntityInterface $entity) {
  $info = $entity->entityInfo();
  if (!empty($info['fieldable'])) {
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    field_populate_default_values($entity, $entity->language()->id);
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  }
}

/**
 * Inserts a default value for each entity field not having one.
 *
 * @param \Drupal\Core\Entity\EntityInterface $entity
 *   The entity for the operation.
 * @param string $langcode
 *   (optional) The field language code to fill-in with the default value.
 *   Defaults to the entity language.
 */
function field_populate_default_values(EntityInterface $entity, $langcode = NULL) {
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  // Ensure we are working with a BC mode entity.
  $entity = $entity->getBCEntity();

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  $entity_type = $entity->entityType();
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  $langcode = $langcode ?: $entity->language()->id;
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  foreach (field_info_instances($entity_type, $entity->bundle()) as $field_name => $instance) {
    $field = field_info_field($field_name);
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    $field_langcode = field_is_translatable($entity_type, $field) ? $langcode : Language::LANGCODE_NOT_SPECIFIED;
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    // We need to preserve existing values.
    if (empty($entity->{$field_name}) || !array_key_exists($field_langcode, $entity->{$field_name})) {
      $items = field_get_default_value($entity, $field, $instance, $field_langcode);
      if (!empty($items)) {
        $entity->{$field_name}[$field_langcode] = $items;
      }
    }
  }
}

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/**
 * Implements hook_entity_field_info() to define all configured fields.
 */
function field_entity_field_info($entity_type) {
  $property_info = array();

  foreach (field_info_instances($entity_type) as $bundle_name => $instances) {
    $optional = $bundle_name != $entity_type;

    foreach ($instances as $field_name => $instance) {
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      $definition = _field_generate_entity_field_definition($instance->getField());
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      if ($optional) {
        $property_info['optional'][$field_name] = $definition;
        $property_info['bundle map'][$bundle_name][] = $field_name;
      }
      else {
        $property_info['definitions'][$field_name] = $definition;
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      }
    }
  }

  return $property_info;
}

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/**
 * Generates an entity field definition for a configurable field.
 *
 * @param \Drupal\field\FieldInterface $field
 *   The field definition.
 * @param \Drupal\field\FieldInstanceInterface $instance
 *   (Optional) The field instance definition.
 *
 * @return array
 *   The entity field definition.
 */
function _field_generate_entity_field_definition(FieldInterface $field, FieldInstanceInterface $instance = NULL) {
  // @todo: Allow for adding field type settings.
  $definition = array(
    'label' => t('Field !name', array('!name' => $field->id())),
    'type' => 'field_item:' . $field->type,
    'list' => TRUE,
    'configurable' => TRUE,
    'translatable' => !empty($field->translatable),
  );
  if ($instance) {
    $definition['instance'] = $instance;
  }

  return $definition;
}

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/**
 * Implements hook_field_widget_info_alter().
 */
function field_field_widget_info_alter(&$info) {
  // Add the Hidden widget to all field types.
  $info['hidden']['field_types'] = array_keys(field_info_field_types());
}

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/**
 * Applies language fallback rules to the fields attached to the given entity.
 *
 * Core language fallback rules simply check if fields have a field translation
 * for the requested language code. If so, the requested language is returned,
 * otherwise all the fallback candidates are inspected to see if there is a
 * field translation available in another language.
 * By default this is called by field_field_language_alter(), but this
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 * behavior can be disabled by setting the 'field.settings.language_fallback'
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 * variable to FALSE.
 *
 * @param $field_langcodes
 *   A reference to an array of language codes keyed by field name.
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 * @param \Drupal\Core\Entity\EntityInterface $entity
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 *   The entity to be displayed.
 * @param $langcode
 *   The language code $entity has to be displayed in.
 */
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function field_language_fallback(&$field_langcodes, EntityInterface $entity, $langcode) {
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  // Lazily init fallback candidates to avoid unnecessary calls.
  $fallback_candidates = NULL;

  foreach ($field_langcodes as $field_name => $field_langcode) {
    // If the requested language is defined for the current field use it,
    // otherwise search for a fallback value among the fallback candidates.
    if (isset($entity->{$field_name}[$langcode])) {
      $field_langcodes[$field_name] = $langcode;
    }
    elseif (!empty($entity->{$field_name})) {
      if (!isset($fallback_candidates)) {
        require_once DRUPAL_ROOT . '/core/includes/language.inc';
        $fallback_candidates = language_fallback_get_candidates();
      }
      foreach ($fallback_candidates as $fallback_langcode) {
        if (isset($entity->{$field_name}[$fallback_langcode])) {
          $field_langcodes[$field_name] = $fallback_langcode;
          break;
        }
      }
    }
  }
}

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/**
 * Implements hook_rebuild().
 */
function field_rebuild() {
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  // Refresh the 'active' status of fields.
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  field_sync_field_status();
}

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/**
 * Implements hook_modules_enabled().
 */
function field_modules_enabled($modules) {
  // Refresh the 'active' status of fields.
  field_sync_field_status();
}

/**
 * Implements hook_modules_disabled().
 */
function field_modules_disabled($modules) {
  // Refresh the 'active' status of fields.
  field_sync_field_status();
}

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/**
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 * Refreshes the 'active' and 'storage[active]' values for fields.
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 */
function field_sync_field_status() {
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  $module_handler = Drupal::moduleHandler();
  $state = Drupal::state();

  // Get both deleted and non-deleted field definitions.
  $fields = array();
  foreach (config_get_storage_names_with_prefix('field.field') as $name) {
    $field = Drupal::config($name)->get();
    $fields[$field['uuid']] = $field;
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  }
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  $deleted_fields = $state->get('field.field.deleted') ?: array();
  $fields += $deleted_fields;
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  if (empty($fields)) {
    return;
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  }
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  // Set the 'module' and 'active' values for the current set of enabled
  // modules.
  $changed = array();
  $modules = $module_handler->getModuleList();
  foreach ($modules as $module => $module_info) {
    // Collect field types and storage backends exposed by the module.
    $field_types = (array) $module_handler->invoke($module, 'field_info');
    $storage_types = (array) $module_handler->invoke($module, 'field_storage_info');

    if ($field_types || $storage_types) {
      foreach ($fields as $uuid => &$field) {
        // Associate field types.
        if (isset($field_types[$field['type']]) && ($field['module'] !== $module || !$field['active'])) {
          $field['module'] = $module;
          $field['active'] = TRUE;
          $changed[$uuid] = $field;
        }
        // Associate storage backends.
        if (isset($storage_types[$field['storage']['type']]) && ($field['storage']['module'] !== $module || !$field['storage']['active'])) {
          $field['storage']['module'] = $module;
          $field['storage']['active'] = TRUE;
          $changed[$uuid] = $field;
        }
      }
    }
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  }
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  // Set fields with missing field type or storage modules to inactive.
  foreach ($fields as $uuid => &$field) {
    if (!isset($modules[$field['module']]) && $field['active']) {
      $field['active'] = FALSE;
      $changed[$uuid] = $field;
    }
    if (!isset($modules[$field['storage']['module']]) && $field['storage']['active']) {
      $field['storage']['active'] = FALSE;
      $changed[$uuid] = $field;
    }
  }

  // Store the updated field definitions.
  foreach ($changed as $uuid => $field) {
    if (!empty($field['deleted'])) {
      $deleted_fields[$uuid] = $field;
    }
    else {
      Drupal::config('field.field.' . $field['id'])
        ->set('module', $field['module'])
        ->set('active', $field['active'])
        ->set('storage.module', $field['storage']['module'])
        ->set('storage.active', $field['storage']['active'])
        ->save();
    }
  }
  $state->set('field.field.deleted', $deleted_fields);

  field_cache_clear();
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}

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/**
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 * Helper function to get the default value for a field on an entity.
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 *
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 * @param \Drupal\Core\Entity\EntityInterface $entity
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 *   The entity for the operation.
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 * @param $field
 *   The field structure.
 * @param $instance
 *   The instance structure.
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 * @param $langcode
 *   The field language to fill-in with the default value.
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 */
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function field_get_default_value(EntityInterface $entity, $field, $instance, $langcode = NULL) {
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  $items = array();
  if (!empty($instance['default_value_function'])) {
    $function = $instance['default_value_function'];
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    $items = $function($entity, $field, $instance, $langcode);
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  }
  elseif (!empty($instance['default_value'])) {
    $items = $instance['default_value'];
  }
  return $items;
}

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/**
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 * Callback for usort() within theme_field_multiple_value_form().
 *
 * Sorts using ['_weight']['#value']
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 */
function _field_sort_items_value_helper($a, $b) {
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  $a_weight = (is_array($a) && isset($a['_weight']['#value']) ? $a['_weight']['#value'] : 0);
  $b_weight = (is_array($b) && isset($b['_weight']['#value']) ? $b['_weight']['#value'] : 0);
  return $a_weight - $b_weight;
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}

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/**
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 * Gets or sets administratively defined bundle settings.
 *
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 * @param string $entity_type
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 *   The type of $entity; e.g., 'node' or 'user'.
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 * @param string $bundle
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 *   The bundle name.
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 * @param array|null $settings
 *   (optional) The settings to store, an associative array with the following
 *   elements:
 *   - view_modes: An associative array keyed by view mode, with the following
 *     key/value pairs:
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 *     - status: Boolean specifying whether the view mode uses a dedicated set
 *       of display options (TRUE), or the 'default' options (FALSE). Defaults
 *       to FALSE.
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 *   - extra_fields: An associative array containing the form and display
 *     settings for extra fields (also known as pseudo-fields):
 *     - form: An associative array whose keys are the names of extra fields,
 *       and whose values are associative arrays with the following elements:
 *       - weight: The weight of the extra field, determining its position on an
 *         entity form.
 *     - display: An associative array whose keys are the names of extra fields,
 *       and whose values are associative arrays keyed by the name of view
 *       modes. This array must include an item for the 'default' view mode.
 *       Each view mode sub-array contains the following elements:
 *       - weight: The weight of the extra field, determining its position when
 *         an entity is viewed.
 *       - visible: TRUE if the extra field is visible, FALSE otherwise.
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 *
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 * @return array|null
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 *   If no $settings are passed, the current settings are returned.
 */
function field_bundle_settings($entity_type, $bundle, $settings = NULL) {
  if (isset($settings)) {
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    variable_set('field_bundle_settings_' . $entity_type . '__' . $bundle, $settings);
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    field_info_cache_clear();
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  }
  else {
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    $settings = variable_get('field_bundle_settings_' . $entity_type . '__' . $bundle, array());
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    $settings += array(
      'view_modes' => array(),
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      'form_modes' => array(),
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    );
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    return $settings;
  }
}

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/**
 * Returns form mode settings in a given bundle.
 *
 * @param string $entity_type
 *   The type of entity; e.g. 'node' or 'user'.
 * @param string $bundle
 *   The bundle name to return form mode settings for.
 *
 * @return
 *   An array keyed by form mode, with the following key/value pairs:
 *   - status: Boolean specifying whether the form mode uses a dedicated set of
 *     display options (TRUE), or the 'default' options (FALSE). Defaults to
 *     FALSE.
 */
function field_form_mode_settings($entity_type, $bundle) {
  $cache = &drupal_static(__FUNCTION__, array());

  if (!isset($cache[$entity_type][$bundle])) {
    $bundle_settings = field_bundle_settings($entity_type, $bundle);
    $settings = $bundle_settings['form_modes'];
    // Include form modes for which nothing has been stored yet, but whose
    // definition in hook_entity_info_alter() specify they should use custom
    // settings by default.
    $form_modes = entity_get_form_modes($entity_type);
    foreach ($form_modes as $form_mode => $form_mode_info) {
      if (!isset($settings[$form_mode]['status']) && $form_mode_info['status']) {
        $settings[$form_mode]['status'] = TRUE;
      }
    }
    $cache[$entity_type][$bundle] = $settings;
  }

  return $cache[$entity_type][$bundle];
}

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/**
 * Returns view mode settings in a given bundle.
 *
 * @param $entity_type
 *   The type of entity; e.g. 'node' or 'user'.
 * @param $bundle
 *   The bundle name to return view mode settings for.
 *
 * @return
 *   An array keyed by view mode, with the following key/value pairs:
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 *   - status: Boolean specifying whether the view mode uses a dedicated set of
 *     display options (TRUE), or the 'default' options (FALSE). Defaults to
 *     FALSE.
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 */
function field_view_mode_settings($entity_type, $bundle) {
  $cache = &drupal_static(__FUNCTION__, array());

  if (!isset($cache[$entity_type][$bundle])) {
    $bundle_settings = field_bundle_settings($entity_type, $bundle);
    $settings = $bundle_settings['view_modes'];
    // Include view modes for which nothing has been stored yet, but whose
614 615
    // definition in hook_entity_info_alter() specify they should use custom
    // settings by default.
616 617
    $view_modes = entity_get_view_modes($entity_type);
    foreach ($view_modes as $view_mode => $view_mode_info) {
618 619
      if (!isset($settings[$view_mode]['status']) && $view_mode_info['status']) {
        $settings[$view_mode]['status'] = TRUE;
620 621 622 623 624 625 626 627
      }
    }
    $cache[$entity_type][$bundle] = $settings;
  }

  return $cache[$entity_type][$bundle];
}

628
/**
629
 * Clears the field info and field data caches.
630
 */
631
function field_cache_clear() {
632
  cache('field')->deleteAll();
633
  field_info_cache_clear();
634 635 636
}

/**
637 638
 * Filters an HTML string to prevent cross-site-scripting (XSS) vulnerabilities.
 *
639 640
 * Like filter_xss_admin(), but with a shorter list of allowed tags.
 *
641 642 643 644 645 646 647 648 649 650
 * Used for items entered by administrators, like field descriptions, allowed
 * values, where some (mainly inline) mark-up may be desired (so
 * drupal_htmlspecialchars() is not acceptable).
 *
 * @param $string
 *   The string with raw HTML in it.
 *
 * @return
 *   An XSS safe version of $string, or an empty string if $string is not valid
 *   UTF-8.
651 652
 */
function field_filter_xss($string) {
653
  return _filter_htmlcorrector(filter_xss($string, _field_filter_xss_allowed_tags()));
654 655 656
}

/**
657
 * Returns a list of tags allowed by field_filter_xss().
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 */
function _field_filter_xss_allowed_tags() {
  return array('a', 'b', 'big',  'code', 'del', 'em', 'i', 'ins',  'pre', 'q', 'small', 'span', 'strong', 'sub', 'sup', 'tt', 'ol', 'ul', 'li', 'p', 'br', 'img');
}

/**
664
 * Returns a human-readable list of allowed tags for display in help texts.
665 666 667 668 669 670
 */
function _field_filter_xss_display_allowed_tags() {
  return '<' . implode('> <', _field_filter_xss_allowed_tags()) . '>';
}

/**
671
 * Returns a renderable array for a single field value.
672
 *
673
 * @param \Drupal\Core\Entity\EntityInterface $entity
674
 *   The entity containing the field to display. Must at least contain the ID
675 676 677
 *   key and the field data to display.
 * @param $field_name
 *   The name of the field to display.
678
 * @param $item
679 680 681
 *   The field value to display, as found in
 *   $entity->field_name[$langcode][$delta].
 * @param $display
682 683
 *   Can be either the name of a view mode, or an array of display settings. See
 *   field_view_field() for more information.
684
 * @param $langcode
685 686 687
 *   (Optional) The language of the value in $item. If not provided, the current
 *   language will be assumed.
 *
688
 * @return
689
 *   A renderable array for the field value.
690
 */
691
function field_view_value(EntityInterface $entity, $field_name, $item, $display = array(), $langcode = NULL) {
692
  $output = array();
693

694 695 696
  // Ensure we are working with a BC mode entity.
  $entity = $entity->getBCEntity();

697 698
  if ($field = field_info_field($field_name)) {
    // Determine the langcode that will be used by language fallback.
699
    $langcode = field_language($entity, $field_name, $langcode);
700

701 702 703 704
    // Push the item as the single value for the field, and defer to
    // field_view_field() to build the render array for the whole field.
    $clone = clone $entity;
    $clone->{$field_name}[$langcode] = array($item);
705
    $elements = field_view_field($clone, $field_name, $display, $langcode);
706

707 708 709 710
    // Extract the part of the render array we need.
    $output = isset($elements[0]) ? $elements[0] : array();
    if (isset($elements['#access'])) {
      $output['#access'] = $elements['#access'];
711 712
    }
  }
713 714

  return $output;
715 716 717
}

/**
718
 * Returns a renderable array for the value of a single field in an entity.
719
 *
720
 * The resulting output is a fully themed field with label and multiple values.
721
 *
722 723 724 725
 * This function can be used by third-party modules that need to output an
 * isolated field.
 * - Do not use inside node (or other entities) templates, use
 *   render($content[FIELD_NAME]) instead.
726
 * - Do not use to display all fields in an entity, use
727
 *   field_attach_prepare_view() and field_attach_view() instead.
728 729
 * - The field_view_value() function can be used to output a single formatted
 *   field value, without label or wrapping field markup.
730
 *
731 732 733
 * The function takes care of invoking the prepare_view steps. It also respects
 * field access permissions.
 *
734 735
 * @param \Drupal\Core\Entity\EntityInterface $entity
 *   The entity containing the field to display.
736 737
 * @param $field_name
 *   The name of the field to display.
738
 * @param $display_options
739
 *   Can be either:
740 741
 *   - The name of a view mode. The field will be displayed according to the
 *     display settings specified for this view mode in the $instance
742 743 744
 *     definition for the field in the entity's bundle. If no display settings
 *     are found for the view mode, the settings for the 'default' view mode
 *     will be used.
745
 *   - An array of display options. The following key/value pairs are allowed:
746 747 748 749
 *     - label: (string) Position of the label. The default 'field' theme
 *       implementation supports the values 'inline', 'above' and 'hidden'.
 *       Defaults to 'above'.
 *     - type: (string) The formatter to use. Defaults to the
750 751
 *       'default_formatter' for the field type. The default formatter will also
 *       be used if the requested formatter is not available.
752
 *     - settings: (array) Settings specific to the formatter. Defaults to the
753
 *       formatter's default settings.
754 755 756
 *     - weight: (float) The weight to assign to the renderable element.
 *       Defaults to 0.
 * @param $langcode
757 758
 *   (Optional) The language code the field values are to be shown in. The
 *   site's current language fallback logic will be applied when no values are
759
 *   available for the given language code. If no language code is provided the
760
 *   current language will be used.
761
 *
762
 * @return
763
 *   A renderable array for the field value.
764 765
 *
 * @see field_view_value()
766
 */
767
function field_view_field(EntityInterface $entity, $field_name, $display_options = array(), $langcode = NULL) {
768
  $output = array();
769
  $bundle = $entity->bundle();
770
  $entity_type = $entity->entityType();
771

772
  // Return nothing if the field doesn't exist.
773
  $instance = field_info_instance($entity_type, $field_name, $bundle);
774 775 776 777 778 779 780
  if (!$instance) {
    return $output;
  }

  // Get the formatter object.
  if (is_string($display_options)) {
    $view_mode = $display_options;
781
    $formatter = entity_get_render_display($entity, $view_mode)->getRenderer($field_name);
782 783 784 785 786 787 788 789 790
  }
  else {
    $view_mode = '_custom';
    // hook_field_attach_display_alter() needs to receive the 'prepared'
    // $display_options, so we cannot let preparation happen internally.
    $field = field_info_field($field_name);
    $formatter_manager = drupal_container()->get('plugin.manager.field.formatter');
    $display_options = $formatter_manager->prepareConfiguration($field['type'], $display_options);
    $formatter = $formatter_manager->getInstance(array(
791
      'field_definition' => $instance,
792 793 794 795 796 797 798
      'view_mode' => $view_mode,
      'prepare' => FALSE,
      'configuration' => $display_options,
    ));
  }

  if ($formatter) {
799
    $display_langcode = field_language($entity, $field_name, $langcode);
800 801 802 803 804 805 806 807 808 809 810

    // Get the items.
    if ($entity->getNGEntity() instanceof EntityNG) {
      $items = $entity->getTranslation($display_langcode)->get($field_name);
      $definition = $entity->getPropertyDefinition($field_name);
    }
    else {
      $definitions = \Drupal::entityManager()->getFieldDefinitions($entity_type, $bundle);
      $definition = $definitions[$field_name];
      $itemsBC = isset($entity->{$field_name}[$display_langcode]) ? $entity->{$field_name}[$display_langcode] : array();
      $items = \Drupal::typedData()->create($definitions[$field_name], $itemsBC, $field_name, $entity);
811
    }
812

813
    // Invoke the formatter's prepareView() and view() methods.
814 815 816 817 818
    $id = $entity->id();
    $itemsBC_multi = array($id => $items->getValue());
    $formatter->prepareView(array($id => $entity), $display_langcode, $itemsBC_multi);
    $itemsBC = $itemsBC_multi[$id];
    $result = $formatter->view($entity, $display_langcode, $itemsBC);
819

820 821 822 823 824 825
    // Invoke hook_field_attach_view_alter() to let other modules alter the
    // renderable array, as in a full field_attach_view() execution.
    $context = array(
      'entity' => $entity,
      'view_mode' => $view_mode,
      'display_options' => $display_options,
826
      'langcode' => $display_langcode,
827 828
    );
    drupal_alter('field_attach_view', $result, $context);
829

830 831
    if (isset($result[$field_name])) {
      $output = $result[$field_name];
832
    }
833
  }
834

835 836 837
  return $output;
}

838 839 840
/**
 * Returns the field items in the language they currently would be displayed.
 *
841
 * @param \Drupal\Core\Entity\EntityInterface $entity
842 843 844 845 846 847 848 849
 *   The entity containing the data to be displayed.
 * @param $field_name
 *   The field to be displayed.
 * @param $langcode
 *   (optional) The language code $entity->{$field_name} has to be displayed in.
 *   Defaults to the current language.
 *
 * @return
850
 *   An array with available field items keyed by delta.
851
 */
852
function field_get_items(EntityInterface $entity, $field_name, $langcode = NULL) {
853
  $entity = $entity->getBCEntity();
854
  $langcode = field_language($entity, $field_name, $langcode);
855
  return isset($entity->{$field_name}[$langcode]) ? $entity->{$field_name}[$langcode] : array();
856 857
}

858
/**
859
 * Determines whether the user has access to a given field.
860
 *
861
 * @param string $op
862
 *   The operation to be performed. Possible values:
863 864
 *   - edit
 *   - view
865 866
 * @param \Drupal\field\FieldInterface $field
 *   The field on which the operation is to be performed.
867 868
 * @param $entity_type
 *   The type of $entity; for example, 'node' or 'user'.
869
 * @param $entity
870
 *   (optional) The entity for the operation.
871 872
 * @param $account
 *   (optional) The account to check, if not given use currently logged in user.
873
 *
874
 * @return
875
 *   TRUE if the operation is allowed; FALSE if the operation is denied.
876
 */
877
function field_access($op, FieldInterface $field, $entity_type, $entity = NULL, $account = NULL) {
878 879
  global $user;

880
  if (!isset($account)) {
881 882 883
    $account = $user;
  }

884 885
  foreach (module_implements('field_access') as $module) {
    $function = $module . '_field_access';
886
    $access = $function($op, $field, $entity_type, $entity, $account);
887
    if ($access === FALSE) {
888 889 890 891 892 893
      return FALSE;
    }
  }
  return TRUE;
}

894
/**
895
 * Extracts the bundle name from a bundle object.
896
 *
897
 * @param $entity_type
898
 *   The type of $entity; e.g., 'node' or 'user'.
899
 * @param $bundle
900
 *   The bundle object (or string if bundles for this entity type do not exist
901
 *   as standalone objects).
902
 *
903 904 905
 * @return
 *   The bundle name.
 */
906
function field_extract_bundle($entity_type, $bundle) {
907 908 909 910
  if (is_string($bundle)) {
    return $bundle;
  }

911
  $info = entity_get_info($entity_type);
912 913
  if (is_object($bundle) && isset($info['bundle_keys']['bundle']) && isset($bundle->{$info['bundle_keys']['bundle']})) {
    return $bundle->{$info['bundle_keys']['bundle']};
914 915 916
  }
}

917 918 919 920 921
/**
 * Implements hook_page_build().
 */
function field_page_build(&$page) {
  $path = drupal_get_path('module', 'field');
922
  $page['#attached']['css'][$path . '/css/field.module.css'] = array('every_page' => TRUE);
923 924
}

925
/**
926
 * Prepares variables for field templates.
927
 *
928 929 930 931 932 933 934 935 936
 * Default template: field.html.twig.
 *
 * @param array $variables
 *   An associative array containing:
 *   - element: A render element representing the field.
 *   - attributes: A string containing the attributes for the wrapping div.
 *   - title_attributes: A string containing the attributes for the title.
 *   - content_attributes: A string containing the attributes for the content's
 *     div.
937
 */
938
function template_preprocess_field(&$variables, $hook) {
939 940
  $element = $variables['element'];

941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966
  // There's some overhead in calling check_plain() so only call it if the label
  // variable is being displayed. Otherwise, set it to NULL to avoid PHP
  // warnings if a theme implementation accesses the variable even when it's
  // supposed to be hidden. If a theme implementation needs to print a hidden
  // label, it needs to supply a preprocess function that sets it to the
  // sanitized element title or whatever else is wanted in its place.
  $variables['label_hidden'] = ($element['#label_display'] == 'hidden');
  $variables['label'] = $variables['label_hidden'] ? NULL : check_plain($element['#title']);

  // We want other preprocess functions and the theme implementation to have
  // fast access to the field item render arrays. The item render array keys
  // (deltas) should always be a subset of the keys in #items, and looping on
  // those keys is faster than calling element_children() or looping on all keys
  // within $element, since that requires traversal of all element properties.
  $variables['items'] = array();
  foreach ($element['#items'] as $delta => $item) {
    if (!empty($element[$delta])) {
      $variables['items'][$delta] = $element[$delta];
    }
  }

  // Add default CSS classes. Since there can be many fields rendered on a page,
  // save some overhead by calling strtr() directly instead of
  // drupal_html_class().
  $variables['field_name_css'] = strtr($element['#field_name'], '_', '-');
  $variables['field_type_css'] = strtr($element['#field_type'], '_', '-');
967
  $variables['attributes']['class'] = array(
968 969 970 971
    'field',
    'field-name-' . $variables['field_name_css'],
    'field-type-' . $variables['field_type_css'],
    'field-label-' . $element['#label_display'],
972
  );
973
  // Add a "clearfix" class to the wrapper since we float the label and the
974
  // field items in field.module.css if the label is inline.
975
  if ($element['#label_display'] == 'inline') {
976
    $variables['attributes']['class'][] = 'clearfix';
977
  }
978

979 980
  // Add specific suggestions that can override the default implementation.
  $variables['theme_hook_suggestions'] = array(
981
    'field__' . $element['#field_type'],
982 983 984 985
    'field__' . $element['#field_name'],
    'field__' . $element['#bundle'],
    'field__' . $element['#field_name'] . '__' . $element['#bundle'],
  );
986 987
}

988
/**
989
 * Theme process function for theme_field() and field.html.twig.