field.module 38.1 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;
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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.info.inc';
require_once __DIR__ . '/field.multilingual.inc';
require_once __DIR__ . '/field.attach.inc';
require_once __DIR__ . '/field.form.inc';
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require_once __DIR__ . '/field.purge.inc';
require_once __DIR__ . '/field.deprecated.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
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 * node storage controller loads an Article node, it loads the values of the
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 * '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_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.
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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.
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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');
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      $modules = array_merge(Drupal::moduleHandler()->getImplementations('field_info'), Drupal::moduleHandler()->getImplementations('field_widget_info'));
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      $modules = array_unique($modules);
      sort($modules);
      foreach ($modules as $module) {
        $display = $info[$module]['name'];
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        if (Drupal::moduleHandler()->implementsHook($module, 'help')) {
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          $items['items'][] = l($display, 'admin/help/' . $module);
        }
        else {
          $items['items'][] = $display;
        }
      }
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      $item_list = array(
        '#theme' => 'item_list',
        '#items' => $items['items'],
      );
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      $output .= drupal_render($item_list);
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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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  $limit = Drupal::config('field.settings')->get('purge_batch_size');
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  field_purge_batch($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, $type) {
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  // It is not safe to call field_read_fields() during maintenance mode.
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  if ($type == 'module' && !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_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(
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    'label' => t('Field !name', array('!name' => $field->name)),
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    '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.
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  $info['hidden']['field_types'] = array_keys(\Drupal::service('plugin.manager.entity.field.field_type')->getDefinitions());
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}

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/**
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 * Implements hook_entity_bundle_create().
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 */
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function field_entity_bundle_create($entity_type, $bundle) {
  // Clear the cache.
  field_cache_clear();
}
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/**
 * Implements hook_entity_bundle_rename().
 */
function field_entity_bundle_rename($entity_type, $bundle_old, $bundle_new) {
  $instances = field_read_instances();
  foreach ($instances as $instance) {
    if ($instance->entity_type == $entity_type && $instance->bundle == $bundle_old) {
      $id_new = $instance['entity_type'] . '.' . $bundle_new . '.' . $instance['field_name'];
      $instance->id = $id_new;
      $instance->bundle = $bundle_new;
      $instance->allowBundleRename();
      $instance->save();
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    }
  }
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  // Clear the field cache.
  field_cache_clear();

  // Update bundle settings.
  $settings = variable_get('field_bundle_settings_' . $entity_type . '__' . $bundle_old, array());
  variable_set('field_bundle_settings_' . $entity_type . '__' . $bundle_new, $settings);
  variable_del('field_bundle_settings_' . $entity_type . '__' . $bundle_old);
}

/**
 * Implements hook_entity_bundle_delete().
 *
 * This deletes the data for the field instances as well as the field instances
 * themselves. This function actually just marks the data and field instances as
 * deleted, leaving the garbage collection for a separate process, because it is
 * not always possible to delete this much data in a single page request
 * (particularly since for some field types, the deletion is more than just a
 * simple DELETE query).
 */
function field_entity_bundle_delete($entity_type, $bundle) {
  // Get the instances on the bundle. field_read_instances() must be used
  // here since field_info_instances() does not return instances for disabled
  // entity types or bundles.
  $instances = field_read_instances(array('entity_type' => $entity_type, 'bundle' => $bundle), array('include_inactive' => TRUE));
  foreach ($instances as $instance) {
    $instance->delete();
  }

  // Clear the cache.
  field_cache_clear();

  // Clear bundle display settings.
  variable_del('field_bundle_settings_' . $entity_type . '__' . $bundle);
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}

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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();
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  foreach (config_get_storage_names_with_prefix('field.field.') as $name) {
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    $field = Drupal::config($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();
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  $field_types = Drupal::service('plugin.manager.entity.field.field_type')->getDefinitions();
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  // Set fields with missing field type modules to inactive.
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  foreach ($fields as $uuid => &$field) {
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    // Associate field types.
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    if (isset($field_types[$field['type']]) && ($field['module'] != $field_types[$field['type']]['provider'] || !$field['active'])) {
      $field['module'] = $field_types[$field['type']]['provider'];
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      $field['active'] = TRUE;
      $changed[$uuid] = $field;
    }
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    if (!isset($modules[$field['module']]) && $field['active']) {
      $field['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'])
        ->save();
    }
  }
  $state->set('field.field.deleted', $deleted_fields);

  field_cache_clear();
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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
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    // definition in hook_entity_info_alter() specify they should use custom
    // settings by default.
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    $view_modes = entity_get_view_modes($entity_type);
    foreach ($view_modes as $view_mode => $view_mode_info) {
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      if (!isset($settings[$view_mode]['status']) && $view_mode_info['status']) {
        $settings[$view_mode]['status'] = TRUE;
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      }
    }
    $cache[$entity_type][$bundle] = $settings;
  }

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

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/**
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 * Clears the field info and field data caches.
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 */
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function field_cache_clear() {
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  cache('field')->deleteAll();
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  field_info_cache_clear();
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}

/**
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 * Filters an HTML string to prevent cross-site-scripting (XSS) vulnerabilities.
 *
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 * Like filter_xss_admin(), but with a shorter list of allowed tags.
 *
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 * 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 $string is not valid
 *   UTF-8.
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 */
function field_filter_xss($string) {
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  return _filter_htmlcorrector(filter_xss($string, _field_filter_xss_allowed_tags()));
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}

/**
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 * 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');
}

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

/**
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 * Returns a renderable array for a single field value.
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 *
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 * @param \Drupal\Core\Entity\EntityInterface $entity
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 *   The entity containing the field to display. Must at least contain the ID
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 *   key and the field data to display.
 * @param $field_name
 *   The name of the field to display.
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 * @param $item
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 *   The field value to display, as found in
 *   $entity->field_name[$langcode][$delta].
 * @param $display
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 *   Can be either the name of a view mode, or an array of display settings. See
 *   field_view_field() for more information.
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 * @param $langcode
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 *   (Optional) The language of the value in $item. If not provided, the current
 *   language will be assumed.
 *
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 * @return
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 *   A renderable array for the field value.
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 */
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function field_view_value(EntityInterface $entity, $field_name, $item, $display = array(), $langcode = NULL) {
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  $output = array();
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  // Ensure we are working with a BC mode entity.
  $entity = $entity->getBCEntity();

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  if ($field = field_info_field($entity->entityType(), $field_name)) {
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    // Determine the langcode that will be used by language fallback.
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    $langcode = field_language($entity, $field_name, $langcode);
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    // 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);
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    $elements = field_view_field($clone, $field_name, $display, $langcode);
617

618 619 620 621
    // Extract the part of the render array we need.
    $output = isset($elements[0]) ? $elements[0] : array();
    if (isset($elements['#access'])) {
      $output['#access'] = $elements['#access'];
622 623
    }
  }
624 625

  return $output;
626 627 628
}

/**
629
 * Returns a renderable array for the value of a single field in an entity.
630
 *
631
 * The resulting output is a fully themed field with label and multiple values.
632
 *
633 634
 * This function can be used by third-party modules that need to output an
 * isolated field.
635
 * - Do not use inside node (or any other entity) templates; use
636
 *   render($content[FIELD_NAME]) instead.
637
 * - Do not use to display all fields in an entity; use
638
 *   field_attach_prepare_view() and field_attach_view() instead.
639 640
 * - The field_view_value() function can be used to output a single formatted
 *   field value, without label or wrapping field markup.
641
 *
642 643 644
 * The function takes care of invoking the prepare_view steps. It also respects
 * field access permissions.
 *
645 646
 * @param \Drupal\Core\Entity\EntityInterface $entity
 *   The entity containing the field to display.
647 648
 * @param $field_name
 *   The name of the field to display.
649
 * @param $display_options
650
 *   Can be either:
651 652
 *   - The name of a view mode. The field will be displayed according to the
 *     display settings specified for this view mode in the $instance
653 654 655
 *     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.
656
 *   - An array of display options. The following key/value pairs are allowed:
657 658 659 660
 *     - 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
661 662
 *       'default_formatter' for the field type. The default formatter will also
 *       be used if the requested formatter is not available.
663
 *     - settings: (array) Settings specific to the formatter. Defaults to the
664
 *       formatter's default settings.
665 666 667
 *     - weight: (float) The weight to assign to the renderable element.
 *       Defaults to 0.
 * @param $langcode
668 669
 *   (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
670
 *   available for the given language code. If no language code is provided the
671
 *   current language will be used.
672
 *
673
 * @return
674
 *   A renderable array for the field value.
675 676
 *
 * @see field_view_value()
677
 */
678
function field_view_field(EntityInterface $entity, $field_name, $display_options = array(), $langcode = NULL) {
679
  $output = array();
680
  $bundle = $entity->bundle();
681
  $entity_type = $entity->entityType();
682

683
  // Return nothing if the field doesn't exist.
684
  $instance = field_info_instance($entity_type, $field_name, $bundle);
685 686 687 688 689 690 691
  if (!$instance) {
    return $output;
  }

  // Get the formatter object.
  if (is_string($display_options)) {
    $view_mode = $display_options;
692
    $formatter = entity_get_render_display($entity, $view_mode)->getRenderer($field_name);
693 694 695 696 697
  }
  else {
    $view_mode = '_custom';
    // hook_field_attach_display_alter() needs to receive the 'prepared'
    // $display_options, so we cannot let preparation happen internally.
698
    $field = field_info_field($entity_type, $field_name);
699 700 701
    $formatter_manager = drupal_container()->get('plugin.manager.field.formatter');
    $display_options = $formatter_manager->prepareConfiguration($field['type'], $display_options);
    $formatter = $formatter_manager->getInstance(array(
702
      'field_definition' => $instance,
703 704 705 706 707 708 709
      'view_mode' => $view_mode,
      'prepare' => FALSE,
      'configuration' => $display_options,
    ));
  }

  if ($formatter) {
710
    $display_langcode = field_language($entity, $field_name, $langcode);
711

712
    // Invoke the formatter's prepareView() and view() methods.
713
    $items = $entity->getNGEntity()->getTranslation($display_langcode)->get($field_name);
714
    $id = $entity->id();
715 716
    $formatter->prepareView(array($id => $entity), $display_langcode, array($id => $items));
    $result = $formatter->view($entity, $display_langcode, $items);
717

718 719 720 721 722 723
    // 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,
724
      'langcode' => $display_langcode,
725 726
    );
    drupal_alter('field_attach_view', $result, $context);
727

728 729
    if (isset($result[$field_name])) {
      $output = $result[$field_name];
730
    }
731
  }
732

733 734 735 736
  return $output;
}

/**
737
 * Determines whether the user has access to a given field.
738
 *
739
 * @param string $op
740
 *   The operation to be performed. Possible values:
741 742
 *   - edit
 *   - view
743 744
 * @param \Drupal\field\FieldInterface $field
 *   The field on which the operation is to be performed.
745 746
 * @param $entity_type
 *   The type of $entity; for example, 'node' or 'user'.
747
 * @param $entity
748
 *   (optional) The entity for the operation.
749 750
 * @param $account
 *   (optional) The account to check, if not given use currently logged in user.
751
 *
752
 * @return
753
 *   TRUE if the operation is allowed; FALSE if the operation is denied.
754
 */
755
function field_access($op, FieldInterface $field, $entity_type, $entity = NULL, $account = NULL) {
756 757
  global $user;

758
  if (!isset($account)) {
759 760 761
    $account = $user;
  }

762
  foreach (Drupal::moduleHandler()->getImplementations('field_access') as $module) {
763
    $function = $module . '_field_access';
764
    $access = $function($op, $field, $entity_type, $entity, $account);
765
    if ($access === FALSE) {
766 767 768 769 770 771
      return FALSE;
    }
  }
  return TRUE;
}

772
/**
773
 * Extracts the bundle name from a bundle object.
774
 *
775
 * @param $entity_type
776
 *   The type of $entity; e.g., 'node' or 'user'.
777
 * @param $bundle
778
 *   The bundle object (or string if bundles for this entity type do not exist
779
 *   as standalone objects).
780
 *
781 782 783
 * @return
 *   The bundle name.
 */
784
function field_extract_bundle($entity_type, $bundle) {
785 786 787 788
  if (is_string($bundle)) {
    return $bundle;
  }

789
  $info = entity_get_info($entity_type);
790 791
  if (is_object($bundle) && isset($info['bundle_keys']['bundle']) && isset($bundle->{$info['bundle_keys']['bundle']})) {
    return $bundle->{$info['bundle_keys']['bundle']};
792 793 794
  }
}

795 796 797 798 799
/**
 * Implements hook_page_build().
 */
function field_page_build(&$page) {
  $path = drupal_get_path('module', 'field');
800
  $page['#attached']['css'][$path . '/css/field.module.css'] = array('every_page' => TRUE);
801 802
}

803
/**
804
 * Prepares variables for field templates.
805
 *
806 807 808 809 810 811 812 813 814
 * Default template: field.html.twig.
 *
 * @param array $variables
 *   An associative array containing:
 *   - element: A render element representing the field.
 *   - attributes: A string containing the attributes for the wrapping div.
 *   - title_attributes: A string containing the attributes for the title.
 *   - content_attributes: A string containing the attributes for the content's
 *     div.
815
 */
816
function template_preprocess_field(&$variables, $hook) {
817 818
  $element = $variables['element'];

819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842
  // 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().
843
  $variables['entity_type_css'] = strtr($element['#entity_type'], '_', '-');
844 845
  $variables['field_name_css'] = strtr($element['#field_name'], '_', '-');
  $variables['field_type_css'] = strtr($element['#field_type'], '_', '-');
846
  $variables['attributes']['class'] = array(
847
    'field',
848
    'field-' . $variables['entity_type_css'] . '--' . $variables['field_name_css'],
849 850 851
    'field-name-' . $variables['field_name_css'],
    'field-type-' . $variables['field_type_css'],
    'field-label-' . $element['#label_display'],
852
  );
853
  // Add a "clearfix" class to the wrapper since we float the label and the
854
  // field items in field.module.css if the label is inline.
855
  if ($element['#label_display'] == 'inline') {
856
    $variables['attributes']['class'][] = 'clearfix';
857
  }
858

859 860
  // Add specific suggestions that can override the default implementation.
  $variables['theme_hook_suggestions'] = array(
861
    'field__' . $element['#field_type'],
862
    'field__' . $element['#field_name'],
863 864 865
    'field__' . $element['#entity_type'] . '__' . $element['#bundle'],
    'field__' . $element['#entity_type'] . '__' . $element['#field_name'],
    'field__' . $element['#entity_type'] . '__' . $element['#field_name'] . '__' . $element['#bundle'],
866
  );
867

868 869
  static $default_attributes;
  if (!isset($default_attributes)) {
870
    $default_attributes = new Attribute;
871
  }
872 873 874 875 876 877 878
  // The default theme implementation for fields is a function.
  // template_preprocess() (which initializes the attributes, title_attributes,
  // and content_attributes arrays) does not run for theme function
  // implementations. Additionally, Attribute objects for the three variables
  // below only get instantiated for template file implementations, and we need
  // Attribute objects for printing in both theme functions and template files.
  // For best performance, we only instantiate Attribute objects when needed.
879 880 881
  $variables['attributes'] = isset($variables['attributes']) ? new Attribute($variables['attributes']) : clone $default_attributes;
  $variables['title_attributes'] = isset($variables['title_attributes']) ? new Attribute($variables['title_attributes']) : clone($default_attributes);
  $variables['content_attributes'] = isset($variables['content_attributes']) ? new Attribute($variables['content_attributes']) : clone($default_attributes);
882
  foreach ($variables['items'] as $delta => $item) {
883
    $variables['item_attributes'][$delta] = isset($variables['item_attributes'][$delta]) ? new Attribute($variables['item_attributes'][$delta]) : clone($default_attributes);
884 885
  }
}
886

887
/**
888
 * @} End of "defgroup field".
889
 */
890 891

/**
892
 * Returns HTML for a field.
893 894 895 896 897 898 899 900 901 902 903 904 905 906
 *
 * This is the default theme implementation to display the value of a field.
 * Theme developers who are comfortable with overriding theme functions may do
 * so in order to customize this markup. This function can be overridden with
 * varying levels of specificity. For example, for a field named 'body'
 * displayed on the 'article' content type, any of the following functions will
 * override this default implementation. The first of these functions that
 * exists is used:
 * - THEMENAME_field__body__article()
 * - THEMENAME_field__article()
 * - THEMENAME_field__body()
 * - THEMENAME_field()
 *
 * Theme developers who prefer to customize templates instead of overriding
907 908
 * functions may copy the "field.html.twig" from the "modules/field/theme"
 * folder of the Drupal installation to somewhere within the theme's folder and
909
 * customize it, just like customizing other Drupal templates such as
910
 * page.html.twig or node.html.twig. However, it takes longer for the server to
911 912
 * process templates than to call a function, so for websites with many fields
 * displayed on a page, this can result in a noticeable slowdown of the website.
913
 * For these websites, developers are discouraged from placing a field.html.twig
914 915 916 917
 * file into the theme's folder, but may customize templates for specific
 * fields. For example, for a field named 'body' displayed on the 'article'
 * content type, any of the following templates will override this default
 * implementation. The first of these templates that exists is used:
918 919 920 921
 * - field--body--article.html.twig
 * - field--article.html.twig
 * - field--body.html.twig
 * - field.html.twig
922
 * So, if the body field on the article content type needs customization, a
923
 * field--body--article.html.twig file can be added within the theme's folder.
924
 * Because it's a template, it will result in slightly more time needed to
925 926
 * display that field, but it will not impact other fields, and therefore, is
 * unlikely to cause a noticeable change in website performance. A very rough
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