field.module 44.4 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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/*
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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.default.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
 *   bulk deletion operations such as field_delete_field() and
 *   field_delete_instance().
 *
 * - @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_data_type_info() to register data types for all field types.
 */
function field_data_type_info() {
  $field_types = field_info_field_types();
  $items = array();

  // Expose data types for all the field type items.
  foreach ($field_types as $type_name => $type_info) {
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    $data_type = isset($type_info['data_type']) ? $type_info['data_type'] : $type_name . '_field';
    $items[$data_type] = array(
      'label' => t('Field !label item', array('!label' => $type_info['label'])),
      'class' => $type_info['field item class'],
      'list class' => !empty($type_info['field class']) ? $type_info['field class'] : '\Drupal\Core\Entity\Field\Type\Field',
    );
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  }
  return $items;
}

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

/**
 * 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();
  $langcode = $langcode ?: $entity->language()->langcode;
  foreach (field_info_instances($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();
  $field_types = field_info_field_types();

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

    foreach ($instances as $field_name => $instance) {
      $field = field_info_field($field_name);

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      // @todo: Allow for adding field type settings.
      $definition = array(
        'label' => t('Field !name', array('!name' => $field_name)),
        'type' => isset($field_types[$field['type']]['data_type']) ? $field_types[$field['type']]['data_type'] :  $field['type'] . '_field',
        'configurable' => TRUE,
        'translatable' => !empty($field['translatable'])
      );
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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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/**
 * 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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 * Filters out empty field values.
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 *
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 * @param $field
 *   The field definition.
 * @param $items
 *   The field values to filter.
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 *
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 * @return
 *   The array of items without empty field values. The function also renumbers
 *   the array keys to ensure sequential deltas.
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 */
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function _field_filter_items($field, $items) {
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  $function = $field['module'] . '_field_is_empty';
  foreach ((array) $items as $delta => $item) {
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    // Explicitly break if the function is undefined.
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    if ($function($item, $field)) {
      unset($items[$delta]);
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    }
  }
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  return array_values($items);
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}

/**
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 * Sorts items in a field according to user drag-and-drop reordering.
 *
 * @param $field
 *   The field definition.
 * @param $items
 *   The field values to sort.
 *
 * @return
 *   The sorted array of field items.
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 */
function _field_sort_items($field, $items) {
  if (($field['cardinality'] > 1 || $field['cardinality'] == FIELD_CARDINALITY_UNLIMITED) && isset($items[0]['_weight'])) {
    usort($items, '_field_sort_items_helper');
    foreach ($items as $delta => $item) {
      if (is_array($items[$delta])) {
        unset($items[$delta]['_weight']);
      }
    }
  }
  return $items;
}

/**
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 * Callback for usort() within _field_sort_items().
 *
 * Copied form element_sort(), which acts on #weight keys.
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 */
function _field_sort_items_helper($a, $b) {
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  $a_weight = (is_array($a) ? $a['_weight'] : 0);
  $b_weight = (is_array($b) ? $b['_weight'] : 0);
  return $a_weight - $b_weight;
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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();
605 606
  }
  else {
607
    $settings = variable_get('field_bundle_settings_' . $entity_type . '__' . $bundle, array());
608 609
    $settings += array(
      'view_modes' => array(),
610
    );
611 612 613 614 615 616 617 618 619 620 621 622 623 624 625

    return $settings;
  }
}

/**
 * Returns view mode settings in a given bundle.
 *
 * @param $entity_type
 *   The type of entity; e.g. 'node' or 'user'.
 * @param $bundle
 *   The bundle name to return view mode settings for.
 *
 * @return
 *   An array keyed by view mode, with the following key/value pairs:
626 627 628
 *   - status: Boolean specifying whether the view mode uses a dedicated set of
 *     display options (TRUE), or the 'default' options (FALSE). Defaults to
 *     FALSE.
629 630 631 632 633 634 635 636
 */
function field_view_mode_settings($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
637 638
    // definition in hook_entity_info_alter() specify they should use custom
    // settings by default.
639 640
    $view_modes = entity_get_view_modes($entity_type);
    foreach ($view_modes as $view_mode => $view_mode_info) {
641 642
      if (!isset($settings[$view_mode]['status']) && $view_mode_info['status']) {
        $settings[$view_mode]['status'] = TRUE;
643 644 645 646 647 648 649 650
      }
    }
    $cache[$entity_type][$bundle] = $settings;
  }

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

651
/**
652
 * Clears the field info and field data caches.
653
 */
654
function field_cache_clear() {
655
  cache('field')->deleteAll();
656
  field_info_cache_clear();
657 658 659
}

/**
660 661
 * Filters an HTML string to prevent cross-site-scripting (XSS) vulnerabilities.
 *
662 663
 * Like filter_xss_admin(), but with a shorter list of allowed tags.
 *
664 665 666 667 668 669 670 671 672 673
 * 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 $string is not valid
 *   UTF-8.
674 675
 */
function field_filter_xss($string) {
676
  return _filter_htmlcorrector(filter_xss($string, _field_filter_xss_allowed_tags()));
677 678 679
}

/**
680
 * Returns a list of tags allowed by field_filter_xss().
681 682 683 684 685 686
 */
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');
}

/**
687
 * Returns a human-readable list of allowed tags for display in help texts.
688 689 690 691 692 693
 */
function _field_filter_xss_display_allowed_tags() {
  return '<' . implode('> <', _field_filter_xss_allowed_tags()) . '>';
}

/**
694
 * Returns a renderable array for a single field value.
695
 *
696
 * @param \Drupal\Core\Entity\EntityInterface $entity
697
 *   The entity containing the field to display. Must at least contain the ID
698 699 700
 *   key and the field data to display.
 * @param $field_name
 *   The name of the field to display.
701
 * @param $item
702 703 704
 *   The field value to display, as found in
 *   $entity->field_name[$langcode][$delta].
 * @param $display
705 706
 *   Can be either the name of a view mode, or an array of display settings. See
 *   field_view_field() for more information.
707
 * @param $langcode
708 709 710
 *   (Optional) The language of the value in $item. If not provided, the current
 *   language will be assumed.
 *
711
 * @return
712
 *   A renderable array for the field value.
713
 */
714
function field_view_value(EntityInterface $entity, $field_name, $item, $display = array(), $langcode = NULL) {
715
  $output = array();
716

717 718
  if ($field = field_info_field($field_name)) {
    // Determine the langcode that will be used by language fallback.
719
    $langcode = field_language($entity, $field_name, $langcode);
720

721 722 723 724
    // 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);
725
    $elements = field_view_field($clone, $field_name, $display, $langcode);
726

727 728 729 730
    // Extract the part of the render array we need.
    $output = isset($elements[0]) ? $elements[0] : array();
    if (isset($elements['#access'])) {
      $output['#access'] = $elements['#access'];
731 732
    }
  }
733 734

  return $output;
735 736 737
}

/**
738
 * Returns a renderable array for the value of a single field in an entity.
739
 *
740
 * The resulting output is a fully themed field with label and multiple values.
741
 *
742 743 744 745
 * 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.
746
 * - Do not use to display all fields in an entity, use
747
 *   field_attach_prepare_view() and field_attach_view() instead.
748 749
 * - The field_view_value() function can be used to output a single formatted
 *   field value, without label or wrapping field markup.
750
 *
751 752 753
 * The function takes care of invoking the prepare_view steps. It also respects
 * field access permissions.
 *
754 755
 * @param \Drupal\Core\Entity\EntityInterface $entity
 *   The entity containing the field to display.
756 757
 * @param $field_name
 *   The name of the field to display.
758
 * @param $display_options
759
 *   Can be either:
760 761
 *   - The name of a view mode. The field will be displayed according to the
 *     display settings specified for this view mode in the $instance
762 763 764
 *     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.
765
 *   - An array of display options. The following key/value pairs are allowed:
766 767 768 769
 *     - 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
770 771 772
 *       'default_formatter' for the field type, specified in hook_field_info().
 *       The default formatter will also be used if the requested formatter is
 *       not available.
773
 *     - settings: (array) Settings specific to the formatter. Defaults to the
774
 *       formatter's default settings, specified in hook_field_formatter_info().
775 776 777
 *     - weight: (float) The weight to assign to the renderable element.
 *       Defaults to 0.
 * @param $langcode
778 779
 *   (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
780
 *   available for the given language code. If no language code is provided the
781
 *   current language will be used.
782
 *
783
 * @return
784
 *   A renderable array for the field value.
785 786
 *
 * @see field_view_value()
787
 */
788
function field_view_field(EntityInterface $entity, $field_name, $display_options = array(), $langcode = NULL) {
789
  $output = array();
790
  $bundle = $entity->bundle();
791

792
  // Return nothing if the field doesn't exist.
793
  $instance = field_info_instance($entity->entityType(), $field_name, $bundle);
794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818
  if (!$instance) {
    return $output;
  }

  // Get the formatter object.
  if (is_string($display_options)) {
    $view_mode = $display_options;
    $formatter = entity_get_render_display($entity, $view_mode)->getFormatter($field_name);
  }
  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(
      'instance' => $instance,
      'view_mode' => $view_mode,
      'prepare' => FALSE,
      'configuration' => $display_options,
    ));
  }

  if ($formatter) {
819
    $display_langcode = field_language($entity, $field_name, $langcode);
820
    $items = array();
821 822
    // Ensure the BC entity is used.
    $entity = $entity->getBCEntity();
823 824 825
    if (isset($entity->{$field_name}[$display_langcode])) {
      $items = $entity->{$field_name}[$display_langcode];
    }
826 827 828 829 830 831 832 833

    // Invoke prepare_view steps if needed.
    if (empty($entity->_field_view_prepared)) {
      $id = $entity->id();

      // First let the field types do their preparation.
      $options = array('field_name' => $field_name, 'langcode' => $display_langcode);
      $null = NULL;
834
      _field_invoke_multiple('prepare_view', $entity->entityType(), array($id => $entity), $null, $null, $options);
835 836

      // Then let the formatter do its own specific massaging.
837 838 839 840
      $items_multi = array($id => array());
      if (isset($entity->{$field_name}[$display_langcode])) {
        $items_multi[$id] = $entity->{$field_name}[$display_langcode];
      }
841 842
      $formatter->prepareView(array($id => $entity), $display_langcode, $items_multi);
      $items = $items_multi[$id];
843 844
    }

845 846
    // Build the renderable array.
    $result = $formatter->view($entity, $display_langcode, $items);
847

848 849 850 851 852 853
    // 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,
854
      'langcode' => $display_langcode,
855 856
    );
    drupal_alter('field_attach_view', $result, $context);
857

858 859
    if (isset($result[$field_name])) {
      $output = $result[$field_name];
860
    }
861
  }
862

863 864 865
  return $output;
}

866 867 868
/**
 * Returns the field items in the language they currently would be displayed.
 *
869
 * @param \Drupal\Core\Entity\EntityInterface $entity
870 871 872 873 874 875 876 877
 *   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
878
 *   An array with available field items keyed by delta.
879
 */
880
function field_get_items(EntityInterface $entity, $field_name, $langcode = NULL) {
881
  $entity = $entity->getBCEntity();
882
  $langcode = field_language($entity, $field_name, $langcode);
883
  return isset($entity->{$field_name}[$langcode]) ? $entity->{$field_name}[$langcode] : array();
884 885
}

886
/**
887
 * Determines whether a field has any data.
888 889 890
 *
 * @param $field
 *   A field structure.
891
 *
892
 * @return
893
 *   TRUE if the field has data for any entity; FALSE otherwise.
894 895
 */
function field_has_data($field) {
896
  $columns = array_keys($field['columns']);
897
  $factory = Drupal::service('entity.query');
898
  foreach ($field['bundles'] as $entity_type => $bundle) {
899 900 901 902 903
    // Entity Query throws an exception if there is no base table.
    $entity_info = entity_get_info($entity_type);
    if (!isset($entity_info['base_table'])) {
      continue;
    }
904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920
    $query = $factory->get($entity_type);
    $group = $query->orConditionGroup();
    foreach ($columns as $column) {
      $group->exists($field['field_name'] . '.' . $column);
    }
    $result = $query
      ->condition($group)
      ->count()
      ->accessCheck(FALSE)
      ->range(0, 1)
      ->execute();
    if ($result) {
      return TRUE;
    }
  }

  return FALSE;
921 922
}

923
/**
924
 * Determines whether the user has access to a given field.
925
 *
926
 * @param string $op
927
 *   The operation to be performed. Possible values:
928 929
 *   - edit
 *   - view
930 931 932
 * @param array $field
 *   The full field structure array for the field on which the operation is to
 *   be performed. See field_info_field().
933 934
 * @param $entity_type
 *   The type of $entity; for example, 'node' or 'user'.
935
 * @param $entity
936
 *   (optional) The entity for the operation.
937 938
 * @param $account
 *   (optional) The account to check, if not given use currently logged in user.
939
 *
940
 * @return
941
 *   TRUE if the operation is allowed; FALSE if the operation is denied.
942
 */
943
function field_access($op, $field, $entity_type, $entity = NULL, $account = NULL) {
944 945
  global $user;

946
  if (!isset($account)) {
947 948 949
    $account = $user;
  }

950 951
  foreach (module_implements('field_access') as $module) {
    $function = $module . '_field_access';
952
    $access = $function($op, $field, $entity_type, $entity, $account);
953
    if ($access === FALSE) {
954 955 956 957 958 959
      return FALSE;
    }
  }
  return TRUE;
}

960
/**
961
 * Extracts the bundle name from a bundle object.
962
 *
963
 * @param $entity_type
964
 *   The type of $entity; e.g., 'node' or 'user'.
965
 * @param $bundle
966
 *   The bundle object (or string if bundles for this entity type do not exist
967
 *   as standalone objects).
968
 *
969 970 971
 * @return
 *   The bundle name.
 */
972
function field_extract_bundle($entity_type, $bundle) {
973 974 975 976
  if (is_string($bundle)) {
    return $bundle;
  }

977
  $info = entity_get_info($entity_type);
978 979
  if (is_object($bundle) && isset($info['bundle_keys']['bundle']) && isset($bundle->{$info['bundle_keys']['bundle']})) {
    return $bundle->{$info['bundle_keys']['bundle']};
980 981 982
  }
}

983 984 985 986 987
/**
 * Implements hook_page_build().
 */
function field_page_build(&$page) {
  $path = drupal_get_path('module', 'field');
988
  $page['#attached']['css'][$path . '/css/field.module.css'] = array('every_page' => TRUE);
989 990
}

991
/**