field_ui.admin.inc

<?php

/**
 * @file
 * Administrative interface for custom field type creation.
 */

/**
 * Menu callback; lists all defined fields for quick reference.
 */
function field_ui_fields_list() {
  $instances = field_info_instances();
  $field_types = field_info_field_types();
  $bundles = field_info_bundles();

  $modules = system_rebuild_module_data();

  $header = array(t('Field name'), t('Field type'), t('Used in'));
  $rows = array();
  foreach ($instances as $entity_type => $type_bundles) {
    foreach ($type_bundles as $bundle => $bundle_instances) {
      foreach ($bundle_instances as $field_name => $instance) {
        $field = field_info_field($field_name);

        // Initialize the row if we encounter the field for the first time.
        if (!isset($rows[$field_name])) {
          $rows[$field_name]['class'] = $field['locked'] ? array('menu-disabled') : array('');
          $rows[$field_name]['data'][0] = $field['locked'] ? t('@field_name (Locked)', array('@field_name' => $field_name)) : $field_name;
          $module_name = $field_types[$field['type']]['module'];
          $rows[$field_name]['data'][1] = $field_types[$field['type']]['label'] . ' ' . t('(module: !module)', array('!module' => $modules[$module_name]->info['name']));
        }

        // Add the current instance.
        $admin_path = _field_ui_bundle_admin_path($entity_type, $bundle);
        $rows[$field_name]['data'][2][] = $admin_path ? l($bundles[$entity_type][$bundle]['label'], $admin_path . '/fields') : $bundles[$entity_type][$bundle]['label'];
      }
    }
  }
  foreach ($rows as $field_name => $cell) {
    $rows[$field_name]['data'][2] = implode(', ', $cell['data'][2]);
  }
  if (empty($rows)) {
    $output = t('No fields have been defined yet.');
  }
  else {
    // Sort rows by field name.
    ksort($rows);
    $output = theme('table', array('header' => $header, 'rows' => $rows));
  }
  return $output;
}

/**
 * Helper function to display a message about inactive fields.
 */
function field_ui_inactive_message($entity_type, $bundle) {
  $inactive_instances = field_ui_inactive_instances($entity_type, $bundle);
  if (!empty($inactive_instances)) {
    $field_types = field_info_field_types();
    $widget_types = field_info_widget_types();

    foreach ($inactive_instances as $field_name => $instance) {
      $list[] = t('%field (@field_name) field requires the %widget_type widget provided by %widget_module module', array(
      '%field' => $instance['label'],
      '@field_name' => $instance['field_name'],
      '%widget_type' => isset($widget_types[$instance['widget']['type']]) ? $widget_types[$instance['widget']['type']]['label'] : $instance['widget']['type'],
      '%widget_module' => $instance['widget']['module'],
      ));
    }
    drupal_set_message(t('Inactive fields are not shown unless their providing modules are enabled. The following fields are not enabled: !list', array('!list' => theme('item_list', array('items' => $list)))), 'error');
  }
}

/**
 * Helper function: determines the rendering order of a tree array.
 *
 * This is intended as a callback for array_reduce().
 */
function _field_ui_reduce_order($array, $a) {
  $array = !isset($array) ? array() : $array;
  if ($a['name']) {
    $array[] = $a['name'];
  }
  if (!empty($a['children'])) {
    uasort($a['children'], 'drupal_sort_weight');
    $array = array_merge($array, array_reduce($a['children'], '_field_ui_reduce_order'));
  }
  return $array;
}

/**
 * Returns the region to which a row in the 'Manage fields' screen belongs.
 *
 * This function is used as a #row_callback in field_ui_field_overview_form(),
 * and is called during field_ui_table_pre_render().
 */
function field_ui_field_overview_row_region($row) {
  switch ($row['#row_type']) {
    case 'field':
    case 'extra_field':
      return 'main';
    case 'add_new_field':
      // If no input in 'label', assume the row has not been dragged out of the
      // 'add new' section.
      return (!empty($row['label']['#value']) ? 'main' : 'add_new');
  }
}

/**
 * Returns the region to which a row in the 'Manage display' screen belongs.
 *
 * This function is used as a #row_callback in field_ui_field_overview_form(),
 * and is called during field_ui_table_pre_render().
 */
function field_ui_display_overview_row_region($row) {
  switch ($row['#row_type']) {
    case 'field':
    case 'extra_field':
      return ($row['format']['type']['#value'] == 'hidden' ? 'hidden' : 'visible');
  }
}

/**
 * Pre-render callback for field_ui_table elements.
 */
function field_ui_table_pre_render($elements) {
  $js_settings = array();

  // For each region, build the tree structure from the weight and parenting
  // data contained in the flat form structure, to determine row order and
  // indentation.
  $regions = $elements['#regions'];
  $tree = array('' => array('name' => '', 'children' => array()));
  $trees = array_fill_keys(array_keys($regions), $tree);

  $parents = array();
  $list = drupal_map_assoc(element_children($elements));

  // Iterate on rows until we can build a known tree path for all of them.
  while ($list) {
    foreach ($list as $name) {
      $row = &$elements[$name];
      $parent = $row['parent_wrapper']['parent']['#value'];
      // Proceed if parent is known.
      if (empty($parent) || isset($parents[$parent])) {
        // Grab parent, and remove the row from the next iteration.
        $parents[$name] = $parent ? array_merge($parents[$parent], array($parent)) : array();
        unset($list[$name]);

        // Determine the region for the row.
        $function = $row['#region_callback'];
        $region_name = $function($row);

        // Add the element in the tree.
        $target = &$trees[$region_name][''];
        foreach ($parents[$name] as $key) {
          $target = &$target['children'][$key];
        }
        $target['children'][$name] = array('name' => $name, 'weight' => $row['weight']['#value']);

        // Add tabledrag indentation to the first row cell.
        if ($depth = count($parents[$name])) {
          $cell = current(element_children($row));
          $row[$cell]['#prefix'] = theme('indentation', array('size' => $depth)) . (isset($row[$cell]['#prefix']) ? $row[$cell]['#prefix'] : '');
        }

        // Add row id and associate JS settings.
        $id = drupal_html_class($name);
        $row['#attributes']['id'] = $id;
        if (isset($row['#js_settings'])) {
          $row['#js_settings'] += array(
            'rowHandler' => $row['#row_type'],
            'name' => $name,
            'region' => $region_name,
          );
          $js_settings[$id] = $row['#js_settings'];
        }
      }
    }
  }
  // Determine rendering order from the tree structure.
  foreach ($regions as $region_name => $region) {
    $elements['#regions'][$region_name]['rows_order'] = array_reduce($trees[$region_name], '_field_ui_reduce_order');
  }

  $elements['#attached']['js'][] = array(
    'type' => 'setting',
    'data' => array('fieldUIRowsData' => $js_settings),
  );

  return $elements;
}

/**
 * Returns HTML for Field UI overview tables.
 *
 * @param $variables
 *   An associative array containing:
 *   - elements: An associative array containing a Form API structure to be
 *     rendered as a table.
 *
 * @ingroup themeable
 */
function theme_field_ui_table($variables) {
  $elements = $variables['elements'];
  $table = array();
  $js_settings = array();

  // Add table headers and attributes.
  foreach (array('header', 'attributes') as $key) {
    if (isset($elements["#$key"])) {
      $table[$key] = $elements["#$key"];
    }
  }

  // Determine the colspan to use for region rows, by checking the number of
  // columns in the headers.
  $colums_count = 0;
  foreach ($table['header'] as $header) {
    $colums_count += (is_array($header) && isset($header['colspan']) ? $header['colspan'] : 1);
  }

  // Render rows, region by region.
  foreach ($elements['#regions'] as $region_name => $region) {
    $region_name_class = drupal_html_class($region_name);

    // Add region rows.
    if (isset($region['title'])) {
      $table['rows'][] = array(
        'class' => array('region-title', 'region-' . $region_name_class . '-title'),
        'no_striping' => TRUE,
        'data' => array(
          array('data' => $region['title'], 'colspan' => $colums_count),
        ),
      );
    }
    if (isset($region['message'])) {
      $class = (empty($region['rows_order']) ? 'region-empty' : 'region-populated');
      $table['rows'][] = array(
        'class' => array('region-message', 'region-' . $region_name_class . '-message', $class),
        'no_striping' => TRUE,
        'data' => array(
          array('data' => $region['message'], 'colspan' => $colums_count),
        ),
      );
    }

    // Add form rows, in the order determined at pre-render time.
    foreach ($region['rows_order'] as $name) {
      $element = $elements[$name];

      $row = array('data' => array());
      if (isset($element['#attributes'])) {
        $row += $element['#attributes'];
      }

      foreach (element_children($element) as $cell_key) {
        $cell = array('data' => drupal_render($element[$cell_key]));
        if (isset($element[$cell_key]['#cell_attributes'])) {
          $cell += $element[$cell_key]['#cell_attributes'];
        }
        $row['data'][] = $cell;
      }
      $table['rows'][] = $row;
    }
  }

  return theme('table', $table);
}

/**
 * Menu callback; listing of fields for a bundle.
 *
 * Allows fields and pseudo-fields to be re-ordered.
 */
function field_ui_field_overview_form($form, &$form_state, $entity_type, $bundle) {
  $bundle = field_extract_bundle($entity_type, $bundle);

  field_ui_inactive_message($entity_type, $bundle);
  $admin_path = _field_ui_bundle_admin_path($entity_type, $bundle);

  // When displaying the form, make sure the list of fields is up-to-date.
  if (empty($form_state['post'])) {
    field_info_cache_clear();
  }

  // Gather bundle information.
  $instances = field_info_instances($entity_type, $bundle);
  $field_types = field_info_field_types();
  $widget_types = field_info_widget_types();

  $extra_fields = field_info_extra_fields($entity_type, $bundle, 'form');

  $form += array(
    '#entity_type' => $entity_type,
    '#bundle' => $bundle,
    '#fields' => array_keys($instances),
    '#extra' => array_keys($extra_fields),
  );

  $table = array(
    '#type' => 'field_ui_table',
    '#tree' => TRUE,
    '#header' => array(
      t('Label'),
      t('Weight'),
      t('Parent'),
      t('Name'),
      t('Field'),
      t('Widget'),
      array('data' => t('Operations'), 'colspan' => 2),
    ),
    '#parent_options' => array(),
    '#regions' => array(
      'main' => array('message' => t('No fields are present yet.')),
      'add_new' => array('title' => '&nbsp;'),
    ),
    '#attributes' => array(
      'class' => array('field-ui-overview'),
      'id' => 'field-overview',
    ),
  );

  // Fields.
  foreach ($instances as $name => $instance) {
    $field = field_info_field($instance['field_name']);
    $admin_field_path = $admin_path . '/fields/' . $instance['field_name'];
    $table[$name] = array(
      '#attributes' => array('class' => array('draggable', 'tabledrag-leaf')),
      '#row_type' => 'field',
      '#region_callback' => 'field_ui_field_overview_row_region',
      'label' => array(
        '#markup' => check_plain($instance['label']),
      ),
      'weight' => array(
        '#type' => 'textfield',
        '#title' => t('Weight for @title', array('@title' => $instance['label'])),
        '#title_display' => 'invisible',
        '#default_value' => $instance['widget']['weight'],
        '#size' => 3,
        '#attributes' => array('class' => array('field-weight')),
       ),
      'parent_wrapper' => array(
        'parent' => array(
          '#type' => 'select',
          '#title' => t('Parent for @title', array('@title' => $instance['label'])),
          '#title_display' => 'invisible',
          '#options' => $table['#parent_options'],
          '#empty_value' => '',
          '#attributes' => array('class' => array('field-parent')),
          '#parents' => array('fields', $name, 'parent'),
        ),
        'hidden_name' => array(
          '#type' => 'hidden',
          '#default_value' => $name,
          '#attributes' => array('class' => array('field-name')),
        ),
      ),
      'field_name' => array(
        '#markup' => $instance['field_name'],
      ),
      'type' => array(
        '#type' => 'link',
        '#title' => t($field_types[$field['type']]['label']),
        '#href' => $admin_field_path . '/field-settings',
        '#options' => array('attributes' => array('title' => t('Edit field settings.'))),
      ),
      'widget_type' => array(
        '#type' => 'link',
        '#title' => t($widget_types[$instance['widget']['type']]['label']),
        '#href' => $admin_field_path . '/widget-type',
        '#options' => array('attributes' => array('title' => t('Change widget type.'))),
      ),
      'edit' => array(
        '#type' => 'link',
        '#title' => t('edit'),
        '#href' => $admin_field_path,
        '#options' => array('attributes' => array('title' => t('Edit instance settings.'))),
      ),
      'delete' => array(
        '#type' => 'link',
        '#title' => t('delete'),
        '#href' => $admin_field_path . '/delete',
        '#options' => array('attributes' => array('title' => t('Delete instance.'))),
      ),
    );

    if (!empty($instance['locked'])) {
      $table[$name]['edit'] = array('#value' => t('Locked'));
      $table[$name]['delete'] = array();
      $table[$name]['#attributes']['class'][] = 'menu-disabled';
    }
  }

  // Non-field elements.
  foreach ($extra_fields as $name => $extra_field) {
    $table[$name] = array(
      '#attributes' => array('class' => array('draggable', 'tabledrag-leaf')),
      '#row_type' => 'extra_field',
      '#region_callback' => 'field_ui_field_overview_row_region',
      'label' => array(
        '#markup' => check_plain($extra_field['label']),
      ),
      'weight' => array(
        '#type' => 'textfield',
        '#default_value' => $extra_field['weight'],
        '#size' => 3,
        '#attributes' => array('class' => array('field-weight')),
        '#title_display' => 'invisible',
        '#title' => t('Weight for @title', array('@title' => $extra_field['label'])),
      ),
      'parent_wrapper' => array(
        'parent' => array(
          '#type' => 'select',
          '#title' => t('Parent for @title', array('@title' => $extra_field['label'])),
          '#title_display' => 'invisible',
          '#options' => $table['#parent_options'],
          '#empty_value' => '',
          '#attributes' => array('class' => array('field-parent')),
          '#parents' => array('fields', $name, 'parent'),
        ),
        'hidden_name' => array(
          '#type' => 'hidden',
          '#default_value' => $name,
          '#attributes' => array('class' => array('field-name')),
        ),
      ),
      'field_name' => array(
        '#markup' => $name,
      ),
      'type' => array(
        '#markup' => isset($extra_field['description']) ? $extra_field['description'] : '',
        '#cell_attributes' => array('colspan' => 2),
      ),
      'edit' => array(
        '#markup' => isset($extra_field['edit']) ? $extra_field['edit'] : '',
      ),
      'delete' => array(
        '#markup' => isset($extra_field['delete']) ? $extra_field['delete'] : '',
      ),
    );
  }

  // Additional row: add new field.
  $max_weight = field_info_max_weight($entity_type, $bundle, 'form');
  $field_type_options = field_ui_field_type_options();
  $widget_type_options = field_ui_widget_type_options(NULL, TRUE);
  if ($field_type_options && $widget_type_options) {
    $name = '_add_new_field';
    $table[$name] = array(
      '#attributes' => array('class' => array('draggable', 'tabledrag-leaf', 'add-new')),
      '#row_type' => 'add_new_field',
      '#region_callback' => 'field_ui_field_overview_row_region',
      'label' => array(
        '#type' => 'textfield',
        '#title' => t('New field label'),
        '#title_display' => 'invisible',
        '#size' => 15,
        '#description' => t('Label'),
        '#prefix' => '<div class="label-input"><div class="add-new-placeholder">' . t('Add new field') .'</div>',
        '#suffix' => '</div>',
      ),
      'weight' => array(
        '#type' => 'textfield',
        '#default_value' => $max_weight + 1,
        '#size' => 3,
        '#title_display' => 'invisible',
        '#title' => t('Weight for new field'),
        '#attributes' => array('class' => array('field-weight')),
        '#prefix' => '<div class="add-new-placeholder">&nbsp;</div>',
      ),
      'parent_wrapper' => array(
        'parent' => array(
          '#type' => 'select',
          '#title' => t('Parent for new field'),
          '#title_display' => 'invisible',
          '#options' => $table['#parent_options'],
          '#empty_value' => '',
          '#attributes' => array('class' => array('field-parent')),
          '#prefix' => '<div class="add-new-placeholder">&nbsp;</div>',
          '#parents' => array('fields', $name, 'parent'),
        ),
        'hidden_name' => array(
          '#type' => 'hidden',
          '#default_value' => $name,
          '#attributes' => array('class' => array('field-name')),
        ),
      ),
      'field_name' => array(
        '#type' => 'textfield',
        '#title' => t('New field name'),
        '#title_display' => 'invisible',
        // This field should stay LTR even for RTL languages.
        '#field_prefix' => '<span dir="ltr">field_',
        '#field_suffix' => '</span>&lrm;',
        '#attributes' => array('dir'=>'ltr'),
        '#size' => 10,
        '#description' => t('Field name (a-z, 0-9, _)'),
        '#prefix' => '<div class="add-new-placeholder">&nbsp;</div>',
      ),
      'type' => array(
        '#type' => 'select',
        '#title' => t('Type of new field'),
        '#title_display' => 'invisible',
        '#options' => $field_type_options,
        '#empty_option' => t('- Select a field type -'),
        '#description' => t('Type of data to store.'),
        '#attributes' => array('class' => array('field-type-select')),
        '#prefix' => '<div class="add-new-placeholder">&nbsp;</div>',
      ),
      'widget_type' => array(
        '#type' => 'select',
        '#title' => t('Widget for new field'),
        '#title_display' => 'invisible',
        '#options' => $widget_type_options,
        '#empty_option' => t('- Select a widget -'),
        '#description' => t('Form element to edit the data.'),
        '#attributes' => array('class' => array('widget-type-select')),
        '#cell_attributes' => array('colspan' => 3),
        '#prefix' => '<div class="add-new-placeholder">&nbsp;</div>',
      ),
      'translatable' => array(
        '#type' => 'value',
        '#value' => FALSE,
      ),
    );
  }

  // Additional row: add existing field.
  $existing_field_options = field_ui_existing_field_options($entity_type, $bundle);
  if ($existing_field_options && $widget_type_options) {
    $name = '_add_existing_field';
    $table[$name] = array(
      '#attributes' => array('class' => array('draggable', 'tabledrag-leaf', 'add-new')),
      '#row_type' => 'add_new_field',
      '#region_callback' => 'field_ui_field_overview_row_region',
      'label' => array(
        '#type' => 'textfield',
        '#title' => t('Existing field label'),
        '#title_display' => 'invisible',
        '#size' => 15,
        '#description' => t('Label'),
        '#attributes' => array('class' => array('label-textfield')),
        '#prefix' => '<div class="label-input"><div class="add-new-placeholder">' . t('Add existing field') .'</div>',
        '#suffix' => '</div>',
      ),
      'weight' => array(
        '#type' => 'textfield',
        '#default_value' => $max_weight + 2,
        '#size' => 3,
        '#title_display' => 'invisible',
        '#title' => t('Weight for added field'),
        '#attributes' => array('class' => array('field-weight')),
        '#prefix' => '<div class="add-new-placeholder">&nbsp;</div>',
      ),
      'parent_wrapper' => array(
        'parent' => array(
          '#type' => 'select',
          '#title' => t('Parent for existing field'),
          '#title_display' => 'invisible',
          '#options' => $table['#parent_options'],
          '#empty_value' => '',
          '#attributes' => array('class' => array('field-parent')),
          '#prefix' => '<div class="add-new-placeholder">&nbsp;</div>',
          '#parents' => array('fields', $name, 'parent'),
        ),
        'hidden_name' => array(
          '#type' => 'hidden',
          '#default_value' => $name,
          '#attributes' => array('class' => array('field-name')),
        ),
      ),
      'field_name' => array(
        '#type' => 'select',
        '#title' => t('Existing field to share'),
        '#title_display' => 'invisible',
        '#options' => $existing_field_options,
        '#empty_option' => t('- Select an existing field -'),
        '#description' => t('Field to share'),
        '#attributes' => array('class' => array('field-select')),
        '#cell_attributes' => array('colspan' => 2),
        '#prefix' => '<div class="add-new-placeholder">&nbsp;</div>',
      ),
      'widget_type' => array(
        '#type' => 'select',
        '#title' => t('Widget for existing field'),
        '#title_display' => 'invisible',
        '#options' => $widget_type_options,
        '#empty_option' => t('- Select a widget -'),
        '#description' => t('Form element to edit the data.'),
        '#attributes' => array('class' => array('widget-type-select')),
        '#cell_attributes' => array('colspan' => 3),
        '#prefix' => '<div class="add-new-placeholder">&nbsp;</div>',
      ),
    );
  }
  $form['fields'] = $table;

  $form['actions'] = array('#type' => 'actions');
  $form['actions']['submit'] = array('#type' => 'submit', '#value' => t('Save'));

  $form['#attached']['css'][] = drupal_get_path('module', 'field_ui') . '/field_ui.css';
  $form['#attached']['js'][] = drupal_get_path('module', 'field_ui') . '/field_ui.js';

  // Add settings for the update selects behavior.
  $js_fields = array();
  foreach ($existing_field_options as $field_name => $fields) {
    $field = field_info_field($field_name);
    $instance = field_info_instance($form['#entity_type'], $field_name, $form['#bundle']);
    $js_fields[$field_name] = array('label' => $instance['label'], 'type' => $field['type'], 'widget' => $instance['widget']['type']);
  }

  $form['#attached']['js'][] = array(
    'type' => 'setting',
    'data' => array('fields' => $js_fields, 'fieldWidgetTypes' => field_ui_widget_type_options()),
  );

  // Add tabledrag behavior.
  $form['#attached']['drupal_add_tabledrag'][] = array('field-overview', 'order', 'sibling', 'field-weight');
  $form['#attached']['drupal_add_tabledrag'][] = array('field-overview', 'match', 'parent', 'field-parent', 'field-parent', 'field-name');

  return $form;
}

/**
 * Validate handler for the field overview form.
 */
function field_ui_field_overview_form_validate($form, &$form_state) {
  _field_ui_field_overview_form_validate_add_new($form, $form_state);
  _field_ui_field_overview_form_validate_add_existing($form, $form_state);
}

/**
 * Helper function for field_ui_field_overview_form_validate.
 *
 * Validate the 'add new field' row.
 */
function _field_ui_field_overview_form_validate_add_new($form, &$form_state) {
  $field = $form_state['values']['fields']['_add_new_field'];

  // Validate if any information was provided in the 'add new field' row.
  if (array_filter(array($field['label'], $field['field_name'], $field['type'], $field['widget_type']))) {
    // Missing label.
    if (!$field['label']) {
      form_set_error('fields][_add_new_field][label', t('Add new field: you need to provide a label.'));
    }

    // Missing field name.
    if (!$field['field_name']) {
      form_set_error('fields][_add_new_field][field_name', t('Add new field: you need to provide a field name.'));
    }
    // Field name validation.
    else {
      $field_name = $field['field_name'];

      // Add the 'field_' prefix.
      if (substr($field_name, 0, 6) != 'field_') {
        $field_name = 'field_' . $field_name;
        form_set_value($form['fields']['_add_new_field']['field_name'], $field_name, $form_state);
      }

      // Invalid field name.
      if (!preg_match('!^field_[a-z0-9_]+$!', $field_name)) {
        form_set_error('fields][_add_new_field][field_name', t('Add new field: the field name %field_name is invalid. The name must include only lowercase unaccentuated letters, numbers, and underscores.', array('%field_name' => $field_name)));
      }
      if (strlen($field_name) > 32) {
        form_set_error('fields][_add_new_field][field_name', t("Add new field: the field name %field_name is too long. The name is limited to 32 characters, including the 'field_' prefix.", array('%field_name' => $field_name)));
      }

      // Field name already exists. We need to check inactive fields as well, so
      // we can't use field_info_fields().
      $fields = field_read_fields(array('field_name' => $field_name), array('include_inactive' => TRUE));
      if ($fields) {
        form_set_error('fields][_add_new_field][field_name', t('Add new field: the field name %field_name already exists.', array('%field_name' => $field_name)));
      }
    }

    // Missing field type.
    if (!$field['type']) {
      form_set_error('fields][_add_new_field][type', t('Add new field: you need to select a field type.'));
    }

    // Missing widget type.
    if (!$field['widget_type']) {
      form_set_error('fields][_add_new_field][widget_type', t('Add new field: you need to select a widget.'));
    }
    // Wrong widget type.
    elseif ($field['type']) {
      $widget_types = field_ui_widget_type_options($field['type']);
      if (!isset($widget_types[$field['widget_type']])) {
        form_set_error('fields][_add_new_field][widget_type', t('Add new field: invalid widget.'));
      }
    }
  }
}

/**
 * Helper function for field_ui_field_overview_form_validate.
 *
 * Validate the 'add existing field' row.
 */
function _field_ui_field_overview_form_validate_add_existing($form, &$form_state) {
  // The form element might be absent if no existing fields can be added to
  // this bundle.
  if (isset($form_state['values']['fields']['_add_existing_field'])) {
    $field = $form_state['values']['fields']['_add_existing_field'];

    // Validate if any information was provided in the 'add existing field' row.
    if (array_filter(array($field['label'], $field['field_name'], $field['widget_type']))) {
      // Missing label.
      if (!$field['label']) {
        form_set_error('fields][_add_existing_field][label', t('Add existing field: you need to provide a label.'));
      }

      // Missing existing field name.
      if (!$field['field_name']) {
        form_set_error('fields][_add_existing_field][field_name', t('Add existing field: you need to select a field.'));
      }

      // Missing widget type.
      if (!$field['widget_type']) {
        form_set_error('fields][_add_existing_field][widget_type', t('Add existing field: you need to select a widget.'));
      }
      // Wrong widget type.
      elseif ($field['field_name'] && ($existing_field = field_info_field($field['field_name']))) {
        $widget_types = field_ui_widget_type_options($existing_field['type']);
        if (!isset($widget_types[$field['widget_type']])) {
          form_set_error('fields][_add_existing_field][widget_type', t('Add existing field: invalid widget.'));
        }
      }
    }
  }
}

/**
 * Submit handler for the field overview form.
 */
function field_ui_field_overview_form_submit($form, &$form_state) {
  $form_values = $form_state['values']['fields'];
  $entity_type = $form['#entity_type'];
  $bundle = $form['#bundle'];
  $admin_path = _field_ui_bundle_admin_path($entity_type, $bundle);

  $bundle_settings = field_bundle_settings($entity_type, $bundle);

  // Update field weights.
  foreach ($form_values as $key => $values) {
    if (in_array($key, $form['#fields'])) {
      $instance = field_read_instance($entity_type, $key, $bundle);
      $instance['widget']['weight'] = $values['weight'];
      field_update_instance($instance);
    }
    elseif (in_array($key, $form['#extra'])) {
      $bundle_settings['extra_fields']['form'][$key]['weight'] = $values['weight'];
    }
  }

  field_bundle_settings($entity_type, $bundle, $bundle_settings);

  $destinations = array();

  // Create new field.
  $field = array();
  if (!empty($form_values['_add_new_field']['field_name'])) {
    $values = $form_values['_add_new_field'];

    $field = array(
      'field_name' => $values['field_name'],
      'type' => $values['type'],
      'translatable' => $values['translatable'],
    );
    $instance = array(
      'field_name' => $field['field_name'],
      'entity_type' => $entity_type,
      'bundle' => $bundle,
      'label' => $values['label'],
      'widget' => array(
        'type' => $values['widget_type'],
        'weight' => $values['weight'],
      ),
    );

    // Create the field and instance.
    try {
      field_create_field($field);
      field_create_instance($instance);

      $destinations[] = $admin_path . '/fields/' . $field['field_name'] . '/field-settings';
      $destinations[] = $admin_path . '/fields/' . $field['field_name'];

      // Store new field information for any additional submit handlers.
      $form_state['fields_added']['_add_new_field'] = $field['field_name'];
    }
    catch (Exception $e) {
      drupal_set_message(t('There was a problem creating field %label: @message.', array('%label' => $instance['label'], '@message' => $e->getMessage())));
    }
  }

  // Add existing field.
  if (!empty($form_values['_add_existing_field']['field_name'])) {
    $values = $form_values['_add_existing_field'];
    $field = field_info_field($values['field_name']);
    if (!empty($field['locked'])) {
      drupal_set_message(t('The field %label cannot be added because it is locked.', array('%label' => $values['label'])));
    }
    else {
      $instance = array(
        'field_name' => $field['field_name'],
        'entity_type' => $entity_type,
        'bundle' => $bundle,
        'label' => $values['label'],
        'widget' => array(
          'type' => $values['widget_type'],
          'weight' => $values['weight'],
        ),
      );

      try {
        field_create_instance($instance);
        $destinations[] = $admin_path . '/fields/' . $instance['field_name'] . '/edit';
        // Store new field information for any additional submit handlers.
        $form_state['fields_added']['_add_existing_field'] = $instance['field_name'];
      }
      catch (Exception $e) {
        drupal_set_message(t('There was a problem creating field instance %label: @message.', array('%label' => $instance['label'], '@message' => $e->getMessage())));
      }
    }
  }

  if ($destinations) {
    $destination = drupal_get_destination();
    $destinations[] = $destination['destination'];
    unset($_GET['destination']);
    $form_state['redirect'] = field_ui_get_destinations($destinations);
  }
  else {
    drupal_set_message(t('Your settings have been saved.'));
  }
}

/**
 * Menu callback; presents field display settings for a given view mode.
 */
function field_ui_display_overview_form($form, &$form_state, $entity_type, $bundle, $view_mode) {
  $bundle = field_extract_bundle($entity_type, $bundle);

  field_ui_inactive_message($entity_type, $bundle);
  $admin_path = _field_ui_bundle_admin_path($entity_type, $bundle);

  // Gather type information.
  $instances = field_info_instances($entity_type, $bundle);
  $field_types = field_info_field_types();
  $extra_fields = field_info_extra_fields($entity_type, $bundle, 'display');

  $form_state += array(
    'formatter_settings_edit' => NULL,
  );

  $form += array(
    '#entity_type' => $entity_type,
    '#bundle' => $bundle,
    '#view_mode' => $view_mode,
    '#fields' => array_keys($instances),
    '#extra' => array_keys($extra_fields),
  );

  if (empty($instances) && empty($extra_fields)) {
    drupal_set_message(t('There are no fields yet added. You can add new fields on the <a href="@link">Manage fields</a> page.', array('@link' => url($admin_path . '/fields'))), 'warning');
    return $form;
  }

  $table = array(
    '#type' => 'field_ui_table',
    '#tree' => TRUE,
    '#header' => array(
      t('Field'),
      t('Weight'),
      t('Parent'),
      t('Label'),
      array('data' => t('Format'), 'colspan' => 3),
    ),
    '#regions' => array(
      'visible' => array('message' => t('No field is displayed.')),
      'hidden' => array('title' => t('Hidden'), 'message' => t('No field is hidden.')),
    ),
    '#parent_options' => array(),
    '#attributes' => array(
      'class' => array('field-ui-overview'),
      'id' => 'field-display-overview',
    ),
    // Add Ajax wrapper.
    '#prefix' => '<div id="field-display-overview-wrapper">',
    '#suffix' => '</div>',
  );

  $field_label_options = array(
    'above' => t('Above'),
    'inline' => t('Inline'),
    'hidden' => t('<Hidden>'),
  );
  $extra_visibility_options = array(
    'visible' => t('Visible'),
    'hidden' => t('Hidden'),
  );

  // Field rows.
  foreach ($instances as $name => $instance) {
    $field = field_info_field($instance['field_name']);
    $display = $instance['display'][$view_mode];
    $table[$name] = array(
      '#attributes' => array('class' => array('draggable', 'tabledrag-leaf')),
      '#row_type' => 'field',
      '#region_callback' => 'field_ui_display_overview_row_region',
      '#js_settings' => array(
        'rowHandler' => 'field',
        'defaultFormatter' => $field_types[$field['type']]['default_formatter'],
      ),
      'human_name' => array(
        '#markup' => check_plain($instance['label']),
      ),
      'weight' => array(
        '#type' => 'textfield',
        '#title' => t('Weight for @title', array('@title' => $instance['label'])),
        '#title_display' => 'invisible',
        '#default_value' => $display['weight'],
        '#size' => 3,
        '#attributes' => array('class' => array('field-weight')),
      ),
      'parent_wrapper' => array(
        'parent' => array(
          '#type' => 'select',
          '#title' => t('Label display for @title', array('@title' => $instance['label'])),
          '#title_display' => 'invisible',
          '#options' => $table['#parent_options'],
          '#empty_value' => '',
          '#attributes' => array('class' => array('field-parent')),
          '#parents' => array('fields', $name, 'parent'),
        ),
        'hidden_name' => array(
          '#type' => 'hidden',
          '#default_value' => $name,
          '#attributes' => array('class' => array('field-name')),
        ),
      ),
      'label' => array(
        '#type' => 'select',
        '#title' => t('Label display for @title', array('@title' => $instance['label'])),
        '#title_display' => 'invisible',
        '#options' => $field_label_options,
        '#default_value' => $display['label'],
      ),
    );

    $formatter_options = field_ui_formatter_options($field['type']);
    $formatter_options['hidden'] = t('<Hidden>');
    $table[$name]['format'] = array(
      'type' => array(
        '#type' => 'select',
        '#title' => t('Formatter for @title', array('@title' => $instance['label'])),
        '#title_display' => 'invisible',
        '#options' => $formatter_options,
        '#default_value' => $display['type'],
        '#parents' => array('fields', $name, 'type'),
        '#attributes' => array('class' => array('field-formatter-type')),
      ),
      'settings_edit_form' => array(),
    );

    // Formatter settings.

    // Check the currently selected formatter, and merge persisted values for
    // formatter settings.
    if (isset($form_state['values']['fields'][$name]['type'])) {
      $formatter_type = $form_state['values']['fields'][$name]['type'];
    }
    else {
      $formatter_type = $display['type'];
    }
    if (isset($form_state['formatter_settings'][$name])) {
      $settings = $form_state['formatter_settings'][$name];
    }
    else {
      $settings = $display['settings'];
    }
    $settings += field_info_formatter_settings($formatter_type);

    $instance['display'][$view_mode]['type'] = $formatter_type;
    $formatter = field_info_formatter_types($formatter_type);
    $instance['display'][$view_mode]['module'] = $formatter['module'];
    $instance['display'][$view_mode]['settings'] = $settings;

    // Base button element for the various formatter settings actions.
    $base_button = array(
      '#submit' => array('field_ui_display_overview_multistep_submit'),
      '#ajax' => array(
        'callback' => 'field_ui_display_overview_multistep_js',
        'wrapper' => 'field-display-overview-wrapper',
        'effect' => 'fade',
      ),
      '#field_name' => $name,