drupal/modules/simpletest/tests/field_test.module

<?php
// $Id$

define('FIELD_TEST_ELEMENT_ID', 1);
define('FIELD_TEST_BUNDLE', 'test_bundle');

/**
 * Implement hook_permission().
 */
function field_test_permission() {
  $perms = array(
    'access field_test content' => array(
      'title' => t('Access field_test content'),
      'description' => t('View published field_test content.'),
    ),
    'administer field_test content' => array(
      'title' => t('Administer field_test content'),
      'description' => t('Manage field_test content'),
    ),
  );
  return $perms;
}

/**
 * Implement hook_menu().
 */
function field_test_menu() {
  $items = array();
  $bundles = field_info_bundles('test_entity');

  foreach ($bundles as $bundle_name => $bundle_info) {
    $bundle_url_str = str_replace('_', '-', $bundle_name);
    $items['test-entity/add/' . $bundle_url_str] = array(
      'title' => t('Add %bundle test_entity', array('%bundle' => $bundle_info['label'])),
      'page callback' => 'field_test_entity_add',
      'page arguments' => array(2),
      'access arguments' => array('administer field_test content'),
      'type' => MENU_NORMAL_ITEM,
    );
  }
  $items['test-entity/%field_test_entity_test/edit'] = array(
    'title' => 'Edit test entity',
    'page callback' => 'field_test_entity_edit',
    'page arguments' => array(1),
    'access arguments' => array('administer field_test content'),
    'type' => MENU_NORMAL_ITEM,
  );

  return $items;
}


/**
 *
 * 'Field attach' API.
 *
 */


/**
 * Define a test fieldable entity.
 */
function field_test_entity_info() {
  $bundles = variable_get('field_test_bundles', array('test_bundle' => array('label' => 'Test Bundle')));
  return array(
    'test_entity' => array(
      'name' => t('Test Entity'),
      'object keys' => array(
        'id' => 'ftid',
        'revision' => 'ftvid',
        'bundle' => 'fttype',
      ),
      'cacheable' => FALSE,
      'bundles' => $bundles,
      'fieldable' => TRUE,
    ),
    // This entity type doesn't get form handling for now...
    'test_cacheable_entity' => array(
      'name' => t('Test Entity, cacheable'),
      'object keys' => array(
        'id' => 'ftid',
        'revision' => 'ftvid',
        'bundle' => 'fttype',
      ),
      'fieldable' => TRUE,
      'cacheable' => TRUE,
      'bundles' => $bundles,
    ),
  );
}

/**
 * Implement hook_entity_info_alter().
 */
function field_test_entity_info_alter(&$entity_info) {
  // Enable/disable field_test as a translation handler.
  foreach (field_test_entity_info_translatable() as $obj_type => $translatable) {
    $entity_info[$obj_type]['translation']['field_test'] = $translatable;
  }
  // Disable locale as a translation handler.
  foreach (field_info_fieldable_types() as $obj_type => $info) {
    $entity_info[$obj_type]['translation']['locale'] = FALSE;
  }
}

/**
 * Create a new bundle for test_entity objects.
 *
 * @param $bundle
 *   The machine-readable name of the bundle.
 * @param $text
 *   The human-readable name of the bundle. If none is provided, the machine
 *   name will be used.
 */
function field_test_create_bundle($bundle, $text = NULL) {
  $bundles = variable_get('field_test_bundles', array('test_bundle' => array('label' => 'Test Bundle')));
  $bundles += array($bundle => array('label' => $text ? $text : $bundle));
  variable_set('field_test_bundles', $bundles);

  $info = field_test_entity_info();
  foreach ($info as $type => $type_info) {
    field_attach_create_bundle($type, $bundle);
  }
}

/**
 * Rename a bundle for test_entity objects.
 *
 * @param $bundle_old
 *   The machine-readable name of the bundle to rename.
 * @param $bundle_new
 *   The new machine-readable name of the bundle.
 */
function field_test_rename_bundle($bundle_old, $bundle_new) {
  $bundles = variable_get('field_test_bundles', array('test_bundle' => array('label' => 'Test Bundle')));
  $bundles[$bundle_new] = $bundles[$bundle_old];
  unset($bundles[$bundle_old]);
  variable_set('field_test_bundles', $bundles);

  $info = field_test_entity_info();
  foreach ($info as $type => $type_info) {
    field_attach_rename_bundle($type, $bundle_old, $bundle_new);
  }
}

/**
 * Delete a bundle for test_entity objects.
 *
 * @param $bundle
 *   The machine-readable name of the bundle to delete.
 */
function field_test_delete_bundle($bundle) {
  $bundles = variable_get('field_test_bundles', array('test_bundle' => array('label' => 'Test Bundle')));
  unset($bundles[$bundle]);
  variable_set('field_test_bundles', $bundles);

  $info = field_test_entity_info();
  foreach ($info as $type => $type_info) {
    field_attach_delete_bundle($type, $bundle);
  }
}

/**
 * Implement hook_field_build_modes().
 */
function field_test_field_build_modes($obj_type) {
  $modes = array();
  if ($obj_type == 'test_entity' || $obj_type == 'test_cacheable_entity') {
    $modes = array(
      'full' => t('Full node'),
      'teaser' => t('Teaser'),
    );
  }
  return $modes;
}

/**
 * Helper function to create a basic 'test entity' structure.
 *
 * TODO : do we stil need this now that we can actualy load and save test_entities ?
 */
function field_test_create_stub_entity($id = 1, $vid = 1, $bundle = FIELD_TEST_BUNDLE) {
  $entity = new stdClass();
  // Only set id and vid properties if they don't come as NULL (creation form).
  if (isset($id)) {
    $entity->ftid = $id;
  }
  if (isset($vid)) {
    $entity->ftvid = $vid;
  }
  $entity->fttype = $bundle;

  return $entity;
}

function field_test_entity_test_load($ftid, $ftvid = NULL) {
  // Load basic strucure.
  $query = db_select('test_entity', 'fte', array())
    ->fields('fte')
    ->condition('ftid', $ftid);
  if ($ftvid) {
    $query->condition('ftvid', $ftvid);
  }
  $entities = $query->execute()->fetchAllAssoc('ftid');

  // Attach fields.
  if ($ftvid) {
    field_attach_load_revision('test_entity', $entities);
  }
  else {
    field_attach_load('test_entity', $entities);
  }

  return $entities[$ftid];
}

function field_test_entity_save(&$entity) {
  field_attach_presave('test_entity', $entity);

  if (!isset($entity->is_new)) {
    $entity->is_new = empty($entity->ftid);
  }

  if (!$entity->is_new && !empty($entity->revision)) {
    $entity->old_ftvid = $entity->ftvid;
    unset($entity->ftvid);
  }

  $update_entity = TRUE;
  if ($entity->is_new) {
    drupal_write_record('test_entity', $entity);
    drupal_write_record('test_entity_revision', $entity);
    $op = 'insert';
  }
  else {
    drupal_write_record('test_entity', $entity, 'ftid');
    if (!empty($entity->revision)) {
      drupal_write_record('test_entity_revision', $entity);
    }
    else {
      drupal_write_record('test_entity_revision', $entity, 'ftvid');
      $update_entity = FALSE;
    }
    $op = 'update';
  }
  if ($update_entity) {
    db_update('test_entity')
      ->fields(array('ftvid' => $entity->ftvid))
      ->condition('ftid', $entity->ftid)
      ->execute();
  }

  // Save fields.
  $function = "field_attach_$op";
  $function('test_entity', $entity);
}

function field_test_entity_add($fttype) {
  $fttype = str_replace('-', '_', $fttype);
  $entity = (object)array('fttype' => $fttype);
  drupal_set_title(t('Create test_entity @bundle', array('@bundle' => $fttype)), PASS_THROUGH);
  return drupal_get_form('field_test_entity_form', $entity);
}

function field_test_entity_edit($entity) {
  drupal_set_title(t('test_entity @ftid revision @ftvid', array('@ftid' => $entity->ftid, '@ftvid' => $entity->ftvid)), PASS_THROUGH);
  return drupal_get_form('field_test_entity_form', $entity);
}

/**
 * Form to set the value of fields attached to our entity.
 */
function field_test_entity_form($form, &$form_state, $entity) {
  if (isset($form_state['test_entity'])) {
    $entity = $form_state['test_entity'] + (array)$entity;
  }
  $entity = (object)$entity;

  foreach (array('ftid', 'ftvid', 'fttype') as $key) {
    $form[$key] = array(
      '#type' => 'value',
      '#value' => isset($entity->$key) ? $entity->$key : NULL,
    );
  }

  // Add field widgets.
  $form['#builder_function'] = 'field_test_entity_form_submit_builder';
  field_attach_form('test_entity', $entity, $form, $form_state);

  $form['revision'] = array(
    '#access' => user_access('administer field_test content'),
    '#type' => 'checkbox',
    '#title' => t('Create new revision'),
    '#default_value' => FALSE,
    '#weight' => 100,
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save'),
    '#weight' => 101,
  );

  return $form;
}

/**
 * Validate handler for field_test_set_field_values().
 */
function field_test_entity_form_validate($form, &$form_state) {
  $entity = field_test_create_stub_entity($form_state['values']['ftid'], $form_state['values']['ftvid'], $form_state['values']['fttype']);
  field_attach_form_validate('test_entity', $entity, $form, $form_state);
}

/**
 * Submit handler for field_test_set_field_values().
 */
function field_test_entity_form_submit($form, &$form_state) {
  $entity = field_test_entity_form_submit_builder($form, $form_state);
  $insert = empty($entity->ftid);
  field_test_entity_save($entity);

  $message = $insert ? t('test_entity @id has been created.', array('@id' => $entity->ftid)) : t('test_entity @id has been updated.', array('@id' => $entity->ftid));
  drupal_set_message($message);

  if ($entity->ftid) {
    unset($form_state['rebuild']);
    $form_state['redirect'] = 'test-entity/' . $entity->ftid . '/edit';
  }
  else {
    // Error on save.
    drupal_set_message(t('The entity could not be saved.'), 'error');
  }

}

/**
 * Build a test_entity by processing submitted form values and prepare for a form rebuild.
 */
function field_test_entity_form_submit_builder($form, &$form_state) {
  $entity = field_test_create_stub_entity($form_state['values']['ftid'], $form_state['values']['ftvid'], $form_state['values']['fttype']);
  field_attach_submit('test_entity', $entity, $form, $form_state);

  $form_state['test_entity'] = (array)$entity;
  $form_state['rebuild'] = TRUE;

  return $entity;
}

/**
 *
 * 'Field type' API.
 *
 */

/**
 * Implement hook_field_info().
 *
 * This field provides a textfield which only accepts the value 1.
 */
function field_test_field_info() {
  return array(
    'test_field' => array(
      'label' => t('Test Field'),
      'settings' => array(
        'test_field_setting' => 'dummy test string',
        'changeable' => 'a changeable field setting',
        'unchangeable' => 'an unchangeable field setting',
      ),
      'instance_settings' => array(
        'test_instance_setting' => 'dummy test string',
        'test_hook_field_load' => FALSE,
      ),
      'default_widget' => 'test_field_widget',
      'default_formatter' => 'field_test_default',
    ),
  );
}

/**
 * Implement hook_field_update_forbid().
 */
function field_test_field_update_forbid($field, $prior_field, $has_data) {
  if ($field['type'] == 'test_field' && $field['settings']['unchangeable'] != $prior_field['settings']['unchangeable']) {
    throw new FieldException("field_test 'unchangeable' setting cannot be changed'");
  }
}

/**
 * Implement hook_field_schema().
 */
function field_test_field_schema($field) {
  return array(
    'columns' => array(
      'value' => array(
        'type' => 'int',
        'size' => 'tiny',
        'not null' => FALSE,
      ),
    ),
    'indexes' => array(
      'value' => array('value'),
    ),
  );
}

/**
 * Implement hook_field_load().
 */
function field_test_field_load($obj_type, $objects, $field, $instances, $langcode, &$items, $age) {
  foreach ($items as $id => $item) {
    // To keep the test non-intrusive, only act for instances with the
    // test_hook_field_load setting explicitly set to TRUE.
    if ($instances[$id]['settings']['test_hook_field_load']) {
      foreach ($item as $delta => $value) {
        // Don't add anything on empty values.
        if ($value) {
          $items[$id][$delta]['additional_key'] = 'additional_value';
        }
      }
    }
  }
}

/**
 * Implement hook_field_validate().
 *
 * Possible error codes:
 * - 'field_test_invalid': The value is invalid.
 */
function field_test_field_validate($obj_type, $object, $field, $instance, $langcode, $items, &$errors) {
  foreach ($items as $delta => $item) {
    if ($item['value'] == -1) {
      $errors[$field['field_name']][$langcode][$delta][] = array(
        'error' => 'field_test_invalid',
        'message' => t('%name does not accept the value -1.', array('%name' => $instance['label'])),
      );
    }
  }
}

/**
 * Implement hook_field_sanitize().
 */
function field_test_field_sanitize($obj_type, $object, $field, $instance, $langcode, &$items) {
  foreach ($items as $delta => $item) {
    $value = check_plain($item['value']);
    $items[$delta]['safe'] = $value;
  }
}

/**
 * Implement hook_field_is_empty().
 */
function field_test_field_is_empty($item, $field) {
  return empty($item['value']);
}

/**
 * Implement hook_field_widget_info().
 *
 * Here we indicate that the field module will handle
 * the default value and multiple values for these widgets.
 *
 * Callbacks can be omitted if default handing is used.
 * They're included here just so this module can be used
 * as an example for custom modules that might do things
 * differently.
 */
function field_test_field_widget_info() {
  return array(
    'test_field_widget' => array(
      'label' => t('Test field'),
      'field types' => array('test_field'),
      'settings' => array('test_widget_setting' => 'dummy test string'),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_DEFAULT,
        'default value' => FIELD_BEHAVIOR_DEFAULT,
      ),
    ),
    'test_field_widget_multiple' => array(
      'label' => t('Test field 1'),
      'field types' => array('test_field'),
      'settings' => array('test_widget_setting_multiple' => 'dummy test string'),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_CUSTOM,
        'default value' => FIELD_BEHAVIOR_DEFAULT,
      ),
    ),
  );
}

/**
 * Implement hook_field_widget().
 *
 * Attach a single form element to the form. It will be built out and
 * validated in the callback(s) listed in hook_element_info(). We build it
 * out in the callbacks rather than here in hook_widget so it can be
 * plugged into any module that can provide it with valid
 * $field information.
 *
 * If there are multiple values for this field, the field module will
 * call this function as many times as needed.
 *
 * @param $form
 *   the entire form array, $form['#node'] holds node information
 * @param $form_state
 *   the form_state, $form_state['values'][$field['field_name']]
 *   holds the field's form values.
 * @param $field
 *   The field structure.
 * @param $instance
 *   the instance array
 * @param $items
 *   array of default values for this field
 * @param $delta
 *   the order of this item in the array of subelements (0, 1, 2, etc)
 *
 * @return
 *   the form item for a single element for this field
 */
function field_test_field_widget(&$form, &$form_state, $field, $instance, $langcode, $items, $delta = 0) {
  $element = array(
    'value' => array(
      '#title' => $instance['label'],
      '#type' => 'textfield',
      '#default_value' => isset($items[$delta]['value']) ? $items[$delta]['value'] : '',
      '#required' => $instance['required'],
    ),
  );
  return $element;
}

/**
 * Implement hook_field_widget_error().
 */
function field_test_field_widget_error($element, $error) {
  form_error($element['value'], $error['message']);
}

/**
 * Implement hook_field_formatter_info().
 */
function field_test_field_formatter_info() {
  return array(
    'field_test_default' => array(
      'label' => t('Default'),
      'description' => t('Default formatter'),
      'field types' => array('test_field'),
      'settings' => array(
        'test_formatter_setting' => 'dummy test string',
      ),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_DEFAULT,
      ),
    ),
    'field_test_multiple' => array(
      'label' => t('Multiple'),
      'description' => t('Multiple formatter'),
      'field types' => array('test_field'),
      'settings' => array(
        'test_formatter_setting_multiple' => 'dummy test string',
      ),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_CUSTOM,
      ),
    ),
    'field_test_needs_additional_data' => array(
      'label' => t('Tests hook_field_formatter_prepare_view()'),
      'field types' => array('test_field'),
      'settings' => array(
        'test_formatter_setting_additional' => 'dummy test string',
      ),
    ),
  );
}

/**
 * Implement hook_theme().
 */
function field_test_theme() {
  return array(
    'field_formatter_field_test_default' => array(
      'render element' => 'element',
    ),
    'field_formatter_field_test_multiple' => array(
      'render element' => 'element',
    ),
    'field_formatter_field_test_needs_additional_data' => array(
      'render element' => 'element',
    ),
  );
}

/**
 * Implement hook_field_formatter_prepare_view().
 */
function field_test_field_formatter_prepare_view($obj_type, $objects, $field, $instances, $langcode, &$items, $build_mode) {
  foreach ($items as $id => $item) {
    // To keep the test non-intrusive, only act on the
    // 'field_test_needs_additional_data' formatter.
    if ($instances[$id]['display'][$build_mode]['type'] == 'field_test_needs_additional_data') {
      foreach ($item as $delta => $value) {
        // Don't add anything on empty values.
        if ($value) {
          $items[$id][$delta]['additional_formatter_value'] = $value['value'] + 1;
        }
      }
    }
  }
}

/**
 * Theme function for 'field_test_default' formatter.
 */
function theme_field_formatter_field_test_default($variables) {
  $element = $variables['element'];

  $value = $element['#item']['value'];
  $settings = $element['#settings'];

  return $settings['test_formatter_setting'] . '|' . $value;
}

/**
 * Theme function for 'field_test_multiple' formatter.
 */
function theme_field_formatter_field_test_multiple($variables) {
  $element = $variables['element'];

  $settings = $element['#settings'];

  $items = array();
  foreach (element_children($element) as $key) {
    $items[$key] = $key .':'. $element[$key]['#item']['value'];
  }
  $output = implode('|', $items);
  return $settings['test_formatter_setting_multiple'] . '|' . $output;
}

/**
 * Theme function for 'field_test_needs_additional_data' formatter.
 */
function theme_field_formatter_field_test_needs_additional_data($variables) {
  $element = $variables['element'];
  $value = $element['#item']['value'];
  $additional = $element['#item']['additional_formatter_value'];
  $settings = $element['#settings'];

  return $settings['test_formatter_setting_additional'] . '|' . $value . '|' . $additional;
}

/**
 * Sample function to test default value assignment.
 */
function field_test_default_value($obj_type, $object, $field, $instance) {
  return array(array('value' => 99));
}

/**
 * Generic op to test _field_invoke behavior.
 */
function field_test_field_test_op($obj_type, $object, $field, $instance, $langcode, &$items) {
  return array($langcode => md5(serialize(array($obj_type, $object, $field['field_name'], $langcode, $items))));
}

/**
 * Generic op to test _field_invoke_multiple behavior.
 */
function field_test_field_test_op_multiple($obj_type, $objects, $field, $instances, $langcode, &$items) {
  $result = array();
  foreach ($objects as $id => $object) {
    $result[$id] = array($langcode => md5(serialize(array($obj_type, $object, $field['field_name'], $langcode, $items[$id]))));
  }
  return $result;
}

/**
 * Implement hook_field_languages().
 */
function field_test_field_languages($obj_type, $field, &$languages) {
  if ($field['settings']['test_hook_in']) {
    // Add an unavailable language.
    $languages[] = 'xx';
    // Remove an available language.
    unset($languages[0]);
  }
}

/**
 * Helper function to enable entity translations.
 */
function field_test_entity_info_translatable($obj_type = NULL, $translatable = NULL) {
  $stored_value = &drupal_static(__FUNCTION__, array());
  if (isset($obj_type)) {
    $stored_value[$obj_type] = $translatable;
    _field_info_collate_types(TRUE);
  }
  return $stored_value;
}

/**
 *
 * 'Field storage' API.
 *
 */

/**
 * Implement hook_field_storage_info().
 */
function field_test_field_storage_info() {
  return array(
    'field_test_storage' => array(
      'label' => t('Test storage'),
      'description' => t('Dummy test storage backend. Stores field values in the variable table.'),
    ),
    'field_test_storage_failure' => array(
      'label' => t('Test storage failure'),
      'description' => t('Dummy test storage backend. Always fails to create fields.'),
    ),
  );
}

/**
 * Implement hook_field_storage_details().
 */
function field_test_field_storage_details($field, $instance) {
  $details = array();

  // Add field columns.
  $columns = array();
  foreach ((array) $field['columns'] as $column_name => $attributes) {
    $columns[$column_name] = $column_name;
  }
  return array(
    'drupal_variables' => array(
      'field_test_storage_data[FIELD_LOAD_CURRENT]' => $columns,
      'field_test_storage_data[FIELD_LOAD_REVISION]' => $columns,
    ),
  );
}

/**
 * Implement hook_field_storage_details_alter().
 *
 * @see FieldAttachStorageTestCase::testFieldStorageDetailsAlter()
 */
function field_test_field_storage_details_alter(&$details, $field, $instance) {

  // For testing, storage details are changed only because of the field name.
  if ($field['field_name'] == 'field_test_change_my_details') {
    $columns = array();
    foreach ((array) $field['columns'] as $column_name => $attributes) {
      $columns[$column_name] = $column_name;
    }
    $details['drupal_variables'] = array(
      FIELD_LOAD_CURRENT => array(
        'moon' => $columns,
      ),
      FIELD_LOAD_REVISION => array(
        'mars' => $columns,
      ),
    );
  }
}

/**
 * Helper function: store or retrieve data from the 'storage backend'.
 */
function _field_test_storage_data($data = NULL) {
  if (is_null($data)) {
    return variable_get('field_test_storage_data', array());
  }
  else {
    variable_set('field_test_storage_data', $data);
  }
}

/**
 * Implement hook_field_storage_load().
 */
function field_test_field_storage_load($obj_type, $objects, $age, $fields, $options) {
  $data = _field_test_storage_data();

  $load_current = $age == FIELD_LOAD_CURRENT;

  foreach ($fields as $field_id => $ids) {
    $field = field_info_field_by_id($field_id);
    $field_name = $field['field_name'];
    $field_data = $data[$field['id']];
    $sub_table = $load_current ? 'current' : 'revisions';
    $delta_count = array();
    foreach ($field_data[$sub_table] as $row) {
      if ($row->type == $obj_type && (!$row->deleted || $options['deleted'])) {
        if (($load_current && in_array($row->entity_id, $ids)) || (!$load_current && in_array($row->revision_id, $ids))) {
          if (in_array($row->language, field_multilingual_available_languages($obj_type, $field))) {
            if (!isset($delta_count[$row->entity_id][$row->language])) {
              $delta_count[$row->entity_id][$row->language] = 0;
            }
            if ($field['cardinality'] == FIELD_CARDINALITY_UNLIMITED || $delta_count[$row->entity_id][$row->language] < $field['cardinality']) {
              $item = array();
              foreach ($field['columns'] as $column => $attributes) {
                $item[$column] = $row->{$column};
              }
              $objects[$row->entity_id]->{$field_name}[$row->language][] = $item;
              $delta_count[$row->entity_id][$row->language]++;
            }
          }
        }
      }
    }
  }
}

/**
 * Implement hook_field_storage_write().
 */
function field_test_field_storage_write($obj_type, $object, $op, $fields) {
  $data = _field_test_storage_data();

  list($id, $vid, $bundle) = field_extract_ids($obj_type, $object);

  foreach ($fields as $field_id) {
    $field = field_info_field_by_id($field_id);
    $field_name = $field['field_name'];
    $field_data = &$data[$field_id];

    $all_languages = field_multilingual_available_languages($obj_type, $field);
    $field_languages = array_intersect($all_languages, array_keys((array) $object->$field_name));

    // Delete and insert, rather than update, in case a value was added.
    if ($op == FIELD_STORAGE_UPDATE) {
      // Delete languages present in the incoming $object->$field_name.
      // Delete all languages if $object->$field_name is empty.
      $languages = !empty($object->$field_name) ? $field_languages : $all_languages;
      if ($languages) {
        foreach ($field_data['current'] as $key => $row) {
          if ($row->type == $obj_type && $row->entity_id == $id && in_array($row->language, $languages)) {
            unset($field_data['current'][$key]);
          }
        }
        if (isset($vid)) {
          foreach ($field_data['revisions'] as $key => $row) {
            if ($row->type == $obj_type && $row->revision_id == $vid) {
              unset($field_data['revisions'][$key]);
            }
          }
        }
      }
    }

    foreach ($field_languages as $langcode) {
      $items = (array) $object->{$field_name}[$langcode];
      $delta_count = 0;
      foreach ($items as $delta => $item) {
        $row = (object) array(
          'field_id' => $field_id,
          'type' => $obj_type,
          'entity_id' => $id,
          'revision_id' => $vid,
          'bundle' => $bundle,
          'delta' => $delta,
          'deleted' => FALSE,
          'language' => $langcode,
        );
        foreach ($field['columns'] as $column => $attributes) {
          $row->{$column} = isset($item[$column]) ? $item[$column] : NULL;
        }

        $field_data['current'][] = $row;
        if (isset($vid)) {
          $field_data['revisions'][] = $row;
        }

        if ($field['cardinality'] != FIELD_CARDINALITY_UNLIMITED && ++$delta_count == $field['cardinality']) {
          break;
        }
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implement hook_field_storage_delete().
 */
function field_test_field_storage_delete($obj_type, $object, $fields) {
  list($id, $vid, $bundle) = field_extract_ids($obj_type, $object);

  // Note: reusing field_test_storage_purge(), like field_sql_storage.module
  // does, is highly inefficient in our case...
  foreach (field_info_instances($bundle) as $instance) {
    if (isset($fields[$instance['field_id']])) {
      $field = field_info_field_by_id($instance['field_id']);
      field_test_field_storage_purge($obj_type, $object, $field, $instance);
    }
  }
}

/**
 * Implement hook_field_storage_purge().
 */
function field_test_field_storage_purge($obj_type, $object, $field, $instance) {
  $data = _field_test_storage_data();

  list($id, $vid, $bundle) = field_extract_ids($obj_type, $object);

  $field_data = &$data[$field['id']];
  foreach (array('current', 'revisions') as $sub_table) {
    foreach ($field_data[$sub_table] as $key => $row) {
      if ($row->type == $obj_type && $row->entity_id == $id) {
        unset($field_data[$sub_table][$key]);
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implement hook_field_storage_delete_revision().
 */
function field_test_field_storage_delete_revision($obj_type, $object, $fields) {
  $data = _field_test_storage_data();

  list($id, $vid, $bundle) = field_extract_ids($obj_type, $object);
  foreach ($fields as $field_id) {
    $field_data = &$data[$field_id];
    foreach (array('current', 'revisions') as $sub_table) {
      foreach ($field_data[$sub_table] as $key => $row) {
        if ($row->type == $obj_type && $row->entity_id == $id && $row->revision_id == $vid) {
          unset($field_data[$sub_table][$key]);
        }
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implement hook_field_storage_query().
 */
function field_test_field_storage_query($field_id, $conditions, $count, &$cursor = NULL, $age) {
  $data = _field_test_storage_data();

  $load_current = $age == FIELD_LOAD_CURRENT;

  $field = field_info_field_by_id($field_id);
  $field_columns = array_keys($field['columns']);

  $field_data = $data[$field['id']];
  $sub_table = $load_current ? 'current' : 'revisions';
  // We need to sort records by object type and object id.
  usort($field_data[$sub_table], '_field_test_field_storage_query_sort_helper');

    // Initialize results array.
  $return = array();
  $obj_count = 0;
  $rows_count = 0;
  $rows_total = count($field_data[$sub_table]);
  $skip = $cursor;
  $skipped = 0;

  foreach ($field_data[$sub_table] as $row) {
    if ($count != FIELD_QUERY_NO_LIMIT && $obj_count >= $count) {
      break;
    }

    if ($row->field_id == $field['id']) {
      $match = TRUE;
      $condition_deleted = FALSE;
      // Add conditions.
      foreach ($conditions as $condition) {
        @list($column, $value, $operator) = $condition;
        if (empty($operator)) {
          $operator = is_array($value) ? 'IN' : '=';
        }
        switch ($operator) {
          case '=':
            $match = $match && $row->{$column} == $value;
            break;
          case '!=':
          case '<':
          case '<=':
          case '>':
          case '>=':
            eval('$match = $match && '. $row->{$column} . ' ' . $operator . ' '. $value);
            break;
          case 'IN':
            $match = $match && in_array($row->{$column}, $value);
            break;
          case 'NOT IN':
            $match = $match && !in_array($row->{$column}, $value);
            break;
          case 'BETWEEN':
            $match = $match && $row->{$column} >= $value[0] && $row->{$column} <= $value[1];
            break;
          case 'STARTS_WITH':
          case 'ENDS_WITH':
          case 'CONTAINS':
            // Not supported.
            $match = FALSE;
            break;
        }
        // Track condition on 'deleted'.
        if ($column == 'deleted') {
          $condition_deleted = TRUE;
        }
      }

      // Exclude deleted data unless we have a condition on it.
      if (!$condition_deleted && $row->deleted) {
        $match = FALSE;
      }

      if ($match) {
        if (is_null($skip) || $skipped >= $skip) {
          $cursor++;
          // If querying all revisions and the entity type has revisions, we need
          // to key the results by revision_ids.
          $entity_type = field_info_fieldable_types($row->type);
          $id = ($load_current || empty($entity_type['object keys']['revision'])) ? $row->entity_id : $row->revision_id;

          if (!isset($return[$row->type][$id])) {
            $return[$row->type][$id] = field_create_stub_entity($row->type, array($row->entity_id, $row->revision_id, $row->bundle));
            $obj_count++;
          }
        }
        else {
          $skipped++;
        }
      }
    }
    $rows_count++;

    // The query is complete if we walked the whole array.
    if ($count != FIELD_QUERY_NO_LIMIT && $rows_count >= $rows_total) {
      $cursor = FIELD_QUERY_COMPLETE;
    }
  }

  return $return;
}

/**
 * Sort helper for field_test_field_storage_query().
 *
 * Sort by object type and object id.
 */
function _field_test_field_storage_query_sort_helper($a, $b) {
  if ($a->type == $b->type) {
    if ($a->entity_id == $b->entity_id) {
      return 0;
    }
    else {
      return $a->entity_id < $b->entity_id ? -1 : 1;
    }
  }
  else {
    return $a->type < $b->type ? -1 : 1;
  }
}

/**
 * Implement hook_field_storage_create_field().
 */
function field_test_field_storage_create_field($field) {
  if ($field['storage']['type'] == 'field_test_storage_failure') {
    throw new Exception('field_test_storage_failure engine always fails to create fields');
  }
    
  $data = _field_test_storage_data();

  $data[$field['id']] = array(
    'current' => array(),
    'revisions' => array(),
  );

  _field_test_storage_data($data);
}

/**
 * Implement hook_field_storage_delete_field().
 */
function field_test_field_storage_delete_field($field) {
  $data = _field_test_storage_data();

  $field_data = &$data[$field['id']];
  foreach (array('current', 'revisions') as $sub_table) {
    foreach ($field_data[$sub_table] as &$row) {
      $row->deleted = TRUE;
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implement hook_field_storage_delete_instance().
 */
function field_test_field_storage_delete_instance($instance) {
  $data = _field_test_storage_data();

  $field = field_info_field($instance['field_name']);
  $field_data = &$data[$field['id']];
  foreach (array('current', 'revisions') as $sub_table) {
    foreach ($field_data[$sub_table] as &$row) {
      if ($row->bundle == $instance['bundle']) {
        $row->deleted = TRUE;
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implement hook_field_attach_create_bundle().
 */
function field_test_field_attach_create_bundle($bundle) {
  // We don't need to do anything here.
}

/**
 * Implement hook_field_attach_rename_bundle().
 */
function field_test_field_attach_rename_bundle($bundle_old, $bundle_new) {
  $data = _field_test_storage_data();

  // We need to account for deleted or inactive fields and instances.
  $instances = field_read_instances(array('bundle' => $bundle_new), array('include_deleted' => TRUE, 'include_inactive' => TRUE));
  foreach ($instances as $field_name => $instance) {
    $field = field_info_field_by_id($instance['field_id']);
    if ($field['storage']['type'] == 'field_test_storage') {
      $field_data = &$data[$field['id']];
      foreach (array('current', 'revisions') as $sub_table) {
        foreach ($field_data[$sub_table] as &$row) {
          if ($row->bundle == $bundle_old) {
            $row->bundle = $bundle_new;
          }
        }
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Implement hook_field_attach_delete_bundle().
 */
function field_test_field_attach_delete_bundle($bundle, $instances) {
  $data = _field_test_storage_data();

  $instances = field_info_instances($bundle);
  foreach ($instances as $field_name => $instance) {
    $field = field_info_field($field_name);
    if ($field['storage']['type'] == 'field_test_storage') {
      $field_data = &$data[$field['id']];
      foreach (array('current', 'revisions') as $sub_table) {
        foreach ($field_data[$sub_table] as &$row) {
          if ($row->bundle == $bundle_old) {
            $row->deleted = TRUE;
          }
        }
      }
    }
  }

  _field_test_storage_data($data);
}

/**
 * Store and retrieve keyed data for later verification by unit tests.
 *
 * This function is a simple in-memory key-value store with the
 * distinction that it stores all values for a given key instead of
 * just the most recently set value. field_test module hooks call
 * this function to record their arguments, keyed by hook name. The
 * unit tests later call this function to verify that the correct
 * hooks were called and were passed the correct arguments.
 *
 * This function ignores all calls until the first time it is called
 * with $key of NULL. Each time it is called with $key of NULL, it
 * erases all previously stored data from its internal cache, but also
 * returns the previously stored data to the caller. A typical usage
 * scenario is:
 *
 * @code
 *   // calls to field_test_memorize() here are ignored
 *
 *   // turn on memorization
 *   field_test_memorize();
 *
 *   // call some Field API functions that invoke field_test hooks
 *   $field = field_create_field(...);
 *
 *   // retrieve and reset the memorized hook call data
 *   $mem = field_test_memorize();
 *
 *   // make sure hook_field_create_field() is invoked correctly
 *   assertEqual(count($mem['field_test_field_create_field']), 1);
 *   assertEqual($mem['field_test_field_create_field'][0], array($field));
 * @endcode
 *
 * @param $key
 *   The key under which to store to $value, or NULL as described above.
 * @param $value
 *   A value to store for $key.
 * @return
 *   An array mapping each $key to an array of each $value passed in
 *   for that key.
 */
function field_test_memorize($key = NULL, $value = NULL) {
  $memorize = &drupal_static(__FUNCTION__, NULL);

  if (is_null($key)) {
    $return = $memorize;
    $memorize = array();
    return $return;
  }
  if (is_array($memorize)) {
    $memorize[$key][] = $value;
  }
}

/**
 * Memorize calls to hook_field_create_field().
 */
function field_test_field_create_field($field) {
  $args = func_get_args();
  field_test_memorize(__FUNCTION__, $args);
}

/**
 * Memorize calls to hook_field_insert().
 */
function field_test_field_insert($obj_type, $object, $field, $instance, $items) {
  $args = func_get_args();
  field_test_memorize(__FUNCTION__, $args);
}

/**
 * Memorize calls to hook_field_update().
 */
function field_test_field_update($obj_type, $object, $field, $instance, $items) {
  $args = func_get_args();
  field_test_memorize(__FUNCTION__, $args);
}

/**
 * Memorize calls to hook_field_delete().
 */
function field_test_field_delete($obj_type, $object, $field, $instance, $items) {
  $args = func_get_args();
  field_test_memorize(__FUNCTION__, $args);
}