gistfile1.php

<?php

/**
 * @file
 * Custom Entity Reference selection handler.
 */

class MyModuleSelectionHandler extends OgSelectionHandler {

  /**
   * Overrides OgSelectionHandler::getInstance().
   */
  public static function getInstance($field, $instance = NULL, $entity_type = NULL, $entity = NULL) {
    return new MyModuleSelectionHandler($field, $instance, $entity_type, $entity);
  }

  /**
   * Implements EntityReferenceHandler::settingsForm().
   *
   * Call directly from `EntityReference_SelectionHandler_Views`
   * since we can't extend that class.
   */
  public static function settingsForm($field, $instance) {
    $form = EntityReference_SelectionHandler_Views::settingsForm($field, $instance);

    // Add needed parameters from the OgSelectionHandler::settingsForm().
    $entity_type = $field['settings']['target_type'];
    $entity_info = entity_get_info($entity_type);

    $options = array();
    foreach (og_membership_type_load() as $og_membership) {
      $options[$og_membership->name] = $og_membership->description;
    }
    $form['membership_type'] = array(
      '#type' => 'select',
      '#title' => t('OG membership type'),
      '#description' => t('Select the membership type that will be used for a subscribing user.'),
      '#options' => $options,
      '#default_value' => OG_MEMBERSHIP_TYPE_DEFAULT,
      '#required' => TRUE,
    );

    // Hacky, but OG needs to know which bundles can be used, so hard code this.
    $bundles = array();
    foreach ($entity_info['bundles'] as $bundle_name => $bundle_info) {
      if (og_is_group_type($entity_type, $bundle_name)) {
        $bundles[$bundle_name] = $bundle_info['label'];
      }
    }

    if (!$bundles) {
      $form['target_bundles'] = array(
        '#type' => 'item',
        '#title' => t('Target bundles'),
        '#markup' => t('Error: The selected "Target type" %entity does not have bundles that are a group type', array('%entity' => $entity_info['label'])),
      );
    }
    else {
      $settings = $field['settings']['handler_settings'];
      $settings += array(
        'target_bundles' => array(),
      );

      $form['target_bundles'] = array(
        '#type' => 'select',
        '#title' => t('Target bundles'),
        '#options' => $bundles,
        '#default_value' => $settings['target_bundles'],
        '#size' => 6,
        '#multiple' => TRUE,
        '#description' => t('The bundles of the entity type acting as group, that can be referenced. Optional, leave empty for all bundles.')
      );
    }

    return $form;
  }

  /**
   * Copied directly from `EntityReference_SelectionHandler_Views` since we
   * can't extend this class.
   */
  protected function initializeView($match = NULL, $match_operator = 'CONTAINS', $limit = 0, $ids = NULL) {
    $view_name = $this->field['settings']['handler_settings']['view']['view_name'];
    $display_name = $this->field['settings']['handler_settings']['view']['display_name'];
    $args = $this->field['settings']['handler_settings']['view']['args'];
    $entity_type = $this->field['settings']['target_type'];

    // Check that the view is valid and the display still exists.
    $this->view = views_get_view($view_name);
    if (!$this->view || !isset($this->view->display[$display_name]) || !$this->view->access($display_name)) {
      watchdog('entityreference', 'The view %view_name is no longer eligible for the %field_name field.', array('%view_name' => $view_name, '%field_name' => $this->instance['label']), WATCHDOG_WARNING);
      return FALSE;
    }
    $this->view->set_display($display_name);

    // Make sure the query is not cached.
    $this->view->is_cacheable = FALSE;

    // Pass options to the display handler to make them available later.
    $entityreference_options = array(
      'match' => $match,
      'match_operator' => $match_operator,
      'limit' => $limit,
      'ids' => $ids,
    );
    $this->view->display_handler->set_option('entityreference_options', $entityreference_options);
    return TRUE;
  }

  /**
   * Implements EntityReferenceHandler::getReferencableEntities().
   *
   * Copied directly from `EntityReference_SelectionHandler_Views` since we
   * can't extend this class.
   */
  public function getReferencableEntities($match = NULL, $match_operator = 'CONTAINS', $limit = 0) {
    $display_name = $this->field['settings']['handler_settings']['view']['display_name'];
    $args = $this->field['settings']['handler_settings']['view']['args'];
    $result = array();
    if ($this->initializeView($match, $match_operator, $limit)) {
      // Get the results.
      $result = $this->view->execute_display($display_name, $args);
    }

    $return = array();
    if ($result) {
      $target_type = $this->field['settings']['target_type'];
      $entities = entity_load($target_type, array_keys($result));
      foreach ($entities as $entity) {
        list($id,, $bundle) = entity_extract_ids($target_type, $entity);
        $return[$bundle][$id] = $result[$id];
      }
    }
    return $return;
  }

  /**
   * Implements EntityReferenceHandler::countReferencableEntities().
   */
  function countReferencableEntities($match = NULL, $match_operator = 'CONTAINS') {
    $this->getReferencableEntities($match, $match_operator);
    return $this->view->total_items;
  }

  /**
   * Copied directly from `EntityReference_SelectionHandler_Views` since we
   * can't extend this class.
   */
  function validateReferencableEntities(array $ids) {
    $display_name = $this->field['settings']['handler_settings']['view']['display_name'];
    $args = $this->field['settings']['handler_settings']['view']['args'];
    $result = array();
    if ($this->initializeView(NULL, 'CONTAINS', 0, $ids)) {
      // Get the results.
      $entities = $this->view->execute_display($display_name, $args);
      $result = array_keys($entities);
    }
    return $result;
  }

  /**
   * Implements EntityReferenceHandler::validateAutocompleteInput().
   */
  public function validateAutocompleteInput($input, &$element, &$form_state, $form) {
    return NULL;
  }

  /**
   * Implements EntityReferenceHandler::getLabel().
   */
  public function getLabel($entity) {
    return entity_label($this->field['settings']['target_type'], $entity);
  }

  /**
   * Implements EntityReferenceHandler::entityFieldQueryAlter().
   */
  public function entityFieldQueryAlter(SelectQueryInterface $query) {

  }

}