Override the default autocomplete callback to allow more than 10 suggestions

This is especially important together with the "show all" functionality.

The node references module has the limit currently hardcoded to 10, so I had to supply a different autocomplete callback, where I did set it manually to 200. This should probably be configurable.

Here is the code, mostly copy & paste from the node references module:

/**
 * Implements hook_menu().
 */
function acdx_node_reference_menu() {
  $items['acdx_node_reference/autocomplete/%/%/%'] = array(
    'page callback' => 'acdx_node_reference_autocomplete',
    'page arguments' => array(2, 3, 4),
    'access callback' => 'reference_autocomplete_access',
    'access arguments' => array(2, 3, 4),
    'type' => MENU_CALLBACK,
  );
  return $items;
}

/**
 * Menu callback for the autocomplete results.
 */
function acdx_node_reference_autocomplete($entity_type, $bundle, $field_name, $string = '') {
  $field = field_info_field($field_name);
  $instance = field_info_instance($entity_type, $field_name, $bundle);

  $options = array(
    'string' => $string,
    'match' => $instance['widget']['settings']['autocomplete_match'],
    'limit' => 200,
  );
  $references = node_reference_potential_references($field, $options);

  $matches = array();
  foreach ($references as $id => $row) {
    // Markup is fine in autocompletion results (might happen when rendered
    // through Views) but we want to remove hyperlinks.
    $suggestion = preg_replace('/<a href="([^<]*)">([^<]*)<\/a>/', '$2', $row['rendered']);
    // Add a class wrapper for a few required CSS overrides.
    $matches[$row['title'] . " [nid:$id]"] = '<div class="reference-autocomplete">' . $suggestion . '</div>';
  }

  drupal_json_output($matches);
}


function acdx_node_reference_field_widget_info() {
  return array(
    'node_reference_autocomplete_deluxe' => array(
      'label'       => t('Autocomplete Deluxe'),
      'description' => t('Display the list of referenceable nodes as a textfield with autocomplete deluxe behaviour.'),
      'field types' => array('node_reference'),
      'settings'    => array(
        'autocomplete_match' => 'contains',
        'size' => 60,
        'autocomplete_path' => 'acdx_node_reference/autocomplete',
      ),
    ),

  );
}