performance-art.fr/sites/all/modules/contrib/fields/addressfield/plugins/format/address-hide-country.inc

<?php

/**
 * @file
 * Hide the country when only one country is available.
 */

$plugin = array(
  'title' => t('Hide the country when only one is available'),
  'format callback' => 'addressfield_format_address_hide_country',
  'type' => 'address',
  'weight' => -80,
);

/**
 * Format callback.
 *
 * @see CALLBACK_addressfield_format_callback()
 */
function addressfield_format_address_hide_country(&$format, $address, $context = array()) {
  // When building the format for a form, we expect the country element to have
  // an #options list. If it does, and there is only one option, hide the field
  // by setting #access to FALSE.
  if ($context['mode'] == 'form') {
    if (!empty($format['country']['#options']) && count($format['country']['#options']) == 1) {
      $format['country']['#access'] =  FALSE;
    }
  }
  elseif ($context['mode'] == 'render') {
    // However, in render mode, the element does not have an #options list, so
    // we look instead in the field instance settings if given. If we find a
    // single country option and it matches the country of the current address,
    // go ahead and hide it.
    if (!empty($context['instance']['widget']['settings']['available_countries']) &&
      count($context['instance']['widget']['settings']['available_countries']) == 1) {
      if (isset($context['instance']['widget']['settings']['available_countries'][$address['country']])) {
        $format['country']['#access'] = FALSE;
      }
    }
  }
}