i18n.module

<?php

/**
 * @file
 * Internationalization (i18n) module.
 *
 * This module extends multilingual support being the base module for the i18n package.
 * - Multilingual variables
 * - Extended languages for nodes
 * - Extended language API
 *
 * @author Jose A. Reyero, 2004
 */

// All multilingual options disabled
define('I18N_LANGUAGE_DISABLED', 0);
// Language list will include all enabled languages
define('I18N_LANGUAGE_ENABLED', 1);
// Language list will include also disabled languages
define('I18N_LANGUAGE_EXTENDED', 4);
// Disabled languages will be hidden when possible
define('I18N_LANGUAGE_HIDDEN', 8);
// All defined languages will be allowed but hidden when possible
define('I18N_LANGUAGE_EXTENDED_NOT_DISPLAYED', I18N_LANGUAGE_EXTENDED | I18N_LANGUAGE_HIDDEN);

// No multilingual options
define('I18N_MODE_NONE', 0);
// Localizable object. Run through the localization system
define('I18N_MODE_LOCALIZE', 1);
// Predefined language for this object and all related ones.
define('I18N_MODE_LANGUAGE', 2);
// Multilingual objects, translatable but not localizable.
define('I18N_MODE_TRANSLATE', 4);
// Objects are translatable (if they have language or localizable if not)
define('I18N_MODE_MULTIPLE', I18N_MODE_LOCALIZE | I18N_MODE_TRANSLATE);

/**
 * Implements hook_boot().
 */
function i18n_boot() {
  // Just make sure the module is loaded for boot and the API is available.
}

/**
 * Implements hook_hook_info().
 */
function i18n_hook_info() {
  $hooks['i18n_object_info'] = array(
    'group' => 'i18n',
  );
  return $hooks;
}

/**
 * Get global language object, make sure it is initialized
 *
 * @param $language
 *   Language code or language object to convert to valid language object
 */
function i18n_language($language = NULL) {
  if ($language) {
    if (is_object($language)) {
      return $language;
    }
    else {
      $list = language_list();
      return isset($list[$language]) ? $list[$language] : i18n_language();
    }
  }
  else {
    if (empty($GLOBALS['language'])) {
      // We don't have language yet, initialize the language system and retry
      drupal_bootstrap(DRUPAL_BOOTSTRAP_LANGUAGE);
    }
    return $GLOBALS['language'];
  }
}

/**
 * Get language selector form element
 */
function i18n_element_language_select($default = LANGUAGE_NONE) {
  if (is_object($default) || is_array($default)) {
    $default = i18n_object_langcode($default, LANGUAGE_NONE);
  }
  return array(
    '#type' => 'select',
    '#title' => t('Language'),
    '#default_value' => $default,
    '#options' => array(LANGUAGE_NONE => t('Language neutral')) + i18n_language_list(),
  );
}

/**
 * Get language field for hook_field_extra_fields()
 */
function i18n_language_field_extra() {
  return array(
    'form' => array(
      'language' => array(
        'label' => t('Language'),
        'description' => t('Language selection'),
        'weight' => 0,
      ),
    ),
    'display' => array(
      'language' => array(
        'label' => t('Language'),
        'description' => t('Language'),
        'weight' => 0,
      ),
    ),
  );
}

/**
 * Get full language list
 *
 * @todo See about creating a permission for seeing disabled languages
 */
function i18n_language_list($field = 'name', $mode = NULL) {
  $mode = isset($mode) ? $mode : variable_get('i18n_language_list', I18N_LANGUAGE_ENABLED);
  return locale_language_list($field, I18N_LANGUAGE_EXTENDED & $mode);
}

/**
 * Get language name for any defined (enabled or not) language
 *
 * @see locale_language_list()
 */
function i18n_language_name($lang) {
  $list = &drupal_static(__FUNCTION__);
  if (!isset($list)) {
    $list = locale_language_list('name', TRUE);
  }
  if (!$lang || $lang === LANGUAGE_NONE) {
    return t('Undefined');
  }
  elseif (isset($list[$lang])) {
    return check_plain($list[$lang]);
  }
  else {
    return t('Unknown');
  }
}

/**
 * Get valid language code for current page or check whether the code is a defined language
 */
function i18n_langcode($langcode = NULL) {
  return $langcode && $langcode !== LANGUAGE_NONE ? $langcode : i18n_language()->language;
}

/**
 * Implements hook_help().
 */
function i18n_help($path = 'admin/help#i18n', $arg) {
  switch ($path) {
    case 'admin/help#i18n' :
      $output = '<p>' . t('This module improves support for multilingual content in Drupal sites:') . '</p>';
      $output .= '<ul>';
      $output .= '<li>' . t('Shows content depending on page language.') . '</li>';
      $output .= '<li>' . t('Handles multilingual variables.') . '</li>';
      $output .= '<li>' . t('Extended language option for chosen content types. For these content types transations will be allowed for all defined languages, not only for enabled ones.') . '</li>';
      $output .= '<li>' . t('Provides a block for language selection and two theme functions: <em>i18n_flags</em> and <em>i18n_links</em>.') . '</li>';
      $output .= '</ul>';
      $output .= '<p>' . t('This is the base module for several others adding different features:') . '</p>';
      $output .= '<ul>';
      $output .= '<li>' . t('Multilingual menu items.') . '</li>';
      $output .= '<li>' . t('Multilingual taxonomy adds a language field for taxonomy vocabularies and terms.') . '</li>';
      $output .= '</ul>';
      $output .= '<p>' . t('For more information, see the online handbook entry for <a href="@i18n">Internationalization module</a>.', array('@i18n' => 'http://drupal.org/node/133977')) . '</p>';
      return $output;

    case 'admin/config/language/i18n':
      $output = '<ul>';
      $output .= '<li>' . t('To enable multilingual support for specific content types go to <a href="@configure_content_types">configure content types</a>.', array('@configure_content_types' => url('admin/structure/types'))) . '</li>';
      $output .= '</ul>';
      return $output;
  }
}

/**
 * Implements hook_menu().
 */
function i18n_menu() {
  $items['admin/config/regional/i18n'] = array(
    'title' => 'Multilingual settings',
    'description' => 'Configure extended options for multilingual content and translations.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('variable_module_form', 'i18n'),
    'access arguments' => array('administer site configuration'),
    'weight' => 10,
  );
  $items['admin/config/regional/i18n/configure'] = array(
    'title' => 'Multilingual system',
    'description' => 'Configure extended options for multilingual content and translations.',
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  module_load_include('pages.inc', 'i18n');
  $items += i18n_page_menu_items();
  return $items;
}

/**
 * Simple i18n API
 */

/**
 * Switch select Mode on off if enabled
 *
 * Usage for disabling content selection for a while then return to previous state
 *
 *   // Disable selection, but store previous mode
 *   $previous = i18n_select(FALSE);
 *
 *   // Other code to be run without content selection here
 *   ..........................
 *
 *   // Return to previous mode
 *   i18n_select($previous);
 *
 * @param $value
 *   Optional, enable/disable selection: TRUE/FALSE
 * @return boolean
 *   Previous selection mode (TRUE/FALSE)
 */
function i18n_select($value = NULL) {
  static $mode = FALSE;

  if (isset($value)) {
    $previous = $mode;
    $mode = $value;
    return $previous;
  }
  else {
    return $mode;
  }
}

/**
 * Get language properties.
 *
 * @param $code
 *   Language code.
 * @param $property
 *   It may be 'name', 'native', 'ltr'...
 */
function i18n_language_property($code, $property) {
  $languages = language_list();
  return isset($languages[$code]->$property) ? $languages[$code]->$property : NULL;
}

/**
 * Implements hook_preprocess_html().
 */
function i18n_preprocess_html(&$variables) {
  global $language;
  $variables['classes_array'][] = 'i18n-' . $language->language;
}

/**
 * Translate or update user defined string. Entry point for i18n_string API if enabled.
 *
 * This function is from i18n_string sub module and is subject to be moved back.
 *
 * @param $name
 *   Textgroup and context glued with ':'.
 * @param $default
 *   String in default language. Default language may or may not be English.
 * @param $options
 *   An associative array of additional options, with the following keys:
 *   - 'langcode' (defaults to the current language) The language code to translate to a language other than what is used to display the page.
 *   - 'filter' Filtering callback to apply to the translated string only
 *   - 'format' Input format to apply to the translated string only
 *   - 'callback' Callback to apply to the result (both to translated or untranslated string
 *   - 'update' (defaults to FALSE) Whether to update source table
 *   - 'translate' (defaults to TRUE) Whether to return a translation
 *
 * @return $string
 *   Translated string, $string if not found
 */
function i18n_string($name, $string, $options = array()) {
  $options += array('translate' => TRUE, 'update' => FALSE);
  if ($options['update']) {
    $result = function_exists('i18n_string_update') ? i18n_string_update($name, $string, $options) : FALSE;
  }
  if ($options['translate']) {
    $result = function_exists('i18n_string_translate') ? i18n_string_translate($name, $string, $options) : $string;
  }
  return $result;
}

/**
 * Get language from context.
 *
 * Depending on the page content we may need to use a different language for some operations.
 */
function i18n_context_language() {
  // Get language from the first module that provides it
  foreach (module_implements('i18n_context_language') as $module) {
    if ($language = module_invoke($module, 'i18n_context_language')) {
      return $language;
    }
  }
  return i18n_language();
}

/**
 * Create object wrapper
 */
function i18n_object($type, $object) {
  $i18n_object = &drupal_static(__FUNCTION__);
  $key = i18n_object_key($type, $object);
  $key = is_array($key) ? implode(':', $key) : $key;
  if (!isset($i18n_object[$type][$key])) {
    $class = i18n_object_info($type, 'class');
    if (!$class) {
      $class = module_exists('i18n_string') ? 'i18n_string_object_wrapper' : 'i18n_object_wrapper';
    }
    $i18n_object[$type][$key] = new $class($type, $object);
  }
  return $i18n_object[$type][$key];
}

/**
 * Get object language code
 *
 * @param $object
 *   Object or array having language field or plain language field
 * @param $default
 *   What value to return if the object doesn't have a valid language
 */
function i18n_object_langcode($object, $default = FALSE, $field = 'language') {
  $value = i18n_object_field($object, $field, $default);
  return $value && $value != LANGUAGE_NONE ? $value : $default;
}

/**
 * Get translation information for objects
 */
function i18n_object_info($type = NULL, $property = NULL, $default = NULL) {
  $info = &drupal_static(__FUNCTION__);
  if (!$info) {
    $info = module_invoke_all('i18n_object_info');
    drupal_alter('i18n_object_info', $info);
  }
  if ($property) {
    return isset($info[$type][$property]) ? $info[$type][$property] : $default;
  }
  elseif ($type) {
    return isset($info[$type]) ? $info[$type] : array();
  }
  else {
    return $info;
  }
}

/**
 * Get field value from object/array
 */
function i18n_object_field($object, $field, $default = NULL) {
  if (is_array($field)) {
    // We can handle a list of fields too. This is useful for multiple keys (like blocks)
    foreach ($field as $key => $name) {
      $values[$key] = i18n_object_field($object, $name);
    }
    return $values;
  }
  elseif (is_object($object)) {
    return isset($object->$field) ? $object->$field : $default;
  }
  elseif (is_array($object)) {
    return isset($object[$field]) ? $object[$field] : $default;
  }
  else {
    return $default;
  }
}

/**
 * Get key value from object/array
 */
function i18n_object_key($type, $object, $default = NULL) {
  if ($field = i18n_object_info($type, 'key')) {
    return i18n_object_field($object, $field, $default);
  }
  else {
    return $default;
  }
}

/**
 * Menu access callback for mixed translation tab
 */
function i18n_object_translate_access($type, $object) {
  return i18n_object($type, $object)->get_translate_access();
}

/**
 * Build translation link
 */
function i18n_translation_link($path, $langcode, $link = array()) {
  $language = i18n_language($langcode);
  $link += array(
    'href' => $path,
    'title' => $language->native,
    'language' => $language,
    'i18n_translation' => TRUE,
  );
  $link['attributes']['class'] = array('language-link');
  // @todo Fix languageicons weight, but until that
  if (function_exists('languageicons_link_add')) {
    languageicons_link_add($link);
  }
  return $link;
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function i18n_form_block_admin_display_form_alter(&$form, &$form_state) {
  $form['#submit'][] = 'i18n_form_block_admin_display_form_submit';
}

/**
 * Display a help message when enabling the language switcher block.
 */
function i18n_form_block_admin_display_form_submit($form, &$form_state) {
  foreach ($form_state['values']['blocks'] as $key => $block) {
    $previous = $form['blocks'][$key]['region']['#default_value'];
    if (empty($previous) && $block['region'] != -1 && $block['module'] == 'locale') {
      $message = t('The language switcher will appear only after configuring <a href="!url">language detection</a>. You need to enable at least one method that alters URLs like <em>URL</em> or <em>Session</em>.', array('!url' => url('admin/config/regional/language/configure')));
      drupal_set_message($message, 'warning', FALSE);
      break;
    }
  }
}

/**
 * Normal path should be checked with menu item's language to avoid
 * troubles when a node and it's translation has the same url alias.
 */
function i18n_prepare_normal_path($link_path, $language) {
  $normal_path = drupal_get_normal_path($link_path, $language);
  if ($link_path != $normal_path) {
    drupal_set_message(t('The menu system stores system paths only, but will use the URL alias for display. %link_path has been stored as %normal_path', array('%link_path' => $link_path, '%normal_path' => $normal_path)));
  }
  return $normal_path;
}

/**
 * Checks if an entity translation is enabled for the given entity type.
 * @param $entity_type
 */
function i18n_entity_translation_enabled($entity_type) {
  $cache = &drupal_static(__FUNCTION__);
  if (!isset($cache[$entity_type])) {
    // Check if the entity_translation module exists and if so if the given
    // entity type is handled.
    $cache[$entity_type] = module_exists('entity_translation') && entity_translation_enabled($entity_type);
  }
  return $cache[$entity_type];
}