modules/locale/locale.module

<?php
// $Id: locale.module,v 1.266 2009/10/23 22:24:16 webchick Exp $

/**
 * @file
 *   Add language handling functionality and enables the translation of the
 *   user interface to languages other than English.
 *
 *   When enabled, multiple languages can be set up. The site interface
 *   can be displayed in different languages, as well as nodes can have languages
 *   assigned. The setup of languages and translations is completely web based.
 *   Gettext portable object files are supported.
 */

/**
 * The language is determined using a URL language indicator:
 * path prefix or domain according to the configuration.
 */
define('LOCALE_LANGUAGE_NEGOTIATION_URL', 'locale-url');

/**
 * The language is set based on the browser language settings.
 */
define('LOCALE_LANGUAGE_NEGOTIATION_BROWSER', 'locale-browser');

/**
 * The language is determined using the current content language.
 */
define('LOCALE_LANGUAGE_NEGOTIATION_CONTENT', 'locale-content');

/**
 * The language is set based on the user language settings.
 */
define('LOCALE_LANGUAGE_NEGOTIATION_USER', 'locale-user');

/**
 * The language is set based on the request/session parameters.
 */
define('LOCALE_LANGUAGE_NEGOTIATION_SESSION', 'locale-session');

// ---------------------------------------------------------------------------------
// Hook implementations

/**
 * Implement hook_help().
 */
function locale_help($path, $arg) {
  switch ($path) {
    case 'admin/help#locale':
      $output = '<p>' . t('The locale module allows your Drupal site to be presented in languages other than the default English, a defining feature of multi-lingual websites. The locale module works by examining text as it is about to be displayed: when a translation of the text is available in the language to be displayed, the translation is displayed rather than the original text. When a translation is unavailable, the original text is displayed, and then stored for later review by a translator.') . '</p>';
      $output .= '<p>' . t('Beyond translation of the Drupal interface, the locale module provides a feature set tailored to the needs of a multi-lingual site. Language negotiation allows your site to automatically change language based on the domain or path used for each request. Users may (optionally) select their preferred language on their <em>My account</em> page, and your site can be configured to honor a web browser\'s preferred language settings. Your site content can be created in (and translated to) any enabled language, and each post may have a language-appropriate alias for each of its translations. The locale module works in concert with the <a href="@content-help">content translation module</a> to manage translated content.', array('@content-help' => url('admin/help/translation'))) . '</p>';
      $output .= '<p>' . t('Translations may be provided by:') . '</p>';
      $output .= '<ul><li>' . t("translating the original text via the locale module's integrated web interface, or") . '</li>';
      $output .= '<li>' . t('importing files from a set of existing translations, known as a translation package. A translation package enables the display of a specific version of Drupal in a specific language, and contain files in the Gettext Portable Object (<em>.po</em>) format. Although not all languages are available for every version of Drupal, translation packages for many languages are available for download from the <a href="@translations">Drupal translation page</a>.', array('@translations' => 'http://drupal.org/project/translations')) . '</li></ul>';
      $output .= '<p>' . t('If an existing translation package does not meet your needs, the Gettext Portable Object (<em>.po</em>) files within a package may be modified, or new <em>.po</em> files may be created, using a desktop Gettext editor. The locale module\'s <a href="@import">import</a> feature allows the translated strings from a new or modified <em>.po</em> file to be added to your site. The locale module\'s <a href="@export">export</a> feature generates files from your site\'s translated strings, that can either be shared with others or edited offline by a Gettext translation editor.', array('@import' => url('admin/config/regional/translate/import'), '@export' => url('admin/config/regional/translate/export'))) . '</p>';
      $output .= '<p>' . t('For more information, see the online handbook entry for <a href="@locale">Locale module</a>.', array('@locale' => 'http://drupal.org/handbook/modules/locale/')) . '</p>';
      return $output;
    case 'admin/config/regional/language':
      $output = '<p>' . t("This page provides an overview of your site's enabled languages. If multiple languages are available and enabled, the text on your site interface may be translated, registered users may select their preferred language on the <em>My account</em> page, and site authors may indicate a specific language when creating posts. Languages will be displayed in the order you specify in places such as the language switcher block, or the language dropdown when creating or editing posts. The site's default language is used for anonymous visitors and for users who have not selected a preferred language.") . '</p>';
      $output .= '<p>' . t('For each language available on the site, use the <em>edit</em> link to configure language details, including name, an optional language-specific path or domain, and whether the language is natively presented either left-to-right or right-to-left. These languages also appear in the <em>Language</em> selection when creating a post of a content type with multilingual support.') . '</p>';
      $output .= '<p>' . t('Use the <a href="@add-language">add language page</a> to enable additional languages (and automatically import files from a translation package, if available), the <a href="@search">translate interface page</a> to locate strings for manual translation, or the <a href="@import">import page</a> to add translations from individual <em>.po</em> files. A number of contributed translation packages containing <em>.po</em> files are available on the <a href="@translations">Drupal.org translations page</a>.', array('@add-language' => url('admin/config/regional/language/add'), '@search' => url('admin/config/regional/translate/translate'), '@import' => url('admin/config/regional/translate/import'), '@translations' => 'http://drupal.org/project/translations')) . '</p>';
      $output .= '<p>' . t('Remember that your changes will not be saved until you click the <em>Save configuration</em> button at the bottom of the page.') . '</p>';
      return $output;
    case 'admin/config/regional/language/add':
      return '<p>' . t('Add all languages to be supported by your site. If your desired language is not available in the <em>Language name</em> drop-down, click <em>Custom language</em> and provide a language code and other details manually. When providing a language code manually, be sure to enter a standardized language code, since this code may be used by browsers to determine an appropriate display language.') . '</p>';
    case 'admin/config/regional/language/configure':
      $output = '<p>' . t("Language negotiation settings determine the site's content and presentation languages. For both <em>language types</em> there is a list of <em>language detection methods</em> which can be used to configure the desired language negotiation logic. Each detection method can be <em>dragged</em> to gain a higher priority, but it must be <em>enabled</em> to affect the language negotiation process. If a language detection method is applied then all the lower ones are <em>ignored</em>, otherwise the following one will be taken into account. Some lanaguage detection methods provide a configuration page to further specify their behavior. The <em>default</em> detection method is always applied, so anything below it is always ignored. <strong>Modifying this setting may break all incoming URLs and should be used with caution in a production environment.</strong>") . '</p>';
      $output .= '<p>' . t('Available options include:') .'</p>';
      $output .= '<ul><li>' . t('<strong>URL.</strong> The language is determined by examining the URL for a language code, a custom string, or a domain, that matches the ones (if any) specified for each language. The path prefix or domain name for a language may be set by editing the <a href="@languages">available languages</a>. In the absence of an appropriate match, the site is displayed in the <a href="@languages">default language</a>. A configuration is available to choose whether use the path prefix or the domain. <em>Example: "example.com/de/contact" sets language to German based on the use of "de" within the path. "http://de.example.com/contact" sets presentation language to German based on the use of "http://de.example.com" in the domain.</em>', array('@languages' => url('admin/config/regional/language'))) . '</li>';
      $output .= '<li>' . t('<strong>Session.</strong> The language is determined from a request/session parameter. A configuration is available to choose the URL parameter name to be used. <em>Example: "example.com?language=de" sets language to German based on the use of "de" within the "language" parameter.</em>') . '</li></ul>';
      return $output;
    case 'admin/config/regional/translate':
      $output = '<p>' . t('This page provides an overview of available translatable strings. Drupal displays translatable strings in text groups; modules may define additional text groups containing other translatable strings. Because text groups provide a method of grouping related strings, they are often used to focus translation efforts on specific areas of the Drupal interface.') . '</p>';
      $output .= '<p>' . t('Review the <a href="@languages">languages page</a> for more information on adding support for additional languages.', array('@languages' => url('admin/config/regional/language'))) . '</p>';
      return $output;
    case 'admin/config/regional/translate/import':
      $output = '<p>' . t('This page imports the translated strings contained in an individual Gettext Portable Object (<em>.po</em>) file. Normally distributed as part of a translation package (each translation package may contain several <em>.po</em> files), a <em>.po</em> file may need to be imported after offline editing in a Gettext translation editor. Importing an individual <em>.po</em> file may be a lengthy process.') . '</p>';
      $output .= '<p>' . t('Note that the <em>.po</em> files within a translation package are imported automatically (if available) when new modules or themes are enabled, or as new languages are added. Since this page only allows the import of one <em>.po</em> file at a time, it may be simpler to download and extract a translation package into your Drupal installation directory and <a href="@language-add">add the language</a> (which automatically imports all <em>.po</em> files within the package). Translation packages are available for download on the <a href="@translations">Drupal translation page</a>.', array('@language-add' => url('admin/config/regional/language/add'), '@translations' => 'http://drupal.org/project/translations')) . '</p>';
      return $output;
    case 'admin/config/regional/translate/export':
      return '<p>' . t('This page exports the translated strings used by your site. An export file may be in Gettext Portable Object (<em>.po</em>) form, which includes both the original string and the translation (used to share translations with others), or in Gettext Portable Object Template (<em>.pot</em>) form, which includes the original strings only (used to create new translations with a Gettext translation editor).') . '</p>';
    case 'admin/config/regional/translate/translate':
      return '<p>' . t('This page allows a translator to search for specific translated and untranslated strings, and is used when creating or editing translations. (Note: For translation tasks involving many strings, it may be more convenient to <a href="@export">export</a> strings for offline editing in a desktop Gettext translation editor.) Searches may be limited to strings found within a specific text group or in a specific language.', array('@export' => url('admin/config/regional/translate/export'))) . '</p>';
    case 'admin/structure/block/manage':
      if ($arg[4] == 'locale' && $arg[5] == 0) {
        return '<p>' . t('This block is only shown if <a href="@languages">at least two languages are enabled</a> and <a href="@configuration">language negotiation</a> is set to something other than <em>None</em>.', array('@languages' => url('admin/config/regional/language'), '@configuration' => url('admin/config/regional/language/configure'))) . '</p>';
      }
      break;
  }
}

/**
 * Implement hook_menu().
 */
function locale_menu() {
  // Manage languages
  $items['admin/config/regional/language'] = array(
    'title' => 'Languages',
    'description' => 'Configure languages for content and the user interface.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_languages_overview_form'),
    'access arguments' => array('administer languages'),
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/language/overview'] = array(
    'title' => 'List',
    'weight' => 0,
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['admin/config/regional/language/add'] = array(
    'title' => 'Add language',
    'page callback' => 'locale_languages_add_screen', // two forms concatenated
    'access arguments' => array('administer languages'),
    'weight' => 5,
    'type' => MENU_LOCAL_ACTION,
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/language/configure'] = array(
    'title' => 'Configure',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_languages_configure_form'),
    'access arguments' => array('administer languages'),
    'weight' => 10,
    'file' => 'locale.inc',
    'file path' => 'includes',
    'type' => MENU_LOCAL_TASK,
  );
  $items['admin/config/regional/language/configure/url'] = array(
    'title' => 'URL language provider configuration',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_language_providers_url_form'),
    'access arguments' => array('administer languages'),
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/language/configure/session'] = array(
    'title' => 'Session language provider configuration',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_language_providers_session_form'),
    'access arguments' => array('administer languages'),
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/language/edit/%'] = array(
    'title' => 'Edit language',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_languages_edit_form', 5),
    'access arguments' => array('administer languages'),
    'file' => 'locale.inc',
    'file path' => 'includes',
    'type' => MENU_CALLBACK,
  );
  $items['admin/config/regional/language/delete/%'] = array(
    'title' => 'Confirm',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_languages_delete_form', 5),
    'access arguments' => array('administer languages'),
    'file' => 'locale.inc',
    'file path' => 'includes',
    'type' => MENU_CALLBACK,
  );

  // Translation functionality
  $items['admin/config/regional/translate'] = array(
    'title' => 'Translate interface',
    'description' => 'Translate the built in interface and optionally other text.',
    'page callback' => 'locale_inc_callback',
    'page arguments' => array('locale_translate_overview_screen'), // not a form, just a table
    'access arguments' => array('translate interface'),
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/translate/overview'] = array(
    'title' => 'Overview',
    'weight' => 0,
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['admin/config/regional/translate/translate'] = array(
    'title' => 'Translate',
    'weight' => 10,
    'type' => MENU_LOCAL_TASK,
    'page callback' => 'locale_translate_seek_screen', // search results and form concatenated
    'access arguments' => array('translate interface'),
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/translate/import'] = array(
    'title' => 'Import',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_translate_import_form'),
    'access arguments' => array('translate interface'),
    'weight' => 20,
    'type' => MENU_LOCAL_TASK,
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/translate/export'] = array(
    'title' => 'Export',
    'page callback' => 'locale_translate_export_screen',  // possibly multiple forms concatenated
    'access arguments' => array('translate interface'),
    'weight' => 30,
    'type' => MENU_LOCAL_TASK,
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/translate/edit/%'] = array(
    'title' => 'Edit string',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_translate_edit_form', 5),
    'access arguments' => array('translate interface'),
    'type' => MENU_CALLBACK,
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/translate/delete/%'] = array(
    'title' => 'Delete string',
    'page callback' => 'locale_translate_delete_page',
    'page arguments' => array(5),
    'access arguments' => array('translate interface'),
    'type' => MENU_CALLBACK,
    'file' => 'locale.inc',
    'file path' => 'includes',
  );

  // Localize date formats.
  $items['admin/config/regional/date-time/locale'] = array(
    'title' => 'Localize',
    'description' => 'Configure date formats for each locale',
    'page callback' => 'locale_date_format_language_overview_page',
    'access arguments' => array('administer site configuration'),
    'type' => MENU_LOCAL_TASK,
    'weight' => -8,
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/date-time/locale/%/edit'] = array(
    'title' => 'Localize date formats',
    'description' => 'Configure date formats for each locale',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_date_format_form', 5),
    'access arguments' => array('administer site configuration'),
    'type' => MENU_CALLBACK,
    'file' => 'locale.inc',
    'file path' => 'includes',
  );
  $items['admin/config/regional/date-time/locale/%/reset'] = array(
    'title' => 'Reset date formats',
    'description' => 'Reset localized date formats to global defaults',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_date_format_reset_form', 5),
    'access arguments' => array('administer site configuration'),
    'type' => MENU_CALLBACK,
    'file' => 'locale.inc',
    'file path' => 'includes',
  );

  return $items;
}

/**
 * Implements hook_init().
 *
 * Initialize date formats according to the user's current locale.
 */
function locale_init() {
  global $conf, $language;
  include_once DRUPAL_ROOT . '/includes/locale.inc';

  // For each date type (e.g. long, short), get the localized date format
  // for the user's current language and override the default setting for it
  // in $conf. This should happen on all pages except the date and time formats
  // settings page, where we want to display the site default and not the
  // localized version.
  if (strpos($_GET['q'], 'admin/config/regional/date-time/formats') !== 0) {
    $languages = array($language->language);

    // Setup appropriate date formats for this locale.
    $formats = locale_get_localized_date_format($languages);
    foreach ($formats as $format_type => $format) {
      $conf[$format_type] = $format;
    }
  }
}

/**
 * Wrapper function to be able to set callbacks in locale.inc
 */
function locale_inc_callback() {
  $args = func_get_args();
  $function = array_shift($args);
  include_once DRUPAL_ROOT . '/includes/locale.inc';
  return call_user_func_array($function, $args);
}

/**
 * Implement hook_permission().
 */
function locale_permission() {
  return array(
    'administer languages' => array(
      'title' => t('Administer languages'),
      'description' => t('Manage the languages in which the website content and interface text may be displayed.'),
    ),
    'translate interface' => array(
      'title' => t('Translate the interface'),
      'description' => t('Translate the text of the website interface.'),
    ),
  );
}

/**
 * Implement hook_locale().
 */
function locale_locale($op = 'groups') {
  switch ($op) {
    case 'groups':
      return array('default' => t('Built-in interface'));
  }
}

/**
 * Form builder callback to display language selection widget.
 *
 * @ingroup forms
 * @see locale_form_alter()
 */
function locale_language_selector_form(&$form, &$form_state, $user) {
  global $language;
  $languages = language_list('enabled');
  $languages = $languages[1];

  // If the user is being created, we set the user language to the page language.
  $user_preferred_language = $user->uid ? user_preferred_language($user) : $language;

  $names = array();
  foreach ($languages as $langcode => $item) {
    $name = t($item->name);
    $names[$langcode] = $name . ($item->native != $name ? ' (' . $item->native . ')' : '');
  }
  $form['locale'] = array(
    '#type' => 'fieldset',
    '#title' => t('Language settings'),
    '#weight' => 1,
  );

  // Get language negotiation settings.
  $mode = language_negotiation_get(LANGUAGE_TYPE_INTERFACE) != LANGUAGE_NEGOTIATION_DEFAULT;
  $form['locale']['language'] = array(
    '#type' => (count($names) <= 5 ? 'radios' : 'select'),
    '#title' => t('Language'),
    '#default_value' => $user_preferred_language->language,
    '#options' => $names,
    '#description' => $mode ? t("This account's default language for e-mails, and preferred language for site presentation.") : t("This account's default language for e-mails."),
  );
}

/**
 * Implement hook_form_FORM_ID_alter().
 */
function locale_form_path_admin_form_alter(&$form, &$form_state) {
  $form['language'] = array(
    '#type' => 'select',
    '#title' => t('Language'),
    '#options' => array('' => t('All languages')) + locale_language_list('name'),
    '#default_value' => $form['language']['#value'],
    '#weight' => -10,
    '#description' => t('A path alias set for a specific language will always be used when displaying this page in that language, and takes precedence over path aliases set for <em>All languages</em>.'),
  );
}

/**
 * Implement hook_form_FORM_ID_alter().
 */
function locale_form_node_type_form_alter(&$form, &$form_state) {
  if (isset($form['identity']['type'])) {
    $form['workflow']['language_content_type'] = array(
      '#type' => 'radios',
      '#title' => t('Multilingual support'),
      '#default_value' => variable_get('language_content_type_' . $form['#node_type']->type, 0),
      '#options' => array(t('Disabled'), t('Enabled')),
      '#description' => t('Enable multilingual support for this content type. If enabled, a language selection field will be added to the editing form, allowing you to select from one of the <a href="!languages">enabled languages</a>. If disabled, new posts are saved with the default language. Existing content will not be affected by changing this option.', array('!languages' => url('admin/config/regional/language'))),
    );
  }
}

/**
 * Return whether the given content type has multilingual support.
 *
 * @return
 *   True if multilingual support is enabled.
 */
function locale_multilingual_node_type($type_name) {
  return (bool) variable_get('language_content_type_' . $type_name, 0);
}

/**
 * Implement hook_form_alter().
 *
 * Adds language fields to forms.
 */
function locale_form_alter(&$form, &$form_state, $form_id) {
  // Only alter user forms if there is more than one language.
  if (drupal_multilingual()) {
    // Display language selector when either creating a user on the admin
    // interface or editing a user account.
    if (($form_id == 'user_register_form' && user_access('administer users')) || ($form_id == 'user_profile_form' && $form['#user_category'] == 'account')) {
      locale_language_selector_form($form, $form_state, $form['#user']);
    }
  }
  if (isset($form['#id']) && $form['#id'] == 'node-form') {
    if (isset($form['#node']->type) && locale_multilingual_node_type($form['#node']->type)) {
      $form['language'] = array(
        '#type' => 'select',
        '#title' => t('Language'),
        '#default_value' => (isset($form['#node']->language) ? $form['#node']->language : ''),
        '#options' => array('' => t('Language neutral')) + locale_language_list('name'),
      );
    }
    // Node type without language selector: assign the default for new nodes
    elseif (!isset($form['#node']->nid)) {
      $default = language_default();
      $form['language'] = array(
        '#type' => 'value',
        '#value' => $default->language
      );
    }
    $form['#submit'][] = 'locale_field_node_form_submit';
  }
}

/**
 * Form submit handler for node_form().
 *
 * Check if Locale is registered as a translation handler and handle possible
 * node language changes.
 */
function locale_field_node_form_submit($form, &$form_state) {
  if (field_multilingual_check_translation_handlers('node', 'locale')) {
    module_load_include('inc', 'locale', 'locale.field');
    locale_field_node_form_update_field_language($form, $form_state);
  }
}

/**
 * Implement hook_theme().
 */
function locale_theme() {
  return array(
    'locale_languages_overview_form' => array(
      'render element' => 'form',
    ),
    'locale_languages_configure_form' => array(
      'render element' => 'form',
    ),
    'locale_translation_filters' => array(
      'render element' => 'form',
    ),
    'locale_date_format_form' => array(
      'render element' => 'form',
    ),
  );
}

/**
 * Implement hook_field_attach_view_alter().
 */
function locale_field_attach_view_alter(&$output, $context) {
  // In locale_field_fallback_view() we might call field_attach_view(). The
  // static variable avoids unnecessary recursion. 
  static $recursion;

  // Do not apply fallback rules if disabled or if Locale is not registered as a
  // translation handler.
  if (!$recursion && variable_get('locale_field_fallback_view', TRUE) && field_multilingual_check_translation_handlers($context['obj_type'], 'locale')) {
    $recursion = TRUE;
    module_load_include('inc', 'locale', 'locale.field');
    locale_field_fallback_view($output, $context);
    $recursion = FALSE;
  }
}

/**
 * Implement hook_entity_info_alter().
 */
function locale_entity_info_alter(&$entity_info) {
  $enabled = drupal_multilingual();
  foreach ($entity_info as $type => $info) {
    $entity_info[$type]['translation']['locale'] = $enabled;
  }
}

/**
 * Implement hook_language_types_info().
 */
function locale_language_types_info() {
  return array(
    LANGUAGE_TYPE_CONTENT => array(
      'name' => t('Content'),
      'description' => t('If a piece of content is available in multiple languages, the one matching the <em>content</em> language will be used.'),
    ),
    LANGUAGE_TYPE_INTERFACE => array(
      'name' => t('Interface'),
      'description' => t('The interface labels will be displayed in the <em>interface</em> language.'),
    ),
    LANGUAGE_TYPE_URL => array(
      'fixed' => array(LOCALE_LANGUAGE_NEGOTIATION_URL),
    ),
  );
}

/**
 * Implement hook_language_negotiation_info().
 */
function locale_language_negotiation_info() {
  $file = 'includes/locale.inc';
  $providers = array();

  $providers[LOCALE_LANGUAGE_NEGOTIATION_URL] = array(
    'types' => array(LANGUAGE_TYPE_CONTENT, LANGUAGE_TYPE_INTERFACE, LANGUAGE_TYPE_URL),
    'callbacks' => array(
      'language' => 'locale_language_from_url',
      'switcher' => 'locale_language_switcher_url',
      'url_rewrite' => 'locale_language_url_rewrite_url',
    ),
    'file' => $file,
    'weight' => -8,
    'name' => t('URL'),
    'description' => t('The language is determined from the URL (Path prefix or domain).'),
    'config' => 'admin/config/regional/language/configure/url',
  );

  $providers[LOCALE_LANGUAGE_NEGOTIATION_SESSION] = array(
    'callbacks' => array(
      'language' => 'locale_language_from_session',
      'switcher' => 'locale_language_switcher_session',
      'url_rewrite' => 'locale_language_url_rewrite_session',
    ),
    'file' => $file,
    'weight' => -6,
    'name' => t('Session'),
    'description' => t('The language is determined from a request/session parameter.'),
    'config' => 'admin/config/regional/language/configure/session',
  );

  $providers[LOCALE_LANGUAGE_NEGOTIATION_USER] = array(
    'callbacks' => array('language' => 'locale_language_from_user'),
    'file' => $file,
    'weight' => -4,
    'name' => t('User'),
    'description' => t('The language is determined from the language preference set in the user account.'),
  );

  $providers[LOCALE_LANGUAGE_NEGOTIATION_BROWSER] = array(
    'callbacks' => array('language' => 'locale_language_from_browser'),
    'name' => $file,
    'weight' => -2,
    'cache' => CACHE_DISABLED,
    'name' => t('Browser'),
    'description' => t('The language is determined from the browser\'s language settings.'),
  );

  $providers[LOCALE_LANGUAGE_NEGOTIATION_CONTENT] = array(
    'types' => array(LANGUAGE_TYPE_INTERFACE),
    'callbacks' => array('language' => 'locale_language_from_content'),
    'file' => $file,
    'weight' => 8,
    'name' => t('Content'),
    'description' => t('The interface language is the same as the negotiated content language.'),
  );

  return $providers;
}

// ---------------------------------------------------------------------------------
// Locale core functionality

/**
 * Provides interface translation services.
 *
 * This function is called from t() to translate a string if needed.
 *
 * @param $string
 *   A string to look up translation for. If omitted, all the
 *   cached strings will be returned in all languages already
 *   used on the page.
 * @param $context
 *   The context of this string.
 * @param $langcode
 *   Language code to use for the lookup.
 * @param $reset
 *   Set to TRUE to reset the in-memory cache.
 */
function locale($string = NULL, $context = NULL, $langcode = NULL, $reset = FALSE) {
  global $language;
  static $locale_t;

  if ($reset) {
    // Reset in-memory cache.
    $locale_t = NULL;
  }

  if (!isset($string)) {
    // Return all cached strings if no string was specified
    return $locale_t;
  }

  $langcode = isset($langcode) ? $langcode : $language->language;

  // Store database cached translations in a static var.
  if (!isset($locale_t[$langcode])) {
    $locale_t[$langcode] = array();
    // Disabling the usage of string caching allows a module to watch for
    // the exact list of strings used on a page. From a performance
    // perspective that is a really bad idea, so we have no user
    // interface for this. Be careful when turning this option off!
    if (variable_get('locale_cache_strings', 1) == 1) {
      if ($cache = cache_get('locale:' . $langcode, 'cache')) {
        $locale_t[$langcode] = $cache->data;
      }
      elseif (lock_acquire('locale_cache_' . $langcode)) {
        // Refresh database stored cache of translations for given language.
        // We only store short strings used in current version, to improve
        // performance and consume less memory.
        $result = db_query("SELECT s.source, s.context, t.translation, t.language FROM {locales_source} s LEFT JOIN {locales_target} t ON s.lid = t.lid AND t.language = :language WHERE s.textgroup = 'default' AND s.version = :version AND LENGTH(s.source) < 75", array(':language' => $langcode, ':version' => VERSION));
        foreach ($result as $data) {
          $locale_t[$langcode][$data->context][$data->source] = (empty($data->translation) ? TRUE : $data->translation);
        }
        cache_set('locale:' . $langcode, $locale_t[$langcode]);
        lock_release('locale_cache_' . $langcode);
      }
    }
  }

  // If we have the translation cached, skip checking the database
  if (!isset($locale_t[$langcode][$context][$string])) {

    // We do not have this translation cached, so get it from the DB.
    $translation = db_query("SELECT s.lid, t.translation, s.version FROM {locales_source} s LEFT JOIN {locales_target} t ON s.lid = t.lid AND t.language = :language WHERE s.source = :source AND s.context = :context AND s.textgroup = 'default'", array(
      ':language' => $langcode,
      ':source' => $string,
      ':context' => (string) $context,
    ))->fetchObject();
    if ($translation) {
      // We have the source string at least.
      // Cache translation string or TRUE if no translation exists.
      $locale_t[$langcode][$context][$string] = (empty($translation->translation) ? TRUE : $translation->translation);

      if ($translation->version != VERSION) {
        // This is the first use of this string under current Drupal version. Save version
        // and clear cache, to include the string into caching next time. Saved version is
        // also a string-history information for later pruning of the tables.
        db_update('locales_source')
          ->fields(array('version' => VERSION))
          ->condition('lid', $translation->lid)
          ->execute();
        cache_clear_all('locale:', 'cache', TRUE);
      }
    }
    else {
      // We don't have the source string, cache this as untranslated.
      db_insert('locales_source')
        ->fields(array(
          'location' => request_uri(),
          'source' => $string,
          'context' => (string) $context,
          'textgroup' => 'default',
          'version' => VERSION,
        ))
        ->execute();
      $locale_t[$langcode][$context][$string] = TRUE;
      // Clear locale cache so this string can be added in a later request.
      cache_clear_all('locale:', 'cache', TRUE);
    }
  }

  return ($locale_t[$langcode][$context][$string] === TRUE ? $string : $locale_t[$langcode][$context][$string]);
}

/**
 * Returns plural form index for a specific number.
 *
 * The index is computed from the formula of this language.
 *
 * @param $count
 *   Number to return plural for.
 * @param $langcode
 *   Optional language code to translate to a language other than
 *   what is used to display the page.
 */
function locale_get_plural($count, $langcode = NULL) {
  global $language;
  static $locale_formula, $plurals = array();

  $langcode = $langcode ? $langcode : $language->language;

  if (!isset($plurals[$langcode][$count])) {
    if (!isset($locale_formula)) {
      $language_list = language_list();
      $locale_formula[$langcode] = $language_list[$langcode]->formula;
    }
    if ($locale_formula[$langcode]) {
      $n = $count;
      $plurals[$langcode][$count] = @eval('return intval(' . $locale_formula[$langcode] . ');');
      return $plurals[$langcode][$count];
    }
    else {
      $plurals[$langcode][$count] = -1;
      return -1;
    }
  }
  return $plurals[$langcode][$count];
}


/**
 * Returns a language name
 */
function locale_language_name($lang) {
  static $list = NULL;
  if (!isset($list)) {
    $list = locale_language_list();
  }
  return ($lang && isset($list[$lang])) ? $list[$lang] : t('All');
}

/**
 * Returns array of language names
 *
 * @param $field
 *   'name' => names in current language, localized
 *   'native' => native names
 * @param $all
 *   Boolean to return all languages or only enabled ones
 */
function locale_language_list($field = 'name', $all = FALSE) {
  if ($all) {
    $languages = language_list();
  }
  else {
    $languages = language_list('enabled');
    $languages = $languages[1];
  }
  $list = array();
  foreach ($languages as $language) {
    $list[$language->language] = ($field == 'name') ? t($language->name) : $language->$field;
  }
  return $list;
}

/**
 * Imports translations when new modules or themes are installed or enabled.
 *
 * This function will either import translation for the component change
 * right away, or start a batch if more files need to be imported.
 *
 * @param $components
 *   An array of component (theme and/or module) names to import
 *   translations for.
 */
function locale_system_update($components) {
  include_once DRUPAL_ROOT . '/includes/locale.inc';
  if ($batch = locale_batch_by_component($components)) {
    batch_set($batch);
  }
}

/**
 * Implement hook_js_alter().
 *
 * This function checks all JavaScript files currently added via drupal_add_js()
 * and invokes parsing if they have not yet been parsed for Drupal.t()
 * and Drupal.formatPlural() calls. Also refreshes the JavaScript translation
 * file if necessary, and adds it to the page.
 */
function locale_js_alter(&$javascript) {
  global $language;

  $dir = 'public://' . variable_get('locale_js_directory', 'languages');
  $parsed = variable_get('javascript_parsed', array());
  $files = $new_files = FALSE;

  foreach ($javascript as $item) {
    if ($item['type'] == 'file') {
      $files = TRUE;
      $filepath = $item['data'];
      if (!in_array($filepath, $parsed)) {
        // Don't parse our own translations files.
        if (substr($filepath, 0, strlen($dir)) != $dir) {
          locale_inc_callback('_locale_parse_js_file', $filepath);
          watchdog('locale', 'Parsed JavaScript file %file.', array('%file' => $filepath));
          $parsed[] = $filepath;
          $new_files = TRUE;
        }
      }
    }
  }

  // If there are any new source files we parsed, invalidate existing
  // JavaScript translation files for all languages, adding the refresh
  // flags into the existing array.
  if ($new_files) {
    $parsed += locale_inc_callback('_locale_invalidate_js');
  }

  // If necessary, rebuild the translation file for the current language.
  if (!empty($parsed['refresh:' . $language->language])) {
    // Don't clear the refresh flag on failure, so that another try will
    // be performed later.
    if (locale_inc_callback('_locale_rebuild_js')) {
      unset($parsed['refresh:' . $language->language]);
    }
    // Store any changes after refresh was attempted.
    variable_set('javascript_parsed', $parsed);
  }
  // If no refresh was attempted, but we have new source files, we need
  // to store them too. This occurs if current page is in English.
  elseif ($new_files) {
    variable_set('javascript_parsed', $parsed);
  }

  // Add the translation JavaScript file to the page.
  if ($files && !empty($language->javascript)) {
    // Add the translation JavaScript file to the page.
    $file = $dir . '/' . $language->language . '_' . $language->javascript . '.js';
    $javascript[$file] = drupal_js_defaults($file);
  }
}

/*
 * Implement hook_css_alter().
 *
 * This function checks all CSS files currently added via drupal_add_css() and
 * and checks to see if a related right to left CSS file should be included.
 */
function locale_css_alter(&$css) {
  global $language;

  // If the current language is RTL, add the CSS file with the RTL overrides.
  if ($language->direction == LANGUAGE_RTL) {
    foreach ($css as $data => $item) {
      // Only provide RTL overrides for files.
      if ($item['type'] == 'file') {
        $rtl_path = str_replace('.css', '-rtl.css', $item['data']);
        if (file_exists($rtl_path) && !isset($css[$rtl_path])) {
          // Replicate the same item, but with the RTL path and a little larger
          // weight so that it appears directly after the original CSS file.
          $item['data'] = $rtl_path;
          $item['weight'] += 0.01;
          $css[$rtl_path] = $item;
        }
      }
    }
  }
}

// ---------------------------------------------------------------------------------
// Language switcher block

/**
 * Implement hook_block_info().
 */
function locale_block_info() {
  include_once DRUPAL_ROOT . '/includes/language.inc';
  $block = array();
  $info = language_types_info();
  foreach (language_types_configurable() as $type) {
    $block[$type] = array(
      'info' => t('Language switcher (@type)', array('@type' => $info[$type]['name'])),
      // Not worth caching.
      'cache' => DRUPAL_NO_CACHE,
    );
  }
  return $block;
}

/**
 * Implement hook_block_view().
 *
 * Displays a language switcher. Only show if we have at least two languages.
 */
function locale_block_view($type) {
  if (drupal_multilingual()) {
    $path = drupal_is_front_page() ? '<front>' : $_GET['q'];
    $links = language_negotiation_get_switch_links($type, $path);

    if (isset($links->links) && count($links->links > 1)) {
      $class = "language-switcher-{$links->provider}";
      $variables = array('links' => $links->links, 'attributes' => array('class' => array($class)));
      $block['content'] = theme('links', $variables);
      $block['subject'] = t('Languages');
      return $block;
    }
  }
}

/**
 * Theme locale translation filter selector.
 *
 * @ingroup themeable
 */
function theme_locale_translation_filters($variables) {
  $form = $variables['form'];
  $output = '';

  foreach (element_children($form['status']) as $key) {
    $output .= drupal_render($form['status'][$key]);
  }
  $output .= '<div id="locale-translation-buttons">' . drupal_render($form['buttons']) . '</div>';
  return $output;
}

/**
 * Theme locale date format form.
 *
 * @ingroup themeable
 */
function theme_locale_date_format_form($variables) {
  $form = $variables['form'];
  $header = array(
    t('Date type'),
    t('Format'),
  );

  foreach (element_children($form['date_formats']) as $key) {
    $row = array();
    $row[] = $form['date_formats'][$key]['#title'];
    unset($form['date_formats'][$key]['#title']);
    $row[] = array('data' => drupal_render($form['date_formats'][$key]));
    $rows[] = $row;
  }

  $output = drupal_render($form['language']);
  $output .= theme('table', array('header' => $header, 'rows' => $rows));
  $output .= drupal_render_children($form);

  return $output;
}

/**
 * Display edit date format links for each language.
 */
function locale_date_format_language_overview_page() {
  $header = array(
    t('Language'),
    array('data' => t('Operations'), 'colspan' => '2'),
  );

  // Get list of languages.
  $languages = locale_language_list('native');

  foreach ($languages as $langcode => $info) {
    $row = array();
    $row[] = $languages[$langcode];
    $row[] = l(t('edit'), 'admin/config/regional/date-time/locale/' . $langcode . '/edit');
    $row[] = l(t('reset'), 'admin/config/regional/date-time/locale/' . $langcode . '/reset');
    $rows[] = $row;
  }

  return theme('table', array('header' => $header, 'rows' => $rows));
}

/**
 * Provide date localization configuration options to users.
 */
function locale_date_format_form($form, &$form_state, $langcode) {
  $languages = locale_language_list('native');
  $language_name = $languages[$langcode];

  // Display the current language name.
  $form['language'] = array(
    '#type' => 'item',
    '#title' => t('Language'),
    '#markup' => check_plain($language_name),
    '#weight' => -10,
  );
  $form['langcode'] = array(
    '#type' => 'value',
    '#value' => $langcode,
  );

  // Get list of date format types.
  $types = system_get_date_types();

  // Get list of available formats.
  $formats = system_get_date_formats();
  $choices = array();
  foreach ($formats as $type => $list) {
    foreach ($list as $f => $format) {
      $choices[$f] = format_date(REQUEST_TIME, 'custom', $f);
    }
  }

  // Get configured formats for each language.
  $locale_formats = system_date_format_locale($langcode);
  // Display a form field for each format type.
  foreach ($types as $type => $type_info) {
    if (!empty($locale_formats) && in_array($type, array_keys($locale_formats))) {
      $default = $locale_formats[$type];
    }
    else {
      $default = variable_get('date_format_' . $type, array_shift(array_keys($formats)));
    }

    // Show date format select list.
    $form['date_formats']['date_format_' . $type] = array(
      '#type' => 'select',
      '#title' => check_plain($type_info['title']),
      '#attributes' => array('class' => array('date-format')),
      '#default_value' => (isset($choices[$default]) ? $default : 'custom'),
      '#options' => $choices,
    );
  }

  $form['buttons']['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save configuration'),
  );

  return $form;
}

/**
 * Submit handler for configuring localized date formats on the locale_date_format_form.
 */
function locale_date_format_form_submit($form, &$form_state) {
  include_once DRUPAL_ROOT . '/includes/locale.inc';
  $langcode = $form_state['values']['langcode'];

  // Get list of date format types.
  $types = system_get_date_types();
  foreach ($types as $type => $type_info) {
    $format = $form_state['values']['date_format_' . $type];
    if ($format == 'custom') {
      $format = $form_state['values']['date_format_' . $type . '_custom'];
    }
    locale_date_format_save($langcode, $type, $format);
  }
  drupal_set_message(t('Configuration saved.'));
  $form_state['redirect'] = 'admin/config/regional/date-time/locale';
}

/**
 * Reset locale specific date formats to the global defaults.
 *
 * @param $langcode
 *   Language code, e.g. 'en'.
 */
function locale_date_format_reset_form($form, &$form_state, $langcode) {
  $form['langcode'] = array('#type' => 'value', '#value' => $langcode);
  $languages = language_list();
  return confirm_form($form,
    t('Are you sure you want to reset the date formats for %language to the global defaults?', array('%language' => $languages[$langcode]->name)),
    'admin/config/regional/date-time/locale',
    t('Resetting will remove all localized date formats for this language. This action cannot be undone.'),
    t('Reset'), t('Cancel'));
}

/**
 * Reset date formats for a specific language to global defaults.
 */
function locale_date_format_reset_form_submit($form, &$form_state) {
  db_delete('date_format_locale')
    ->condition('language', $form_state['values']['langcode'])
    ->execute();
  $form_state['redirect'] = 'admin/config/regional/date-time/locale';
}

/**
 * Implement hook_url_outbound_alter().
 *
 * Rewrite outbound URLs with language based prefixes.
 */
function locale_url_outbound_alter(&$path, &$options, $original_path) {
  // Only modify internal URLs.
  if (!$options['external']) {
    static $callbacks;

    if (!isset($callbacks)) {
      $callbacks = array();
      include_once DRUPAL_ROOT . '/includes/language.inc';

      foreach (language_types_configurable() as $type) {
        // Get url rewriter callbacks only from enabled language providers.
        $negotiation = variable_get("language_negotiation_$type", array());

        foreach ($negotiation as $id => $provider) {
          if (isset($provider['file'])) {
            require_once DRUPAL_ROOT . '/' . $provider['file'];
          }

          // Avoid duplicate callback entries.
          if (isset($provider['callbacks']['url_rewrite'])) {
            $callbacks[$provider['callbacks']['url_rewrite']] = NULL;
          }
        }
      }

      $callbacks = array_keys($callbacks);
    }

    foreach ($callbacks as $callback) {
      $callback($path, $options);
    }
  }
}