drupal/core/modules/locale/locale.module

<?php

/**
 * @file
 * 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, and nodes can have languages assigned. The
 * setup of languages and translations is completely web based. Gettext portable
 * object files are supported.
 */

use Drupal\locale\LocaleLookup;
use Drupal\locale\LocaleConfigSubscriber;
use Drupal\locale\SourceString;
use Drupal\locale\StringDatabaseStorage;
use Drupal\locale\TranslationsStream;
use Drupal\Core\Database\Database;

/**
 * Regular expression pattern used to localize JavaScript strings.
 */
const LOCALE_JS_STRING = '(?:(?:\'(?:\\\\\'|[^\'])*\'|"(?:\\\\"|[^"])*")(?:\s*\+\s*)?)+';

/**
 * Regular expression pattern used to match simple JS object literal.
 *
 * This pattern matches a basic JS object, but will fail on an object with
 * nested objects. Used in JS file parsing for string arg processing.
 */
const LOCALE_JS_OBJECT = '\{.*?\}';

/**
 * Regular expression to match an object containing a key 'context'.
 *
 * Pattern to match a JS object containing a 'context key' with a string value,
 * which is captured. Will fail if there are nested objects.
 */
define('LOCALE_JS_OBJECT_CONTEXT', '
  \{              # match object literal start
  .*?             # match anything, non-greedy
  (?:             # match a form of "context"
    \'context\'
    |
    "context"
    |
    context
  )
  \s*:\s*         # match key-value separator ":"
  (' . LOCALE_JS_STRING . ')  # match context string
  .*?             # match anything, non-greedy
  \}              # match end of object literal
');

/**
 * Flag for locally not customized interface translation.
 *
 * Such translations are imported from .po files downloaded from
 * localize.drupal.org for example.
 */
const LOCALE_NOT_CUSTOMIZED = 0;

/**
 * Flag for locally customized interface translation.
 *
 * Such translations are edited from their imported originals on the user
 * interface or are imported as customized.
 */
const LOCALE_CUSTOMIZED = 1;

/**
 * Translation update mode: Use local files only.
 *
 * When checking for available translation updates, only local files will be
 * used. Any remote translation file will be ignored. Also custom modules and
 * themes which have set a "server pattern" to use a remote translation server
 * will be ignored.
 */
const LOCALE_TRANSLATION_USE_SOURCE_LOCAL = 'local';

/**
 * Translation update mode: Use both remote and local files.
 *
 * When checking for available translation updates, both local and remote files
 * will be checked.
 */
const LOCALE_TRANSLATION_USE_SOURCE_REMOTE_AND_LOCAL = 'remote_and_local';

/**
 * Default location of gettext file on the translation server.
 *
 * @see locale_translation_default_translation_server().
 */
const LOCALE_TRANSLATION_DEFAULT_SERVER_PATTERN = 'http://ftp.drupal.org/files/translations/%core/%project/%project-%version.%language.po';

/**
 * The number of seconds that the translations status entry should be considered.
 */
const LOCALE_TRANSLATION_STATUS_TTL = 600;

/**
 * UI option for override of existing translations. Override any translation.
 */
const LOCALE_TRANSLATION_OVERWRITE_ALL = 'all';

/**
 * UI option for override of existing translations. Only override non-customized
 * translations.
 */
const LOCALE_TRANSLATION_OVERWRITE_NON_CUSTOMIZED = 'non_customized';

/**
 * UI option for override of existing translations. Don't override existing
 * translations.
 */
const LOCALE_TRANSLATION_OVERWRITE_NONE = 'none';

/**
 * Translation source is a remote file.
 */
const LOCALE_TRANSLATION_REMOTE = 'remote';

/**
 * Translation source is a local file.
 */
const LOCALE_TRANSLATION_LOCAL = 'local';

/**
 * Translation source is the current translation.
 */
const LOCALE_TRANSLATION_CURRENT = 'current';

/**
 * Translation source is a downloaded file.
 */
const LOCALE_TRANSLATION_DOWNLOADED = 'download';

/**
 * Translation source is an imported file.
 */
const LOCALE_TRANSLATION_IMPORTED = 'import';

/**
 * Implements hook_help().
 */
function locale_help($path, $arg) {
  switch ($path) {
    case 'admin/help#locale':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Locale module allows your Drupal site to be presented in languages other than the default English, and to be multilingual. The Locale module works by maintaining a database of translations, and 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 review by a translator. For more information, see the online handbook entry for <a href="@locale">Locale module</a>.', array('@locale' => 'http://drupal.org/documentation/modules/locale/')) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Translating interface text') . '</dt>';
      $output .= '<dd>' . t('Translations of text in the Drupal interface may be provided by:');
      $output .= '<ul>';
      $output .= '<li>' . t('<a href="@update">Automatic import</a> of translations when you add a language or enable a module or theme. These translations are obtained from the <a href="@url">Drupal translation server</a>. Although Drupal modules and themes may not be fully translated in all languages, new translations become available frequently. Interface translation updates can be downloaded and installed automatically at <a href="@config">regular intervals</a>.', array('@url' => 'http://localize.drupal.org', '@update' => url('admin/reports/translations'), '@config' => url('admin/config/regional/translate/settings'))) . '</li>';
      $output .= '<li>' . t("Translating within your site, using the Locale module's integrated <a href='@translate'>translation interface</a>.", array('@translate' => url('admin/config/regional/translate'))) . '</li>';
      $output .= '<li>' . t("If an existing translations do not meet your needs, the interface translations files in Gettext Portable Object (<em>.po</em>) format may be modified, or new <em>.po</em> files may be created, using a desktop Gettext editor. The Locale module's <a href='@import'>manual 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'))) . '</li>';
      $output .= '</ul></dd>';
      $output .= '</dl>';
      return $output;

    case 'admin/config/regional/language':
      return '<p>' . t('Interface translations are automatically imported when a language is added, or when new modules or themes are enabled. The report, <a href="@update">Available translation updates</a>, shows the status. Interface text can be <a href="@translate">customized</a>.', array('@update' => url('admin/reports/translations'), '@translate' => url('admin/config/regional/translate'))) . '</p>';

    case 'admin/config/regional/translate':
      $output = '<p>' . t('This page allows a translator to search for specific translated and untranslated strings, and is used when creating or editing translations. (Note: Because translation tasks involves 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 in a specific language.', array('@export' => url('admin/config/regional/translate/export'))) . '</p>';
      return $output;

    case 'admin/config/regional/translate/import':
      $output = '<p>' . t('Translation files are automatically downloaded and imported when <a href="@language">languages</a> are added, or when modules or themes are enabled.', array('@language' => url('admin/config/regional/language'))). '</p>';
      $output .= '<p>' . t('For situations where translations need to be manually imported, this page imports the translated strings contained in a Gettext Portable Object (.po) file, which can be downloaded from the <a href="@url">Drupal translation server</a>. Alternatively, a .po file may need to be imported after offline editing in a Gettext translation editor. Importing an individual .po file may be a lengthy process.', array('@url' => 'http://localize.drupal.org')) . '</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>';
  }
}

/**
 * Implements hook_menu().
 */
function locale_menu() {
  // Translation functionality.
  $items['admin/config/regional/translate'] = array(
    'title' => 'User interface translation',
    'description' => 'Translate the built-in user interface.',
    'page callback' => 'locale_translate_page',
    'access arguments' => array('translate interface'),
    'file' => 'locale.pages.inc',
    'weight' => -5,
  );
  $items['admin/config/regional/translate/translate'] = array(
    'title' => 'Translate',
    'weight' => -10,
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $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.bulk.inc',
  );
  $items['admin/config/regional/translate/export'] = array(
    'title' => 'Export',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_translate_export_form'),
    'access arguments' => array('translate interface'),
    'weight' => 30,
    'type' => MENU_LOCAL_TASK,
    'file' => 'locale.bulk.inc',
  );
  $items['admin/config/regional/translate/settings'] = array(
    'title' => 'Settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_translate_settings'),
    'access arguments' => array('translate interface'),
    'weight' => 40,
    'type' => MENU_LOCAL_TASK,
    'file' => 'locale.pages.inc',
  );
  $items['admin/reports/translations'] = array(
    'title' => 'Available translation updates',
    'description' => 'Get a status report about available interface translations for your installed modules and themes.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('locale_translation_status_form'),
    'access arguments' => array('translate interface'),
    'file' => 'locale.pages.inc',
  );
  $items['admin/reports/translations/check'] = array(
    'title' => 'Manual translation update check',
    'page callback' => 'locale_translation_manual_status',
    'access arguments' => array('translate interface'),
    'type' => MENU_CALLBACK,
    'file' => 'locale.pages.inc',
  );

  return $items;
}

/**
 * Implements hook_permission().
 */
function locale_permission() {
  return array(
    'translate interface' => array(
      'title' => t('Translate interface texts'),
      'restrict access' => TRUE,
    ),
  );
}

/**
 * Implements hook_theme().
 */
function locale_theme() {
  return array(
    'locale_translate_edit_form_strings' => array(
      'render element' => 'form',
      'file' => 'locale.pages.inc',
    ),
  );
}

/**
 * Implements hook_stream_wrappers().
 */
function locale_stream_wrappers() {
  $wrappers = array(
    'translations' => array(
      'name' => t('Translation files'),
      'class' => 'Drupal\locale\TranslationsStream',
      'description' => t('Translation files'),
      'type' => STREAM_WRAPPERS_LOCAL_HIDDEN,
    ),
  );
  return $wrappers;
}

/**
 * Implements hook_language_insert().
 */
function locale_language_insert($language) {
  // @todo move these two cache clears out. See http://drupal.org/node/1293252
  // Changing the language settings impacts the interface.
  cache('page')->deleteAll();
  // Force JavaScript translation file re-creation for the new language.
  _locale_invalidate_js($language->langcode);
}

/**
 * Implements hook_language_update().
 */
function locale_language_update($language) {
  // @todo move these two cache clears out. See http://drupal.org/node/1293252
  // Changing the language settings impacts the interface.
  cache('page')->deleteAll();
  // Force JavaScript translation file re-creation for the modified language.
  _locale_invalidate_js($language->langcode);
}

/**
 * Implements hook_language_delete().
 */
function locale_language_delete($language) {
  // Remove translations.
  locale_storage()->deleteTranslations(array('language' => $language->langcode));

  // Remove interface translation files.
  module_load_include('inc', 'locale', 'locale.bulk');
  locale_translate_delete_translation_files(array(), array($language->langcode));

  // Changing the language settings impacts the interface:
  _locale_invalidate_js($language->langcode);
  cache('page')->deleteAll();

  // Clear locale translation caches.
  locale_translation_status_delete_languages(array($language->langcode));
  cache()->delete('locale:' . $language->langcode);
}

/**
 * Returns list of translatable languages.
 *
 * @return array
 *   Array of installed languages keyed by language name. English is omitted
 *   unless it is marked as translatable.
 */
function locale_translatable_language_list() {
  $languages = language_list();
  if (!locale_translate_english()) {
    unset($languages['en']);
  }
  return $languages;
}

/**
 * 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 $langcode
 *   Language code to use for the lookup.
 */
function locale($string = NULL, $context = NULL, $langcode = NULL) {
  $language_interface = language(LANGUAGE_TYPE_INTERFACE);

  // Use the advanced drupal_static() pattern, since this is called very often.
  static $drupal_static_fast;
  if (!isset($drupal_static_fast)) {
    $drupal_static_fast['locale'] = &drupal_static(__FUNCTION__, array('cache' => array(), 'exists' => NULL));
  }
  $locale_t = &$drupal_static_fast['locale']['cache'];
  $locale_exists = &$drupal_static_fast['locale']['exists'];

  // Check whether Locale module is actually installed and operational.
  // The mere existence of locale() does not imply that Locale module is
  // actually enabled and its database tables are installed. Since PHP code
  // cannot be unloaded, this is typically the case in the environment that
  // is executing a test.
  if (!isset($locale_exists)) {
    $locale_exists = function_exists('module_exists') && module_exists('locale');
  }
  if (!$locale_exists) {
    return $string;
  }

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

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

  // Strings are cached by langcode, context and roles, using instances of the
  // LocaleLookup class to handle string lookup and caching.
  if (!isset($locale_t[$langcode][$context]) && isset($language_interface)) {
    $locale_t[$langcode][$context] = new LocaleLookup($langcode, $context, locale_storage());
  }
  return ($locale_t[$langcode][$context][$string] === TRUE ? $string : $locale_t[$langcode][$context][$string]);
}

/**
 * Reset static variables used by locale().
 */
function locale_reset() {
  drupal_static_reset('locale');
}

/**
 * Gets the locale storage controller class .
 *
 * @return Drupal\locale\StringStorageInterface
 */
function locale_storage() {
  $storage = &drupal_static(__FUNCTION__);
  if (!isset($storage)) {
    $options = array('target' => 'default');
    $storage = new StringDatabaseStorage(Database::getConnection($options['target']), $options);
  }
  return $storage;
}

/**
 * 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.
 * @return
 *   The numeric index of the plural variant to use for this $langcode and
 *   $count combination or -1 if the language was not found or does not have a
 *   plural formula.
 */
function locale_get_plural($count, $langcode = NULL) {
  $language_interface = language(LANGUAGE_TYPE_INTERFACE);

  // Used to locally cache the plural formulas for all languages.
  $plural_formulas = &drupal_static(__FUNCTION__, array());
  // Used to store precomputed plural indexes corresponding to numbers
  // individually for each language.
  $plural_indexes = &drupal_static(__FUNCTION__ . ':plurals', array());

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

  if (!isset($plural_indexes[$langcode][$count])) {
    // Retrieve and statically cache the plural formulas for all languages.
    if (empty($plural_formulas)) {
      $plural_formulas = variable_get('locale_translation_plurals', array());
    }
    // If there is a plural formula for the language, evaluate it for the given
    // $count and statically cache the result for the combination of language
    // and count, since the result will always be identical.
    if (!empty($plural_formulas[$langcode])) {
      // $n is used inside the expression in the eval().
      $n = $count;
      $plural_indexes[$langcode][$count] = @eval('return intval(' . $plural_formulas[$langcode]['formula'] . ');');
    }
    // In case there is no plural formula for English (no imported translation
    // for English), use a default formula.
    elseif ($langcode == 'en') {
      $plural_indexes[$langcode][$count] = (int) ($count != 1);
    }
    // Otherwise, return -1 (unknown).
    else {
      $plural_indexes[$langcode][$count] = -1;
    }
  }
  return $plural_indexes[$langcode][$count];
}


/**
 * Implements hook_modules_installed().
 */
function locale_modules_installed($modules) {
  locale_system_update($modules);
}

/**
 * Implements hook_modules_uninstalled().
 */
function locale_modules_uninstalled($modules) {
  locale_system_remove($modules);
}

/**
 * Implements hook_themes_enabled().
 *
 * @todo This is technically wrong. We must not import upon enabling, but upon
 *   initial installation. The theme system is missing an installation hook.
 */
function locale_themes_enabled($themes) {
  locale_system_update($themes);
}

/**
 * Implements hook_themes_disabled().
 */
function locale_themes_disabled($themes) {
  locale_system_remove($themes);
}

/**
 * Imports translations when new modules or themes are installed.
 *
 * This function will start a batch to import translations for the added
 * components.
 *
 * @param array $components
 *   An array of component (theme and/or module) names to import
 *   translations for.
 */
function locale_system_update($components) {
  // Skip running the translation imports if in the installer,
  // because it would break out of the installer flow. We have
  // built-in support for translation imports in the installer.
  if (!drupal_installation_attempted() && locale_translatable_language_list()) {
    module_load_include('compare.inc', 'locale');

    // Update the list of translatable projects and start the import batch.
    // Only when new projects are added the update batch will be triggered. Not
    // each enabled module will introduce a new project. E.g. sub modules.
    $projects = array_keys(locale_translation_build_projects());
    if ($components = array_intersect($components, $projects)) {
      module_load_include('fetch.inc', 'locale');
      // Get translation status of the projects, download and update translations.
      $options = _locale_translation_default_update_options();
      $batch = locale_translation_batch_update_build($components, array(), $options);
      batch_set($batch);
    }
  }
}

/**
 * Delete translation history of modules and themes.
 *
 * Only the translation history is removed, not the source strings or
 * translations. This is not possible because strings are shared between
 * modules and we have no record of which string is used by which module.
 *
 * @param array $components
 *   An array of component (theme and/or module) names to remove
 *   translation history.
 */
function locale_system_remove($components) {
  if (locale_translatable_language_list()) {
    module_load_include('compare.inc', 'locale');

    // Only when projects are removed, the translation files and records will be
    // deleted. Not each disabled module will remove a project. E.g. sub modules.
    $projects = array_keys(locale_translation_get_projects());
    if ($components = array_intersect($components, $projects)) {
      locale_translation_file_history_delete($components);

      // Remove translation files.
      module_load_include('inc', 'locale', 'locale.bulk');
      locale_translate_delete_translation_files($components, array());

      // Remove translatable projects.
      // Followup issue http://drupal.org/node/1842362 to replace the
      // {locale_project} table. Then change this to a function call.
      db_delete('locale_project')
        ->condition('name', $components)
        ->execute();

      // Clear the translation status.
      locale_translation_status_delete_projects($components);
    }
  }
}


/**
 * Implements 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) {
  $language_interface = language(LANGUAGE_TYPE_INTERFACE);

  $dir = 'public://' . variable_get('locale_js_directory', 'languages');
  $parsed = state()->get('system.javascript_parsed') ?: array();
  $files = $new_files = FALSE;

  foreach ($javascript as $item) {
    if (isset($item['type']) && $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)) != $dir) {
          _locale_parse_js_file($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_invalidate_js();
  }

  // If necessary, rebuild the translation file for the current language.
  if (!empty($parsed['refresh:' . $language_interface->langcode])) {
    // Don't clear the refresh flag on failure, so that another try will
    // be performed later.
    if (_locale_rebuild_js()) {
      unset($parsed['refresh:' . $language_interface->langcode]);
    }
    // Store any changes after refresh was attempted.
    state()->set('system.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) {
    state()->set('system.javascript_parsed', $parsed);
  }

  // Add the translation JavaScript file to the page.
  $locale_javascripts = variable_get('locale_translation_javascript', array());
  if ($files && !empty($locale_javascripts[$language_interface->langcode])) {
    // Add the translation JavaScript file to the page.
    $file = $dir . '/' . $language_interface->langcode . '_' . $locale_javascripts[$language_interface->langcode] . '.js';
    $javascript[$file] = drupal_js_defaults($file);
  }
}

/**
 * Implements hook_library_info().
 */
function locale_library_info() {
  $libraries['drupal.locale.admin'] = array(
    'title' => 'Locale',
    'version' => VERSION,
    'js' => array(
      drupal_get_path('module', 'locale') . '/locale.admin.js' => array(),
    ),
    'dependencies' => array(
      array('system', 'jquery'),
      array('system', 'drupal'),
      array('system', 'jquery.once'),
    ),
  );
  $libraries['drupal.locale.datepicker'] = array(
    'title' => 'Locale Datepicker UI',
    'version' => VERSION,
    'js' => array(
      drupal_get_path('module', 'locale') . '/locale.datepicker.js' => array(),
    ),
    'dependencies' => array(
      array('system', 'jquery'),
      array('system', 'drupal'),
      array('system', 'drupalSettings'),
    ),
  );

  return $libraries;
}

/**
 * Implement hook_library_info_alter().
 *
 * Provides the language support for the jQuery UI Date Picker.
 */
function locale_library_info_alter(&$libraries, $module) {
  if ($module == 'system' && isset($libraries['jquery.ui.datepicker'])) {
    $language_interface = language(LANGUAGE_TYPE_INTERFACE);
    // locale.datepicker.js should be added in the JS_LIBRARY group, so that
    // this attach behavior will execute early. JS_LIBRARY is the default for
    // hook_library_info_alter(), thus does not have to be specified explicitly.
    $libraries['jquery.ui.datepicker']['dependencies'][] = array('locale', 'drupal.locale.datepicker');
    $libraries['jquery.ui.datepicker']['js'][] = array(
      'data' => array(
        'jquery' => array(
          'ui' => array(
            'datepicker' => array(
              'isRTL' => $language_interface->direction == LANGUAGE_RTL,
              'firstDay' => config('system.date')->get('first_day'),
            ),
          ),
        ),
      ),
      'type' => 'setting',
    );
  }
}

/**
 * Implements hook_form_FORM_ID_alter() for language_admin_overview_form().
 */
function locale_form_language_admin_overview_form_alter(&$form, &$form_state) {
  $languages = $form['languages']['#languages'];

  $total_strings = locale_storage()->countStrings();
  $stats = array_fill_keys(array_keys($languages), array());

  // If we have source strings, count translations and calculate progress.
  if (!empty($total_strings)) {
    $translations = locale_storage()->countTranslations();
    foreach ($translations as $langcode => $translated) {
      $stats[$langcode]['translated'] = $translated;
      if ($translated > 0) {
        $stats[$langcode]['ratio'] = round($translated / $total_strings * 100, 2);
      }
    }
  }

  array_splice($form['languages']['#header'], -1, 0, t('Interface translation'));

  foreach ($languages as $langcode => $language) {
    $stats[$langcode] += array(
      'translated' => 0,
      'ratio' => 0,
    );
    if (!$language->locked && ($langcode != 'en' || locale_translate_english())) {
      $form['languages'][$langcode]['locale_statistics'] = array(
        '#markup' => l(
          t('@translated/@total (@ratio%)', array(
            '@translated' => $stats[$langcode]['translated'],
            '@total' => $total_strings,
            '@ratio' => $stats[$langcode]['ratio'],
          )),
          'admin/config/regional/translate/translate',
          array('query' => array('langcode' => $langcode))
        ),
      );
    }
    else {
      $form['languages'][$langcode]['locale_statistics'] = array(
        '#markup' => t('not applicable'),
      );
    }
  }
}

/**
 * Implements hook_form_FORM_ID_alter() for language_admin_add_form(().
 */
function locale_form_language_admin_add_form_alter(&$form, &$form_state) {
  $form['predefined_submit']['#submit'][] = 'locale_form_language_admin_add_form_alter_submit';
  $form['custom_language']['submit']['#submit'][] = 'locale_form_language_admin_add_form_alter_submit';
}

/**
 * Form submission handler for language_admin_add_form().
 *
 * Set a batch for a newly-added language.
 */
function locale_form_language_admin_add_form_alter_submit($form, $form_state) {
  if (empty($form_state['values']['predefined_langcode']) || $form_state['values']['predefined_langcode'] == 'custom') {
    $langcode = $form_state['values']['langcode'];
  }
  else {
    $langcode = $form_state['values']['predefined_langcode'];
  }

  // Download and import translations for the newly added language.
  module_load_include('fetch.inc', 'locale');
  $options = _locale_translation_default_update_options();
  $batch = locale_translation_batch_update_build(array(), array($langcode), $options);
  batch_set($batch);
}

/**
 * Implements hook_form_FORM_ID_alter() for language_admin_edit_form().
 */
function locale_form_language_admin_edit_form_alter(&$form, &$form_state) {
  if ($form['langcode']['#type'] == 'value' && $form['langcode']['#value'] == 'en') {
    $form['locale_translate_english'] = array(
      '#title' => t('Enable interface translation to English'),
      '#type' => 'checkbox',
      '#default_value' => locale_translate_english(),
    );
    $form['#submit'][] = 'locale_form_language_admin_edit_form_alter_submit';
  }
}

/**
 * Form submission handler for language_admin_edit_form().
 */
function locale_form_language_admin_edit_form_alter_submit($form, $form_state) {
  variable_set('locale_translate_english', $form_state['values']['locale_translate_english']);
}

/**
 * Checks whether locale translates to English.
 *
 * @return bool
 *   Returns TRUE if content should be translated to English, FALSE otherwise.
 */
function locale_translate_english() {
  return variable_get('locale_translate_english', FALSE);
}

/**
 * Implements hook_form_FORM_ID_alter() for system_file_system_settings().
 *
 * Add interface translation directory setting to directories configuration.
 */
function locale_form_system_file_system_settings_alter(&$form, $form_state) {
  $form['locale_translate_file_directory'] = array(
    '#type' => 'textfield',
    '#title' => t('Interface translations directory'),
    '#default_value' => variable_get('locale_translate_file_directory', conf_path() . '/files/translations'),
    '#maxlength' => 255,
    '#description' => t('A local file system path where interface translation files will be stored.'),
    '#after_build' => array('system_check_directory'),
    '#weight' => 10,
  );
  if ($form['file_default_scheme']) {
    $form['file_default_scheme']['#weight'] = 20;
  }
  $form['#submit'][] = 'locale_system_file_system_settings_submit';
}

/**
 * Submit handler for the file system settings form.
 *
 * Clears the translation status when the Interface translations directory
 * changes. Without a translations directory local po files in the directory
 * should be ignored. The old translation status is no longer valid.
 */
function locale_system_file_system_settings_submit(&$form, $form_state) {
  if ($form['locale_translate_file_directory']['#default_value'] != $form_state['values']['locale_translate_file_directory']) {
    locale_translation_clear_status();
  }
}

/**
 * Implements hook_preprocess_HOOK() for node.tpl.php.
 */
function locale_preprocess_node(&$variables) {
  if ($variables['node']->langcode != LANGUAGE_NOT_SPECIFIED) {
    $language_interface = language(LANGUAGE_TYPE_INTERFACE);

    $node_language = language_load($variables['node']->langcode);
    if ($node_language->langcode != $language_interface->langcode) {
      // If the node language was different from the page language, we should
      // add markup to identify the language. Otherwise the page language is
      // inherited.
      $variables['attributes']['lang'] = $variables['node']->langcode;
      if ($node_language->direction != $language_interface->direction) {
        // If text direction is different form the page's text direction, add
        // direction information as well.
        $dir = array('ltr', 'rtl');
        $variables['attributes']['dir'] = $dir[$node_language->direction];
      }
    }
  }
}

/**
 * Gets current translation status from the {locale_file} table.
 *
 * @return array
 *   Array of translation file objects.
 */
function locale_translation_get_file_history() {
  $history = &drupal_static(__FUNCTION__, array());

  if (empty($history)) {
    // Get file history from the database.
    $result = db_query('SELECT project, langcode, filename, version, uri, timestamp, last_checked FROM {locale_file}');
    foreach ($result as $file) {
      $file->type = LOCALE_TRANSLATION_CURRENT;
      $history[$file->project][$file->langcode] = $file;
    }
  }
  return $history;
}

/**
 * Updates the {locale_file} table.
 *
 * @param object $file
 *   Object representing the file just imported.
 *
 * @return integer
 *   FALSE on failure. Otherwise SAVED_NEW or SAVED_UPDATED.
 *
 * @see drupal_write_record()
 */
function locale_translation_update_file_history($file) {
  // Update or write new record.
  if (db_query("SELECT project FROM {locale_file} WHERE project = :project AND langcode = :langcode", array(':project' => $file->project, ':langcode' => $file->langcode))->fetchField()) {
    $update = array('project', 'langcode');
  }
  else {
    $update = array();
  }
  return drupal_write_record('locale_file', $file, $update);
}

/**
 * Deletes the history of downloaded translations.
 *
 * @param array $projects
 *   Project name(s) to be deleted from the file history. If both project(s) and
 *   language code(s) are specified the conditions will be ANDed.
 * @param array $langcode
 *   Language code(s) to be deleted from the file history.
 */
function locale_translation_file_history_delete($projects = array(), $langcodes = array()) {
  $query = db_delete('locale_file');
  if (!empty($projects)) {
    $query->condition('project', $projects);
  }
  if (!empty($langcodes)) {
    $query->condition('langcode', $langcodes);
  }
  $query->execute();
}

/**
 * Saves the status of translation sources in static cache.
 *
 * @param array $data
 *   Array of translation source data, structured by project name and langcode.
 */
function locale_translation_status_save($data) {
  // Followup issue: http://drupal.org/node/1842362
  // Split status storage per module/language and expire individually. This will
  // improve performance for large sites.
  $status = state()->get('locale.translation_status');
  $status = empty($status) ? array() : $status;

  // Merge the new data into the existing structured status array.
  foreach ($data as $project => $languages) {
    foreach ($languages as $langcode => $source) {
      $status[$project][$langcode] = $source;
    }
  }

  state()->set('locale.translation_status', $status);
  state()->set('locale.translation_last_checked', REQUEST_TIME);
}

/**
 * Delete language entries from the status cache.
 *
 * @param array $langcodes
 *   Language code(s) to be deleted from the cache.
 */
function locale_translation_status_delete_languages($langcodes) {
  if ($status = state()->get('locale.translation_status')) {
    foreach ($status as $project => $languages) {
      foreach ($languages as $langcode => $source) {
        if (in_array($langcode, $langcodes)) {
          unset($status[$project][$langcode]);
        }
      }
    }
    state()->set('locale.translation_status', $status);
  }
}

/**
 * Delete project entries from the status cache.
 *
 * @param array $projects
 *   Project name(s) to be deleted from the cache.
 */
function locale_translation_status_delete_projects($projects) {
  $status = state()->get('locale.translation_status');

  foreach ($status as $project => $languages) {
    if (in_array($project, $projects)) {
      unset($status[$project]);
    }
  }
  state()->set('locale.translation_status', $status);
}

/**
 * Clear the translation status cache.
 */
function locale_translation_clear_status() {
  state()->delete('locale.translation_status');
  state()->delete('locale.translation_last_checked');
}

/**
 * Checks whether remote translation sources are used.
 *
 * @return bool
 *   Returns TRUE if remote translations sources should be taken into account
 *   when checking or importing translation files, FALSE otherwise.
 */
function locale_translation_use_remote_source() {
  return config('locale.settings')->get('translation.use_source') == LOCALE_TRANSLATION_USE_SOURCE_REMOTE_AND_LOCAL;
}

/**
 * Check that a string is safe to be added or imported as a translation.
 *
 * This test can be used to detect possibly bad translation strings. It should
 * not have any false positives. But it is only a test, not a transformation,
 * as it destroys valid HTML. We cannot reliably filter translation strings
 * on import because some strings are irreversibly corrupted. For example,
 * a &amp; in the translation would get encoded to &amp;amp; by filter_xss()
 * before being put in the database, and thus would be displayed incorrectly.
 *
 * The allowed tag list is like filter_xss_admin(), but omitting div and img as
 * not needed for translation and likely to cause layout issues (div) or a
 * possible attack vector (img).
 */
function locale_string_is_safe($string) {
  return decode_entities($string) == decode_entities(filter_xss($string, array('a', 'abbr', 'acronym', 'address', 'b', 'bdo', 'big', 'blockquote', 'br', 'caption', 'cite', 'code', 'col', 'colgroup', 'dd', 'del', 'dfn', 'dl', 'dt', 'em', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'i', 'ins', 'kbd', 'li', 'ol', 'p', 'pre', 'q', 'samp', 'small', 'span', 'strong', 'sub', 'sup', 'table', 'tbody', 'td', 'tfoot', 'th', 'thead', 'tr', 'tt', 'ul', 'var')));
}

/**
 * Refresh related information after string translations have been updated.
 *
 * The information that will be refreshed includes:
 * - JavaScript translations.
 * - Locale cache.
 *
 * @param array $langcodes
 *   Language codes for updated translations.
 * @param array $lids
 *   List of string identifiers that have been updated / created.
 */
function _locale_refresh_translations($langcodes, $lids) {
  if ($lids && $langcodes) {
    // Update javascript translations if any of the strings has a javascript location.
    if ($strings = locale_storage()->getStrings(array('lid' => $lids, 'type' => 'javascript'))) {
      array_map('_locale_invalidate_js', $langcodes);
    }
  }
  // Clear locale cache.
  cache()->deleteTags(array('locale' => TRUE));
}

/**
 * Parses a JavaScript file, extracts strings wrapped in Drupal.t() and
 * Drupal.formatPlural() and inserts them into the database.
 *
 * @param string $filepath
 *   File name to parse.
 *
 * @return array
 *   Array of string objects to update indexed by context and source.
 */
function _locale_parse_js_file($filepath) {
  // The file path might contain a query string, so make sure we only use the
  // actual file.
  $parsed_url = drupal_parse_url($filepath);
  $filepath = $parsed_url['path'];
  // Load the JavaScript file.
  $file = file_get_contents($filepath);

  // Match all calls to Drupal.t() in an array.
  // Note: \s also matches newlines with the 's' modifier.
  preg_match_all('~
    [^\w]Drupal\s*\.\s*t\s*                       # match "Drupal.t" with whitespace
    \(\s*                                         # match "(" argument list start
    (' . LOCALE_JS_STRING . ')\s*                 # capture string argument
    (?:,\s*' . LOCALE_JS_OBJECT . '\s*            # optionally capture str args
      (?:,\s*' . LOCALE_JS_OBJECT_CONTEXT . '\s*) # optionally capture context
    ?)?                                           # close optional args
    [,\)]                                         # match ")" or "," to finish
    ~sx', $file, $t_matches);

  // Match all Drupal.formatPlural() calls in another array.
  preg_match_all('~
    [^\w]Drupal\s*\.\s*formatPlural\s*  # match "Drupal.formatPlural" with whitespace
    \(                                  # match "(" argument list start
    \s*.+?\s*,\s*                       # match count argument
    (' . LOCALE_JS_STRING . ')\s*,\s*   # match singular string argument
    (                             # capture plural string argument
      (?:                         # non-capturing group to repeat string pieces
        (?:
          \'                      # match start of single-quoted string
          (?:\\\\\'|[^\'])*       # match any character except unescaped single-quote
          @count                  # match "@count"
          (?:\\\\\'|[^\'])*       # match any character except unescaped single-quote
          \'                      # match end of single-quoted string
          |
          "                       # match start of double-quoted string
          (?:\\\\"|[^"])*         # match any character except unescaped double-quote
          @count                  # match "@count"
          (?:\\\\"|[^"])*         # match any character except unescaped double-quote
          "                       # match end of double-quoted string
        )
        (?:\s*\+\s*)?             # match "+" with possible whitespace, for str concat
      )+                          # match multiple because we supports concatenating strs
    )\s*                          # end capturing of plural string argument
    (?:,\s*' . LOCALE_JS_OBJECT . '\s*          # optionally capture string args
      (?:,\s*' . LOCALE_JS_OBJECT_CONTEXT . '\s*)?  # optionally capture context
    )?
    [,\)]
    ~sx', $file, $plural_matches);

  $matches = array();

  // Add strings from Drupal.t().
  foreach ($t_matches[1] as $key => $string) {
    $matches[] = array(
      'string'  => $string,
      'context' => $t_matches[2][$key],
    );
  }

  // Add string from Drupal.formatPlural().
  foreach ($plural_matches[1] as $key => $string) {
    $matches[] = array(
      'string'  => $string,
      'context' => $plural_matches[3][$key],
    );

    // If there is also a plural version of this string, add it to the strings array.
    if (isset($plural_matches[2][$key])) {
      $matches[] = array(
        'string'  => $plural_matches[2][$key],
        'context' => $plural_matches[3][$key],
      );
    }
  }

  // Loop through all matches and process them.
  foreach ($matches as $key => $match) {

    // Remove the quotes and string concatenations from the string and context.
    $string =  implode('', preg_split('~(?<!\\\\)[\'"]\s*\+\s*[\'"]~s', substr($match['string'], 1, -1)));
    $context = implode('', preg_split('~(?<!\\\\)[\'"]\s*\+\s*[\'"]~s', substr($match['context'], 1, -1)));

    $source = locale_storage()->findString(array('source' => $string, 'context' => $context));

    if (!$source) {
      // We don't have the source string yet, thus we insert it into the database.
      $source = locale_storage()->createString(array(
        'source'    => $string,
        'context'   => $context,
      ));
    }
    // Besides adding the location this will tag it for current version.
    $source->addLocation('javascript', $filepath);
    $source->save();
  }
}

/**
 * Force the JavaScript translation file(s) to be refreshed.
 *
 * This function sets a refresh flag for a specified language, or all
 * languages except English, if none specified. JavaScript translation
 * files are rebuilt (with locale_update_js_files()) the next time a
 * request is served in that language.
 *
 * @param $langcode
 *   The language code for which the file needs to be refreshed.
 *
 * @return
 *   New content of the 'system.javascript_parsed' variable.
 */
function _locale_invalidate_js($langcode = NULL) {
  $parsed = state()->get('system.javascript_parsed') ?: array();

  if (empty($langcode)) {
    // Invalidate all languages.
    $languages = locale_translatable_language_list();
    foreach ($languages as $lcode => $data) {
      $parsed['refresh:' . $lcode] = 'waiting';
    }
  }
  else {
    // Invalidate single language.
    $parsed['refresh:' . $langcode] = 'waiting';
  }

  state()->set('system.javascript_parsed', $parsed);
  return $parsed;
}

/**
 * (Re-)Creates the JavaScript translation file for a language.
 *
 * @param $langcode
 *   The language, the translation file should be (re)created for.
 */
function _locale_rebuild_js($langcode = NULL) {
  if (!isset($langcode)) {
    $language = language(LANGUAGE_TYPE_INTERFACE);
  }
  else {
    // Get information about the locale.
    $languages = language_list();
    $language = $languages[$langcode];
  }

  // Construct the array for JavaScript translations.
  // Only add strings with a translation to the translations array.
  $conditions = array(
    'type' => 'javascript',
    'language' =>  $language->langcode,
    'translated' => TRUE,
  );
  $translations = array();
  foreach (locale_storage()->getTranslations($conditions) as $data) {
    $translations[$data->context][$data->source] = $data->translation;
  }

  // Construct the JavaScript file, if there are translations.
  $data_hash = NULL;
  $data = $status = '';
  if (!empty($translations)) {

    $data = "Drupal.locale = { ";

    $locale_plurals = variable_get('locale_translation_plurals', array());
    if (!empty($locale_plurals[$language->langcode])) {
      $data .= "'pluralFormula': function (\$n) { return Number({$locale_plurals[$language->langcode]['formula']}); }, ";
    }

    $data .= "'strings': " . drupal_json_encode($translations) . " };";
    $data_hash = drupal_hash_base64($data);
  }

  // Construct the filepath where JS translation files are stored.
  // There is (on purpose) no front end to edit that variable.
  $dir = 'public://' . variable_get('locale_js_directory', 'languages');

  // Delete old file, if we have no translations anymore, or a different file to be saved.
  $locale_javascripts = variable_get('locale_translation_javascript', array());
  $changed_hash = !isset($locale_javascripts[$language->langcode]) || ($locale_javascripts[$language->langcode] != $data_hash);
  if (!empty($locale_javascripts[$language->langcode]) && (!$data || $changed_hash)) {
    file_unmanaged_delete($dir . '/' . $language->langcode . '_' . $locale_javascripts[$language->langcode] . '.js');
    $locale_javascripts[$language->langcode] = '';
    $status = 'deleted';
  }

  // Only create a new file if the content has changed or the original file got
  // lost.
  $dest = $dir . '/' . $language->langcode . '_' . $data_hash . '.js';
  if ($data && ($changed_hash || !file_exists($dest))) {
    // Ensure that the directory exists and is writable, if possible.
    file_prepare_directory($dir, FILE_CREATE_DIRECTORY);

    // Save the file.
    if (file_unmanaged_save_data($data, $dest)) {
      $locale_javascripts[$language->langcode] = $data_hash;
      // If we deleted a previous version of the file and we replace it with a
      // new one we have an update.
      if ($status == 'deleted') {
        $status = 'updated';
      }
      // If the file did not exist previously and the data has changed we have
      // a fresh creation.
      elseif ($changed_hash) {
        $status = 'created';
      }
      // If the data hash is unchanged the translation was lost and has to be
      // rebuilt.
      else {
        $status = 'rebuilt';
      }
    }
    else {
      $locale_javascripts[$language->langcode] = '';
      $status = 'error';
    }
  }

  // Save the new JavaScript hash (or an empty value if the file just got
  // deleted). Act only if some operation was executed that changed the hash
  // code.
  if ($status && $changed_hash) {
    variable_set('locale_translation_javascript', $locale_javascripts);
  }

  // Log the operation and return success flag.
  switch ($status) {
    case 'updated':
      watchdog('locale', 'Updated JavaScript translation file for the language %language.', array('%language' => $language->name));
      return TRUE;
    case 'rebuilt':
      watchdog('locale', 'JavaScript translation file %file.js was lost.', array('%file' => $locale_javascripts[$language->langcode]), WATCHDOG_WARNING);
      // Proceed to the 'created' case as the JavaScript translation file has
      // been created again.
    case 'created':
      watchdog('locale', 'Created JavaScript translation file for the language %language.', array('%language' => $language->name));
      return TRUE;
    case 'deleted':
      watchdog('locale', 'Removed JavaScript translation file for the language %language because no translations currently exist for that language.', array('%language' => $language->name));
      return TRUE;
    case 'error':
      watchdog('locale', 'An error occurred during creation of the JavaScript translation file for the language %language.', array('%language' => $language->name), WATCHDOG_ERROR);
      return FALSE;
    default:
      // No operation needed.
      return TRUE;
  }
}

/**
 * Implements hook_language_init().
 */
function locale_language_init() {
  // Add locale helper to configuration subscribers.
  drupal_container()->get('dispatcher')->addSubscriber(new LocaleConfigSubscriber());
}