locale.inc

<?php

/**
 * @file
 * Administration functions for locale.module.
 */

/**
 * 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 interface language.
 */
define('LOCALE_LANGUAGE_NEGOTIATION_INTERFACE', 'locale-interface');

/**
 * If no URL language is available language is determined using an already
 * detected one.
 */
define('LOCALE_LANGUAGE_NEGOTIATION_URL_FALLBACK', 'locale-url-fallback');

/**
 * 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');

/**
 * Regular expression pattern used to localize JavaScript strings.
 */
define('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.
 */
define('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
');

/**
 * Translation import mode overwriting all existing translations
 * if new translated version available.
 */
define('LOCALE_IMPORT_OVERWRITE', 0);

/**
 * Translation import mode keeping existing translations and only
 * inserting new strings.
 */
define('LOCALE_IMPORT_KEEP', 1);

/**
 * URL language negotiation: use the path prefix as URL language
 * indicator.
 */
define('LOCALE_LANGUAGE_NEGOTIATION_URL_PREFIX', 0);

/**
 * URL language negotiation: use the domain as URL language
 * indicator.
 */
define('LOCALE_LANGUAGE_NEGOTIATION_URL_DOMAIN', 1);

/**
 * @defgroup locale-languages-negotiation Language negotiation options
 * @{
 * Functions for language negotiation.
 *
 * There are functions that provide the ability to identify the
 * language. This behavior can be controlled by various options.
 */

/**
 * Identifies the language from the current interface language.
 *
 * @return
 *   The current interface language code.
 */
function locale_language_from_interface() {
  global $language;
  return isset($language->language) ? $language->language : FALSE;
}

/**
 * Identify language from the Accept-language HTTP header we got.
 *
 * We perform browser accept-language parsing only if page cache is disabled,
 * otherwise we would cache a user-specific preference.
 *
 * @param $languages
 *   An array of language objects for enabled languages ordered by weight.
 *
 * @return
 *   A valid language code on success, FALSE otherwise.
 */
function locale_language_from_browser($languages) {
  if (empty($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
    return FALSE;
  }

  // The Accept-Language header contains information about the language
  // preferences configured in the user's browser / operating system.
  // RFC 2616 (section 14.4) defines the Accept-Language header as follows:
  //   Accept-Language = "Accept-Language" ":"
  //                  1#( language-range [ ";" "q" "=" qvalue ] )
  //   language-range  = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" )
  // Samples: "hu, en-us;q=0.66, en;q=0.33", "hu,en-us;q=0.5"
  $browser_langcodes = array();
  if (preg_match_all('@([a-zA-Z-]+|\*)(?:;q=([0-9.]+))?(?:$|\s*,\s*)@', trim($_SERVER['HTTP_ACCEPT_LANGUAGE']), $matches, PREG_SET_ORDER)) {
    foreach ($matches as $match) {
      // We can safely use strtolower() here, tags are ASCII.
      // RFC2616 mandates that the decimal part is no more than three digits,
      // so we multiply the qvalue by 1000 to avoid floating point comparisons.
      $langcode = strtolower($match[1]);
      $qvalue = isset($match[2]) ? (float) $match[2] : 1;
      $browser_langcodes[$langcode] = (int) ($qvalue * 1000);
    }
  }

  // We should take pristine values from the HTTP headers, but Internet Explorer
  // from version 7 sends only specific language tags (eg. fr-CA) without the
  // corresponding generic tag (fr) unless explicitly configured. In that case,
  // we assume that the lowest value of the specific tags is the value of the
  // generic language to be as close to the HTTP 1.1 spec as possible.
  // See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4 and
  // http://blogs.msdn.com/b/ie/archive/2006/10/17/accept-language-header-for-internet-explorer-7.aspx
  asort($browser_langcodes);
  foreach ($browser_langcodes as $langcode => $qvalue) {
    $generic_tag = strtok($langcode, '-');
    if (!isset($browser_langcodes[$generic_tag])) {
      $browser_langcodes[$generic_tag] = $qvalue;
    }
  }

  // Find the enabled language with the greatest qvalue, following the rules
  // of RFC 2616 (section 14.4). If several languages have the same qvalue,
  // prefer the one with the greatest weight.
  $best_match_langcode = FALSE;
  $max_qvalue = 0;
  foreach ($languages as $langcode => $language) {
    // Language tags are case insensitive (RFC2616, sec 3.10).
    $langcode = strtolower($langcode);

    // If nothing matches below, the default qvalue is the one of the wildcard
    // language, if set, or is 0 (which will never match).
    $qvalue = isset($browser_langcodes['*']) ? $browser_langcodes['*'] : 0;

    // Find the longest possible prefix of the browser-supplied language
    // ('the language-range') that matches this site language ('the language tag').
    $prefix = $langcode;
    do {
      if (isset($browser_langcodes[$prefix])) {
        $qvalue = $browser_langcodes[$prefix];
        break;
      }
    }
    while ($prefix = substr($prefix, 0, strrpos($prefix, '-')));

    // Find the best match.
    if ($qvalue > $max_qvalue) {
      $best_match_langcode = $language->language;
      $max_qvalue = $qvalue;
    }
  }

  return $best_match_langcode;
}

/**
 * Identify language from the user preferences.
 *
 * @param $languages
 *   An array of valid language objects.
 *
 * @return
 *   A valid language code on success, FALSE otherwise.
 */
function locale_language_from_user($languages) {
  // User preference (only for logged users).
  global $user;

  if ($user->uid) {
    return $user->language;
  }

  // No language preference from the user.
  return FALSE;
}

/**
 * Identify language from a request/session parameter.
 *
 * @param $languages
 *   An array of valid language objects.
 *
 * @return
 *   A valid language code on success, FALSE otherwise.
 */
function locale_language_from_session($languages) {
  $param = variable_get('locale_language_negotiation_session_param', 'language');

  // Request parameter: we need to update the session parameter only if we have
  // an authenticated user.
  if (isset($_GET[$param]) && isset($languages[$langcode = $_GET[$param]])) {
    global $user;
    if ($user->uid) {
      $_SESSION[$param] = $langcode;
    }
    return $langcode;
  }

  // Session parameter.
  if (isset($_SESSION[$param])) {
    return $_SESSION[$param];
  }

  return FALSE;
}

/**
 * Identify language via URL prefix or domain.
 *
 * @param $languages
 *   An array of valid language objects.
 *
 * @return
 *   A valid language code on success, FALSE otherwise.
 */
function locale_language_from_url($languages) {
  $language_url = FALSE;

  if (!language_negotiation_get_any(LOCALE_LANGUAGE_NEGOTIATION_URL)) {
    return $language_url;
  }

  switch (variable_get('locale_language_negotiation_url_part', LOCALE_LANGUAGE_NEGOTIATION_URL_PREFIX)) {
    case LOCALE_LANGUAGE_NEGOTIATION_URL_PREFIX:
      // $_GET['q'] might not be available at this time, because
      // path initialization runs after the language bootstrap phase.
      list($language, $_GET['q']) = language_url_split_prefix(isset($_GET['q']) ? $_GET['q'] : NULL, $languages);
      if ($language !== FALSE) {
        $language_url = $language->language;
      }
      break;

    case LOCALE_LANGUAGE_NEGOTIATION_URL_DOMAIN:
      foreach ($languages as $language) {
        // Skip check if the language doesn't have a domain.
        if ($language->domain) {
          // Only compare the domains not the protocols or ports.
          // Remove protocol and add http:// so parse_url works
          $host = 'http://' . str_replace(array('http://', 'https://'), '', $language->domain);
          $host = parse_url($host, PHP_URL_HOST);
          if ($_SERVER['HTTP_HOST'] == $host) {
            $language_url = $language->language;
            break;
          }
        }
      }
      break;
  }

  return $language_url;
}

/**
 * Determines the language to be assigned to URLs when none is detected.
 *
 * The language negotiation process has a fallback chain that ends with the
 * default language provider. Each built-in language type has a separate
 * initialization:
 * - Interface language, which is the only configurable one, always gets a valid
 *   value. If no request-specific language is detected, the default language
 *   will be used.
 * - Content language merely inherits the interface language by default.
 * - URL language is detected from the requested URL and will be used to rewrite
 *   URLs appearing in the page being rendered. If no language can be detected,
 *   there are two possibilities:
 *   - If the default language has no configured path prefix or domain, then the
 *     default language is used. This guarantees that (missing) URL prefixes are
 *     preserved when navigating through the site.
 *   - If the default language has a configured path prefix or domain, a
 *     requested URL having an empty prefix or domain is an anomaly that must be
 *     fixed. This is done by introducing a prefix or domain in the rendered
 *     page matching the detected interface language.
 *
 * @param $languages
 *   (optional) An array of valid language objects. This is passed by
 *   language_provider_invoke() to every language provider callback, but it is
 *   not actually needed here. Defaults to NULL.
 * @param $language_type
 *   (optional) The language type to fall back to. Defaults to the interface
 *   language.
 *
 * @return
 *   A valid language code.
 */
function locale_language_url_fallback($language = NULL, $language_type = LANGUAGE_TYPE_INTERFACE) {
  $default = language_default();
  $prefix = (variable_get('locale_language_negotiation_url_part', LOCALE_LANGUAGE_NEGOTIATION_URL_PREFIX) == LOCALE_LANGUAGE_NEGOTIATION_URL_PREFIX);

  // If the default language is not configured to convey language information,
  // a missing URL language information indicates that URL language should be
  // the default one, otherwise we fall back to an already detected language.
  if (($prefix && empty($default->prefix)) || (!$prefix && empty($default->domain))) {
    return $default->language;
  }
  else {
    return $GLOBALS[$language_type]->language;
  }
}

/**
 * Return the URL language switcher block. Translation links may be provided by
 * other modules.
 */
function locale_language_switcher_url($type, $path) {
  $languages = language_list('enabled');
  $links = array();

  foreach ($languages[1] as $language) {
    $links[$language->language] = array(
      'href'       => $path,
      'title'      => $language->native,
      'language'   => $language,
      'attributes' => array('class' => array('language-link')),
    );
  }

  return $links;
}

/**
 * Return the session language switcher block.
 */
function locale_language_switcher_session($type, $path) {
  drupal_add_css(drupal_get_path('module', 'locale') . '/locale.css');

  $param = variable_get('locale_language_negotiation_session_param', 'language');
  $language_query = isset($_SESSION[$param]) ? $_SESSION[$param] : $GLOBALS[$type]->language;

  $languages = language_list('enabled');
  $links = array();

  $query = $_GET;
  unset($query['q']);

  foreach ($languages[1] as $language) {
    $langcode = $language->language;
    $links[$langcode] = array(
      'href'       => $path,
      'title'      => $language->native,
      'attributes' => array('class' => array('language-link')),
      'query'      => $query,
    );
    if ($language_query != $langcode) {
      $links[$langcode]['query'][$param] = $langcode;
    }
    else {
      $links[$langcode]['attributes']['class'][] = ' session-active';
    }
  }

  return $links;
}

/**
 * Rewrite URLs for the URL language provider.
 */
function locale_language_url_rewrite_url(&$path, &$options) {
  static $drupal_static_fast;
  if (!isset($drupal_static_fast)) {
    $drupal_static_fast['languages'] = &drupal_static(__FUNCTION__);
  }
  $languages = &$drupal_static_fast['languages'];

  if (!isset($languages)) {
    $languages = language_list('enabled');
    $languages = array_flip(array_keys($languages[1]));
  }

  // Language can be passed as an option, or we go for current URL language.
  if (!isset($options['language'])) {
    global $language_url;
    $options['language'] = $language_url;
  }
  // We allow only enabled languages here.
  elseif (!isset($languages[$options['language']->language])) {
    unset($options['language']);
    return;
  }

  if (isset($options['language'])) {
    switch (variable_get('locale_language_negotiation_url_part', LOCALE_LANGUAGE_NEGOTIATION_URL_PREFIX)) {
      case LOCALE_LANGUAGE_NEGOTIATION_URL_DOMAIN:
        if ($options['language']->domain) {
          // Ask for an absolute URL with our modified base_url.
          $options['absolute'] = TRUE;
          $options['base_url'] = $options['language']->domain;
        }
        break;

      case LOCALE_LANGUAGE_NEGOTIATION_URL_PREFIX:
        if (!empty($options['language']->prefix)) {
          $options['prefix'] = $options['language']->prefix . '/';
        }
        break;
    }
  }
}

/**
 * Rewrite URLs for the Session language provider.
 */
function locale_language_url_rewrite_session(&$path, &$options) {
  static $query_rewrite, $query_param, $query_value;

  // The following values are not supposed to change during a single page
  // request processing.
  if (!isset($query_rewrite)) {
    global $user;
    if (!$user->uid) {
      $languages = language_list('enabled');
      $languages = $languages[1];
      $query_param = check_plain(variable_get('locale_language_negotiation_session_param', 'language'));
      $query_value = isset($_GET[$query_param]) ? check_plain($_GET[$query_param]) : NULL;
      $query_rewrite = isset($languages[$query_value]) && language_negotiation_get_any(LOCALE_LANGUAGE_NEGOTIATION_SESSION);
    }
    else {
      $query_rewrite = FALSE;
    }
  }

  // If the user is anonymous, the user language provider is enabled, and the
  // corresponding option has been set, we must preserve any explicit user
  // language preference even with cookies disabled.
  if ($query_rewrite) {
    if (is_string($options['query'])) {
      $options['query'] = drupal_get_query_array($options['query']);
    }
    if (!isset($options['query'][$query_param])) {
      $options['query'][$query_param] = $query_value;
    }
  }
}

/**
 * @} End of "locale-languages-negotiation"
 */

/**
 * 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')));
}

/**
 * @defgroup locale-api-add Language addition API
 * @{
 * Add a language.
 *
 * The language addition API is used to create languages and store them.
 */

/**
 * API function to add a language.
 *
 * @param $langcode
 *   Language code.
 * @param $name
 *   English name of the language
 * @param $native
 *   Native name of the language
 * @param $direction
 *   LANGUAGE_LTR or LANGUAGE_RTL
 * @param $domain
 *   Optional custom domain name with protocol, without
 *   trailing slash (eg. http://de.example.com).
 * @param $prefix
 *   Optional path prefix for the language. Defaults to the
 *   language code if omitted.
 * @param $enabled
 *   Optionally TRUE to enable the language when created or FALSE to disable.
 * @param $default
 *   Optionally set this language to be the default.
 */
function locale_add_language($langcode, $name = NULL, $native = NULL, $direction = LANGUAGE_LTR, $domain = '', $prefix = '', $enabled = TRUE, $default = FALSE) {
  // Default prefix on language code.
  if (empty($prefix)) {
    $prefix = $langcode;
  }

  // If name was not set, we add a predefined language.
  if (!isset($name)) {
    include_once DRUPAL_ROOT . '/includes/iso.inc';
    $predefined = _locale_get_predefined_list();
    $name = $predefined[$langcode][0];
    $native = isset($predefined[$langcode][1]) ? $predefined[$langcode][1] : $predefined[$langcode][0];
    $direction = isset($predefined[$langcode][2]) ? $predefined[$langcode][2] : LANGUAGE_LTR;
  }

  db_insert('languages')
    ->fields(array(
      'language' => $langcode,
      'name' => $name,
      'native' => $native,
      'direction' => $direction,
      'domain' => $domain,
      'prefix' => $prefix,
      'enabled' => $enabled,
    ))
    ->execute();

  // Only set it as default if enabled.
  if ($enabled && $default) {
    variable_set('language_default', (object) array('language' => $langcode, 'name' => $name, 'native' => $native, 'direction' => $direction, 'enabled' => (int) $enabled, 'plurals' => 0, 'formula' => '', 'domain' => '', 'prefix' => $prefix, 'weight' => 0, 'javascript' => ''));
  }

  if ($enabled) {
    // Increment enabled language count if we are adding an enabled language.
    variable_set('language_count', variable_get('language_count', 1) + 1);
  }

  // Kill the static cache in language_list().
  drupal_static_reset('language_list');

  // Force JavaScript translation file creation for the newly added language.
  _locale_invalidate_js($langcode);

  watchdog('locale', 'The %language language (%code) has been created.', array('%language' => $name, '%code' => $langcode));

  module_invoke_all('multilingual_settings_changed');
}
/**
 * @} End of "locale-api-add"
 */

/**
 * @defgroup locale-api-import-export Translation import/export API.
 * @{
 * Functions to import and export translations.
 *
 * These functions provide the ability to import translations from
 * external files and to export translations and translation templates.
 */

/**
 * Parses Gettext Portable Object file information and inserts into database
 *
 * @param $file
 *   Drupal file object corresponding to the PO file to import.
 * @param $langcode
 *   Language code.
 * @param $mode
 *   Should existing translations be replaced LOCALE_IMPORT_KEEP or
 *   LOCALE_IMPORT_OVERWRITE.
 * @param $group
 *   Text group to import PO file into (eg. 'default' for interface
 *   translations).
 */
function _locale_import_po($file, $langcode, $mode, $group = NULL) {
  // Try to allocate enough time to parse and import the data.
  drupal_set_time_limit(240);

  // Check if we have the language already in the database.
  if (!db_query("SELECT COUNT(language) FROM {languages} WHERE language = :language", array(':language' => $langcode))->fetchField()) {
    drupal_set_message(t('The language selected for import is not supported.'), 'error');
    return FALSE;
  }

  // Get strings from file (returns on failure after a partial import, or on success)
  $status = _locale_import_read_po('db-store', $file, $mode, $langcode, $group);
  if ($status === FALSE) {
    // Error messages are set in _locale_import_read_po().
    return FALSE;
  }

  // Get status information on import process.
  list($header_done, $additions, $updates, $deletes, $skips) = _locale_import_one_string('db-report');

  if (!$header_done) {
    drupal_set_message(t('The translation file %filename appears to have a missing or malformed header.', array('%filename' => $file->filename)), 'error');
  }

  // Clear cache and force refresh of JavaScript translations.
  _locale_invalidate_js($langcode);
  cache_clear_all('locale:', 'cache', TRUE);

  // Rebuild the menu, strings may have changed.
  menu_rebuild();

  drupal_set_message(t('The translation was successfully imported. There are %number newly created translated strings, %update strings were updated and %delete strings were removed.', array('%number' => $additions, '%update' => $updates, '%delete' => $deletes)));
  watchdog('locale', 'Imported %file into %locale: %number new strings added, %update updated and %delete removed.', array('%file' => $file->filename, '%locale' => $langcode, '%number' => $additions, '%update' => $updates, '%delete' => $deletes));
  if ($skips) {
    $skip_message = format_plural($skips, 'One translation string was skipped because it contains disallowed HTML.', '@count translation strings were skipped because they contain disallowed HTML.');
    drupal_set_message($skip_message);
    watchdog('locale', '@count disallowed HTML string(s) in %file', array('@count' => $skips, '%file' => $file->uri), WATCHDOG_WARNING);
  }
  return TRUE;
}

/**
 * Parses Gettext Portable Object file into an array
 *
 * @param $op
 *   Storage operation type: db-store or mem-store.
 * @param $file
 *   Drupal file object corresponding to the PO file to import.
 * @param $mode
 *   Should existing translations be replaced LOCALE_IMPORT_KEEP or
 *   LOCALE_IMPORT_OVERWRITE.
 * @param $lang
 *   Language code.
 * @param $group
 *   Text group to import PO file into (eg. 'default' for interface
 *   translations).
 */
function _locale_import_read_po($op, $file, $mode = NULL, $lang = NULL, $group = 'default') {

  // The file will get closed by PHP on returning from this function.
  $fd = fopen($file->uri, 'rb');
  if (!$fd) {
    _locale_import_message('The translation import failed, because the file %filename could not be read.', $file);
    return FALSE;
  }

  /*
   * The parser context. Can be:
   *  - 'COMMENT' (#)
   *  - 'MSGID' (msgid)
   *  - 'MSGID_PLURAL' (msgid_plural)
   *  - 'MSGCTXT' (msgctxt)
   *  - 'MSGSTR' (msgstr or msgstr[])
   *  - 'MSGSTR_ARR' (msgstr_arg)
   */
  $context = 'COMMENT';

  // Current entry being read.
  $current = array();

  // Current plurality for 'msgstr[]'.
  $plural = 0;

  // Current line.
  $lineno = 0;

  while (!feof($fd)) {
    // A line should not be longer than 10 * 1024.
    $line = fgets($fd, 10 * 1024);

    if ($lineno == 0) {
      // The first line might come with a UTF-8 BOM, which should be removed.
      $line = str_replace("\xEF\xBB\xBF", '', $line);
    }

    $lineno++;

    // Trim away the linefeed.
    $line = trim(strtr($line, array("\\\n" => "")));

    if (!strncmp('#', $line, 1)) {
      // Lines starting with '#' are comments.

      if ($context == 'COMMENT') {
        // Already in comment token, insert the comment.
        $current['#'][] = substr($line, 1);
      }
      elseif (($context == 'MSGSTR') || ($context == 'MSGSTR_ARR')) {
        // We are currently in string token, close it out.
        _locale_import_one_string($op, $current, $mode, $lang, $file, $group);

        // Start a new entry for the comment.
        $current         = array();
        $current['#'][]  = substr($line, 1);

        $context = 'COMMENT';
      }
      else {
        // A comment following any other token is a syntax error.
        _locale_import_message('The translation file %filename contains an error: "msgstr" was expected but not found on line %line.', $file, $lineno);
        return FALSE;
      }
    }
    elseif (!strncmp('msgid_plural', $line, 12)) {
      // A plural form for the current message.

      if ($context != 'MSGID') {
        // A plural form cannot be added to anything else but the id directly.
        _locale_import_message('The translation file %filename contains an error: "msgid_plural" was expected but not found on line %line.', $file, $lineno);
        return FALSE;
      }

      // Remove 'msgid_plural' and trim away whitespace.
      $line = trim(substr($line, 12));
      // At this point, $line should now contain only the plural form.

      $quoted = _locale_import_parse_quoted($line);
      if ($quoted === FALSE) {
        // The plural form must be wrapped in quotes.
        _locale_import_message('The translation file %filename contains a syntax error on line %line.', $file, $lineno);
        return FALSE;
      }

      // Append the plural form to the current entry.
      $current['msgid'] .= "\0" . $quoted;

      $context = 'MSGID_PLURAL';
    }
    elseif (!strncmp('msgid', $line, 5)) {
      // Starting a new message.

      if (($context == 'MSGSTR') || ($context == 'MSGSTR_ARR')) {
        // We are currently in a message string, close it out.
        _locale_import_one_string($op, $current, $mode, $lang, $file, $group);

        // Start a new context for the id.
        $current = array();
      }
      elseif ($context == 'MSGID') {
        // We are currently already in the context, meaning we passed an id with no data.
        _locale_import_message('The translation file %filename contains an error: "msgid" is unexpected on line %line.', $file, $lineno);
        return FALSE;
      }

      // Remove 'msgid' and trim away whitespace.
      $line = trim(substr($line, 5));
      // At this point, $line should now contain only the message id.

      $quoted = _locale_import_parse_quoted($line);
      if ($quoted === FALSE) {
        // The message id must be wrapped in quotes.
        _locale_import_message('The translation file %filename contains a syntax error on line %line.', $file, $lineno);
        return FALSE;
      }

      $current['msgid'] = $quoted;
      $context = 'MSGID';
    }
    elseif (!strncmp('msgctxt', $line, 7)) {
      // Starting a new context.

      if (($context == 'MSGSTR') || ($context == 'MSGSTR_ARR')) {
        // We are currently in a message, start a new one.
        _locale_import_one_string($op, $current, $mode, $lang, $file, $group);
        $current = array();
      }
      elseif (!empty($current['msgctxt'])) {
        // A context cannot apply to another context.
        _locale_import_message('The translation file %filename contains an error: "msgctxt" is unexpected on line %line.', $file, $lineno);
        return FALSE;
      }

      // Remove 'msgctxt' and trim away whitespaces.
      $line = trim(substr($line, 7));
      // At this point, $line should now contain the context.

      $quoted = _locale_import_parse_quoted($line);
      if ($quoted === FALSE) {
        // The context string must be quoted.
        _locale_import_message('The translation file %filename contains a syntax error on line %line.', $file, $lineno);
        return FALSE;
      }

      $current['msgctxt'] = $quoted;

      $context = 'MSGCTXT';
    }
    elseif (!strncmp('msgstr[', $line, 7)) {
      // A message string for a specific plurality.

      if (($context != 'MSGID') && ($context != 'MSGCTXT') && ($context != 'MSGID_PLURAL') && ($context != 'MSGSTR_ARR')) {
        // Message strings must come after msgid, msgxtxt, msgid_plural, or other msgstr[] entries.
        _locale_import_message('The translation file %filename contains an error: "msgstr[]" is unexpected on line %line.', $file, $lineno);
        return FALSE;
      }

      // Ensure the plurality is terminated.
      if (strpos($line, ']') === FALSE) {
        _locale_import_message('The translation file %filename contains a syntax error on line %line.', $file, $lineno);
        return FALSE;
      }

      // Extract the plurality.
      $frombracket = strstr($line, '[');
      $plural = substr($frombracket, 1, strpos($frombracket, ']') - 1);

      // Skip to the next whitespace and trim away any further whitespace, bringing $line to the message data.
      $line = trim(strstr($line, " "));

      $quoted = _locale_import_parse_quoted($line);
      if ($quoted === FALSE) {
        // The string must be quoted.
        _locale_import_message('The translation file %filename contains a syntax error on line %line.', $file, $lineno);
        return FALSE;
      }

      $current['msgstr'][$plural] = $quoted;

      $context = 'MSGSTR_ARR';
    }
    elseif (!strncmp("msgstr", $line, 6)) {
      // A string for the an id or context.

      if (($context != 'MSGID') && ($context != 'MSGCTXT')) {
        // Strings are only valid within an id or context scope.
        _locale_import_message('The translation file %filename contains an error: "msgstr" is unexpected on line %line.', $file, $lineno);
        return FALSE;
      }

      // Remove 'msgstr' and trim away away whitespaces.
      $line = trim(substr($line, 6));
      // At this point, $line should now contain the message.

      $quoted = _locale_import_parse_quoted($line);
      if ($quoted === FALSE) {
        // The string must be quoted.
        _locale_import_message('The translation file %filename contains a syntax error on line %line.', $file, $lineno);
        return FALSE;
      }

      $current['msgstr'] = $quoted;

      $context = 'MSGSTR';
    }
    elseif ($line != '') {
      // Anything that is not a token may be a continuation of a previous token.

      $quoted = _locale_import_parse_quoted($line);
      if ($quoted === FALSE) {
        // The string must be quoted.
        _locale_import_message('The translation file %filename contains a syntax error on line %line.', $file, $lineno);
        return FALSE;
      }

      // Append the string to the current context.
      if (($context == 'MSGID') || ($context == 'MSGID_PLURAL')) {
        $current['msgid'] .= $quoted;
      }
      elseif ($context == 'MSGCTXT') {
        $current['msgctxt'] .= $quoted;
      }
      elseif ($context == 'MSGSTR') {
        $current['msgstr'] .= $quoted;
      }
      elseif ($context == 'MSGSTR_ARR') {
        $current['msgstr'][$plural] .= $quoted;
      }
      else {
        // No valid context to append to.
        _locale_import_message('The translation file %filename contains an error: there is an unexpected string on line %line.', $file, $lineno);
        return FALSE;
      }
    }
  }

  // End of PO file, closed out the last entry.
  if (($context == 'MSGSTR') || ($context == 'MSGSTR_ARR')) {
    _locale_import_one_string($op, $current, $mode, $lang, $file, $group);
  }
  elseif ($context != 'COMMENT') {
    _locale_import_message('The translation file %filename ended unexpectedly at line %line.', $file, $lineno);
    return FALSE;
  }
}

/**
 * Sets an error message occurred during locale file parsing.
 *
 * @param $message
 *   The message to be translated.
 * @param $file
 *   Drupal file object corresponding to the PO file to import.
 * @param $lineno
 *   An optional line number argument.
 */
function _locale_import_message($message, $file, $lineno = NULL) {
  $vars = array('%filename' => $file->filename);
  if (isset($lineno)) {
    $vars['%line'] = $lineno;
  }
  $t = get_t();
  drupal_set_message($t($message, $vars), 'error');
}

/**
 * Imports a string into the database
 *
 * @param $op
 *   Operation to perform: 'db-store', 'db-report', 'mem-store' or 'mem-report'.
 * @param $value
 *   Details of the string stored.
 * @param $mode
 *   Should existing translations be replaced LOCALE_IMPORT_KEEP or
 *   LOCALE_IMPORT_OVERWRITE.
 * @param $lang
 *   Language to store the string in.
 * @param $file
 *   Object representation of file being imported, only required when op is
 *   'db-store'.
 * @param $group
 *   Text group to import PO file into (eg. 'default' for interface
 *   translations).
 */
function _locale_import_one_string($op, $value = NULL, $mode = NULL, $lang = NULL, $file = NULL, $group = 'default') {
  $report = &drupal_static(__FUNCTION__, array('additions' => 0, 'updates' => 0, 'deletes' => 0, 'skips' => 0));
  $header_done = &drupal_static(__FUNCTION__ . ':header_done', FALSE);
  $strings = &drupal_static(__FUNCTION__ . ':strings', array());

  switch ($op) {
    // Return stored strings
    case 'mem-report':
      return $strings;

    // Store string in memory (only supports single strings)
    case 'mem-store':
      $strings[isset($value['msgctxt']) ? $value['msgctxt'] : ''][$value['msgid']] = $value['msgstr'];
      return;

    // Called at end of import to inform the user
    case 'db-report':
      return array($header_done, $report['additions'], $report['updates'], $report['deletes'], $report['skips']);

    // Store the string we got in the database.
    case 'db-store':
      // We got header information.
      if ($value['msgid'] == '') {
        $languages = language_list();
        if (($mode != LOCALE_IMPORT_KEEP) || empty($languages[$lang]->plurals)) {
          // Since we only need to parse the header if we ought to update the
          // plural formula, only run this if we don't need to keep existing
          // data untouched or if we don't have an existing plural formula.
          $header = _locale_import_parse_header($value['msgstr']);

          // Get the plural formula and update in database.
          if (isset($header["Plural-Forms"]) && $p = _locale_import_parse_plural_forms($header["Plural-Forms"], $file->uri)) {
            list($nplurals, $plural) = $p;
            db_update('languages')
              ->fields(array(
                'plurals' => $nplurals,
                'formula' => $plural,
              ))
              ->condition('language', $lang)
              ->execute();
          }
          else {
            db_update('languages')
              ->fields(array(
                'plurals' => 0,
                'formula' => '',
              ))
              ->condition('language', $lang)
              ->execute();
          }