diff --git a/core/includes/gettext.inc b/core/includes/gettext.inc
deleted file mode 100644
index ef9d25d0dc06d05a0df65137fb094c6d7266c365..0000000000000000000000000000000000000000
--- a/core/includes/gettext.inc
+++ /dev/null
@@ -1,1131 +0,0 @@
-<?php
-
-/**
- * @file
- * Gettext parsing and generating API.
- *
- * @todo Decouple these functions from Locale API and put to gettext_ namespace.
- */
-
-/**
- * @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 information and inserts it into the database.
- *
- * @param $file
- *   Drupal file object corresponding to the PO file to import.
- * @param $langcode
- *   Language code.
- * @param $overwrite_options
- *   An associative array indicating what data should be overwritten, if any.
- *   - not_customized: strings marked not customized should be overwritten.
- *   - customized: strings marked customized should be overwritten.
- * @param $customized
- *   Whether the strings being imported should be saved as customized.
- *   Use LOCALE_CUSTOMIZED or LOCALE_NOT_CUSTOMIZED. All strings in the file
- *   will be saved with this customization flag.
- */
-function _locale_import_po($file, $langcode, $overwrite_options, $customized = LOCALE_NOT_CUSTOMIZED) {
-  // Try to allocate enough time to parse and import the data.
-  drupal_set_time_limit(240);
-
-  // Check if we have the language already in the database.
-  if (!language_load($langcode)) {
-    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, $overwrite_options, $langcode, $customized);
-  if ($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()->deletePrefix('locale:');
-
-  // Rebuild the menu, strings may have changed.
-  menu_router_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) {
-    if (module_exists('dblog')) {
-      $skip_message = format_plural($skips, 'A translation string was skipped because of disallowed or malformed HTML. <a href="@url">See the log</a> for details.', '@count translation strings were skipped because of disallowed or malformed HTML. <a href="@url">See the log</a> for details.', array('@url' => url('admin/reports/dblog')));
-    }
-    else {
-      $skip_message = format_plural($skips, 'A translation string was skipped because of disallowed or malformed HTML. See the log for details.', '@count translation strings were skipped because of disallowed or malformed HTML. See the log for details.');
-    }
-    drupal_set_message($skip_message, 'error');
-    watchdog('locale', '@count disallowed HTML string(s) in %file', array('@count' => $skips, '%file' => $file->uri), WATCHDOG_WARNING);
-  }
-  return TRUE;
-}
-
-/**
- * Parses a 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 $overwrite_options
- *   An associative array indicating what data should be overwritten, if any.
- *   - not_customized: not customized strings should be overwritten.
- *   - customized: customized strings should be overwritten.
- * @param $lang
- *   Language code.
- * @param $customized
- *   Whether the strings being imported should be saved as customized.
- *   Use LOCALE_CUSTOMIZED or LOCALE_NOT_CUSTOMIZED.
- */
-function _locale_import_read_po($op, $file, $overwrite_options = NULL, $lang = NULL, $customized = LOCALE_NOT_CUSTOMIZED) {
-
-  // 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, $overwrite_options, $lang, $file, $customized);
-
-        // 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'] .= LOCALE_PLURAL_DELIMITER . $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, $overwrite_options, $lang, $file, $customized);
-
-        // 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, $overwrite_options, $lang, $file, $customized);
-        $current = array();
-      }
-      elseif (!empty($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, $overwrite_options, $lang, $file, $customized);
-  }
-  elseif ($context != 'COMMENT') {
-    _locale_import_message('The translation file %filename ended unexpectedly at line %line.', $file, $lineno);
-    return FALSE;
-  }
-}
-
-/**
- * Sets an error message if an error 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');
-}
-
-/**
- * Performs the specified operation for one string.
- *
- * @param $op
- *   Operation to perform: 'db-store', 'db-report', 'mem-store' or 'mem-report'.
- * @param $value
- *   Details of the string stored.
- * @param $overwrite_options
- *   An associative array indicating what data should be overwritten, if any.
- *   - not_customized: not customized strings should be overwritten.
- *   - customized: customized strings should be overwritten.
- * @param $lang
- *   Language to store the string in.
- * @param $file
- *   Object representation of file being imported, only required when op is
- *   'db-store'.
- * @param $customized
- *   Whether the strings being imported should be saved as customized.
- *   Use LOCALE_CUSTOMIZED or LOCALE_NOT_CUSTOMIZED.
- */
-function _locale_import_one_string($op, $value = NULL, $overwrite_options = NULL, $lang = NULL, $file = NULL, $customized = LOCALE_NOT_CUSTOMIZED) {
-  $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'], $report['skips']);
-
-    // Store the string we got in the database.
-    case 'db-store':
-
-      if ($value['msgid'] == '') {
-        // If 'msgid' is empty, it means we got values for the header of the
-        // file as per the structure of the Gettext format.
-        $locale_plurals = variable_get('locale_translation_plurals', array());
-        if (array_sum($overwrite_options) || empty($locale_plurals[$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 and store the plural formula if available.
-          if (isset($header["Plural-Forms"]) && $p = _locale_import_parse_plural_forms($header["Plural-Forms"], $file->uri)) {
-            list($nplurals, $formula) = $p;
-            $locale_plurals[$lang] = array(
-              'plurals' => $nplurals,
-              'formula' => $formula,
-            );
-            variable_set('locale_translation_plurals', $locale_plurals);
-          }
-        }
-        $header_done = TRUE;
-      }
-
-      else {
-        // Found a string to store, clean up and prepare the data.
-        $comments = _locale_import_shorten_comments(empty($value['#']) ? array() : $value['#']);
-
-        if (is_array($value['msgstr'])) {
-          // Sort plural variants by their form index.
-          ksort($value['msgstr']);
-          // Serialize plural variants in one string by LOCALE_PLURAL_DELIMITER.
-          $value['msgstr'] = implode(LOCALE_PLURAL_DELIMITER, $value['msgstr']);
-        }
-
-        _locale_import_one_string_db(
-          $report,
-          $lang,
-          isset($value['msgctxt']) ? $value['msgctxt'] : '',
-          $value['msgid'],
-          $value['msgstr'],
-          $comments,
-          $overwrite_options,
-          $customized
-        );
-      }
-  } // end of db-store operation
-}
-
-/**
- * Imports one string into the database.
- *
- * @param $report
- *   Report array summarizing the number of changes done in the form:
- *   array(inserts, updates, deletes).
- * @param $langcode
- *   Language code to import string into.
- * @param $context
- *   The context of this string.
- * @param $source
- *   Source string.
- * @param $translation
- *   Translation to language specified in $langcode.
- * @param $location
- *   Location value to save with source string.
- * @param $overwrite_options
- *   An associative array indicating what data should be overwritten, if any.
- *   - not_customized: not customized strings should be overwritten.
- *   - customized: customized strings should be overwritten.
- * @param $customized
- *   (optional) Whether the strings being imported should be saved as customized.
- *   Use LOCALE_CUSTOMIZED or LOCALE_NOT_CUSTOMIZED.
- *
- * @return
- *   The string ID of the existing string modified or the new string added.
- */
-function _locale_import_one_string_db(&$report, $langcode, $context, $source, $translation, $location, $overwrite_options, $customized = LOCALE_NOT_CUSTOMIZED) {
-
-  // Initialize overwrite options if not set.
-  $overwrite_options += array(
-    'not_customized' => FALSE,
-    'customized' => FALSE,
-  );
-
-  // Look up the source string and any existing translation.
-  $string = db_query("SELECT s.lid, t.customized 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", array(
-    ':source' => $source,
-    ':context' => $context,
-    ':language' => $langcode,
-    ))
-    ->fetchObject();
-
-  if (!empty($translation)) {
-    // Skip this string unless it passes a check for dangerous code.
-    if (!locale_string_is_safe($translation)) {
-      watchdog('locale', 'Import of string "%string" was skipped because of disallowed or malformed HTML.', array('%string' => $translation), WATCHDOG_ERROR);
-      $report['skips']++;
-      return 0;
-    }
-    elseif (isset($string->lid)) {
-      // We have this source string saved already.
-      db_update('locales_source')
-        ->fields(array(
-          'location' => $location,
-        ))
-        ->condition('lid', $string->lid)
-        ->execute();
-
-      if (!isset($string->customized)) {
-        // No translation in this language.
-        db_insert('locales_target')
-          ->fields(array(
-            'lid' => $string->lid,
-            'language' => $langcode,
-            'translation' => $translation,
-            'customized' => $customized,
-          ))
-          ->execute();
-
-        $report['additions']++;
-      }
-      elseif ($overwrite_options[$string->customized ? 'customized' : 'not_customized']) {
-        // Translation exists, only overwrite if instructed.
-        db_update('locales_target')
-          ->fields(array(
-            'translation' => $translation,
-            'customized' => $customized,
-          ))
-          ->condition('language', $langcode)
-          ->condition('lid', $string->lid)
-          ->execute();
-
-        $report['updates']++;
-      }
-      return $string->lid;
-    }
-    else {
-      // No such source string in the database yet.
-      $lid = db_insert('locales_source')
-        ->fields(array(
-          'location' => $location,
-          'source' => $source,
-          'context' => (string) $context,
-        ))
-        ->execute();
-
-      db_insert('locales_target')
-        ->fields(array(
-           'lid' => $lid,
-           'language' => $langcode,
-           'translation' => $translation,
-           'customized' => $customized,
-        ))
-        ->execute();
-
-      $report['additions']++;
-      return $lid;
-    }
-  }
-  elseif (isset($string->lid) && isset($string->customized) && $overwrite_options[$string->customized ? 'customized' : 'not_customized']) {
-    // Empty translation, remove existing if instructed.
-    db_delete('locales_target')
-      ->condition('language', $langcode)
-      ->condition('lid', $string->lid)
-      ->execute();
-
-    $report['deletes']++;
-    return $string->lid;
-  }
-}
-
-/**
- * Parses a Gettext Portable Object file header.
- *
- * @param $header
- *   A string containing the complete header.
- *
- * @return
- *   An associative array of key-value pairs.
- */
-function _locale_import_parse_header($header) {
-  $header_parsed = array();
-  $lines = array_map('trim', explode("\n", $header));
-  foreach ($lines as $line) {
-    if ($line) {
-      list($tag, $contents) = explode(":", $line, 2);
-      $header_parsed[trim($tag)] = trim($contents);
-    }
-  }
-  return $header_parsed;
-}
-
-/**
- * Parses a Plural-Forms entry from a Gettext Portable Object file header.
- *
- * @param $pluralforms
- *   A string containing the Plural-Forms entry.
- * @param $filepath
- *   A string containing the filepath.
- *
- * @return
- *   An array containing the number of plurals and a
- *   formula in PHP for computing the plural form.
- */
-function _locale_import_parse_plural_forms($pluralforms, $filepath) {
-  // First, delete all whitespace
-  $pluralforms = strtr($pluralforms, array(" " => "", "\t" => ""));
-
-  // Select the parts that define nplurals and plural
-  $nplurals = strstr($pluralforms, "nplurals=");
-  if (strpos($nplurals, ";")) {
-    $nplurals = substr($nplurals, 9, strpos($nplurals, ";") - 9);
-  }
-  else {
-    return FALSE;
-  }
-  $plural = strstr($pluralforms, "plural=");
-  if (strpos($plural, ";")) {
-    $plural = substr($plural, 7, strpos($plural, ";") - 7);
-  }
-  else {
-    return FALSE;
-  }
-
-  // Get PHP version of the plural formula
-  $plural = _locale_import_parse_arithmetic($plural);
-
-  if ($plural !== FALSE) {
-    return array($nplurals, $plural);
-  }
-  else {
-    drupal_set_message(t('The translation file %filepath contains an error: the plural formula could not be parsed.', array('%filepath' => $filepath)), 'error');
-    return FALSE;
-  }
-}
-
-/**
- * Parses and sanitizes an arithmetic formula into a PHP expression.
- *
- * While parsing, we ensure, that the operators have the right
- * precedence and associativity.
- *
- * @param $string
- *   A string containing the arithmetic formula.
- *
- * @return
- *   The PHP version of the formula.
- */
-function _locale_import_parse_arithmetic($string) {
-  // Operator precedence table
-  $precedence = array("(" => -1, ")" => -1, "?" => 1, ":" => 1, "||" => 3, "&&" => 4, "==" => 5, "!=" => 5, "<" => 6, ">" => 6, "<=" => 6, ">=" => 6, "+" => 7, "-" => 7, "*" => 8, "/" => 8, "%" => 8);
-  // Right associativity
-  $right_associativity = array("?" => 1, ":" => 1);
-
-  $tokens = _locale_import_tokenize_formula($string);
-
-  // Parse by converting into infix notation then back into postfix
-  // Operator stack - holds math operators and symbols
-  $operator_stack = array();
-  // Element Stack - holds data to be operated on
-  $element_stack = array();
-
-  foreach ($tokens as $token) {
-    $current_token = $token;
-
-    // Numbers and the $n variable are simply pushed into $element_stack
-    if (is_numeric($token)) {
-      $element_stack[] = $current_token;
-    }
-    elseif ($current_token == "n") {
-      $element_stack[] = '$n';
-    }
-    elseif ($current_token == "(") {
-      $operator_stack[] = $current_token;
-    }
-    elseif ($current_token == ")") {
-      $topop = array_pop($operator_stack);
-      while (isset($topop) && ($topop != "(")) {
-        $element_stack[] = $topop;
-        $topop = array_pop($operator_stack);
-      }
-    }
-    elseif (!empty($precedence[$current_token])) {
-      // If it's an operator, then pop from $operator_stack into $element_stack until the
-      // precedence in $operator_stack is less than current, then push into $operator_stack
-      $topop = array_pop($operator_stack);
-      while (isset($topop) && ($precedence[$topop] >= $precedence[$current_token]) && !(($precedence[$topop] == $precedence[$current_token]) && !empty($right_associativity[$topop]) && !empty($right_associativity[$current_token]))) {
-        $element_stack[] = $topop;
-        $topop = array_pop($operator_stack);
-      }
-      if ($topop) {
-        $operator_stack[] = $topop;   // Return element to top
-      }
-      $operator_stack[] = $current_token;      // Parentheses are not needed
-    }
-    else {
-      return FALSE;
-    }
-  }
-
-  // Flush operator stack
-  $topop = array_pop($operator_stack);
-  while ($topop != NULL) {
-    $element_stack[] = $topop;
-    $topop = array_pop($operator_stack);
-  }
-
-  // Now extract formula from stack
-  $previous_size = count($element_stack) + 1;
-  while (count($element_stack) < $previous_size) {
-    $previous_size = count($element_stack);
-    for ($i = 2; $i < count($element_stack); $i++) {
-      $op = $element_stack[$i];
-      if (!empty($precedence[$op])) {
-        $f = "";
-        if ($op == ":") {
-          $f = $element_stack[$i - 2] . "):" . $element_stack[$i - 1] . ")";
-        }
-        elseif ($op == "?") {
-          $f = "(" . $element_stack[$i - 2] . "?(" . $element_stack[$i - 1];
-        }
-        else {
-          $f = "(" . $element_stack[$i - 2] . $op . $element_stack[$i - 1] . ")";
-        }
-        array_splice($element_stack, $i - 2, 3, $f);
-        break;
-      }
-    }
-  }
-
-  // If only one element is left, the number of operators is appropriate
-  if (count($element_stack) == 1) {
-    return $element_stack[0];
-  }
-  else {
-    return FALSE;
-  }
-}
-
-/**
- * Provides backward-compatible formula parsing for token_get_all().
- *
- * @param $string
- *   A string containing the arithmetic formula.
- *
- * @return
- *   The PHP version of the formula.
- */
-function _locale_import_tokenize_formula($formula) {
-  $formula = str_replace(" ", "", $formula);
-  $tokens = array();
-  for ($i = 0; $i < strlen($formula); $i++) {
-    if (is_numeric($formula[$i])) {
-      $num = $formula[$i];
-      $j = $i + 1;
-      while ($j < strlen($formula) && is_numeric($formula[$j])) {
-        $num .= $formula[$j];
-        $j++;
-      }
-      $i = $j - 1;
-      $tokens[] = $num;
-    }
-    elseif ($pos = strpos(" =<>!&|", $formula[$i])) { // We won't have a space
-      $next = $formula[$i + 1];
-      switch ($pos) {
-        case 1:
-        case 2:
-        case 3:
-        case 4:
-          if ($next == '=') {
-            $tokens[] = $formula[$i] . '=';
-            $i++;
-          }
-          else {
-            $tokens[] = $formula[$i];
-          }
-          break;
-        case 5:
-          if ($next == '&') {
-            $tokens[] = '&&';
-            $i++;
-          }
-          else {
-            $tokens[] = $formula[$i];
-          }
-          break;
-        case 6:
-          if ($next == '|') {
-            $tokens[] = '||';
-            $i++;
-          }
-          else {
-            $tokens[] = $formula[$i];
-          }
-          break;
-      }
-    }
-    else {
-      $tokens[] = $formula[$i];
-    }
-  }
-  return $tokens;
-}
-
-/**
- * Generates a short, one-string version of the passed comment array.
- *
- * @param $comment
- *   An array of strings containing a comment.
- *
- * @return
- *   Short one-string version of the comment.
- */
-function _locale_import_shorten_comments($comment) {
-  $comm = '';
-  while (count($comment)) {
-    $test = $comm . substr(array_shift($comment), 1) . ', ';
-    if (strlen($comm) < 130) {
-      $comm = $test;
-    }
-    else {
-      break;
-    }
-  }
-  return trim(substr($comm, 0, -2));
-}
-
-/**
- * Parses a string in quotes.
- *
- * @param $string
- *   A string specified with enclosing quotes.
- *
- * @return
- *   The string parsed from inside the quotes.
- */
-function _locale_import_parse_quoted($string) {
-  if (substr($string, 0, 1) != substr($string, -1, 1)) {
-    return FALSE;   // Start and end quotes must be the same
-  }
-  $quote = substr($string, 0, 1);
-  $string = substr($string, 1, -1);
-  if ($quote == '"') {        // Double quotes: strip slashes
-    return stripcslashes($string);
-  }
-  elseif ($quote == "'") {  // Simple quote: return as-is
-    return $string;
-  }
-  else {
-    return FALSE;             // Unrecognized quote
-  }
-}
-
-/**
- * Generates a structured array of all translated strings for the language.
- *
- * @param $language
- *   Language object to generate the output for, or NULL if generating
- *   translation template.
- * @param $options
- *   (optional) An associative array specifying what to include in the output:
- *   - customized: include customized strings (if TRUE)
- *   - uncustomized: include non-customized string (if TRUE)
- *   - untranslated: include untranslated source strings (if TRUE)
- *   Ignored if $language is NULL.
- *
- * @return
- *   An array of translated strings that can be used to generate an export.
- */
-function _locale_export_get_strings($language = NULL, $options = array()) {
-
-  // Assume FALSE for all options if not provided by the API.
-  $options += array(
-    'customized' => FALSE,
-    'not_customized' => FALSE,
-    'not_translated' => FALSE,
-  );
-  if (array_sum($options) == 0) {
-    // If user asked to not include anything in the translation files,
-    // that would not make sense, so just fall back on providing a template.
-    $language = NULL;
-  }
-
-  // Build and execute query to collect source strings and translations.
-  $query = db_select('locales_source', 's');
-  if (!empty($language)) {
-    if ($options['not_translated']) {
-      // Left join to keep untranslated strings in.
-      $query->leftJoin('locales_target', 't', 's.lid = t.lid AND t.language = :language', array(':language' => $language->langcode));
-    }
-    else {
-      // Inner join to filter for only translations.
-      $query->innerJoin('locales_target', 't', 's.lid = t.lid AND t.language = :language', array(':language' => $language->langcode));
-    }
-    if ($options['customized']) {
-      if (!$options['not_customized']) {
-        // Filter for customized strings only.
-        $query->condition('t.customized', LOCALE_CUSTOMIZED);
-      }
-      // Else no filtering needed in this case.
-    }
-    else {
-      if ($options['not_customized']) {
-        // Filter for non-customized strings only.
-        $query->condition('t.customized', LOCALE_NOT_CUSTOMIZED);
-      }
-      else {
-        // Filter for strings without translation.
-        $query->isNull('t.translation');
-      }
-    }
-    $query->fields('t', array('translation'));
-  }
-  else {
-    $query->leftJoin('locales_target', 't', 's.lid = t.lid');
-  }
-  $query->fields('s', array('lid', 'source', 'context', 'location'));
-  $result = $query->execute();
-
-  // Structure results in an array with metainformation on the strings.
-  $strings = array();
-  foreach ($result as $child) {
-    $strings[$child->lid] = array(
-      'comment'     => $child->location,
-      'source'      => $child->source,
-      'context'     => $child->context,
-      'translation' => isset($child->translation) ? $child->translation : '',
-    );
-  }
-  return $strings;
-}
-
-/**
- * Generates the PO(T) file contents for the given strings.
- *
- * @param $language
- *   Language object to generate the output for, or NULL if generating
- *   translation template.
- * @param $strings
- *   Array of strings to export. See _locale_export_get_strings()
- *   on how it should be formatted.
- * @param $header
- *   The header portion to use for the output file. Defaults
- *   are provided for PO and POT files.
- */
-function _locale_export_po_generate($language = NULL, $strings = array(), $header = NULL) {
-  global $user;
-
-  $locale_plurals = variable_get('locale_translation_plurals', array());
-
-  if (!isset($header)) {
-    if (isset($language)) {
-      $header = '# ' . $language->name . ' translation of ' . config('system.site')->get('name') . "\n";
-      $header .= '# Generated by ' . $user->name . ' <' . $user->mail . ">\n";
-      $header .= "#\n";
-      $header .= "msgid \"\"\n";
-      $header .= "msgstr \"\"\n";
-      $header .= "\"Project-Id-Version: PROJECT VERSION\\n\"\n";
-      $header .= "\"POT-Creation-Date: " . date("Y-m-d H:iO") . "\\n\"\n";
-      $header .= "\"PO-Revision-Date: " . date("Y-m-d H:iO") . "\\n\"\n";
-      $header .= "\"Last-Translator: NAME <EMAIL@ADDRESS>\\n\"\n";
-      $header .= "\"Language-Team: LANGUAGE <EMAIL@ADDRESS>\\n\"\n";
-      $header .= "\"MIME-Version: 1.0\\n\"\n";
-      $header .= "\"Content-Type: text/plain; charset=utf-8\\n\"\n";
-      $header .= "\"Content-Transfer-Encoding: 8bit\\n\"\n";
-      if (!empty($locale_plurals[$language->langcode]['formula'])) {
-        $header .= "\"Plural-Forms: nplurals=" . $locale_plurals[$language->langcode]['plurals'] . "; plural=" . strtr($locale_plurals[$language->langcode]['formula'], array('$' => '')) . ";\\n\"\n";
-        // Remember number of plural variants to optimize the export.
-        $nplurals = $locale_plurals[$language->langcode]['plurals'];
-      }
-      else {
-        // Remember we did not have a plural number for the export.
-        $nplurals = 0;
-      }
-    }
-    else {
-      $header = "# LANGUAGE translation of PROJECT\n";
-      $header .= "# Copyright (c) YEAR NAME <EMAIL@ADDRESS>\n";
-      $header .= "#\n";
-      $header .= "msgid \"\"\n";
-      $header .= "msgstr \"\"\n";
-      $header .= "\"Project-Id-Version: PROJECT VERSION\\n\"\n";
-      $header .= "\"POT-Creation-Date: " . date("Y-m-d H:iO") . "\\n\"\n";
-      $header .= "\"PO-Revision-Date: YYYY-mm-DD HH:MM+ZZZZ\\n\"\n";
-      $header .= "\"Last-Translator: NAME <EMAIL@ADDRESS>\\n\"\n";
-      $header .= "\"Language-Team: LANGUAGE <EMAIL@ADDRESS>\\n\"\n";
-      $header .= "\"MIME-Version: 1.0\\n\"\n";
-      $header .= "\"Content-Type: text/plain; charset=utf-8\\n\"\n";
-      $header .= "\"Content-Transfer-Encoding: 8bit\\n\"\n";
-      $header .= "\"Plural-Forms: nplurals=INTEGER; plural=EXPRESSION;\\n\"\n";
-    }
-  }
-
-  $output = $header . "\n";
-
-  foreach ($strings as $lid => $string) {
-    if ($string['comment']) {
-      $output .= '#: ' . $string['comment'] . "\n";
-    }
-    if (!empty($string['context'])) {
-      $output .= 'msgctxt ' . _locale_export_string($string['context']);
-    }
-    if (strpos($string['source'], LOCALE_PLURAL_DELIMITER) !== FALSE) {
-      // Export plural string.
-      $export_array = explode(LOCALE_PLURAL_DELIMITER, $string['source']);
-      $output .= 'msgid ' . _locale_export_string($export_array[0]);
-      $output .= 'msgid_plural ' . _locale_export_string($export_array[1]);
-      if (isset($language)) {
-        $export_array = explode(LOCALE_PLURAL_DELIMITER, $string['translation']);
-        for ($i = 0; $i < $nplurals; $i++) {
-          if (isset($export_array[$i])) {
-            $output .= 'msgstr[' . $i . '] ' . _locale_export_string($export_array[$i]);
-          }
-          else {
-            $output .= 'msgstr[' . $i . '] ""' . "\n";
-          }
-        }
-      }
-      else {
-        $output .= 'msgstr[0] ""' . "\n";
-        $output .= 'msgstr[1] ""' . "\n";
-      }
-    }
-    else {
-      $output .= 'msgid ' . _locale_export_string($string['source']);
-      $output .= 'msgstr ' . _locale_export_string($string['translation']);
-    }
-    $output .= "\n";
-  }
-  return $output;
-}
-
-/**
- * Writes a generated PO or POT file to the output.
- *
- * @param $language
- *   Language object to generate the output for, or NULL if generating
- *   translation template.
- * @param $output
- *   The PO(T) file to output as a string. See _locale_export_generate_po()
- *   on how it can be generated.
- */
-function _locale_export_po($language = NULL, $output = NULL) {
-  // Log the export event.
-  if (isset($language)) {
-    $filename = $language->langcode . '.po';
-    watchdog('locale', 'Exported %locale translation file: %filename.', array('%locale' => $language->name, '%filename' => $filename));
-  }
-  else {
-    $filename = 'drupal.pot';
-    watchdog('locale', 'Exported translation file: %filename.', array('%filename' => $filename));
-  }
-  // Download the file for the client.
-  header("Content-Disposition: attachment; filename=$filename");
-  header("Content-Type: text/plain; charset=utf-8");
-  print $output;
-  drupal_exit();
-}
-
-/**
- * Prints a string on multiple lines.
- */
-function _locale_export_string($str) {
-  $stri = addcslashes($str, "\0..\37\\\"");
-  $parts = array();
-
-  // Cut text into several lines
-  while ($stri != "") {
-    $i = strpos($stri, "\\n");
-    if ($i === FALSE) {
-      $curstr = $stri;
-      $stri = "";
-    }
-    else {
-      $curstr = substr($stri, 0, $i + 2);
-      $stri = substr($stri, $i + 2);
-    }
-    $curparts = explode("\n", _locale_export_wrap($curstr, 70));
-    $parts = array_merge($parts, $curparts);
-  }
-
-  // Multiline string
-  if (count($parts) > 1) {
-    return "\"\"\n\"" . implode("\"\n\"", $parts) . "\"\n";
-  }
-  // Single line string
-  elseif (count($parts) == 1) {
-    return "\"$parts[0]\"\n";
-  }
-  // No translation
-  else {
-    return "\"\"\n";
-  }
-}
-
-/**
- * Wraps text for Portable Object (Template) files.
- */
-function _locale_export_wrap($str, $len) {
-  $words = explode(' ', $str);
-  $return = array();
-
-  $cur = "";
-  $nstr = 1;
-  while (count($words)) {
-    $word = array_shift($words);
-    if ($nstr) {
-      $cur = $word;
-      $nstr = 0;
-    }
-    elseif (strlen("$cur $word") > $len) {
-      $return[] = $cur . " ";
-      $cur = $word;
-    }
-    else {
-      $cur = "$cur $word";
-    }
-  }
-  $return[] = $cur;
-
-  return implode("\n", $return);
-}
-
-/**
- * @} End of "defgroup locale-api-import-export".
- */
diff --git a/core/includes/install.inc b/core/includes/install.inc
index 1150fce103d4e5835e38f76eedfe8d6cfc551e08..d0a28bc188634dd5c361b374384965f9f8b9cb6c 100644
--- a/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -1,6 +1,7 @@
 <?php
 
 use Drupal\Core\Database\Database;
+use Drupal\locale\Gettext;
 
 /**
  * Indicates that a module has not been installed yet.
@@ -700,13 +701,7 @@ function st($string, array $args = array(), array $options = array()) {
       // that multiple files end with the same extension, even if unlikely.
       $files = install_find_translation_files($install_state['parameters']['langcode']);
       if (!empty($files)) {
-        // Include cross-dependent code from locale module and gettext.inc.
-        require_once DRUPAL_ROOT . '/core/modules/locale/locale.module';
-        require_once DRUPAL_ROOT . '/core/includes/gettext.inc';
-        foreach ($files as $file) {
-          _locale_import_read_po('mem-store', $file);
-        }
-        $strings = _locale_import_one_string('mem-report');
+        $strings = Gettext::filesToArray($install_state['parameters']['langcode'], $files);
       }
     }
   }
diff --git a/core/lib/Drupal/Component/Gettext/PoHeader.php b/core/lib/Drupal/Component/Gettext/PoHeader.php
new file mode 100644
index 0000000000000000000000000000000000000000..ae68abcd8046861f18c414121c908626f754a4d5
--- /dev/null
+++ b/core/lib/Drupal/Component/Gettext/PoHeader.php
@@ -0,0 +1,418 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Component\Gettext\PoHeader
+ */
+
+namespace Drupal\Component\Gettext;
+
+/**
+ * Gettext PO header handler.
+ *
+ * Possible Gettext PO header elements are explained in
+ * http://www.gnu.org/software/gettext/manual/gettext.html#Header-Entry,
+ * but we only support a subset of these directly.
+ *
+ * Example header:
+ *
+ * "Project-Id-Version: Drupal core (7.11)\n"
+ * "POT-Creation-Date: 2012-02-12 22:59+0000\n"
+ * "PO-Revision-Date: YYYY-mm-DD HH:MM+ZZZZ\n"
+ * "Language-Team: Catalan\n"
+ * "MIME-Version: 1.0\n"
+ * "Content-Type: text/plain; charset=utf-8\n"
+ * "Content-Transfer-Encoding: 8bit\n"
+ * "Plural-Forms: nplurals=2; plural=(n>1);\n"
+ */
+class PoHeader {
+
+  /**
+   * Language code.
+   *
+   * @var string
+   */
+  private $_langcode;
+
+  /**
+   * Formula for the plural form.
+   *
+   * @var string
+   */
+  private $_pluralForms;
+
+  /**
+   * Author(s) of the file.
+   *
+   * @var string
+   */
+  private $_authors;
+
+  /**
+   * Date the po file got created.
+   *
+   * @var string
+   */
+  private $_po_date;
+
+  /**
+   * Human readable language name.
+   *
+   * @var string
+   */
+  private $_languageName;
+
+  /**
+   * Name of the project the translation belongs to.
+   *
+   * @var string
+   */
+  private $_projectName;
+
+  /**
+   * Constructor, creates a PoHeader with default values.
+   *
+   * @param string $langcode
+   *   Language code.
+   */
+  public function __construct($langcode = NULL) {
+    $this->_langcode = $langcode;
+    $this->_po_date = date("Y-m-d H:iO");
+    $this->_pluralForms = 'nplurals=2; plural=(n > 1);';
+  }
+
+  /**
+   * Get the plural form.
+   *
+   * @return string
+   *   Plural form component from the header, for example:
+   *   'nplurals=2; plural=(n > 1);'.
+   */
+  function getPluralForms() {
+    return $this->_pluralForms;
+  }
+
+  /**
+   * Set the human readable language name.
+   *
+   * @param string $languageName
+   *   Human readable language name.
+   */
+  function setLanguageName($languageName) {
+    $this->_languageName = $languageName;
+  }
+
+  /**
+   * Get the human readable language name.
+   *
+   * @return string
+   *   The human readable language name.
+   */
+  function getLanguageName() {
+    return $this->_languageName;
+  }
+
+  /**
+   * Set the project name.
+   *
+   * @param string $projectName
+   *   Human readable project name.
+   */
+  function setProjectName($projectName) {
+    $this->_projectName = $projectName;
+  }
+
+  /**
+   * Get the project name.
+   *
+   * @return string
+   *   The human readable project name.
+   */
+  function getProjectName() {
+    return $this->_projectName;
+  }
+
+  /**
+   * Populate internal values from a string.
+   *
+   * @param string $header
+   *   Full header string with key-value pairs.
+   */
+  public function setFromString($header) {
+    // Get an array of all header values for processing.
+    $values = $this->parseHeader($header);
+
+    // There is only one value relevant for our header implementation when
+    // reading, and that is the plural formula.
+    if (!empty($values['Plural-Forms'])) {
+      $this->_pluralForms = $values['Plural-Forms'];
+    }
+  }
+
+  /**
+   * Generate a Gettext PO formatted header string based on data set earlier.
+   */
+  public function __toString() {
+    $output = '';
+
+    $isTemplate = empty($this->_languageName);
+
+    $output .= '# ' . ($isTemplate ? 'LANGUAGE' : $this->_languageName) . ' translation of ' . ($isTemplate ? 'PROJECT' : $this->_projectName) . "\n";
+    if (!empty($this->_authors)) {
+      $output .= '# Generated by ' . implode("\n# ", $this->_authors) . "\n";
+    }
+    $output .= "#\n";
+
+    // Add the actual header information.
+    $output .= "msgid \"\"\n";
+    $output .= "msgstr \"\"\n";
+    $output .= "\"Project-Id-Version: PROJECT VERSION\\n\"\n";
+    $output .= "\"POT-Creation-Date: " . $this->_po_date . "\\n\"\n";
+    $output .= "\"PO-Revision-Date: " . $this->_po_date . "\\n\"\n";
+    $output .= "\"Last-Translator: NAME <EMAIL@ADDRESS>\\n\"\n";
+    $output .= "\"Language-Team: LANGUAGE <EMAIL@ADDRESS>\\n\"\n";
+    $output .= "\"MIME-Version: 1.0\\n\"\n";
+    $output .= "\"Content-Type: text/plain; charset=utf-8\\n\"\n";
+    $output .= "\"Content-Transfer-Encoding: 8bit\\n\"\n";
+    $output .= "\"Plural-Forms: " . $this->_pluralForms . "\\n\"\n";
+    $output .= "\n";
+
+    return $output;
+  }
+
+  /**
+   * Parses a Plural-Forms entry from a Gettext Portable Object file header.
+   *
+   * @param string $pluralforms
+   *   The Plural-Forms entry value.
+   *
+   * @return
+   *   An array containing the number of plural forms and the converted version
+   *   of the formula that can be evaluated with PHP later.
+   */
+  function parsePluralForms($pluralforms) {
+    // First, delete all whitespace.
+    $pluralforms = strtr($pluralforms, array(" " => "", "\t" => ""));
+
+    // Select the parts that define nplurals and plural.
+    $nplurals = strstr($pluralforms, "nplurals=");
+    if (strpos($nplurals, ";")) {
+      // We want the string from the 10th char, because "nplurals=" length is 9.
+      $nplurals = substr($nplurals, 9, strpos($nplurals, ";") - 9);
+    }
+    else {
+      return FALSE;
+    }
+    $plural = strstr($pluralforms, "plural=");
+    if (strpos($plural, ";")) {
+      // We want the string from the 8th char, because "plural=" length is 7.
+      $plural = substr($plural, 7, strpos($plural, ";") - 7);
+    }
+    else {
+      return FALSE;
+    }
+
+    // Get PHP version of the plural formula.
+    $plural = $this->parseArithmetic($plural);
+
+    if ($plural !== FALSE) {
+      return array($nplurals, $plural);
+    }
+    else {
+      throw new Exception('The plural formula could not be parsed.');
+    }
+  }
+
+  /**
+   * Parses a Gettext Portable Object file header.
+   *
+   * @param string $header
+   *   A string containing the complete header.
+   *
+   * @return array
+   *   An associative array of key-value pairs.
+   */
+  private function parseHeader($header) {
+    $header_parsed = array();
+    $lines = array_map('trim', explode("\n", $header));
+    foreach ($lines as $line) {
+      if ($line) {
+        list($tag, $contents) = explode(":", $line, 2);
+        $header_parsed[trim($tag)] = trim($contents);
+      }
+    }
+    return $header_parsed;
+  }
+
+  /**
+   * Parses and sanitizes an arithmetic formula into a PHP expression.
+   *
+   * While parsing, we ensure, that the operators have the right
+   * precedence and associativity.
+   *
+   * @param string $string
+   *   A string containing the arithmetic formula.
+   *
+   * @return
+   *   A version of the formula to evaluate with PHP later.
+   */
+  private function parseArithmetic($string) {
+    // Operator precedence table.
+    $precedence = array("(" => -1, ")" => -1, "?" => 1, ":" => 1, "||" => 3, "&&" => 4, "==" => 5, "!=" => 5, "<" => 6, ">" => 6, "<=" => 6, ">=" => 6, "+" => 7, "-" => 7, "*" => 8, "/" => 8, "%" => 8);
+    // Right associativity.
+    $right_associativity = array("?" => 1, ":" => 1);
+
+    $tokens = $this->tokenizeFormula($string);
+
+    // Parse by converting into infix notation then back into postfix
+    // Operator stack - holds math operators and symbols.
+    $operator_stack = array();
+    // Element Stack - holds data to be operated on.
+    $element_stack = array();
+
+    foreach ($tokens as $token) {
+      $current_token = $token;
+
+      // Numbers and the $n variable are simply pushed into $element_stack.
+      if (is_numeric($token)) {
+        $element_stack[] = $current_token;
+      }
+      elseif ($current_token == "n") {
+        $element_stack[] = '$n';
+      }
+      elseif ($current_token == "(") {
+        $operator_stack[] = $current_token;
+      }
+      elseif ($current_token == ")") {
+        $topop = array_pop($operator_stack);
+        while (isset($topop) && ($topop != "(")) {
+          $element_stack[] = $topop;
+          $topop = array_pop($operator_stack);
+        }
+      }
+      elseif (!empty($precedence[$current_token])) {
+        // If it's an operator, then pop from $operator_stack into
+        // $element_stack until the precedence in $operator_stack is less
+        // than current, then push into $operator_stack.
+        $topop = array_pop($operator_stack);
+        while (isset($topop) && ($precedence[$topop] >= $precedence[$current_token]) && !(($precedence[$topop] == $precedence[$current_token]) && !empty($right_associativity[$topop]) && !empty($right_associativity[$current_token]))) {
+          $element_stack[] = $topop;
+          $topop = array_pop($operator_stack);
+        }
+        if ($topop) {
+          // Return element to top.
+          $operator_stack[] = $topop;
+        }
+        // Parentheses are not needed.
+        $operator_stack[] = $current_token;
+      }
+      else {
+        return FALSE;
+      }
+    }
+
+    // Flush operator stack.
+    $topop = array_pop($operator_stack);
+    while ($topop != NULL) {
+      $element_stack[] = $topop;
+      $topop = array_pop($operator_stack);
+    }
+
+    // Now extract formula from stack.
+    $previous_size = count($element_stack) + 1;
+    while (count($element_stack) < $previous_size) {
+      $previous_size = count($element_stack);
+      for ($i = 2; $i < count($element_stack); $i++) {
+        $op = $element_stack[$i];
+        if (!empty($precedence[$op])) {
+          $f = "";
+          if ($op == ":") {
+            $f = $element_stack[$i - 2] . "):" . $element_stack[$i - 1] . ")";
+          }
+          elseif ($op == "?") {
+            $f = "(" . $element_stack[$i - 2] . "?(" . $element_stack[$i - 1];
+          }
+          else {
+            $f = "(" . $element_stack[$i - 2] . $op . $element_stack[$i - 1] . ")";
+          }
+          array_splice($element_stack, $i - 2, 3, $f);
+          break;
+        }
+      }
+    }
+
+    // If only one element is left, the number of operators is appropriate.
+    if (count($element_stack) == 1) {
+      return $element_stack[0];
+    }
+    else {
+      return FALSE;
+    }
+  }
+
+  /**
+   * Tokenize the formula.
+   *
+   * @param string $formula
+   *   A string containing the arithmetic formula.
+   *
+   * @return array
+   *   List of arithmetic tokens identified in the formula.
+   */
+  private function tokenizeFormula($formula) {
+    $formula = str_replace(" ", "", $formula);
+    $tokens = array();
+    for ($i = 0; $i < strlen($formula); $i++) {
+      if (is_numeric($formula[$i])) {
+        $num = $formula[$i];
+        $j = $i + 1;
+        while ($j < strlen($formula) && is_numeric($formula[$j])) {
+          $num .= $formula[$j];
+          $j++;
+        }
+        $i = $j - 1;
+        $tokens[] = $num;
+      }
+      elseif ($pos = strpos(" =<>!&|", $formula[$i])) {
+        $next = $formula[$i + 1];
+        switch ($pos) {
+          case 1:
+          case 2:
+          case 3:
+          case 4:
+            if ($next == '=') {
+              $tokens[] = $formula[$i] . '=';
+              $i++;
+            }
+            else {
+              $tokens[] = $formula[$i];
+            }
+            break;
+          case 5:
+            if ($next == '&') {
+              $tokens[] = '&&';
+              $i++;
+            }
+            else {
+              $tokens[] = $formula[$i];
+            }
+            break;
+          case 6:
+            if ($next == '|') {
+              $tokens[] = '||';
+              $i++;
+            }
+            else {
+              $tokens[] = $formula[$i];
+            }
+            break;
+        }
+      }
+      else {
+        $tokens[] = $formula[$i];
+      }
+    }
+    return $tokens;
+  }
+
+}
diff --git a/core/lib/Drupal/Component/Gettext/PoItem.php b/core/lib/Drupal/Component/Gettext/PoItem.php
new file mode 100644
index 0000000000000000000000000000000000000000..599a58a5a5a1ae134cefbbc749997ae8c0305d4d
--- /dev/null
+++ b/core/lib/Drupal/Component/Gettext/PoItem.php
@@ -0,0 +1,287 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Component\Gettext\PoItem.
+ */
+
+namespace Drupal\Component\Gettext;
+
+/**
+ * PoItem handles one translation.
+ *
+ * @todo: This class contains some really old legacy code.
+ * @see https://drupal.org/node/1637662
+ */
+class PoItem {
+
+  /**
+   * The language code this translation is in.
+   *
+   * @car string
+   */
+  private $_langcode;
+
+  /**
+   * The context this translation belongs to.
+   *
+   * @var string
+   */
+  private $_context = '';
+
+  /**
+   * The source string or array of strings if it has plurals.
+   *
+   * @var string or array
+   * @see $_plural
+   */
+  private $_source;
+
+  /**
+   * Flag indicating if this translation has plurals.
+   *
+   * @var boolean
+   */
+  private $_plural;
+
+  /**
+   * The comment of this translation.
+   *
+   * @var string
+   */
+  private $_comment;
+
+  /**
+   * The translation string or array of strings if it has plurals.
+   *
+   * @var string or array
+   * @see $_plural
+   */
+  private $_translation;
+
+  /**
+   * Get the language code of the currently used language.
+   *
+   * @return string with langcode
+   */
+  function getLangcode() {
+    return $this->_langcode;
+  }
+
+  /**
+   * Set the language code of the current language.
+   *
+   * @param string $langcode
+   */
+  function setLangcode($langcode) {
+    $this->_langcode = $langcode;
+  }
+
+  /**
+   * Get the context this translation belongs to.
+   *
+   * @return string $context
+   */
+  function getContext() {
+    return $this->_context;
+  }
+
+  /**
+   * Set the context this translation belongs to.
+   *
+   * @param string $context
+   */
+  function setContext($context) {
+    $this->_context = $context;
+  }
+
+  /**
+   * Get the source string or the array of strings if the translation has
+   * plurals.
+   *
+   * @return string or array $translation
+   */
+  function getSource() {
+    return $this->_source;
+  }
+
+  /**
+   * Set the source string or the array of strings if the translation has
+   * plurals.
+   *
+   * @param string or array $source
+   */
+  function setSource($source) {
+    $this->_source = $source;
+  }
+
+  /**
+   * Get the translation string or the array of strings if the translation has
+   * plurals.
+   *
+   * @return string or array $translation
+   */
+  function getTranslation() {
+    return $this->_translation;
+  }
+
+  /**
+   * Set the translation string or the array of strings if the translation has
+   * plurals.
+   *
+   * @param string or array $translation
+   */
+  function setTranslation($translation) {
+    $this->_translation = $translation;
+  }
+
+  /**
+   * Set if the translation has plural values.
+   *
+   * @param boolean $plural
+   */
+  function setPlural($plural) {
+    $this->_plural = $plural;
+  }
+
+  /**
+   * Get if the translation has plural values.
+   *
+   * @return boolean $plural
+   */
+  function isPlural() {
+    return $this->_plural;
+  }
+
+  /**
+   * Get the comment of this translation.
+   *
+   * @return String $comment
+   */
+  function getComment() {
+    return $this->_comment;
+  }
+
+  /**
+   * Set the comment of this translation.
+   *
+   * @param String $comment
+   */
+  function setComment($comment) {
+    $this->_comment = $comment;
+  }
+
+  /**
+   * Create the PoItem from a structured array.
+   *
+   * @param array values
+   */
+  public function setFromArray(array $values = array()) {
+    if (isset($values['context'])) {
+      $this->setContext($values['context']);
+    }
+    if (isset($values['source'])) {
+      $this->setSource($values['source']);
+    }
+    if (isset($values['translation'])) {
+      $this->setTranslation($values['translation']);
+    }
+    if (isset($values['comment'])){
+      $this->setComment($values['comment']);
+    }
+    if (isset($this->_source) &&
+        strpos($this->_source, LOCALE_PLURAL_DELIMITER) !== FALSE) {
+      $this->setSource(explode(LOCALE_PLURAL_DELIMITER, $this->_source));
+      $this->setTranslation(explode(LOCALE_PLURAL_DELIMITER, $this->_translation));
+      $this->setPlural(count($this->_translation) > 1);
+    }
+  }
+
+  /**
+   * Output the PoItem as a string.
+   */
+  public function __toString() {
+    return $this->formatItem();
+  }
+
+  /**
+   * Format the POItem as a string.
+   */
+  private function formatItem() {
+    $output = '';
+
+    // Format string context.
+    if (!empty($this->_context)) {
+      $output .= 'msgctxt ' . $this->formatString($this->_context);
+    }
+
+    // Format translation.
+    if ($this->_plural) {
+      $output .= $this->formatPlural();
+    }
+    else {
+      $output .= $this->formatSingular();
+    }
+
+    // Add one empty line to separate the translations.
+    $output .= "\n";
+
+    return $output;
+  }
+
+  /**
+   * Formats a plural translation.
+   */
+  private function formatPlural() {
+    $output = '';
+
+    // Format source strings.
+    $output .= 'msgid ' . $this->formatString($this->_source[0]);
+    $output .= 'msgid_plural ' . $this->formatString($this->_source[1]);
+
+    foreach ($this->_translation as $i => $trans) {
+      if (isset($this->_translation[$i])) {
+        $output .= 'msgstr[' . $i . '] ' . $this->formatString($trans);
+      }
+      else {
+        $output .= 'msgstr[' . $i . '] ""' . "\n";
+      }
+    }
+
+    return $output;
+  }
+
+  /**
+   * Formats a singular translation.
+   */
+  private function formatSingular() {
+    $output = '';
+    $output .= 'msgid '. $this->formatString($this->_source);
+    $output .= 'msgstr '. (isset($this->_translation) ? $this->formatString($this->_translation) : '');
+    return $output;
+  }
+
+  /**
+   * Formats a string for output on multiple lines.
+   */
+  private function formatString($string) {
+    // Escape characters for processing.
+    $string = addcslashes($string, "\0..\37\\\"");
+
+    // Always include a line break after the explicit \n line breaks from
+    // the source string. Otherwise wrap at 70 chars to accommodate the extra
+    // format overhead too.
+    $parts = explode("\n", wordwrap(str_replace('\n', "\\n\n", $string), 70, " \n"));
+
+    // Multiline string should be exported starting with a "" and newline to
+    // have all lines aligned on the same column.
+    if (count($parts) > 1) {
+      return "\"\"\n\"" . implode("\"\n\"", $parts) . "\"\n";
+    }
+    // Single line strings are output on the same line.
+    else {
+      return "\"$parts[0]\"\n";
+    }
+  }
+
+}
diff --git a/core/lib/Drupal/Component/Gettext/PoMemoryWriter.php b/core/lib/Drupal/Component/Gettext/PoMemoryWriter.php
new file mode 100644
index 0000000000000000000000000000000000000000..e304451314bd150e866734d492c20418d63ce4d0
--- /dev/null
+++ b/core/lib/Drupal/Component/Gettext/PoMemoryWriter.php
@@ -0,0 +1,95 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Component\Gettext\PoMemoryWriter.
+ */
+
+namespace Drupal\Component\Gettext;
+
+use Drupal\Component\Gettext\PoWriterInterface;
+use Drupal\Component\Gettext\PoHeader;
+use Drupal\Component\Gettext\PoItem;
+
+/**
+ * Defines a Gettext PO memory writer, to be used by the installer.
+ */
+class PoMemoryWriter implements PoWriterInterface {
+
+  /**
+   * Array to hold all PoItem elements.
+   *
+   * @var array
+   */
+  private $_items;
+
+  /**
+   * Constructor, initialize empty items.
+   */
+  function __construct() {
+    $this->_items = array();
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoWriterInterface::writeItem().
+   */
+  public function writeItem(PoItem $item) {
+    if (is_array($item->source)) {
+      $item->source = implode(LOCALE_PLURAL_DELIMITER, $item->source);
+      $item->translation = implode(LOCALE_PLURAL_DELIMITER, $item->translation);
+    }
+    $this->_items[isset($item->context) ? $item->context : ''][$item->source] = $item->translation;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoWriterInterface::writeItems().
+   */
+  public function writeItems(PoReaderInterface $reader, $count = -1) {
+    $forever = $count == -1;
+    while (($count-- > 0 || $forever) && ($item = $reader->readItem())) {
+      $this->writeItem($item);
+    }
+  }
+
+  /**
+   * Get all stored PoItem's.
+   *
+   * @return array PoItem
+   */
+  public function getData() {
+    return $this->_items;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface:setLangcode().
+   *
+   * Not implemented. Not relevant for the MemoryWriter.
+   */
+  function setLangcode($langcode) {
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface:getLangcode().
+   *
+   * Not implemented. Not relevant for the MemoryWriter.
+   */
+  function getLangcode() {
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface:getHeader().
+   *
+   * Not implemented. Not relevant for the MemoryWriter.
+   */
+  function getHeader() {
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface:setHeader().
+   *
+   * Not implemented. Not relevant for the MemoryWriter.
+   */
+  function setHeader(PoHeader $header) {
+  }
+
+}
diff --git a/core/lib/Drupal/Component/Gettext/PoMetadataInterface.php b/core/lib/Drupal/Component/Gettext/PoMetadataInterface.php
new file mode 100644
index 0000000000000000000000000000000000000000..f5bb3db0c75e13c40d0c44c9d3b187da432627e8
--- /dev/null
+++ b/core/lib/Drupal/Component/Gettext/PoMetadataInterface.php
@@ -0,0 +1,51 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Component\Gettext\PoMetadataInterface.
+ */
+
+namespace Drupal\Component\Gettext;
+
+use Drupal\Component\Gettext\PoHeader;
+
+/**
+ * Methods required for both reader and writer implementations.
+ *
+ * @see Drupal\Component\Gettext\PoReaderInterface
+ * @see Drupal\Component\Gettext\PoWriterInterface
+ */
+interface PoMetadataInterface {
+
+  /**
+   * Set language code.
+   *
+   * @param string $langcode
+   *   Language code string.
+   */
+  function setLangcode($langcode);
+
+  /**
+   * Get language code.
+   *
+   * @return string
+   *   Language code string.
+   */
+  function getLangcode();
+
+  /**
+   * Set header metadata.
+   *
+   * @param Drupal\Component\Gettext\PoHeader $header
+   *   Header object representing metadata in a PO header.
+   */
+  function setHeader(PoHeader $header);
+
+  /**
+   * Get header metadata.
+   *
+   * @return Drupal\Component\Gettext\PoHeader $header
+   *   Header instance representing metadata in a PO header.
+   */
+  function getHeader();
+}
diff --git a/core/lib/Drupal/Component/Gettext/PoReaderInterface.php b/core/lib/Drupal/Component/Gettext/PoReaderInterface.php
new file mode 100644
index 0000000000000000000000000000000000000000..e9c01254d80c11d278b03d4089fd316e5f04fec8
--- /dev/null
+++ b/core/lib/Drupal/Component/Gettext/PoReaderInterface.php
@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Component\Gettext\PoReaderInterface.
+ */
+
+namespace Drupal\Component\Gettext;
+
+use Drupal\Component\Gettext\PoMetadataInterface;
+
+/**
+ * Shared interface definition for all Gettext PO Readers.
+ */
+interface PoReaderInterface extends PoMetadataInterface {
+
+  /**
+   * Reads and returns a PoItem (source/translation pair).
+   *
+   * @return Drupal\Component\Gettext\PoItem
+   *   Wrapper for item data instance.
+   */
+  function readItem();
+}
diff --git a/core/lib/Drupal/Component/Gettext/PoStreamInterface.php b/core/lib/Drupal/Component/Gettext/PoStreamInterface.php
new file mode 100644
index 0000000000000000000000000000000000000000..c9f9e347ee8780b0d014c2282ddbb55d52390f22
--- /dev/null
+++ b/core/lib/Drupal/Component/Gettext/PoStreamInterface.php
@@ -0,0 +1,43 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Component\Gettext\PoStreamInterface.
+ */
+
+namespace Drupal\Component\Gettext;
+
+/**
+ * Common functions for file/stream based PO readers/writers.
+ *
+ * @see PoReaderInterface
+ * @see PoWriterInterface
+ */
+interface PoStreamInterface {
+
+  /**
+   * Open the stream. Set the URI for the stream earlier with setURI().
+   */
+  function open();
+
+  /**
+   * Close the stream.
+   */
+  function close();
+
+  /**
+   * Get the URI of the PO stream that is being read or written.
+   *
+   * @return
+   *   URI string for this stream.
+   */
+  function getURI();
+
+  /**
+   * Set the URI of the PO stream that is going to be read or written.
+   *
+   * @param $uri
+   *   URI string to set for this stream.
+   */
+  function setURI($uri);
+}
diff --git a/core/lib/Drupal/Component/Gettext/PoStreamReader.php b/core/lib/Drupal/Component/Gettext/PoStreamReader.php
new file mode 100644
index 0000000000000000000000000000000000000000..bd916a7e30d97026585f0fc3718348c67f4131cb
--- /dev/null
+++ b/core/lib/Drupal/Component/Gettext/PoStreamReader.php
@@ -0,0 +1,589 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Component\Gettext\PoStreamReader.
+ */
+
+namespace Drupal\Component\Gettext;
+
+use Drupal\Component\Gettext\PoReaderInterface;
+use Drupal\Component\Gettext\PoStreamInterface;
+use Drupal\Component\Gettext\PoHeader;
+
+/**
+ * Implements Gettext PO stream reader.
+ *
+ * The PO file format parsing is implemented according to the documentation at
+ * http://www.gnu.org/software/gettext/manual/gettext.html#PO-Files
+ */
+class PoStreamReader implements PoStreamInterface, PoReaderInterface {
+
+  /**
+   * Source line number of the stream being parsed.
+   *
+   * @var int
+   */
+  private $_line_number = 0;
+
+  /**
+   * Parser context for the stream reader state machine.
+   *
+   * Possible contexts are:
+   *  - 'COMMENT' (#)
+   *  - 'MSGID' (msgid)
+   *  - 'MSGID_PLURAL' (msgid_plural)
+   *  - 'MSGCTXT' (msgctxt)
+   *  - 'MSGSTR' (msgstr or msgstr[])
+   *  - 'MSGSTR_ARR' (msgstr_arg)
+   *
+   * @var string
+   */
+  private $_context = 'COMMENT';
+
+  /**
+   * Current entry being read. Incomplete.
+   *
+   * @var array
+   */
+  private $_current_item = array();
+
+  /**
+   * Current plural index for plural translations.
+   *
+   * @var int
+   */
+  private $_current_plural_index = 0;
+
+  /**
+   * URI of the PO stream that is being read.
+   *
+   * @var string
+   */
+  private $_uri = '';
+
+  /**
+   * Language code for the PO stream being read.
+   *
+   * @var string
+   */
+  private $_langcode = NULL;
+
+  /**
+   * Size of the current PO stream.
+   *
+   * @var int
+   */
+  private $_size;
+
+  /**
+   * File handle of the current PO stream.
+   *
+   * @var resource
+   */
+  private $_fd;
+
+  /**
+   * The PO stream header.
+   *
+   * @var Drupal\Component\Gettext\PoHeader
+   */
+  private $_header;
+
+  /**
+   * Object wrapper for the last read source/translation pair.
+   *
+   * @var Drupal\Component\Gettext\PoItem
+   */
+  private $_last_item;
+
+  /**
+   * Indicator of whether the stream reading is finished.
+   *
+   * @var boolean
+   */
+  private $_finished;
+
+  /**
+   * Array of translated error strings recorded on reading this stream so far.
+   *
+   * @var array
+   */
+  private $_errors;
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::getLangcode().
+   */
+  public function getLangcode() {
+    return $this->_langcode;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::setLangcode().
+   */
+  public function setLangcode($langcode) {
+    $this->_langcode = $langcode;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::getHeader().
+   */
+  public function getHeader() {
+    return $this->_header;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::setHeader().
+   *
+   * Not applicable to stream reading and therefore not implemented.
+   */
+  public function setHeader(PoHeader $header) {
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoStreamInterface::getURI().
+   */
+  public function getURI() {
+    return $this->_uri;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoStreamInterface::setURI().
+   */
+  public function setURI($uri) {
+    $this->_uri = $uri;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoStreamInterface::open().
+   *
+   * Opens the stream and reads the header. The stream is ready for reading
+   * items after.
+   *
+   * @throws Exception
+   *   If the URI is not yet set.
+   */
+  public function open() {
+    if (!empty($this->_uri)) {
+      $this->_fd = fopen($this->_uri, 'rb');
+      $this->_size = ftell($this->_fd);
+      $this->readHeader();
+    }
+    else {
+      throw new Exception('Cannot open stream without URI set.');
+    }
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoStreamInterface::close().
+   *
+   * @throws Exception
+   *   If the stream is not open.
+   */
+  public function close() {
+    if ($this->_fd) {
+      fclose($this->_fd);
+    }
+    else {
+      throw new Exception('Cannot close stream that is not open.');
+    }
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoReaderInterface::readItem().
+   */
+  public function readItem() {
+    // Clear out the last item.
+    $this->_last_item = NULL;
+
+    // Read until finished with the stream or a complete item was identified.
+    while (!$this->_finished && is_null($this->_last_item)) {
+      $this->readLine();
+    }
+
+    return $this->_last_item;
+  }
+
+  /**
+   * Read the header from the PO stream.
+   *
+   * The header is a special case PoItem, using the empty string as source and
+   * key-value pairs as translation. We just reuse the item reader logic to
+   * read the header.
+   */
+  private function readHeader() {
+    $item = $this->readItem();
+    $header = new PoHeader;
+    $header->setFromString(trim($item->getTranslation()));
+    $this->_header = $header;
+  }
+
+  /**
+   * Reads a line from the PO stream and stores data internally.
+   *
+   * Expands $this->_current_item based on new data for the current item. If
+   * this line ends the current item, it is saved with setItemFromArray() with
+   * data from $this->_current_item.
+   *
+   * An internal state machine is maintained in this reader using $this->_context
+   * as the reading state. PO items are inbetween COMMENT states (when items have
+   * at least one line or comment inbetween them or indicated by MSGSTR or
+   * MSGSTR_ARR followed immediately by an MSGID or MSGCTXT (when items closely
+   * follow each other).
+   *
+   * @return
+   *   FALSE if an error was logged, NULL otherwise. The errors are considered
+   *   non-blocking, so reading can continue, while the errors are collected
+   *   for later presentation.
+   */
+  private function readLine() {
+    // Read a line and set the stream finished indicator if it was not
+    // possible anymore.
+    $line = fgets($this->_fd);
+    $this->_finished = ($line === FALSE);
+
+    if (!$this->_finished) {
+
+      if ($this->_line_number == 0) {
+        // The first line might come with a UTF-8 BOM, which should be removed.
+        $line = str_replace("\xEF\xBB\xBF", '', $line);
+        // Current plurality for 'msgstr[]'.
+        $this->_current_plural_index = 0;
+      }
+
+      // Track the line number for error reporting.
+      $this->_line_number++;
+
+      // Initialize common values for error logging.
+      $log_vars = array(
+        '%uri' => $this->getURI(),
+        '%line' => $this->_line_number,
+      );
+      $t = get_t();
+
+      // Trim away the linefeed. \\n might appear at the end of the string if
+      // another line continuing the same string follows. We can remove that.
+      $line = trim(strtr($line, array("\\\n" => "")));
+
+      if (!strncmp('#', $line, 1)) {
+        // Lines starting with '#' are comments.
+
+        if ($this->_context == 'COMMENT') {
+          // Already in comment context, add to current comment.
+          $this->_current_item['#'][] = substr($line, 1);
+        }
+        elseif (($this->_context == 'MSGSTR') || ($this->_context == 'MSGSTR_ARR')) {
+          // We are currently in string context, save current item.
+          $this->setItemFromArray($this->_current_item);
+
+          // Start a new entry for the comment.
+          $this->_current_item = array();
+          $this->_current_item['#'][] = substr($line, 1);
+
+          $this->_context = 'COMMENT';
+          return;
+        }
+        else {
+          // A comment following any other context is a syntax error.
+          $this->_errors[] = $t('The translation stream %uri contains an error: "msgstr" was expected but not found on line %line.', $log_vars);
+          return FALSE;
+        }
+        return;
+      }
+      elseif (!strncmp('msgid_plural', $line, 12)) {
+        // A plural form for the current source string.
+
+        if ($this->_context != 'MSGID') {
+          // A plural form can only be added to an msgid directly.
+          $this->_errors[] = $t('The translation stream %uri contains an error: "msgid_plural" was expected but not found on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        // Remove 'msgid_plural' and trim away whitespace.
+        $line = trim(substr($line, 12));
+
+        // Only the plural source string is left, parse it.
+        $quoted = $this->parseQuoted($line);
+        if ($quoted === FALSE) {
+          // The plural form must be wrapped in quotes.
+          $this->_errors[] = $t('The translation stream %uri contains a syntax error on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        // Append the plural source to the current entry.
+        if (is_string($this->_current_item['msgid'])) {
+          // The first value was stored as string. Now we know the context is
+          // plural, it is converted to array.
+          $this->_current_item['msgid'] = array($this->_current_item['msgid']);
+        }
+        $this->_current_item['msgid'][] = $quoted;
+
+        $this->_context = 'MSGID_PLURAL';
+        return;
+      }
+      elseif (!strncmp('msgid', $line, 5)) {
+        // Starting a new message.
+
+        if (($this->_context == 'MSGSTR') || ($this->_context == 'MSGSTR_ARR')) {
+          // We are currently in string context, save current item.
+          $this->setItemFromArray($this->_current_item);
+
+          // Start a new context for the msgid.
+          $this->_current_item = array();
+        }
+        elseif ($this->_context == 'MSGID') {
+          // We are currently already in the context, meaning we passed an id with no data.
+          $this->_errors[] = $t('The translation stream %uri contains an error: "msgid" is unexpected on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        // Remove 'msgid' and trim away whitespace.
+        $line = trim(substr($line, 5));
+
+        // Only the message id string is left, parse it.
+        $quoted = $this->parseQuoted($line);
+        if ($quoted === FALSE) {
+          // The message id must be wrapped in quotes.
+          $this->_errors[] = $t('The translation stream %uri contains an error: invalid format for "msgid" on line %line.', $log_vars, $log_vars);
+          return FALSE;
+        }
+
+        $this->_current_item['msgid'] = $quoted;
+        $this->_context = 'MSGID';
+        return;
+      }
+      elseif (!strncmp('msgctxt', $line, 7)) {
+        // Starting a new context.
+
+        if (($this->_context == 'MSGSTR') || ($this->_context == 'MSGSTR_ARR')) {
+          // We are currently in string context, save current item.
+          $this->setItemFromArray($this->_current_item);
+          $this->_current_item = array();
+        }
+        elseif (!empty($this->_current_item['msgctxt'])) {
+          // A context cannot apply to another context.
+          $this->_errors[] = $t('The translation stream %uri contains an error: "msgctxt" is unexpected on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        // Remove 'msgctxt' and trim away whitespaces.
+        $line = trim(substr($line, 7));
+
+        // Only the msgctxt string is left, parse it.
+        $quoted = $this->parseQuoted($line);
+        if ($quoted === FALSE) {
+          // The context string must be quoted.
+          $this->_errors[] = $t('The translation stream %uri contains an error: invalid format for "msgctxt" on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        $this->_current_item['msgctxt'] = $quoted;
+
+        $this->_context = 'MSGCTXT';
+        return;
+      }
+      elseif (!strncmp('msgstr[', $line, 7)) {
+        // A message string for a specific plurality.
+
+        if (($this->_context != 'MSGID') &&
+            ($this->_context != 'MSGCTXT') &&
+            ($this->_context != 'MSGID_PLURAL') &&
+            ($this->_context != 'MSGSTR_ARR')) {
+          // Plural message strings must come after msgid, msgxtxt,
+          // msgid_plural, or other msgstr[] entries.
+          $this->_errors[] = $t('The translation stream %uri contains an error: "msgstr[]" is unexpected on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        // Ensure the plurality is terminated.
+        if (strpos($line, ']') === FALSE) {
+          $this->_errors[] = $t('The translation stream %uri contains an error: invalid format for "msgstr[]" on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        // Extract the plurality.
+        $frombracket = strstr($line, '[');
+        $this->_current_plural_index = substr($frombracket, 1, strpos($frombracket, ']') - 1);
+
+        // Skip to the next whitespace and trim away any further whitespace,
+        // bringing $line to the message text only.
+        $line = trim(strstr($line, " "));
+
+        $quoted = $this->parseQuoted($line);
+        if ($quoted === FALSE) {
+          // The string must be quoted.
+          $this->_errors[] = $t('The translation stream %uri contains an error: invalid format for "msgstr[]" on line %line.', $log_vars);
+          return FALSE;
+        }
+        if (!isset($this->_current_item['msgstr']) || !is_array($this->_current_item['msgstr'])) {
+          $this->_current_item['msgstr'] = array();
+        }
+
+        $this->_current_item['msgstr'][$this->_current_plural_index] = $quoted;
+
+        $this->_context = 'MSGSTR_ARR';
+        return;
+      }
+      elseif (!strncmp("msgstr", $line, 6)) {
+        // A string pair for an msgidid (with optional context).
+
+        if (($this->_context != 'MSGID') && ($this->_context != 'MSGCTXT')) {
+          // Strings are only valid within an id or context scope.
+          $this->_errors[] = $t('The translation stream %uri contains an error: "msgstr" is unexpected on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        // Remove 'msgstr' and trim away away whitespaces.
+        $line = trim(substr($line, 6));
+
+        // Only the msgstr string is left, parse it.
+        $quoted = $this->parseQuoted($line);
+        if ($quoted === FALSE) {
+          // The string must be quoted.
+          $this->_errors[] = $t('The translation stream %uri contains an error: invalid format for "msgstr" on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        $this->_current_item['msgstr'] = $quoted;
+
+        $this->_context = 'MSGSTR';
+        return;
+      }
+      elseif ($line != '') {
+        // Anything that is not a token may be a continuation of a previous token.
+
+        $quoted = $this->parseQuoted($line);
+        if ($quoted === FALSE) {
+          // This string must be quoted.
+          $this->_errors[] = $t('The translation stream %uri contains an error: string continuation expected on line %line.', $log_vars);
+          return FALSE;
+        }
+
+        // Append the string to the current item.
+        if (($this->_context == 'MSGID') || ($this->_context == 'MSGID_PLURAL')) {
+          if (is_array($this->_current_item['msgid'])) {
+            // Add string to last array element for plural sources.
+            $last_index = count($this->_current_item['msgid']) - 1;
+            $this->_current_item['msgid'][$last_index] .= $quoted;
+          }
+          else {
+            // Singular source, just append the string.
+            $this->_current_item['msgid'] .= $quoted;
+          }
+        }
+        elseif ($this->_context == 'MSGCTXT') {
+          // Multiline context name.
+          $this->_current_item['msgctxt'] .= $quoted;
+        }
+        elseif ($this->_context == 'MSGSTR') {
+          // Multiline translation string.
+          $this->_current_item['msgstr'] .= $quoted;
+        }
+        elseif ($this->_context == 'MSGSTR_ARR') {
+          // Multiline plural translation string.
+          $this->_current_item['msgstr'][$this->_current_plural_index] .= $quoted;
+        }
+        else {
+          // No valid context to append to.
+          $this->_errors[] = $t('The translation stream %uri contains an error: unexpected string on line %line.', $log_vars);
+          return FALSE;
+        }
+        return;
+      }
+    }
+
+    // Empty line read or EOF of PO stream, close out the last entry.
+    if (($this->_context == 'MSGSTR') || ($this->_context == 'MSGSTR_ARR')) {
+      $this->setItemFromArray($this->_current_item);
+      $this->_current_item = array();
+    }
+    elseif ($this->_context != 'COMMENT') {
+      $this->_errors[] = $t('The translation stream %uri ended unexpectedly at line %line.', $log_vars);
+      return FALSE;
+    }
+  }
+
+  /**
+   * Store the parsed values as a PoItem object.
+   */
+  public function setItemFromArray($value) {
+    $plural = FALSE;
+
+    $comments = '';
+    if (isset($value['#'])) {
+      $comments = $this->shortenComments($value['#']);
+    }
+
+    if (is_array($value['msgstr'])) {
+      // Sort plural variants by their form index.
+      ksort($value['msgstr']);
+      $plural = TRUE;
+    }
+
+    $item = new PoItem();
+    $item->setContext(isset($value['msgctxt']) ? $value['msgctxt'] : '');
+    $item->setSource($value['msgid']);
+    $item->setTranslation($value['msgstr']);
+    $item->setPlural($plural);
+    $item->setComment($comments);
+    $item->setLangcode($this->_langcode);
+
+    $this->_last_item = $item;
+
+    $this->_context = 'COMMENT';
+  }
+
+  /**
+   * Parses a string in quotes.
+   *
+   * @param $string
+   *   A string specified with enclosing quotes.
+   *
+   * @return
+   *   The string parsed from inside the quotes.
+   */
+  function parseQuoted($string) {
+    if (substr($string, 0, 1) != substr($string, -1, 1)) {
+      // Start and end quotes must be the same.
+      return FALSE;
+    }
+    $quote = substr($string, 0, 1);
+    $string = substr($string, 1, -1);
+    if ($quote == '"') {
+      // Double quotes: strip slashes.
+      return stripcslashes($string);
+    }
+    elseif ($quote == "'") {
+      // Simple quote: return as-is.
+      return $string;
+    }
+    else {
+      // Unrecognized quote.
+      return FALSE;
+    }
+  }
+
+  /**
+   * Generates a short, one-string version of the passed comment array.
+   *
+   * @param $comment
+   *   An array of strings containing a comment.
+   *
+   * @return
+   *   Short one-string version of the comment.
+   */
+  private function shortenComments($comment) {
+    $comm = '';
+    while (count($comment)) {
+      $test = $comm . substr(array_shift($comment), 1) . ', ';
+      if (strlen($comm) < 130) {
+        $comm = $test;
+      }
+      else {
+        break;
+      }
+    }
+    return trim(substr($comm, 0, -2));
+  }
+
+}
diff --git a/core/lib/Drupal/Component/Gettext/PoStreamWriter.php b/core/lib/Drupal/Component/Gettext/PoStreamWriter.php
new file mode 100644
index 0000000000000000000000000000000000000000..d066307d83f7d23d80d492c6561d8bb9e3127e4c
--- /dev/null
+++ b/core/lib/Drupal/Component/Gettext/PoStreamWriter.php
@@ -0,0 +1,168 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Component\Gettext\PoStreamWriter.
+ */
+
+namespace Drupal\Component\Gettext;
+
+use Drupal\Component\Gettext\PoHeader;
+use Drupal\Component\Gettext\PoItem;
+use Drupal\Component\Gettext\PoReaderInterface;
+use Drupal\Component\Gettext\PoWriterInterface;
+use Drupal\Component\Gettext\PoStreamInterface;
+
+/**
+ * Defines a Gettext PO stream writer.
+ */
+class PoStreamWriter implements PoWriterInterface, PoStreamInterface {
+
+  /**
+   * URI of the PO stream that is being written.
+   *
+   * @var string
+   */
+  private $_uri;
+
+  /**
+   * The Gettext PO header.
+   *
+   * @var Drupal\Component\Gettext\PoHeader
+   */
+  private $_header;
+
+  /**
+   * File handle of the current PO stream.
+   *
+   * @var resource
+   */
+  private $_fd;
+
+  /**
+   * Get the PO header of the current stream.
+   *
+   * @return Drupal\Component\Gettext\PoHeader
+   *   The Gettext PO header.
+   */
+  public function getHeader() {
+    return $this->_header;
+  }
+
+  /**
+   * Set the PO header for the current stream.
+   *
+   * @param Drupal\Component\Gettext\PoHeader $header
+   *   The Gettext PO header to set.
+   */
+  public function setHeader(PoHeader $header) {
+    $this->_header = $header;
+  }
+
+  /**
+   * Get the current language code used.
+   *
+   * @return string
+   *   The language code.
+   */
+  public function getLangcode() {
+    return $this->_langcode;
+  }
+
+  /**
+   * Set the language code.
+   *
+   * @param string $langcode
+   *   The language code.
+   */
+  public function setLangcode($langcode) {
+    $this->_langcode = $langcode;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoStreamInterface::open().
+   */
+  public function open() {
+    // Open in write mode. Will overwrite the stream if it already exists.
+    $this->_fd = fopen($this->getURI(), 'w');
+    // Write the header at the start.
+    $this->writeHeader();
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoStreamInterface::close().
+   *
+   * @throws Exception
+   *   If the stream is not open.
+   */
+  public function close() {
+    if ($this->_fd) {
+      fclose($this->_fd);
+    }
+    else {
+      throw new Exception('Cannot close stream that is not open.');
+    }
+  }
+
+  /**
+   * Write data to the stream.
+   *
+   * @param string $data
+   *   Piece of string to write to the stream. If the value is not directly a
+   *   string, casting will happen in writing.
+   *
+   * @throws Exception
+   *   If writing the data is not possible.
+   */
+  private function write($data) {
+    $result = fputs($this->_fd, $data);
+    if ($result === FALSE) {
+      throw new Exception('Unable to write data: ' . substr($data, 0, 20));
+    }
+  }
+
+  /**
+   * Write the PO header to the stream.
+   */
+  private function writeHeader() {
+    $this->write($this->_header);
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoWriterInterface::writeItem().
+   */
+  public function writeItem(PoItem $item) {
+    $this->write($item);
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoWriterInterface::writeItems().
+   */
+  public function writeItems(PoReaderInterface $reader, $count = -1) {
+    $forever = $count == -1;
+    while (($count-- > 0 || $forever) && ($item = $reader->readItem())) {
+      $this->writeItem($item);
+    }
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoStreamInterface::getURI().
+   *
+   * @throws Exception
+   *   If the URI is not set.
+   */
+  public function getURI() {
+    if (empty($this->_uri)) {
+      throw new Exception('No URI set.');
+    }
+    return $this->_uri;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoStreamInterface::setURI().
+   */
+  public function setURI($uri) {
+    $this->_uri = $uri;
+  }
+
+}
diff --git a/core/lib/Drupal/Component/Gettext/PoWriterInterface.php b/core/lib/Drupal/Component/Gettext/PoWriterInterface.php
new file mode 100644
index 0000000000000000000000000000000000000000..2a2348fe46a81143856f3d824b2fd4bb1cba05a3
--- /dev/null
+++ b/core/lib/Drupal/Component/Gettext/PoWriterInterface.php
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Component\Gettext\PoWriterInterface.
+ */
+
+namespace Drupal\Component\Gettext;
+
+use Drupal\Component\Gettext\PoMetadataInterface;
+use Drupal\Component\Gettext\PoItem;
+
+/**
+ * Shared interface definition for all Gettext PO Writers.
+ */
+interface PoWriterInterface extends PoMetadataInterface {
+
+  /**
+   * Writes the given item.
+   *
+   * @param PoItem $item
+   *   One specific item to write.
+   */
+  function writeItem(PoItem $item);
+
+  /**
+   * Writes all or the given amount of items.
+   *
+   * @param PoReaderInterface $reader
+   *   Reader to read PoItems from.
+   * @param $count
+   *   Amount of items to read from $reader to write. If -1, all items are
+   *   read from $reader.
+   */
+  function writeItems(PoReaderInterface $reader, $count = -1);
+}
diff --git a/core/modules/locale/lib/Drupal/locale/Gettext.php b/core/modules/locale/lib/Drupal/locale/Gettext.php
new file mode 100644
index 0000000000000000000000000000000000000000..f3ba3b9f20c0a187b22b9e15d3013e139a6df809
--- /dev/null
+++ b/core/modules/locale/lib/Drupal/locale/Gettext.php
@@ -0,0 +1,108 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\locale\Gettext.
+ */
+
+namespace Drupal\locale;
+
+use Drupal\Component\Gettext\PoStreamReader;
+use Drupal\Component\Gettext\PoMemoryWriter;
+use Drupal\locale\PoDatabaseWriter;
+
+/**
+ * Static class providing Drupal specific Gettext functionality.
+ *
+ * The operations are related to pumping data from a source to a destination,
+ * for example:
+ * - Remote files http://*.po to memory
+ * - File public://*.po to database
+ */
+class Gettext {
+
+  /**
+   * Reads the given Gettext PO files into a data structure.
+   *
+   * @param string $langcode
+   *   Language code string.
+   * @param array $files
+   *   List of file objects with uri properties pointing to read.
+   *
+   * @return array
+   *   Structured array as produced by a PoMemoryWriter.
+   *
+   * @see Drupal\Component\Gettext\PoMemoryWriter
+   */
+  static function filesToArray($langcode, array $files) {
+    $writer = new PoMemoryWriter();
+    $writer->setLangcode($langcode);
+    foreach ($files as $file) {
+      $reader = new PoStreamReader();
+      $reader->setURI($file->uri);
+      $reader->setLangcode($langcode);
+      $reader->open();
+      $writer->writeItems($reader, -1);
+    }
+    return $writer->getData();
+  }
+
+  /**
+   * Reads the given PO files into the database.
+   *
+   * @param stdClass $file
+   *   File object with an uri property pointing at the file's path.
+   * @param string $langcode
+   *   Language code string.
+   * @param array $overwrite_options
+   *   Overwrite options array as defined in Drupal\locale\PoDatabaseWriter.
+   * @param boolean $customized
+   *   Flag indicating whether the string imported from $file are customized
+   *   translations or come from a community source. Use LOCALE_CUSTOMIZED or
+   *   LOCALE_NOT_CUSTOMIZED.
+   *
+   * @return array
+   *   Report array as defined in Drupal\locale\PoDatabaseWriter.
+   *
+   * @see Drupal\locale\PoDatabaseWriter
+   */
+  static function fileToDatabase($file, $langcode, $overwrite_options, $customized = LOCALE_NOT_CUSTOMIZED) {
+    // Instantiate and initialize the stream reader for this file.
+    $reader = new PoStreamReader();
+    $reader->setLangcode($langcode);
+    $reader->setURI($file->uri);
+
+    try {
+      $reader->open();
+    }
+    catch (Exception $exception) {
+      throw $exception;
+    }
+
+    $header = $reader->getHeader();
+    if (!$header) {
+      throw new Exception('Missing or malformed header.');
+    }
+
+    // Initialize the database writer.
+    $writer = new PoDatabaseWriter();
+    $writer->setLangcode($langcode);
+    $options = array(
+      'overwrite_options' => $overwrite_options,
+      'customized' => $customized,
+    );
+    $writer->setOptions($options);
+    $writer->setHeader($header);
+
+    // Attempt to pipe all items from the file to the database.
+    try {
+      $writer->writeItems($reader, -1);
+    }
+    catch (Exception $exception) {
+      throw $exception;
+    }
+
+    // Report back with an array of status information.
+    return $writer->getReport();
+  }
+}
diff --git a/core/modules/locale/lib/Drupal/locale/PoDatabaseReader.php b/core/modules/locale/lib/Drupal/locale/PoDatabaseReader.php
new file mode 100644
index 0000000000000000000000000000000000000000..c0dfc2f2ff57c4847afd5a8181d7a9943cb4c4a9
--- /dev/null
+++ b/core/modules/locale/lib/Drupal/locale/PoDatabaseReader.php
@@ -0,0 +1,180 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\locale\PoDatabaseReader.
+ */
+
+namespace Drupal\locale;
+
+use Drupal\Component\Gettext\PoHeader;
+use Drupal\Component\Gettext\PoItem;
+use Drupal\Component\Gettext\PoReaderInterface;
+
+/**
+ * Gettext PO reader working with the locale module database.
+ */
+class PoDatabaseReader implements PoReaderInterface {
+
+  /**
+   * An associative array indicating which type of strings should be read.
+   *
+   * Elements of the array:
+   *  - not_customized: boolean indicating if not customized strings should be
+   *    read.
+   *  - customized: boolean indicating if customized strings should be read.
+   *  - no_translated: boolean indicating if non-translated should be read.
+   *
+   * The three options define three distinct sets of strings, which combined
+   * cover all strings.
+   *
+   * @var array
+   */
+  private $_options;
+
+  /**
+   * Language code of the language being read from the database.
+   *
+   * @var string
+   */
+  private $_langcode;
+
+  /**
+   * Store the result of the query so it can be iterated later.
+   *
+   * @var resource
+   */
+  private $_result;
+
+  /**
+   * Constructor, initializes with default options.
+   */
+  function __construct() {
+    $this->setOptions(array());
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::getLangcode().
+   */
+  public function getLangcode() {
+    return $this->_langcode;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::setLangcode().
+   */
+  public function setLangcode($langcode) {
+    $this->_langcode = $langcode;
+  }
+
+  /**
+   * Get the options used by the reader.
+   */
+  function getOptions() {
+    return $this->_options;
+  }
+
+  /**
+   * Set the options for the current reader.
+   */
+  function setOptions(array $options) {
+    $options += array(
+      'customized' => FALSE,
+      'not_customized' => FALSE,
+      'not_translated' => FALSE,
+    );
+    $this->_options = $options;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::getHeader().
+   */
+  function getHeader() {
+    return new PoHeader($this->getLangcode());
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::setHeader().
+   *
+   * @throws Exception
+   *   Always, because you cannot set the PO header of a reader.
+   */
+  function setHeader(PoHeader $header) {
+    throw new Exception('You cannot set the PO header in a reader.');
+  }
+
+  /**
+   * Builds and executes a database query based on options set earlier.
+   */
+  private function buildQuery() {
+    $langcode = $this->_langcode;
+    $options = $this->_options;
+
+    if (array_sum($options) == 0) {
+      // If user asked to not include anything in the translation files,
+      // that would not make sense, so just fall back on providing a template.
+      $langcode = NULL;
+    }
+
+    // Build and execute query to collect source strings and translations.
+    $query = db_select('locales_source', 's');
+    if (!empty($langcode)) {
+      if ($options['not_translated']) {
+        // Left join to keep untranslated strings in.
+        $query->leftJoin('locales_target', 't', 's.lid = t.lid AND t.language = :language', array(':language' => $langcode));
+      }
+      else {
+        // Inner join to filter for only translations.
+        $query->innerJoin('locales_target', 't', 's.lid = t.lid AND t.language = :language', array(':language' => $langcode));
+      }
+      if ($options['customized']) {
+        if (!$options['not_customized']) {
+          // Filter for customized strings only.
+          $query->condition('t.customized', LOCALE_CUSTOMIZED);
+        }
+        // Else no filtering needed in this case.
+      }
+      else {
+        if ($options['not_customized']) {
+          // Filter for non-customized strings only.
+          $query->condition('t.customized', LOCALE_NOT_CUSTOMIZED);
+        }
+        else {
+          // Filter for strings without translation.
+          $query->isNull('t.translation');
+        }
+      }
+      $query->fields('t', array('translation'));
+    }
+    else {
+      $query->leftJoin('locales_target', 't', 's.lid = t.lid');
+    }
+    $query->fields('s', array('lid', 'source', 'context', 'location'));
+
+    $this->_result = $query->execute();
+  }
+
+  /**
+   * Get the database result resource for the given language and options.
+   */
+  private function getResult() {
+    if (!isset($this->_result)) {
+      $this->buildQuery();
+    }
+    return $this->_result;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoReaderInterface::readItem().
+   */
+  function readItem() {
+    $result = $this->getResult();
+    $values = $result->fetchAssoc();
+    if ($values) {
+      $poItem = new PoItem();
+      $poItem->setFromArray($values);
+      return $poItem;
+    }
+  }
+
+}
diff --git a/core/modules/locale/lib/Drupal/locale/PoDatabaseWriter.php b/core/modules/locale/lib/Drupal/locale/PoDatabaseWriter.php
new file mode 100644
index 0000000000000000000000000000000000000000..33f05d9f9d7c648bcda21743dc05c21b62eba33c
--- /dev/null
+++ b/core/modules/locale/lib/Drupal/locale/PoDatabaseWriter.php
@@ -0,0 +1,306 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\locale\PoDatabaseWriter.
+ */
+
+namespace Drupal\locale;
+
+use Drupal\Component\Gettext\PoHeader;
+use Drupal\Component\Gettext\PoItem;
+use Drupal\Component\Gettext\PoReaderInterface;
+use Drupal\Component\Gettext\PoWriterInterface;
+
+/**
+ * Gettext PO writer working with the locale module database.
+ */
+class PoDatabaseWriter implements PoWriterInterface {
+
+  /**
+   * An associative array indicating what data should be overwritten, if any.
+   *
+   * Elements of the array:
+   * - override_options
+   *   - not_customized: boolean indicating that not customized strings should
+   *     be overwritten.
+   *   - customized: boolean indicating that customized strings should be
+   *     overwritten.
+   * - customized: the strings being imported should be saved as customized.
+   *     One of LOCALE_CUSTOMIZED or LOCALE_NOT_CUSTOMIZED.
+   *
+   * @var array
+   */
+  private $_options;
+
+  /**
+   * Language code of the language being written to the database.
+   *
+   * @var string
+   */
+  private $_langcode;
+
+  /**
+   * Header of the po file written to the database.
+   *
+   * @var Drupal\Component\Gettext\PoHeader
+   */
+  private $_header;
+
+  /**
+   * Associative array summarizing the number of changes done.
+   *
+   * Keys for the array:
+   *  - additions: number of source strings newly added
+   *  - updates: number of translations updated
+   *  - deletes: number of translations deleted
+   *  - skips: number of strings skipped due to disallowed HTML
+   *
+   * @var array
+   */
+  private $_report;
+
+  /**
+   * Constructor, initialize reporting array.
+   */
+  function __construct() {
+    $this->setReport();
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::getLangcode().
+   */
+  public function getLangcode() {
+    return $this->_langcode;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::setLangcode().
+   */
+  public function setLangcode($langcode) {
+    $this->_langcode = $langcode;
+  }
+
+  /**
+   * Get the report of the write operations.
+   */
+  public function getReport() {
+    return $this->_report;
+  }
+
+  /**
+   * Set the report array of write operations.
+   *
+   * @param array $report
+   *   Associative array with result information.
+   */
+  function setReport($report = array()) {
+    $report += array(
+      'additions' => 0,
+      'updates' => 0,
+      'deletes' => 0,
+      'skips' => 0,
+    );
+    $this->_report = $report;
+  }
+
+  /**
+   * Get the options used by the writer.
+   */
+  function getOptions() {
+    return $this->_options;
+  }
+
+  /**
+   * Set the options for the current writer.
+   */
+  function setOptions(array $options) {
+    if (!isset($options['overwrite_options'])) {
+      $options['overwrite_options'] = array();
+    }
+    $options['overwrite_options'] += array(
+      'not_customized' => FALSE,
+      'customized' => FALSE,
+    );
+    $options += array(
+      'customized' => LOCALE_NOT_CUSTOMIZED,
+    );
+    $this->_options = $options;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::getHeader().
+   */
+  function getHeader() {
+    return $this->_header;
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoMetadataInterface::setHeader().
+   *
+   * Sets the header and configure Drupal accordingly.
+   *
+   * Before being able to process the given header we need to know in what
+   * context this database write is done. For this the options must be set.
+   *
+   * A langcode is required to set the current header's PluralForm.
+   *
+   * @param Drupal\Component\Gettext\PoHeader $header
+   *   Header metadata.
+   *
+   * @throws Exception
+   */
+  function setHeader(PoHeader $header) {
+    $this->_header = $header;
+    $locale_plurals = variable_get('locale_translation_plurals', array());
+
+    // Check for options.
+    $options = $this->getOptions();
+    if (empty($options)) {
+      throw new Exception("Options should be set before assigning a PoHeader.");
+    }
+    $overwrite_options = $options['overwrite_options'];
+
+    // Check for langcode.
+    $langcode = $this->_langcode;
+    if (empty($langcode)) {
+      throw new Exception("Langcode should be set before assigning a PoHeader.");
+    }
+
+    if (array_sum($overwrite_options) || empty($locale_plurals[$langcode]['plurals'])) {
+      // Get and store the plural formula if available.
+      $plural = $header->getPluralForms();
+      if (isset($plural) && $p = $header->parsePluralForms($plural)) {
+        list($nplurals, $formula) = $p;
+        $locale_plurals[$langcode] = array(
+          'plurals' => $nplurals,
+          'formula' => $formula,
+        );
+        variable_set('locale_translation_plurals', $locale_plurals);
+      }
+    }
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoWriterInterface::writeItem().
+   */
+  function writeItem(PoItem $item) {
+    if ($item->isPlural()) {
+      $item->setSource(join(LOCALE_PLURAL_DELIMITER, $item->getSource()));
+      $item->setTranslation(join(LOCALE_PLURAL_DELIMITER, $item->getTranslation()));
+    }
+    $this->importString($item);
+  }
+
+  /**
+   * Implements Drupal\Component\Gettext\PoWriterInterface::writeItems().
+   */
+  public function writeItems(PoReaderInterface $reader, $count = -1) {
+    $forever = $count == -1;
+    while (($count-- > 0 || $forever) && ($item = $reader->readItem())) {
+      $this->writeItem($item);
+    }
+  }
+
+  /**
+   * Imports one string into the database.
+   *
+   * @param Drupal\Component\Gettext\PoItem $item
+   *   The item being imported.
+   *
+   * @return int
+   *   The string ID of the existing string modified or the new string added.
+   */
+  private function importString(PoItem $item) {
+    // Initialize overwrite options if not set.
+    $this->_options['overwrite_options'] += array(
+      'not_customized' => FALSE,
+      'customized' => FALSE,
+    );
+    $overwrite_options = $this->_options['overwrite_options'];
+    $customized = $this->_options['customized'];
+
+    $context = $item->getContext();
+    $source = $item->getSource();
+    $translation = $item->getTranslation();
+
+
+    // Look up the source string and any existing translation.
+    $string = db_query("SELECT s.lid, t.customized 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", array(
+      ':source' => $source,
+      ':context' => $context,
+      ':language' => $this->_langcode,
+        ))
+        ->fetchObject();
+
+    if (!empty($translation)) {
+      // Skip this string unless it passes a check for dangerous code.
+      if (!locale_string_is_safe($translation)) {
+        watchdog('locale', 'Import of string "%string" was skipped because of disallowed or malformed HTML.', array('%string' => $translation), WATCHDOG_ERROR);
+        $this->_report['skips']++;
+        return 0;
+      }
+      elseif (isset($string->lid)) {
+        if (!isset($string->customized)) {
+          // No translation in this language.
+          db_insert('locales_target')
+            ->fields(array(
+              'lid' => $string->lid,
+              'language' => $this->_langcode,
+              'translation' => $translation,
+              'customized' => $customized,
+            ))
+            ->execute();
+
+          $this->_report['additions']++;
+        }
+        elseif ($overwrite_options[$string->customized ? 'customized' : 'not_customized']) {
+          // Translation exists, only overwrite if instructed.
+          db_update('locales_target')
+            ->fields(array(
+              'translation' => $translation,
+              'customized' => $customized,
+            ))
+            ->condition('language', $this->_langcode)
+            ->condition('lid', $string->lid)
+            ->execute();
+
+          $this->_report['updates']++;
+        }
+        return $string->lid;
+      }
+      else {
+        // No such source string in the database yet.
+        $lid = db_insert('locales_source')
+          ->fields(array(
+            'source' => $source,
+            'context' => $context,
+          ))
+          ->execute();
+
+        db_insert('locales_target')
+          ->fields(array(
+            'lid' => $lid,
+            'language' => $this->_langcode,
+            'translation' => $translation,
+            'customized' => $customized,
+          ))
+          ->execute();
+
+        $this->_report['additions']++;
+        return $lid;
+      }
+    }
+    elseif (isset($string->lid) && isset($string->customized) && $overwrite_options[$string->customized ? 'customized' : 'not_customized']) {
+      // Empty translation, remove existing if instructed.
+      db_delete('locales_target')
+        ->condition('language', $this->_langcode)
+        ->condition('lid', $string->lid)
+        ->execute();
+
+      $this->_report['deletes']++;
+      return $string->lid;
+    }
+  }
+
+}
diff --git a/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php b/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
index 6fe77c2c82e2183308fadfcffacd5c79e3b6c055..016082a8a4884c15ebbd2789699c1f91520e2530 100644
--- a/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
+++ b/core/modules/locale/lib/Drupal/locale/Tests/LocaleImportFunctionalTest.php
@@ -197,6 +197,7 @@ function testAutomaticModuleTranslationImportLanguageEnable() {
     // Ensure the translation file was automatically imported when language was
     // added.
     $this->assertText(t('One translation file imported.'), t('Language file automatically imported.'));
+    $this->assertText(t('A translation string was skipped because of disallowed or malformed HTML'), t('Language file automatically imported.'));
 
     // Ensure strings were successfully imported.
     $search = array(
@@ -206,6 +207,27 @@ function testAutomaticModuleTranslationImportLanguageEnable() {
     );
     $this->drupalPost('admin/config/regional/translate/translate', $search, t('Filter'));
     $this->assertNoText(t('No strings available.'), t('String successfully imported.'));
+
+    // Ensure multiline string was imported.
+    $search = array(
+      'string' => 'Source string for multiline translation',
+      'langcode' => $langcode,
+      'translation' => 'all',
+    );
+    $this->drupalPost('admin/config/regional/translate/translate', $search, t('Filter'));
+    $this->assertText('Multiline translation string to make sure that import works with it.', t('String successfully imported.'));
+
+    // Ensure 'Allowed HTML source string' was imported but the translation for
+    // 'Another allowed HTML source string' was not because it contains invalid
+    // HTML.
+    $search = array(
+      'string' => 'HTML source string',
+      'langcode' => $langcode,
+      'translation' => 'all',
+    );
+    $this->drupalPost('admin/config/regional/translate/translate', $search, t('Filter'));
+    $this->assertText('Allowed HTML source string', t('String successfully imported.'));
+    $this->assertNoText('Another allowed HTML source string', t('String with disallowed translation not imported.'));
   }
 
   /**
diff --git a/core/modules/locale/locale.bulk.inc b/core/modules/locale/locale.bulk.inc
index f795f993b317e85e9a8e362e40b438f30795e4f2..8a9c2fe7ecc4be06688c1fcc012147eed73c1894 100644
--- a/core/modules/locale/locale.bulk.inc
+++ b/core/modules/locale/locale.bulk.inc
@@ -5,7 +5,10 @@
  * Mass import-export and batch import functionality for Gettext .po files.
  */
 
-include_once DRUPAL_ROOT . '/core/includes/gettext.inc';
+use Drupal\Component\Gettext\PoStreamWriter;
+use Drupal\locale\Gettext;
+use Drupal\locale\PoDatabaseReader;
+
 
 /**
  * User interface for the translation import screen.
@@ -107,7 +110,39 @@ function locale_translate_import_form_submit($form, &$form_state) {
     $customized = $form_state['values']['customized'] ? LOCALE_CUSTOMIZED : LOCALE_NOT_CUSTOMIZED;
 
     // Now import strings into the language
-    if ($return = _locale_import_po($file, $language->langcode, $form_state['values']['overwrite_options'], $customized) == FALSE) {
+    try {
+      // Try to allocate enough time to parse and import the data.
+      drupal_set_time_limit(240);
+
+      $report = GetText::fileToDatabase($file, $language->langcode, $form_state['values']['overwrite_options'], $customized);
+      $additions = $report['additions'];
+      $updates = $report['updates'];
+      $deletes = $report['deletes'];
+      $skips = $report['skips'];
+
+      menu_router_rebuild();
+      // Clear cache and force refresh of JavaScript translations.
+      _locale_invalidate_js($language->langcode);
+      cache()->deletePrefix('locale:');
+
+      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' => $language->langcode, '%number' => $additions, '%update' => $updates, '%delete' => $deletes));
+      if ($skips) {
+        if (module_exists('dblog')) {
+          $skip_message = format_plural($skips, 'A translation string was skipped because of disallowed or malformed HTML. <a href="@url">See the log</a> for details.', '@count translation strings were skipped because of disallowed or malformed HTML. <a href="@url">See the log</a> for details.', array('@url' => url('admin/reports/dblog')));
+        }
+        else {
+          $skip_message = format_plural($skips, 'A translation string was skipped because of disallowed or malformed HTML. See the log for details.', '@count translation strings were skipped because of disallowed or malformed HTML. See the log for details.');
+        }
+        drupal_set_message($skip_message, 'error');
+        watchdog('locale', '@count disallowed HTML string(s) in %file', array('@count' => $skips, '%file' => $file->uri), WATCHDOG_WARNING);
+      }
+      $variables = array('%filename' => $file->filename);
+      drupal_set_message(t('The translation import of %filename is done.', $variables));
+      watchdog('locale', 'The translation import of %filename is done.', $variables);
+
+    } catch (Exception $exc) {
+      drupal_set_message(print_r($exc, TRUE));
       $variables = array('%filename' => $file->filename);
       drupal_set_message(t('The translation import of %filename failed.', $variables), 'error');
       watchdog('locale', 'The translation import of %filename failed.', $variables, WATCHDOG_ERROR);
@@ -207,7 +242,44 @@ function locale_translate_export_form_submit($form, &$form_state) {
     $language = NULL;
   }
   $content_options = isset($form_state['values']['content_options']) ? $form_state['values']['content_options'] : array();
-  _locale_export_po($language, _locale_export_po_generate($language, _locale_export_get_strings($language, $content_options)));
+  $reader = new PoDatabaseReader();
+  $languageName = '';
+  if ($language != NULL) {
+    $reader->setLangcode($language->langcode);
+    $reader->setOptions($content_options);
+    $languages = language_list();
+    $languageName = isset($languages[$language->langcode]) ? $languages[$language->langcode]->name : '';
+    $filename = $language->langcode .'.po';
+  }
+  else {
+    // Template required.
+    $filename = 'drupal.pot';
+  }
+
+  $item = $reader->readItem();
+  if (!empty($item)) {
+    $uri = tempnam('temporary://', 'po_');
+    $header = $reader->getHeader();
+    $header->setProjectName(variable_get('site_name', 'Drupal'));
+    $header->setLanguageName($languageName);
+
+    $writer = new PoStreamWriter;
+    $writer->setUri($uri);
+    $writer->setHeader($header);
+
+    $writer->open();
+    $writer->writeItem($item);
+    $writer->writeItems($reader);
+    $writer->close();
+
+    header("Content-Disposition: attachment; filename=$filename");
+    header("Content-Type: text/plain; charset=utf-8");
+    print file_get_contents($uri);
+    drupal_exit();
+  }
+  else {
+    drupal_set_message('Nothing to export.');
+  }
 }
 
 /**
@@ -257,7 +329,7 @@ function locale_translate_batch_import_files($langcode = NULL, $finish_feedback
       ->fetchAllAssoc('uri');
     foreach ($result as $uri => $info) {
       if (isset($files[$uri]) && filemtime($uri) <= $info->timestamp) {
-        // The file is already imported and it did not change since the import.
+        // The file is already imported and not changed since the last import.
         // Remove it from file list and don't import it again.
         unset($files[$uri]);
       }
@@ -318,22 +390,32 @@ function locale_translate_batch_build($files, $finish_feedback = FALSE) {
 /**
  * Perform interface translation import as a batch step.
  *
+ * The given filepath is matched against ending with '{langcode}.po'. When
+ * matched the filepath is added to batch context.
+ *
  * @param $filepath
  *   Path to a file to import.
- * @param $results
+ * @param $context
  *   Contains a list of files imported.
  */
 function locale_translate_batch_import($filepath, &$context) {
   // The filename is either {langcode}.po or {prefix}.{langcode}.po, so
   // we can extract the language code to use for the import from the end.
   if (preg_match('!(/|\.)([^\./]+)\.po$!', $filepath, $langcode)) {
-    $file = locale_translate_file_create($filepath, $langcode[2]);
-    $success = _locale_import_read_po('db-store', $file, array(), $langcode[2]);
-    if ($success == NULL) {
-      $file->langcode = $langcode[2];
+    $file = entity_create('file', array('filename' => drupal_basename($filepath), 'uri' => $filepath));
+    // We need only the last match
+    $langcode = array_pop($langcode);
+    try {
+      $report = GetText::fileToDatabase($file, $langcode, array(), LOCALE_NOT_CUSTOMIZED);
+      $file->langcode = $langcode;
+      $file->timestamp = filemtime($file->uri);
       locale_translate_update_file_history($file);
+      $context['results']['files'][$filepath] = $filepath;
+      $context['results']['stats'][$filepath] = $report;
+    } catch (Exception $exception) {
+      $context['results']['files'][$filepath] = $filepath;
+      $context['results']['failed_files'][$filepath] = $filepath;
     }
-    $context['results'][] = $filepath;
   }
 }
 
@@ -342,7 +424,30 @@ function locale_translate_batch_import($filepath, &$context) {
  */
 function locale_translate_batch_finished($success, $results) {
   if ($success) {
-    drupal_set_message(format_plural(count($results), 'One translation file imported.', '@count translation files imported.'));
+    $additions = $updates = $deletes = $skips = 0;
+    drupal_set_message(format_plural(count($results['files']), 'One translation file imported.', '@count translation files imported.'));
+    $skipped_files = array();
+    foreach ($results['stats'] as $filepath => $report) {
+      $additions += $report['additions'];
+      $updates += $report['updates'];
+      $deletes += $report['deletes'];
+      $skips += $report['skips'];
+      if ($report['skips'] > 0) {
+        $skipped_files[] = $filepath;
+      }
+    }
+    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', 'The translation was succesfully imported. %number new strings added, %update updated and %delete removed.', array('%number' => $additions, '%update' => $updates, '%delete' => $deletes));
+    if ($skips) {
+      if (module_exists('dblog')) {
+        $skip_message = format_plural($skips, 'A translation string was skipped because of disallowed or malformed HTML. <a href="@url">See the log</a> for details.', '@count translation strings were skipped because of disallowed or malformed HTML. <a href="@url">See the log</a> for details.', array('@url' => url('admin/reports/dblog')));
+      }
+      else {
+        $skip_message = format_plural($skips, 'A translation string was skipped because of disallowed or malformed HTML. See the log for details.', '@count translation strings were skipped because of disallowed or malformed HTML. See the log for details.');
+      }
+      drupal_set_message($skip_message, 'error');
+      watchdog('locale', '@count disallowed HTML string(s) in files: @files.', array('@count' => $skips, '@files' => implode(',', $skipped_files)), WATCHDOG_WARNING);
+    }
   }
 }
 
diff --git a/core/modules/locale/tests/test.xx.po b/core/modules/locale/tests/test.xx.po
index 659a6e3f12bcfd6045313e947847c0fac8d7cf74..e2db1d305dd2a5a9d6da1b9b116465f8ea464248 100644
--- a/core/modules/locale/tests/test.xx.po
+++ b/core/modules/locale/tests/test.xx.po
@@ -26,3 +26,15 @@ msgstr "samedi"
 
 msgid "Sunday"
 msgstr "dimanche"
+
+msgid "Allowed HTML source string"
+msgstr "<strong>Allowed HTML translation string</strong>"
+
+msgid "Another allowed HTML source string"
+msgstr "<script>Disallowed HTML translation string</script>"
+
+msgid "Source string for multiline translation"
+msgstr ""
+"Multiline translation string "
+"to make sure that "
+"import works with it."