filter/multilang/filter.php

   1 <?php
   2
   3 // This file is part of Moodle - http://moodle.org/
   4 //
   5 // Moodle is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // Moodle is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 /**
  19  * @package    filter_multilang
  20  * @copyright  Gaetan Frenoy <gaetan@frenoy.net>
  21  * @copyright  2004 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
  22  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  */
  24
  25 defined('MOODLE_INTERNAL') || die();
  26
  27 // Given XML multilinguage text, return relevant text according to
  28 // current language:
  29 //   - look for multilang blocks in the text.
  30 //   - if there exists texts in the currently active language, print them.
  31 //   - else, if there exists texts in the current parent language, print them.
  32 //   - else, print the first language in the text.
  33 // Please note that English texts are not used as default anymore!
  34 //
  35 // This version is based on original multilang filter by Gaetan Frenoy,
  36 // rewritten by Eloy and skodak.
  37 //
  38 // Following new syntax is not compatible with old one:
  39 //   <span lang="XX" class="multilang">one lang</span><span lang="YY" class="multilang">another language</span>
  40
  41
  42 /**
  43  * Implementation of the Moodle filter API for the Multi-lang filter.
  44  *
  45  * @copyright  Gaetan Frenoy <gaetan@frenoy.net>
  46  * @copyright  2004 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
  47  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  48  */
  49 class filter_multilang extends moodle_text_filter {
  50     function filter($text, array $options = array()) {
  51         global $CFG;
  52
  53         // [pj] I don't know about you but I find this new implementation funny :P
  54         // [skodak] I was laughing while rewriting it ;-)
  55         // [nicolasconnault] Should support inverted attributes: <span class="multilang" lang="en"> (Doesn't work curently)
  56         // [skodak] it supports it now, though it is slower - any better idea?
  57
  58         if (empty($text) or is_numeric($text)) {
  59             return $text;
  60         }
  61
  62         if (empty($CFG->filter_multilang_force_old) and !empty($CFG->filter_multilang_converted)) {
  63             // new syntax
  64             $search = '/(<span(\s+lang="[a-zA-Z0-9_-]+"|\s+class="multilang"){2}\s*>.*?<\/span>)(\s*<span(\s+lang="[a-zA-Z0-9_-]+"|\s+class="multilang"){2}\s*>.*?<\/span>)+/is';
  65         } else {
  66             // old syntax
  67             $search = '/(<(?:lang|span) lang="[a-zA-Z0-9_-]*".*?>.*?<\/(?:lang|span)>)(\s*<(?:lang|span) lang="[a-zA-Z0-9_-]*".*?>.*?<\/(?:lang|span)>)+/is';
  68         }
  69
  70         $result = preg_replace_callback($search, [$this, 'process_match'], $text);
  71
  72         if (is_null($result)) {
  73             return $text; //error during regex processing (too many nested spans?)
  74         } else {
  75             return $result;
  76         }
  77     }
  78
  79     /**
  80      * This is the callback used by the preg_replace_callback call above.
  81      *
  82      * @param array $langblock one of the matches from the regex match.
  83      * @return string the replacement string (one of the possible translations).
  84      */
  85     protected function process_match(array $langblock): string {
  86         $searchtosplit = '/<(?:lang|span)[^>]+lang="([a-zA-Z0-9_-]+)"[^>]*>(.*?)<\/(?:lang|span)>/is';
  87
  88         if (!preg_match_all($searchtosplit, $langblock[0], $rawlanglist)) {
  89             // Skip malformed blocks.
  90             return $langblock[0];
  91         }
  92
  93         $langlist = array();
  94         foreach ($rawlanglist[1] as $index => $lang) {
  95             $lang = str_replace('-', '_', strtolower($lang)); // Normalize languages.
  96             $langlist[$lang] = $rawlanglist[2][$index];
  97         }
  98
  99         // Follow the stream of parent languages.
 100         $lang = current_language();
 101         do {
 102             if (isset($langlist[$lang])) {
 103                 return $langlist[$lang];
 104             }
 105         } while ($lang = $this->get_parent_lang($lang));
 106
 107         // If we don't find a match, default to the first provided translation.
 108         return array_shift($langlist);
 109     }
 110
 111     /**
 112      * Puts some caching around get_parent_language().
 113      *
 114      * Also handle parent == 'en' in a way that works better for us.
 115      *
 116      * @param string $lang a Moodle language code, e.g. 'fr'.
 117      * @return string the parent language.
 118      */
 119     protected function get_parent_lang(string $lang): string {
 120         static $parentcache;
 121         if (!isset($parentcache)) {
 122             $parentcache = ['en' => ''];
 123         }
 124         if (!isset($parentcache[$lang])) {
 125             $parentcache[$lang] = get_parent_language($lang);
 126             // The standard get_parent_language method returns '' for parent == 'en'.
 127             // That is less helpful for us, so change it back.
 128             if ($parentcache[$lang] === '') {
 129                 $parentcache[$lang] = 'en';
 130             }
 131         }
 132         return $parentcache[$lang];
 133     }
 134 }