filter/emoticon/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  * Filter converting emoticon texts into images
  20  *
  21  * This filter uses the emoticon settings in Site admin > Appearance > HTML settings
  22  * and replaces emoticon texts with images.
  23  *
  24  * @package    filter
  25  * @subpackage emoticon
  26  * @see        emoticon_manager
  27  * @copyright  2010 David Mudrak <david@moodle.com>
  28  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  29  */
  30
  31 defined('MOODLE_INTERNAL') || die();
  32
  33 class filter_emoticon extends moodle_text_filter {
  34
  35     /**
  36      * Internal cache used for replacing. Multidimensional array;
  37      * - dimension 1: language,
  38      * - dimension 2: theme.
  39      * @var array
  40      */
  41     protected static $emoticontexts = array();
  42
  43     /**
  44      * Internal cache used for replacing. Multidimensional array;
  45      * - dimension 1: language,
  46      * - dimension 2: theme.
  47      * @var array
  48      */
  49     protected static $emoticonimgs = array();
  50
  51     /**
  52      * Apply the filter to the text
  53      *
  54      * @see filter_manager::apply_filter_chain()
  55      * @param string $text to be processed by the text
  56      * @param array $options filter options
  57      * @return string text after processing
  58      */
  59     public function filter($text, array $options = array()) {
  60
  61         if (!isset($options['originalformat'])) {
  62             // if the format is not specified, we are probably called by {@see format_string()}
  63             // in that case, it would be dangerous to replace text with the image because it could
  64             // be stripped. therefore, we do nothing
  65             return $text;
  66         }
  67         if (in_array($options['originalformat'], explode(',', get_config('filter_emoticon', 'formats')))) {
  68             return $this->replace_emoticons($text);
  69         }
  70         return $text;
  71     }
  72
  73     ////////////////////////////////////////////////////////////////////////////
  74     // internal implementation starts here
  75     ////////////////////////////////////////////////////////////////////////////
  76
  77     /**
  78      * Replace emoticons found in the text with their images
  79      *
  80      * @param string $text to modify
  81      * @return string the modified result
  82      */
  83     protected function replace_emoticons($text) {
  84         global $CFG, $OUTPUT, $PAGE;
  85
  86         $lang = current_language();
  87         $theme = $PAGE->theme->name;
  88
  89         if (!isset(self::$emoticontexts[$lang][$theme]) or !isset(self::$emoticonimgs[$lang][$theme])) {
  90             // prepare internal caches
  91             $manager = get_emoticon_manager();
  92             $emoticons = $manager->get_emoticons();
  93             self::$emoticontexts[$lang][$theme] = array();
  94             self::$emoticonimgs[$lang][$theme] = array();
  95             foreach ($emoticons as $emoticon) {
  96                 self::$emoticontexts[$lang][$theme][] = $emoticon->text;
  97                 self::$emoticonimgs[$lang][$theme][] = $OUTPUT->render($manager->prepare_renderable_emoticon($emoticon));
  98             }
  99             unset($emoticons);
 100         }
 101
 102         if (empty(self::$emoticontexts[$lang][$theme])) { // No emoticons defined, nothing to process here.
 103             return $text;
 104         }
 105
 106         // Detect all zones that we should not handle (including the nested tags).
 107         $processing = preg_split('/(<\/?(?:span|script|pre)[^>]*>)/is', $text, 0, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
 108
 109         // Initialize the results.
 110         $resulthtml = "";
 111         $exclude = 0;
 112
 113         // Define the patterns that mark the start of the forbidden zones.
 114         $excludepattern = array('/^<script/is', '/^<span[^>]+class="nolink[^"]*"/is', '/^<pre/is');
 115
 116         // Loop through the fragments.
 117         foreach ($processing as $fragment) {
 118             // If we are not ignoring, we MUST test if we should.
 119             if ($exclude == 0) {
 120                 foreach ($excludepattern as $exp) {
 121                     if (preg_match($exp, $fragment)) {
 122                         $exclude = $exclude + 1;
 123                         break;
 124                     }
 125                 }
 126             }
 127             if ($exclude > 0) {
 128                 // If we are ignoring the fragment, then we must check if we may have reached the end of the zone.
 129                 if (strpos($fragment, '</span') !== false || strpos($fragment, '</script') !== false
 130                     || strpos($fragment, '</pre') !== false) {
 131                     $exclude -= 1;
 132                     // This is needed because of a double increment at the first element.
 133                     if ($exclude == 1) {
 134                         $exclude -= 1;
 135                     }
 136                 } else if (strpos($fragment, '<span') !== false || strpos($fragment, '<script') !== false
 137                     || strpos($fragment, '<pre') !== false) {
 138                     // If we find a nested tag we increase the exclusion level.
 139                     $exclude = $exclude + 1;
 140                 }
 141             } else if (strpos($fragment, '<span') === false ||
 142                        strpos($fragment, '</span') === false) {
 143                 // This is the meat of the code - this is run every time.
 144                 // This code only runs for fragments that are not ignored (including the tags themselves).
 145                 $fragment = str_replace(self::$emoticontexts[$lang][$theme], self::$emoticonimgs[$lang][$theme], $fragment);
 146             }
 147             $resulthtml .= $fragment;
 148         }
 149
 150         return $resulthtml;
 151     }
 152 }