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
31defined('MOODLE_INTERNAL') || die();
32
33class 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}
153