Merge branch 'main' into issue-3911issue-3911

1 files changed, 0 insertions, 787 deletions

diff --git a/lib/classes/Markup.class.php b/lib/classes/Markup.class.php
deleted file mode 100644
index da040fa..0000000
--- a/lib/classes/Markup.class.php
+++ /dev/null
@@ -1,787 +0,0 @@
-<?php
-/**
- * Markup.class.php - Handling of Stud.IP- and HTML-markup.
- **
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * @category    Stud.IP
- * @copyright   (c) 2014 Stud.IP e.V.
- * @license     http://www.gnu.org/licenses/gpl-2.0.html GPL version 2
- * @since       File available since Release 3.0
- * @author      Robert Costa <rcosta@uos.de>
- */
-namespace Studip;
-
-require_once __DIR__ . '/htmlpurifier/HTMLPurifier_Injector_ClassifyLinks.php';
-require_once __DIR__ . '/htmlpurifier/HTMLPurifier_Injector_ClassifyTables.php';
-require_once __DIR__ . '/htmlpurifier/HTMLPurifier_Injector_LinkifyEmail.php';
-require_once __DIR__ . '/htmlpurifier/HTMLPurifier_Injector_TransformLinks.php';
-require_once __DIR__ . '/htmlpurifier/HTMLPurifier_Injector_Unlinkify.php';
-
-class Markup
-{
-    /**
-     * Apply markup rules and clean the text up.
-     *
-     * @param TextFormat $markup  Markup rules applied on marked-up text.
-     * @param string     $text    Marked-up text on which rules are applied.
-     * @param boolean    $trim    Trim text before applying markup rules, if TRUE.
-     *
-     * @return string  HTML code computed from marked-up text.
-     */
-    public static function apply($markup, $text, $trim)
-    {
-        return $markup->format(self::markupToHtml($text, $trim, false));
-    }
-
-    // signature for HTML entries
-    const HTML_MARKER = '<!--HTML-->';
-
-    // signature for HTML fallback entries
-    const HTML_MARKER_FALLBACK = '<!-- HTML: Insert text after this line only. -->';
-
-    // regular expression for detecting HTML signature
-    const HTML_MARKER_REGEXP = '/^\s*<!--\s*HTML.*?-->/i';
-
-    /**
-     * Return `true` if the WYSIWYG editor is enabled for this user.
-     * @deprecated since Stud.IP 5.5
-     *
-     * @return boolean  always returns `true`.
-     */
-    public static function editorEnabled()
-    {
-        return true;
-    }
-
-    /**
-     * Return `true` for HTML code and `false` for plain text.
-     *
-     * HTML code must either match `HTML_MARKER_REGEXP` or begin
-     * with '<' and end with '>' (leading and trailing whitespace
-     * is ignored). Everything else is considered to be plain
-     * text.
-     *
-     * @param string $text  HTML code or plain text.
-     *
-     * @return boolean  `true` for HTML code, `false` for plain text.
-     */
-    public static function isHtml($text)
-    {
-        return self::hasHtmlMarker($text);
-    }
-
-    /**
-     * Return `true` for Stud.IP-HTML and `false` otherwise.
-     *
-     * Stud.IP-HTML is HTML that can contain Stud.IP Markup.
-     *
-     * Stud.IP-HTML must match Stud.IP 3.2's HTML marker.
-     * Leading and trailing whitespace is ignored.
-     *
-     * Everything else is considered not Stud.IP-HTML. In other
-     * words, if it's not Stud.IP-HTML it might be everything
-     * from plain text to binary code. But usually it's either
-     * Stud.IP markup or plain HTML code, then.
-     *
-     * @param string $text  Text that is or isn't Stud.IP-HTML.
-     *
-     * @return boolean  `true` for Stud.IP-HTML
-     */
-    public static function isHtmlFallback($text)
-    {
-        $text = trim($text);
-
-        // it's not fallback if the new HTML marker is detected
-        if (MarkupPrivate\Text\startsWith($text, self::HTML_MARKER)) {
-            return false;
-        }
-
-        // it's Stud.IP-HTML if Stud.IP 3.2's HTML marker is detected
-        if (MarkupPrivate\Text\startsWith($text, self::HTML_MARKER_FALLBACK)) {
-            return true;
-        }
-
-        return false;
-    }
-
-    /**
-     * Return `true` for HTML code and `false` for plain text.
-     *
-     * HTML code must start with a match for `HTML_MARKER_REGEXP`.
-     *
-     * @param string $text  HTML code or plain text.
-     *
-     * @return boolean  `true` for HTML code, `false` for plain text.
-     */
-    public static function hasHtmlMarker($text)
-    {
-        return preg_match(self::HTML_MARKER_REGEXP, $text);
-    }
-
-    /**
-     * Mark a given text as HTML code.
-     *
-     * No sanity-checking is done on the given text. It is simply
-     * marked up so to be identified by Markup::isHtml as HTML
-     * code.
-     *
-     * @param string $text  The text to be marked up as HTML code.
-     *
-     * @return string  The text marked up as HTML code.
-     */
-    public static function markAsHtml($text)
-    {
-        // NOTE keep this function in sync with the JavaScript
-        // function markAsHtml in WyswygHtmlHead.php
-        if (self::hasHtmlMarker($text) || trim($text) === '') {
-            return $text; // marker already set, don't set twice
-        }
-        return self::HTML_MARKER . $text;
-    }
-
-    /**
-     * Apply markup rules after running text through HTML ready.
-     *
-     * @param TextFormat $markup  Markup rules applied on marked-up text.
-     * @param string     $text    Marked-up text on which rules are applied.
-     * @param boolean    $trim    Trim text before applying markup rules, if TRUE.
-     *
-     * @return string  HTML code computed from marked-up text.
-     */
-    private static function markupHtmlReady($markup, $text, $trim)
-    {
-        return str_replace("\n", '<br>', self::markupText(
-            $markup, self::htmlReady(self::unixEOL($text), $trim)));
-    }
-
-    /**
-     * Convert line break to Unix format.
-     *
-     * @param string $text  Text with possibly mixed line breaks (Win, Mac, Unix).
-     *
-     * @return string  Text with Unix line breaks only.
-     */
-    private static function unixEOL($text)
-    {
-        return preg_replace("/\r\n?/", "\n", $text);
-    }
-
-    /**
-     * Apply markup rules on plain text.
-     *
-     * @param TextFormat $markup  Markup rules applied on marked-up text.
-     * @param string     $text    Marked-up text on which rules are applied.
-     *
-     * @return string  HTML code computed from marked-up text.
-     */
-    private static function markupText($markup, $text)
-    {
-        return symbol($markup->format($text));
-    }
-
-    /**
-     * Call HTMLPurifier to create safe HTML.
-     *
-     * @param   string  $dirty_html  Unsafe or 'uncleaned' HTML code.
-     * @param   boolean $autoformat  Apply the AutoFormat rules
-     * @return  string              Clean and safe HTML code.
-     */
-    private static function purify($dirty_html, $autoformat = true)
-    {
-        $purifier = self::createPurifier($autoformat);
-
-        return $purifier->purify($dirty_html);
-    }
-
-    /**
-     * Call HTMLPurifier to filter the HTML code (if the source is detected
-     * to contain HTML, returns the argument unchanged otherwise). The HTML
-     * marker is restored afterwards, if it was present.
-     *
-     * @param   string  $dirty_html  Unsafe or 'uncleaned' HTML code.
-     * @return  string              Clean and safe HTML code.
-     */
-    public static function purifyHtml($html)
-    {
-        if ($html instanceof \I18NString) {
-            $base = self::purifyHtml($html->original());
-            $lang = $html->toArray();
-
-            foreach ($lang as &$value) {
-                $value = self::purifyHtml($value);
-            }
-
-            return new \I18NString($base, $lang);
-        }
-
-        if (self::isHtml($html)) {
-            $html = self::markAsHtml(self::purify($html));
-        }
-
-        return $html;
-    }
-
-    /**
-     * Create HTML purifier instance with Stud.IP-specific configuration.
-     *
-     * @param  boolean $autoformat  Apply the AutoFormat rules
-     * @return \HTMLPurifier A new instance of the HTML purifier.
-     */
-    private static function createPurifier($autoformat)
-    {
-        $config = \HTMLPurifier_Config::createDefault();
-        $config->set('Cache.SerializerPath', $GLOBALS['TMP_PATH']);
-        $config->set('Core.RemoveInvalidImg', true);
-
-        // restrict allowed HTML tags and attributes
-        //
-        // note that changes here should also be reflected in CKEditor's
-        // settings!!
-        //
-        // NOTE The list could be restricted even further by allowing only
-        // specific values for some attributes and CSS styles, but that is not
-        // directly supported by HTMLPurifier and would need to be implemented
-        // with a filter similar to ClassifyLinks.
-        //
-        // This is a list of further restrictions that can/should be introduced
-        // at a later time point maybe, if possible:
-        //
-        // - always open external links in a new tab or window
-        //   a[class="link-extern" href="..." target="_blank"]
-        // - only allow left margin and horizontal text alignment to be set in
-        //   divs (NOTE maybe remove these two features completely?):
-        //   div[style="margin-left:(40|80|...)px; text-align:(center|right|justify)"]
-        // - img[style] should only allow float:left or float:right
-        // - only allow text color and background color to be set in a span's
-        //   style attribute (NOTE 'wiki-links' are currently set here due to
-        //   implementation difficulties, but probably this should be
-        //   changed...):
-        //   span[style="color:(#000000|#800000|...);
-        //               background-color:(#000000|#800000|...)"
-        //        class="wiki-link"]
-        // - tables should always have the class "content" (it should not be
-        //   optional and no other class should be set):
-        //   table[class="content"]
-        // - table headings should have a column and/or a row scope or no scope
-        //   at all, but nothing else:
-        //   th[scope="(col | row)"]
-        // - fonts: only Stud.IP-specific fonts should be allowed
-        //
-        $config->set('HTML.Allowed', '
-            a[class|href|target|rel|name|id]
-            audio[controls|src|height|width|style]
-            big
-            blockquote
-            br
-            caption
-            code[class]
-            div[class|style]
-            em
-            figure[class|style]
-            figcaption
-            h1
-            h2
-            h3
-            h4
-            h5
-            h6
-            hr
-            i
-            img[alt|src|height|width|class|style]
-            li
-            ol[reversed|start|style]
-            p[style]
-            pre[class]
-            span[style|class]
-            strong
-            u
-            ul[style]
-            s
-            small
-            sub
-            sup
-            table[class|style]
-            tbody
-            td[colspan|rowspan|style]
-            thead
-            th[colspan|rowspan|style|scope]
-            tr
-            tt
-            video[controls|src|height|width|style]
-        ');
-
-        $config->set('Attr.AllowedFrameTargets', ['_blank']);
-        $config->set('Attr.AllowedRel', ['nofollow']);
-        $config->set('Attr.EnableID', true);
-        $config->set('Attr.AllowedClasses', [
-            'author',
-            'content',
-            'image',
-            'image-style-side',
-            'image_resized',
-            'language-cpp',
-            'language-css',
-            'language-diff',
-            'language-java',
-            'language-javascript',
-            'language-json',
-            'language-php',
-            'language-python',
-            'language-ruby',
-            'language-scss',
-            'language-sql',
-            'language-xml',
-            'link-extern',
-            'link-intern',
-            'math-tex',
-            'table',
-            'usercode',
-            'wiki-link'
-        ]);
-        $config->set('CSS.AllowedFonts', [
-            'serif',
-            'sans-serif',
-            'monospace',
-            'cursive'
-        ]);
-        $config->set('CSS.AllowedProperties', [
-            'margin-left',
-            'text-align',
-            'width',
-            'height',
-            'color',
-            'background-color', // needed by span, td
-            'border-color',
-            'border-style',
-            'float',
-            'border'
-        ]);
-        $config->set('CSS.MaxImgLength', null);
-
-        if ($autoformat) {
-            $config->set('AutoFormat.Linkify', true);
-            $config->set('AutoFormat.Custom', [
-                'ClassifyLinks',
-                'ClassifyTables',
-                'LinkifyEmail'
-            ]);
-            $config->set('AutoFormat.RemoveSpansWithoutAttributes', true);
-        } else {
-            $config->set('AutoFormat.Custom', ['TransformLinks']);
-        }
-
-        // avoid <img src="evil_CSRF_stuff">
-        $def = $config->getHTMLDefinition(true);
-        $img = $def->addBlankElement('img');
-        $img->attr_transform_post[]
-            = new MarkupPrivate\Purifier\AttrTransform_Image_Source();
-
-        $def->addElement('audio', 'Inline', 'Flow', 'Common', [
-              'src*' => 'URI',
-              'width' => 'Length',
-              'height' => 'Length',
-              'controls' => 'Text',     // Bool triggers bug in HTMLPurifier
-        ]);
-
-        $def->addElement('video', 'Inline', 'Flow', 'Common', [
-              'src*' => 'URI',
-              'width' => 'Length',
-              'height' => 'Length',
-              'controls' => 'Text',     // Bool triggers bug in HTMLPurifier
-        ]);
-
-        $def->addElement('figcaption', 'Inline', 'Flow', 'Common');
-        $def->addElement('figure', 'Block', 'Optional: (figcaption, Flow) | (Flow, figcaption) | Flow', 'Common');
-
-        $def->addAttribute('ol', 'reversed', 'Bool');
-        $def->addAttribute('ol', 'style', 'Text');
-        $def->addAttribute('ul', 'style', 'Text');
-
-        return new \HTMLPurifier($config);
-    }
-
-    /**
-     * Convert special characters to HTML entities, and clean up.
-     *
-     * @param  string  $text  This text's special chars will be converted.
-     * @param  boolean $trim  Trim text before applying markup rules, if TRUE.
-     * @param  boolean $br    Replace newlines by <br>, if TRUE.
-     * @param  boolean $double_encode  Encode existing HTML entities, if TRUE.
-     * @return string         The converted string.
-     */
-    public static function htmlReady(
-        $text, $trim = true, $br = false, $double_encode = true
-    ) {
-        $text = htmlspecialchars($text, ENT_QUOTES, 'utf-8', $double_encode);
-
-        if ($trim) {
-            $text = trim($text);
-        }
-        if ($br) { // fix newlines
-            $text = nl2br($text, false);
-        }
-        return $text;
-    }
-
-    /**
-     * Prepare text for wysiwyg (if enabled), otherwise convert special
-     * characters using htmlReady.
-     *
-     * @param  string  $text  The text.
-     * @param  boolean $trim  Trim text before applying markup rules, if TRUE.
-     * @param  boolean $br    Replace newlines by <br>, if TRUE and wysiwyg editor disabled.
-     * @param  boolean $double_encode  Encode existing HTML entities, if TRUE and wysiwyg editor disabled.
-     * @return string         The converted string.
-     */
-    public static function wysiwygReady(
-        $text, $trim = true, $br = false, $double_encode = true
-    ) {
-        if (self::editorEnabled()) {
-            $text = self::markupToHtml($text, $trim);
-        }
-        return self::htmlReady($text, $trim, $br, $double_encode);
-    }
-
-    /**
-     * Convert Stud.IP markup (possibly mixed with HTML if fallback mode is
-     * enabled) to editable HTML. Pure HTML will only run through the purifier.
-     *
-     * @param  string  $text  The text.
-     * @param  boolean $trim  Trim text before applying markup rules, if TRUE.
-     * @param  boolean $mark  Mark result text as HTML, if TRUE.
-     * @return string         The converted string.
-     */
-    public static function markupToHtml($text, $trim = true, $mark = true)
-    {
-        if (!trim($text)) {
-            return $text;
-        }
-        if (self::isHtml($text)) {
-            $is_fallback = self::isHtmlFallback($text);
-            $text = self::purify($text, false);
-
-            if ($is_fallback) {
-                $text = self::markupText(new \StudipCoreFormat(), $text);
-            }
-        } else {
-            $text = self::markupHtmlReady(new \StudipCoreFormat(), $text, $trim);
-        }
-
-        return $mark ? self::markAsHtml($text) : $text;
-    }
-
-    /**
-     * Call HTMLPurifier to remove all HTML tags from the string (if the source
-     * is detected to contain HTML, returns the argument unchanged otherwise).
-     *
-     * @param   string  $html  HTML code to filter
-     * @return  string         The converted string.
-     */
-    public static function removeHtml($html)
-    {
-        if (self::isHtml($html)) {
-            $config = \HTMLPurifier_Config::createDefault();
-            $config->set('Cache.SerializerPath', $GLOBALS['TMP_PATH']);
-            $config->set('HTML.Allowed', 'a[href],img[alt|src],br');
-            $config->set('AutoFormat.Custom', ['Unlinkify']);
-
-            $html = str_replace('</li>', '</li><br>', $html);
-            $html = str_replace('</ol>', '</ol><br>', $html);
-            $html = str_replace('</ul>', '</ul><br>', $html);
-            $html = str_replace('</tr>', '</tr><br>', $html);
-            $html = str_replace('</p>', '</p><br><br>', $html);
-            $html = str_replace('</div>', '</div><br><br>', $html);
-
-            $purifier = new \HTMLPurifier($config);
-            $html = $purifier->purify($html);
-
-            // Replace new lines with simple line break; twice because we don't
-            // want to create unneccessary white space if a <br /> is followed
-            // by a new line
-            $html = str_replace('<br />' . PHP_EOL, PHP_EOL, $html);
-            $html = str_replace('<br />', PHP_EOL, $html);
-
-            $html = \decodeHTML(trim($html));
-        }
-
-        return $html;
-    }
-}
-
-/**
- * Members of Studip\MarkupPrivate must not be used outside of this file!!
- */
-
-namespace Studip\MarkupPrivate\Purifier;
-
-use Studip\MarkupPrivate\MediaProxy;
-
-/**
- * Remove invalid <img src> attributes.
- */
-class AttrTransform_Image_Source extends \HTMLPurifier_AttrTransform
-{
-    /**
-     * Implements abstract method of base class.
-     */
-    function transform($attr, $config, $context)
-    {
-        try {
-            $attr['src'] = MediaProxy\getMediaUrl($attr['src']);
-        } catch (MediaProxy\InvalidInternalLinkException $e) {
-            // invalid internal link ==> remove <img src> attribute
-            $GLOBALS['msg'][] = _('Ungültige interne Medienverknüpfung entfernt: ')
-                . \htmlentities($e->getUrl());
-            $attr['src'] = NULL; // remove <img src> attribute
-        } catch (MediaProxy\ExternalMediaDeniedException $e) {
-            $GLOBALS['msg'][] = _('Verbotene externe Medienverknüpfung entfernt: ')
-                . \htmlentities($e->getUrl());
-            $attr['src'] = NULL; // remove <img src> attribute
-        }
-        return $attr;
-    }
-}
-
-//// media proxy //////////////////////////////////////////////////////////////
-
-namespace Studip\MarkupPrivate\MediaProxy;
-
-use Studip\MarkupPrivate\Text;
-
-/**
- * Check if media proxy should be used and if so return the respective URL.
- *
- * @param string $url   URL to media file.
- * @return mixed        URL string to media file (possibly 'proxied')
- *                      or NULL if URL is invalid.
- */
-function getMediaUrl($url) {
-    // even though proxied URLs shouldn't be stored in the database, the
-    // next line will handle those cases where they're accidentally there
-    $url = decodeMediaProxyUrl($url);
-
-    // handle internal media links
-    if (isStudipMediaUrl($url)) {
-        return transformInternalIdnaLink($url);
-    }
-    if (isInternalLink($url)) {
-        // link is studip-internal, but not to a valid media location
-        throw new InvalidInternalLinkException($url);
-    }
-
-    // handle external media links
-    $external_media = \Config::get()->LOAD_EXTERNAL_MEDIA;
-    if ($external_media === 'proxy' &&
-        \Seminar_Session::is_current_session_authenticated()
-    ) {
-        // media proxy must be accessed by an internal link
-        return encodeMediaProxyUrl($url);
-    }
-    if ($external_media === 'allow') {
-        return $url;
-    }
-    throw new ExternalMediaDeniedException($url);
-}
-
-/**
- * Return media proxy URL for an unproxied URL.
- *
- * @params string $url  Unproxied media URL.
- * @return string       Media proxy URL for accessing the same resource.
- */
-function encodeMediaProxyUrl($url) {
-    return transformInternalIdnaLink(
-        getMediaProxyUrl() .'?url=' . \urlencode(\idna_link($url)));
-}
-
-/**
- * Extract the original URL from a media proxy URL.
- *
- * @param string  $url  The media proxy URL.
- * return string  The original URL. If $url does not point to the media
- *                proxy then this is the exact same value given by $url.
- */
-function decodeMediaProxyUrl($url) {
-    # TODO make it work for 'url=' at any position in query
-    $urlpath = removeStudipDomain($url);
-    $proxypath = removeStudipDomain(getMediaProxyUrl()) . '?url=';
-    if (Text\startsWith($urlpath, $proxypath)) {
-        return \urldecode(Text\removePrefix($urlpath, $proxypath));
-    }
-    return $url;
-}
-
-/**
- * Return Stud.IP's absolute media proxy URL.
- */
-function getMediaProxyUrl() {
-    return $GLOBALS['ABSOLUTE_URI_STUDIP'] . 'dispatch.php/media_proxy';
-}
-
-/**
- * Test if an URL points to a valid internal Stud.IP media path.
- *
- * @param   string   $url  Internal Stud.IP URL.
- * @returns boolean  TRUE for internal media link URLs, FALSE otherwise.
- */
-function isStudipMediaUrl($url) {
-    return isInternalLink($url) &&
-        isStudipMediaUrlPath(getStudipRelativePath($url));
-}
-
-function isInternalLink($url) {
-    return is_internal_url(transformInternalIdnaLink($url));
-}
-
-//// url utilities ////////////////////////////////////////////////////////////
-
-/**
- * Remove domain name from internal URLs.
- *
- * Remove scheme, domain and authentication information from internal
- * Stud.IP URLs. Leave external URLs untouched.
- *
- * @param string $url   URL from which to remove internal domain.
- * @returns string      URL without internal domain or the exact same
- *                      value as $url for external URLs.
- */
-function removeStudipDomain($url) {
-    if (!isInternalLink($url)) {
-        return $url;
-    }
-    $parsed_url = \parse_url(transformInternalIdnaLink($url));
-    $path = isset($parsed_url['path']) ? $parsed_url['path'] : '';
-    $query = isset($parsed_url['query']) ? '?' . $parsed_url['query'] : '';
-    $fragment = isset($parsed_url['fragment']) ? '#' . $parsed_url['fragment'] : '';
-    return $path . $query . $fragment;
-}
-
-/**
- * Return a URL's path component with the absolute Stud.IP path removed.
- *
- * NOTE: If the URL is not an internal Stud.IP URL, the path component will
- * nevertheless be returned without issuing an error message.
- *
- * Example:
- * >>> getStudipRelativePath('http://localhost:8080'
- *      . '/studip/sendfile.php?type=0&file_id=ABC123&file_name=nice.jpg')
- * 'sendfile.php'
- *
- * @param string $url   The URL from which to return the Stud.IP-relative
- *                      path component.
- * returns string Stud.IP-relative path component of $url.
- */
-function getStudipRelativePath($url) {
-    $parsed_url = \parse_url(transformInternalIdnaLink($url));
-    $parsed_studip_url = getParsedStudipUrl();
-    return Text\removePrefix($parsed_url['path'], $parsed_studip_url['path']);
-}
-
-/**
- * Return an associative array containing the Stud.IP URL elements.
- *
- * see also: http://php.net/manual/en/function.parse-url.php
- *
- * @returns mixed  Same values that PHP's parse_url() returns.
- */
-function getParsedStudipUrl() {
-    return \parse_url($GLOBALS['ABSOLUTE_URI_STUDIP']);
-}
-
-/**
- * Test if path is valid for internal Stud.IP media URLs.
- *
- * @params string $path The path component of an URL.
- * return boolean       TRUE for valid media paths, FALSE otherwise.
- */
-function isStudipMediaUrlPath($path) {
-    list($path_head) = \explode('/', $path);
-    $valid_paths = ['sendfile.php', 'download', 'assets', 'pictures'];
-    return \mb_strpos(\urldecode($path), '../') === false && \in_array($path_head, $valid_paths);
-}
-
-/**
- * Return a normalized, internal URL.
- *
- * @params string $url  An internal URL.
- * @returns string      Normalized internal URL.
- */
-function transformInternalIdnaLink($url) {
-    return \idna_link(\TransformInternalLinks($url));
-}
-
-//// url exceptions ///////////////////////////////////////////////////////////
-
-class UrlException extends \Exception
-{
-    private $url;
-
-    public function __construct($url) {
-        parent::__construct();
-        $this->url = $url;
-    }
-
-    public function getUrl()
-    {
-        return $this->url;
-    }
-}
-
-class InvalidInternalLinkException extends UrlException
-{
-}
-
-class ExternalMediaDeniedException extends UrlException
-{
-}
-
-//// string utilities /////////////////////////////////////////////////////////
-
-namespace Studip\MarkupPrivate\Text;
-
-/**
- * Test if string starts with prefix.
- *
- * @param string $string  Tested string.
- * @param string $prefix  Prefix of tested string.
- *
- * @return boolean  TRUE if string starts with prefix.
- */
-function startsWith($string, $prefix) {
-    return \mb_substr($string, 0, \mb_strlen($prefix)) === $prefix;
-}
-
-/**
- * Test if string ends with suffix.
- *
- * @param string $string  Tested string.
- * @param string $suffix  Suffix of tested string.
- *
- * @return boolean  TRUE if string ends with suffix.
- */
-function endsWith($string, $suffix) {
-    return \mb_substr($string, - \mb_strlen($suffix)) === $suffix;
-}
-
-/**
- * Remove prefix from string.
- *
- * Does not change the string if it has a different prefix.
- *
- * @param string $string The string that must start with the prefix.
- * @param string $prefix The prefix of the string.
- *
- * @return string String without prefix.
- */
-function removePrefix($string, $prefix) {
-    return startsWith($string, $prefix) ? \mb_substr($string, \mb_strlen($prefix)) : $string;
-}