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htmlutils.cpp
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htmlutils.cpp
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// SPDX-FileCopyrightText: 2017 Christian Mollekopf <mollekopf@kolabsys.com>
// SPDX-License-Identifier: LGPL-2.0-or-later
#include "htmlutils.h"
#include <QMap>
#include <QUrl>
static QString resolveEntities(const QString &in)
{
QString out;
for (int i = 0; i < (int)in.length(); ++i) {
if (in[i] == QLatin1Char('&')) {
// find a semicolon
++i;
int n = in.indexOf(QLatin1Char(';'), i);
if (n == -1) {
break;
}
QString type = in.mid(i, (n - i));
i = n; // should be n+1, but we'll let the loop increment do it
if (type == QLatin1StringView("amp")) {
out += QLatin1Char('&');
} else if (type == QLatin1StringView("lt"))
out += QLatin1Char('<');
else if (type == QLatin1StringView("gt"))
out += QLatin1Char('>');
else if (type == QLatin1StringView("quot"))
out += QLatin1Char('\"');
else if (type == QLatin1StringView("apos"))
out += QLatin1Char('\'');
else if (type == QLatin1StringView("nbsp"))
out += QChar(0xa0);
} else {
out += in[i];
}
}
return out;
}
static bool linkify_pmatch(const QString &str1, int at, const QString &str2)
{
if (str2.length() > (str1.length() - at))
return false;
for (int n = 0; n < (int)str2.length(); ++n) {
if (str1.at(n + at).toLower() != str2.at(n).toLower())
return false;
}
return true;
}
static bool linkify_isOneOf(const QChar &c, const QString &charlist)
{
for (int i = 0; i < (int)charlist.length(); ++i) {
if (c == charlist.at(i))
return true;
}
return false;
}
// encodes a few dangerous html characters
static QString linkify_htmlsafe(const QString &in)
{
QString out;
for (int n = 0; n < in.length(); ++n) {
if (linkify_isOneOf(in.at(n), QStringLiteral("\"\'`<>"))) {
// hex encode
QString hex;
hex.asprintf("%%%02X", in.at(n).toLatin1());
out.append(hex);
} else {
out.append(in.at(n));
}
}
return out;
}
static bool linkify_okUrl(const QString &url)
{
if (url.at(url.length() - 1) == QLatin1Char('.'))
return false;
return true;
}
static bool linkify_okEmail(const QString &addy)
{
// this makes sure that there is an '@' and a '.' after it, and that there is
// at least one char for each of the three sections
int n = addy.indexOf(QLatin1Char('@'));
if (n == -1 || n == 0)
return false;
int d = addy.indexOf(QLatin1Char('.'), n + 1);
if (d == -1 || d == 0)
return false;
if ((addy.length() - 1) - d <= 0)
return false;
if (addy.indexOf(QStringLiteral("..")) != -1)
return false;
return true;
}
/**
* takes a richtext string and heuristically adds links for uris of common protocols
* @return a richtext string with link markup added
*/
QString MimeTreeParser::linkify(const QString &in)
{
QString out = in;
int x1, x2;
QString linked, link, href;
for (int n = 0; n < (int)out.length(); ++n) {
bool isUrl = false;
bool isAtStyle = false;
x1 = n;
if (linkify_pmatch(out, n, QStringLiteral("xmpp:"))) {
n += 5;
isUrl = true;
href = QString();
} else if (linkify_pmatch(out, n, QStringLiteral("mailto:"))) {
n += 7;
isUrl = true;
href = QString();
} else if (linkify_pmatch(out, n, QStringLiteral("http://"))) {
n += 7;
isUrl = true;
href = QString();
} else if (linkify_pmatch(out, n, QStringLiteral("https://"))) {
n += 8;
isUrl = true;
href = QString();
} else if (linkify_pmatch(out, n, QStringLiteral("ftp://"))) {
n += 6;
isUrl = true;
href = QString();
} else if (linkify_pmatch(out, n, QStringLiteral("news://"))) {
n += 7;
isUrl = true;
href = QString();
} else if (linkify_pmatch(out, n, QStringLiteral("ed2k://"))) {
n += 7;
isUrl = true;
href = QString();
} else if (linkify_pmatch(out, n, QStringLiteral("magnet:"))) {
n += 7;
isUrl = true;
href = QString();
} else if (linkify_pmatch(out, n, QStringLiteral("www."))) {
isUrl = true;
href = QStringLiteral("http://");
} else if (linkify_pmatch(out, n, QStringLiteral("ftp."))) {
isUrl = true;
href = QStringLiteral("ftp://");
} else if (linkify_pmatch(out, n, QStringLiteral("@"))) {
isAtStyle = true;
href = QStringLiteral("x-psi-atstyle:");
}
if (isUrl) {
// make sure the previous char is not alphanumeric
if (x1 > 0 && out.at(x1 - 1).isLetterOrNumber())
continue;
// find whitespace (or end)
QMap<QChar, int> brackets;
brackets[QLatin1Char('(')] = brackets[QLatin1Char(')')] = brackets[QLatin1Char('[')] = brackets[QLatin1Char(']')] = brackets[QLatin1Char('{')] =
brackets[QLatin1Char('}')] = 0;
QMap<QChar, QChar> openingBracket;
openingBracket[QLatin1Char(')')] = QLatin1Char('(');
openingBracket[QLatin1Char(']')] = QLatin1Char('[');
openingBracket[QLatin1Char('}')] = QLatin1Char('{');
for (x2 = n; x2 < (int)out.length(); ++x2) {
if (out.at(x2).isSpace() || linkify_isOneOf(out.at(x2), QStringLiteral("\"\'`<>")) || linkify_pmatch(out, x2, QStringLiteral("&quot;"))
|| linkify_pmatch(out, x2, QStringLiteral("&apos;")) || linkify_pmatch(out, x2, QStringLiteral("&gt;"))
|| linkify_pmatch(out, x2, QStringLiteral("&lt;"))) {
break;
}
if (brackets.contains(out.at(x2))) {
++brackets[out.at(x2)];
}
}
int len = x2 - x1;
QString pre = resolveEntities(out.mid(x1, x2 - x1));
// go backward hacking off unwanted punctuation
int cutoff;
for (cutoff = pre.length() - 1; cutoff >= 0; --cutoff) {
if (!linkify_isOneOf(pre.at(cutoff), QStringLiteral("!?,.()[]{}<>\"")))
break;
if (linkify_isOneOf(pre.at(cutoff), QStringLiteral(")]}")) && brackets[pre.at(cutoff)] - brackets[openingBracket[pre.at(cutoff)]] <= 0) {
break; // in theory, there could be == above, but these are urls, not math ;)
}
if (brackets.contains(pre.at(cutoff))) {
--brackets[pre.at(cutoff)];
}
}
++cutoff;
//++x2;
link = pre.mid(0, cutoff);
if (!linkify_okUrl(link)) {
n = x1 + link.length();
continue;
}
href += link;
// attributes need to be encoded too.
href = href.toHtmlEscaped();
href = linkify_htmlsafe(href);
// printf("link: [%s], href=[%s]\n", link.latin1(), href.latin1());
linked = QStringLiteral("<a href=\"%1\">").arg(href) + QUrl{link}.toDisplayString(QUrl::RemoveQuery) + QStringLiteral("</a>")
+ pre.mid(cutoff).toHtmlEscaped();
out.replace(x1, len, linked);
n = x1 + linked.length() - 1;
} else if (isAtStyle) {
// go backward till we find the beginning
if (x1 == 0)
continue;
--x1;
for (; x1 >= 0; --x1) {
if (!linkify_isOneOf(out.at(x1), QStringLiteral("_.-+")) && !out.at(x1).isLetterOrNumber())
break;
}
++x1;
// go forward till we find the end
x2 = n + 1;
for (; x2 < (int)out.length(); ++x2) {
if (!linkify_isOneOf(out.at(x2), QStringLiteral("_.-+")) && !out.at(x2).isLetterOrNumber())
break;
}
int len = x2 - x1;
link = out.mid(x1, len);
// link = resolveEntities(link);
if (!linkify_okEmail(link)) {
n = x1 + link.length();
continue;
}
href += link;
// printf("link: [%s], href=[%s]\n", link.latin1(), href.latin1());
linked = QStringLiteral("<a href=\"%1\">").arg(href) + link + QStringLiteral("</a>");
out.replace(x1, len, linked);
n = x1 + linked.length() - 1;
}
}
return out;
}

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text/x-c
Expires
Thu, Mar 19, 6:07 PM (20 h, 17 m)
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