replaced link regex with object oriented assembly

src/common/LinkParser.cpp

@@ -1,30 +1,204 @@
 #include "common/LinkParser.hpp"
 
 #include <QFile>
+#include <QMap>
 #include <QRegularExpression>
 #include <QString>
+#include <QStringRef>
 #include <QTextStream>
 
 namespace chatterino {
+namespace {
+    QSet<QString> &tlds()
+    {
+        static QSet<QString> tlds = [] {
+            QFile file(":/tlds.txt");
+            file.open(QFile::ReadOnly);
+            QTextStream stream(&file);
+            stream.setCodec("UTF-8");
+            int safetyMax = 20000;
+
+            QSet<QString> set;
+
+            while (!stream.atEnd())
+            {
+                auto line = stream.readLine();
+                set.insert(line);
+
+                if (safetyMax-- == 0)
+                    break;
+            }
+
+            return set;
+        }();
+        return tlds;
+    }
+
+    bool isValidHostname(QStringRef &host)
+    {
+        int index = host.lastIndexOf('.');
+
+        return index != -1 &&
+               tlds().contains(host.mid(index + 1).toString().toLower());
+    }
+
+    bool isValidIpv4(QStringRef &host)
+    {
+        static auto exp = QRegularExpression("^\\d{1,3}(?:\\.\\d{1,3}){3}$");
+
+        return exp.match(host).hasMatch();
+    }
+
+#ifdef C_MATCH_IPV6_LINK
+    bool isValidIpv6(QStringRef &host)
+    {
+        static auto exp = QRegularExpression("^\\[[a-f0-9:%]+\\]$");
+
+        return exp.match(host).hasMatch();
+    }
+#endif
+}  // namespace
 
 LinkParser::LinkParser(const QString &unparsedString)
 {
-    static QRegularExpression linkRegex(
+    this->match_ = unparsedString;
-        "^(?:http(s)?:\\/\\/)?[\\w.-]+(?:\\.[\\w\\.-]+)+[\\w\\-\\._~:/"
-        "?#[\\]@!\\$&'\\(\\)\\*\\+,;=.]+$",
-        QRegularExpression::CaseInsensitiveOption);
 
-    this->match_ = linkRegex.match(unparsedString);
+    // This is not implemented with a regex to increase performance.
+    // We keep removing parts of the url until there's either nothing left or we fail.
+    QStringRef l(&unparsedString);
+
+    bool hasHttp = false;
+
+    // Protocol `https?://`
+    if (l.startsWith("https://"))
+    {
+        hasHttp = true;
+        l = l.mid(8);
+    }
+    else if (l.startsWith("http://"))
+    {
+        hasHttp = true;
+        l = l.mid(7);
+    }
+
+    // Http basic auth `user:password`.
+    // Not supported for security reasons (misleading links)
+
+    // Host `a.b.c.com`
+    QStringRef host = l;
+    bool lastWasDot = true;
+    bool inIpv6 = false;
+
+    for (int i = 0; i < l.size(); i++)
+    {
+        if (l[i] == '.')
+        {
+            if (lastWasDot == true)  // no double dots ..
+                goto error;
+            lastWasDot = true;
+        }
+        else
+        {
+            lastWasDot = false;
+        }
+
+        if (l[i] == ':' && !inIpv6)
+        {
+            host = l.mid(0, i);
+            l = l.mid(i + 1);
+            goto parsePort;
+        }
+        else if (l[i] == '/')
+        {
+            host = l.mid(0, i);
+            l = l.mid(i + 1);
+            goto parsePath;
+        }
+        else if (l[i] == '?')
+        {
+            host = l.mid(0, i);
+            l = l.mid(i + 1);
+            goto parseQuery;
+        }
+        else if (l[i] == '#')
+        {
+            host = l.mid(0, i);
+            l = l.mid(i + 1);
+            goto parseAnchor;
+        }
+
+        // ipv6
+        if (l[i] == '[')
+        {
+            if (i == 0)
+                inIpv6 = true;
+            else
+                goto error;
+        }
+        else if (l[i] == ']')
+        {
+            inIpv6 = false;
+        }
+    }
+
+    if (lastWasDot)
+        goto error;
+    else
+        goto done;
+
+parsePort:
+    // Port `:12345`
+    for (int i = 0; i < std::min<int>(5, l.size()); i++)
+    {
+        if (l[i] == '/')
+            goto parsePath;
+        else if (l[i] == '?')
+            goto parseQuery;
+        else if (l[i] == '#')
+            goto parseAnchor;
+
+        if (!l[i].isDigit())
+            goto error;
+    }
+
+    goto done;
+
+parsePath:
+parseQuery:
+parseAnchor:
+    // we accept everything in the path/query/anchor
+
+done:
+    // check host
+    if (this->hasMatch_)
+    {
+        this->hasMatch_ = isValidHostname(host) || isValidIpv4(host)
+#ifdef C_MATCH_IPV6_LINK
+
+                          || (hasHttp && isValidIpv6(host))
+#endif
+            ;
+
+        if (this->hasMatch_)
+        {
+            this->match_ = unparsedString;
+        }
+    }
+
+    return;
+
+error:
+    hasMatch_ = false;
 }
 
 bool LinkParser::hasMatch() const
 {
-    return this->match_.hasMatch();
+    return this->hasMatch_;
 }
 
 QString LinkParser::getCaptured() const
 {
-    return this->match_.captured();
+    return this->match_;
 }
 
 }  // namespace chatterino

src/common/LinkParser.hpp

@@ -14,7 +14,8 @@ public:
     QString getCaptured() const;
 
 private:
-    QRegularExpressionMatch match_;
+    bool hasMatch_;
+    QString match_;
 };
 
 }  // namespace chatterino