diff --git a/src/levelloader.h b/src/levelloader.h
index e19d4d9..fb10d6a 100644
--- a/src/levelloader.h
+++ b/src/levelloader.h
@@ -1,89 +1,89 @@
 /*
     Copyright 20011 Julian Helfferich <julian.helfferich@gmail.com>
 
     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.
 
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #ifndef LEVELLOADER_H
 #define LEVELLOADER_H
 
 #include <QObject>
 
 class QDomDocument;
 class QDomElement;
 
 class LevelLoader : public QObject
 {
     Q_OBJECT
 public:
     explicit LevelLoader(QObject *parent = nullptr);
     ~LevelLoader();
 
     int level() const;
     void setLevel(int level);
     QString levelset() const;
     void setLevelset(const QString &levelname);
 
     void loadLevel();
 
 Q_SIGNALS:
-    void newLine(QString line, int lineNumber);
-    void newGift(QString giftType, int times, QString position);
+    void newLine(const QString &line, int lineNumber);
+    void newGift(const QString &giftType, int times, const QString &position);
 
 private:
     void loadLine(QDomElement lineNode);
     void loadGift(QDomElement giftNode);
 
     void loadOldStyleLevel();
 
     QDomDocument *m_levelset;
     bool m_oldstyle;
 
     int m_lineNumber;
     QString m_levelname;
     int m_level;
 };
 
 // Global list of gift types
 // Can be removed, when KConfig levelsets are no longer supported
 
 const QString GIFT_TYPES[] = {
     QStringLiteral("Gift100Points"),
     QStringLiteral("Gift200Points"),
     QStringLiteral("Gift500Points"),
     QStringLiteral("Gift1000Points"),
     QStringLiteral("GiftAddLife"),
 
     QStringLiteral("GiftLoseLife"),
     QStringLiteral("GiftNextLevel"),
     QStringLiteral("GiftSplitBall"),
     QStringLiteral("GiftAddBall"),
     QStringLiteral("GiftDecreaseSpeed"),
 
     QStringLiteral("GiftIncreaseSpeed"),
     QStringLiteral("GiftUnstoppableBall"),
     QStringLiteral("GiftBurningBall"),
     QStringLiteral("GiftMagicWand"),
     QStringLiteral("GiftMagicEye"),
 
     QStringLiteral("GiftEnlargeBar"),
     QStringLiteral("GiftShrinkBar"),
     QStringLiteral("GiftStickyBar"),
     QStringLiteral("GiftMoreExplosion")
 };
 
 // IMPORTANT: keep in sync with the above
 const int GIFT_TYPES_COUNT = 19;
 
 #endif // LEVELLOADER_H