CLI: Fix XML encoding when export database

Add write function to TextStream
Fix keepassxreboot#3900

src/cli/Export.cpp

@@ -51,7 +51,7 @@ int Export::executeWithDatabase(QSharedPointer<Database> database, QSharedPointe
             errorTextStream << QObject::tr("Unable to export database to XML: %1").arg(errorMessage) << endl;
             return EXIT_FAILURE;
         }
-        outputTextStream << xmlData.constData() << endl;
+        outputTextStream.write(xmlData.constData());
     } else if (format.startsWith(QStringLiteral("csv"), Qt::CaseInsensitive)) {
         CsvExporter csvExporter;
         outputTextStream << csvExporter.exportDatabase(database);

src/cli/TextStream.cpp

@@ -58,6 +58,15 @@ TextStream::TextStream(const QByteArray& array, QIODevice::OpenMode openMode)
     detectCodec();
 }
 
+void TextStream::write(const char* str)
+{
+    // Workaround for an issue with QTextStream. Its operator<<(const char *string) will encode the
+    // string with a non-UTF-8 encoding. We work around this by wrapping the input string into
+    // a QString, thus enforcing UTF-8. More info:
+    // https://code.qt.io/cgit/qt/qtbase.git/commit?id=cec8cdba4d1b856e17c8743ba8803349d42dc701
+    *this << QString(str);
+}
+
 void TextStream::detectCodec()
 {
     QString codecName = "UTF-8";

src/cli/TextStream.h

@@ -43,6 +43,8 @@ class TextStream : public QTextStream
     explicit TextStream(QByteArray* array, QIODevice::OpenMode openMode = QIODevice::ReadWrite);
     explicit TextStream(const QByteArray& array, QIODevice::OpenMode openMode = QIODevice::ReadOnly);
 
+    void write(const char* str);
+
 private:
     void detectCodec();
 };