Merge remote-tracking branch 'origin/5.13' into 5.14v5.14.0-beta1

Change-Id: Ie236fa47c23456b15414c3b3e89568b915979ebe

2 files changed, 15 insertions, 2 deletions

diff --git a/src/client/qwaylandwindow.cpp b/src/client/qwaylandwindow.cpp
index ccf4f8dac..2704705e7 100644
--- a/src/client/qwaylandwindow.cpp
+++ b/src/client/qwaylandwindow.cpp
@@ -303,8 +303,10 @@ void QWaylandWindow::setWindowTitle(const QString &title)
         const QString formatted = formatWindowTitle(title, separator);
 
         const int libwaylandMaxBufferSize = 4096;
-        // Some parts of the buffer is used for metadata, so subtract 100 to be on the safe side
-        const int maxLength = libwaylandMaxBufferSize - 100;
+        // Some parts of the buffer is used for metadata, so subtract 100 to be on the safe side.
+        // Also, QString is in utf-16, which means that in the worst case each character will be
+        // three bytes when converted to utf-8 (which is what libwayland uses), so divide by three.
+        const int maxLength = libwaylandMaxBufferSize / 3 - 100;
 
         auto truncated = QStringRef(&formatted).left(maxLength);
         if (truncated.length() < formatted.length()) {
diff --git a/tests/auto/client/client/tst_client.cpp b/tests/auto/client/client/tst_client.cpp
index e9ae5e4b3..e19acff7c 100644
--- a/tests/auto/client/client/tst_client.cpp
+++ b/tests/auto/client/client/tst_client.cpp
@@ -184,6 +184,7 @@ private slots:
     void glWindow();
 #endif // QT_CONFIG(opengl)
     void longWindowTitle();
+    void longWindowTitleWithUtf16Characters();
 
 private:
     MockCompositor *compositor = nullptr;
@@ -502,6 +503,16 @@ void tst_WaylandClient::longWindowTitle()
     QTRY_VERIFY(compositor->surface());
 }
 
+void tst_WaylandClient::longWindowTitleWithUtf16Characters()
+{
+    QWindow window;
+    QString absurdlyLongTitle = QString("三").repeated(10000);
+    Q_ASSERT(absurdlyLongTitle.length() == 10000); // just making sure the test isn't broken
+    window.setTitle(absurdlyLongTitle);
+    window.show();
+    QTRY_VERIFY(compositor->surface());
+}
+
 int main(int argc, char **argv)
 {
     setenv("XDG_RUNTIME_DIR", ".", 1);