wayland: Truncate virtual desktop names

Virtual desktop names are user defined strings so they can exceed
the maximum size of a wayland message size.

BUG: 480614

src/wayland/CMakeLists.txt

@@ -359,6 +359,7 @@ install(FILES
     primaryselectiondevicemanager_v1.h
     primaryselectionoffer_v1.h
     primaryselectionsource_v1.h
+    quirks.h
     relativepointer_v1.h
     screencast_v1.h
     screenedge_v1.h

src/wayland/plasmavirtualdesktop.cpp

@@ -5,6 +5,7 @@
 */
 #include "plasmavirtualdesktop.h"
 #include "display.h"
+#include "wayland/quirks.h"
 
 #include <QDebug>
 #include <QTimer>
@@ -240,7 +241,7 @@ void PlasmaVirtualDesktopInterfacePrivate::org_kde_plasma_virtual_desktop_bind_r
     send_desktop_id(resource->handle, id);
 
     if (!name.isEmpty()) {
-        send_name(resource->handle, name);
+        send_name(resource->handle, truncate(name));
     }
 
     if (active) {
@@ -272,7 +273,7 @@ void PlasmaVirtualDesktopInterface::setName(const QString &name)
 
     const auto clientResources = d->resourceMap();
     for (auto resource : clientResources) {
-        d->send_name(resource->handle, name);
+        d->send_name(resource->handle, truncate(name));
     }
 }
 

src/wayland/plasmawindowmanagement.cpp

@@ -9,6 +9,7 @@
 #include "plasmavirtualdesktop.h"
 #include "surface.h"
 #include "utils/common.h"
+#include "wayland/quirks.h"
 
 #include <QFile>
 #include <QHash>
@@ -26,19 +27,6 @@ namespace KWin
 static const quint32 s_version = 16;
 static const quint32 s_activationVersion = 1;
 
-// any strings that come from user-defined sources
-// that could exceed the maximum wayland length (i.e xwayland clients)
-// need to be truncated to the maximumWaylandBufferSize
-static QString truncate(const QString &stringIn)
-{
-    const int libwaylandMaxBufferSize = 4096;
-    // 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;
-    return stringIn.left(maxLength);
-}
-
 class PlasmaWindowManagementInterfacePrivate : public QtWaylandServer::org_kde_plasma_window_management
 {
 public:

src/wayland/quirks.h

@@ -0,0 +1,27 @@
+/*
+    SPDX-FileCopyrightText: 2024 David Edmundson <kde@davidedmundson.co.uk>
+
+    SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+#pragma once
+
+#include <QString>
+
+namespace KWin
+{
+
+/**
+ * Any strings that come from user-defined sources that could exceed the maximum wayland length (e.g. xwayland clients)
+ * need to be truncated to the maximumWaylandBufferSize.
+ */
+static inline QString truncate(const QString &stringIn)
+{
+    const int libwaylandMaxBufferSize = 4096;
+    // 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;
+    return stringIn.left(maxLength);
+}
+
+} // namespace KWin