Pin QtDBus shared library on Windows after being loaded by X-Plane

refs #850

src/blackmisc/dbus.cpp

@@ -0,0 +1,34 @@
+/* Copyright (C) 2016
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
+ * including this file, may be copied, modified, propagated, or distributed except according to the terms
+ * contained in the LICENSE file.
+ */
+
+#include "dbus.h"
+
+#ifdef Q_OS_WIN
+#include <QDBusConnection>
+#include <qt_windows.h>
+
+// https://blogs.msdn.microsoft.com/oldnewthing/20131105-00/?p=2733
+// See https://bugreports.qt.io/browse/QTBUG-53031 for more details
+// why this is necessary.
+void preventQtDBusDllUnload()
+{
+    // Only Qt 5.8.0 is affected.
+    if (qVersion() != QByteArray("5.8.0")) { return; }
+
+    static HMODULE dbusDll;
+    GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
+                      GET_MODULE_HANDLE_EX_FLAG_PIN,
+                      reinterpret_cast<LPCTSTR >(&QDBusConnection::staticMetaObject),
+                      &dbusDll);
+    Q_ASSERT(dbusDll);
+}
+#else
+void preventQtDBusDllUnload()
+{ }
+#endif