Connection guard (detected during #477)

Disconnects Qt signal/slot conenction when destroyed

src/blackmisc/connectionguard.h

@@ -0,0 +1,54 @@
+/* Copyright (C) 2015
+ * 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.
+ */
+
+//! \file
+
+#ifndef BLACKMISC_CONNECTIONGUARD_H
+#define BLACKMISC_CONNECTIONGUARD_H
+
+#include "blackmisc/blackmiscexport.h"
+#include <QList>
+#include <QObject>
+
+namespace BlackMisc
+{
+    /*!
+     * List of QMetaObject::Connection. The trick here is that those connections will
+     * be disconnected when the object is destroyed. So it can be used with lambdas or bind which feature
+     * non QObjects, if those might be destroyed before the signaling QObject.
+     */
+    class BLACKMISC_EXPORT CConnectionGuard : public QObject
+    {
+        Q_OBJECT
+
+    public:
+        //! Constructor
+        CConnectionGuard() = default;
+
+        //! Constructor
+        CConnectionGuard(const QMetaObject::Connection &connection);
+
+        //! Destructor
+        ~CConnectionGuard();
+
+        //! Add connection
+        void append(const QMetaObject::Connection &connection);
+
+        //! Add connections
+        void append(const QList<QMetaObject::Connection> &connections);
+
+        //! Disconnect all
+        int disconnectAll();
+
+    private:
+        QList<QMetaObject::Connection> m_connections;
+    };
+} // BlackMisc
+
+#endif