Replace AddItemCommand class by AddGraphicsObjectCommand

The class is the same except the name and the use of QPointer to avoid
segfault with deleted QGraphicsObject.

sources/undocommand/addgraphicsobjectcommand.h

@@ -0,0 +1,52 @@
+/*
+        Copyright 2006-2021 The QElectroTech Team
+        This file is part of QElectroTech.
+
+        QElectroTech is free software: you can redistribute it and/or modify
+        it under the terms of the GNU General Public License as published by
+        the Free Software Foundation, either version 2 of the License, or
+        (at your option) any later version.
+
+        QElectroTech is distributed in the hope that it will be useful,
+        but WITHOUT ANY WARRANTY; without even the implied warranty of
+        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+        GNU General Public License for more details.
+
+        You should have received a copy of the GNU General Public License
+        along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#ifndef ADDGRAPHICSOBJECTCOMMAND_H
+#define ADDGRAPHICSOBJECTCOMMAND_H
+
+#include <QUndoCommand>
+#include <QPointF>
+#include <QPointer>
+
+class QGraphicsObject;
+class Diagram;
+
+/**
+ * @brief The AddGraphicsObjectCommand class
+ * Undo command to used to add item to a diagram.
+ */
+class AddGraphicsObjectCommand : public QUndoCommand
+{
+   public:
+        AddGraphicsObjectCommand(QGraphicsObject *qgo, Diagram *diagram,
+                                 const QPointF &pos = QPointF(),
+                                 QUndoCommand *parent = nullptr);
+        ~AddGraphicsObjectCommand() override;
+
+        void undo() override;
+        void redo() override;
+
+    private:
+        QString itemText() const;
+
+    private:
+        QPointer<QGraphicsObject> m_item;
+        Diagram *m_diagram = nullptr;
+        QPointF m_pos;
+};
+
+#endif // ADDGRAPHICSOBJECTCOMMAND_H