File indexing completed on 2024-05-12 03:47:46

 /*
     File                 : PropertyChangeCommand.h
     Project              : SciDAVis / LabPlot
     Description          : Generic undo command changing a single variable.
     --------------------------------------------------------------------
     SPDX-FileCopyrightText: 2010 Knut Franke <Knut.Franke*gmx.net (use @ for *)>
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #ifndef PROPERTY_CHANGE_COMMAND_H
 #define PROPERTY_CHANGE_COMMAND_H
 
 #include <QUndoCommand>
 
 /**
  * \class PropertyChangeCommand
  * \brief Generic undo command changing a single variable.
  *
  * Given a pointer to a variable (usually a member of the class instantiating the command, or of
  * its private implementation class) and a new value, assigns the value to the variable. A backup
  * of the old value is made, so that undo/redo can switch back and forth between the two values.
  * The value type needs to support copy construction and assignment.
  */
 
 template<class T>
 class PropertyChangeCommand : public QUndoCommand {
 public:
     PropertyChangeCommand(const QString& text, T* property, const T& new_value)
         : m_property(property)
         , m_other_value(new_value) {
         setText(text);
     }
 
     void redo() override {
         T tmp = *m_property;
         *m_property = m_other_value;
         m_other_value = tmp;
     }
 
     void undo() override {
         redo();
     }
 
     int id() const override {
         return reinterpret_cast<std::intptr_t>(m_property);
     }
 
     bool mergeWith(const QUndoCommand* other) override {
         if (other->id() != id())
             return false;
 
         if (std::is_same<T, bool>::value)
             *m_property = *(static_cast<const PropertyChangeCommand*>(other)->m_property);
         else
             *m_property += *(static_cast<const PropertyChangeCommand*>(other)->m_property);
 
         return true;
     }
 
     T* m_property;
 
 private:
     T m_other_value;
 };
 
 #endif // ifndef PROPERTY_CHANGE_COMMAND_H