Add UndoCommand class

Add a class to handle all undo/redo events. Whenever a user
action affects a dive, an undo command will be created. A list of
these commands will be stored in the UndoBuffer, to allow for
moving forwards/backwards in the list.

Signed-off-by: Grace Karanja <gracie.karanja89@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/undobuffer.cpp

@@ -39,3 +39,21 @@ void UndoBuffer::recordAfter(dive *affectedDive)
 {
 
 }
+
+
+
+UndoCommand::UndoCommand(QString commandName, dive *affectedDive)
+{
+	name = commandName;
+	stateBefore = affectedDive;
+}
+
+void UndoCommand::undo()
+{
+
+}
+
+void UndoCommand::redo()
+{
+
+}

qt-ui/undobuffer.h

@@ -4,6 +4,19 @@
 #include <QObject>
 #include "dive.h"
 
+class UndoCommand {
+private:
+	dive* stateBefore;
+	dive* stateAfter;
+	QString name;
+
+public:
+	explicit UndoCommand(QString commandName, dive* affectedDive);
+	void setStateAfter(dive* affectedDive);
+	void undo();
+	void redo();
+};
+
 class UndoBuffer : public QObject
 {
 	Q_OBJECT