Create UndoBuffer class

Add an empty UndoBuffer class. This will be built up on to
implement a working undo/redo mechanism.

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

qt-ui/undobuffer.cpp

@@ -0,0 +1,41 @@
+#include "undobuffer.h"
+
+UndoBuffer::UndoBuffer(QObject *parent) : QObject(parent)
+{
+
+}
+
+UndoBuffer::~UndoBuffer()
+{
+
+}
+
+bool UndoBuffer::canUndo()
+{
+
+}
+
+bool UndoBuffer::canRedo()
+{
+
+}
+
+void UndoBuffer::redo()
+{
+
+}
+
+void UndoBuffer::undo()
+{
+
+}
+
+void UndoBuffer::recordbefore(QString commandName, dive *affectedDive)
+{
+
+}
+
+void UndoBuffer::recordAfter(dive *affectedDive)
+{
+
+}

qt-ui/undobuffer.h

@@ -0,0 +1,24 @@
+#ifndef UNDOBUFFER_H
+#define UNDOBUFFER_H
+
+#include <QObject>
+#include "dive.h"
+
+class UndoBuffer : public QObject
+{
+	Q_OBJECT
+public:
+	explicit UndoBuffer(QObject *parent = 0);
+	~UndoBuffer();
+	bool canUndo();
+	bool canRedo();
+private:
+	int curIdx;
+public slots:
+	void redo();
+	void undo();
+	void recordbefore(QString commandName, dive *affectedDive);
+	void recordAfter(dive *affectedDive);
+};
+
+#endif // UNDOBUFFER_H

subsurface.pro

@@ -104,7 +104,8 @@ HEADERS = \
 	qt-ui/statistics/statisticsbar.h \
 	qt-ui/statistics/yearstatistics.h \
 	qt-ui/diveshareexportdialog.h \
-	qt-ui/filtermodels.h
+	qt-ui/filtermodels.h \
+	qt-ui/undobuffer.h
 
 android: HEADERS -= \
 	qt-ui/usermanual.h \
@@ -198,7 +199,8 @@ SOURCES =  \
 	qt-ui/statistics/statisticsbar.cpp \
 	qt-ui/statistics/monthstatistics.cpp \
 	qt-ui/diveshareexportdialog.cpp \
-	qt-ui/filtermodels.cpp
+	qt-ui/filtermodels.cpp \
+	qt-ui/undobuffer.cpp
 
 android: SOURCES += android.cpp
 else: win32: SOURCES += windows.c