add/remove edge are undo commands

include/commands.h

@@ -9,6 +9,8 @@
 class GraphLogic;
 
 
+// exceptions:
+
 class NoActiveNodeException : public std::exception
 {
 public:
@@ -27,7 +29,20 @@ public:
     const char* what() const throw();
 };
 
+class BaseNodeCannotBeEdgeTargetException : public std::exception
+{
+public:
+    const char* what() const throw();
+};
+
+class EdgeExistsBetweenNodesException : public std::exception
+{
+public:
+    const char* what() const throw();
+};
+
 
+// commands:
 
 class InsertNodeCommand : public QUndoCommand
 {
@@ -70,4 +85,44 @@ private:
     QList <Edge *> m_edgeList;
 };
 
+class AddEdgeCommand : public QUndoCommand
+{
+
+public:
+
+    AddEdgeCommand(GraphLogic *graphLogic, Node *source, Node *destinaion);
+
+    void undo();
+    void redo();
+
+private:
+
+    GraphLogic *m_graphLogic;
+
+    Node *m_activeNode;
+    Node *m_source;
+    Node *m_destination;
+    Edge *m_edge;
+};
+
+class RemoveEdgeCommand : public QUndoCommand
+{
+
+public:
+
+    RemoveEdgeCommand(GraphLogic *graphLogic, Node *source, Node *destinaion);
+
+    void undo();
+    void redo();
+
+private:
+
+    GraphLogic *m_graphLogic;
+
+    Node *m_activeNode;
+    Node *m_source;
+    Node *m_destination;
+    Edge *m_edge;
+};
+
 #endif // COMMANDS_H

include/graphlogic.h

@@ -13,6 +13,8 @@ class GraphWidget;
 
 class InsertNodeCommand;
 class RemoveNodeCommand;
+class AddEdgeCommand;
+class RemoveEdgeCommand;
 
 class GraphLogic : public QObject
 {
@@ -34,15 +36,15 @@ public:
 public slots:
 
     // commands from toolbars:
-    void insertNode();
-    void removeNode();  /// @todo Rewrite as an undo action
+    void insertNode();  // undo command
+    void removeNode();  // undo command
     void nodeEdited();  /// @todo Rewrite as an undo action
     void scaleUp();     /// @todo Rewrite as an undo action
     void scaleDown();   /// @todo Rewrite as an undo action
     void nodeColor();
     void nodeTextColor();
-    void addEdge();     /// @todo Rewrite as an undo action
-    void removeEdge();  /// @todo Rewrite as an undo action
+    void addEdge();
+    void removeEdge();
     void hintMode();
     void insertPicture(const QString &picture); /// @todo Rewrite as an undo action
 
@@ -78,8 +80,8 @@ private:
 
     // functions on the edges
     QList<Edge *> allEdges() const;
-    void addEdge(Node *source, Node *destination);
-    void removeEdge(Node* source, Node *destination);
+    void addEdge(Node *source, Node *destination);      // undo command
+    void removeEdge(Node* source, Node *destination);   // undo command
 
     // hint mode's nodenumber handling functions
     void showNodeNumbers();
@@ -104,6 +106,8 @@ private:
 
     friend class InsertNodeCommand;
     friend class RemoveNodeCommand;
+    friend class AddEdgeCommand;
+    friend class RemoveEdgeCommand;
 };
 
 #endif // GRAPHLOGIC_H

src/commands.cpp

@@ -23,6 +23,17 @@ const char* CannotDeleteBaseNodeException::what() const throw()
     return QObject::tr("Base node cannot be deleted.").toStdString().c_str();
 }
 
+const char* BaseNodeCannotBeEdgeTargetException::what() const throw()
+{
+    return QObject::tr("Base node cannot be a target.").toStdString().c_str();
+}
+
+const char* EdgeExistsBetweenNodesException::what() const throw()
+{
+    return QObject::tr("There is already an edge between these two nodes.").
+            toStdString().c_str();
+}
+
 
 InsertNodeCommand::InsertNodeCommand(GraphLogic *graphLogic)
     : m_graphLogic(graphLogic)
@@ -191,3 +202,100 @@ void RemoveNodeCommand::redo()
     if (m_graphLogic->m_showingNodeNumbers)
         m_graphLogic->showNodeNumbers();
 }
+
+AddEdgeCommand::AddEdgeCommand(GraphLogic *graphLogic, Node *source, Node *destinaion)
+    : m_graphLogic(graphLogic)
+    , m_activeNode(m_graphLogic->m_activeNode)
+    , m_source(source)
+    , m_destination(destinaion)
+{
+    if (!m_activeNode)
+        throw NoActiveNodeException();
+
+    if (m_destination == m_graphLogic->m_nodeList.first())
+        throw BaseNodeCannotBeEdgeTargetException();
+
+
+    if (m_source->isConnected(m_destination))
+        throw EdgeExistsBetweenNodesException();
+
+    setText(QObject::tr("Edge added between \"").append(
+                m_source->toPlainText()).append(
+                QObject::tr("\" and \"").append(
+                m_destination->toPlainText()).append("\"")));
+
+
+    // aviod the graph beeing acyclic. (ok, Nodes having multiple parents)
+    bool sec(false);
+    if (!m_destination->edgesToThis().empty())
+    {
+        emit m_graphLogic->notification(
+           QObject::tr("The graph is acyclic, edge added as secondary edge."));
+        sec = true;
+    }
+
+    m_edge = new Edge(m_source, m_destination);
+    m_edge->setColor(m_destination->color());
+    m_edge->setWidth(m_destination->scale()*2 + 1);
+
+    // The Edge is secondary, because the Node already has a parent
+    // (it is already a destination of another Edge)
+    m_edge->setSecondary(sec);
+}
+
+void AddEdgeCommand::undo()
+{
+    m_source->removeEdge(m_edge);
+    m_destination->removeEdge(m_edge);
+    m_graphLogic->m_graphWidget->scene()->removeItem(m_edge);
+
+    m_graphLogic->setActiveNode(m_activeNode);
+
+    emit  m_graphLogic->contentChanged(false);
+}
+
+void AddEdgeCommand::redo()
+{
+    m_source->addEdge(m_edge, true);
+    m_destination->addEdge(m_edge, false);
+
+    m_graphLogic->m_graphWidget->scene()->addItem(m_edge);
+
+    m_graphLogic->setActiveNode(m_destination);
+    emit m_graphLogic->contentChanged();
+}
+
+RemoveEdgeCommand::RemoveEdgeCommand(GraphLogic *graphLogic, Node *source, Node *destinaion)
+    : m_graphLogic(graphLogic)
+    , m_activeNode(m_graphLogic->m_activeNode)
+    , m_source(source)
+    , m_destination(destinaion)
+    , m_edge(source->edgeTo(destinaion))
+{
+    setText(QObject::tr("Edge releted between \"").append(
+            m_source->toPlainText()).append(
+            QObject::tr("\" and \"").append(
+            m_destination->toPlainText()).append("\"")));
+}
+
+void RemoveEdgeCommand::undo()
+{
+    m_source->addEdge(m_edge, true);
+    m_destination->addEdge(m_edge, false);
+
+    m_graphLogic->m_graphWidget->scene()->addItem(m_edge);
+
+    m_graphLogic->setActiveNode(m_destination);
+    emit m_graphLogic->contentChanged(false);
+}
+
+void RemoveEdgeCommand::redo()
+{
+    m_source->removeEdge(m_edge);
+    m_destination->removeEdge(m_edge);
+    m_graphLogic->m_graphWidget->scene()->removeItem(m_edge);
+
+    m_graphLogic->setActiveNode(m_activeNode);
+
+    emit  m_graphLogic->contentChanged();
+}

src/graphlogic.cpp

@@ -699,51 +699,16 @@ QList<Edge *> GraphLogic::allEdges() const
 
 void GraphLogic::addEdge(Node *source, Node *destination)
 {
-    if (!m_activeNode)
+    try
     {
-        emit notification(tr("No active node."));
-        return;
+        QUndoCommand *addEdgeCommand = new AddEdgeCommand(this, source, destination);
+        m_undoStack->push(addEdgeCommand);
     }
-
-    if (destination == m_nodeList.first())
+    catch (std::exception &e)
     {
-        setActiveNode(destination);
-        emit notification(
-                    tr("Root element cannot be an edge target."));
+        emit notification(e.what());
         return;
     }
-
-    if (source->isConnected(destination))
-    {
-        setActiveNode(destination);
-        emit notification(
-                    tr("There is already an edge between these two nodes."));
-    }
-    else
-    {
-        // aviod the graph beeing acyclic. (ok, Nodes having multiple parents)
-        bool sec(false);
-        if (!destination->edgesToThis().empty())
-        {
-            emit notification(
-                     tr("The graph is acyclic, edge added as secondary edge."));
-            sec = true;
-        }
-        Edge *edge = new Edge(source, destination);
-        source->addEdge(edge, true);
-        destination->addEdge(edge, false);
-
-        edge->setColor(destination->color());
-        edge->setWidth(destination->scale()*2 + 1);
-
-        // The Edge is secondary, because the Node already has a parent
-        // (it is already a destination of another Edge)
-        edge->setSecondary(sec);
-        m_graphWidget->scene()->addItem(edge);
-
-        setActiveNode(destination);
-        emit contentChanged();
-    }
 }
 
 void GraphLogic::removeEdge(Node *source, Node *destination)