RhodeCode

    ///

    void clear() {

      Parent::clear();

    }

    ///Split a node.

    ///This function splits a node. First a new node is added to the digraph,

    ///then the source of each outgoing arc of \c n is moved to this new node.

    ///If \c connect is \c true (this is the default value), then a new arc

    ///from \c n to the newly created node is also added.

    ///\return The newly created node.

    ///

    ///\note The <tt>Arc</tt>s

    ///referencing a moved arc remain

    ///valid. However <tt>InArc</tt>'s and <tt>OutArc</tt>'s

    ///may be invalidated.

    ///\warning This functionality cannot be used together with the Snapshot

    ///feature.

    Node split(Node n, bool connect = true)

    {

      Node b = addNode();

      nodes[b._id].first_out=nodes[n._id].first_out;

      nodes[n._id].first_out=-1;

      if(connect) addArc(n,b);

      return b;

    }

  public:

    class Snapshot;

  protected:

    void restoreSnapshot(const Snapshot &s)

    {

      while(s.arc_num<arcs.size()) {

        Arc arc = arcFromId(arcs.size()-1);

        Parent::notifier(Arc()).erase(arc);

        nodes[arcs.back().source].first_out=arcs.back().next_out;

        nodes[arcs.back().target].first_in=arcs.back().next_in;

        arcs.pop_back();

      }

      while(s.node_num<nodes.size()) {

        Node node = nodeFromId(nodes.size()-1);

        Parent::notifier(Node()).erase(node);

        nodes.pop_back();

      }