implemented saving/loading for groups

app/common/xmlutils.h

@@ -31,6 +31,7 @@ namespace olive {
 class Block;
 class Node;
 class NodeInput;
+class NodeGroup;
 
 #define XMLAttributeLoop(reader, item) \
   foreach (const QXmlStreamAttribute& item, reader->attributes())
@@ -49,14 +50,23 @@ struct XMLNodeData {
     quintptr link;
   };
 
+  struct GroupLink {
+    NodeGroup *group;
+    quintptr input_node;
+    QString input_id;
+    int input_element;
+  };
+
   QHash<quintptr, Node*> node_ptrs;
   QList<SerializedConnection> desired_connections;
   QList<BlockLink> block_links;
+  QVector<GroupLink> group_input_links;
+  QHash<NodeGroup*, quintptr> group_output_links;
+
+  void PostConnect(uint version, MultiUndoCommand *command = nullptr) const;
 
 };
 
-void XMLConnectNodes(const XMLNodeData& xml_node_data, uint version, MultiUndoCommand *command = nullptr);
-
 /**
  * @brief Workaround for QXmlStreamReader::readNextStartElement not detecting the end of a document
  *
@@ -68,8 +78,6 @@ void XMLConnectNodes(const XMLNodeData& xml_node_data, uint version, MultiUndoCo
  */
 bool XMLReadNextStartElement(QXmlStreamReader* reader);
 
-void XMLLinkBlocks(const XMLNodeData& xml_node_data);
-
 }
 
 #endif // XMLREADLOOP_H