Support for multiple connections for a single input port

- added NodeDataModel::portInConnectionPolicy (similar to NodeDataModel::portOutConnectionPolicy)
- added a new parameter to NodeDataModel::setInData representing the respective connection
- modified NodeConnectionInteraction::disconnect to only erase one connection from the port rather than clear all connections

Author: vhutter

examples/example2/TextDisplayDataModel.hpp

@@ -8,6 +8,7 @@
 #include <nodes/NodeDataModel>
 
 #include <iostream>
+#include <vector>
 
 using QtNodes::PortType;
 using QtNodes::PortIndex;
@@ -54,20 +55,45 @@ class TextDisplayDataModel : public NodeDataModel
   std::shared_ptr<NodeData>
   outData(PortIndex port) override;
 
+  ConnectionPolicy
+  portInConnectionPolicy(PortIndex) const override
+  {
+    return ConnectionPolicy::Many;
+  }
+
   void
   setInData(std::shared_ptr<NodeData> data, int) override
+  {
+  }
+
+  void
+  setInData(std::shared_ptr<NodeData> data, int, const QUuid& connectionId) override
   {
     auto textData = std::dynamic_pointer_cast<TextData>(data);
 
+    auto it = std::find_if(inputTexts.begin(), inputTexts.end(),
+        [this, &connectionId](const auto& e)
+        {
+            return e.first == connectionId;
+        });
     if (textData)
     {
-      _label->setText(textData->text());
+      if (it == inputTexts.end())
+        inputTexts.emplace_back(connectionId, textData->text());
+      else
+        it->second = textData->text();
     }
     else
     {
-      _label->clear();
+      inputTexts.erase(it);
     }
 
+    QStringList textList;
+    for (auto&& entry : inputTexts) textList.push_back(entry.second);
+
+    _label->setText(QStringLiteral("%1 inputs: %2")
+        .arg(textList.size())
+        .arg(textList.join(QStringLiteral(", "))));
     _label->adjustSize();
   }
 
@@ -77,4 +103,5 @@ class TextDisplayDataModel : public NodeDataModel
 private:
 
   QLabel * _label;
+  std::vector<std::pair<QUuid, QString>> inputTexts;
 };

examples/example2/TextSourceDataModel.cpp

@@ -2,7 +2,8 @@
 
 TextSourceDataModel::
 TextSourceDataModel()
-  : _lineEdit(new QLineEdit("Default Text"))
+  : _lineEdit(new QLineEdit("Default Text")),
+    _textData(std::make_shared<TextData>())
 {
   connect(_lineEdit, &QLineEdit::textEdited,
           this, &TextSourceDataModel::onTextEdited);
@@ -54,5 +55,6 @@ std::shared_ptr<NodeData>
 TextSourceDataModel::
 outData(PortIndex)
 {
-  return std::make_shared<TextData>(_lineEdit->text());
+  *_textData = TextData(_lineEdit->text());
+  return _textData;
 }

examples/example2/TextSourceDataModel.hpp

@@ -69,4 +69,5 @@ private Q_SLOTS:
 private:
 
   QLineEdit * _lineEdit;
+  std::shared_ptr<TextData> _textData;
 };

include/nodes/internal/DataModelRegistry.hpp

@@ -19,15 +19,6 @@
 namespace QtNodes
 {
 
-inline
-bool
-operator<(QtNodes::NodeDataType const & d1,
-          QtNodes::NodeDataType const & d2)
-{
-  return d1.id < d2.id;
-}
-
-
 /// Class uses map for storing models (name, model)
 class NODE_EDITOR_PUBLIC DataModelRegistry
 {
@@ -40,7 +31,8 @@ class NODE_EDITOR_PUBLIC DataModelRegistry
   using RegisteredModelsCategoryMap = std::unordered_map<QString, QString>;
   using CategoriesSet = std::set<QString>;
 
-  using RegisteredTypeConvertersMap = std::map<TypeConverterId, TypeConverter>;
+  using RegisteredTypeConvertersMap = std::unordered_map<
+      TypeConverterId, TypeConverter, TypeConverterIdHash>;
 
   DataModelRegistry()  = default;
   ~DataModelRegistry() = default;

include/nodes/internal/Node.hpp

@@ -90,7 +90,8 @@ public Q_SLOTS: // data propagation
   /// Propagates incoming data to the underlying model.
   void
   propagateData(std::shared_ptr<NodeData> nodeData,
-                PortIndex inPortIndex) const;
+                PortIndex inPortIndex,
+                const QUuid& connectionId) const;
 
   /// Fetches data from model's OUT #index port
   /// and propagates it to the connection

include/nodes/internal/NodeData.hpp

@@ -11,6 +11,18 @@ struct NodeDataType
 {
   QString id;
   QString name;
+
+  friend bool operator<(QtNodes::NodeDataType const& d1,
+      QtNodes::NodeDataType const& d2)
+  {
+      return d1.id < d2.id;
+  }
+
+  friend bool operator==(const QtNodes::NodeDataType& d1,
+      const QtNodes::NodeDataType& d2) noexcept
+  {
+      return d1.id == d2.id;
+  }
 };
 
 /// Class represents data transferred between nodes.

include/nodes/internal/NodeDataModel.hpp

@@ -87,6 +87,13 @@ class NODE_EDITOR_PUBLIC NodeDataModel
     return ConnectionPolicy::Many;
   }
 
+  virtual
+  ConnectionPolicy
+  portInConnectionPolicy(PortIndex) const
+  {
+    return ConnectionPolicy::One;
+  }
+
   NodeStyle const&
   nodeStyle() const;
 
@@ -101,6 +108,17 @@ class NODE_EDITOR_PUBLIC NodeDataModel
   setInData(std::shared_ptr<NodeData> nodeData,
             PortIndex port) = 0;
 
+  // Use this if portInConnectionPolicy returns ConnectionPolicy::Many
+  virtual
+  void
+  setInData(std::shared_ptr<NodeData> nodeData,
+            PortIndex port,
+            const QUuid& connectionId)
+  {
+    Q_UNUSED(connectionId);
+    setInData(nodeData, port);
+  }
+
   virtual
   std::shared_ptr<NodeData>
   outData(PortIndex port) = 0;

include/nodes/internal/TypeConverter.hpp

@@ -18,4 +18,13 @@ using TypeConverter =
 using TypeConverterId =
   std::pair<NodeDataType, NodeDataType>;
 
+struct TypeConverterIdHash
+{
+    std::size_t operator()(const QtNodes::TypeConverterId& converter) const noexcept
+    {
+        return qHash(converter.first.id)
+            ^ qHash(converter.second.id);
+    }
+};
+
 }

src/Connection.cpp

@@ -435,7 +435,7 @@ propagateData(std::shared_ptr<NodeData> nodeData) const
       nodeData = _converter(nodeData);
     }
 
-    _inNode->propagateData(nodeData, _inPortIndex);
+    _inNode->propagateData(nodeData, _inPortIndex, id());
   }
 }
 

src/Node.cpp

@@ -185,9 +185,10 @@ nodeDataModel() const
 void
 Node::
 propagateData(std::shared_ptr<NodeData> nodeData,
-              PortIndex inPortIndex) const
+              PortIndex inPortIndex,
+              const QUuid& connectionId) const
 {
-  _nodeDataModel->setInData(std::move(nodeData), inPortIndex);
+  _nodeDataModel->setInData(std::move(nodeData), inPortIndex, connectionId);
 
   //Recalculate the nodes visuals. A data change can result in the node taking more space than before, so this forces a recalculate+repaint on the affected node
   _nodeGraphicsObject->setGeometryChanged();