timeline: avoid duplicate items or item dependencies when pasting

God damn this was a big oof. Pasting was inadvertently making duplicates of the footage node(s) every single time. Worst case was if the clip was connected to a nested sequence. Every time someone copy/pasted in my large-scale project, it would add another 1000 nodes to the project. It's about fucking time this was fixed.

app/node/project/serializer/serializer.cpp

@@ -136,7 +136,7 @@ ProjectSerializer::Result ProjectSerializer::Load(Project *project, QXmlStreamRe
   return res;
 }
 
-ProjectSerializer::Result ProjectSerializer::Paste(LoadType load_type)
+ProjectSerializer::Result ProjectSerializer::Paste(LoadType load_type, Project *project)
 {
   QString clipboard = Core::PasteStringFromClipboard();
   if (clipboard.isEmpty()) {
@@ -145,7 +145,7 @@ ProjectSerializer::Result ProjectSerializer::Paste(LoadType load_type)
 
   QXmlStreamReader reader(clipboard);
 
-  return ProjectSerializer::Load(nullptr, &reader, load_type);
+  return ProjectSerializer::Load(project, &reader, load_type);
 }
 
 ProjectSerializer::Result ProjectSerializer::Save(const SaveData &data, bool compress)

app/node/project/serializer/serializer.h

@@ -81,6 +81,8 @@ public:
 
     QVector<Node*> nodes;
 
+    Node::OutputConnections promised_connections;
+
   };
 
   class Result
@@ -171,7 +173,7 @@ public:
 
   static Result Load(Project *project, const QString &filename, LoadType load_type);
   static Result Load(Project *project, QXmlStreamReader *read_device, LoadType load_type);
-  static Result Paste(LoadType load_type);
+  static Result Paste(LoadType load_type, Project *project = nullptr);
 
   static Result Save(const SaveData &data, bool compress);
   static Result Save(QXmlStreamWriter *write_device, const SaveData &data);

app/node/project/serializer/serializer230220.cpp

@@ -175,13 +175,25 @@ ProjectSerializer230220::LoadData ProjectSerializer230220::Load(Project *project
   case kOnlyNodes:
   {
     if (reader->name() == QStringLiteral("nodes")) {
+      QMap<quintptr, Node*> skipped_items;
+
       while (XMLReadNextStartElement(reader)) {
         if (reader->name() == QStringLiteral("node")) {
           QString id;
+          quintptr ptr = 0;
+          QVector<quintptr> items;
 
           XMLAttributeLoop(reader, attr) {
             if (attr.name() == QStringLiteral("id")) {
               id = attr.value().toString();
+            } else if (attr.name() == QStringLiteral("ptr")) {
+              ptr = attr.value().toULongLong();
+            } else if (attr.name() == QStringLiteral("items")) {
+              QVector<QStringRef> l = attr.value().split(',');
+              items.reserve(l.size());
+              for (const QStringRef &s : l) {
+                items.append(s.toULongLong());
+              }
             }
           }
 
@@ -189,15 +201,49 @@ ProjectSerializer230220::LoadData ProjectSerializer230220::Load(Project *project
             qWarning() << "Failed to load node with empty ID";
             reader->skipCurrentElement();
           } else {
-            Node* node = NodeFactory::CreateFromID(id);
-            if (!node) {
-              qWarning() << "Failed to find node with ID" << id;
+            bool dependency_of_item = false;
+
+            if (project && !items.empty()) {
+              for (quintptr p : items) {
+                if (project->nodes().contains(reinterpret_cast<Node*>(p))) {
+                  dependency_of_item = true;
+                  break;
+                }
+              }
+            }
+
+            if (dependency_of_item) {
               reader->skipCurrentElement();
             } else {
-              // Disable cache while node is being loaded (we'll re-enable it later)
-              node->SetCachesEnabled(false);
-              node->Load(reader, &project_data);
-              load_data.nodes.append(node);
+              Node* node = NodeFactory::CreateFromID(id);
+              if (!node) {
+                qWarning() << "Failed to find node with ID" << id;
+                reader->skipCurrentElement();
+              } else {
+                if (project && node->IsItem() && ptr) {
+                  // If we're pasting an object into the same project, we should re-use the item
+                  // rather than duplicate.
+                  Node *existing = reinterpret_cast<Node *>(ptr);
+                  if (project->nodes().contains(existing)) {
+                    // Connect this
+                    skipped_items.insert(ptr, existing);
+
+                    // Don't continue loading this
+                    delete node;
+                    node = nullptr;
+
+                    // Skip element
+                    reader->skipCurrentElement();
+                  }
+                }
+
+                if (node) {
+                  // Disable cache while node is being loaded (we'll re-enable it later)
+                  node->SetCachesEnabled(false);
+                  node->Load(reader, &project_data);
+                  load_data.nodes.append(node);
+                }
+              }
             }
           }
         } else if (reader->name() == QStringLiteral("properties")) {
@@ -230,6 +276,21 @@ ProjectSerializer230220::LoadData ProjectSerializer230220::Load(Project *project
         }
       }
 
+      if (!skipped_items.empty()) {
+        for (auto it = project_data.desired_connections.begin(); it != project_data.desired_connections.end(); ) {
+          const SerializedData::SerializedConnection &sc = *it;
+
+          if (Node *si = skipped_items.value(sc.output_node)) {
+            // Convert this to a promised connection
+            Node::OutputConnection oc = {si, sc.input};
+            load_data.promised_connections.push_back(oc);
+            it = project_data.desired_connections.erase(it);
+          } else {
+            it++;
+          }
+        }
+      }
+
       PostConnect(load_data.nodes, &project_data);
 
       // Resolve serialized properties (if any)
@@ -249,6 +310,21 @@ ProjectSerializer230220::LoadData ProjectSerializer230220::Load(Project *project
   return load_data;
 }
 
+void WriteNodeMap(QXmlStreamWriter *writer, Node *node, const QVector<Node*> &nodes)
+{
+  writer->writeStartElement(QStringLiteral("node"));
+
+  writer->writeAttribute(QStringLiteral("ptr"), QString::number(reinterpret_cast<quintptr>(node)));
+
+  for (auto oc : node->output_connections()) {
+    if (nodes.contains(oc.second.node())) {
+      WriteNodeMap(writer, oc.second.node(), nodes);
+    }
+  }
+
+  writer->writeEndElement();
+}
+
 void ProjectSerializer230220::Save(QXmlStreamWriter *writer, const SaveData &data, void *reserved) const
 {
   if (!data.GetOnlySerializeMarkers().empty()) {
@@ -325,8 +401,19 @@ void ProjectSerializer230220::Save(QXmlStreamWriter *writer, const SaveData &dat
 
     for (Node *n : data.GetOnlySerializeNodes()) {
       writer->writeStartElement(QStringLiteral("node"));
+
+      QStringList item_list;
+      for (Node *i : data.GetOnlySerializeNodes()) {
+        if (i->IsItem() && i->InputsFrom(n, true)) {
+          item_list.append(QString::number(reinterpret_cast<quintptr>(i)));
+        }
+      }
+      if (!item_list.empty()) {
+        writer->writeAttribute(QStringLiteral("items"), item_list.join(','));
+      }
+
       n->Save(writer);
-      writer->writeEndElement();
+      writer->writeEndElement(); // node
     }
 
     if (!data.GetProperties().empty()) {

app/node/serializeddata.h

@@ -60,7 +60,6 @@ struct SerializedData {
   QList<BlockLink> block_links;
   QVector<GroupLink> group_input_links;
   QHash<NodeGroup*, quintptr> group_output_links;
-  QHash<Node*, QUuid> node_uuids;
 
 };
 

app/widget/timelinewidget/timelinewidget.cpp

@@ -1938,7 +1938,7 @@ bool TimelineWidget::PasteInternal(bool insert)
     return false;
   }
 
-  ProjectSerializer::Result res = ProjectSerializer::Paste(ProjectSerializer::kOnlyNodes);
+  ProjectSerializer::Result res = ProjectSerializer::Paste(ProjectSerializer::kOnlyNodes, GetConnectedNode()->project());
   if (res.GetLoadData().nodes.isEmpty()) {
     return false;
   }
@@ -1953,6 +1953,13 @@ bool TimelineWidget::PasteInternal(bool insert)
     }
   }
 
+  qDebug() << "pasing" << res.GetLoadData().nodes.size() << "nodes";
+
+  for (auto it = res.GetLoadData().promised_connections.cbegin(); it != res.GetLoadData().promised_connections.cend(); it++) {
+    auto oc = *it;
+    command->add_child(new NodeEdgeAddCommand(oc.first, oc.second));
+  }
+
   rational paste_start = GetConnectedNode()->GetPlayhead();
 
   if (insert) {