Compositor: Add Streaming Operator for NodeOperationBuilder.

For debugging purposes to convert the internal state of the
NodeOperationBuilder to a graphviz.

Usage:

	std::cout << *this << "\n";

Inside any method of the NodeOperationBuilder.

source/blender/compositor/intern/COM_NodeOperation.cc

@@ -259,17 +259,18 @@ std::ostream &operator<<(std::ostream &os, const NodeOperation &node_operation)
 {
   NodeOperationFlags flags = node_operation.get_flags();
   os << "NodeOperation(";
+  os << "id=" << node_operation.get_id();
   if (!node_operation.get_name().empty()) {
-    os << "name=" << node_operation.get_name() << ",";
+    os << ",name=" << node_operation.get_name();
   }
-  os << "flags={" << flags << "},";
+  os << ",flags={" << flags << "}";
   if (flags.is_read_buffer_operation) {
     const ReadBufferOperation *read_operation = (const ReadBufferOperation *)&node_operation;
     const MemoryProxy *proxy = read_operation->getMemoryProxy();
     if (proxy) {
       const WriteBufferOperation *write_operation = proxy->getWriteBufferOperation();
       if (write_operation) {
-        os << "write=" << (NodeOperation &)*write_operation << ",";
+        os << ",write=" << (NodeOperation &)*write_operation;
       }
     }
   }

source/blender/compositor/intern/COM_NodeOperation.h

@@ -251,6 +251,7 @@ struct NodeOperationFlags {
  */
 class NodeOperation {
  private:
+  int m_id;
   std::string m_name;
   Vector<NodeOperationInput> m_inputs;
   Vector<NodeOperationOutput> m_outputs;
@@ -307,6 +308,16 @@ class NodeOperation {
     return m_name;
   }
 
+  void set_id(const int id)
+  {
+    m_id = id;
+  }
+
+  const int get_id() const
+  {
+    return m_id;
+  }
+
   const NodeOperationFlags get_flags() const
   {
     return flags;

source/blender/compositor/intern/COM_NodeOperationBuilder.cc

@@ -124,6 +124,7 @@ void NodeOperationBuilder::convertToOperations(ExecutionSystem *system)
 
 void NodeOperationBuilder::addOperation(NodeOperation *operation)
 {
+  operation->set_id(m_operations.size());
   m_operations.append(operation);
   if (m_current_node) {
     operation->set_name(m_current_node->getbNode()->name);
@@ -691,4 +692,41 @@ void NodeOperationBuilder::group_operations()
   }
 }
 
+/** Create a graphviz representation of the NodeOperationBuilder. */
+std::ostream &operator<<(std::ostream &os, const NodeOperationBuilder &builder)
+{
+  os << "# Builder start\n";
+  os << "digraph  G {\n";
+  os << "    rankdir=LR;\n";
+  os << "    node [shape=box];\n";
+  for (const NodeOperation *operation : builder.get_operations()) {
+    os << "    op" << operation->get_id() << " [label=\"" << *operation << "\"];\n";
+  }
+
+  os << "\n";
+  for (const NodeOperationBuilder::Link &link : builder.get_links()) {
+    os << "    op" << link.from()->getOperation().get_id() << " -> op"
+       << link.to()->getOperation().get_id() << ";\n";
+  }
+  for (const NodeOperation *operation : builder.get_operations()) {
+    if (operation->get_flags().is_read_buffer_operation) {
+      const ReadBufferOperation &read_operation = static_cast<const ReadBufferOperation &>(
+          *operation);
+      const WriteBufferOperation &write_operation =
+          *read_operation.getMemoryProxy()->getWriteBufferOperation();
+      os << "    op" << write_operation.get_id() << " -> op" << read_operation.get_id() << ";\n";
+    }
+  }
+
+  os << "}\n";
+  os << "# Builder end\n";
+  return os;
+}
+
+std::ostream &operator<<(std::ostream &os, const NodeOperationBuilder::Link &link)
+{
+  os << link.from()->getOperation().get_id() << " -> " << link.to()->getOperation().get_id();
+  return os;
+}
+
 }  // namespace blender::compositor

source/blender/compositor/intern/COM_NodeOperationBuilder.h

@@ -119,6 +119,16 @@ class NodeOperationBuilder {
     return m_active_viewer;
   }
 
+  const Vector<NodeOperation *> &get_operations() const
+  {
+    return m_operations;
+  }
+
+  const Vector<Link> &get_links() const
+  {
+    return m_links;
+  }
+
  protected:
   /** Add datatype conversion where needed */
   void add_datatype_conversions();
@@ -160,4 +170,7 @@ class NodeOperationBuilder {
 #endif
 };
 
+std::ostream &operator<<(std::ostream &os, const NodeOperationBuilder &builder);
+std::ostream &operator<<(std::ostream &os, const NodeOperationBuilder::Link &link);
+
 }  // namespace blender::compositor