completed prototype of background service that traverse the graph

app/node/processor/renderer/renderpath.cpp

@@ -0,0 +1,88 @@
+#include "renderpath.h"
+
+RenderPath::RenderPath(int max_threads) :
+  finalized_(false)
+{
+  Q_ASSERT(max_threads > 0);
+
+  render_path_.resize(max_threads);
+}
+
+void RenderPath::AddEntry(Node *node, int thread, int index)
+{
+  if (finalized_) {
+    return;
+  }
+
+  RenderThreadPath& thread_path = render_path_[thread];
+
+  // Make sure there are enough indices for this entry
+  while (thread_path.size() < index) {
+    thread_path.append(nullptr);
+  }
+
+  thread_path.append(node);
+  thread_map_.insert(node, thread);
+}
+
+void RenderPath::RemoveEntry(Node *node)
+{
+  if (finalized_) {
+    return;
+  }
+
+  Q_ASSERT(thread_map_.contains(node));
+
+  int node_thread = thread_map_[node];
+
+  render_path_[node_thread].replace(NodeIndexInThread(node, node_thread), nullptr);
+  thread_map_.remove(node);
+}
+
+int RenderPath::ContainsNode(Node *node)
+{
+  if (thread_map_.contains(node)) {
+    return thread_map_[node];
+  }
+  return -1;
+}
+
+int RenderPath::NodeIndex(Node *node)
+{
+  if (thread_map_.contains(node)) {
+    return NodeIndexInThread(node, thread_map_[node]);
+  }
+  return -1;
+}
+
+int RenderPath::NodeIndexInThread(Node *node, int thread)
+{
+  return render_path_[thread].indexOf(node);
+}
+
+void RenderPath::Finalize()
+{
+  for (int i=0;i<render_path_.size();i++) {
+    render_path_[i].removeAll(nullptr);
+  }
+
+  finalized_ = true;
+}
+
+int RenderPath::FindAvailableThreadAtIndex(int index)
+{
+  for (int i=0;i<render_path_.size();i++) {
+    QVector<Node*>& thread_path_ = render_path_[i];
+
+    if (index >= thread_path_.size() || thread_path_.at(index) == nullptr) {
+      return i;
+    }
+  }
+
+  return -1;
+}
+
+RenderThreadPath &RenderPath::GetThreadPath(int thread)
+{
+  return render_path_[thread];
+}