[main] RootObjTree: add NodeFullPath

Author: silverweed

main/src/RootObjTree.cxx

@@ -155,3 +155,17 @@ ROOT::CmdLine::ParseRootSources(const std::vector<std::string> &sourcesRaw, std:
 
    return sources;
 }
+
+std::string ROOT::CmdLine::NodeFullPath(const ROOT::CmdLine::RootObjTree &tree, ROOT::CmdLine::NodeIdx_t nodeIdx,
+                                        ROOT::CmdLine::ENodeFullPathOpt opt)
+{
+   const RootObjNode *node = &tree.fNodes[nodeIdx];
+   std::string fullPath = node->fName;
+   while (node->fParent != 0) {
+      node = &tree.fNodes[node->fParent];
+      fullPath = node->fName + (fullPath.empty() ? "" : "/") + fullPath;
+   }
+   if (opt == ENodeFullPathOpt::kIncludeFilename && nodeIdx > 0)
+      fullPath = tree.fNodes[0].fName + ":" + fullPath;
+   return fullPath;
+}

main/src/RootObjTree.hxx

@@ -56,6 +56,14 @@ struct RootObjTree {
    std::unique_ptr<TFile> fFile;
 };
 
+enum class ENodeFullPathOpt {
+   kExcludeFilename,
+   kIncludeFilename,
+};
+/// Given a node, returns its full path. If `opt == kIncludeFilename`, the path is prepended by "filename.root:"
+std::string
+NodeFullPath(const RootObjTree &tree, NodeIdx_t nodeIdx, ENodeFullPathOpt opt = ENodeFullPathOpt::kExcludeFilename);
+
 struct RootSource {
    std::string fFileName;
    RootObjTree fObjectTree;