Add a utility to make root command line parsing of splitlevel=99 TrkA…

…na trees easier

(cherry picked from commit e2c80ad)

examples/TrkAnaUtils.C

@@ -0,0 +1,126 @@
+//
+//  Utility macros for inspecting TrkAna files for use from the root prompt.  As an example, running from
+//  a muse directory with TrkAna included:
+//  > root -l
+//  root> #include TrkAna/examples/TrkAnaUtils.C
+//  root> TrkAnaUtils tau("MyTrkAnaFile.cc");
+//  root> tau.ListTrees(); // lists available TrkAna tree (TDirectories)
+//  root> tau.UseTree("TrkAnaNeg"); // use the tree based on downstream negative electron tracks
+//  root> tau.ListBranches(); // list the available branches
+//  root> tau.ListSubbranches("deent"); // list sub-branches for the downstream negative elecgtron branch
+//  root> tau.ListLeaves("hcnt."); // list leaves in the hitcount branch
+//  root> tau.Draw("deent.mom.Theta():deent.pos.Y()","hcnt.nbkg<400","colorz"); // Draw a plot
+//
+//  Original author: Dave Brown (LBNL)
+//
+#include <iostream>
+#include <string>
+class TrkAnaUtils {
+  public:
+    TrkAnaUtils(const char* filename);
+    ~TrkAnaUtils() { delete myfile_; }
+    TFile const& File() const { return *myfile_; }
+    void ListTrees() const;
+    void UseTree(const char* treename="TrkAnaNeg");
+    void fileName() { return myfile_->GetName(); }
+    void treeName() { if(mytree_)return mytree_->GetName(); else std::cout << "No current tree" << std::endl; }
+    TFile* file() { return myfile_;}
+    TTree* tree() { return mytree_;}
+    void ListBranches() const;
+    void ListSubbranches(const char* branch) const;
+    void ListLeaves(const char* branch) const;
+    void Draw(const char* lname,const char* cut="", const char* gopt="") const;
+  private:
+    TFile* myfile_;
+    TTree* mytree_;
+};
+
+TrkAnaUtils::TrkAnaUtils(const char* filename) :  mytree_(0) {
+  myfile_ = new TFile(filename);
+}
+
+void TrkAnaUtils::ListTrees() const {
+  TObjArray* keylist = (TObjArray*)myfile_->GetListOfKeys();
+  int nkeys = keylist->GetEntries();
+  for(int ikey=0;ikey<nkeys;++ikey){
+    auto key = keylist->At(ikey);
+    std::string kname(key->GetName());
+    if(0 == kname.compare(0,6,std::string("TrkAna")))
+      std::cout << kname << std::endl;
+  }
+}
+
+void TrkAnaUtils::UseTree( const char* treename) {
+  TObjArray* keylist = (TObjArray*)myfile_->GetListOfKeys();
+  int nkeys = keylist->GetEntries();
+  for(int ikey=0;ikey<nkeys;++ikey){
+    auto key = keylist->At(ikey);
+    std::string kname(key->GetName());
+    if(0 == kname.compare(std::string(treename))){
+      auto td = (TDirectory*)myfile_->GetDirectory(treename);
+      if(td){
+        mytree_ = (TTree*)td->Get("trkana");
+          if(!mytree_)
+            std::cout <<"Error: can't find TrkAna tree in TDirectory " << treename << std::endl;
+      } else
+        std::cout <<"Error: can't find TDirectory " << treename << std::endl;
+    }
+  }
+}
+
+void TrkAnaUtils::ListBranches() const {
+  if(mytree_){
+    auto blist = mytree_->GetListOfBranches();
+    int nbs = blist->GetEntries();
+    for(int ib=0;ib<nbs;++ib){
+      auto b = blist->At(ib);
+      std::cout << b->GetName() << std::endl;
+    }
+  } else {
+    std::cout << "No current tree; call UseTree to set current tree" << std::endl;
+  }
+}
+
+void TrkAnaUtils::ListSubbranches(const char* branch) const {
+  if(mytree_){
+    auto bran = mytree_->GetBranch(branch);
+    if(bran){
+      auto blist = bran->GetListOfBranches();
+      int nbs = blist->GetEntries();
+      for(int ib=0;ib<nbs;++ib){
+        auto b = blist->At(ib);
+        std::cout << b->GetName() << std::endl;
+      }
+    } else {
+      std::cout << "Current tree has no branch" << branch << std::endl;
+    }
+  } else {
+    std::cout << "No current tree; call UseTree to set current tree" << std::endl;
+  }
+}
+
+void TrkAnaUtils::ListLeaves(const char* branch) const {
+  if(mytree_){
+    auto bran = mytree_->GetBranch(branch);
+    if(bran){
+      auto blist = bran->GetListOfLeaves();
+      int nbs = blist->GetEntries();
+      for(int ib=0;ib<nbs;++ib){
+        auto b = blist->At(ib);
+        std::cout << b->GetName() << std::endl;
+      }
+    } else {
+      std::cout << "Current tree has no branch" << branch << std::endl;
+    }
+  } else {
+    std::cout << "No current tree; call UseTree to set current tree" << std::endl;
+  }
+}
+
+void TrkAnaUtils::Draw(const char* lname,const char* cut="", const char* gopt="") const {
+  if(mytree_){
+    mytree_->Draw(lname,cut,gopt);
+  } else {
+    std::cout << "No current tree; call UseTree to set current tree" << std::endl;
+  }
+}