TConvertingBranchElement.cxx

Go to the documentation of this file.

/*
  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
*/
 
#include "RootConversions/TConvertingBranchElement.h"
#include "RootConversions/TConverterRegistry.h"
#include "RootConversions/TVirtualConverter.h"
#include "TClonesArray.h"
#include "TStreamerElement.h"
#include "TFile.h"
#include "TTree.h"
#include "TVirtualCollectionProxy.h"
#include "TVirtualCollectionIterators.h"
#include "TBranchRef.h"
#include "TClassEdit.h"
#include "TBasket.h"
#include "TError.h"
#include "TStreamerInfo.h"
#include "TBufferFile.h"
#include "TVirtualArray.h"
#include "TROOT.h"
#include <cassert>
#include <cstdlib>
 
 
std::atomic<bool> TConvertingBranchElement::fgDoDel = false;
 
 
namespace {
 
 
class TPushPopSafe
{
public:
  TVirtualCollectionProxy* fProxy;
  TPushPopSafe (TVirtualCollectionProxy* proxy, void* objectstart);
  inline ~TPushPopSafe();
};
 
 
inline TPushPopSafe::TPushPopSafe (TVirtualCollectionProxy* proxy,
                                   void* objectstart)
  : fProxy (proxy)
{
  if (fProxy)
    fProxy->PushProxy (objectstart);
}
 
 
inline TPushPopSafe::~TPushPopSafe()
{
  if (fProxy)
    fProxy->PopProxy();
}
 
 
void RemovePrefix(TString& str, const char* prefix)
{
  if (str.Length() && prefix && strlen(prefix)) {
    if (!str.Index(prefix)) {
      str.Remove(0, strlen(prefix));
    }
  }
}
 
 
std::string BasenameOfBranch (const std::string& fullname)
{
  std::string s = fullname;
  size_t pos = s.rfind('.');
  if (pos != std::string::npos) {
    s = s.substr(pos+1);
  }
  while ((pos = s.rfind('[')) != std::string::npos) {
    s.resize(pos);
  }
  return s;
}
 
 
TStreamerInfo* GetStreamerInfoFromFile (const TClass* cl, const TBranch* br)
{
  // Find the file holding this branch.
  // (Can't rely on fInfo having being set up yet.)
  TDirectory* dir = br->GetDirectory();
  if (!dir) return 0;
  TFile* file = dir->GetFile();
  if (!file) return 0;
  if (file->GetSeekInfo() == 0) return 0;
 
  // Find the streamerinfo for this class.
  const TList* silist = file->GetStreamerInfoCache();
  TListIter li (silist);
  TStreamerInfo* info;
  while ((info = dynamic_cast<TStreamerInfo*> (li.Next())) != 0) {
    if (strcmp (info->GetName(), cl->GetName()) == 0)
      break;
  }
 
  return info;
}
 
 
bool DoesClassNeedConv (const TClass* cl, const TBranch* br)
{
  if (!cl) return false;
  TStreamerInfo* info = GetStreamerInfoFromFile (cl, br);
  if (!info) return false;
 
  // Does this class have a conversion?
  if (TConverterRegistry::Instance()->GetConverter (cl->GetName(),
                                                    info->GetCheckSum()))
    return true;
 
  // Do any contained classes have a conversion?
  TObjArray* elems = info->GetElements();
  int ndata = elems->GetEntriesFast();
  for (int i = 0; i < ndata; ++i) {
    TStreamerElement* elt =
      reinterpret_cast<TStreamerElement*> (elems->At (i));
    TClass* bcl = elt->GetClass();
    // Note: we can have bcl==cl for a STL container.
    // For example, the TStreamerInfo for vector<int> has a single
    // TStreamerSTL element with a class that points
    // back to vector<int>.
    if (bcl && bcl != cl && DoesClassNeedConv (bcl, br))
      return true;
  }
  return false;
}
 
 
bool BaseHasField1 (TStreamerBase* elt,
                    const TString& name,
                    const TBranch* br)
{
  // Find the TStreamerInfo for the class we're testing.
  TClass* cl = elt->GetClassPointer();
  if (!cl) return false;
  TStreamerInfo* info = GetStreamerInfoFromFile (cl, br);
  if (!info) return false;
 
  // Go through each element looking for the name.
  // Recursively check base classes.
  TObjArray* elems = info->GetElements();
  size_t ndata = elems->GetEntriesFast();
  for (size_t ielt = 0; ielt < ndata; ielt++) {
    TStreamerElement* selt =
      reinterpret_cast<TStreamerElement*> (elems->At(ielt));
    if (TStreamerBase* belt = dynamic_cast<TStreamerBase*> (selt)) {
      if (BaseHasField1 (belt, name, br))
        return true;
    }
    else {
      if (name == selt->GetName())
        return true;
    }
  }
  return false;
}
 
 
bool BaseHasField (TStreamerBase* elt,
                   TString bname,
                   const TString& namedot,
                   const TBranch* br)
{
  if (!elt) return false;
  RemovePrefix (bname, namedot.Data());
  Ssiz_t i = bname.Index ("[");
  if (i != kNPOS)
    bname.Remove (i);
  i = bname.Index (".");
  if (i != kNPOS)
    bname.Remove (i);
  return BaseHasField1 (elt, bname, br);
}
 
 
   struct R__PushCache {
      TBufferFile &fBuffer;
      TVirtualArray *fOnfileObject;
 
      R__PushCache(TBufferFile &b, TVirtualArray *in, UInt_t size) : fBuffer(b), fOnfileObject(in) {
         if (fOnfileObject) {
            fOnfileObject->SetSize(size);
            fBuffer.PushDataCache( fOnfileObject );
         }
      }
      ~R__PushCache() {
         if (fOnfileObject) fBuffer.PopDataCache();
      }
   };
 
 
} // anonymous namespace
 
 
TConvertingBranchElement::TConvertingBranchElement()
: fConv(0)
, fConvClass(0)
, fConvObject(0)
, fConvOrigBranches(0)
, fConvOrigType(-1)
, fConvContainerFlag(false)
, fConvDontReset(false)
{
}
 
 
TConvertingBranchElement::~TConvertingBranchElement()
{
  // If we made a temporary object instance for conversions, delete it.
  if (fConv && fConvObject)
    fConv->DeletePersObj (fConvObject);
 
  // If we contain dummy branches, delete them here.
  // In that case, we should also delete the saved original branch list.
  if (fConvOrigBranches) {
    Int_t nbranches = fBranches.GetEntriesFast();
    for (Int_t i = 0; i < nbranches; i++) {
      if (fBranches[i]->TestBit (kIsDummy))
        delete fBranches[i];
    }
    fBranches = *fConvOrigBranches;
    delete fConvOrigBranches;
  }
 
  // If we're a dummy ourselves, we should delete the branch list.
  if (TestBit (kIsDummy))
    fBranches.Clear();
  
  // Try to delete the object, if requested.
  if (fgDoDel)
    TConvertingBranchElement::ResetAddress();
}
 
 
void TConvertingBranchElement::Initialize()
{
#if 0
  static bool initialized = false;
  if (initialized)
    return;
  initialized = true;
 
  TClass* cl = gROOT->GetClass ("TBranchElement", true);
  if (!cl) {
    ::Error ("TConvertingBranchElement",
             "Can't find TClass for TBranchElement");
    return;
  }
 
  // Change the @c New() method for @c TBranchElement to make
  // an instance of this class instead.
  cl->SetNew (TConvertingBranchElement::new_TConvertingBranchElement);
#endif
}
 
 
void* TConvertingBranchElement::new_TConvertingBranchElement (void *p)
{
  if (p)
    return new (p) TConvertingBranchElement;
  return new TConvertingBranchElement;
}
 
 
void TConvertingBranchElement::BuildConvertedElisions()
{
  // Can't do anything if we can't find the @c TStreamerInfo.
  if (!fInfo) return;
 
  // The class of this branch's element.
  TClass* topclass = 0;
  if (fID < 0)
    topclass = gROOT->GetClass (GetClassName());
  else {
    std::string s = BasenameOfBranch (GetName());
    int offset = 0;
    TStreamerElement* elt = fInfo->GetStreamerElement(s.c_str(), offset);
    if (elt)
      topclass = elt->GetClass();
  }
  if (!topclass) return;
 
  // Here's the plan.
  // We start by adding all branches to the @c branches list.
  // Then we walk through the members of this class (using the
  // @c TStreamerInfo).
  // If this member is contained in the branch list, then we
  // remove it from @c branches and add it to @c noconv_branches
  // (it wasn't elided).
  // If it's not in the branch list, then it was elided.
  // We look then to see if the corresponding class (or anything
  // it contains) requires a conversion.  If so, then we build
  // a dummy node for it, and add the dummy to @c conv_dummies.
  // We then look through @c branches, find any that actually
  // belong to the new dummy node, remove them from @c branches,
  // and add them to the dummy.
  // If no conversion is needed, then we don't need to do anything
  // at this point.
  //
  // When we're done scanning all the members of the class, we take
  // anything remaining in @c branches and move to @c noconv_branches
  // (these correspond to branches with elided nodes, but with
  // no conversions required.)  Then, if we made any dummy nodes,
  // then we replace our branch list with the concatenation of the
  // dummy list and the @c noconv_branches list (saving the original
  // branch list so that we can restore it later, if needed).
  std::vector<TBranch*> conv_dummies;
  std::vector<TBranch*> noconv_branches;
  std::vector<TBranch*> branches;
 
  // To start with, add all our child branches to @c branches.
  Int_t nbranches = fBranches.GetEntriesFast();
  branches.reserve (nbranches);
  for (Int_t i=0; i < nbranches; i++) {
    TBranch* b = dynamic_cast<TBranchElement*> (fBranches[i]);
    if (b)
      branches.push_back (b);
  }
 
  // Get the @c TStreamerInfo for this class.
  // If this class is a container, then we actually want
  // to get the @c TStreamerInfo for the contained class.
  TStreamerInfo* info = GetStreamerInfoFromFile (topclass, this);
  if (!info && fType == 4) {
    TVirtualCollectionProxy* proxy = topclass->GetCollectionProxy();
    if (!proxy) return;
    topclass = proxy->GetValueClass();
    if (!topclass) return;
    info = GetStreamerInfoFromFile (topclass, this);
  }
  else if (fType == 3) {
    topclass = gROOT->GetClass (fClonesName);
    if (!topclass) return;
    info = GetStreamerInfoFromFile (topclass, this);
  }
  if (!info) return;
 
  // Now walk through all elements in the @c TStreamerInfo.
  TObjArray* elems = info->GetElements();
  size_t ndata = elems->GetEntriesFast();
  for (size_t ielt = 0; ielt < ndata; ++ielt) {
    // The element.
    TStreamerElement* elt =
      reinterpret_cast<TStreamerElement*> (elems->At(ielt));
 
    // See if there's a branch corresponding to this element.
    // If so, add it to the noconv list.
    bool found = false;
    for (unsigned i=0; i < branches.size(); i++) {
      TBranchElement* b = dynamic_cast<TBranchElement*>(branches[i]);
 
      // Test branch @b to see if corresponds to the SI element @ elt.
      if (b && gROOT->GetClass (b->GetClassName()) == topclass) {
        if (dynamic_cast<TStreamerBase*> (elt) != 0 && b->GetType() == 1) {
          // For a base class, the test above is sufficient.
          found = true;
        }
        else {
          // Test the name.
          std::string s = BasenameOfBranch (b->GetName());
          if (s == elt->GetName())
            found = true;
        }
 
        if (found) {
          // We found a branch matching the element.
          // Move the branch from @c branches to @c noconv_branches,
          // and exit the loop over branches.
          noconv_branches.push_back (b);
          branches.erase (branches.begin()+i);
          break;
        }
      }
    }
 
    if (!found) {
      // We didn't find a branch corresponding to this element.
      // Maybe this is an elided class.
      // If this is a class type, then see if it or anything
      // it contains has a conversion.  If so, then build a dummy
      // node for it.
      TClass* cl = elt->GetClass();
      if (cl && DoesClassNeedConv (cl, this)) {
        // It needs a conversion.  Make a dummy node.
        TClass* clparent = gROOT->GetClass (info->GetName());
        TConvertingBranchElement* dum = new TConvertingBranchElement;
        dum->SetBit (kIsDummy);
        TString name;
        if (fID < 0)
          name = elt->GetName();
        else {
          name = GetName();
          if (fType == 1) {
            Ssiz_t i = name.Length()-1;
            while (i >= 0 && name[i] != '.')
              --i;
            name.Remove (i+1);
          }
          else
            name += ".";
          name += elt->GetName();
        }
        dum->SetName (name);
        dum->SetTitle (name);
        TString namedot = name + ".";
        dum->SetParentClass (clparent);
        dum->SetClassName (info->GetName());
        dum->fCheckSum = info->GetCheckSum();
        dum->fClassVersion = topclass->GetClassVersion();
        dum->fID = ielt;
        dum->fTree = this->fTree;
        dum->fDirectory = this->fDirectory;
        dum->fBranchClass = topclass;
        if (dynamic_cast<TStreamerBase*> (elt) != 0) {
          dum->fType = 1;
          Ssiz_t i = namedot.Length()-2;
          while (i >= 0 && namedot[i] != '.')
            --i;
          namedot.Remove (i+1);
        }
        else
          dum->fType = 2;
 
        // Add the dummy node to @c conv_dummies.
        conv_dummies.push_back (dum);
        
        // Find all branches that are a part of this class and
        // move them from @c branches to the dummy node
        for (unsigned i=0; i < branches.size(); i++) {
          TString bname = branches[i]->GetName();
          if (bname.Index (namedot) == 0 &&
              (dum->fType == 2 ||
               BaseHasField (dynamic_cast<TStreamerBase*>(elt),
                             bname,
                             namedot,
                             this)))
          {
            dum->GetListOfBranches()->Add (branches[i]);
            if (TConvertingBranchElement* be =
                dynamic_cast<TConvertingBranchElement*> (branches[i]))
            {
              be->fParentClass = cl;
            }
            branches.erase (branches.begin()+i);
            --i;
          }
        }
      }
    }
    // End of loop over elements.
  }
 
  // Any remaining branches go to @c noconv_branches.
  for (unsigned int i=0; i < branches.size(); i++)
    noconv_branches.push_back (branches[i]);
 
  if (conv_dummies.size() > 0) {
    // We made some dummies.
    // Replace our branch list with the concatenation
    // of the dummy list (@c conv_dummies) and the branches
    // that don't need special processing (@c noconv_branches --- because
    // they either did not have an elision or they didn't require
    // a conversion).
    fConvOrigBranches = new TObjArray;
    *fConvOrigBranches = fBranches;
    fBranches.Clear();
    for (unsigned int i=0; i < conv_dummies.size(); i++)
      fBranches.Add (conv_dummies[i]);
    for (unsigned int i=0; i < noconv_branches.size(); i++)
      fBranches.Add (noconv_branches[i]);
  }
}
 
 
void TConvertingBranchElement::CheckForConversion()
{
  // Need @c TStreamerInfo in order to do anything.
  if (!fInfo) return;
 
  // Restore any elided tree nodes if there's a conversion.
  BuildConvertedElisions();
 
  // See if this element is a class.
  const char* classname = 0;
  int checksum = 0;
 
  if (fID < 0) {
    // Special case for top-level branch.
    classname = GetClassName();
    checksum = fCheckSum;
  }
  else {
    // Otherwise, we need to look at the streamerinfo element.
    std::string s = BasenameOfBranch (GetName());
    int offset = 0;
    TStreamerElement* elt = fInfo->GetStreamerElement(s.c_str(), offset);
    if (elt) {
      TClass* cl = elt->GetClass();
      if (cl) {
        classname = cl->GetName();
        TStreamerInfo* info = GetStreamerInfoFromFile (cl, this);
        if (info)
          checksum = info->GetCheckSum();
      }
    }
  }
 
  if (classname) {
    // Ok, this branch represents a class.
    // See if there's a conversion for it.
    TVirtualConverter* conv =
      TConverterRegistry::Instance()->GetConverter (classname, checksum);
 
    // If there's not a conversion and this class is a container,
    // then we need to see if something in the container needs a conversion.
    if (!conv && (fType == 4 || fType == 3)) {
      // Find the contained class.
      TClass* contclass = gROOT->GetClass (fClonesName.Data());
      if (contclass) {
        TStreamerInfo* info = GetStreamerInfoFromFile (contclass, this);
        if (info) {
          // Found the contained class with its @c TStreamerInfo.
          // See if the contained class has a conversion.
          conv =
            TConverterRegistry::Instance()->GetConverter (fClonesName.Data(),
                                                          info->GetCheckSum());
 
          // If the contained class, or anything it contains, has a conversion,
          // then we need to deal with conversions when reading this container.
          if (conv || DoesClassNeedConv (contclass, this)) {
            fConvContainerFlag = true;
            ConvResetType();
          }
        }
      }
    }
 
    if (conv) {
      TClass* convclass = conv->GetPersClass();
      if (convclass) {
        // We have a conversion!  Remember the converter and persistent
        // class, and create the temporary persistent class instance.
        fConv = conv;
        fConvClass = convclass;
        fConvObject = (char*)conv->NewPersObj();
      }
    }
  }
 
  // Now see if the class containing this element has a conversion.
  if (fID > -1) {
    TVirtualConverter* conv =
      TConverterRegistry::Instance()->GetConverter (GetClassName(),
                                                    fCheckSum);
    if (conv) {
      TClass* convclass = conv->GetPersClass();
      if (convclass) {
        // The class containing this class has a conversion.
        // Change the @c TStreamerInfo to correspond to the
        // appropriate persistent class; also change the parent class
        // pointer.
        Bool_t optim = TStreamerInfo::CanOptimize();
        TStreamerInfo::Optimize(kFALSE);
        TStreamerInfo* info =
          dynamic_cast<TStreamerInfo*> (convclass->GetStreamerInfo (0));
        if (info)
          fInfo = info;
        TStreamerInfo::Optimize(optim);
        fParentClass = convclass;
      }
    }
  }
}
 
 
void TConvertingBranchElement::InitInfo()
{
  // Do the standard stuff.
  TBranchElement::InitInfo();
 
  //  Check for a conversion.
  if (fInfo) {
    const_cast<TConvertingBranchElement*>(this)->CheckForConversion();
 
    // Re-find the fID.
    const_cast<TConvertingBranchElement*>(this)->fInit = kFALSE;
    TBranchElement::InitInfo();
  }
 
  // Change ReadLeaves implementation if needed.
  // The base class implementation works here except for the case
  // of an STL associative container.  We need to change the code
  // for that to notice @c fConvDontReset and to use @c ReadSubBranches.
  if (fType == 4)
    fReadLeaves = (ReadLeaves_t)&TConvertingBranchElement::ReadLeavesCollectionConverting;
  else if (fType == 2 && (fConvOrigType == 41 || fConvOrigType == 31))
    fReadLeaves = (ReadLeaves_t)&TConvertingBranchElement::ReadLeavesMemberBranchCountConverting;
}
 
 
void TConvertingBranchElement::ConvResetType()
{
  Int_t nbranches = fBranches.GetEntriesFast();
  for (Int_t i=0; i < nbranches; i++) {
    TConvertingBranchElement* b =
      dynamic_cast<TConvertingBranchElement*> (fBranches[i]);
    if (b) {
      if (b->fType == 41 || b->fType == 31) {
        b->fConvOrigType = b->fType;
        b->fType = 2;
      }
      b->ConvResetType();
    }
  }
}
 
 
Int_t TConvertingBranchElement::GetEntry(Long64_t entry, Int_t getall)
{
  // The first part of this just copies the base class @c GetEntry.
  // Differences from the base class implementation will be pointed out below.
 
  // Remember which entry we are reading.
  fReadEntry = entry;
 
  // If our tree has a branch ref, make it remember the entry and
  // this branch.  This allows a TRef::GetObject() call done during
  // the following I/O operation, for example in a custom streamer,
  // to search for the referenced object in the proper element of the
  // proper branch.
  TBranchRef* bref = fTree->GetBranchRef();
  if (bref) {
    bref->SetParent(this, fBranchID);
    bref->SetRequestedEntry(entry);
  }
 
  Int_t nbytes = 0;
 
  SetupAddresses();
 
  Int_t nbranches = fBranches.GetEntriesFast();
  if (nbranches) {
    // -- Branch has daughters.
    // One must always read the branch counter.
    // In the case when one reads consecutively twice the same entry,
    // the user may have cleared the TClonesArray between the GetEntry calls.
    if ((fType == 3) || (fType == 4)) {
      Int_t nb = TBranch::GetEntry(entry, getall);
      if (nb < 0) {
        return nb;
      }
      nbytes += nb;
    }
 
    // Here's a difference from the @c TBranchElement base class.
    // First, we need to pick up the current state of the
    // @c fConvDontReset flag (and clear it in the process).
    // Instead of looping over branches here, we factor out
    // that part into @c ReadSubBranches.
    bool dont_reset = fConvDontReset;
    fConvDontReset = false;
    switch(fSTLtype) {
    case TClassEdit::kSet:
    case TClassEdit::kMultiSet:
    case TClassEdit::kMap:
    case TClassEdit::kMultiMap:
      break;
    default:
      // Read non-container composite and list/vector.
      // Associative containers will get entirely read
      // within the @c GetEntry call above (when it calls @c ReadLeaves).
      nbytes += ReadSubBranches (entry, getall, dont_reset);
      break;
    }
  }
  else {
    // -- Terminal branch.
    // Difference from base implementation: pick up the dont_reset flag here.
    bool dont_reset = fConvDontReset;
    fConvDontReset = false;
 
    if (fBranchCount && (fBranchCount->GetReadEntry() != entry)) {
      Int_t nb = fBranchCount->TBranch::GetEntry(entry, getall);
      if (nb < 0) {
        return nb;
      }
      nbytes += nb;
    }
    Int_t nb = 0;
 
    // The base implementation just calls @c TBranch::GetEntry here.
    // But we need to pay attention to the dont_reset flag.
    // If it's set, we can't call @c TBranch::GetEntry (because
    // that would reset the buffer pointer back to the
    // beginning of the container).  Instead, we pick up the
    // buffer pointer and call @c ReadLeaves `by hand'.
    if (dont_reset) {
      TBasket* basket = (TBasket*)GetBasket(GetReadBasket());
      TBuffer* buffer = basket->GetBufferRef();
      Int_t bufbegin = buffer->Length();
 
      // Suppress false positive seen with gcc.
#if __GNUC__ >= 11 && __GNUC__ <= 13
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
      (this->*fReadLeaves) (*buffer);
#if __GNUC__ >= 11 && __GNUC__ <= 13
# pragma GCC diagnostic pop
#endif
 
      nb = buffer->Length() - bufbegin;
    }
    else
      nb = TBranch::GetEntry (entry, getall);
 
    // Rest is the same as the base implementation.
    if (nb < 0) {
      return nb;
    }
    nbytes += nb;
  }
  
  if (fTree->Debug() > 0) {
    if ((entry >= fTree->GetDebugMin()) && (entry <= fTree->GetDebugMax())) {
      Info("GetEntry", "%lld, branch=%s, nbytes=%d", entry, GetName(), nbytes);
    }
  }
  return nbytes;
}
 
 
void TConvertingBranchElement::ReadLeavesCollectionConverting(TBuffer& b)
{
   // -- Read leaves into i/o buffers for this branch.
   // Case of a collection (fType == 4).
   
   ValidateAddress();
   if (fObject == 0)
   {
      // We have nowhere to copy the data (probably because the data member was
      // 'dropped' from the current schema) so let's no copy it in a random place.
      return;
   }
   
   // STL container master branch (has only the number of elements).
   Int_t n;
   b >> n;
   if ((n < 0) || (n > fMaximum)) {
      if (IsMissingCollection()) {
         n = 0;
         b.SetBufferOffset(b.Length()-sizeof(n));
      } else {
         Error("ReadLeaves", "Incorrect size read for the container in %s\n\tThe size read is %d while the maximum is %d\n\tThe size is reset to 0 for this entry (%lld)", GetName(), n, fMaximum, GetReadEntry());
         n = 0;
      }
   }
   fNdata = n;
 
   R__PushCache onfileObject(((TBufferFile&)b),fOnfileObject,n);   
 
   if (!fObject) {
      return;
   }
   // Note: Proxy-helper needs to "embrace" the entire
   //       streaming of this STL container if the container
   //       is a set/multiset/map/multimap (what we do not
   //       know here).
   //       For vector/list/deque Allocate == Resize
   //                         and Commit   == noop.
   // TODO: Exception safety a la TPushPop
   TVirtualCollectionProxy* proxy = GetCollectionProxy();
   TVirtualCollectionProxy::TPushPop helper(proxy, fObject);
   void* alternate = proxy->Allocate(fNdata, true);
   if(fSTLtype != TClassEdit::kVector && proxy->HasPointers() && fSplitLevel > TTree::kSplitCollectionOfPointers ) {
      fPtrIterators->CreateIterators(alternate, proxy);
   } else {
      fIterators->CreateIterators(alternate, proxy);
   }      
   
   //Int_t nbranches = fBranches.GetEntriesFast();
   switch (fSTLtype) {
      case TClassEdit::kSet:
      case TClassEdit::kMultiSet:
      case TClassEdit::kMap:
      case TClassEdit::kMultiMap:
        {
          // Change for conversions:
          // Use @c ReadSubBranches and obey @c fConvDontReset.
          bool dont_reset = fConvDontReset;
          fConvDontReset = false;
          ReadSubBranches (GetReadEntry(), 1, dont_reset);
        }
        break;
      default:
         break;
   }
   //------------------------------------------------------------------------
   // We have split this stuff, so we need to create the the pointers
   //-----------------------------------------------------------------------
   if( proxy->HasPointers() && fSplitLevel > TTree::kSplitCollectionOfPointers )
   {
      TClass *elClass = proxy->GetValueClass();
      
      //--------------------------------------------------------------------
      // The allocation is done in this strange way because ReadLeaves
      // is being called many times by TTreeFormula!!!
      //--------------------------------------------------------------------
      Int_t i = 0;
      if( !fNdata || *(void**)proxy->At( 0 ) != 0 )
         i = fNdata;
      
      for( ; i < fNdata; ++i )
      {
         void **el = (void**)proxy->At( i );
         // coverity[dereference] since this is a member streaming action by definition the collection contains objects and elClass is not null.
         *el = elClass->New();
      }
   }
   
   proxy->Commit(alternate);   
}
 
 
void TConvertingBranchElement::ReadLeavesMemberBranchCountConverting(TBuffer& b)
{
   // -- Read leaves into i/o buffers for this branch.
   // For split-class branch, base class branch, data member branch, or top-level branch.
   // which do have a branch count and are not a counter.
   
   assert(fStreamerType != TVirtualStreamerInfo::kCounter);
 
   ValidateAddress();
   if (fObject == 0)
   {
      // We have nowhere to copy the data (probably because the data member was
      // 'dropped' from the current schema) so let's no copy it in a random place.
      return;
   }
 
   R__PushCache onfileObject(((TBufferFile&)b),fOnfileObject,1);
   // If not a TClonesArray or STL container master branch
   // or sub-branch and branch inherits from tobject,
   // then register with the buffer so that pointers are
   // handled properly.
   if (TestBit(kBranchObject)) {
      b.ResetMap();
      b.MapObject((TObject*) fObject);
   } else if (TestBit(kBranchAny)) {
      b.ResetMap();
      b.MapObject(fObject, fBranchClass);
   }
   
   fNdata = (Int_t) fBranchCount->GetValue(0, 0);
   TStreamerInfo *info = GetInfo();
   if (!info) {
      return;
   }
   // Since info is not null, fReadActionSequence is not null either.
   //b.ReadSequence(*fReadActionSequence, fObject);
   // FIXME!
   // ReadSequence doesn't work here, since it gets structure offsets
   // from TConfiguration, and those haven't been adjusted to take
   // into account the use of the temporary conversion objects.
   // FIXME!
   std::abort();
   //doesn't work
   //info->ReadBuffer (b, (char**)&fObject, fID);
}
 
 
Int_t TConvertingBranchElement::ReadSubBranches(Long64_t entry,
                                                Int_t getall,
                                                bool dont_reset)
{
  Int_t nbytes = 0;
  Int_t nbranches = fBranches.GetEntriesFast();
 
  if (fConvContainerFlag) {
    if (fNdata > 0) {
      // We're reading a container that needs a conversion.
      // We're going to invert the loop order so that we read
      // a single object at a time,
      // Remember the number of entries in the container, but change
      // the number we advertise to 1.
      UInt_t save_ndata = fNdata;
      fNdata = 1;
 
      // Get either the container proxy or the clones array, as appropriate.
      TVirtualCollectionProxy* proxy = 0;
      TClonesArray* clones = 0;
      if (fType == 4)
        proxy = GetCollectionProxy();
      else if (fType == 3)
        clones = (TClonesArray*)fObject;
      else
        abort();
 
      // If we had a proxy, associate it with the container object.
      // This is safe for the case where proxy is null.
      TPushPopSafe helper (proxy,fObject);
 
      // For each element, we may have to call @c SetAddress for each
      // branch.  This is used to avoid doing this repeatedly
      // with the same address (as would happen if we're reading into
      // the temporary persistent object).
      std::vector<char*> last_addrs (nbranches, (char*)0);
 
      // Loop over elements.
      for (UInt_t j = 0; j < save_ndata; j++) {
        // Find the address of the element we want to initialize.
        // How we do this depends on whether we have a @c TClonesArray
        // or a proxy.
        char* addr = 0;
        if (proxy)
          addr = (char*)(proxy->At(j));
        else {
          if (!clones) std::abort();
          addr = (char*)((*clones)[j]);
        }
 
        // The address of the object we want to read.
        // If we have a conversion on the class contained directly
        // in the container, then this will be the temporary persistent
        // object.  Otherwise, it will be the address we found in the
        // last line.
        char* obj = fConvObject ? fConvObject : addr;
 
        // Loop over branches for a single object.
        for (Int_t i = 0; i < nbranches; ++i) {
          TBranch* branch = (TBranch*) fBranches[i];
 
          // If this isn't the first element in the container,
          // then we'll need to set the dont_reset flag.
          if (j > 0) {
            TConvertingBranchElement* be =
              dynamic_cast<TConvertingBranchElement*>(branch);
            if (be)
              be->fConvDontReset = true;
          }
 
          // Find the address for this member,
          char* this_addr = obj + fBranchOffset[i];
 
          // Call @c SetAddress if it's different from the last one we set.
          if (this_addr != last_addrs[i]) {
            last_addrs[i] = this_addr;
            branch->SetAddress (obj + fBranchOffset[i]);
          }
 
          // Read the branch.
          Int_t nb = branch->GetEntry(entry, getall);
 
          // Bookkeeping.
          if (nb < 0) {
            return nb;
          }
          nbytes += nb;
        }
 
        // End of loop over branches.
        // We just read one complete object.
        // Call the converter, if needed.
        if (fConv)
          fConv->ConvertVoid (addr, obj);
      }
 
      // End of loop over entries.  Restore @c fNdata.
      fNdata = save_ndata;
    }
  }
  else {
    // Non-container case.
    // We're reading a single object.
    // Loop over branches.
    for (Int_t i = 0; i < nbranches; ++i) {
      TBranch* branch = (TBranch*) fBranches[i];
 
      // If @c dont_reset is set, we need to propagate it to our children.
      if (dont_reset) {
        TConvertingBranchElement* be =
          dynamic_cast<TConvertingBranchElement*>(branch);
        if (!be) return -1;
        be->fConvDontReset = true;
      }
 
      // Read the branch.
      Int_t nb = branch->GetEntry(entry, getall);
 
      // Bookkeeping.
      if (nb < 0) {
        return nb;
      }
      nbytes += nb;
    }
 
    // Done reading the object.  Call the converter if needed.
    if (fConv)
      fConv->ConvertVoid (fObject, fConvObject);
  }
  return nbytes;
}
 
 
void TConvertingBranchElement::Streamer(TBuffer& R__b)
{
  TObjArray brsave;
  Int_t type_save = 0;
 
  if (!R__b.IsReading()) {
    if (fConvOrigType == -1)
      fConvOrigType = fType;
 
    type_save = fType;
    fType = fConvOrigType;
    if (fConvOrigBranches) {
      brsave = fBranches;
      fBranches = *fConvOrigBranches;
    }
  }
 
  TBranchElement::Streamer (R__b);
 
  if (!R__b.IsReading()) {
    fType = type_save;
    if (fConvOrigBranches) {
      fBranches = brsave;
    }
  }
}
 
 
 
void TConvertingBranchElement::InitializeOffsets()
{
  // previously in InitializeOffsets, after:
  //  if (fType == 1) {
  //    pClass = branchElem->GetClassPointer();
  //  } else {
  //    pClass = subBranch->GetParentClass();
  //  }
  //
  // i had:
  //
  //  if (fConvClass) pClass = fConvClass;
  //
  // This is a hack so we don't need to modify the base class
  // InitializeOffsets.
  //
  TStreamerElement* branchElem = 0;
  TClass* cl_orig = 0;
  if (fConvClass && fID > -1) {
    TStreamerInfo* si = GetInfo();
    branchElem = si->GetElem(fID);
    if (branchElem) {
      if (branchElem && branchElem->IsBase()) {
        cl_orig = branchElem->GetClassPointer();
        branchElem->Update (cl_orig, fConvClass);
      }
      else
        branchElem = 0;
    }
  }
 
  if (fConvClass) {
    Int_t nbranches = fBranches.GetEntriesFast();
    for (Int_t subBranchIdx = 0; subBranchIdx < nbranches; ++subBranchIdx) {
      TConvertingBranchElement* br = 
        dynamic_cast<TConvertingBranchElement*> (fBranches[subBranchIdx]);
      if (br) {
        br->fParentClass = fConvClass;
      }
    }
  }
 
  TBranchElement::InitializeOffsets();
 
  if (branchElem)
    branchElem->Update (fConvClass, cl_orig);
}
 
 
void TConvertingBranchElement::SetAddress(void* add)
{
   TBranchElement::SetAddress (add);
   if (fConvObject) {
     Int_t nbranches = fBranches.GetEntriesFast();
     for (Int_t i = 0; i < nbranches; ++i) {
       TBranch* abranch = (TBranch*) fBranches[i];
       abranch->SetAddress(fConvObject + fBranchOffset[i]);
     }
   }
}
 
 
 
void TConvertingBranchElement_init()
{
  TConvertingBranchElement::Initialize();
}
 
 
void TConvertingBranchElement::ResetAddress()
{
  char* object = fObject;
  char* address = fAddress;
  TBranchElement::ResetAddress();
 
  if (fgDoDel) {
    fObject = object;
    fAddress = address;
 
    // This is copied from the disabled code of TBranchElement::ReleaseObject.
    if (fID < 0) {
      // -- We are a top-level branch.
      if (fAddress && (*((char**) fAddress) != fObject)) {
        // The semantics of fAddress and fObject are violated.
        // Assume the user changed the pointer on us.
        if (TestBit(kDeleteObject)) {
          Warning("ReleaseObject", "branch: %s, You have overwritten the pointer to an object which I owned!", GetName());
          Warning("ReleaseObject", "This is a memory leak.  Please use SetAddress() to change the pointer instead.");
          ResetBit(kDeleteObject);
        }
      }
    }
 
    // Delete any object we may have allocated during a call to SetAddress.
    // (sss - added fAddress check to fix coverity warning)
    if (fAddress && fObject && TestBit(kDeleteObject)) {
      ResetBit(kDeleteObject);
      if (fType == 3) {
        // -- We are a TClonesArray master branch.
        TClonesArray::Class()->Destructor(fObject);
        fObject = 0;
        if ((fStreamerType == TVirtualStreamerInfo::kObjectp) ||
            (fStreamerType == TVirtualStreamerInfo::kObjectP)) {
          // -- We are a pointer to a TClonesArray.
          // We must zero the pointer in the object.
          *((char**) fAddress) = 0;
        }
      } else if (fType == 4) {
        // -- We are an STL container master branch.
        TVirtualCollectionProxy* proxy = GetCollectionProxy();
        if (!proxy) {
          Warning("ResetAddress", "Cannot delete allocated STL container because I do not have a proxy!  branch: %s", GetName());
          fObject = 0;
        } else {
          proxy->Destructor(fObject);
          fObject = 0;
        }
        if (fStreamerType == TVirtualStreamerInfo::kSTLp) {
          // -- We are a pointer to an STL container.
          // We must zero the pointer in the object.
          *((char**) fAddress) = 0;
        }
      } else {
        // We are *not* a TClonesArray master branch and we are *not* an STL container master branch.
        TClass* cl = fBranchClass.GetClass();
        if (!cl) {
          Warning("ResetAddress", "Cannot delete allocated object because I cannot instantiate a TClass object for its class!  branch: '%s' class: '%s'", GetName(), fBranchClass.GetClassName());
          fObject = 0;
        } else {
          cl->Destructor(fObject);
          fObject = 0;
        }
      }
    }
 
    fObject = 0;
    fAddress = 0;
  }
}
 
 
void TConvertingBranchElement::SetDoDel (bool flag)
{
  fgDoDel = flag;
}