BareRootProductGetter.h

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#ifndef FWLite_BareRootProductGetter_h
#define FWLite_BareRootProductGetter_h
// -*- C++ -*-
//
// Package:     FWLite
// Class  :     BareRootProductGetter
//
//
// Original Author:  Chris Jones
//         Created:  Tue May 23 11:03:27 EDT 2006
//

// user include files
#include "DataFormats/Common/interface/WrapperBase.h"
#include "DataFormats/Common/interface/EDProductGetter.h"
#include "FWCore/FWLite/interface/BranchMapReader.h"
#include "FWCore/Utilities/interface/propagate_const.h"

// system include files
#include "Rtypes.h"
#include <map>
#include <memory>
#include <vector>

// forward declarations
class TBranch;
class TClass;

namespace edm {
  class BranchID;
  class ProductID;
  class ThinnedAssociation;
}  // namespace edm

class BareRootProductGetter : public edm::EDProductGetter {
public:
  BareRootProductGetter();
  ~BareRootProductGetter() override;
  BareRootProductGetter(BareRootProductGetter const&) = delete;                   // stop default
  BareRootProductGetter const& operator=(BareRootProductGetter const&) = delete;  // stop default

  // ---------- const member functions ---------------------
  edm::WrapperBase const* getIt(edm::ProductID const&) const override;

  // getThinnedProduct assumes getIt was already called and failed to find
  // the product. The input key is the index of the desired element in the
  // container identified by ProductID (which cannot be found).
  // If the return value is not null, then the desired element was
  // found in a thinned container. If the desired element is not
  // found, then an optional without a value is returned.
  std::optional<std::tuple<edm::WrapperBase const*, unsigned int>> getThinnedProduct(edm::ProductID const&,
                                                                                     unsigned int key) const override;

  // getThinnedProducts assumes getIt was already called and failed to find
  // the product. The input keys are the indexes into the container identified
  // by ProductID (which cannot be found). On input the WrapperBase pointers
  // must all be set to nullptr (except when the function calls itself
  // recursively where non-null pointers mark already found elements).
  // Thinned containers derived from the product are searched to see
  // if they contain the desired elements. For each that is
  // found, the corresponding WrapperBase pointer is set and the key
  // is modified to be the key into the container where the element
  // was found. The WrapperBase pointers might or might not all point
  // to the same thinned container.
  void getThinnedProducts(edm::ProductID const&,
                          std::vector<edm::WrapperBase const*>& foundContainers,
                          std::vector<unsigned int>& keys) const override;

  // This overload is allowed to be called also without getIt()
  // being called first, but the thinned ProductID must come from an
  // existing RefCore. The input key is the index of the desired
  // element in the container identified by the parent ProductID.
  // If the return value is not null, then the desired element was found
  // in a thinned container. If the desired element is not found, then
  // an optional without a value is returned.
  edm::OptionalThinnedKey getThinnedKeyFrom(edm::ProductID const& parent,
                                            unsigned int key,
                                            edm::ProductID const& thinned) const override;

private:
  // ---------- static member functions --------------------

  // ---------- member functions ---------------------------
  unsigned int transitionIndex_() const override { return 0u; }

  edm::WrapperBase const* getIt(edm::BranchID const&, Long_t eventEntry) const;

  struct Buffer {
    Buffer(edm::WrapperBase const* iProd, TBranch* iBranch, void* iAddress, TClass* iClass)
        : product_(iProd), branch_(iBranch), address_(iAddress), eventEntry_(-1), class_(iClass) {}
    Buffer() : product_(), branch_(), address_(), eventEntry_(-1), class_(nullptr) {}

    std::shared_ptr<edm::WrapperBase const> product_;
    edm::propagate_const<TBranch*> branch_;
    void* address_;      //the address to pass to Root since as of 5.13 they cache that info
    Long_t eventEntry_;  //the event Entry used with the last GetEntry call
    edm::propagate_const<TClass*> class_;
  };

  Buffer* createNewBuffer(edm::BranchID const&) const;
  edm::ThinnedAssociation const* getThinnedAssociation(edm::BranchID const& branchID, Long_t eventEntry) const;

  // ---------- member data --------------------------------

  typedef std::map<edm::BranchID, Buffer> IdToBuffers;
  mutable IdToBuffers idToBuffers_;
  mutable fwlite::BranchMapReader branchMap_;
};
#endif