RootDataProvider.h

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/*
 * RootDataProvider.h
 *
 *  Created on: 24 May 2017
 *      Author: Nicola Mori
 */

#ifndef ROOTDATAPROVIDER_H_
#define ROOTDATAPROVIDER_H_

// EventAnalysis headers
#include "data/DataProvider.h"

// Root headers
#include "TChain.h"
#include "TDataType.h"

class TFile;
class TObject;
class TBranch;
class TClass;

namespace EA {

class RootDataProvider : public DataProvider {
public:
  RootDataProvider(const std::string &name, const std::string &dataSource);

  bool Connect() override;

  bool Disconnect() override;
  RetrievalResult GetObject(const std::string &name, ObjectCategory category, ObjectWrapper &wrapper,
                            std::string &actualName) override;
  bool SetCurrentEvent(unsigned int event, std::vector<std::string> &notValidGlobalObjects) override;

  virtual std::vector<std::string> FreeObjects(const std::vector<std::string> &objs, Memory::Status memStatus) override;

protected:
  observer_ptr<TFile> GetCurrentFile();

  observer_ptr<TChain> GetEventChain() { return _eventChain; }

private:
  struct EvObjInfo {
    void *object; // Input buffer; it is nullptr when the branch address is not set
    TClass *objClass;
    EDataType objDataType;
    TBranch *objectBranch; // Branch for event objects

    // The following will be used only for real names (i.e. not for aliases)
    bool flag;           // True if the object is present for current event
    TBranch *flagBranch; // Branch for flags

    // The following will be non-empty only for aliases
    std::map<std::string, TBranch *> aliasedBranches;

    EvObjInfo()
        : object(nullptr), objClass(nullptr), objectBranch(nullptr), flag(true), flagBranch(nullptr),
          objDataType(kOther_t) {}
  };
  using EvObjectsBook = std::unordered_map<std::string, EvObjInfo>;
  EvObjectsBook _eventBook;

  // Object info structure for standard global objects and for global object aliases
  struct GlobObjInfo {
    // Common fields for standard and for aliases
    TClass *objClass;
    void *object;            // Input buffer for the global object
    std::string *actualName; // Name of the object or currently aliased object

    // The following will be non-empty only for aliases
    TBranch *aliasedBranch; // Branch of names for aliased global objects corresponding to the alias
    std::map<std::string, GlobObjInfo *> aliasedObjects; // Global book entries for aliased objects

    GlobObjInfo() : objClass(nullptr), object(nullptr), actualName(nullptr), aliasedBranch(nullptr) {}
  };
  using GlobObjectsBook = std::unordered_map<std::string, GlobObjInfo>;
  GlobObjectsBook _globalBook;

  TChain *_eventChain;

  unsigned int _currentEvent;
  bool _withoutTree;       // true if we are processing a single Root file with no event tree
  TFile *_fileWoTree;      // Pointer to the single input file if it has no event tree (and thus cannot be obtained from
                           // the chain)
  Long64_t _treeReadEntry; // entry of the current tree which is <= than the chain entry
  Int_t _treeNumber;
};

} // namespace EA

#endif /* ROOTDATAPROVIDER_H_ */