RootDataConnection.h

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/***********************************************************************************\
* (c) Copyright 1998-2026 CERN for the benefit of the LHCb and ATLAS collaborations *
*                                                                                   *
* This software is distributed under the terms of the Apache version 2 licence,     *
* copied verbatim in the file "LICENSE".                                            *
*                                                                                   *
* In applying this licence, CERN does not waive the privileges and immunities       *
* granted to it by virtue of its status as an Intergovernmental Organization        *
* or submit itself to any jurisdiction.                                             *
\***********************************************************************************/
#pragma once
 
// Framework include files
#include <Gaudi/Property.h>
#include <GaudiKernel/ClassID.h>
#include <GaudiKernel/IIncidentSvc.h>
#include <GaudiKernel/SmartIF.h>
#include <GaudiUtils/IIODataManager.h>
#include <map>
#include <set>
#include <string>
#include <string_view>
#include <vector>
 
#include <RootCnv/RootRefs.h>
#include <TFile.h>
#include <TTreePerfStats.h>
 
// Forward declarations
class TTree;
class TClass;
class TBranch;
 
class MsgStream;
class IRegistry;
class DataObject;
class IIncidentSvc;
 
/*
 *  Gaudi namespace declaration
 */
namespace Gaudi {

  class GAUDI_API RootConnectionSetup final {
  private:
    std::unique_ptr<MsgStream> m_msgSvc;
    SmartIF<IIncidentSvc> m_incidentSvc = nullptr;
 
  public:
    typedef std::vector<std::string> StringVec;

    StringVec cacheBranches;
    StringVec vetoBranches;
    std::string loadSection;
    int cacheSize{ 0 };
    int learnEntries{ 0 };
 
    Gaudi::Property<bool> produceReproducibleFiles{ "ProduceReproducibleFiles", true,
                                                    "configure output files to be more reproducible" };
 
    Gaudi::Property<bool> root630ForwardCompatibility{
        "ROOT630ForwardCompatibility", false,
        "When opening a file for CREATE or RECREATE, enable ROOT 6.30 forward compatibility "
        "(i.e. write a file that is readable with ROOT 6.24). Requires ROOT >= 6.30.06, see "
        "<https://github.com/root-project/root/issues/14793>." };

    RootConnectionSetup() = default;

    static StatusCode setCompression( std::string_view compression );
    static int compression();

    void setMessageSvc( MsgStream* m );
    MsgStream& msgSvc() const { return *m_msgSvc; }

    void setIncidentSvc( IIncidentSvc* m );
    IIncidentSvc* incidentSvc() const { return m_incidentSvc.get(); }
  };

  class GAUDI_API RootDataConnection : virtual public Gaudi::IDataConnection {
  public:
    enum class Status : StatusCode::code_t { ROOT_READ_ERROR = 0x2, ROOT_OPEN_ERROR = 0x4 };

    struct ContainerSection {
      ContainerSection() : start( -1 ), length( 0 ) {}
      ContainerSection( int s, int l ) : start( s ), length( l ) {}
      ContainerSection( const ContainerSection& s ) : start( s.start ), length( s.length ) {}
      ContainerSection& operator=( const ContainerSection& s ) {
        if ( this != &s ) {
          start  = s.start;
          length = s.length;
        }
        return *this;
      }

      int start;
      int length;
    };

    typedef std::vector<std::string> StringVec;
    typedef std::vector<std::pair<std::string, std::string>> ParamMap;
    typedef std::map<std::string, TTree*, std::less<>> Sections;
    typedef std::vector<ContainerSection> ContainerSections;
    typedef std::map<std::string, ContainerSections, std::less<>> MergeSections;
    typedef std::vector<RootRef> LinkSections;
    typedef std::set<const IInterface*> Clients;

    MsgStream&    msgSvc() const { return m_setup->msgSvc(); }
    IIncidentSvc* incidentSvc() const { return m_setup->incidentSvc(); }
 
  protected:
    std::shared_ptr<RootConnectionSetup> m_setup;
    std::unique_ptr<TTreePerfStats> m_statistics;
    std::unique_ptr<TFile> m_file;
    TTree* m_refs = nullptr;
    Sections m_sections;
    StringVec m_dbs;
    StringVec m_conts;
    StringVec m_links;
    StringVec m_mergeFIDs;
    ParamMap m_params;
    MergeSections m_mergeSects;
    LinkSections m_linkSects;
    Clients m_clients;
    std::string m_empty;

    const std::string& empty() const;

    StatusCode saveRefs();
 
  public:
    class Tool {
    protected:
      typedef RootDataConnection::StringVec         StringVec;
      typedef RootDataConnection::ParamMap          ParamMap;
      typedef RootDataConnection::Sections          Sections;
      typedef RootDataConnection::MergeSections     MergeSections;
      typedef RootDataConnection::LinkSections      LinkSections;
      typedef RootDataConnection::ContainerSection  ContainerSection;
      typedef RootDataConnection::ContainerSections ContainerSections;

      RootDataConnection* c;
 
    public:
      TTree*             refs() const { return c->m_refs; }
      StringVec&         dbs() const { return c->m_dbs; }
      StringVec&         conts() const { return c->m_conts; }
      StringVec&         links() const { return c->m_links; }
      ParamMap&          params() const { return c->m_params; }
      MsgStream&         msgSvc() const { return c->msgSvc(); }
      IIncidentSvc*      incidentSvc() const { return c->incidentSvc(); }
      const std::string& name() const { return c->m_name; }
      Sections&          sections() const { return c->m_sections; }
      LinkSections&      linkSections() const { return c->m_linkSects; }
      MergeSections&     mergeSections() const { return c->m_mergeSects; }

      virtual ~Tool() = default;
      virtual TBranch* getBranch( std::string_view section, std::string_view n ) = 0;

      virtual StatusCode readRefs() = 0;
      virtual StatusCode saveRefs() = 0;
      virtual int loadRefs( std::string_view section, std::string_view cnt, unsigned long entry,
                            RootObjectRefs& refs ) = 0;
    };
    std::unique_ptr<Tool> m_tool;
    friend class Tool;

    Tool* makeTool();
 
  public:
    RootDataConnection( const IInterface* own, std::string_view nam, std::shared_ptr<RootConnectionSetup> setup );

    TFile* file() const { return m_file.get(); }
    bool isConnected() const override { return bool( m_file ); }
    bool isWritable() const { return m_file && m_file->IsWritable(); }
    Tool* tool() const { return m_tool.get(); }
    const MergeSections& mergeSections() const { return m_mergeSects; }
    const StringVec& mergeFIDs() const { return m_mergeFIDs; }

    void addClient( const IInterface* client );
    size_t removeClient( const IInterface* client );
    bool lookupClient( const IInterface* client ) const;

    void badWriteError( std::string_view msg ) const;

    std::pair<const RootRef*, const ContainerSection*> getMergeSection( std::string_view container, int entry ) const;

    void enableStatistics( std::string_view section );
    void saveStatistics( std::string_view statisticsFile );

    int loadObj( std::string_view section, std::string_view cnt, unsigned long entry, DataObject*& pObj );

    int loadRefs( std::string_view section, std::string_view cnt, unsigned long entry, RootObjectRefs& refs );

    std::pair<int, unsigned long> saveObj( std::string_view section, std::string_view cnt, TClass* cl, DataObject* pObj,
                                           int minBufferSize, int maxBufferSize, int approxEventsPerBasket,
                                           int split_lvl, bool fill_missing = false );
    std::pair<int, unsigned long> save( std::string_view section, std::string_view cnt, TClass* cl, void* pObj,
                                        int minBufferSize, int maxBufferSize, int approxEventsPerBasket, int split_lvl,
                                        bool fill_missing = false );

    StatusCode connectRead() override;
    StatusCode connectWrite( IoType typ ) override;
    StatusCode disconnect() override;
    StatusCode read( void* const, size_t ) override { return StatusCode::FAILURE; }
    StatusCode write( const void*, int ) override { return StatusCode::FAILURE; }
    long long int seek( long long int, int ) override { return -1; }

    TTree* getSection( std::string_view sect, bool create = false );

    TBranch* getBranch( std::string_view section, std::string_view branch_name ) {
      return m_tool->getBranch( section, branch_name );
    }

    TBranch* getBranch( std::string_view section, std::string_view branch_name, TClass* cl, void* ptr, int buff_siz,
                        int split_lvl );

    void makeRef( const IRegistry& pA, RootRef& ref );
    void makeRef( std::string_view name, long clid, int tech, std::string_view db, std::string_view cnt, int entry,
                  RootRef& ref );

    int makeLink( std::string_view p );

    const std::string& getDb( int which ) const;

    const std::string& getCont( int which ) const {
      return ( which >= 0 ) && ( size_t( which ) < m_conts.size() ) ? *( m_conts.begin() + which ) : empty();
    }

    const std::string& getLink( int which ) const {
      return ( which >= 0 ) && ( size_t( which ) < m_links.size() ) ? *( m_links.begin() + which ) : empty();
    }
  };
} // End namespace Gaudi
 
STATUSCODE_ENUM_DECL( Gaudi::RootDataConnection::Status )