podio::ROOTReader Class Reference

#include <ROOTReader.h>

Inheritance diagram for podio::ROOTReader:

Public Member Functions
	ROOTReader ()=default
	~ROOTReader ()
	ROOTReader (const ROOTReader &)=delete
ROOTReader &	operator= (const ROOTReader &)=delete
void	openFile (const std::string &filename) override
void	openFiles (const std::vector< std::string > &filenames)
void	closeFile () override
void	closeFiles ()
void	readEvent () override
	Read all collections requested.
std::shared_ptr< CollectionIDTable >	getCollectionIDTable () override
	Read CollectionIDTable from ROOT file.
unsigned	getEntries () const override
	Returns number of entries in the TTree.
void	endOfEvent () override
	Preparing to read next event.
void	goToEvent (unsigned evnum) override
	Preparing to read a given event.
podio::version::Version	currentFileVersion () const override
	Get the podio version with which the current file has been written.
bool	isValid () const override
	Check if TFile is valid.
Public Member Functions inherited from podio::IReader
virtual	~IReader ()=default
virtual CollectionBase *	readCollection (const std::string &name)=0
virtual std::shared_ptr< CollectionIDTable >	getCollectionIDTable ()=0
	Get CollectionIDTable of read-in data.
virtual GenericParameters *	readEventMetaData ()=0
	read event meta data from file
virtual std::map< int, GenericParameters > *	readCollectionMetaData ()=0
virtual std::map< int, GenericParameters > *	readRunMetaData ()=0
virtual unsigned	getEntries () const =0
	get the number of events available from this reader
virtual void	endOfEvent ()=0
	Prepare the reader to read the next event.
virtual bool	isValid () const =0
	Check if reader is valid.
virtual void	openFile (const std::string &filename)=0
virtual void	closeFile ()=0
virtual void	readEvent ()=0
virtual void	goToEvent (unsigned iEvent)=0
virtual podio::version::Version	currentFileVersion () const =0
	Get the podio version with which the current file has been written.

Detailed Description

This class has the function to read available data from disk and to prepare collections and buffers.

Definition at line 33 of file ROOTReader.h.

Constructor & Destructor Documentation

ROOTReader() [1/2]

podio::ROOTReader::ROOTReader ( )

default

~ROOTReader()

podio::ROOTReader::~ROOTReader

(

)

Definition at line 20 of file ROOTReader.cc.

                        { // NOLINT(modernize-use-equals-default)
}

ROOTReader() [2/2]

podio::ROOTReader::ROOTReader ( const ROOTReader &  )

delete

Member Function Documentation

closeFile()

void podio::ROOTReader::closeFile ( )

overridevirtual

Implements podio::IReader.

Definition at line 188 of file ROOTReader.cc.

                           {
  closeFiles();
}

closeFiles()

void podio::ROOTReader::closeFiles

(

)

Definition at line 192 of file ROOTReader.cc.

                            {
  delete m_chain;
}

Referenced by closeFile().

currentFileVersion()

podio::version::Version podio::ROOTReader::currentFileVersion ( ) const

inlineoverridevirtual

Get the podio version with which the current file has been written.

Implements podio::IReader.

Definition at line 67 of file ROOTReader.h.

                                                          {
    return m_fileVersion;
  }

endOfEvent()

void podio::ROOTReader::endOfEvent ( )

overridevirtual

Preparing to read next event.

Implements podio::IReader.

Definition at line 212 of file ROOTReader.cc.

                            {
  ++m_eventNumber;
  m_inputs.clear();
}

Referenced by testWithIO().

getCollectionIDTable()

std::shared_ptr< CollectionIDTable > podio::ROOTReader::getCollectionIDTable ( )

inlineoverridevirtual

Read CollectionIDTable from ROOT file.

Implements podio::IReader.

Definition at line 54 of file ROOTReader.h.

                                                                   {
    return m_table;
  }

getEntries()

unsigned podio::ROOTReader::getEntries ( ) const

overridevirtual

Returns number of entries in the TTree.

Implements podio::IReader.

Definition at line 217 of file ROOTReader.cc.

                                      {
  return m_chain->GetEntries();
}

goToEvent()

void podio::ROOTReader::goToEvent ( unsigned  evnum )

overridevirtual

Preparing to read a given event.

Implements podio::IReader.

Definition at line 221 of file ROOTReader.cc.

                                               {
  m_eventNumber = eventNumber;
  m_inputs.clear();
}

isValid()

bool podio::ROOTReader::isValid ( ) const

overridevirtual

Check if TFile is valid.

Implements podio::IReader.

Definition at line 208 of file ROOTReader.cc.

                               {
  return m_chain->GetFile()->IsOpen() && !m_chain->GetFile()->IsZombie();
}

openFile()

void podio::ROOTReader::openFile ( const std::string &  filename )

overridevirtual

Implements podio::IReader.

Definition at line 140 of file ROOTReader.cc.

                                                   {
  openFiles({filename});
}

Referenced by testWithIO().

openFiles()

void podio::ROOTReader::openFiles

(

const std::vector< std::string > &

filenames

)

Definition at line 144 of file ROOTReader.cc.

                                                                {
  m_chain = new TChain("events");
  for (const auto& filename : filenames) {
    //-1 forces the headers to be read so that
    // the validity of the files can be checked
    if (!m_chain->Add(filename.c_str(), -1)) {
      delete m_chain;
      throw std::runtime_error("File " + filename + " couldn't be found");
    }
  }
 
  // read the meta data and build the collectionBranches cache
  // NOTE: This is a small pessimization, if we do not read all collections
  // afterwards, but it makes the handling much easier in general
  auto metadatatree = static_cast<TTree*>(m_chain->GetFile()->Get("metadata"));
  m_table = std::make_shared<podio::CollectionIDTable>();
  auto* table = m_table.get();
  metadatatree->SetBranchAddress("CollectionIDs", &table);
 
  podio::version::Version* versionPtr{nullptr};
  if (auto* versionBranch = root_utils::getBranch(metadatatree, "PodioVersion")) {
    versionBranch->SetAddress(&versionPtr);
  }
 
  // Check if the CollectionTypeInfo branch is there and assume that the file
  // has been written with with podio pre #197 (<0.13.1) if that is not the case
  if (auto* collInfoBranch = root_utils::getBranch(metadatatree, "CollectionTypeInfo")) {
    auto collectionInfo = new std::vector<root_utils::CollectionInfoT>;
    collInfoBranch->SetAddress(&collectionInfo);
    metadatatree->GetEntry(0);
    createCollectionBranches(*collectionInfo);
    delete collectionInfo;
  } else {
    std::cout << "PODIO: Reconstructing CollectionTypeInfo branch from other sources in file: \'"
              << m_chain->GetFile()->GetName() << "\'" << std::endl;
    metadatatree->GetEntry(0);
    const auto collectionInfo = root_utils::reconstructCollectionInfo(m_chain, *m_table);
    createCollectionBranches(collectionInfo);
  }
 
  m_fileVersion = versionPtr ? *versionPtr : podio::version::Version{0, 0, 0};
  delete versionPtr;
}

Referenced by openFile().

operator=()

ROOTReader & podio::ROOTReader::operator= ( const ROOTReader &  )

delete

readEvent()

void podio::ROOTReader::readEvent ( )

overridevirtual

Read all collections requested.

Implements podio::IReader.

Definition at line 196 of file ROOTReader.cc.

                           {
  m_chain->GetEntry(m_eventNumber);
  // first prepare all collections in memory...
  for (auto inputs : m_inputs) {
    inputs.first->prepareAfterRead();
  }
  // ...then clean-up the references between them
  //    for(auto inputs : m_inputs){
  //    inputs.first->setReferences(m_registry);
 
  //  }
}

---

The documentation for this class was generated from the following files:

• ROOTReader.h
• ROOTReader.cc