AthenaRootStreamer Class Reference

This class enhances ROOT custom streamer base TClassStreamer and can choose a converter function based on the streamerinfo checksum. More...

#include <AthenaRootStreamer.h>

Inheritance diagram for AthenaRootStreamer:

Collaboration diagram for AthenaRootStreamer:

Public Member Functions
	AthenaRootStreamer (const std::string &class_name, ::Service *service=0)
	Constructor. More...
virtual	~AthenaRootStreamer ()
	Destructor. More...
StatusCode	AddConverter (std::unique_ptr< AthenaRootConverterHandle > converter)
	Add a converter to this streamer. More...
StatusCode	Adopt ()
	Adopt (enable) this ROOT custom streamer. More...
virtual void	operator() (TBuffer &b, void *obj)
	this operator is colled by ROOT to ready and write objects More...

Protected Member Functions
void	FindVersion (TBuffer *buf, UInt_t *startpos, UInt_t *bcnt)

Static Protected Member Functions
static Version_t	R__FindStreamerInfoVersion (const TClass *cl, UInt_t checksum)

Private Types
typedef std::map< UInt_t, std::unique_ptr< AthenaRootConverterHandle > >	ConverterMap
typedef std::set< UInt_t >	ChecksumSet

Private Attributes
std::string	m_className
TClass *	m_class
UInt_t	m_streamerChecksum
Version_t	m_streamerVersion
TFile *	m_lastFile
ConverterMap	m_converterMap
ChecksumSet	m_seenChecksums
Service *	m_service

Detailed Description

This class enhances ROOT custom streamer base TClassStreamer and can choose a converter function based on the streamerinfo checksum.

Definition at line 32 of file AthenaRootStreamer.h.

Member Typedef Documentation

ChecksumSet

typedef std::set<UInt_t> AthenaRootStreamer::ChecksumSet

private

Definition at line 69 of file AthenaRootStreamer.h.

ConverterMap

typedef std::map<UInt_t, std::unique_ptr<AthenaRootConverterHandle> > AthenaRootStreamer::ConverterMap

private

Definition at line 66 of file AthenaRootStreamer.h.

Constructor & Destructor Documentation

AthenaRootStreamer()

AthenaRootStreamer::AthenaRootStreamer	(	const std::string &	class_name,
		::Service *	service = 0
	)

Constructor.

Parameters

class_name	[IN] name of the class that is stored in the file (in most cases of schema evolution this is the same name as in the dictionary, but it may be different)
service	[IN] pointer to parent service, used to write out messages to log

Definition at line 21 of file AthenaRootStreamer.cxx.

      : m_className(class_name),
        m_class(0),
        m_streamerChecksum (0),
        m_streamerVersion (0),
    m_lastFile(0),
    m_service(service)
{
}

~AthenaRootStreamer()

AthenaRootStreamer::~AthenaRootStreamer ( )

virtual

Destructor.

Definition at line 31 of file AthenaRootStreamer.cxx.

{
}

Member Function Documentation

AddConverter()

StatusCode AthenaRootStreamer::AddConverter

(

std::unique_ptr< AthenaRootConverterHandle >

converter

)

Add a converter to this streamer.

Parameters

converter

[IN] - converter handle holding user defined converter object

Definition at line 36 of file AthenaRootStreamer.cxx.

                                                                                              {
  if (m_converterMap.try_emplace (converter->StreamerChecksum(), std::move(converter)).second) {
    return(StatusCode::SUCCESS);
  }
  return(StatusCode::FAILURE);
}

Adopt()

StatusCode AthenaRootStreamer::Adopt

(

)

Adopt (enable) this ROOT custom streamer.

Definition at line 45 of file AthenaRootStreamer.cxx.

                                     {
   m_class = gROOT->GetClass(m_className.c_str());
   if (m_class == 0) {
      return(StatusCode::FAILURE);
   }
   m_class->AdoptStreamer(this);
   return(StatusCode::SUCCESS);
}

FindVersion()

void AthenaRootStreamer::FindVersion ( TBuffer *  buf, UInt_t *  startpos, UInt_t *  bcnt  )

protected

Definition at line 82 of file AthenaRootStreamer.cxx.

                                                                                 {
   const UInt_t kByteCountMask     = 0x40000000;  // OR the byte count with this
   const Version_t kByteCountVMask = 0x4000;      // OR the version byte count with this
 
   if (startpos && bcnt) {
      // before reading object save start position
      *startpos = buf->Length();
 
      // read byte count (older files don't have byte count)
      // byte count is packed in two individual shorts, this to be
      // backward compatible with old files that have at this location
      // only a single short (i.e. the version)
      union {
         UInt_t     cnt;
         Version_t  vers[2];
      } v;
      v.cnt = 0;  // to prevent Valgrind complaining about uninitialized variable
#ifdef R__BYTESWAP
      *buf >> v.vers[1];
      *buf >> v.vers[0];
#else
      *buf >> v.vers[0];
      *buf >> v.vers[1];
#endif
      if( !(v.cnt & kByteCountMask) ) {
         // no bytecount, go back before reading version
         buf->SetBufferOffset(buf->Length() - sizeof(UInt_t));
         v.cnt = 0;
      }
      *bcnt = (v.cnt & ~kByteCountMask);
      *buf >> m_streamerVersion;
   } else {
      // not interested in byte count
      *buf >> m_streamerVersion;
 
      // if this is a byte count, then skip next short and read version
      if (m_streamerVersion & kByteCountVMask) {
         *buf >> m_streamerVersion;
         *buf >> m_streamerVersion;
      }
   }
   //Version_t objectVersion = m_streamerVersion;
   TFile* fParent = (TFile*)buf->GetParent();
   if (m_lastFile != fParent) {
      // new file, reset
      m_streamerChecksum = 0;
   }
   if (m_class && m_class->GetClassVersion() != 0) {
      if (m_streamerVersion <= 0) {
         *buf >> m_streamerChecksum;
         m_streamerVersion = R__FindStreamerInfoVersion(m_class, m_streamerChecksum);
      } else if (m_streamerVersion == 1) {
         // hand made streamer list caching, change that when TFile::GetStreamerInfoCache() is out      
         if (m_lastFile == fParent) {
            // the same file, nothing changed?
         } else if (fParent && fParent->GetVersion() < 40000) {
            // We could have a file created using a Foreign class before
            // the introduction of the CheckSum.  We need to check
            if ((!m_class->IsLoaded() || m_class->IsForeign()) &&
                m_class->GetStreamerInfos()->GetLast() > 1) {
               const TList* list  = fParent->GetStreamerInfoList();
               const TStreamerInfo* local = (TStreamerInfo*)list->FindObject(m_className.c_str());
               if (local) {
                  m_streamerChecksum = local->GetCheckSum();
                  m_streamerVersion = R__FindStreamerInfoVersion(m_class, m_streamerChecksum);
               } else {
                  m_streamerVersion = 0;
               }
            }
         }
      }
   }
   m_lastFile = fParent;
}

operator()()

void AthenaRootStreamer::operator() ( TBuffer &  b, void *  obj  )

virtual

this operator is colled by ROOT to ready and write objects

Definition at line 54 of file AthenaRootStreamer.cxx.

                                                         {
   if (b.IsReading()) {
      UInt_t R__s, R__c;
      FindVersion(&b, &R__s, &R__c);
      // find converter for the object shape checksum
      // (checksum is read from the file in FindVersion)
      auto it = m_converterMap.find(m_streamerChecksum);
      if (it != m_converterMap.end()) {
         it->second->ReadBuffer(b, obj, m_streamerVersion, R__s, R__c);
      } else {
     if(m_service) {
        if( m_seenChecksums.find( m_streamerChecksum ) == m_seenChecksums.end() ) {
           // report unknown checksums only once
           MsgStream log(m_service->msgSvc(), m_service->name()); 
           log << MSG::INFO << "Found unknown streamer checksum " << m_streamerChecksum
           << " for class "
           << m_className << " - using default ROOT streamer" << endmsg;
           m_seenChecksums.insert( m_streamerChecksum );
        }
     }
         m_class->ReadBuffer(b, obj, m_streamerVersion, R__s, R__c);
      }
   } else {
      m_class->WriteBuffer(b, obj);
   }
}

R__FindStreamerInfoVersion()

Version_t AthenaRootStreamer::R__FindStreamerInfoVersion ( const TClass *  cl, UInt_t  checksum  )

staticprotected

Definition at line 163 of file AthenaRootStreamer.cxx.

                                                                                          {
   //find the version number in the StreamerInfos corresponding to checksum
   Version_t version = 0;
   Int_t ninfos = cl->GetStreamerInfos()->GetEntriesFast();
   for (Int_t i = 1; i < ninfos; i++) {
      // TClass::fStreamerInfos has a lower bound not equal to 0,
      // so we should use At and not use UncheckedAt
      TStreamerInfo* info = (TStreamerInfo*)cl->GetStreamerInfos()->At(i);
      if (!info) {
         continue;
      }
      if (info->GetCheckSum() == checksum) {
         version = i;
         break;
      }
   }
   return(version);
}

Member Data Documentation

m_class

TClass* AthenaRootStreamer::m_class

private

Definition at line 61 of file AthenaRootStreamer.h.

m_className

std::string AthenaRootStreamer::m_className

private

Definition at line 60 of file AthenaRootStreamer.h.

m_converterMap

ConverterMap AthenaRootStreamer::m_converterMap

private

Definition at line 67 of file AthenaRootStreamer.h.

m_lastFile

TFile* AthenaRootStreamer::m_lastFile

private

Definition at line 64 of file AthenaRootStreamer.h.

m_seenChecksums

ChecksumSet AthenaRootStreamer::m_seenChecksums

private

Definition at line 70 of file AthenaRootStreamer.h.

m_service

Service* AthenaRootStreamer::m_service

private

Definition at line 72 of file AthenaRootStreamer.h.

m_streamerChecksum

UInt_t AthenaRootStreamer::m_streamerChecksum

private

Definition at line 62 of file AthenaRootStreamer.h.

m_streamerVersion

Version_t AthenaRootStreamer::m_streamerVersion

private

Definition at line 63 of file AthenaRootStreamer.h.

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

• AthenaRootStreamer.h
• AthenaRootStreamer.cxx