Init.cxx

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// Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
 
// System include(s):
#include <atomic>
#include <iostream>
#include <iomanip>
#include <cstring>
#include <string>
#include <cstdlib>
#include <sstream>
 
// ROOT include(s):
#include <TApplication.h>
#include <TClass.h>
#include <TError.h>
#include <TSystem.h>
 
// Local include(s):
#include "CxxUtils/checker_macros.h"
#include "xAODRootAccess/Init.h"
 
namespace xAOD {

   void ErrorHandler ATLAS_NOT_THREAD_SAFE ( Int_t level, Bool_t abort, const char* location,
                                             const char* message );

   static std::atomic<size_t> sMessageSourceWidth = 25;
 
   StatusCode Init( const char* appname ) {
 
      return Init( appname, 0, 0 );
   }
 
   StatusCode Init( const char* appname, int* argc, char** argv ) {
 
      static std::atomic_flag sInitialised ATLAS_THREAD_SAFE = ATOMIC_FLAG_INIT;
 
      // Check if we need to do anything:
      if( ! sInitialised.test_and_set() ) {
 
         // Set up our own error handler function:
         ::SetErrorHandler( ErrorHandler );
 
         // Create an application. This is needed to ensure the auto-loading
         // of the xAOD dictionaries.
         TApplication* app ATLAS_THREAD_SAFE = gApplication;  // suppress checker warning (protected above)
         if( ! app ) {
            if( argc && argv ) {
               [[maybe_unused]]
               static ::TApplication sApplication( appname, argc, argv );
            } else {
               ::TApplication::CreateApplication();
            }
         }
 
         // Load the libraries in a carefully selected order.
         // This is a temporary work-around (26 Oct 20) until the current
         // xAOD dictionary issues are worked out.
         for (const char *name : {
               "xAOD::TruthParticle_v1",
               "xAOD::MuonRoI_v1",
               "xAOD::CaloCluster_v1",
               "xAOD::TrackParticle_v1",
               "xAOD::Electron_v1",
               "xAOD::Muon_v1",
               "xAOD::Jet_v1",
               "xAOD::TauJet_v1",
               "xAOD::PFO_v1",
               "xAOD::TrigElectron_v1",
               "xAOD::L2CombinedMuon_v1",
               "xAOD::Particle_v1"}) {
            // silently ignore missing classes, because this gets used in
            // all projects, and not all projects contain all xAOD classes
            static constexpr Bool_t LOAD = kTRUE;
            static constexpr Bool_t SILENT = kTRUE;
            TClass::GetClass( name, LOAD, SILENT );
         }
 
         // Let the user know what happened:
         ::Info( appname, "Environment initialised for data access" );
      }
 
      // Return gracefully:
      return StatusCode::SUCCESS;
   }
 
   void SetMessageSourceWidth( size_t value ) {
 
      sMessageSourceWidth = value;
      return;
   }

   void ErrorHandler ATLAS_NOT_THREAD_SAFE ( Int_t level, Bool_t abort, const char* location,
                                             const char* message ) {
 
      // Check if we need to print anything for this level:
      if( level < gErrorIgnoreLevel ) {
         return;
      }
 
      // Source of the missing dictionary warnings:
      static const char* const DICT_WARNING_SOURCE = "TClass::Init";
 
      // Filter out warnings about missing dictionaries. As these are relatively
      // common. In case a problem occurs because of a missing dictionary, some
      // other piece of code will complain anyway.
      if( ( level == kWarning ) &&
          ( ! strcmp( location, DICT_WARNING_SOURCE ) ) ) {
         return;
      }
 
      // Construct a string version of the message's level:
      const char* msgLevel = 0;
      if( level >= kFatal ) {
         msgLevel = "FATAL  ";
      } else if( level >= kError ) {
         msgLevel = "ERROR  ";
      } else if( level >= kWarning ) {
         msgLevel = "WARNING";
      } else {
         msgLevel = "INFO   ";
      }
 
      // Make sure that the message's source/location is not longer than a
      // pre-set maximum value:
      std::string source( location );
      if( source.size() > sMessageSourceWidth ) {
         source.resize( sMessageSourceWidth - 3 );
         source += "...";
      }
 
      // Print the message to stdout/std::cout:
      std::ostringstream output;
      output << std::setiosflags( std::ios::left )
             << std::setw( sMessageSourceWidth ) << source << " " << msgLevel
             << " " << message;
      std::cout << output.str() << std::endl;
 
      // If we don't need to abort, return now:
      if( ! abort ) {
         return;
      }
 
      // Abort with a stack trace if possible:
      std::cout << std::endl << "Aborting..." << std::endl;
      if( gSystem ) {
         gSystem->StackTrace();
         gSystem->Abort();
      } else {
         std::abort();
      }
 
      return;
   }
 
} // namespace xAOD