PyAthenaAlg.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
// PyAthenaAlg.cxx 
// Implementation file for class PyAthena::Alg
// Author: S.Binet<binet@cern.ch>
// Modified: Wim Lavrijsen <WLavrijsen@lbl.gov>
 
// Python includes
#include "Python.h"
 
// PyROOT includes
#include "TPython.h"
 
// AthenaPython includes
#include "AthenaPython/PyAthenaUtils.h"
#include "AthenaPython/PyAthenaAlg.h"
#include "RootUtils/PyAthenaGILStateEnsure.h"
 
// STL includes
 
// FrameWork includes
#include "GaudiKernel/System.h"
#include "GaudiKernel/MsgStream.h"
#include "GaudiKernel/ServiceHandle.h"
#include "AthenaPython/IPyComponentMgr.h"
 
namespace PyAthena {

// Public methods: 
 
// Constructors
Alg::Alg( const std::string& name, ISvcLocator* svcLocator ) :
  AlgBase_t( name, svcLocator ),
  m_self   ( nullptr )
{}
 
// Destructor
Alg::~Alg()
{ 
  ATH_MSG_DEBUG("Calling destructor");
  if ( m_self ) {
    RootUtils::PyGILStateEnsure ensure;
    Py_DECREF( m_self );
    m_self = nullptr;
  }
}
 
// Framework's Hooks
StatusCode 
Alg::initialize()
{
  ATH_MSG_INFO("Initializing " << name() << "...");
  return PyAthena::callPyMethod( m_self, "sysInitialize" );
}
 
StatusCode 
Alg::reinitialize()
{
  ATH_MSG_INFO("Re-Initializing " << name() << "...");
  return PyAthena::callPyMethod( m_self, "sysReinitialize" );
}
 
StatusCode 
Alg::start()
{ 
  return PyAthena::callPyMethod( m_self, "sysStart" );
}
 
StatusCode 
Alg::stop()
{
  return PyAthena::callPyMethod( m_self, "sysStop" );
}
 
StatusCode 
Alg::finalize()
{
  ATH_MSG_INFO("Finalizing " << name() << "...");
  return PyAthena::callPyMethod( m_self, "sysFinalize" );
}
 
StatusCode 
Alg::execute(const EventContext& ctx)
{  
  RootUtils::PyGILStateEnsure ensure;
  PyObject* pycontext = PyCapsule_New ( const_cast<EventContext*>(&ctx), nullptr, nullptr);
 
  StatusCode sc = PyAthena::callPyMethod( m_self, "sysExecute", pycontext );
  Py_DECREF (pycontext);
  return sc;
}
 
StatusCode
Alg::sysInitialize()
{
  ServiceHandle<IPyComponentMgr> pyMgr
    ( "PyAthena::PyComponentMgr/PyComponentMgr", name() );
  if ( !pyMgr.retrieve().isSuccess() ) {
    ATH_MSG_ERROR("Could not retrieve service [" << pyMgr.typeAndName()
                  << "] !!");
    return StatusCode::FAILURE;
  }
 
  // first retrieve our python object cousin...
  m_self = pyMgr->pyObject( this );
 
  if ( m_self == Py_None ) {
    ATH_MSG_ERROR("Wrapped PyObject is NONE !");
    return StatusCode::FAILURE;
  }
 
  // re-route to usual sysInit...
  return AlgBase_t::sysInitialize();
}

// Const methods: 
 
const char*
Alg::typeName() const
{ 
  static const std::string tname = System::typeinfoName(typeid(*this));
  return tname.c_str();
}

// Non-const methods: 
 
bool
Alg::setPyAttr( PyObject* o )
{
  // now we tell the PyObject which C++ object it is the cousin of.
  RootUtils::PyGILStateEnsure ensure;
  PyObject* pyobj = TPython::CPPInstance_FromVoidPtr
    ( (void*)this, this->typeName() );
  if ( !pyobj ) {
    PyErr_Clear();
    // try PyAthena::Alg
    pyobj = TPython::CPPInstance_FromVoidPtr ((void*)this, "PyAthena::Alg");
    ATH_MSG_INFO
      ("could not dyncast component [" << name() << "] to a python "
       << "object of type [" << this->typeName() << "] (probably a missing "
       << "dictionary)" << endmsg
       << "fallback to [PyAthena::Alg]...");
  }
  if ( !pyobj ) {
    PyErr_Clear();
    ATH_MSG_WARNING("Could not dyncast component ["
                    << name() << "] to a pyobject of type [" 
                    << this->typeName() << "]");
  } else {
    if ( -1 == PyObject_SetAttrString(o, "_cppHandle", pyobj) ) {
      PyErr_Clear();
      ATH_MSG_WARNING
        ("Could not attach C++ handle [" << name() << "] to its python "
         << "cousin !");
      if ( -1 == PyObject_SetAttrString(o, "_cppHandle", Py_None) ) {
        PyErr_Clear();
        ATH_MSG_WARNING
          ("could not attach a dummy C++ handle [" << name() << "] to its "
           "python cousin !");
      }
    } else {
      return true;
    }
  }
  return false;
}
 
 
} //> end namespace PyAthena