TClassPyz.cxx

Go to the documentation of this file.

// Author: Enric Tejedor CERN  02/2019
// Original PyROOT code by Wim Lavrijsen, LBL
 
/*************************************************************************
 * Copyright (C) 1995-2019, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
// Bindings
#include "CPyCppyy/API.h"
 
#include "../../cppyy/CPyCppyy/src/CPyCppyy.h"
#include "../../cppyy/CPyCppyy/src/CPPInstance.h"
#include "../../cppyy/CPyCppyy/src/Utility.h"
 
#include "PyROOTPythonize.h"
 
// ROOT
#include "TClass.h"
 
using namespace CPyCppyy;
 
// Cast the void* returned by TClass::DynamicCast to the right type
PyObject *TClassDynamicCastPyz(PyObject *self, PyObject *args)
{
   // Parse arguments
   PyObject *pyclass = nullptr;
   PyObject *pyobject = nullptr;
   int up = 1;
   if (!PyArg_ParseTuple(args, "O!O|i:DynamicCast",
                         &CPPInstance_Type, &pyclass,
                         &pyobject,
                         &up))
      return nullptr;
 
   // Perform actual cast - calls default implementation of DynamicCast
   TClass *cl1 = (TClass *)CPyCppyy::Instance_AsVoidPtr(self);
   TClass *cl2 = (TClass *)CPyCppyy::Instance_AsVoidPtr(pyclass);
 
   void *address = cl1->DynamicCast(cl2, CPyCppyy::Instance_AsVoidPtr(pyobject), up);
 
   if (CPyCppyy::Instance_Check(pyobject)) {
      address = CPyCppyy::Instance_AsVoidPtr(pyobject);
   } else if (PyInt_Check(pyobject) || PyLong_Check(pyobject)) {
      address = (void *)PyLong_AsLongLong(pyobject);
   } else {
      Utility::GetBuffer(pyobject, '*', 1, address, false);
   }
 
   // Now use binding to return a usable class. Upcast: result is a base.
   // Downcast: result is a derived.
   Cppyy::TCppType_t cpptype = ((CPyCppyy::CPPInstance*)(up ? pyclass : self))->ObjectIsA();
   TClass *tcl = TClass::GetClass(Cppyy::GetScopedFinalName(cpptype).c_str());
   TClass *klass = (TClass *)tcl->DynamicCast(TClass::Class(), up ? CPyCppyy::Instance_AsVoidPtr(pyclass) : cl1);
 
   return CPyCppyy::Instance_FromVoidPtr(address, klass->GetName());
}
 
////////////////////////////////////////////////////////////////////////////
/// \brief Add pythonization for TClass::DynamicCast.
/// \param[in] self Always null, since this is a module function.
/// \param[in] args Pointer to a Python tuple object containing the arguments
/// received from Python.
///
/// TClass::DynamicCast returns a void* that the user still has to cast (it
/// will have the proper offset, though). Fix this by providing the requested
/// binding if the cast succeeded.
PyObject *PyROOT::AddTClassDynamicCastPyz(PyObject * /* self */, PyObject *args)
{
   PyObject *pyclass = PyTuple_GetItem(args, 0);
   Utility::AddToClass(pyclass, "DynamicCast", (PyCFunction)TClassDynamicCastPyz);
   Py_RETURN_NONE;
}