TPyDispatcher.cxx

Go to the documentation of this file.

// Author: Enric Tejedor CERN  07/2020
// Original PyROOT code by Wim Lavrijsen, LBL
 
/*************************************************************************
 * Copyright (C) 1995-2020, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#include "TPyDispatcher.h"
 
// Bindings
#include "CPyCppyy/API.h"
 
// ROOT
#include "TClass.h"
#include "TObject.h"
 
// Standard
#include <stdarg.h>
 
//______________________________________________________________________________
//                         Python callback dispatcher
//                         ==========================
//
// The TPyDispatcher class acts as a functor that can be used for TFn's and GUIs
// to install callbacks from Cling.
 
//- constructors/destructor --------------------------------------------------
TPyDispatcher::TPyDispatcher(PyObject *callable) : fCallable(0)
{
   // Construct a TPyDispatcher from a callable python object. Applies python
   // object reference counting.
   Py_XINCREF(callable);
   fCallable = callable;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Copy constructor. Applies python object reference counting.
 
TPyDispatcher::TPyDispatcher(const TPyDispatcher &other) : TObject(other)
{
   Py_XINCREF(other.fCallable);
   fCallable = other.fCallable;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Assignment operator. Applies python object reference counting.
 
TPyDispatcher &TPyDispatcher::operator=(const TPyDispatcher &other)
{
   if (this != &other) {
      this->TObject::operator=(other);
 
      Py_DecRef(fCallable);
      Py_XINCREF(other.fCallable);
      fCallable = other.fCallable;
   }
 
   return *this;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Destructor. Reference counting for the held python object is in effect.
 
TPyDispatcher::~TPyDispatcher()
{
   Py_DecRef(fCallable);
}
 
//- public members -----------------------------------------------------------
PyObject *TPyDispatcher::DispatchVA(const char *format, ...)
{
   // Dispatch the arguments to the held callable python object, using format to
   // interpret the types of the arguments. Note that format is in python style,
   // not in C printf style. See: https://docs.python.org/2/c-api/arg.html .
   PyObject *args = 0;
 
   if (format) {
      va_list va;
      va_start(va, format);
 
      args = Py_VaBuildValue((char *)format, va);
 
      va_end(va);
 
      if (!args) {
         PyErr_Print();
         return 0;
      }
 
      if (!PyTuple_Check(args)) { // if only one arg ...
         PyObject *t = PyTuple_New(1);
         PyTuple_SetItem(t, 0, args);
         args = t;
      }
   }
 
   PyObject *result = PyObject_CallObject(fCallable, args);
   Py_DecRef(args);
 
   if (!result) {
      PyErr_Print();
      return 0;
   }
 
   return result;
}
 
////////////////////////////////////////////////////////////////////////////////
 
PyObject *TPyDispatcher::DispatchVA1(const char *clname, void *obj, const char *format, ...)
{
   PyObject *pyobj = CPyCppyy::Instance_FromVoidPtr(obj, clname);
   if (!pyobj) {
      PyErr_Print();
      return 0;
   }
 
   PyObject *args = 0;
 
   if (format) {
      va_list va;
      va_start(va, format);
 
      args = Py_VaBuildValue((char *)format, va);
 
      va_end(va);
 
      if (!args) {
         PyErr_Print();
         return 0;
      }
 
      if (!PyTuple_Check(args)) { // if only one arg ...
         PyObject *t = PyTuple_New(2);
         PyTuple_SetItem(t, 0, pyobj);
         PyTuple_SetItem(t, 1, args);
         args = t;
      } else {
         PyObject *t = PyTuple_New(PyTuple_Size(args) + 1);
         PyTuple_SetItem(t, 0, pyobj);
         for (int i = 0; i < PyTuple_Size(args); i++) {
            PyObject *item = PyTuple_GetItem(args, i);
            Py_IncRef(item);
            PyTuple_SetItem(t, i + 1, item);
         }
         Py_DecRef(args);
         args = t;
      }
   } else {
      args = PyTuple_New(1);
      PyTuple_SetItem(args, 0, pyobj);
   }
 
   PyObject *result = PyObject_CallObject(fCallable, args);
   Py_DecRef(args);
 
   if (!result) {
      PyErr_Print();
      return 0;
   }
 
   return result;
}
 
////////////////////////////////////////////////////////////////////////////////
 
PyObject *TPyDispatcher::Dispatch(TPad *selpad, TObject *selected, Int_t event)
{
   PyObject *args = PyTuple_New(3);
   PyTuple_SetItem(args, 0, CPyCppyy::Instance_FromVoidPtr(selpad, "TPad"));
   PyTuple_SetItem(args, 1, CPyCppyy::Instance_FromVoidPtr(selected, "TObject"));
   PyTuple_SetItem(args, 2, PyLong_FromLong(event));
 
   PyObject *result = PyObject_CallObject(fCallable, args);
   Py_DecRef(args);
 
   if (!result) {
      PyErr_Print();
      return 0;
   }
 
   return result;
}
 
////////////////////////////////////////////////////////////////////////////////
 
PyObject *TPyDispatcher::Dispatch(Int_t event, Int_t x, Int_t y, TObject *selected)
{
   PyObject *args = PyTuple_New(4);
   PyTuple_SetItem(args, 0, PyLong_FromLong(event));
   PyTuple_SetItem(args, 1, PyLong_FromLong(x));
   PyTuple_SetItem(args, 2, PyLong_FromLong(y));
   PyTuple_SetItem(args, 3, CPyCppyy::Instance_FromVoidPtr(selected, "TObject"));
 
   PyObject *result = PyObject_CallObject(fCallable, args);
   Py_DecRef(args);
 
   if (!result) {
      PyErr_Print();
      return 0;
   }
 
   return result;
}
 
////////////////////////////////////////////////////////////////////////////////
 
PyObject *TPyDispatcher::Dispatch(TVirtualPad *pad, TObject *obj, Int_t event)
{
   PyObject *args = PyTuple_New(3);
   PyTuple_SetItem(args, 0, CPyCppyy::Instance_FromVoidPtr(pad, "TVirtualPad"));
   PyTuple_SetItem(args, 1, CPyCppyy::Instance_FromVoidPtr(obj, "TObject"));
   PyTuple_SetItem(args, 2, PyLong_FromLong(event));
 
   PyObject *result = PyObject_CallObject(fCallable, args);
   Py_DecRef(args);
 
   if (!result) {
      PyErr_Print();
      return 0;
   }
 
   return result;
}
 
////////////////////////////////////////////////////////////////////////////////
 
PyObject *TPyDispatcher::Dispatch(TGListTreeItem *item, TDNDData *data)
{
   PyObject *args = PyTuple_New(2);
   PyTuple_SetItem(args, 0, CPyCppyy::Instance_FromVoidPtr(item, "TGListTreeItem"));
   PyTuple_SetItem(args, 1, CPyCppyy::Instance_FromVoidPtr(data, "TDNDData"));
 
   PyObject *result = PyObject_CallObject(fCallable, args);
   Py_DecRef(args);
 
   if (!result) {
      PyErr_Print();
      return 0;
   }
 
   return result;
}
 
////////////////////////////////////////////////////////////////////////////////
 
PyObject *TPyDispatcher::Dispatch(const char *name, const TList *attr)
{
   PyObject *args = PyTuple_New(2);
   PyTuple_SetItem(args, 0, PyBytes_FromString(name));
   PyTuple_SetItem(args, 1, CPyCppyy::Instance_FromVoidPtr((void *)attr, "TList"));
 
   PyObject *result = PyObject_CallObject(fCallable, args);
   Py_DecRef(args);
 
   if (!result) {
      PyErr_Print();
      return 0;
   }
 
   return result;
}