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/*=========================================================================
*
* Copyright NumFOCUS
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
#include "itkPyCommand.h"
namespace
{
// Wrapper to automatics obtain and release GIL
// RAII idiom
class PyGILStateEnsure
{
public:
PyGILStateEnsure() { m_GIL = PyGILState_Ensure(); }
~PyGILStateEnsure() { PyGILState_Release(m_GIL); }
private:
PyGILState_STATE m_GIL;
};
} // end anonymous namespace
namespace itk
{
PyCommand::PyCommand()
{
this->m_Object = nullptr;
}
PyCommand::~PyCommand()
{
if (this->m_Object)
{
PyGILStateEnsure gil;
Py_DECREF(this->m_Object);
}
this->m_Object = nullptr;
}
void
PyCommand::SetCommandCallable(PyObject * o)
{
if (o != this->m_Object)
{
PyGILStateEnsure gil;
if (this->m_Object)
{
// get rid of our reference
Py_DECREF(this->m_Object);
}
// store the new object
this->m_Object = o;
if (this->m_Object)
{
// take out reference (so that the calling code doesn't
// have to keep a binding to the callable around)
Py_INCREF(this->m_Object);
}
}
}
PyObject *
PyCommand::GetCommandCallable()
{
return this->m_Object;
}
void
PyCommand::Execute(Object *, const EventObject &)
{
this->PyExecute();
}
void
PyCommand::Execute(const Object *, const EventObject &)
{
this->PyExecute();
}
void
PyCommand::PyExecute()
{
// make sure that the CommandCallable is in fact callable
if (!PyCallable_Check(this->m_Object))
{
// we throw a standard ITK exception: this makes it possible for
// our standard Swig exception handling logic to take this
// through to the invoking Python process
itkExceptionMacro(<< "CommandCallable is not a callable Python object, "
<< "or it has not been set.");
}
else
{
PyGILStateEnsure gil;
PyObject * result = PyEval_CallObject(this->m_Object, (PyObject *)nullptr);
if (result)
{
Py_DECREF(result);
}
else
{
// there was a Python error. Clear the error by printing to stdout
PyErr_Print();
// make sure the invoking Python code knows there was a problem
// by raising an exception
itkExceptionMacro(<< "There was an error executing the "
<< "CommandCallable.");
}
}
}
} // end namespace itk
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