Function SetupPythonPaths

Utilities/PythonInterpreter/vtkPythonInterpreter.cxx:329–409

------------------------------------------------------------------------------ * Add paths to VTK's Python modules. */

 * Add paths to VTK's Python modules.
 */
void SetupPythonPaths(bool isolated, std::string vtklib, const char* landmark)
{
  // Check if we're using an isolated Python.
  if (isolated)
  {
    VTKPY_DEBUG_MESSAGE("Isolated Python detected; skipping setting up of `vtk` package.");
    return;
  }

  using systools = vtksys::SystemTools;
  if (vtklib.empty())
  {
    VTKPY_DEBUG_MESSAGE(
      "`GetVTKVersion` library couldn't be found. Will use `sys.executable` next.");
  }

  if (vtklib.empty())
  {
#if PY_VERSION_HEX >= 0x03080000
    vtkPythonScopeGilEnsurer gilEnsurer;
    PyObject* executable_path = PySys_GetObject("executable");
    if (executable_path != Py_None)
    {
      vtklib = PyUnicode_AsUTF8AndSize(executable_path, nullptr);
    }
#else
    vtklib = vtk_Py_WideToUTF8(Py_GetProgramName());
#endif
  }

  vtklib = systools::CollapseFullPath(vtklib);
  const std::string vtkdir = systools::GetFilenamePath(vtklib);

#if defined(_WIN32) && !defined(__CYGWIN__) && defined(VTK_BUILD_SHARED_LIBS)
  // On Windows, based on how the executable is run, we end up failing to load
  // pyd files due to inability to load dependent dlls. This seems to overcome
  // the issue.
  if (!vtkdir.empty())
  {
#if PY_VERSION_HEX >= 0x03080000
    vtkPythonScopeGilEnsurer gilEnsurer;
    CloseDLLDirectoryCookie();
    PyObject* os = PyImport_ImportModule("os");
    if (os)
    {
      PyObject* add_dll_directory = PyObject_GetAttrString(os, "add_dll_directory");
      if (add_dll_directory && PyCallable_Check(add_dll_directory))
      {
        PyObject* newpath = PyUnicode_FromString(vtkdir.c_str());
        DLLDirectoryCookie = PyObject_CallFunctionObjArgs(add_dll_directory, newpath, nullptr);
        Py_XDECREF(newpath);
      }

      Py_XDECREF(add_dll_directory);
    }

    Py_XDECREF(os);
#else