Threading.h

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// ----------------------------------------------------------------------------
// -                        CloudViewer: www.cloudViewer.org                  -
// ----------------------------------------------------------------------------
// Copyright (c) 2018-2024 www.cloudViewer.org
// SPDX-License-Identifier: MIT
// ----------------------------------------------------------------------------
 
#pragma once
 
#include <QException>
 
#include <pybind11/pybind11.h>
 
namespace py = pybind11;
 
class PyThreadStateGuard
{
  public:
    explicit PyThreadStateGuard(PyInterpreterState *interpState)
    {
        pCurrentState = PyThreadState_New(interpState);
        PyEval_AcquireThread(pCurrentState);
    }
 
    virtual ~PyThreadStateGuard()
    {
        PyThreadState_Clear(pCurrentState);
        PyEval_ReleaseThread(pCurrentState);
 
        PyThreadState_Delete(pCurrentState);
    }
 
  private:
    PyThreadState *pCurrentState{nullptr};
};
 
struct PyThreadStateReleaser
{
    explicit PyThreadStateReleaser() : state(PyEval_SaveThread()) {}
 
    virtual ~PyThreadStateReleaser()
    {
        PyEval_RestoreThread(state);
    }
 
    PyThreadState *state{nullptr};
};
 
class ThreadException : public QException
{
  public:
    explicit ThreadException(const std::exception &err) : e(err) {}
 
    void raise() const override
    {
        throw *this;
    }
 
    QException *clone() const override
    {
        return new ThreadException(*this);
    }
 
    const char *what() const noexcept override
    {
        return e.what();
    }
 
    std::exception error() const
    {
        return e;
    }
 
  private:
    std::exception e;
};
 
inline py::object
call_fn(PyThreadState *main_state, py::object callable, py::args args, py::kwargs kwargs)
{
    PyThreadStateGuard threadStateGuard{main_state->interp};
    try
    {
        return callable(*args, **kwargs);
    }
    catch (const std::exception &e)
    {
        throw ThreadException(e);
    }
}