test_thread.cpp

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/*
    tests/test_thread.cpp -- call pybind11 bound methods in threads
 
    Copyright (c) 2021 Laramie Leavitt (Google LLC) <lar@google.com>
 
    All rights reserved. Use of this source code is governed by a
    BSD-style license that can be found in the LICENSE file.
*/
 
#include <pybind11/cast.h>
#include <pybind11/pybind11.h>
 
#include "pybind11_tests.h"
 
#include <chrono>
#include <thread>
 
namespace py = pybind11;
 
namespace {
 
struct IntStruct {
    explicit IntStruct(int v) : value(v) {};
    ~IntStruct() { value = -value; }
    IntStruct(const IntStruct &) = default;
    IntStruct &operator=(const IntStruct &) = default;
 
    int value;
};
 
} // namespace
 
TEST_SUBMODULE(thread, m) {
 
    py::class_<IntStruct>(m, "IntStruct").def(py::init([](const int i) { return IntStruct(i); }));
 
    // implicitly_convertible uses loader_life_support when an implicit
    // conversion is required in order to lifetime extend the reference.
    //
    // This test should be run with ASAN for better effectiveness.
    py::implicitly_convertible<int, IntStruct>();
 
    m.def("test", [](int expected, const IntStruct &in) {
        {
            py::gil_scoped_release release;
            std::this_thread::sleep_for(std::chrono::milliseconds(5));
        }
 
        if (in.value != expected) {
            throw std::runtime_error("Value changed!!");
        }
    });
 
    m.def(
        "test_no_gil",
        [](int expected, const IntStruct &in) {
            std::this_thread::sleep_for(std::chrono::milliseconds(5));
            if (in.value != expected) {
                throw std::runtime_error("Value changed!!");
            }
        },
        py::call_guard<py::gil_scoped_release>());
 
    // NOTE: std::string_view also uses loader_life_support to ensure that
    // the string contents remain alive, but that's a C++ 17 feature.
}