tests/test_class_sh_basic.cpp

#include "pybind11_tests.h"

#include <memory>
#include <string>
#include <vector>

namespace pybind11_tests {
namespace class_sh_basic {

struct atyp { // Short for "any type".
    std::string mtxt;
    atyp() : mtxt("DefaultConstructor") {}
    explicit atyp(const std::string &mtxt_) : mtxt(mtxt_) {}
    atyp(const atyp &other) { mtxt = other.mtxt + "_CpCtor"; }
    atyp(atyp &&other) noexcept { mtxt = other.mtxt + "_MvCtor"; }
};

struct uconsumer { // unique_ptr consumer
    std::unique_ptr<atyp> held;
    bool valid() const { return static_cast<bool>(held); }

    void pass_valu(std::unique_ptr<atyp> obj) { held = std::move(obj); }
    void pass_rref(std::unique_ptr<atyp> &&obj) { held = std::move(obj); }
    std::unique_ptr<atyp> rtrn_valu() { return std::move(held); }
    std::unique_ptr<atyp> &rtrn_lref() { return held; }
    const std::unique_ptr<atyp> &rtrn_cref() const { return held; }
};

/// Custom deleter that is default constructible.
struct custom_deleter {
    std::string trace_txt;

    custom_deleter() = default;
    explicit custom_deleter(const std::string &trace_txt_) : trace_txt(trace_txt_) {}

    custom_deleter(const custom_deleter &other) { trace_txt = other.trace_txt + "_CpCtor"; }

    custom_deleter &operator=(const custom_deleter &rhs) {
        trace_txt = rhs.trace_txt + "_CpLhs";
        return *this;
    }

    custom_deleter(custom_deleter &&other) noexcept {
        trace_txt = other.trace_txt + "_MvCtorTo";
        other.trace_txt += "_MvCtorFrom";
    }

    custom_deleter &operator=(custom_deleter &&rhs) noexcept {
        trace_txt = rhs.trace_txt + "_MvLhs";
        rhs.trace_txt += "_MvRhs";
        return *this;
    }

    void operator()(atyp *p) const { std::default_delete<atyp>()(p); }
    void operator()(const atyp *p) const { std::default_delete<const atyp>()(p); }
};
static_assert(std::is_default_constructible<custom_deleter>::value, "");

/// Custom deleter that is not default constructible.
struct custom_deleter_nd : custom_deleter {
    custom_deleter_nd() = delete;
    explicit custom_deleter_nd(const std::string &trace_txt_) : custom_deleter(trace_txt_) {}
};
static_assert(!std::is_default_constructible<custom_deleter_nd>::value, "");

// clang-format off

atyp        rtrn_valu() { atyp obj{"rtrn_valu"}; return obj; }
atyp&&      rtrn_rref() { static atyp obj; obj.mtxt = "rtrn_rref"; return std::move(obj); }
atyp const& rtrn_cref() { static atyp obj; obj.mtxt = "rtrn_cref"; return obj; }
atyp&       rtrn_mref() { static atyp obj; obj.mtxt = "rtrn_mref"; return obj; }
atyp const* rtrn_cptr() { return new atyp{"rtrn_cptr"}; }
atyp*       rtrn_mptr() { return new atyp{"rtrn_mptr"}; }

std::string pass_valu(atyp obj)        { return "pass_valu:" + obj.mtxt; } // NOLINT
std::string pass_cref(atyp const& obj) { return "pass_cref:" + obj.mtxt; }
std::string pass_mref(atyp& obj)       { return "pass_mref:" + obj.mtxt; }
std::string pass_cptr(atyp const* obj) { return "pass_cptr:" + obj->mtxt; }
std::string pass_mptr(atyp* obj)       { return "pass_mptr:" + obj->mtxt; }

std::shared_ptr<atyp>       rtrn_shmp() { return std::make_shared<atyp>("rtrn_shmp"); }
std::shared_ptr<atyp const> rtrn_shcp() { return std::shared_ptr<atyp const>(new atyp{"rtrn_shcp"}); }

std::string pass_shmp(std::shared_ptr<atyp>       obj) { return "pass_shmp:" + obj->mtxt; } // NOLINT
std::string pass_shcp(std::shared_ptr<atyp const> obj) { return "pass_shcp:" + obj->mtxt; } // NOLINT

std::unique_ptr<atyp>       rtrn_uqmp() { return std::unique_ptr<atyp      >(new atyp{"rtrn_uqmp"}); }
std::unique_ptr<atyp const> rtrn_uqcp() { return std::unique_ptr<atyp const>(new atyp{"rtrn_uqcp"}); }

std::string pass_uqmp(std::unique_ptr<atyp      > obj) { return "pass_uqmp:" + obj->mtxt; }
std::string pass_uqcp(std::unique_ptr<atyp const> obj) { return "pass_uqcp:" + obj->mtxt; }

struct sddm : std::default_delete<atyp      > {};
struct sddc : std::default_delete<atyp const> {};

std::unique_ptr<atyp,       sddm> rtrn_udmp() { return std::unique_ptr<atyp,       sddm>(new atyp{"rtrn_udmp"}); }
std::unique_ptr<atyp const, sddc> rtrn_udcp() { return std::unique_ptr<atyp const, sddc>(new atyp{"rtrn_udcp"}); }

std::string pass_udmp(std::unique_ptr<atyp,       sddm> obj) { return "pass_udmp:" + obj->mtxt; }
std::string pass_udcp(std::unique_ptr<atyp const, sddc> obj) { return "pass_udcp:" + obj->mtxt; }

std::unique_ptr<atyp,       custom_deleter> rtrn_udmp_del() { return std::unique_ptr<atyp,       custom_deleter>(new atyp{"rtrn_udmp_del"}, custom_deleter{"udmp_deleter"}); }
std::unique_ptr<atyp const, custom_deleter> rtrn_udcp_del() { return std::unique_ptr<atyp const, custom_deleter>(new atyp{"rtrn_udcp_del"}, custom_deleter{"udcp_deleter"}); }

std::string pass_udmp_del(std::unique_ptr<atyp,       custom_deleter> obj) { return "pass_udmp_del:" + obj->mtxt + "," + obj.get_deleter().trace_txt; }
std::string pass_udcp_del(std::unique_ptr<atyp const, custom_deleter> obj) { return "pass_udcp_del:" + obj->mtxt + "," + obj.get_deleter().trace_txt; }

std::unique_ptr<atyp,       custom_deleter_nd> rtrn_udmp_del_nd() { return std::unique_ptr<atyp,       custom_deleter_nd>(new atyp{"rtrn_udmp_del_nd"}, custom_deleter_nd{"udmp_deleter_nd"}); }
std::unique_ptr<atyp const, custom_deleter_nd> rtrn_udcp_del_nd() { return std::unique_ptr<atyp const, custom_deleter_nd>(new atyp{"rtrn_udcp_del_nd"}, custom_deleter_nd{"udcp_deleter_nd"}); }

std::string pass_udmp_del_nd(std::unique_ptr<atyp,       custom_deleter_nd> obj) { return "pass_udmp_del_nd:" + obj->mtxt + "," + obj.get_deleter().trace_txt; }
std::string pass_udcp_del_nd(std::unique_ptr<atyp const, custom_deleter_nd> obj) { return "pass_udcp_del_nd:" + obj->mtxt + "," + obj.get_deleter().trace_txt; }

// clang-format on

// Helpers for testing.
std::string get_mtxt(atyp const &obj) { return obj.mtxt; }
std::ptrdiff_t get_ptr(atyp const &obj) { return reinterpret_cast<std::ptrdiff_t>(&obj); }

std::unique_ptr<atyp> unique_ptr_roundtrip(std::unique_ptr<atyp> obj) { return obj; }

std::string pass_unique_ptr_cref(const std::unique_ptr<atyp> &obj) { return obj->mtxt; }

const std::unique_ptr<atyp> &rtrn_unique_ptr_cref(const std::string &mtxt) {
    static std::unique_ptr<atyp> obj{new atyp{"static_ctor_arg"}};
    if (!mtxt.empty()) {
        obj->mtxt = mtxt;
    }
    return obj;
}

const std::unique_ptr<atyp> &unique_ptr_cref_roundtrip(const std::unique_ptr<atyp> &obj) {
    // This is passed in, so it can't be given a temporary
    return obj; // NOLINT(bugprone-return-const-ref-from-parameter)
}

struct SharedPtrStash {
    std::vector<std::shared_ptr<const atyp>> stash;
    void Add(const std::shared_ptr<const atyp> &obj) { stash.push_back(obj); }
};

class LocalUnusualOpRef : UnusualOpRef {}; // To avoid clashing with `py::class_<UnusualOpRef>`.
py::object CastUnusualOpRefConstRef(const LocalUnusualOpRef &cref) { return py::cast(cref); }
py::object CastUnusualOpRefMovable(LocalUnusualOpRef &&mvbl) { return py::cast(std::move(mvbl)); }

TEST_SUBMODULE(class_sh_basic, m) {
    namespace py = pybind11;

    py::classh<atyp>(m, "atyp").def(py::init<>()).def(py::init([](const std::string &mtxt) {
        atyp obj;
        obj.mtxt = mtxt;
        return obj;
    }));

    m.def("rtrn_valu", rtrn_valu);
    m.def("rtrn_rref", rtrn_rref);
    m.def("rtrn_cref", rtrn_cref);
    m.def("rtrn_mref", rtrn_mref);
    m.def("rtrn_cptr", rtrn_cptr);
    m.def("rtrn_mptr", rtrn_mptr);

    m.def("pass_valu", pass_valu);
    m.def("pass_cref", pass_cref);
    m.def("pass_mref", pass_mref);
    m.def("pass_cptr", pass_cptr);
    m.def("pass_mptr", pass_mptr);

    m.def("rtrn_shmp", rtrn_shmp);
    m.def("rtrn_shcp", rtrn_shcp);

    m.def("pass_shmp", pass_shmp);
    m.def("pass_shcp", pass_shcp);

    m.def("rtrn_uqmp", rtrn_uqmp);
    m.def("rtrn_uqcp", rtrn_uqcp);

    m.def("pass_uqmp", pass_uqmp);
    m.def("pass_uqcp", pass_uqcp);

    m.def("rtrn_udmp", rtrn_udmp);
    m.def("rtrn_udcp", rtrn_udcp);

    m.def("pass_udmp", pass_udmp);
    m.def("pass_udcp", pass_udcp);

    m.def("rtrn_udmp_del", rtrn_udmp_del);
    m.def("rtrn_udcp_del", rtrn_udcp_del);

    m.def("pass_udmp_del", pass_udmp_del);
    m.def("pass_udcp_del", pass_udcp_del);

    m.def("rtrn_udmp_del_nd", rtrn_udmp_del_nd);
    m.def("rtrn_udcp_del_nd", rtrn_udcp_del_nd);

    m.def("pass_udmp_del_nd", pass_udmp_del_nd);
    m.def("pass_udcp_del_nd", pass_udcp_del_nd);

    py::classh<uconsumer>(m, "uconsumer")
        .def(py::init<>())
        .def("valid", &uconsumer::valid)
        .def("pass_valu", &uconsumer::pass_valu)
        .def("pass_rref", &uconsumer::pass_rref)
        .def("rtrn_valu", &uconsumer::rtrn_valu)
        .def("rtrn_lref", &uconsumer::rtrn_lref)
        .def("rtrn_cref", &uconsumer::rtrn_cref);

    // Helpers for testing.
    // These require selected functions above to work first, as indicated:
    m.def("get_mtxt", get_mtxt); // pass_cref
    m.def("get_ptr", get_ptr);   // pass_cref

    m.def("unique_ptr_roundtrip", unique_ptr_roundtrip); // pass_uqmp, rtrn_uqmp

    m.def("pass_unique_ptr_cref", pass_unique_ptr_cref);
    m.def("rtrn_unique_ptr_cref", rtrn_unique_ptr_cref);
    m.def("unique_ptr_cref_roundtrip", unique_ptr_cref_roundtrip);

    py::classh<SharedPtrStash>(m, "SharedPtrStash")
        .def(py::init<>())
        .def("Add", &SharedPtrStash::Add, py::arg("obj"));

    m.def("py_type_handle_of_atyp", []() {
        return py::type::handle_of<atyp>(); // Exercises static_cast in this function.
    });

    // Checks for type names used as arguments
    m.def("args_shared_ptr", [](std::shared_ptr<atyp> p) { return p; });
    m.def("args_shared_ptr_const", [](std::shared_ptr<atyp const> p) { return p; });
    m.def("args_unique_ptr", [](std::unique_ptr<atyp> p) { return p; });
    m.def("args_unique_ptr_const", [](std::unique_ptr<atyp const> p) { return p; });

    // Make sure unique_ptr type caster accept automatic_reference return value policy.
    m.def(
        "rtrn_uq_automatic_reference",
        []() { return std::unique_ptr<atyp>(new atyp("rtrn_uq_automatic_reference")); },
        pybind11::return_value_policy::automatic_reference);

    m.def("pass_shared_ptr_ptr", [](std::shared_ptr<atyp> *) {});

    py::classh<LocalUnusualOpRef>(m, "LocalUnusualOpRef");
    m.def("CallCastUnusualOpRefConstRef",
          []() { return CastUnusualOpRefConstRef(LocalUnusualOpRef()); });
    m.def("CallCastUnusualOpRefMovable",
          []() { return CastUnusualOpRefMovable(LocalUnusualOpRef()); });
}

} // namespace class_sh_basic
} // namespace pybind11_tests