test_copy_move.cpp revision 14299:2fbea9df56d2 
1/*
2    tests/test_copy_move_policies.cpp -- 'copy' and 'move' return value policies
3                                         and related tests
4
5    Copyright (c) 2016 Ben North <ben@redfrontdoor.org>
6
7    All rights reserved. Use of this source code is governed by a
8    BSD-style license that can be found in the LICENSE file.
9*/
10
11#include "pybind11_tests.h"
12#include "constructor_stats.h"
13#include <pybind11/stl.h>
14
15template <typename derived>
16struct empty {
17    static const derived& get_one() { return instance_; }
18    static derived instance_;
19};
20
21struct lacking_copy_ctor : public empty<lacking_copy_ctor> {
22    lacking_copy_ctor() {}
23    lacking_copy_ctor(const lacking_copy_ctor& other) = delete;
24};
25
26template <> lacking_copy_ctor empty<lacking_copy_ctor>::instance_ = {};
27
28struct lacking_move_ctor : public empty<lacking_move_ctor> {
29    lacking_move_ctor() {}
30    lacking_move_ctor(const lacking_move_ctor& other) = delete;
31    lacking_move_ctor(lacking_move_ctor&& other) = delete;
32};
33
34template <> lacking_move_ctor empty<lacking_move_ctor>::instance_ = {};
35
36/* Custom type caster move/copy test classes */
37class MoveOnlyInt {
38public:
39    MoveOnlyInt() { print_default_created(this); }
40    MoveOnlyInt(int v) : value{std::move(v)} { print_created(this, value); }
41    MoveOnlyInt(MoveOnlyInt &&m) { print_move_created(this, m.value); std::swap(value, m.value); }
42    MoveOnlyInt &operator=(MoveOnlyInt &&m) { print_move_assigned(this, m.value); std::swap(value, m.value); return *this; }
43    MoveOnlyInt(const MoveOnlyInt &) = delete;
44    MoveOnlyInt &operator=(const MoveOnlyInt &) = delete;
45    ~MoveOnlyInt() { print_destroyed(this); }
46
47    int value;
48};
49class MoveOrCopyInt {
50public:
51    MoveOrCopyInt() { print_default_created(this); }
52    MoveOrCopyInt(int v) : value{std::move(v)} { print_created(this, value); }
53    MoveOrCopyInt(MoveOrCopyInt &&m) { print_move_created(this, m.value); std::swap(value, m.value); }
54    MoveOrCopyInt &operator=(MoveOrCopyInt &&m) { print_move_assigned(this, m.value); std::swap(value, m.value); return *this; }
55    MoveOrCopyInt(const MoveOrCopyInt &c) { print_copy_created(this, c.value); value = c.value; }
56    MoveOrCopyInt &operator=(const MoveOrCopyInt &c) { print_copy_assigned(this, c.value); value = c.value; return *this; }
57    ~MoveOrCopyInt() { print_destroyed(this); }
58
59    int value;
60};
61class CopyOnlyInt {
62public:
63    CopyOnlyInt() { print_default_created(this); }
64    CopyOnlyInt(int v) : value{std::move(v)} { print_created(this, value); }
65    CopyOnlyInt(const CopyOnlyInt &c) { print_copy_created(this, c.value); value = c.value; }
66    CopyOnlyInt &operator=(const CopyOnlyInt &c) { print_copy_assigned(this, c.value); value = c.value; return *this; }
67    ~CopyOnlyInt() { print_destroyed(this); }
68
69    int value;
70};
71NAMESPACE_BEGIN(pybind11)
72NAMESPACE_BEGIN(detail)
73template <> struct type_caster<MoveOnlyInt> {
74    PYBIND11_TYPE_CASTER(MoveOnlyInt, _("MoveOnlyInt"));
75    bool load(handle src, bool) { value = MoveOnlyInt(src.cast<int>()); return true; }
76    static handle cast(const MoveOnlyInt &m, return_value_policy r, handle p) { return pybind11::cast(m.value, r, p); }
77};
78
79template <> struct type_caster<MoveOrCopyInt> {
80    PYBIND11_TYPE_CASTER(MoveOrCopyInt, _("MoveOrCopyInt"));
81    bool load(handle src, bool) { value = MoveOrCopyInt(src.cast<int>()); return true; }
82    static handle cast(const MoveOrCopyInt &m, return_value_policy r, handle p) { return pybind11::cast(m.value, r, p); }
83};
84
85template <> struct type_caster<CopyOnlyInt> {
86protected:
87    CopyOnlyInt value;
88public:
89    static constexpr auto name = _("CopyOnlyInt");
90    bool load(handle src, bool) { value = CopyOnlyInt(src.cast<int>()); return true; }
91    static handle cast(const CopyOnlyInt &m, return_value_policy r, handle p) { return pybind11::cast(m.value, r, p); }
92    static handle cast(const CopyOnlyInt *src, return_value_policy policy, handle parent) {
93        if (!src) return none().release();
94        return cast(*src, policy, parent);
95    }
96    operator CopyOnlyInt*() { return &value; }
97    operator CopyOnlyInt&() { return value; }
98    template <typename T> using cast_op_type = pybind11::detail::cast_op_type<T>;
99};
100NAMESPACE_END(detail)
101NAMESPACE_END(pybind11)
102
103TEST_SUBMODULE(copy_move_policies, m) {
104    // test_lacking_copy_ctor
105    py::class_<lacking_copy_ctor>(m, "lacking_copy_ctor")
106        .def_static("get_one", &lacking_copy_ctor::get_one,
107                    py::return_value_policy::copy);
108    // test_lacking_move_ctor
109    py::class_<lacking_move_ctor>(m, "lacking_move_ctor")
110        .def_static("get_one", &lacking_move_ctor::get_one,
111                    py::return_value_policy::move);
112
113    // test_move_and_copy_casts
114    m.def("move_and_copy_casts", [](py::object o) {
115        int r = 0;
116        r += py::cast<MoveOrCopyInt>(o).value; /* moves */
117        r += py::cast<MoveOnlyInt>(o).value; /* moves */
118        r += py::cast<CopyOnlyInt>(o).value; /* copies */
119        MoveOrCopyInt m1(py::cast<MoveOrCopyInt>(o)); /* moves */
120        MoveOnlyInt m2(py::cast<MoveOnlyInt>(o)); /* moves */
121        CopyOnlyInt m3(py::cast<CopyOnlyInt>(o)); /* copies */
122        r += m1.value + m2.value + m3.value;
123
124        return r;
125    });
126
127    // test_move_and_copy_loads
128    m.def("move_only", [](MoveOnlyInt m) { return m.value; });
129    m.def("move_or_copy", [](MoveOrCopyInt m) { return m.value; });
130    m.def("copy_only", [](CopyOnlyInt m) { return m.value; });
131    m.def("move_pair", [](std::pair<MoveOnlyInt, MoveOrCopyInt> p) {
132        return p.first.value + p.second.value;
133    });
134    m.def("move_tuple", [](std::tuple<MoveOnlyInt, MoveOrCopyInt, MoveOnlyInt> t) {
135        return std::get<0>(t).value + std::get<1>(t).value + std::get<2>(t).value;
136    });
137    m.def("copy_tuple", [](std::tuple<CopyOnlyInt, CopyOnlyInt> t) {
138        return std::get<0>(t).value + std::get<1>(t).value;
139    });
140    m.def("move_copy_nested", [](std::pair<MoveOnlyInt, std::pair<std::tuple<MoveOrCopyInt, CopyOnlyInt, std::tuple<MoveOnlyInt>>, MoveOrCopyInt>> x) {
141        return x.first.value + std::get<0>(x.second.first).value + std::get<1>(x.second.first).value +
142            std::get<0>(std::get<2>(x.second.first)).value + x.second.second.value;
143    });
144    m.def("move_and_copy_cstats", []() {
145        ConstructorStats::gc();
146        // Reset counts to 0 so that previous tests don't affect later ones:
147        auto &mc = ConstructorStats::get<MoveOrCopyInt>();
148        mc.move_assignments = mc.move_constructions = mc.copy_assignments = mc.copy_constructions = 0;
149        auto &mo = ConstructorStats::get<MoveOnlyInt>();
150        mo.move_assignments = mo.move_constructions = mo.copy_assignments = mo.copy_constructions = 0;
151        auto &co = ConstructorStats::get<CopyOnlyInt>();
152        co.move_assignments = co.move_constructions = co.copy_assignments = co.copy_constructions = 0;
153        py::dict d;
154        d["MoveOrCopyInt"] = py::cast(mc, py::return_value_policy::reference);
155        d["MoveOnlyInt"] = py::cast(mo, py::return_value_policy::reference);
156        d["CopyOnlyInt"] = py::cast(co, py::return_value_policy::reference);
157        return d;
158    });
159#ifdef PYBIND11_HAS_OPTIONAL
160    // test_move_and_copy_load_optional
161    m.attr("has_optional") = true;
162    m.def("move_optional", [](std::optional<MoveOnlyInt> o) {
163        return o->value;
164    });
165    m.def("move_or_copy_optional", [](std::optional<MoveOrCopyInt> o) {
166        return o->value;
167    });
168    m.def("copy_optional", [](std::optional<CopyOnlyInt> o) {
169        return o->value;
170    });
171    m.def("move_optional_tuple", [](std::optional<std::tuple<MoveOrCopyInt, MoveOnlyInt, CopyOnlyInt>> x) {
172        return std::get<0>(*x).value + std::get<1>(*x).value + std::get<2>(*x).value;
173    });
174#else
175    m.attr("has_optional") = false;
176#endif
177
178    // #70 compilation issue if operator new is not public
179    struct PrivateOpNew {
180        int value = 1;
181    private:
182#if defined(_MSC_VER)
183#  pragma warning(disable: 4822) // warning C4822: local class member function does not have a body
184#endif
185        void *operator new(size_t bytes);
186    };
187    py::class_<PrivateOpNew>(m, "PrivateOpNew").def_readonly("value", &PrivateOpNew::value);
188    m.def("private_op_new_value", []() { return PrivateOpNew(); });
189    m.def("private_op_new_reference", []() -> const PrivateOpNew & {
190        static PrivateOpNew x{};
191        return x;
192    }, py::return_value_policy::reference);
193
194    // test_move_fallback
195    // #389: rvp::move should fall-through to copy on non-movable objects
196    struct MoveIssue1 {
197        int v;
198        MoveIssue1(int v) : v{v} {}
199        MoveIssue1(const MoveIssue1 &c) = default;
200        MoveIssue1(MoveIssue1 &&) = delete;
201    };
202    py::class_<MoveIssue1>(m, "MoveIssue1").def(py::init<int>()).def_readwrite("value", &MoveIssue1::v);
203
204    struct MoveIssue2 {
205        int v;
206        MoveIssue2(int v) : v{v} {}
207        MoveIssue2(MoveIssue2 &&) = default;
208    };
209    py::class_<MoveIssue2>(m, "MoveIssue2").def(py::init<int>()).def_readwrite("value", &MoveIssue2::v);
210
211    m.def("get_moveissue1", [](int i) { return new MoveIssue1(i); }, py::return_value_policy::move);
212    m.def("get_moveissue2", [](int i) { return MoveIssue2(i); }, py::return_value_policy::move);
213}
214