test_multiple_inheritance.cpp revision 14299:2fbea9df56d2 
1/*
2    tests/test_multiple_inheritance.cpp -- multiple inheritance,
3    implicit MI casts
4
5    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
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
14// Many bases for testing that multiple inheritance from many classes (i.e. requiring extra
15// space for holder constructed flags) works.
16template <int N> struct BaseN {
17    BaseN(int i) : i(i) { }
18    int i;
19};
20
21// test_mi_static_properties
22struct Vanilla {
23    std::string vanilla() { return "Vanilla"; };
24};
25struct WithStatic1 {
26    static std::string static_func1() { return "WithStatic1"; };
27    static int static_value1;
28};
29struct WithStatic2 {
30    static std::string static_func2() { return "WithStatic2"; };
31    static int static_value2;
32};
33struct VanillaStaticMix1 : Vanilla, WithStatic1, WithStatic2 {
34    static std::string static_func() { return "VanillaStaticMix1"; }
35    static int static_value;
36};
37struct VanillaStaticMix2 : WithStatic1, Vanilla, WithStatic2 {
38    static std::string static_func() { return "VanillaStaticMix2"; }
39    static int static_value;
40};
41int WithStatic1::static_value1 = 1;
42int WithStatic2::static_value2 = 2;
43int VanillaStaticMix1::static_value = 12;
44int VanillaStaticMix2::static_value = 12;
45
46TEST_SUBMODULE(multiple_inheritance, m) {
47
48    // test_multiple_inheritance_mix1
49    // test_multiple_inheritance_mix2
50    struct Base1 {
51        Base1(int i) : i(i) { }
52        int foo() { return i; }
53        int i;
54    };
55    py::class_<Base1> b1(m, "Base1");
56    b1.def(py::init<int>())
57      .def("foo", &Base1::foo);
58
59    struct Base2 {
60        Base2(int i) : i(i) { }
61        int bar() { return i; }
62        int i;
63    };
64    py::class_<Base2> b2(m, "Base2");
65    b2.def(py::init<int>())
66      .def("bar", &Base2::bar);
67
68
69    // test_multiple_inheritance_cpp
70    struct Base12 : Base1, Base2 {
71        Base12(int i, int j) : Base1(i), Base2(j) { }
72    };
73    struct MIType : Base12 {
74        MIType(int i, int j) : Base12(i, j) { }
75    };
76    py::class_<Base12, Base1, Base2>(m, "Base12");
77    py::class_<MIType, Base12>(m, "MIType")
78        .def(py::init<int, int>());
79
80
81    // test_multiple_inheritance_python_many_bases
82    #define PYBIND11_BASEN(N) py::class_<BaseN<N>>(m, "BaseN" #N).def(py::init<int>()).def("f" #N, [](BaseN<N> &b) { return b.i + N; })
83    PYBIND11_BASEN( 1); PYBIND11_BASEN( 2); PYBIND11_BASEN( 3); PYBIND11_BASEN( 4);
84    PYBIND11_BASEN( 5); PYBIND11_BASEN( 6); PYBIND11_BASEN( 7); PYBIND11_BASEN( 8);
85    PYBIND11_BASEN( 9); PYBIND11_BASEN(10); PYBIND11_BASEN(11); PYBIND11_BASEN(12);
86    PYBIND11_BASEN(13); PYBIND11_BASEN(14); PYBIND11_BASEN(15); PYBIND11_BASEN(16);
87    PYBIND11_BASEN(17);
88
89    // Uncommenting this should result in a compile time failure (MI can only be specified via
90    // template parameters because pybind has to know the types involved; see discussion in #742 for
91    // details).
92//    struct Base12v2 : Base1, Base2 {
93//        Base12v2(int i, int j) : Base1(i), Base2(j) { }
94//    };
95//    py::class_<Base12v2>(m, "Base12v2", b1, b2)
96//        .def(py::init<int, int>());
97
98
99    // test_multiple_inheritance_virtbase
100    // Test the case where not all base classes are specified, and where pybind11 requires the
101    // py::multiple_inheritance flag to perform proper casting between types.
102    struct Base1a {
103        Base1a(int i) : i(i) { }
104        int foo() { return i; }
105        int i;
106    };
107    py::class_<Base1a, std::shared_ptr<Base1a>>(m, "Base1a")
108        .def(py::init<int>())
109        .def("foo", &Base1a::foo);
110
111    struct Base2a {
112        Base2a(int i) : i(i) { }
113        int bar() { return i; }
114        int i;
115    };
116    py::class_<Base2a, std::shared_ptr<Base2a>>(m, "Base2a")
117        .def(py::init<int>())
118        .def("bar", &Base2a::bar);
119
120    struct Base12a : Base1a, Base2a {
121        Base12a(int i, int j) : Base1a(i), Base2a(j) { }
122    };
123    py::class_<Base12a, /* Base1 missing */ Base2a,
124               std::shared_ptr<Base12a>>(m, "Base12a", py::multiple_inheritance())
125        .def(py::init<int, int>());
126
127    m.def("bar_base2a", [](Base2a *b) { return b->bar(); });
128    m.def("bar_base2a_sharedptr", [](std::shared_ptr<Base2a> b) { return b->bar(); });
129
130    // test_mi_unaligned_base
131    // test_mi_base_return
132    // Issue #801: invalid casting to derived type with MI bases
133    struct I801B1 { int a = 1; I801B1() = default; I801B1(const I801B1 &) = default; virtual ~I801B1() = default; };
134    struct I801B2 { int b = 2; I801B2() = default; I801B2(const I801B2 &) = default; virtual ~I801B2() = default; };
135    struct I801C : I801B1, I801B2 {};
136    struct I801D : I801C {}; // Indirect MI
137    // Unregistered classes:
138    struct I801B3 { int c = 3; virtual ~I801B3() = default; };
139    struct I801E : I801B3, I801D {};
140
141    py::class_<I801B1, std::shared_ptr<I801B1>>(m, "I801B1").def(py::init<>()).def_readonly("a", &I801B1::a);
142    py::class_<I801B2, std::shared_ptr<I801B2>>(m, "I801B2").def(py::init<>()).def_readonly("b", &I801B2::b);
143    py::class_<I801C, I801B1, I801B2, std::shared_ptr<I801C>>(m, "I801C").def(py::init<>());
144    py::class_<I801D, I801C, std::shared_ptr<I801D>>(m, "I801D").def(py::init<>());
145
146    // Two separate issues here: first, we want to recognize a pointer to a base type as being a
147    // known instance even when the pointer value is unequal (i.e. due to a non-first
148    // multiple-inheritance base class):
149    m.def("i801b1_c", [](I801C *c) { return static_cast<I801B1 *>(c); });
150    m.def("i801b2_c", [](I801C *c) { return static_cast<I801B2 *>(c); });
151    m.def("i801b1_d", [](I801D *d) { return static_cast<I801B1 *>(d); });
152    m.def("i801b2_d", [](I801D *d) { return static_cast<I801B2 *>(d); });
153
154    // Second, when returned a base class pointer to a derived instance, we cannot assume that the
155    // pointer is `reinterpret_cast`able to the derived pointer because, like above, the base class
156    // pointer could be offset.
157    m.def("i801c_b1", []() -> I801B1 * { return new I801C(); });
158    m.def("i801c_b2", []() -> I801B2 * { return new I801C(); });
159    m.def("i801d_b1", []() -> I801B1 * { return new I801D(); });
160    m.def("i801d_b2", []() -> I801B2 * { return new I801D(); });
161
162    // Return a base class pointer to a pybind-registered type when the actual derived type
163    // isn't pybind-registered (and uses multiple-inheritance to offset the pybind base)
164    m.def("i801e_c", []() -> I801C * { return new I801E(); });
165    m.def("i801e_b2", []() -> I801B2 * { return new I801E(); });
166
167
168    // test_mi_static_properties
169    py::class_<Vanilla>(m, "Vanilla")
170        .def(py::init<>())
171        .def("vanilla", &Vanilla::vanilla);
172
173    py::class_<WithStatic1>(m, "WithStatic1")
174        .def(py::init<>())
175        .def_static("static_func1", &WithStatic1::static_func1)
176        .def_readwrite_static("static_value1", &WithStatic1::static_value1);
177
178    py::class_<WithStatic2>(m, "WithStatic2")
179        .def(py::init<>())
180        .def_static("static_func2", &WithStatic2::static_func2)
181        .def_readwrite_static("static_value2", &WithStatic2::static_value2);
182
183    py::class_<VanillaStaticMix1, Vanilla, WithStatic1, WithStatic2>(
184        m, "VanillaStaticMix1")
185        .def(py::init<>())
186        .def_static("static_func", &VanillaStaticMix1::static_func)
187        .def_readwrite_static("static_value", &VanillaStaticMix1::static_value);
188
189    py::class_<VanillaStaticMix2, WithStatic1, Vanilla, WithStatic2>(
190        m, "VanillaStaticMix2")
191        .def(py::init<>())
192        .def_static("static_func", &VanillaStaticMix2::static_func)
193        .def_readwrite_static("static_value", &VanillaStaticMix2::static_value);
194
195
196#if !defined(PYPY_VERSION)
197    struct WithDict { };
198    struct VanillaDictMix1 : Vanilla, WithDict { };
199    struct VanillaDictMix2 : WithDict, Vanilla { };
200    py::class_<WithDict>(m, "WithDict", py::dynamic_attr()).def(py::init<>());
201    py::class_<VanillaDictMix1, Vanilla, WithDict>(m, "VanillaDictMix1").def(py::init<>());
202    py::class_<VanillaDictMix2, WithDict, Vanilla>(m, "VanillaDictMix2").def(py::init<>());
203#endif
204
205    // test_diamond_inheritance
206    // Issue #959: segfault when constructing diamond inheritance instance
207    // All of these have int members so that there will be various unequal pointers involved.
208    struct B { int b; B() = default; B(const B&) = default; virtual ~B() = default; };
209    struct C0 : public virtual B { int c0; };
210    struct C1 : public virtual B { int c1; };
211    struct D : public C0, public C1 { int d; };
212    py::class_<B>(m, "B")
213        .def("b", [](B *self) { return self; });
214    py::class_<C0, B>(m, "C0")
215        .def("c0", [](C0 *self) { return self; });
216    py::class_<C1, B>(m, "C1")
217        .def("c1", [](C1 *self) { return self; });
218    py::class_<D, C0, C1>(m, "D")
219        .def(py::init<>());
220}
221