test_smart_ptr.cpp revision 12037:d28054ac6ec9 
1/*
2    tests/test_smart_ptr.cpp -- binding classes with custom reference counting,
3    implicit conversions between types
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 "object.h"
13
14/// Custom object with builtin reference counting (see 'object.h' for the implementation)
15class MyObject1 : public Object {
16public:
17    MyObject1(int value) : value(value) {
18        print_created(this, toString());
19    }
20
21    std::string toString() const {
22        return "MyObject1[" + std::to_string(value) + "]";
23    }
24
25protected:
26    virtual ~MyObject1() {
27        print_destroyed(this);
28    }
29
30private:
31    int value;
32};
33
34/// Object managed by a std::shared_ptr<>
35class MyObject2 {
36public:
37    MyObject2(int value) : value(value) {
38        print_created(this, toString());
39    }
40
41    std::string toString() const {
42        return "MyObject2[" + std::to_string(value) + "]";
43    }
44
45    virtual ~MyObject2() {
46        print_destroyed(this);
47    }
48
49private:
50    int value;
51};
52
53/// Object managed by a std::shared_ptr<>, additionally derives from std::enable_shared_from_this<>
54class MyObject3 : public std::enable_shared_from_this<MyObject3> {
55public:
56    MyObject3(int value) : value(value) {
57        print_created(this, toString());
58    }
59
60    std::string toString() const {
61        return "MyObject3[" + std::to_string(value) + "]";
62    }
63
64    virtual ~MyObject3() {
65        print_destroyed(this);
66    }
67
68private:
69    int value;
70};
71
72class MyObject4 {
73public:
74    MyObject4(int value) : value{value} {
75        print_created(this);
76    }
77    int value;
78private:
79    ~MyObject4() {
80        print_destroyed(this);
81    }
82};
83
84/// Make pybind aware of the ref-counted wrapper type (s)
85
86// ref<T> is a wrapper for 'Object' which uses intrusive reference counting
87// It is always possible to construct a ref<T> from an Object* pointer without
88// possible incosistencies, hence the 'true' argument at the end.
89PYBIND11_DECLARE_HOLDER_TYPE(T, ref<T>, true);
90PYBIND11_DECLARE_HOLDER_TYPE(T, std::shared_ptr<T>); // Not required any more for std::shared_ptr,
91                                                     // but it should compile without error
92
93// Make pybind11 aware of the non-standard getter member function
94namespace pybind11 { namespace detail {
95    template <typename T>
96    struct holder_helper<ref<T>> {
97        static const T *get(const ref<T> &p) { return p.get_ptr(); }
98    };
99}}
100
101Object *make_object_1() { return new MyObject1(1); }
102ref<Object> make_object_2() { return new MyObject1(2); }
103
104MyObject1 *make_myobject1_1() { return new MyObject1(4); }
105ref<MyObject1> make_myobject1_2() { return new MyObject1(5); }
106
107MyObject2 *make_myobject2_1() { return new MyObject2(6); }
108std::shared_ptr<MyObject2> make_myobject2_2() { return std::make_shared<MyObject2>(7); }
109
110MyObject3 *make_myobject3_1() { return new MyObject3(8); }
111std::shared_ptr<MyObject3> make_myobject3_2() { return std::make_shared<MyObject3>(9); }
112
113void print_object_1(const Object *obj) { py::print(obj->toString()); }
114void print_object_2(ref<Object> obj) { py::print(obj->toString()); }
115void print_object_3(const ref<Object> &obj) { py::print(obj->toString()); }
116void print_object_4(const ref<Object> *obj) { py::print((*obj)->toString()); }
117
118void print_myobject1_1(const MyObject1 *obj) { py::print(obj->toString()); }
119void print_myobject1_2(ref<MyObject1> obj) { py::print(obj->toString()); }
120void print_myobject1_3(const ref<MyObject1> &obj) { py::print(obj->toString()); }
121void print_myobject1_4(const ref<MyObject1> *obj) { py::print((*obj)->toString()); }
122
123void print_myobject2_1(const MyObject2 *obj) { py::print(obj->toString()); }
124void print_myobject2_2(std::shared_ptr<MyObject2> obj) { py::print(obj->toString()); }
125void print_myobject2_3(const std::shared_ptr<MyObject2> &obj) { py::print(obj->toString()); }
126void print_myobject2_4(const std::shared_ptr<MyObject2> *obj) { py::print((*obj)->toString()); }
127
128void print_myobject3_1(const MyObject3 *obj) { py::print(obj->toString()); }
129void print_myobject3_2(std::shared_ptr<MyObject3> obj) { py::print(obj->toString()); }
130void print_myobject3_3(const std::shared_ptr<MyObject3> &obj) { py::print(obj->toString()); }
131void print_myobject3_4(const std::shared_ptr<MyObject3> *obj) { py::print((*obj)->toString()); }
132
133test_initializer smart_ptr([](py::module &m) {
134    py::class_<Object, ref<Object>> obj(m, "Object");
135    obj.def("getRefCount", &Object::getRefCount);
136
137    py::class_<MyObject1, ref<MyObject1>>(m, "MyObject1", obj)
138        .def(py::init<int>());
139
140    m.def("test_object1_refcounting",
141        []() -> bool {
142            ref<MyObject1> o = new MyObject1(0);
143            bool good = o->getRefCount() == 1;
144            py::object o2 = py::cast(o, py::return_value_policy::reference);
145            // always request (partial) ownership for objects with intrusive
146            // reference counting even when using the 'reference' RVP
147            good &= o->getRefCount() == 2;
148            return good;
149        }
150    );
151
152    m.def("make_object_1", &make_object_1);
153    m.def("make_object_2", &make_object_2);
154    m.def("make_myobject1_1", &make_myobject1_1);
155    m.def("make_myobject1_2", &make_myobject1_2);
156    m.def("print_object_1", &print_object_1);
157    m.def("print_object_2", &print_object_2);
158    m.def("print_object_3", &print_object_3);
159    m.def("print_object_4", &print_object_4);
160    m.def("print_myobject1_1", &print_myobject1_1);
161    m.def("print_myobject1_2", &print_myobject1_2);
162    m.def("print_myobject1_3", &print_myobject1_3);
163    m.def("print_myobject1_4", &print_myobject1_4);
164
165    py::class_<MyObject2, std::shared_ptr<MyObject2>>(m, "MyObject2")
166        .def(py::init<int>());
167    m.def("make_myobject2_1", &make_myobject2_1);
168    m.def("make_myobject2_2", &make_myobject2_2);
169    m.def("print_myobject2_1", &print_myobject2_1);
170    m.def("print_myobject2_2", &print_myobject2_2);
171    m.def("print_myobject2_3", &print_myobject2_3);
172    m.def("print_myobject2_4", &print_myobject2_4);
173
174    py::class_<MyObject3, std::shared_ptr<MyObject3>>(m, "MyObject3")
175        .def(py::init<int>());
176    m.def("make_myobject3_1", &make_myobject3_1);
177    m.def("make_myobject3_2", &make_myobject3_2);
178    m.def("print_myobject3_1", &print_myobject3_1);
179    m.def("print_myobject3_2", &print_myobject3_2);
180    m.def("print_myobject3_3", &print_myobject3_3);
181    m.def("print_myobject3_4", &print_myobject3_4);
182
183    py::class_<MyObject4, std::unique_ptr<MyObject4, py::nodelete>>(m, "MyObject4")
184        .def(py::init<int>())
185        .def_readwrite("value", &MyObject4::value);
186
187    py::implicitly_convertible<py::int_, MyObject1>();
188
189    // Expose constructor stats for the ref type
190    m.def("cstats_ref", &ConstructorStats::get<ref_tag>);
191});
192
193struct SharedPtrRef {
194    struct A {
195        A() { print_created(this); }
196        A(const A &) { print_copy_created(this); }
197        A(A &&) { print_move_created(this); }
198        ~A() { print_destroyed(this); }
199    };
200
201    A value = {};
202    std::shared_ptr<A> shared = std::make_shared<A>();
203};
204
205struct SharedFromThisRef {
206    struct B : std::enable_shared_from_this<B> {
207        B() { print_created(this); }
208        B(const B &) : std::enable_shared_from_this<B>() { print_copy_created(this); }
209        B(B &&) : std::enable_shared_from_this<B>() { print_move_created(this); }
210        ~B() { print_destroyed(this); }
211    };
212
213    B value = {};
214    std::shared_ptr<B> shared = std::make_shared<B>();
215};
216
217template <typename T>
218class CustomUniquePtr {
219    std::unique_ptr<T> impl;
220
221public:
222    CustomUniquePtr(T* p) : impl(p) { }
223    T* get() const { return impl.get(); }
224    T* release_ptr() { return impl.release(); }
225};
226
227PYBIND11_DECLARE_HOLDER_TYPE(T, CustomUniquePtr<T>);
228
229test_initializer smart_ptr_and_references([](py::module &pm) {
230    auto m = pm.def_submodule("smart_ptr");
231
232    using A = SharedPtrRef::A;
233    py::class_<A, std::shared_ptr<A>>(m, "A");
234
235    py::class_<SharedPtrRef>(m, "SharedPtrRef")
236        .def(py::init<>())
237        .def_readonly("ref", &SharedPtrRef::value)
238        .def_property_readonly("copy", [](const SharedPtrRef &s) { return s.value; },
239                               py::return_value_policy::copy)
240        .def_readonly("holder_ref", &SharedPtrRef::shared)
241        .def_property_readonly("holder_copy", [](const SharedPtrRef &s) { return s.shared; },
242                               py::return_value_policy::copy)
243        .def("set_ref", [](SharedPtrRef &, const A &) { return true; })
244        .def("set_holder", [](SharedPtrRef &, std::shared_ptr<A>) { return true; });
245
246    using B = SharedFromThisRef::B;
247    py::class_<B, std::shared_ptr<B>>(m, "B");
248
249    py::class_<SharedFromThisRef>(m, "SharedFromThisRef")
250        .def(py::init<>())
251        .def_readonly("bad_wp", &SharedFromThisRef::value)
252        .def_property_readonly("ref", [](const SharedFromThisRef &s) -> const B & { return *s.shared; })
253        .def_property_readonly("copy", [](const SharedFromThisRef &s) { return s.value; },
254                               py::return_value_policy::copy)
255        .def_readonly("holder_ref", &SharedFromThisRef::shared)
256        .def_property_readonly("holder_copy", [](const SharedFromThisRef &s) { return s.shared; },
257                               py::return_value_policy::copy)
258        .def("set_ref", [](SharedFromThisRef &, const B &) { return true; })
259        .def("set_holder", [](SharedFromThisRef &, std::shared_ptr<B>) { return true; });
260
261    struct C {
262        C() { print_created(this); }
263        ~C() { print_destroyed(this); }
264    };
265
266    py::class_<C, CustomUniquePtr<C>>(m, "TypeWithMoveOnlyHolder")
267        .def_static("make", []() { return CustomUniquePtr<C>(new C); });
268
269    struct HeldByDefaultHolder { };
270
271    py::class_<HeldByDefaultHolder>(m, "HeldByDefaultHolder")
272        .def(py::init<>())
273        .def_static("load_shared_ptr", [](std::shared_ptr<HeldByDefaultHolder>) {});
274});
275