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test_smart_ptr.cpp
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/*
tests/test_smart_ptr.cpp -- binding classes with custom reference counting,
implicit conversions between types
Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
All rights reserved. Use of this source code is governed by a
BSD-style license that can be found in the LICENSE file.
*/
#if defined(_MSC_VER) && _MSC_VER < 1910
# pragma warning(disable: 4702) // unreachable code in system header
#endif
#include "pybind11_tests.h"
#include "object.h"
// Make pybind aware of the ref-counted wrapper type (s):
// ref<T> is a wrapper for 'Object' which uses intrusive reference counting
// It is always possible to construct a ref<T> from an Object* pointer without
// possible inconsistencies, hence the 'true' argument at the end.
PYBIND11_DECLARE_HOLDER_TYPE(T, ref<T>, true);
// Make pybind11 aware of the non-standard getter member function
namespace pybind11 { namespace detail {
template <typename T>
struct holder_helper<ref<T>> {
static const T *get(const ref<T> &p) { return p.get_ptr(); }
};
}}
// The following is not required anymore for std::shared_ptr, but it should compile without error:
PYBIND11_DECLARE_HOLDER_TYPE(T, std::shared_ptr<T>);
// This is just a wrapper around unique_ptr, but with extra fields to deliberately bloat up the
// holder size to trigger the non-simple-layout internal instance layout for single inheritance with
// large holder type:
template <typename T> class huge_unique_ptr {
std::unique_ptr<T> ptr;
uint64_t padding[10];
public:
huge_unique_ptr(T *p) : ptr(p) {};
T *get() { return ptr.get(); }
};
PYBIND11_DECLARE_HOLDER_TYPE(T, huge_unique_ptr<T>);
// Simple custom holder that works like unique_ptr
template <typename T>
class custom_unique_ptr {
std::unique_ptr<T> impl;
public:
custom_unique_ptr(T* p) : impl(p) { }
T* get() const { return impl.get(); }
T* release_ptr() { return impl.release(); }
};
PYBIND11_DECLARE_HOLDER_TYPE(T, custom_unique_ptr<T>);
// Simple custom holder that works like shared_ptr and has operator& overload
// To obtain address of an instance of this holder pybind should use std::addressof
// Attempt to get address via operator& may leads to segmentation fault
template <typename T>
class shared_ptr_with_addressof_operator {
std::shared_ptr<T> impl;
public:
shared_ptr_with_addressof_operator( ) = default;
shared_ptr_with_addressof_operator(T* p) : impl(p) { }
T* get() const { return impl.get(); }
T** operator&() { throw std::logic_error("Call of overloaded operator& is not expected"); }
};
PYBIND11_DECLARE_HOLDER_TYPE(T, shared_ptr_with_addressof_operator<T>);
// Simple custom holder that works like unique_ptr and has operator& overload
// To obtain address of an instance of this holder pybind should use std::addressof
// Attempt to get address via operator& may leads to segmentation fault
template <typename T>
class unique_ptr_with_addressof_operator {
std::unique_ptr<T> impl;
public:
unique_ptr_with_addressof_operator() = default;
unique_ptr_with_addressof_operator(T* p) : impl(p) { }
T* get() const { return impl.get(); }
T* release_ptr() { return impl.release(); }
T** operator&() { throw std::logic_error("Call of overloaded operator& is not expected"); }
};
PYBIND11_DECLARE_HOLDER_TYPE(T, unique_ptr_with_addressof_operator<T>);
TEST_SUBMODULE(smart_ptr, m) {
// test_smart_ptr
// Object implementation in `object.h`
py::class_<Object, ref<Object>> obj(m, "Object");
obj.def("getRefCount", &Object::getRefCount);
// Custom object with builtin reference counting (see 'object.h' for the implementation)
class MyObject1 : public Object {
public:
MyObject1(int value) : value(value) { print_created(this, toString()); }
std::string toString() const { return "MyObject1[" + std::to_string(value) + "]"; }
protected:
virtual ~MyObject1() { print_destroyed(this); }
private:
int value;
};
py::class_<MyObject1, ref<MyObject1>>(m, "MyObject1", obj)
.def(py::init<int>());
py::implicitly_convertible<py::int_, MyObject1>();
m.def("make_object_1", []() -> Object * { return new MyObject1(1); });
m.def("make_object_2", []() -> ref<Object> { return new MyObject1(2); });
m.def("make_myobject1_1", []() -> MyObject1 * { return new MyObject1(4); });
m.def("make_myobject1_2", []() -> ref<MyObject1> { return new MyObject1(5); });
m.def("print_object_1", [](const Object *obj) { py::print(obj->toString()); });
m.def("print_object_2", [](ref<Object> obj) { py::print(obj->toString()); });
m.def("print_object_3", [](const ref<Object> &obj) { py::print(obj->toString()); });
m.def("print_object_4", [](const ref<Object> *obj) { py::print((*obj)->toString()); });
m.def("print_myobject1_1", [](const MyObject1 *obj) { py::print(obj->toString()); });
m.def("print_myobject1_2", [](ref<MyObject1> obj) { py::print(obj->toString()); });
m.def("print_myobject1_3", [](const ref<MyObject1> &obj) { py::print(obj->toString()); });
m.def("print_myobject1_4", [](const ref<MyObject1> *obj) { py::print((*obj)->toString()); });
// Expose constructor stats for the ref type
m.def("cstats_ref", &ConstructorStats::get<ref_tag>);
// Object managed by a std::shared_ptr<>
class MyObject2 {
public:
MyObject2(const MyObject2 &) = default;
MyObject2(int value) : value(value) { print_created(this, toString()); }
std::string toString() const { return "MyObject2[" + std::to_string(value) + "]"; }
virtual ~MyObject2() { print_destroyed(this); }
private:
int value;
};
py::class_<MyObject2, std::shared_ptr<MyObject2>>(m, "MyObject2")
.def(py::init<int>());
m.def("make_myobject2_1", []() { return new MyObject2(6); });
m.def("make_myobject2_2", []() { return std::make_shared<MyObject2>(7); });
m.def("print_myobject2_1", [](const MyObject2 *obj) { py::print(obj->toString()); });
m.def("print_myobject2_2", [](std::shared_ptr<MyObject2> obj) { py::print(obj->toString()); });
m.def("print_myobject2_3", [](const std::shared_ptr<MyObject2> &obj) { py::print(obj->toString()); });
m.def("print_myobject2_4", [](const std::shared_ptr<MyObject2> *obj) { py::print((*obj)->toString()); });
// Object managed by a std::shared_ptr<>, additionally derives from std::enable_shared_from_this<>
class MyObject3 : public std::enable_shared_from_this<MyObject3> {
public:
MyObject3(const MyObject3 &) = default;
MyObject3(int value) : value(value) { print_created(this, toString()); }
std::string toString() const { return "MyObject3[" + std::to_string(value) + "]"; }
virtual ~MyObject3() { print_destroyed(this); }
private:
int value;
};
py::class_<MyObject3, std::shared_ptr<MyObject3>>(m, "MyObject3")
.def(py::init<int>());
m.def("make_myobject3_1", []() { return new MyObject3(8); });
m.def("make_myobject3_2", []() { return std::make_shared<MyObject3>(9); });
m.def("print_myobject3_1", [](const MyObject3 *obj) { py::print(obj->toString()); });
m.def("print_myobject3_2", [](std::shared_ptr<MyObject3> obj) { py::print(obj->toString()); });
m.def("print_myobject3_3", [](const std::shared_ptr<MyObject3> &obj) { py::print(obj->toString()); });
m.def("print_myobject3_4", [](const std::shared_ptr<MyObject3> *obj) { py::print((*obj)->toString()); });
// test_smart_ptr_refcounting
m.def("test_object1_refcounting", []() {
ref<MyObject1> o = new MyObject1(0);
bool good = o->getRefCount() == 1;
py::object o2 = py::cast(o, py::return_value_policy::reference);
// always request (partial) ownership for objects with intrusive
// reference counting even when using the 'reference' RVP
good &= o->getRefCount() == 2;
return good;
});
// test_unique_nodelete
// Object with a private destructor
class MyObject4 {
public:
MyObject4(int value) : value{value} { print_created(this); }
int value;
private:
~MyObject4() { print_destroyed(this); }
};
py::class_<MyObject4, std::unique_ptr<MyObject4, py::nodelete>>(m, "MyObject4")
.def(py::init<int>())
.def_readwrite("value", &MyObject4::value);
// test_unique_deleter
// Object with std::unique_ptr<T, D> where D is not matching the base class
// Object with a protected destructor
class MyObject4a {
public:
MyObject4a(int i) {
value = i;
print_created(this);
};
int value;
protected:
virtual ~MyObject4a() { print_destroyed(this); }
};
py::class_<MyObject4a, std::unique_ptr<MyObject4a, py::nodelete>>(m, "MyObject4a")
.def(py::init<int>())
.def_readwrite("value", &MyObject4a::value);
// Object derived but with public destructor and no Deleter in default holder
class MyObject4b : public MyObject4a {
public:
MyObject4b(int i) : MyObject4a(i) { print_created(this); }
~MyObject4b() { print_destroyed(this); }
};
py::class_<MyObject4b, MyObject4a>(m, "MyObject4b")
.def(py::init<int>());
// test_large_holder
class MyObject5 { // managed by huge_unique_ptr
public:
MyObject5(int value) : value{value} { print_created(this); }
~MyObject5() { print_destroyed(this); }
int value;
};
py::class_<MyObject5, huge_unique_ptr<MyObject5>>(m, "MyObject5")
.def(py::init<int>())
.def_readwrite("value", &MyObject5::value);
// test_shared_ptr_and_references
struct SharedPtrRef {
struct A {
A() { print_created(this); }
A(const A &) { print_copy_created(this); }
A(A &&) { print_move_created(this); }
~A() { print_destroyed(this); }
};
A value = {};
std::shared_ptr<A> shared = std::make_shared<A>();
};
using A = SharedPtrRef::A;
py::class_<A, std::shared_ptr<A>>(m, "A");
py::class_<SharedPtrRef>(m, "SharedPtrRef")
.def(py::init<>())
.def_readonly("ref", &SharedPtrRef::value)
.def_property_readonly("copy", [](const SharedPtrRef &s) { return s.value; },
py::return_value_policy::copy)
.def_readonly("holder_ref", &SharedPtrRef::shared)
.def_property_readonly("holder_copy", [](const SharedPtrRef &s) { return s.shared; },
py::return_value_policy::copy)
.def("set_ref", [](SharedPtrRef &, const A &) { return true; })
.def("set_holder", [](SharedPtrRef &, std::shared_ptr<A>) { return true; });
// test_shared_ptr_from_this_and_references
struct SharedFromThisRef {
struct B : std::enable_shared_from_this<B> {
B() { print_created(this); }
B(const B &) : std::enable_shared_from_this<B>() { print_copy_created(this); }
B(B &&) : std::enable_shared_from_this<B>() { print_move_created(this); }
~B() { print_destroyed(this); }
};
B value = {};
std::shared_ptr<B> shared = std::make_shared<B>();
};
using B = SharedFromThisRef::B;
py::class_<B, std::shared_ptr<B>>(m, "B");
py::class_<SharedFromThisRef>(m, "SharedFromThisRef")
.def(py::init<>())
.def_readonly("bad_wp", &SharedFromThisRef::value)
.def_property_readonly("ref", [](const SharedFromThisRef &s) -> const B & { return *s.shared; })
.def_property_readonly("copy", [](const SharedFromThisRef &s) { return s.value; },
py::return_value_policy::copy)
.def_readonly("holder_ref", &SharedFromThisRef::shared)
.def_property_readonly("holder_copy", [](const SharedFromThisRef &s) { return s.shared; },
py::return_value_policy::copy)
.def("set_ref", [](SharedFromThisRef &, const B &) { return true; })
.def("set_holder", [](SharedFromThisRef &, std::shared_ptr<B>) { return true; });
// Issue #865: shared_from_this doesn't work with virtual inheritance
struct SharedFromThisVBase : std::enable_shared_from_this<SharedFromThisVBase> {
SharedFromThisVBase() = default;
SharedFromThisVBase(const SharedFromThisVBase &) = default;
virtual ~SharedFromThisVBase() = default;
};
struct SharedFromThisVirt : virtual SharedFromThisVBase {};
static std::shared_ptr<SharedFromThisVirt> sft(new SharedFromThisVirt());
py::class_<SharedFromThisVirt, std::shared_ptr<SharedFromThisVirt>>(m, "SharedFromThisVirt")
.def_static("get", []() { return sft.get(); });
// test_move_only_holder
struct C {
C() { print_created(this); }
~C() { print_destroyed(this); }
};
py::class_<C, custom_unique_ptr<C>>(m, "TypeWithMoveOnlyHolder")
.def_static("make", []() { return custom_unique_ptr<C>(new C); });
// test_holder_with_addressof_operator
struct TypeForHolderWithAddressOf {
TypeForHolderWithAddressOf() { print_created(this); }
TypeForHolderWithAddressOf(const TypeForHolderWithAddressOf &) { print_copy_created(this); }
TypeForHolderWithAddressOf(TypeForHolderWithAddressOf &&) { print_move_created(this); }
~TypeForHolderWithAddressOf() { print_destroyed(this); }
std::string toString() const {
return "TypeForHolderWithAddressOf[" + std::to_string(value) + "]";
}
int value = 42;
};
using HolderWithAddressOf = shared_ptr_with_addressof_operator<TypeForHolderWithAddressOf>;
py::class_<TypeForHolderWithAddressOf, HolderWithAddressOf>(m, "TypeForHolderWithAddressOf")
.def_static("make", []() { return HolderWithAddressOf(new TypeForHolderWithAddressOf); })
.def("get", [](const HolderWithAddressOf &self) { return self.get(); })
.def("print_object_1", [](const TypeForHolderWithAddressOf *obj) { py::print(obj->toString()); })
.def("print_object_2", [](HolderWithAddressOf obj) { py::print(obj.get()->toString()); })
.def("print_object_3", [](const HolderWithAddressOf &obj) { py::print(obj.get()->toString()); })
.def("print_object_4", [](const HolderWithAddressOf *obj) { py::print((*obj).get()->toString()); });
// test_move_only_holder_with_addressof_operator
struct TypeForMoveOnlyHolderWithAddressOf {
TypeForMoveOnlyHolderWithAddressOf(int value) : value{value} { print_created(this); }
~TypeForMoveOnlyHolderWithAddressOf() { print_destroyed(this); }
std::string toString() const {
return "MoveOnlyHolderWithAddressOf[" + std::to_string(value) + "]";
}
int value;
};
using MoveOnlyHolderWithAddressOf = unique_ptr_with_addressof_operator<TypeForMoveOnlyHolderWithAddressOf>;
py::class_<TypeForMoveOnlyHolderWithAddressOf, MoveOnlyHolderWithAddressOf>(m, "TypeForMoveOnlyHolderWithAddressOf")
.def_static("make", []() { return MoveOnlyHolderWithAddressOf(new TypeForMoveOnlyHolderWithAddressOf(0)); })
.def_readwrite("value", &TypeForMoveOnlyHolderWithAddressOf::value)
.def("print_object", [](const TypeForMoveOnlyHolderWithAddressOf *obj) { py::print(obj->toString()); });
// test_smart_ptr_from_default
struct HeldByDefaultHolder { };
py::class_<HeldByDefaultHolder>(m, "HeldByDefaultHolder")
.def(py::init<>())
.def_static("load_shared_ptr", [](std::shared_ptr<HeldByDefaultHolder>) {});
// test_shared_ptr_gc
// #187: issue involving std::shared_ptr<> return value policy & garbage collection
struct ElementBase { virtual void foo() { } /* Force creation of virtual table */ };
py::class_<ElementBase, std::shared_ptr<ElementBase>>(m, "ElementBase");
struct ElementA : ElementBase {
ElementA(int v) : v(v) { }
int value() { return v; }
int v;
};
py::class_<ElementA, ElementBase, std::shared_ptr<ElementA>>(m, "ElementA")
.def(py::init<int>())
.def("value", &ElementA::value);
struct ElementList {
void add(std::shared_ptr<ElementBase> e) { l.push_back(e); }
std::vector<std::shared_ptr<ElementBase>> l;
};
py::class_<ElementList, std::shared_ptr<ElementList>>(m, "ElementList")
.def(py::init<>())
.def("add", &ElementList::add)
.def("get", [](ElementList &el) {
py::list list;
for (auto &e : el.l)
list.append(py::cast(e));
return list;
});
}

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