return best representation of polymorphic types (fixes #105)

This commit is contained in:
Wenzel Jakob 2016-04-13 13:45:09 +02:00
parent d40885a1e6
commit d7efa4ff7b
7 changed files with 55 additions and 4 deletions

View File

@ -121,6 +121,7 @@ set(PYBIND11_EXAMPLES
example/example13.cpp example/example13.cpp
example/example14.cpp example/example14.cpp
example/example15.cpp example/example15.cpp
example/example16.cpp
example/issues.cpp example/issues.cpp
) )

View File

@ -5,7 +5,8 @@ Changelog
1.5 (not yet released) 1.5 (not yet released)
---------------------- ----------------------
* Pickling support * For polymorphic types, use RTTI to try to return the closest type registered with pybind11.
* Pickling support for serializing and unserializing C++ instances to a byte stream in Python
* Added a variadic ``make_tuple()`` function * Added a variadic ``make_tuple()`` function
* Address a rare issue that could confuse the current virtual function dispatcher * Address a rare issue that could confuse the current virtual function dispatcher
* Documentation improvements: import issues, symbol visibility, pickling, limitations * Documentation improvements: import issues, symbol visibility, pickling, limitations

View File

@ -24,6 +24,7 @@ void init_ex12(py::module &);
void init_ex13(py::module &); void init_ex13(py::module &);
void init_ex14(py::module &); void init_ex14(py::module &);
void init_ex15(py::module &); void init_ex15(py::module &);
void init_ex16(py::module &);
void init_issues(py::module &); void init_issues(py::module &);
PYBIND11_PLUGIN(example) { PYBIND11_PLUGIN(example) {
@ -44,6 +45,7 @@ PYBIND11_PLUGIN(example) {
init_ex13(m); init_ex13(m);
init_ex14(m); init_ex14(m);
init_ex15(m); init_ex15(m);
init_ex16(m);
init_issues(m); init_issues(m);
return m.ptr(); return m.ptr();

24
example/example16.cpp Normal file
View File

@ -0,0 +1,24 @@
/*
example/example16.cpp -- automatic upcasting for polymorphic types
Copyright (c) 2015 Wenzel Jakob <wenzel@inf.ethz.ch>
All rights reserved. Use of this source code is governed by a
BSD-style license that can be found in the LICENSE file.
*/
#include "example.h"
struct BaseClass { virtual ~BaseClass() {} };
struct DerivedClass1 : BaseClass { };
struct DerivedClass2 : BaseClass { };
void init_ex16(py::module &m) {
py::class_<BaseClass>(m, "BaseClass").def(py::init<>());
py::class_<DerivedClass1>(m, "DerivedClass1").def(py::init<>());
py::class_<DerivedClass2>(m, "DerivedClass2").def(py::init<>());
m.def("return_class_1", []() -> BaseClass* { return new DerivedClass1(); });
m.def("return_class_2", []() -> BaseClass* { return new DerivedClass2(); });
m.def("return_none", []() -> BaseClass* { return nullptr; });
}

12
example/example16.py Normal file
View File

@ -0,0 +1,12 @@
from __future__ import print_function
import sys
sys.path.append('.')
from example import return_class_1
from example import return_class_2
from example import return_none
print(type(return_class_1()))
print(type(return_class_2()))
print(type(return_none()))

3
example/example16.ref Normal file
View File

@ -0,0 +1,3 @@
<class 'example.DerivedClass1'>
<class 'example.DerivedClass2'>
<type 'NoneType'>

View File

@ -137,6 +137,7 @@ public:
PYBIND11_NOINLINE static handle cast(const void *_src, return_value_policy policy, handle parent, PYBIND11_NOINLINE static handle cast(const void *_src, return_value_policy policy, handle parent,
const std::type_info *type_info, const std::type_info *type_info,
const std::type_info *type_info_backup,
void *(*copy_constructor)(const void *), void *(*copy_constructor)(const void *),
const void *existing_holder = nullptr) { const void *existing_holder = nullptr) {
void *src = const_cast<void *>(_src); void *src = const_cast<void *>(_src);
@ -153,6 +154,11 @@ public:
return handle((PyObject *) it_instance->second).inc_ref(); return handle((PyObject *) it_instance->second).inc_ref();
auto it = internals.registered_types_cpp.find(std::type_index(*type_info)); auto it = internals.registered_types_cpp.find(std::type_index(*type_info));
if (it == internals.registered_types_cpp.end()) {
type_info = type_info_backup;
it = internals.registered_types_cpp.find(std::type_index(*type_info));
}
if (it == internals.registered_types_cpp.end()) { if (it == internals.registered_types_cpp.end()) {
std::string tname = type_info->name(); std::string tname = type_info->name();
detail::clean_type_id(tname); detail::clean_type_id(tname);
@ -213,11 +219,11 @@ public:
static handle cast(const type &src, return_value_policy policy, handle parent) { static handle cast(const type &src, return_value_policy policy, handle parent) {
if (policy == return_value_policy::automatic) if (policy == return_value_policy::automatic)
policy = return_value_policy::copy; policy = return_value_policy::copy;
return type_caster_generic::cast(&src, policy, parent, &typeid(type), &copy_constructor); return cast(&src, policy, parent);
} }
static handle cast(const type *src, return_value_policy policy, handle parent) { static handle cast(const type *src, return_value_policy policy, handle parent) {
return type_caster_generic::cast(src, policy, parent, &typeid(type), &copy_constructor); return type_caster_generic::cast(src, policy, parent, src ? &typeid(*src) : nullptr, &typeid(type), &copy_constructor);
} }
template <typename T> using cast_op_type = pybind11::detail::cast_op_type<T>; template <typename T> using cast_op_type = pybind11::detail::cast_op_type<T>;
@ -664,7 +670,9 @@ public:
static handle cast(const holder_type &src, return_value_policy policy, handle parent) { static handle cast(const holder_type &src, return_value_policy policy, handle parent) {
return type_caster_generic::cast( return type_caster_generic::cast(
src.get(), policy, parent, &typeid(type), &copy_constructor, &src); src.get(), policy, parent,
src.get() ? &typeid(*src.get()) : nullptr, &typeid(type),
&copy_constructor, &src);
} }
protected: protected: