Copying classh type_casters from test_classh_wip.cpp UNMODIFIED, as a baseline for generalizing the code.

This commit is contained in:
Ralf W. Grosse-Kunstleve 2021-01-17 12:11:59 -08:00
parent 2a7d41c193
commit 29414e6e95

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@ -0,0 +1,367 @@
namespace pybind11 {
namespace detail {
using namespace pybind11_tests::classh_wip;
inline std::pair<bool, handle> find_existing_python_instance(void *src_void_ptr,
const detail::type_info *tinfo) {
// Loop copied from type_caster_generic::cast.
// IMPROVEABLE: Factor out of type_caster_generic::cast.
auto it_instances = get_internals().registered_instances.equal_range(src_void_ptr);
for (auto it_i = it_instances.first; it_i != it_instances.second; ++it_i) {
for (auto instance_type : detail::all_type_info(Py_TYPE(it_i->second))) {
if (instance_type && same_type(*instance_type->cpptype, *tinfo->cpptype))
return std::make_pair(true, handle((PyObject *) it_i->second).inc_ref());
}
}
return std::make_pair(false, handle());
}
template <typename T>
struct smart_holder_type_caster_load {
using holder_type = pybindit::memory::smart_holder;
bool load(handle src, bool /*convert*/) {
if (!isinstance<T>(src))
return false;
auto inst = reinterpret_cast<instance *>(src.ptr());
loaded_v_h = inst->get_value_and_holder(get_type_info(typeid(T)));
if (!loaded_v_h.holder_constructed()) {
// IMPROVEABLE: Error message. A change to the existing internals is
// needed to cleanly distinguish between uninitialized or disowned.
throw std::runtime_error("Missing value for wrapped C++ type:"
" Python instance is uninitialized or was disowned.");
}
loaded_smhldr_ptr = &loaded_v_h.holder<holder_type>();
return true;
}
std::unique_ptr<T> loaded_as_unique_ptr() {
void *value_void_ptr = loaded_v_h.value_ptr();
auto unq_ptr = loaded_smhldr_ptr->as_unique_ptr<mpty>();
loaded_v_h.holder<holder_type>().~holder_type();
loaded_v_h.set_holder_constructed(false);
loaded_v_h.value_ptr() = nullptr;
deregister_instance(loaded_v_h.inst, value_void_ptr, loaded_v_h.type);
return unq_ptr;
}
protected:
value_and_holder loaded_v_h;
holder_type *loaded_smhldr_ptr = nullptr;
};
// type_caster_base BEGIN
// clang-format off
// Helper factored out of type_caster_base.
struct make_constructor {
using Constructor = void *(*)(const void *);
/* Only enabled when the types are {copy,move}-constructible *and* when the type
does not have a private operator new implementation. */
template <typename T, typename = enable_if_t<is_copy_constructible<T>::value>>
static auto make_copy_constructor(const T *x) -> decltype(new T(*x), Constructor{}) {
return [](const void *arg) -> void * {
return new T(*reinterpret_cast<const T *>(arg));
};
}
template <typename T, typename = enable_if_t<std::is_move_constructible<T>::value>>
static auto make_move_constructor(const T *x) -> decltype(new T(std::move(*const_cast<T *>(x))), Constructor{}) {
return [](const void *arg) -> void * {
return new T(std::move(*const_cast<T *>(reinterpret_cast<const T *>(arg))));
};
}
static Constructor make_copy_constructor(...) { return nullptr; }
static Constructor make_move_constructor(...) { return nullptr; }
};
// clang-format on
// type_caster_base END
template <>
struct type_caster<mpty> : smart_holder_type_caster_load<mpty> {
static constexpr auto name = _<mpty>();
// static handle cast(mpty, ...)
// is redundant (leads to ambiguous overloads).
static handle cast(mpty &&src, return_value_policy /*policy*/, handle parent) {
// type_caster_base BEGIN
// clang-format off
return cast(&src, return_value_policy::move, parent);
// clang-format on
// type_caster_base END
}
static handle cast(mpty const &src, return_value_policy policy, handle parent) {
// type_caster_base BEGIN
// clang-format off
if (policy == return_value_policy::automatic || policy == return_value_policy::automatic_reference)
policy = return_value_policy::copy;
return cast(&src, policy, parent);
// clang-format on
// type_caster_base END
}
static handle cast(mpty &src, return_value_policy policy, handle parent) {
return cast(const_cast<mpty const &>(src), policy, parent); // Mutbl2Const
}
static handle cast(mpty const *src, return_value_policy policy, handle parent) {
auto st = type_caster_base<mpty>::src_and_type(src);
return cast_const_raw_ptr( // Originally type_caster_generic::cast.
st.first,
policy,
parent,
st.second,
make_constructor::make_copy_constructor(src),
make_constructor::make_move_constructor(src));
}
static handle cast(mpty *src, return_value_policy policy, handle parent) {
return cast(const_cast<mpty const *>(src), policy, parent); // Mutbl2Const
}
template <typename T_>
using cast_op_type = conditional_t<
std::is_same<remove_reference_t<T_>, mpty const *>::value,
mpty const *,
conditional_t<
std::is_same<remove_reference_t<T_>, mpty *>::value,
mpty *,
conditional_t<
std::is_same<T_, mpty const &>::value,
mpty const &,
conditional_t<std::is_same<T_, mpty &>::value,
mpty &,
conditional_t<std::is_same<T_, mpty &&>::value, mpty &&, mpty>>>>>;
// clang-format off
operator mpty() { return loaded_smhldr_ptr->lvalue_ref<mpty>(); }
operator mpty&&() && { return loaded_smhldr_ptr->rvalue_ref<mpty>(); }
operator mpty const&() { return loaded_smhldr_ptr->lvalue_ref<mpty>(); }
operator mpty&() { return loaded_smhldr_ptr->lvalue_ref<mpty>(); }
operator mpty const*() { return loaded_smhldr_ptr->as_raw_ptr_unowned<mpty>(); }
operator mpty*() { return loaded_smhldr_ptr->as_raw_ptr_unowned<mpty>(); }
// clang-format on
// Originally type_caster_generic::cast.
PYBIND11_NOINLINE static handle cast_const_raw_ptr(const void *_src,
return_value_policy policy,
handle parent,
const detail::type_info *tinfo,
void *(*copy_constructor)(const void *),
void *(*move_constructor)(const void *),
const void *existing_holder = nullptr) {
if (!tinfo) // no type info: error will be set already
return handle();
void *src = const_cast<void *>(_src);
if (src == nullptr)
return none().release();
auto existing_inst = find_existing_python_instance(src, tinfo);
if (existing_inst.first)
return existing_inst.second;
auto inst = reinterpret_steal<object>(make_new_instance(tinfo->type));
auto wrapper = reinterpret_cast<instance *>(inst.ptr());
wrapper->owned = false;
void *&valueptr = values_and_holders(wrapper).begin()->value_ptr();
switch (policy) {
case return_value_policy::automatic:
case return_value_policy::take_ownership:
valueptr = src;
wrapper->owned = true;
break;
case return_value_policy::automatic_reference:
case return_value_policy::reference:
valueptr = src;
wrapper->owned = false;
break;
case return_value_policy::copy:
if (copy_constructor)
valueptr = copy_constructor(src);
else {
#if defined(NDEBUG)
throw cast_error("return_value_policy = copy, but type is "
"non-copyable! (compile in debug mode for details)");
#else
std::string type_name(tinfo->cpptype->name());
detail::clean_type_id(type_name);
throw cast_error("return_value_policy = copy, but type " + type_name
+ " is non-copyable!");
#endif
}
wrapper->owned = true;
break;
case return_value_policy::move:
if (move_constructor)
valueptr = move_constructor(src);
else if (copy_constructor)
valueptr = copy_constructor(src);
else {
#if defined(NDEBUG)
throw cast_error("return_value_policy = move, but type is neither "
"movable nor copyable! "
"(compile in debug mode for details)");
#else
std::string type_name(tinfo->cpptype->name());
detail::clean_type_id(type_name);
throw cast_error("return_value_policy = move, but type " + type_name
+ " is neither movable nor copyable!");
#endif
}
wrapper->owned = true;
break;
case return_value_policy::reference_internal:
valueptr = src;
wrapper->owned = false;
keep_alive_impl(inst, parent);
break;
default:
throw cast_error("unhandled return_value_policy: should not happen!");
}
tinfo->init_instance(wrapper, existing_holder);
return inst.release();
}
};
template <>
struct type_caster<std::shared_ptr<mpty>> : smart_holder_type_caster_load<mpty> {
static constexpr auto name = _<std::shared_ptr<mpty>>();
static handle
cast(const std::shared_ptr<mpty> &src, return_value_policy policy, handle parent) {
if (policy != return_value_policy::automatic
&& policy != return_value_policy::reference_internal) {
// IMPROVEABLE: Error message.
throw cast_error("Invalid return_value_policy for shared_ptr.");
}
auto src_raw_ptr = src.get();
auto st = type_caster_base<mpty>::src_and_type(src_raw_ptr);
if (st.first == nullptr)
return none().release(); // PyErr was set already.
void *src_raw_void_ptr = static_cast<void *>(src_raw_ptr);
const detail::type_info *tinfo = st.second;
auto existing_inst = find_existing_python_instance(src_raw_void_ptr, tinfo);
if (existing_inst.first)
// MISSING: Enforcement of consistency with existing smart_holder.
// MISSING: keep_alive.
return existing_inst.second;
object inst = reinterpret_steal<object>(make_new_instance(tinfo->type));
instance *inst_raw_ptr = reinterpret_cast<instance *>(inst.ptr());
inst_raw_ptr->owned = true;
void *&valueptr = values_and_holders(inst_raw_ptr).begin()->value_ptr();
valueptr = src_raw_void_ptr;
auto smhldr = pybindit::memory::smart_holder::from_shared_ptr(src);
tinfo->init_instance(inst_raw_ptr, static_cast<const void *>(&smhldr));
if (policy == return_value_policy::reference_internal)
keep_alive_impl(inst, parent);
return inst.release();
}
template <typename>
using cast_op_type = std::shared_ptr<mpty>;
operator std::shared_ptr<mpty>() { return loaded_smhldr_ptr->as_shared_ptr<mpty>(); }
};
template <>
struct type_caster<std::shared_ptr<mpty const>> : smart_holder_type_caster_load<mpty> {
static constexpr auto name = _<std::shared_ptr<mpty const>>();
static handle
cast(const std::shared_ptr<mpty const> &src, return_value_policy policy, handle parent) {
return type_caster<std::shared_ptr<mpty>>::cast(
std::const_pointer_cast<mpty>(src), // Const2Mutbl
policy,
parent);
}
template <typename>
using cast_op_type = std::shared_ptr<mpty const>;
operator std::shared_ptr<mpty const>() { return loaded_smhldr_ptr->as_shared_ptr<mpty>(); }
};
template <>
struct type_caster<std::unique_ptr<mpty>> : smart_holder_type_caster_load<mpty> {
static constexpr auto name = _<std::unique_ptr<mpty>>();
static handle cast(std::unique_ptr<mpty> &&src, return_value_policy policy, handle parent) {
if (policy != return_value_policy::automatic
&& policy != return_value_policy::reference_internal) {
// IMPROVEABLE: Error message.
throw cast_error("Invalid return_value_policy for unique_ptr.");
}
auto src_raw_ptr = src.get();
auto st = type_caster_base<mpty>::src_and_type(src_raw_ptr);
if (st.first == nullptr)
return none().release(); // PyErr was set already.
void *src_raw_void_ptr = static_cast<void *>(src_raw_ptr);
const detail::type_info *tinfo = st.second;
auto existing_inst = find_existing_python_instance(src_raw_void_ptr, tinfo);
if (existing_inst.first)
throw cast_error("Invalid unique_ptr: another instance owns this pointer already.");
object inst = reinterpret_steal<object>(make_new_instance(tinfo->type));
instance *inst_raw_ptr = reinterpret_cast<instance *>(inst.ptr());
inst_raw_ptr->owned = true;
void *&valueptr = values_and_holders(inst_raw_ptr).begin()->value_ptr();
valueptr = src_raw_void_ptr;
auto smhldr = pybindit::memory::smart_holder::from_unique_ptr(std::move(src));
tinfo->init_instance(inst_raw_ptr, static_cast<const void *>(&smhldr));
if (policy == return_value_policy::reference_internal)
keep_alive_impl(inst, parent);
return inst.release();
}
template <typename>
using cast_op_type = std::unique_ptr<mpty>;
operator std::unique_ptr<mpty>() { return loaded_as_unique_ptr(); }
};
template <>
struct type_caster<std::unique_ptr<mpty const>> : smart_holder_type_caster_load<mpty> {
static constexpr auto name = _<std::unique_ptr<mpty const>>();
static handle
cast(std::unique_ptr<mpty const> &&src, return_value_policy policy, handle parent) {
return type_caster<std::unique_ptr<mpty>>::cast(
std::unique_ptr<mpty>(const_cast<mpty *>(src.release())), // Const2Mutbl
policy,
parent);
}
template <typename>
using cast_op_type = std::unique_ptr<mpty const>;
operator std::unique_ptr<mpty const>() { return loaded_as_unique_ptr(); }
};
} // namespace detail
} // namespace pybind11