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Inline smart_holder_type_caster_support, trampoline_self_life_support in type_caster_base.h: the organization of the existing code makes it very difficult to factor the added code properly.

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Ralf W. Grosse-Kunstleve 2024-07-06 10:49:22 -07:00
parent 2180dd4b6b
commit 70ba91f721
7 changed files with 457 additions and 518 deletions
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2
CMakeLists.txt
View File

@ -154,8 +154,6 @@ set(PYBIND11_HEADERS
include/pybind11/detail/init.h
include/pybind11/detail/internals.h
include/pybind11/detail/smart_holder_poc.h
include/pybind11/detail/smart_holder_type_caster_support.h
include/pybind11/detail/smart_holder_value_and_holder_support.h
include/pybind11/detail/type_caster_base.h
include/pybind11/detail/typeid.h
include/pybind11/attr.h

1
include/pybind11/cast.h
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@ -12,7 +12,6 @@
#include "detail/common.h"
#include "detail/descr.h"
#include "detail/smart_holder_type_caster_support.h"
#include "detail/type_caster_base.h"
#include "detail/typeid.h"
#include "pytypes.h"

394
include/pybind11/detail/smart_holder_type_caster_support.h
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@ -1,394 +0,0 @@
#pragma once
// BAKEIN_WIP: IWYU cleanup
#include "../gil.h"
#include "../pytypes.h"
#include "../trampoline_self_life_support.h"
#include "common.h"
#include "dynamic_raw_ptr_cast_if_possible.h"
#include "internals.h"
#include "smart_holder_value_and_holder_support.h"
#include "typeid.h"
#include <cstdint>
#include <iterator>
#include <string>
#include <type_traits>
#include <typeinfo>
#include <utility>
PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
PYBIND11_NAMESPACE_BEGIN(detail)
PYBIND11_NAMESPACE_BEGIN(smart_holder_type_caster_support)
template <typename T, typename D>
handle smart_holder_from_unique_ptr(std::unique_ptr<T, D> &&src,
return_value_policy policy,
handle parent,
const std::pair<const void *, const type_info *> &st) {
if (policy != return_value_policy::automatic
&& policy != return_value_policy::automatic_reference
&& policy != return_value_policy::reference_internal
&& policy != return_value_policy::move) {
// SMART_HOLDER_WIP: IMPROVABLE: Error message.
throw cast_error("Invalid return_value_policy for unique_ptr.");
}
if (!src) {
return none().release();
}
void *src_raw_void_ptr = const_cast<void *>(st.first);
assert(st.second != nullptr);
const detail::type_info *tinfo = st.second;
if (handle existing_inst = find_registered_python_instance(src_raw_void_ptr, tinfo)) {
auto *self_life_support
= dynamic_raw_ptr_cast_if_possible<trampoline_self_life_support>(src.get());
if (self_life_support != nullptr) {
value_and_holder &v_h = self_life_support->v_h;
if (v_h.inst != nullptr && v_h.vh != nullptr) {
auto &holder = v_h.holder<pybindit::memory::smart_holder>();
if (!holder.is_disowned) {
pybind11_fail("smart_holder_from_unique_ptr: unexpected "
"smart_holder.is_disowned failure.");
}
// Critical transfer-of-ownership section. This must stay together.
self_life_support->deactivate_life_support();
holder.reclaim_disowned();
(void) src.release();
// Critical section end.
return existing_inst;
}
}
throw cast_error("Invalid unique_ptr: another instance owns this pointer already.");
}
auto inst = reinterpret_steal<object>(make_new_instance(tinfo->type));
auto *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;
if (static_cast<void *>(src.get()) == src_raw_void_ptr) {
// This is a multiple-inheritance situation that is incompatible with the current
// shared_from_this handling (see PR #3023).
// SMART_HOLDER_WIP: IMPROVABLE: Is there a better solution?
src_raw_void_ptr = nullptr;
}
auto smhldr
= pybindit::memory::smart_holder::from_unique_ptr(std::move(src), src_raw_void_ptr);
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 T, typename D>
handle smart_holder_from_unique_ptr(std::unique_ptr<T const, D> &&src,
return_value_policy policy,
handle parent,
const std::pair<const void *, const type_info *> &st) {
return smart_holder_from_unique_ptr(
std::unique_ptr<T, D>(const_cast<T *>(src.release()),
std::move(src.get_deleter())), // Const2Mutbl
policy,
parent,
st);
}
template <typename T>
handle smart_holder_from_shared_ptr(const std::shared_ptr<T> &src,
return_value_policy policy,
handle parent,
const std::pair<const void *, const type_info *> &st) {
switch (policy) {
case return_value_policy::automatic:
case return_value_policy::automatic_reference:
break;
case return_value_policy::take_ownership:
throw cast_error("Invalid return_value_policy for shared_ptr (take_ownership).");
case return_value_policy::copy:
case return_value_policy::move:
break;
case return_value_policy::reference:
throw cast_error("Invalid return_value_policy for shared_ptr (reference).");
case return_value_policy::reference_internal:
break;
}
if (!src) {
return none().release();
}
auto src_raw_ptr = src.get();
assert(st.second != nullptr);
void *src_raw_void_ptr = static_cast<void *>(src_raw_ptr);
const detail::type_info *tinfo = st.second;
if (handle existing_inst = find_registered_python_instance(src_raw_void_ptr, tinfo)) {
// SMART_HOLDER_WIP: MISSING: Enforcement of consistency with existing smart_holder.
// SMART_HOLDER_WIP: MISSING: keep_alive.
return existing_inst;
}
auto inst = reinterpret_steal<object>(make_new_instance(tinfo->type));
auto *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(
std::shared_ptr<void>(src, const_cast<void *>(st.first)));
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 T>
handle smart_holder_from_shared_ptr(const std::shared_ptr<T const> &src,
return_value_policy policy,
handle parent,
const std::pair<const void *, const type_info *> &st) {
return smart_holder_from_shared_ptr(std::const_pointer_cast<T>(src), // Const2Mutbl
policy,
parent,
st);
}
struct shared_ptr_parent_life_support {
PyObject *parent;
explicit shared_ptr_parent_life_support(PyObject *parent) : parent{parent} {
Py_INCREF(parent);
}
// NOLINTNEXTLINE(readability-make-member-function-const)
void operator()(void *) {
gil_scoped_acquire gil;
Py_DECREF(parent);
}
};
struct shared_ptr_trampoline_self_life_support {
PyObject *self;
explicit shared_ptr_trampoline_self_life_support(instance *inst)
: self{reinterpret_cast<PyObject *>(inst)} {
gil_scoped_acquire gil;
Py_INCREF(self);
}
// NOLINTNEXTLINE(readability-make-member-function-const)
void operator()(void *) {
gil_scoped_acquire gil;
Py_DECREF(self);
}
};
template <typename T,
typename D,
typename std::enable_if<std::is_default_constructible<D>::value, int>::type = 0>
inline std::unique_ptr<T, D> unique_with_deleter(T *raw_ptr, std::unique_ptr<D> &&deleter) {
if (deleter == nullptr) {
return std::unique_ptr<T, D>(raw_ptr);
}
return std::unique_ptr<T, D>(raw_ptr, std::move(*deleter));
}
template <typename T,
typename D,
typename std::enable_if<!std::is_default_constructible<D>::value, int>::type = 0>
inline std::unique_ptr<T, D> unique_with_deleter(T *raw_ptr, std::unique_ptr<D> &&deleter) {
if (deleter == nullptr) {
pybind11_fail("smart_holder_type_casters: deleter is not default constructible and no"
" instance available to return.");
}
return std::unique_ptr<T, D>(raw_ptr, std::move(*deleter));
}
template <typename T>
struct load_helper
: smart_holder_value_and_holder_support::value_and_holder_helper<value_and_holder> {
using holder_type = pybindit::memory::smart_holder;
value_and_holder loaded_v_h;
load_helper()
: smart_holder_value_and_holder_support::value_and_holder_helper<value_and_holder>(
&loaded_v_h) {}
T *loaded_as_raw_ptr_unowned() const {
void *void_ptr = nullptr;
if (have_holder()) {
throw_if_uninitialized_or_disowned_holder(typeid(T));
void_ptr = holder().template as_raw_ptr_unowned<void>();
} else if (loaded_v_h.vh != nullptr) {
void_ptr = loaded_v_h.value_ptr();
}
if (void_ptr == nullptr) {
return nullptr;
}
return convert_type(void_ptr);
}
T &loaded_as_lvalue_ref() const {
T *raw_ptr = loaded_as_raw_ptr_unowned();
if (raw_ptr == nullptr) {
throw reference_cast_error();
}
return *raw_ptr;
}
std::shared_ptr<T> make_shared_ptr_with_responsible_parent(handle parent) const {
return std::shared_ptr<T>(loaded_as_raw_ptr_unowned(),
shared_ptr_parent_life_support(parent.ptr()));
}
std::shared_ptr<T> loaded_as_shared_ptr(handle responsible_parent = nullptr) const {
if (!have_holder()) {
return nullptr;
}
throw_if_uninitialized_or_disowned_holder(typeid(T));
holder_type &hld = holder();
hld.ensure_is_not_disowned("loaded_as_shared_ptr");
if (hld.vptr_is_using_noop_deleter) {
if (responsible_parent) {
return make_shared_ptr_with_responsible_parent(responsible_parent);
}
throw std::runtime_error("Non-owning holder (loaded_as_shared_ptr).");
}
auto *void_raw_ptr = hld.template as_raw_ptr_unowned<void>();
auto *type_raw_ptr = convert_type(void_raw_ptr);
if (hld.pointee_depends_on_holder_owner) {
auto *vptr_gd_ptr = std::get_deleter<pybindit::memory::guarded_delete>(hld.vptr);
if (vptr_gd_ptr != nullptr) {
std::shared_ptr<void> released_ptr = vptr_gd_ptr->released_ptr.lock();
if (released_ptr) {
return std::shared_ptr<T>(released_ptr, type_raw_ptr);
}
std::shared_ptr<T> to_be_released(
type_raw_ptr, shared_ptr_trampoline_self_life_support(loaded_v_h.inst));
vptr_gd_ptr->released_ptr = to_be_released;
return to_be_released;
}
auto *sptsls_ptr = std::get_deleter<shared_ptr_trampoline_self_life_support>(hld.vptr);
if (sptsls_ptr != nullptr) {
// This code is reachable only if there are multiple registered_instances for the
// same pointee.
if (reinterpret_cast<PyObject *>(loaded_v_h.inst) == sptsls_ptr->self) {
pybind11_fail(
"ssmart_holder_type_caster_support loaded_as_shared_ptr failure: "
"loaded_v_h.inst == sptsls_ptr->self");
}
}
if (sptsls_ptr != nullptr
|| !pybindit::memory::type_has_shared_from_this(type_raw_ptr)) {
return std::shared_ptr<T>(
type_raw_ptr, shared_ptr_trampoline_self_life_support(loaded_v_h.inst));
}
if (hld.vptr_is_external_shared_ptr) {
pybind11_fail("smart_holder_type_casters loaded_as_shared_ptr failure: not "
"implemented: trampoline-self-life-support for external shared_ptr "
"to type inheriting from std::enable_shared_from_this.");
}
pybind11_fail("smart_holder_type_casters: loaded_as_shared_ptr failure: internal "
"inconsistency.");
}
std::shared_ptr<void> void_shd_ptr = hld.template as_shared_ptr<void>();
return std::shared_ptr<T>(void_shd_ptr, type_raw_ptr);
}
template <typename D>
std::unique_ptr<T, D> loaded_as_unique_ptr(const char *context = "loaded_as_unique_ptr") {
if (!have_holder()) {
return unique_with_deleter<T, D>(nullptr, std::unique_ptr<D>());
}
throw_if_uninitialized_or_disowned_holder(typeid(T));
throw_if_instance_is_currently_owned_by_shared_ptr();
holder().ensure_is_not_disowned(context);
holder().template ensure_compatible_rtti_uqp_del<T, D>(context);
holder().ensure_use_count_1(context);
auto raw_void_ptr = holder().template as_raw_ptr_unowned<void>();
void *value_void_ptr = loaded_v_h.value_ptr();
if (value_void_ptr != raw_void_ptr) {
pybind11_fail("smart_holder_type_casters: loaded_as_unique_ptr failure:"
" value_void_ptr != raw_void_ptr");
}
// SMART_HOLDER_WIP: MISSING: Safety checks for type conversions
// (T must be polymorphic or meet certain other conditions).
T *raw_type_ptr = convert_type(raw_void_ptr);
auto *self_life_support
= dynamic_raw_ptr_cast_if_possible<trampoline_self_life_support>(raw_type_ptr);
if (self_life_support == nullptr && holder().pointee_depends_on_holder_owner) {
throw value_error("Alias class (also known as trampoline) does not inherit from "
"py::trampoline_self_life_support, therefore the ownership of this "
"instance cannot safely be transferred to C++.");
}
// Temporary variable to store the extracted deleter in.
std::unique_ptr<D> extracted_deleter;
auto *gd = std::get_deleter<pybindit::memory::guarded_delete>(holder().vptr);
if (gd && gd->use_del_fun) { // Note the ensure_compatible_rtti_uqp_del<T, D>() call above.
// In smart_holder_poc, a custom deleter is always stored in a guarded delete.
// The guarded delete's std::function<void(void*)> actually points at the
// custom_deleter type, so we can verify it is of the custom deleter type and
// finally extract its deleter.
using custom_deleter_D = pybindit::memory::custom_deleter<T, D>;
const auto &custom_deleter_ptr = gd->del_fun.template target<custom_deleter_D>();
assert(custom_deleter_ptr != nullptr);
// Now that we have confirmed the type of the deleter matches the desired return
// value we can extract the function.
extracted_deleter = std::unique_ptr<D>(new D(std::move(custom_deleter_ptr->deleter)));
}
// Critical transfer-of-ownership section. This must stay together.
if (self_life_support != nullptr) {
holder().disown();
} else {
holder().release_ownership();
}
auto result = unique_with_deleter<T, D>(raw_type_ptr, std::move(extracted_deleter));
if (self_life_support != nullptr) {
self_life_support->activate_life_support(loaded_v_h);
} else {
loaded_v_h.value_ptr() = nullptr;
deregister_instance(loaded_v_h.inst, value_void_ptr, loaded_v_h.type);
}
// Critical section end.
return result;
}
#ifdef BAKEIN_WIP // Is this needed? shared_ptr_from_python(responsible_parent)
// This function will succeed even if the `responsible_parent` does not own the
// wrapped C++ object directly.
// It is the responsibility of the caller to ensure that the `responsible_parent`
// has a `keep_alive` relationship with the owner of the wrapped C++ object, or
// that the wrapped C++ object lives for the duration of the process.
static std::shared_ptr<T> shared_ptr_from_python(handle responsible_parent) {
smart_holder_type_caster_load<T> loader;
loader.load(responsible_parent, false);
return loader.loaded_as_shared_ptr(responsible_parent);
}
#endif
private:
T *convert_type(void *void_ptr) const {
#ifdef BAKEIN_WIP // Is this needed? implicit_casts
if (void_ptr != nullptr && load_impl.loaded_v_h_cpptype != nullptr
&& !load_impl.reinterpret_cast_deemed_ok && !load_impl.implicit_casts.empty()) {
for (auto implicit_cast : load_impl.implicit_casts) {
void_ptr = implicit_cast(void_ptr);
}
}
#endif
return static_cast<T *>(void_ptr);
}
};
PYBIND11_NAMESPACE_END(smart_holder_type_caster_support)
PYBIND11_NAMESPACE_END(detail)
PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)

59
include/pybind11/detail/smart_holder_value_and_holder_support.h
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@ -1,59 +0,0 @@
#pragma once
// BAKEIN_WIP: IWYU cleanup
#include "common.h"
#include "smart_holder_poc.h"
#include "typeid.h"
#include <memory>
#include <string>
#include <typeinfo>
PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
PYBIND11_NAMESPACE_BEGIN(detail)
PYBIND11_NAMESPACE_BEGIN(smart_holder_value_and_holder_support)
// BAKEIN_WIP: Factor out `struct value_and_holder` from type_caster_base.h,
// then this helper does not have to be templated.
template <typename VHType>
struct value_and_holder_helper {
const VHType *loaded_v_h;
explicit value_and_holder_helper(const VHType *loaded_v_h) : loaded_v_h{loaded_v_h} {}
bool have_holder() const {
return loaded_v_h->vh != nullptr && loaded_v_h->holder_constructed();
}
pybindit::memory::smart_holder &holder() const {
return loaded_v_h->template holder<pybindit::memory::smart_holder>();
}
void throw_if_uninitialized_or_disowned_holder(const char *typeid_name) const {
static const std::string missing_value_msg = "Missing value for wrapped C++ type `";
if (!holder().is_populated) {
throw value_error(missing_value_msg + clean_type_id(typeid_name)
+ "`: Python instance is uninitialized.");
}
if (!holder().has_pointee()) {
throw value_error(missing_value_msg + clean_type_id(typeid_name)
+ "`: Python instance was disowned.");
}
}
void throw_if_uninitialized_or_disowned_holder(const std::type_info &type_info) const {
throw_if_uninitialized_or_disowned_holder(type_info.name());
}
// have_holder() must be true or this function will fail.
void throw_if_instance_is_currently_owned_by_shared_ptr() const {
auto vptr_gd_ptr = std::get_deleter<pybindit::memory::guarded_delete>(holder().vptr);
if (vptr_gd_ptr != nullptr && !vptr_gd_ptr->released_ptr.expired()) {
throw value_error("Python instance is currently owned by a std::shared_ptr.");
}
}
};
PYBIND11_NAMESPACE_END(smart_holder_value_and_holder_support)
PYBIND11_NAMESPACE_END(detail)
PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)

460
include/pybind11/detail/type_caster_base.h
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@ -9,12 +9,13 @@
#pragma once
#include "../gil.h"
#include "../pytypes.h"
#include "common.h"
#include "descr.h"
#include "dynamic_raw_ptr_cast_if_possible.h"
#include "internals.h"
#include "smart_holder_poc.h"
#include "smart_holder_value_and_holder_support.h"
#include "typeid.h"
#include <cstdint>
@ -530,6 +531,455 @@ inline PyThreadState *get_thread_state_unchecked() {
void keep_alive_impl(handle nurse, handle patient);
inline PyObject *make_new_instance(PyTypeObject *type);
// SMART_HOLDER_WIP: Needs refactoring of existing pybind11 code.
inline bool deregister_instance(instance *self, void *valptr, const type_info *tinfo);
PYBIND11_NAMESPACE_END(detail)
// The original core idea for this struct goes back to PyCLIF:
// https://github.com/google/clif/blob/07f95d7e69dca2fcf7022978a55ef3acff506c19/clif/python/runtime.cc#L37
// URL provided here mainly to give proper credit. To fully explain the `HoldPyObj` feature, more
// context is needed (SMART_HOLDER_WIP).
struct trampoline_self_life_support {
detail::value_and_holder v_h;
trampoline_self_life_support() = default;
void activate_life_support(const detail::value_and_holder &v_h_) {
Py_INCREF((PyObject *) v_h_.inst);
v_h = v_h_;
}
void deactivate_life_support() {
Py_DECREF((PyObject *) v_h.inst);
v_h = detail::value_and_holder();
}
~trampoline_self_life_support() {
if (v_h.inst != nullptr && v_h.vh != nullptr) {
void *value_void_ptr = v_h.value_ptr();
if (value_void_ptr != nullptr) {
PyGILState_STATE threadstate = PyGILState_Ensure();
v_h.value_ptr() = nullptr;
v_h.holder<pybindit::memory::smart_holder>().release_disowned();
detail::deregister_instance(v_h.inst, value_void_ptr, v_h.type);
Py_DECREF((PyObject *) v_h.inst); // Must be after deregister.
PyGILState_Release(threadstate);
}
}
}
// For the next two, the default implementations generate undefined behavior (ASAN failures
// manually verified). The reason is that v_h needs to be kept default-initialized.
trampoline_self_life_support(const trampoline_self_life_support &) {}
trampoline_self_life_support(trampoline_self_life_support &&) noexcept {}
// These should never be needed (please provide test cases if you think they are).
trampoline_self_life_support &operator=(const trampoline_self_life_support &) = delete;
trampoline_self_life_support &operator=(trampoline_self_life_support &&) = delete;
};
PYBIND11_NAMESPACE_BEGIN(detail)
PYBIND11_NAMESPACE_BEGIN(smart_holder_type_caster_support)
struct value_and_holder_helper {
value_and_holder loaded_v_h;
bool have_holder() const {
return loaded_v_h.vh != nullptr && loaded_v_h.holder_constructed();
}
pybindit::memory::smart_holder &holder() const {
return loaded_v_h.holder<pybindit::memory::smart_holder>();
}
void throw_if_uninitialized_or_disowned_holder(const char *typeid_name) const {
static const std::string missing_value_msg = "Missing value for wrapped C++ type `";
if (!holder().is_populated) {
throw value_error(missing_value_msg + clean_type_id(typeid_name)
+ "`: Python instance is uninitialized.");
}
if (!holder().has_pointee()) {
throw value_error(missing_value_msg + clean_type_id(typeid_name)
+ "`: Python instance was disowned.");
}
}
void throw_if_uninitialized_or_disowned_holder(const std::type_info &type_info) const {
throw_if_uninitialized_or_disowned_holder(type_info.name());
}
// have_holder() must be true or this function will fail.
void throw_if_instance_is_currently_owned_by_shared_ptr() const {
auto vptr_gd_ptr = std::get_deleter<pybindit::memory::guarded_delete>(holder().vptr);
if (vptr_gd_ptr != nullptr && !vptr_gd_ptr->released_ptr.expired()) {
throw value_error("Python instance is currently owned by a std::shared_ptr.");
}
}
};
template <typename T, typename D>
handle smart_holder_from_unique_ptr(std::unique_ptr<T, D> &&src,
return_value_policy policy,
handle parent,
const std::pair<const void *, const type_info *> &st) {
if (policy != return_value_policy::automatic
&& policy != return_value_policy::automatic_reference
&& policy != return_value_policy::reference_internal
&& policy != return_value_policy::move) {
// SMART_HOLDER_WIP: IMPROVABLE: Error message.
throw cast_error("Invalid return_value_policy for unique_ptr.");
}
if (!src) {
return none().release();
}
void *src_raw_void_ptr = const_cast<void *>(st.first);
assert(st.second != nullptr);
const detail::type_info *tinfo = st.second;
if (handle existing_inst = find_registered_python_instance(src_raw_void_ptr, tinfo)) {
auto *self_life_support
= dynamic_raw_ptr_cast_if_possible<trampoline_self_life_support>(src.get());
if (self_life_support != nullptr) {
value_and_holder &v_h = self_life_support->v_h;
if (v_h.inst != nullptr && v_h.vh != nullptr) {
auto &holder = v_h.holder<pybindit::memory::smart_holder>();
if (!holder.is_disowned) {
pybind11_fail("smart_holder_from_unique_ptr: unexpected "
"smart_holder.is_disowned failure.");
}
// Critical transfer-of-ownership section. This must stay together.
self_life_support->deactivate_life_support();
holder.reclaim_disowned();
(void) src.release();
// Critical section end.
return existing_inst;
}
}
throw cast_error("Invalid unique_ptr: another instance owns this pointer already.");
}
auto inst = reinterpret_steal<object>(make_new_instance(tinfo->type));
auto *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;
if (static_cast<void *>(src.get()) == src_raw_void_ptr) {
// This is a multiple-inheritance situation that is incompatible with the current
// shared_from_this handling (see PR #3023).
// SMART_HOLDER_WIP: IMPROVABLE: Is there a better solution?
src_raw_void_ptr = nullptr;
}
auto smhldr
= pybindit::memory::smart_holder::from_unique_ptr(std::move(src), src_raw_void_ptr);
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 T, typename D>
handle smart_holder_from_unique_ptr(std::unique_ptr<T const, D> &&src,
return_value_policy policy,
handle parent,
const std::pair<const void *, const type_info *> &st) {
return smart_holder_from_unique_ptr(
std::unique_ptr<T, D>(const_cast<T *>(src.release()),
std::move(src.get_deleter())), // Const2Mutbl
policy,
parent,
st);
}
template <typename T>
handle smart_holder_from_shared_ptr(const std::shared_ptr<T> &src,
return_value_policy policy,
handle parent,
const std::pair<const void *, const type_info *> &st) {
switch (policy) {
case return_value_policy::automatic:
case return_value_policy::automatic_reference:
break;
case return_value_policy::take_ownership:
throw cast_error("Invalid return_value_policy for shared_ptr (take_ownership).");
case return_value_policy::copy:
case return_value_policy::move:
break;
case return_value_policy::reference:
throw cast_error("Invalid return_value_policy for shared_ptr (reference).");
case return_value_policy::reference_internal:
break;
}
if (!src) {
return none().release();
}
auto src_raw_ptr = src.get();
assert(st.second != nullptr);
void *src_raw_void_ptr = static_cast<void *>(src_raw_ptr);
const detail::type_info *tinfo = st.second;
if (handle existing_inst = find_registered_python_instance(src_raw_void_ptr, tinfo)) {
// SMART_HOLDER_WIP: MISSING: Enforcement of consistency with existing smart_holder.
// SMART_HOLDER_WIP: MISSING: keep_alive.
return existing_inst;
}
auto inst = reinterpret_steal<object>(make_new_instance(tinfo->type));
auto *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(
std::shared_ptr<void>(src, const_cast<void *>(st.first)));
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 T>
handle smart_holder_from_shared_ptr(const std::shared_ptr<T const> &src,
return_value_policy policy,
handle parent,
const std::pair<const void *, const type_info *> &st) {
return smart_holder_from_shared_ptr(std::const_pointer_cast<T>(src), // Const2Mutbl
policy,
parent,
st);
}
struct shared_ptr_parent_life_support {
PyObject *parent;
explicit shared_ptr_parent_life_support(PyObject *parent) : parent{parent} {
Py_INCREF(parent);
}
// NOLINTNEXTLINE(readability-make-member-function-const)
void operator()(void *) {
gil_scoped_acquire gil;
Py_DECREF(parent);
}
};
struct shared_ptr_trampoline_self_life_support {
PyObject *self;
explicit shared_ptr_trampoline_self_life_support(instance *inst)
: self{reinterpret_cast<PyObject *>(inst)} {
gil_scoped_acquire gil;
Py_INCREF(self);
}
// NOLINTNEXTLINE(readability-make-member-function-const)
void operator()(void *) {
gil_scoped_acquire gil;
Py_DECREF(self);
}
};
template <typename T,
typename D,
typename std::enable_if<std::is_default_constructible<D>::value, int>::type = 0>
inline std::unique_ptr<T, D> unique_with_deleter(T *raw_ptr, std::unique_ptr<D> &&deleter) {
if (deleter == nullptr) {
return std::unique_ptr<T, D>(raw_ptr);
}
return std::unique_ptr<T, D>(raw_ptr, std::move(*deleter));
}
template <typename T,
typename D,
typename std::enable_if<!std::is_default_constructible<D>::value, int>::type = 0>
inline std::unique_ptr<T, D> unique_with_deleter(T *raw_ptr, std::unique_ptr<D> &&deleter) {
if (deleter == nullptr) {
pybind11_fail("smart_holder_type_casters: deleter is not default constructible and no"
" instance available to return.");
}
return std::unique_ptr<T, D>(raw_ptr, std::move(*deleter));
}
template <typename T>
struct load_helper : value_and_holder_helper {
using holder_type = pybindit::memory::smart_holder;
T *loaded_as_raw_ptr_unowned() const {
void *void_ptr = nullptr;
if (have_holder()) {
throw_if_uninitialized_or_disowned_holder(typeid(T));
void_ptr = holder().template as_raw_ptr_unowned<void>();
} else if (loaded_v_h.vh != nullptr) {
void_ptr = loaded_v_h.value_ptr();
}
if (void_ptr == nullptr) {
return nullptr;
}
return convert_type(void_ptr);
}
T &loaded_as_lvalue_ref() const {
T *raw_ptr = loaded_as_raw_ptr_unowned();
if (raw_ptr == nullptr) {
throw reference_cast_error();
}
return *raw_ptr;
}
std::shared_ptr<T> make_shared_ptr_with_responsible_parent(handle parent) const {
return std::shared_ptr<T>(loaded_as_raw_ptr_unowned(),
shared_ptr_parent_life_support(parent.ptr()));
}
std::shared_ptr<T> loaded_as_shared_ptr(handle responsible_parent = nullptr) const {
if (!have_holder()) {
return nullptr;
}
throw_if_uninitialized_or_disowned_holder(typeid(T));
holder_type &hld = holder();
hld.ensure_is_not_disowned("loaded_as_shared_ptr");
if (hld.vptr_is_using_noop_deleter) {
if (responsible_parent) {
return make_shared_ptr_with_responsible_parent(responsible_parent);
}
throw std::runtime_error("Non-owning holder (loaded_as_shared_ptr).");
}
auto *void_raw_ptr = hld.template as_raw_ptr_unowned<void>();
auto *type_raw_ptr = convert_type(void_raw_ptr);
if (hld.pointee_depends_on_holder_owner) {
auto *vptr_gd_ptr = std::get_deleter<pybindit::memory::guarded_delete>(hld.vptr);
if (vptr_gd_ptr != nullptr) {
std::shared_ptr<void> released_ptr = vptr_gd_ptr->released_ptr.lock();
if (released_ptr) {
return std::shared_ptr<T>(released_ptr, type_raw_ptr);
}
std::shared_ptr<T> to_be_released(
type_raw_ptr, shared_ptr_trampoline_self_life_support(loaded_v_h.inst));
vptr_gd_ptr->released_ptr = to_be_released;
return to_be_released;
}
auto *sptsls_ptr = std::get_deleter<shared_ptr_trampoline_self_life_support>(hld.vptr);
if (sptsls_ptr != nullptr) {
// This code is reachable only if there are multiple registered_instances for the
// same pointee.
if (reinterpret_cast<PyObject *>(loaded_v_h.inst) == sptsls_ptr->self) {
pybind11_fail("smart_holder_type_caster_support loaded_as_shared_ptr failure: "
"loaded_v_h.inst == sptsls_ptr->self");
}
}
if (sptsls_ptr != nullptr
|| !pybindit::memory::type_has_shared_from_this(type_raw_ptr)) {
return std::shared_ptr<T>(
type_raw_ptr, shared_ptr_trampoline_self_life_support(loaded_v_h.inst));
}
if (hld.vptr_is_external_shared_ptr) {
pybind11_fail("smart_holder_type_casters loaded_as_shared_ptr failure: not "
"implemented: trampoline-self-life-support for external shared_ptr "
"to type inheriting from std::enable_shared_from_this.");
}
pybind11_fail("smart_holder_type_casters: loaded_as_shared_ptr failure: internal "
"inconsistency.");
}
std::shared_ptr<void> void_shd_ptr = hld.template as_shared_ptr<void>();
return std::shared_ptr<T>(void_shd_ptr, type_raw_ptr);
}
template <typename D>
std::unique_ptr<T, D> loaded_as_unique_ptr(const char *context = "loaded_as_unique_ptr") {
if (!have_holder()) {
return unique_with_deleter<T, D>(nullptr, std::unique_ptr<D>());
}
throw_if_uninitialized_or_disowned_holder(typeid(T));
throw_if_instance_is_currently_owned_by_shared_ptr();
holder().ensure_is_not_disowned(context);
holder().template ensure_compatible_rtti_uqp_del<T, D>(context);
holder().ensure_use_count_1(context);
auto raw_void_ptr = holder().template as_raw_ptr_unowned<void>();
void *value_void_ptr = loaded_v_h.value_ptr();
if (value_void_ptr != raw_void_ptr) {
pybind11_fail("smart_holder_type_casters: loaded_as_unique_ptr failure:"
" value_void_ptr != raw_void_ptr");
}
// SMART_HOLDER_WIP: MISSING: Safety checks for type conversions
// (T must be polymorphic or meet certain other conditions).
T *raw_type_ptr = convert_type(raw_void_ptr);
auto *self_life_support
= dynamic_raw_ptr_cast_if_possible<trampoline_self_life_support>(raw_type_ptr);
if (self_life_support == nullptr && holder().pointee_depends_on_holder_owner) {
throw value_error("Alias class (also known as trampoline) does not inherit from "
"py::trampoline_self_life_support, therefore the ownership of this "
"instance cannot safely be transferred to C++.");
}
// Temporary variable to store the extracted deleter in.
std::unique_ptr<D> extracted_deleter;
auto *gd = std::get_deleter<pybindit::memory::guarded_delete>(holder().vptr);
if (gd && gd->use_del_fun) { // Note the ensure_compatible_rtti_uqp_del<T, D>() call above.
// In smart_holder_poc, a custom deleter is always stored in a guarded delete.
// The guarded delete's std::function<void(void*)> actually points at the
// custom_deleter type, so we can verify it is of the custom deleter type and
// finally extract its deleter.
using custom_deleter_D = pybindit::memory::custom_deleter<T, D>;
const auto &custom_deleter_ptr = gd->del_fun.template target<custom_deleter_D>();
assert(custom_deleter_ptr != nullptr);
// Now that we have confirmed the type of the deleter matches the desired return
// value we can extract the function.
extracted_deleter = std::unique_ptr<D>(new D(std::move(custom_deleter_ptr->deleter)));
}
// Critical transfer-of-ownership section. This must stay together.
if (self_life_support != nullptr) {
holder().disown();
} else {
holder().release_ownership();
}
auto result = unique_with_deleter<T, D>(raw_type_ptr, std::move(extracted_deleter));
if (self_life_support != nullptr) {
self_life_support->activate_life_support(loaded_v_h);
} else {
loaded_v_h.value_ptr() = nullptr;
deregister_instance(loaded_v_h.inst, value_void_ptr, loaded_v_h.type);
}
// Critical section end.
return result;
}
#ifdef BAKEIN_WIP // Is this needed? shared_ptr_from_python(responsible_parent)
// This function will succeed even if the `responsible_parent` does not own the
// wrapped C++ object directly.
// It is the responsibility of the caller to ensure that the `responsible_parent`
// has a `keep_alive` relationship with the owner of the wrapped C++ object, or
// that the wrapped C++ object lives for the duration of the process.
static std::shared_ptr<T> shared_ptr_from_python(handle responsible_parent) {
smart_holder_type_caster_load<T> loader;
loader.load(responsible_parent, false);
return loader.loaded_as_shared_ptr(responsible_parent);
}
#endif
private:
T *convert_type(void *void_ptr) const {
#ifdef BAKEIN_WIP // Is this needed? implicit_casts
if (void_ptr != nullptr && load_impl.loaded_v_h_cpptype != nullptr
&& !load_impl.reinterpret_cast_deemed_ok && !load_impl.implicit_casts.empty()) {
for (auto implicit_cast : load_impl.implicit_casts) {
void_ptr = implicit_cast(void_ptr);
}
}
#endif
return static_cast<T *>(void_ptr);
}
};
PYBIND11_NAMESPACE_END(smart_holder_type_caster_support)
class type_caster_generic {
public:
PYBIND11_NOINLINE explicit type_caster_generic(const std::type_info &type_info)
@ -635,10 +1085,10 @@ public:
// Base methods for generic caster; there are overridden in copyable_holder_caster
void load_value(value_and_holder &&v_h) {
if (typeinfo->default_holder) {
smart_holder_value_and_holder_support::value_and_holder_helper<value_and_holder>
vh_helper(&v_h);
if (vh_helper.have_holder()) {
vh_helper.throw_if_uninitialized_or_disowned_holder(typeid(cpptype));
smart_holder_type_caster_support::value_and_holder_helper v_h_helper;
v_h_helper.loaded_v_h = v_h;
if (v_h_helper.have_holder()) {
v_h_helper.throw_if_uninitialized_or_disowned_holder(typeid(cpptype));
}
}
auto *&vptr = v_h.value_ptr();

57
include/pybind11/trampoline_self_life_support.h
View File

@ -1,61 +1,8 @@
// Copyright (c) 2021 The Pybind Development Team.
// Copyright (c) 2024 The Pybind Development Team.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#pragma once
#include "detail/common.h"
#include "detail/smart_holder_poc.h"
// BAKEIN_WIP: Needs refactoring of existing pybind11 code.
#include "detail/type_caster_base.h"
PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
PYBIND11_NAMESPACE_BEGIN(detail)
// SMART_HOLDER_WIP: Needs refactoring of existing pybind11 code.
inline bool deregister_instance(instance *self, void *valptr, const type_info *tinfo);
PYBIND11_NAMESPACE_END(detail)
// The original core idea for this struct goes back to PyCLIF:
// https://github.com/google/clif/blob/07f95d7e69dca2fcf7022978a55ef3acff506c19/clif/python/runtime.cc#L37
// URL provided here mainly to give proper credit. To fully explain the `HoldPyObj` feature, more
// context is needed (SMART_HOLDER_WIP).
struct trampoline_self_life_support {
detail::value_and_holder v_h;
trampoline_self_life_support() = default;
void activate_life_support(const detail::value_and_holder &v_h_) {
Py_INCREF((PyObject *) v_h_.inst);
v_h = v_h_;
}
void deactivate_life_support() {
Py_DECREF((PyObject *) v_h.inst);
v_h = detail::value_and_holder();
}
~trampoline_self_life_support() {
if (v_h.inst != nullptr && v_h.vh != nullptr) {
void *value_void_ptr = v_h.value_ptr();
if (value_void_ptr != nullptr) {
PyGILState_STATE threadstate = PyGILState_Ensure();
v_h.value_ptr() = nullptr;
v_h.holder<pybindit::memory::smart_holder>().release_disowned();
detail::deregister_instance(v_h.inst, value_void_ptr, v_h.type);
Py_DECREF((PyObject *) v_h.inst); // Must be after deregister.
PyGILState_Release(threadstate);
}
}
}
// For the next two, the default implementations generate undefined behavior (ASAN failures
// manually verified). The reason is that v_h needs to be kept default-initialized.
trampoline_self_life_support(const trampoline_self_life_support &) {}
trampoline_self_life_support(trampoline_self_life_support &&) noexcept {}
// These should never be needed (please provide test cases if you think they are).
trampoline_self_life_support &operator=(const trampoline_self_life_support &) = delete;
trampoline_self_life_support &operator=(trampoline_self_life_support &&) = delete;
};
PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)

2
tests/extra_python_package/test_files.py
View File

@ -60,8 +60,6 @@ detail_headers = {
"include/pybind11/detail/init.h",
"include/pybind11/detail/internals.h",
"include/pybind11/detail/smart_holder_poc.h",
"include/pybind11/detail/smart_holder_type_caster_support.h",
"include/pybind11/detail/smart_holder_value_and_holder_support.h",
"include/pybind11/detail/type_caster_base.h",
"include/pybind11/detail/typeid.h",
}