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Commit 63abf872 by Ralf W. Grosse-Kunstleve
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Removing detail/smart_holder_type_casters.h in separate commit.

parent c8eb29c8
Showing with 0 additions and 649 deletions
include/pybind11/detail/smart_holder_type_casters.h deleted 100644 → 0
// Copyright (c) 2020-2021 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 "../cast.h"
#include "../pytypes.h"
#include "class.h"
#include "common.h"
#include "descr.h"
#include "internals.h"
#include "smart_holder_poc.h"
#include <memory>
#include <stdexcept>
#include <string>
#include <type_traits>
#include <utility>
namespace pybind11 {
using pybindit::memory::smart_holder;
namespace detail {
// The modified_type_caster_generic_load_impl could replace type_caster_generic::load_impl but not
// vice versa. The main difference is that the original code only propagates a reference to the
// held value, while the modified implementation propagates value_and_holder.
// clang-format off
class modified_type_caster_generic_load_impl {
public:
PYBIND11_NOINLINE modified_type_caster_generic_load_impl(const std::type_info &type_info)
: typeinfo(get_type_info(type_info)), cpptype(&type_info) { }
explicit modified_type_caster_generic_load_impl(const type_info *typeinfo = nullptr)
: typeinfo(typeinfo), cpptype(typeinfo ? typeinfo->cpptype : nullptr) { }
bool load(handle src, bool convert) {
return load_impl<modified_type_caster_generic_load_impl>(src, convert);
}
// Base methods for generic caster; there are overridden in copyable_holder_caster
void load_value_and_holder(value_and_holder &&v_h) {
loaded_v_h = std::move(v_h);
if (!loaded_v_h.holder_constructed()) {
// IMPROVABLE: 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.");
}
if (v_h.value_ptr() == nullptr) {
pybind11_fail("smart_holder_type_casters: Unexpected v_h.value_ptr() nullptr.");
}
loaded_v_h.type = typeinfo;
}
bool try_implicit_casts(handle src, bool convert) {
for (auto &cast : typeinfo->implicit_casts) {
modified_type_caster_generic_load_impl sub_caster(*cast.first);
if (sub_caster.load(src, convert)) {
if (loaded_v_h_cpptype != nullptr) {
pybind11_fail("smart_holder_type_casters: try_implicit_casts failure.");
}
loaded_v_h = sub_caster.loaded_v_h;
loaded_v_h_cpptype = cast.first;
implicit_cast = cast.second;
return true;
}
}
return false;
}
bool try_direct_conversions(handle src) {
for (auto &converter : *typeinfo->direct_conversions) {
if (converter(src.ptr(), loaded_v_h.value_ptr()))
return true;
}
return false;
}
PYBIND11_NOINLINE static void *local_load(PyObject *src, const type_info *ti) {
std::unique_ptr<modified_type_caster_generic_load_impl> loader(
new modified_type_caster_generic_load_impl(ti));
if (loader->load(src, false)) {
// Trick to work with the existing pybind11 internals.
// The void pointer is immediately captured in a new unique_ptr in
// try_load_foreign_module_local. If this assumption is violated sanitizers
// will most likely flag a leak (verified to be the case with ASAN).
return static_cast<void *>(loader.release());
}
return nullptr;
}
/// Try to load with foreign typeinfo, if available. Used when there is no
/// native typeinfo, or when the native one wasn't able to produce a value.
PYBIND11_NOINLINE bool try_load_foreign_module_local(handle src) {
constexpr auto *local_key = PYBIND11_MODULE_LOCAL_ID;
const auto pytype = type::handle_of(src);
if (!hasattr(pytype, local_key))
return false;
type_info *foreign_typeinfo = reinterpret_borrow<capsule>(getattr(pytype, local_key));
// Only consider this foreign loader if actually foreign and is a loader of the correct cpp type
if (foreign_typeinfo->module_local_load == &local_load
|| (cpptype && !same_type(*cpptype, *foreign_typeinfo->cpptype)))
return false;
void* foreign_loader_void_ptr =
foreign_typeinfo->module_local_load(src.ptr(), foreign_typeinfo);
if (foreign_loader_void_ptr != nullptr) {
auto foreign_loader = std::unique_ptr<modified_type_caster_generic_load_impl>(
static_cast<modified_type_caster_generic_load_impl *>(foreign_loader_void_ptr));
// Magic number intentionally hard-coded for simplicity and maximum robustness.
if (foreign_loader->local_load_safety_guard != 1887406645) {
pybind11_fail(
"smart_holder_type_casters: Unexpected local_load_safety_guard,"
" possibly due to py::class_ holder mixup.");
}
if (loaded_v_h_cpptype != nullptr) {
pybind11_fail("smart_holder_type_casters: try_load_foreign_module_local failure.");
}
loaded_v_h = foreign_loader->loaded_v_h;
loaded_v_h_cpptype = foreign_loader->loaded_v_h_cpptype;
implicit_cast = foreign_loader->implicit_cast;
return true;
}
return false;
}
// Implementation of `load`; this takes the type of `this` so that it can dispatch the relevant
// bits of code between here and copyable_holder_caster where the two classes need different
// logic (without having to resort to virtual inheritance).
template <typename ThisT>
PYBIND11_NOINLINE bool load_impl(handle src, bool convert) {
if (!src) return false;
if (!typeinfo) return try_load_foreign_module_local(src);
if (src.is_none()) {
// Defer accepting None to other overloads (if we aren't in convert mode):
if (!convert) return false;
loaded_v_h = value_and_holder();
return true;
}
auto &this_ = static_cast<ThisT &>(*this);
PyTypeObject *srctype = Py_TYPE(src.ptr());
// Case 1: If src is an exact type match for the target type then we can reinterpret_cast
// the instance's value pointer to the target type:
if (srctype == typeinfo->type) {
this_.load_value_and_holder(reinterpret_cast<instance *>(src.ptr())->get_value_and_holder());
return true;
}
// Case 2: We have a derived class
else if (PyType_IsSubtype(srctype, typeinfo->type)) {
auto &bases = all_type_info(srctype); // subtype bases
bool no_cpp_mi = typeinfo->simple_type;
// Case 2a: the python type is a Python-inherited derived class that inherits from just
// one simple (no MI) pybind11 class, or is an exact match, so the C++ instance is of
// the right type and we can use reinterpret_cast.
// (This is essentially the same as case 2b, but because not using multiple inheritance
// is extremely common, we handle it specially to avoid the loop iterator and type
// pointer lookup overhead)
if (bases.size() == 1 && (no_cpp_mi || bases.front()->type == typeinfo->type)) {
this_.load_value_and_holder(reinterpret_cast<instance *>(src.ptr())->get_value_and_holder());
loaded_v_h_cpptype = bases.front()->cpptype;
reinterpret_cast_deemed_ok = true;
return true;
}
// Case 2b: the python type inherits from multiple C++ bases. Check the bases to see if
// we can find an exact match (or, for a simple C++ type, an inherited match); if so, we
// can safely reinterpret_cast to the relevant pointer.
else if (bases.size() > 1) {
for (auto base : bases) {
if (no_cpp_mi ? PyType_IsSubtype(base->type, typeinfo->type) : base->type == typeinfo->type) {
this_.load_value_and_holder(reinterpret_cast<instance *>(src.ptr())->get_value_and_holder(base));
loaded_v_h_cpptype = base->cpptype;
reinterpret_cast_deemed_ok = true;
return true;
}
}
}
// Case 2c: C++ multiple inheritance is involved and we couldn't find an exact type match
// in the registered bases, above, so try implicit casting (needed for proper C++ casting
// when MI is involved).
if (this_.try_implicit_casts(src, convert)) {
return true;
}
}
// Perform an implicit conversion
if (convert) {
for (auto &converter : typeinfo->implicit_conversions) {
auto temp = reinterpret_steal<object>(converter(src.ptr(), typeinfo->type));
if (load_impl<ThisT>(temp, false)) {
loader_life_support::add_patient(temp);
return true;
}
}
if (this_.try_direct_conversions(src))
return true;
}
// Failed to match local typeinfo. Try again with global.
if (typeinfo->module_local) {
if (auto gtype = get_global_type_info(*typeinfo->cpptype)) {
typeinfo = gtype;
return load(src, false);
}
}
// Global typeinfo has precedence over foreign module_local
return try_load_foreign_module_local(src);
}
const type_info *typeinfo = nullptr;
const std::type_info *cpptype = nullptr;
const std::type_info *loaded_v_h_cpptype = nullptr;
void *(*implicit_cast)(void *) = nullptr;
value_and_holder loaded_v_h;
bool reinterpret_cast_deemed_ok = false;
// Magic number intentionally hard-coded, to guard against class_ holder mixups.
// Ideally type_caster_generic would have a similar guard, but this requires a change there.
std::size_t local_load_safety_guard = 1887406645; // 32-bit compatible value for portability.
};
// clang-format on
struct smart_holder_type_caster_class_hooks {
using is_smart_holder_type_caster = std::true_type;
static decltype(&modified_type_caster_generic_load_impl::local_load)
get_local_load_function_ptr() {
return &modified_type_caster_generic_load_impl::local_load;
}
template <typename T>
static void init_instance_for_type(detail::instance *inst, const void *holder_const_void_ptr) {
// Need for const_cast is a consequence of the type_info::init_instance type:
// void (*init_instance)(instance *, const void *);
auto holder_void_ptr = const_cast<void *>(holder_const_void_ptr);
auto v_h = inst->get_value_and_holder(detail::get_type_info(typeid(T)));
if (!v_h.instance_registered()) {
register_instance(inst, v_h.value_ptr(), v_h.type);
v_h.set_instance_registered();
}
using holder_type = pybindit::memory::smart_holder;
if (holder_void_ptr) {
// Note: inst->owned ignored.
auto holder_ptr = static_cast<holder_type *>(holder_void_ptr);
new (std::addressof(v_h.holder<holder_type>())) holder_type(std::move(*holder_ptr));
} else if (inst->owned) {
new (std::addressof(v_h.holder<holder_type>()))
holder_type(holder_type::from_raw_ptr_take_ownership(v_h.value_ptr<T>()));
} else {
new (std::addressof(v_h.holder<holder_type>()))
holder_type(holder_type::from_raw_ptr_unowned(v_h.value_ptr<T>()));
}
v_h.set_holder_constructed();
}
};
template <typename T>
struct smart_holder_type_caster_load {
using holder_type = pybindit::memory::smart_holder;
bool load(handle src, bool convert) {
load_impl = modified_type_caster_generic_load_impl(typeid(T));
if (!load_impl.load(src, convert))
return false;
return true;
}
T *loaded_as_raw_ptr_unowned() const {
return convert_type(holder().template as_raw_ptr_unowned<void>());
}
T &loaded_as_lvalue_ref() const {
static const char *context = "loaded_as_lvalue_ref";
holder().ensure_is_populated(context);
holder().ensure_has_pointee(context);
return *loaded_as_raw_ptr_unowned();
}
T &&loaded_as_rvalue_ref() const {
static const char *context = "loaded_as_rvalue_ref";
holder().ensure_is_populated(context);
holder().ensure_has_pointee(context);
return std::move(*loaded_as_raw_ptr_unowned());
}
std::shared_ptr<T> loaded_as_shared_ptr() {
std::shared_ptr<void> void_ptr = holder().template as_shared_ptr<void>();
return std::shared_ptr<T>(void_ptr, convert_type(void_ptr.get()));
}
template <typename D = std::default_delete<T>>
std::unique_ptr<T, D> loaded_as_unique_ptr(const char *context = "loaded_as_unique_ptr") {
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>();
// MISSING: Safety checks for type conversions
// (T must be polymorphic or meet certain other conditions).
T *raw_type_ptr = convert_type(raw_void_ptr);
// Critical transfer-of-ownership section. This must stay together.
holder().release_ownership();
auto result = std::unique_ptr<T, D>(raw_type_ptr);
void *value_void_ptr
= load_impl.loaded_v_h.value_ptr(); // Expected to be identical to raw_void_ptr.
load_impl.loaded_v_h.holder<holder_type>().~holder_type();
load_impl.loaded_v_h.set_holder_constructed(false);
load_impl.loaded_v_h.value_ptr() = nullptr;
deregister_instance(load_impl.loaded_v_h.inst, value_void_ptr, load_impl.loaded_v_h.type);
return result;
}
private:
modified_type_caster_generic_load_impl load_impl;
holder_type &holder() const { return load_impl.loaded_v_h.holder<holder_type>(); }
T *convert_type(void *void_ptr) const {
if (void_ptr != nullptr && load_impl.loaded_v_h_cpptype != nullptr
&& !load_impl.reinterpret_cast_deemed_ok && load_impl.implicit_cast != nullptr) {
void_ptr = load_impl.implicit_cast(void_ptr);
}
return static_cast<T *>(void_ptr);
}
};
// IMPROVABLE: Formally factor out of type_caster_base.
struct make_constructor : private type_caster_base<int> { // Any type, nothing special about int.
using type_caster_base<int>::Constructor;
using type_caster_base<int>::make_copy_constructor;
using type_caster_base<int>::make_move_constructor;
};
template <typename T>
struct smart_holder_type_caster : smart_holder_type_caster_load<T>,
smart_holder_type_caster_class_hooks {
static constexpr auto name = _<T>();
// static handle cast(T, ...)
// is redundant (leads to ambiguous overloads).
static handle cast(T &&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(T 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(T &src, return_value_policy policy, handle parent) {
return cast(const_cast<T const &>(src), policy, parent); // Mutbl2Const
}
static handle cast(T const *src, return_value_policy policy, handle parent) {
auto st = type_caster_base<T>::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(T *src, return_value_policy policy, handle parent) {
return cast(const_cast<T const *>(src), policy, parent); // Mutbl2Const
}
template <typename T_>
using cast_op_type = conditional_t<
std::is_same<remove_reference_t<T_>, T const *>::value,
T const *,
conditional_t<
std::is_same<remove_reference_t<T_>, T *>::value,
T *,
conditional_t<std::is_same<T_, T const &>::value,
T const &,
conditional_t<std::is_same<T_, T &>::value,
T &,
conditional_t<std::is_same<T_, T &&>::value, T &&, T>>>>>;
// clang-format off
operator T() { return this->loaded_as_lvalue_ref(); }
operator T&&() && { return this->loaded_as_rvalue_ref(); }
operator T const&() { return this->loaded_as_lvalue_ref(); }
operator T&() { return this->loaded_as_lvalue_ref(); }
operator T const*() { return this->loaded_as_raw_ptr_unowned(); }
operator T*() { return this->loaded_as_raw_ptr_unowned(); }
// 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();
if (handle existing_inst = find_registered_python_instance(src, tinfo))
return existing_inst;
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 <typename T>
struct smart_holder_type_caster<std::shared_ptr<T>> : smart_holder_type_caster_load<T>,
smart_holder_type_caster_class_hooks {
static constexpr auto name = _<std::shared_ptr<T>>();
static handle cast(const std::shared_ptr<T> &src, return_value_policy policy, handle parent) {
if (policy != return_value_policy::automatic
&& policy != return_value_policy::reference_internal) {
// IMPROVABLE: Error message.
throw cast_error("Invalid return_value_policy for shared_ptr.");
}
auto src_raw_ptr = src.get();
auto st = type_caster_base<T>::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;
if (handle existing_inst = find_registered_python_instance(src_raw_void_ptr, tinfo))
// MISSING: Enforcement of consistency with existing smart_holder.
// 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(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<T>;
operator std::shared_ptr<T>() { return this->loaded_as_shared_ptr(); }
};
template <typename T>
struct smart_holder_type_caster<std::shared_ptr<T const>> : smart_holder_type_caster_load<T>,
smart_holder_type_caster_class_hooks {
static constexpr auto name = _<std::shared_ptr<T const>>();
static handle
cast(const std::shared_ptr<T const> &src, return_value_policy policy, handle parent) {
return smart_holder_type_caster<std::shared_ptr<T>>::cast(
std::const_pointer_cast<T>(src), // Const2Mutbl
policy,
parent);
}
template <typename>
using cast_op_type = std::shared_ptr<T const>;
operator std::shared_ptr<T const>() { return this->loaded_as_shared_ptr(); } // Mutbl2Const
};
template <typename T, typename D>
struct smart_holder_type_caster<std::unique_ptr<T, D>> : smart_holder_type_caster_load<T>,
smart_holder_type_caster_class_hooks {
static constexpr auto name = _<std::unique_ptr<T, D>>();
static handle cast(std::unique_ptr<T, D> &&src, return_value_policy policy, handle parent) {
if (policy != return_value_policy::automatic
&& policy != return_value_policy::reference_internal) {
// IMPROVABLE: Error message.
throw cast_error("Invalid return_value_policy for unique_ptr.");
}
auto src_raw_ptr = src.get();
auto st = type_caster_base<T>::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;
if (find_registered_python_instance(src_raw_void_ptr, tinfo))
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;
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<T, D>;
operator std::unique_ptr<T, D>() { return this->template loaded_as_unique_ptr<D>(); }
};
template <typename T, typename D>
struct smart_holder_type_caster<std::unique_ptr<T const, D>>
: smart_holder_type_caster_load<T>, smart_holder_type_caster_class_hooks {
static constexpr auto name = _<std::unique_ptr<T const, D>>();
static handle
cast(std::unique_ptr<T const, D> &&src, return_value_policy policy, handle parent) {
return smart_holder_type_caster<std::unique_ptr<T, D>>::cast(
std::unique_ptr<T, D>(const_cast<T *>(src.release())), // Const2Mutbl
policy,
parent);
}
template <typename>
using cast_op_type = std::unique_ptr<T const, D>;
operator std::unique_ptr<T const, D>() { return this->template loaded_as_unique_ptr<D>(); }
};
#define PYBIND11_SMART_HOLDER_TYPE_CASTERS(T) \
namespace pybind11 { \
namespace detail { \
template <> \
class type_caster<T> : public smart_holder_type_caster<T> {}; \
template <> \
class type_caster<std::shared_ptr<T>> : public smart_holder_type_caster<std::shared_ptr<T>> { \
}; \
template <> \
class type_caster<std::shared_ptr<T const>> \
: public smart_holder_type_caster<std::shared_ptr<T const>> {}; \
template <typename D> \
class type_caster<std::unique_ptr<T, D>> \
: public smart_holder_type_caster<std::unique_ptr<T, D>> {}; \
template <typename D> \
class type_caster<std::unique_ptr<T const, D>> \
: public smart_holder_type_caster<std::unique_ptr<T const, D>> {}; \
} \
}
} // namespace detail
} // namespace pybind11
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