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Replacing virtual guarded_operator_call with non-virtual guarded_delete.

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Ralf W. Grosse-Kunstleve 2021-06-16 15:12:48 -07:00 committed by Ralf W. Grosse-Kunstleve
parent 1e6cc9dd69
commit cd5fbc56db
1 changed files with 23 additions and 49 deletions
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72
include/pybind11/detail/smart_holder_poc.h
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@ -56,33 +56,14 @@ Details:
namespace pybindit {
namespace memory {
struct guarded_operator_call {
struct guarded_delete {
void (*del_ptr)(void *);
bool armed_flag;
explicit guarded_operator_call(bool armed_flag) : armed_flag{armed_flag} {}
virtual void operator()(void *) = 0;
virtual ~guarded_operator_call() = default;
// Some compilers complain if the implicitly defined copy constructor is used.
guarded_operator_call(const guarded_operator_call &) = default;
};
template <typename T>
struct guarded_builtin_delete : guarded_operator_call {
explicit guarded_builtin_delete(bool armed_flag) : guarded_operator_call{armed_flag} {}
void operator()(void *raw_ptr) override { delete_impl<T>(raw_ptr); }
template <typename T_ = T,
typename std::enable_if<std::is_destructible<T_>::value, int>::type = 0>
void delete_impl(void *raw_ptr) {
guarded_delete(void (*del_ptr)(void *), bool armed_flag)
: del_ptr{del_ptr}, armed_flag{armed_flag} {}
void operator()(void *raw_ptr) const {
if (armed_flag)
delete (T *) raw_ptr;
}
template <typename T_ = T,
typename std::enable_if<!std::is_destructible<T_>::value, int>::type = 0>
void delete_impl(void *) {
// This noop operator is needed to avoid a compilation error (for `delete raw_ptr;`), but
// throwing an exception from here could std::terminate the process. Therefore the runtime
// check for lifetime-management correctness is implemented elsewhere (in
// ensure_pointee_is_destructible()).
(*del_ptr)(raw_ptr);
}
};
@ -105,12 +86,13 @@ guarded_delete make_guarded_builtin_delete(bool armed_flag) {
}
template <typename T, typename D>
struct guarded_custom_deleter : guarded_operator_call {
explicit guarded_custom_deleter(bool armed_flag) : guarded_operator_call{armed_flag} {}
void operator()(void *raw_ptr) override {
if (armed_flag)
D()((T *) raw_ptr);
}
inline void custom_delete(void *raw_ptr) {
D()((T *) raw_ptr);
}
template <typename T, typename D>
guarded_delete make_guarded_custom_deleter(bool armed_flag) {
return guarded_delete(custom_delete<T, D>, armed_flag);
};
template <typename T>
@ -121,7 +103,6 @@ inline bool is_std_default_delete(const std::type_info &rtti_deleter) {
struct smart_holder {
const std::type_info *rtti_uqp_del = nullptr;
guarded_operator_call *vptr_del = nullptr;
std::shared_ptr<void> vptr;
bool vptr_is_using_noop_deleter : 1;
bool vptr_is_using_builtin_delete : 1;
@ -213,25 +194,20 @@ struct smart_holder {
}
}
template <typename T, typename D>
void vptr_reset(T *raw_ptr, const D &del) {
vptr.reset(raw_ptr, del); // Copies del.
// The const_cast is only for certain compilers (Ubuntu 20 GCC 6.3.0 being one).
vptr_del = const_cast<D *>(std::get_deleter<D>(vptr)); // Pointer to copy of del.
}
void reset_vptr_deleter_armed_flag(bool armed_flag) const {
if (vptr_del == nullptr) {
// The const_cast is only for certain compilers (Ubuntu 20 GCC 6.3.0 being one).
auto vptr_del_ptr = const_cast<guarded_delete *>(std::get_deleter<guarded_delete>(vptr));
if (vptr_del_ptr == nullptr) {
throw std::runtime_error(
"smart_holder::reset_vptr_deleter_armed_flag() called in an invalid context.");
}
vptr_del->armed_flag = armed_flag;
vptr_del_ptr->armed_flag = armed_flag;
}
template <typename T>
static smart_holder from_raw_ptr_unowned(T *raw_ptr) {
smart_holder hld;
hld.vptr_reset(raw_ptr, guarded_builtin_delete<T>(false));
hld.vptr.reset(raw_ptr, [](void *) {});
hld.vptr_is_using_noop_deleter = true;
hld.is_populated = true;
return hld;
@ -262,7 +238,7 @@ struct smart_holder {
static smart_holder from_raw_ptr_take_ownership(T *raw_ptr) {
ensure_pointee_is_destructible<T>("from_raw_ptr_take_ownership");
smart_holder hld;
hld.vptr_reset(raw_ptr, guarded_builtin_delete<T>(true));
hld.vptr.reset(raw_ptr, make_guarded_builtin_delete<T>(true));
hld.vptr_is_using_builtin_delete = true;
hld.is_populated = true;
return hld;
@ -281,10 +257,7 @@ struct smart_holder {
}
// Caller is responsible for ensuring preconditions (SMART_HOLDER_WIP: details).
void release_disowned() {
vptr.reset();
vptr_del = nullptr;
}
void release_disowned() { vptr.reset(); }
// SMART_HOLDER_WIP: review this function.
void ensure_can_release_ownership(const char *context = "ensure_can_release_ownership") const {
@ -313,9 +286,10 @@ struct smart_holder {
hld.rtti_uqp_del = &typeid(D);
hld.vptr_is_using_builtin_delete = is_std_default_delete<T>(*hld.rtti_uqp_del);
if (hld.vptr_is_using_builtin_delete) {
hld.vptr_reset(unq_ptr.get(), guarded_builtin_delete<T>(true));
hld.vptr.reset(unq_ptr.get(), make_guarded_builtin_delete<T>(true));
} else {
hld.vptr_reset(unq_ptr.get(), guarded_custom_deleter<T, D>(true));
make_guarded_custom_deleter<T, D>(false);
hld.vptr.reset(unq_ptr.get(), make_guarded_custom_deleter<T, D>(true));
}
unq_ptr.release();
hld.is_populated = true;