Snapshot of WIP, TODO: shared_ptr deleter with on/off switch

This commit is contained in:
Ralf W. Grosse-Kunstleve 2021-01-05 09:45:31 -08:00
parent 76e99f1c81
commit 72d1b61176
3 changed files with 115 additions and 0 deletions

View File

@ -0,0 +1,75 @@
#pragma once
#include <memory>
#include <typeinfo>
PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
struct smart_holder {
std::shared_ptr<void> vptr;
const std::type_info* rtti_held;
const std::type_info* rtti_uqp_del;
bool have_external_shp;
smart_holder()
: rtti_held{nullptr}, rtti_uqp_del{nullptr}, have_external_shp(false) {}
template <typename T>
void ensure_compatible_rtti(const char* context) {
const std::type_info* rtti_requested = &typeid(T);
if (!(*rtti_requested == *rtti_held)) {
throw std::runtime_error(std::string("Incompatible RTTI (") + context +
").");
}
}
void ensure_use_count_1(const char* context) {
if (vptr.use_count() != 1) {
throw std::runtime_error(std::string("Cannot disown use_count != 1 (") +
context + ").");
}
}
void ensure_unique_ptr_default_deleter(const char* context) {
if (rtti_uqp_del != nullptr) {
throw std::runtime_error(
std::string("Cannot disown unique_ptr deleter (") + context + ").");
}
}
void ensure_internal_shared_ptr(const char* context) {
if (have_external_shp) {
throw std::runtime_error(
std::string("Cannot disown external shared_ptr (") + context + ").");
}
}
template <typename T>
void from_raw_ptr_owned(T* raw_ptr) {
vptr.reset(raw_ptr);
rtti_held = &typeid(T);
}
template <typename T>
T* as_raw_ptr_owned() {
static const char* context = "as_raw_ptr_owned";
ensure_compatible_rtti<T>(context);
ensure_use_count_1(context);
ensure_unique_ptr_default_deleter(context);
ensure_internal_shared_ptr(context);
std::shared_ptr<T> tptr = std::static_pointer_cast<T>(vptr);
vptr.reset();
T* result = tptr.get();
// TODO tptr.release();
return result;
}
template <typename T>
std::shared_ptr<T> as_shared_ptr() {
static const char* context = "as_shared_ptr";
ensure_compatible_rtti<T>(context);
return std::static_pointer_cast<T>(vptr);
}
};
PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)

View File

@ -0,0 +1,32 @@
#include "pybind11_tests.h"
#include <pybind11/smart_holder_poc.h>
#include <iostream>
#include <string>
namespace pybind11_tests {
namespace smart_holder_poc {
inline void to_cout(std::string msg) { std::cout << msg << std::endl; }
inline void exercise() {
to_cout("");
namespace py = pybind11;
py::smart_holder hld;
hld.from_raw_ptr_owned(new int(13));
to_cout(hld.rtti_held->name());
{
std::shared_ptr<int> val = hld.as_shared_ptr<int>();
to_cout(std::to_string(*val));
}
{
std::unique_ptr<int> val(hld.as_raw_ptr_owned<int>());
to_cout(std::to_string(*val));
}
}
TEST_SUBMODULE(smart_holder_poc, m) { m.def("exercise", exercise); }
} // namespace smart_holder_poc
} // namespace pybind11_tests

View File

@ -0,0 +1,8 @@
# -*- coding: utf-8 -*-
import pytest
from pybind11_tests import smart_holder_poc as m
def test_exercise():
m.exercise()