Relations.cpp

#include "Module.h"
#include "Relations.h"

#include <cxxabi.h>

namespace steamlein
{
namespace detail {
// helper classes to walk type_info class structures
template <typename L>
void walk_tree(L const& l, std::type_info const& b);
template <typename L>
void walk_tree(L const& l, __cxxabiv1::__si_class_type_info const& si) {
    l(*si.__base_type);
    walk_tree(l, *si.__base_type);
}
template <typename L>
void walk_tree(L const& l, __cxxabiv1::__vmi_class_type_info const& mi) {
    for (unsigned int i {0}; i < mi.__base_count; ++i) {
        l(*mi.__base_info[i].__base_type);
    }
}
template <typename L>
void walk_tree(L const& l, std::type_info const& b) {
    if (auto si = dynamic_cast<const __cxxabiv1::__si_class_type_info*>(&b); si) {
        walk_tree(l, *si);
    } else if (auto mi = dynamic_cast<const __cxxabiv1::__vmi_class_type_info*>(&b); mi) {
        walk_tree(l, *mi);
    }
}

bool is_ancestor(std::type_info const& deriv, std::type_info const& base) {
    if (base == deriv) {
        return true;
    }
    bool found{false};
    walk_tree([&](auto const& info) {
        found |= (&info == &base);
    }, deriv);
    return found;
}

void const* manual_up_cast(void const* ptr, std::type_info const& deriv, std::type_info const& base) {
    if (deriv == base) {
        return ptr;
    }

    auto baseInfo =  dynamic_cast<__cxxabiv1::__class_type_info const*>(&base);

    if (not baseInfo) {
        return nullptr;
    }
    deriv.__do_upcast(baseInfo, const_cast<void**>(&ptr));
    return ptr;
}

}

Relation::Relation(Module* owner) {
    owner->addRelation(this);
}

}