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#pragma once
#include <cstddef> // for nullptr_t, NULL
#include <memory> // for bad_weak_ptr
#include <type_traits> // for add_lvalue_reference
#include "cpp11/R.hpp" // for SEXP, SEXPREC, R_NilValue
#include "cpp11/protect.hpp" // for protect, safe, protect::function
#include "cpp11/r_bool.hpp" // for r_bool
#include "cpp11/r_vector.hpp" // for type_error
#include "cpp11/sexp.hpp" // for sexp
namespace cpp11 {
template <typename T>
void default_deleter(T* obj) {
delete obj;
}
template <typename T, void Deleter(T*) = default_deleter<T>>
class external_pointer {
private:
sexp data_ = R_NilValue;
static SEXP valid_type(SEXP data) {
if (data == nullptr) {
throw type_error(EXTPTRSXP, NILSXP);
}
if (detail::r_typeof(data) != EXTPTRSXP) {
throw type_error(EXTPTRSXP, detail::r_typeof(data));
}
return data;
}
static void r_deleter(SEXP p) {
if (detail::r_typeof(p) != EXTPTRSXP) return;
T* ptr = static_cast<T*>(R_ExternalPtrAddr(p));
if (ptr == NULL) {
return;
}
R_ClearExternalPtr(p);
Deleter(ptr);
}
public:
using pointer = T*;
external_pointer() noexcept {}
external_pointer(std::nullptr_t) noexcept {}
external_pointer(SEXP data) : data_(valid_type(data)) {}
external_pointer(pointer p, bool use_deleter = true, bool finalize_on_exit = true)
: data_(safe[R_MakeExternalPtr]((void*)p, R_NilValue, R_NilValue)) {
if (use_deleter) {
R_RegisterCFinalizerEx(data_, r_deleter, static_cast<r_bool>(finalize_on_exit));
}
}
external_pointer(const external_pointer& rhs) {
data_ = safe[Rf_shallow_duplicate](rhs.data_);
}
external_pointer(external_pointer&& rhs) { reset(rhs.release()); }
external_pointer& operator=(external_pointer&& rhs) noexcept { reset(rhs.release()); }
external_pointer& operator=(std::nullptr_t) noexcept { reset(); };
operator SEXP() const noexcept { return data_; }
pointer get() const noexcept {
pointer addr = static_cast<T*>(R_ExternalPtrAddr(data_));
if (addr == nullptr) {
return nullptr;
}
return addr;
}
typename std::add_lvalue_reference<T>::type operator*() {
pointer addr = get();
if (addr == nullptr) {
throw std::bad_weak_ptr();
}
return *get();
}
pointer operator->() const {
pointer addr = get();
if (addr == nullptr) {
throw std::bad_weak_ptr();
}
return get();
}
pointer release() noexcept {
if (get() == nullptr) {
return nullptr;
}
pointer ptr = get();
R_ClearExternalPtr(data_);
return ptr;
}
void reset(pointer ptr = pointer()) {
SEXP old_data = data_;
data_ = safe[R_MakeExternalPtr]((void*)ptr, R_NilValue, R_NilValue);
r_deleter(old_data);
}
void swap(external_pointer& other) noexcept {
SEXP tmp = other.data_;
other.data_ = data_;
data_ = tmp;
}
operator bool() noexcept { return data_ != nullptr; }
};
template <class T, void Deleter(T*)>
void swap(external_pointer<T, Deleter>& lhs, external_pointer<T, Deleter>& rhs) noexcept {
lhs.swap(rhs);
}
template <class T, void Deleter(T*)>
bool operator==(const external_pointer<T, Deleter>& x,
const external_pointer<T, Deleter>& y) {
return x.data_ == y.data_;
}
template <class T, void Deleter(T*)>
bool operator!=(const external_pointer<T, Deleter>& x,
const external_pointer<T, Deleter>& y) {
return x.data_ != y.data_;
}
template <class T, void Deleter(T*)>
bool operator<(const external_pointer<T, Deleter>& x,
const external_pointer<T, Deleter>& y) {
return x.data_ < y.data_;
}
template <class T, void Deleter(T*)>
bool operator<=(const external_pointer<T, Deleter>& x,
const external_pointer<T, Deleter>& y) {
return x.data_ <= y.data_;
}
template <class T, void Deleter(T*)>
bool operator>(const external_pointer<T, Deleter>& x,
const external_pointer<T, Deleter>& y) {
return x.data_ > y.data_;
}
template <class T, void Deleter(T*)>
bool operator>=(const external_pointer<T, Deleter>& x,
const external_pointer<T, Deleter>& y) {
return x.data_ >= y.data_;
}
} // namespace cpp11
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