OTS/OTSCPP/Tools/boost/outcome/experimental/status-code/status_code_ptr.hpp

/* Pointer to a SG14 status_code
(C) 2018-2020 Niall Douglas <http://www.nedproductions.biz/> (5 commits)
File Created: Sep 2018


Boost Software License - Version 1.0 - August 17th, 2003

Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
this license (the "Software") to use, reproduce, display, distribute,
execute, and transmit the Software, and to prepare derivative works of the
Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:

The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
a source language processor.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/

#ifndef BOOST_OUTCOME_SYSTEM_ERROR2_STATUS_CODE_PTR_HPP
#define BOOST_OUTCOME_SYSTEM_ERROR2_STATUS_CODE_PTR_HPP

#include "status_code.hpp"

BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_BEGIN

namespace detail
{
  template <class StatusCode> class indirecting_domain : public status_code_domain
  {
    template <class DomainType> friend class status_code;
    using _base = status_code_domain;

  public:
    using value_type = StatusCode *;
    using _base::string_ref;

    constexpr indirecting_domain() noexcept
        : _base(0xc44f7bdeb2cc50e9 ^ typename StatusCode::domain_type().id() /* unique-ish based on domain's unique id */)
    {
    }
    indirecting_domain(const indirecting_domain &) = default;
    indirecting_domain(indirecting_domain &&) = default;  // NOLINT
    indirecting_domain &operator=(const indirecting_domain &) = default;
    indirecting_domain &operator=(indirecting_domain &&) = default;  // NOLINT
    ~indirecting_domain() = default;

#if __cplusplus < 201402L && !defined(_MSC_VER)
    static inline const indirecting_domain &get()
    {
      static indirecting_domain v;
      return v;
    }
#else
    static inline constexpr const indirecting_domain &get();
#endif

    virtual string_ref name() const noexcept override { return typename StatusCode::domain_type().name(); }  // NOLINT
  protected:
    using _mycode = status_code<indirecting_domain>;
    virtual bool _do_failure(const status_code<void> &code) const noexcept override  // NOLINT
    {
      assert(code.domain() == *this);
      const auto &c = static_cast<const _mycode &>(code);  // NOLINT
      return typename StatusCode::domain_type()._do_failure(*c.value());
    }
    virtual bool _do_equivalent(const status_code<void> &code1, const status_code<void> &code2) const noexcept override  // NOLINT
    {
      assert(code1.domain() == *this);
      const auto &c1 = static_cast<const _mycode &>(code1);  // NOLINT
      return typename StatusCode::domain_type()._do_equivalent(*c1.value(), code2);
    }
    virtual generic_code _generic_code(const status_code<void> &code) const noexcept override  // NOLINT
    {
      assert(code.domain() == *this);
      const auto &c = static_cast<const _mycode &>(code);  // NOLINT
      return typename StatusCode::domain_type()._generic_code(*c.value());
    }
    virtual string_ref _do_message(const status_code<void> &code) const noexcept override  // NOLINT
    {
      assert(code.domain() == *this);
      const auto &c = static_cast<const _mycode &>(code);  // NOLINT
      return typename StatusCode::domain_type()._do_message(*c.value());
    }
#if defined(_CPPUNWIND) || defined(__EXCEPTIONS) || defined(BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE)
    BOOST_OUTCOME_SYSTEM_ERROR2_NORETURN virtual void _do_throw_exception(const status_code<void> &code) const override  // NOLINT
    {
      assert(code.domain() == *this);
      const auto &c = static_cast<const _mycode &>(code);  // NOLINT
      typename StatusCode::domain_type()._do_throw_exception(*c.value());
    }
#endif
    virtual void _do_erased_copy(status_code<void> &dst, const status_code<void> &src, size_t /*unused*/) const override  // NOLINT
    {
      assert(dst.domain() == *this);
      assert(src.domain() == *this);
      auto &d = static_cast<_mycode &>(dst);               // NOLINT
      const auto &_s = static_cast<const _mycode &>(src);  // NOLINT
      const StatusCode &s = *_s.value();
      new(&d) _mycode(in_place, new StatusCode(s));
    }
    virtual void _do_erased_destroy(status_code<void> &code, size_t /*unused*/) const noexcept override  // NOLINT
    {
      assert(code.domain() == *this);
      auto &c = static_cast<_mycode &>(code);  // NOLINT
      delete c.value();                        // NOLINT
    }
  };
#if __cplusplus >= 201402L || defined(_MSC_VER)
  template <class StatusCode> constexpr indirecting_domain<StatusCode> _indirecting_domain{};
  template <class StatusCode> inline constexpr const indirecting_domain<StatusCode> &indirecting_domain<StatusCode>::get() { return _indirecting_domain<StatusCode>; }
#endif
}  // namespace detail

/*! Make an erased status code which indirects to a dynamically allocated status code.
This is useful for shoehorning a rich status code with large value type into a small
erased status code like `system_code`, with which the status code generated by this
function is compatible. Note that this function can throw due to `bad_alloc`.
*/
template <class T, typename std::enable_if<is_status_code<T>::value, bool>::type = true>  //
inline status_code<erased<typename std::add_pointer<typename std::decay<T>::type>::type>> make_status_code_ptr(T &&v)
{
  using status_code_type = typename std::decay<T>::type;
  return status_code<detail::indirecting_domain<status_code_type>>(in_place, new status_code_type(static_cast<T &&>(v)));
}

/*! If a status code refers to a `status_code_ptr` which indirects to a status
code of type `StatusCode`, return a pointer to that `StatusCode`. Otherwise return null.
*/
template <class StatusCode, class U, typename std::enable_if<is_status_code<StatusCode>::value, bool>::type = true> inline StatusCode *get_if(status_code<erased<U>> *v) noexcept
{
  if((0xc44f7bdeb2cc50e9 ^ typename StatusCode::domain_type().id()) != v->domain().id())
  {
    return nullptr;
  }
  union {
    U value;
    StatusCode *ret;
  };
  value = v->value();
  return ret;
}
//! \overload Const overload
template <class StatusCode, class U, typename std::enable_if<is_status_code<StatusCode>::value, bool>::type = true> inline const StatusCode *get_if(const status_code<erased<U>> *v) noexcept
{
  if((0xc44f7bdeb2cc50e9 ^ typename StatusCode::domain_type().id()) != v->domain().id())
  {
    return nullptr;
  }
  union {
    U value;
    const StatusCode *ret;
  };
  value = v->value();
  return ret;
}

/*! If a status code refers to a `status_code_ptr`, return the id of the erased
status code's domain. Otherwise return a meaningless number.
*/
template <class U> inline typename status_code_domain::unique_id_type get_id(const status_code<erased<U>> &v) noexcept
{
  return 0xc44f7bdeb2cc50e9 ^ v.domain().id();
}

BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_END

#endif