/* Proposed SG14 status_code
(C) 2018-2020 Niall Douglas <http://www.nedproductions.biz/> (5 commits)
File Created: Feb 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,
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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
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*/

#ifndef BOOST_OUTCOME_SYSTEM_ERROR2_POSIX_CODE_HPP
#define BOOST_OUTCOME_SYSTEM_ERROR2_POSIX_CODE_HPP

#ifdef BOOST_OUTCOME_SYSTEM_ERROR2_NOT_POSIX
#error <posix_code.hpp> is not includable when BOOST_OUTCOME_SYSTEM_ERROR2_NOT_POSIX is defined!
#endif

#include "generic_code.hpp"

#include <cstring>  // for strchr and strerror_r

BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_BEGIN

class _posix_code_domain;
//! A POSIX error code, those returned by `errno`.
using posix_code = status_code<_posix_code_domain>;
//! A specialisation of `status_error` for the POSIX error code domain.
using posix_error = status_error<_posix_code_domain>;

/*! The implementation of the domain for POSIX error codes, those returned by `errno`.
*/
class _posix_code_domain : public status_code_domain
{
  template <class DomainType> friend class status_code;
  template <class StatusCode> friend class detail::indirecting_domain;
  using _base = status_code_domain;

  static _base::string_ref _make_string_ref(int c) noexcept
  {
    char buffer[1024] = "";
#ifdef _WIN32
    strerror_s(buffer, sizeof(buffer), c);
#elif defined(__gnu_linux__) && !defined(__ANDROID__)  // handle glibc's weird strerror_r()
    char *s = strerror_r(c, buffer, sizeof(buffer));   // NOLINT
    if(s != nullptr)
    {
      strncpy(buffer, s, sizeof(buffer));  // NOLINT
      buffer[1023] = 0;
    }
#else
    strerror_r(c, buffer, sizeof(buffer));
#endif
    size_t length = strlen(buffer);  // NOLINT
    auto *p = static_cast<char *>(malloc(length + 1));  // NOLINT
    if(p == nullptr)
    {
      return _base::string_ref("failed to get message from system");
    }
    memcpy(p, buffer, length + 1);  // NOLINT
    return _base::atomic_refcounted_string_ref(p, length);
  }

public:
  //! The value type of the POSIX code, which is an `int`
  using value_type = int;
  using _base::string_ref;

  //! Default constructor
  constexpr explicit _posix_code_domain(typename _base::unique_id_type id = 0xa59a56fe5f310933) noexcept : _base(id) {}
  _posix_code_domain(const _posix_code_domain &) = default;
  _posix_code_domain(_posix_code_domain &&) = default;
  _posix_code_domain &operator=(const _posix_code_domain &) = default;
  _posix_code_domain &operator=(_posix_code_domain &&) = default;
  ~_posix_code_domain() = default;

  //! Constexpr singleton getter. Returns constexpr posix_code_domain variable.
  static inline constexpr const _posix_code_domain &get();

  virtual string_ref name() const noexcept override { return string_ref("posix domain"); }  // NOLINT
protected:
  virtual bool _do_failure(const status_code<void> &code) const noexcept override  // NOLINT
  {
    assert(code.domain() == *this);  // NOLINT
    return static_cast<const posix_code &>(code).value() != 0;  // NOLINT
  }
  virtual bool _do_equivalent(const status_code<void> &code1, const status_code<void> &code2) const noexcept override  // NOLINT
  {
    assert(code1.domain() == *this);  // NOLINT
    const auto &c1 = static_cast<const posix_code &>(code1);  // NOLINT
    if(code2.domain() == *this)
    {
      const auto &c2 = static_cast<const posix_code &>(code2);  // NOLINT
      return c1.value() == c2.value();
    }
    if(code2.domain() == generic_code_domain)
    {
      const auto &c2 = static_cast<const generic_code &>(code2);  // NOLINT
      if(static_cast<int>(c2.value()) == c1.value())
      {
        return true;
      }
    }
    return false;
  }
  virtual generic_code _generic_code(const status_code<void> &code) const noexcept override  // NOLINT
  {
    assert(code.domain() == *this);  // NOLINT
    const auto &c = static_cast<const posix_code &>(code);  // NOLINT
    return generic_code(static_cast<errc>(c.value()));
  }
  virtual string_ref _do_message(const status_code<void> &code) const noexcept override  // NOLINT
  {
    assert(code.domain() == *this);  // NOLINT
    const auto &c = static_cast<const posix_code &>(code);  // NOLINT
    return _make_string_ref(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);  // NOLINT
    const auto &c = static_cast<const posix_code &>(code);  // NOLINT
    throw status_error<_posix_code_domain>(c);
  }
#endif
};
//! A constexpr source variable for the POSIX code domain, which is that of `errno`. Returned by `_posix_code_domain::get()`.
constexpr _posix_code_domain posix_code_domain;
inline constexpr const _posix_code_domain &_posix_code_domain::get()
{
  return posix_code_domain;
}

BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_END

#endif
