EQ2EMu/EQ2/source/depends/boost_1_72_0/libs/outcome/test/tests/hooks.cpp

/* Unit testing for outcomes
(C) 2013-2019 Niall Douglas <http://www.nedproductions.biz/> (14 commits)


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

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*/

#define _CRT_SECURE_NO_WARNINGS

#include <boost/outcome/outcome.hpp>
#include <boost/test/unit_test.hpp>
#include <boost/test/unit_test_monitor.hpp>

#include <iostream>

namespace hook_test
{
  using BOOST_OUTCOME_V2_NAMESPACE::in_place_type;
  // Use static storage to convey extended error info from result construction to outcome conversion
  static char extended_error_info[256];

  // Use the error_code type as the ADL bridge for the hooks by creating a type here
  struct error_code : public boost::system::error_code
  {
    using boost::system::error_code::error_code;
    error_code() = default;
    error_code(boost::system::error_code ec)  // NOLINT
    : boost::system::error_code(ec)
    {
    }
  };
  // Localise result to using the local error_code so this namespace gets looked up for the hooks
  template <class R> using result = BOOST_OUTCOME_V2_NAMESPACE::result<R, error_code>;
  // Specialise the result construction hook for our localised result
  template <class U> constexpr inline void hook_result_construction(result<int> *res, U && /*unused*/) noexcept
  {
    // Write the value in the result into the static storage
    snprintf(extended_error_info, sizeof(extended_error_info), "%d", res->assume_value());  // NOLINT
  }
  template <class U> constexpr inline void hook_result_construction(result<std::string> *res, U && /*unused*/) noexcept
  {
    // Write the value in the result into the static storage
    snprintf(extended_error_info, sizeof(extended_error_info), "%s", res->assume_value().c_str());  // NOLINT
  }
}  // namespace hook_test

BOOST_OUTCOME_AUTO_TEST_CASE(works_result_hooks, "Tests that you can hook result's construction")
{
  using namespace hook_test;
  result<int> a(5);
  BOOST_CHECK(!strcmp(extended_error_info, "5"));  // NOLINT
  result<std::string> b("niall");
  BOOST_CHECK(!strcmp(extended_error_info, "niall"));  // NOLINT
}

//! [extended_error_coding2]
namespace hook_test
{
  // Localise outcome to using the local error_code so this namespace gets looked up for the hooks
  template <class R> using outcome = BOOST_OUTCOME_V2_NAMESPACE::outcome<R, error_code, std::string>;

  // Specialise the outcome copy and move conversion hook for our localised result
  template <class T, class U> constexpr inline void hook_outcome_copy_construction(outcome<T> *res, const result<U> & /*unused*/) noexcept
  {
    // when copy constructing from a result<T>, place extended_error_coding::extended_error_info into the payload
    std::cout << "hook_outcome_copy_construction fires" << std::endl;
    BOOST_OUTCOME_V2_NAMESPACE::hooks::override_outcome_exception(res, extended_error_info);
  }
  template <class T, class U> constexpr inline void hook_outcome_move_construction(outcome<T> *res, result<U> && /*unused*/) noexcept
  {
    // when move constructing from a result<T>, place extended_error_coding::extended_error_info into the payload
    std::cout << "hook_outcome_move_construction fires" << std::endl;
    BOOST_OUTCOME_V2_NAMESPACE::hooks::override_outcome_exception(res, extended_error_info);
  }
}  // namespace hook_test

BOOST_OUTCOME_AUTO_TEST_CASE(works_outcome_hooks, "Tests that you can hook outcome's conversion from a result")
{
  using namespace hook_test;
  outcome<int> a(result<int>(5));
  BOOST_REQUIRE(a.has_exception());  // NOLINT
  BOOST_CHECK(a.exception() == "5");
  outcome<std::string> b(result<std::string>("niall"));
  BOOST_CHECK(b.exception() == "niall");

  // Make sure hook does not fire for any other kind of outcome copy or move, only when converting from our custom result only
  outcome<int> c(5);
  outcome<long> d(c);  // can't be the same type as source, else copy elision takes place and no ADL hook calling
  BOOST_CHECK(!d.has_exception());
  outcome<int> e(BOOST_OUTCOME_V2_NAMESPACE::result<int>(5));
  BOOST_CHECK(!e.has_exception());
}