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Merge pull request #2176 from gracicot/cpp20-support-no-std-fct-templ-specialization

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C++20 support by removing swap specialization
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Niels Lohmann 2020-06-21 20:39:58 +02:00 committed by GitHub
commit 29ad2178c6
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5 changed files with 80 additions and 5 deletions
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6
include/nlohmann/detail/macro_scope.hpp
View file

@ -20,7 +20,11 @@
#endif
// C++ language standard detection
#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
#if (defined(__cplusplus) && __cplusplus >= 202002L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 202002L)
#define JSON_HAS_CPP_20
#define JSON_HAS_CPP_17
#define JSON_HAS_CPP_14
#elif (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
#define JSON_HAS_CPP_17
#define JSON_HAS_CPP_14
#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)

33
include/nlohmann/json.hpp
View file

@ -5865,6 +5865,34 @@ class basic_json
/*!
@brief exchanges the values
Exchanges the contents of the JSON value from @a left with those of @a right. Does not
invoke any move, copy, or swap operations on individual elements. All
iterators and references remain valid. The past-the-end iterator is
invalidated. implemented as a friend function callable via ADL.
@param[in,out] left JSON value to exchange the contents with
@param[in,out] right JSON value to exchange the contents with
@complexity Constant.
@liveexample{The example below shows how JSON values can be swapped with
`swap()`.,swap__reference}
@since version 1.0.0
*/
friend void swap(reference left, reference right) noexcept (
std::is_nothrow_move_constructible<value_t>::value and
std::is_nothrow_move_assignable<value_t>::value and
std::is_nothrow_move_constructible<json_value>::value and
std::is_nothrow_move_assignable<json_value>::value
)
{
left.swap(right);
}
/*!
@brief exchanges the values
Exchanges the contents of a JSON array with those of @a other. Does not
invoke any move, copy, or swap operations on individual elements. All
iterators and references remain valid. The past-the-end iterator is
@ -8657,6 +8685,9 @@ struct less<::nlohmann::detail::value_t>
}
};
// C++20 prohibit function specialization in the std namespace.
#ifndef JSON_HAS_CPP_20
/*!
@brief exchanges the values of two JSON objects
@ -8671,6 +8702,8 @@ inline void swap<nlohmann::json>(nlohmann::json& j1, nlohmann::json& j2) noexcep
j1.swap(j2);
}
#endif
} // namespace std
/*!

39
single_include/nlohmann/json.hpp
View file

@ -2048,7 +2048,11 @@ JSON_HEDLEY_DIAGNOSTIC_POP
#endif
// C++ language standard detection
#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
#if (defined(__cplusplus) && __cplusplus >= 202002L) || (defined(_MSVC_LANG) && _MSVC_LANG >= 202002L)
#define JSON_HAS_CPP_20
#define JSON_HAS_CPP_17
#define JSON_HAS_CPP_14
#elif (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
#define JSON_HAS_CPP_17
#define JSON_HAS_CPP_14
#elif (defined(__cplusplus) && __cplusplus >= 201402L) || (defined(_HAS_CXX14) && _HAS_CXX14 == 1)
@ -21655,6 +21659,34 @@ class basic_json
/*!
@brief exchanges the values
Exchanges the contents of the JSON value from @a left with those of @a right. Does not
invoke any move, copy, or swap operations on individual elements. All
iterators and references remain valid. The past-the-end iterator is
invalidated. implemented as a friend function callable via ADL.
@param[in,out] left JSON value to exchange the contents with
@param[in,out] right JSON value to exchange the contents with
@complexity Constant.
@liveexample{The example below shows how JSON values can be swapped with
`swap()`.,swap__reference}
@since version 1.0.0
*/
friend void swap(reference left, reference right) noexcept (
std::is_nothrow_move_constructible<value_t>::value and
std::is_nothrow_move_assignable<value_t>::value and
std::is_nothrow_move_constructible<json_value>::value and
std::is_nothrow_move_assignable<json_value>::value
)
{
left.swap(right);
}
/*!
@brief exchanges the values
Exchanges the contents of a JSON array with those of @a other. Does not
invoke any move, copy, or swap operations on individual elements. All
iterators and references remain valid. The past-the-end iterator is
@ -24447,6 +24479,9 @@ struct less<::nlohmann::detail::value_t>
}
};
// C++20 prohibit function specialization in the std namespace.
#ifndef JSON_HAS_CPP_20
/*!
@brief exchanges the values of two JSON objects
@ -24461,6 +24496,8 @@ inline void swap<nlohmann::json>(nlohmann::json& j1, nlohmann::json& j2) noexcep
j1.swap(j2);
}
#endif
} // namespace std
/*!

4
test/src/unit-concepts.cpp
View file

@ -154,7 +154,7 @@ TEST_CASE("concepts")
json j {1, 2, 3};
json::iterator it1 = j.begin();
json::iterator it2 = j.end();
std::swap(it1, it2);
swap(it1, it2);
CHECK(it1 == j.end());
CHECK(it2 == j.begin());
}
@ -162,7 +162,7 @@ TEST_CASE("concepts")
json j {1, 2, 3};
json::const_iterator it1 = j.cbegin();
json::const_iterator it2 = j.cend();
std::swap(it1, it2);
swap(it1, it2);
CHECK(it1 == j.end());
CHECK(it2 == j.begin());
}

3
test/src/unit-modifiers.cpp
View file

@ -878,7 +878,8 @@ TEST_CASE("modifiers")
json j("hello world");
json k(42.23);
std::swap(j, k);
using std::swap;
swap(j, k);
CHECK(j == json(42.23));
CHECK(k == json("hello world"));