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philnik777philnik777
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[libc++] Implement the public invoke API in terms of the libc++-internal API (#146334)
This adds one additional variable template to the libc++-internal API. This allows us to implement the public API once instead of twice.
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‎libcxx/include/__type_traits/invoke.h

Lines changed: 40 additions & 74 deletions
Original file line numberDiff line numberDiff line change
@@ -42,19 +42,22 @@
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// return std::invoke_r(std::forward<Args>(args)...);
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// }
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//
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// template <class Ret, class Func, class... Args>
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// inline const bool __is_invocable_r_v = is_invocable_r_v<Ret, Func, Args...>;
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//
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// template <class Func, class... Args>
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// struct __is_invocable : is_invocable<Func, Args...> {};
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//
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// template <class Func, class... Args>
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// inline const bool __is_invocable_v = is_invocable_v<Func, Args...>;
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//
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// template <class Ret, class Func, class... Args>
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// inline const bool __is_invocable_r_v = is_invocable_r_v<Ret, Func, Args...>;
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//
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// template <class Func, class... Args>
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// inline const bool __is_nothrow_invocable_v = is_nothrow_invocable_v<Func, Args...>;
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//
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// template <class Func, class... Args>
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// inline const bool __is_nothrow_invocable_r_v = is_nothrow_invocable_r_v<Func, Args...>;
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//
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// template <class Func, class... Args>
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// struct __invoke_result : invoke_result {};
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//
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// template <class Func, class... Args>
@@ -126,46 +129,6 @@ template <class _Ret, class... _Args>
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inline const bool __is_nothrow_invocable_r_v =
127130
__is_nothrow_invocable_r_impl<__is_nothrow_invocable_v<_Args...>, _Ret, _Args...>;
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# if _LIBCPP_STD_VER >= 17
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// is_invocable
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template <class _Fn, class... _Args>
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struct _LIBCPP_NO_SPECIALIZATIONS is_invocable : bool_constant<__is_invocable_v<_Fn, _Args...> > {};
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template <class _Ret, class _Fn, class... _Args>
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struct _LIBCPP_NO_SPECIALIZATIONS is_invocable_r : bool_constant<__is_invocable_r_v<_Ret, _Fn, _Args...>> {};
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template <class _Fn, class... _Args>
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_LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_invocable_v = __is_invocable_v<_Fn, _Args...>;
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template <class _Ret, class _Fn, class... _Args>
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_LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_invocable_r_v = is_invocable_r<_Ret, _Fn, _Args...>::value;
144-
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// is_nothrow_invocable
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template <class _Fn, class... _Args>
148-
struct _LIBCPP_NO_SPECIALIZATIONS is_nothrow_invocable : bool_constant<__is_nothrow_invocable_v<_Fn, _Args...> > {};
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template <class _Ret, class _Fn, class... _Args>
151-
struct _LIBCPP_NO_SPECIALIZATIONS is_nothrow_invocable_r
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: integral_constant<bool, __is_nothrow_invocable_r_v<_Ret, _Fn, _Args...>> {};
153-
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template <class _Fn, class... _Args>
155-
_LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_nothrow_invocable_v = __is_nothrow_invocable_v<_Fn, _Args...>;
156-
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template <class _Ret, class _Fn, class... _Args>
158-
_LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_nothrow_invocable_r_v =
159-
__is_nothrow_invocable_r_v<_Ret, _Fn, _Args...>;
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template <class _Fn, class... _Args>
162-
struct _LIBCPP_NO_SPECIALIZATIONS invoke_result : __invoke_result<_Fn, _Args...> {};
163-
164-
template <class _Fn, class... _Args>
165-
using invoke_result_t = __invoke_result_t<_Fn, _Args...>;
166-
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# endif // _LIBCPP_STD_VER >= 17
168-
169132
#else // __has_builtin(__builtin_invoke)
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171134
template <class _DecayedFp>
@@ -352,19 +315,45 @@ inline const bool __is_invocable_r_v = __invokable_r<_Ret, _Func, _Args...>::val
352315
template <class _Func, class... _Args>
353316
inline const bool __is_nothrow_invocable_v = __nothrow_invokable<_Func, _Args...>::value;
354317

318+
template <class _Ret, class _Func, class... _Args>
319+
inline const bool __is_nothrow_invocable_r_v = __nothrow_invokable_r<_Ret, _Func, _Args...>::value;
320+
355321
template <class _Func, class... _Args>
356322
struct __invoke_result
357323
: enable_if<__is_invocable_v<_Func, _Args...>, typename __invokable_r<void, _Func, _Args...>::_Result> {};
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359325
template <class _Func, class... _Args>
360326
using __invoke_result_t _LIBCPP_NODEBUG = typename __invoke_result<_Func, _Args...>::type;
361327

362-
# if _LIBCPP_STD_VER >= 17
328+
#endif // __has_builtin(__builtin_invoke_r)
329+
330+
template <class _Ret, bool = is_void<_Ret>::value>
331+
struct __invoke_void_return_wrapper {
332+
template <class... _Args>
333+
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static _Ret __call(_Args&&... __args) {
334+
return std::__invoke(std::forward<_Args>(__args)...);
335+
}
336+
};
337+
338+
template <class _Ret>
339+
struct __invoke_void_return_wrapper<_Ret, true> {
340+
template <class... _Args>
341+
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static void __call(_Args&&... __args) {
342+
std::__invoke(std::forward<_Args>(__args)...);
343+
}
344+
};
345+
346+
template <class _Ret, class... _Args>
347+
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Ret __invoke_r(_Args&&... __args) {
348+
return __invoke_void_return_wrapper<_Ret>::__call(std::forward<_Args>(__args)...);
349+
}
350+
351+
#if _LIBCPP_STD_VER >= 17
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364353
// is_invocable
365354

366355
template <class _Fn, class... _Args>
367-
struct _LIBCPP_NO_SPECIALIZATIONS is_invocable : bool_constant<__is_invocable_v<_Fn, _Args...>> {};
356+
struct _LIBCPP_NO_SPECIALIZATIONS is_invocable : bool_constant<__is_invocable_v<_Fn, _Args...> > {};
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369358
template <class _Ret, class _Fn, class... _Args>
370359
struct _LIBCPP_NO_SPECIALIZATIONS is_invocable_r : bool_constant<__is_invocable_r_v<_Ret, _Fn, _Args...>> {};
@@ -378,49 +367,26 @@ _LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_invocable_r_v = __is_invocab
378367
// is_nothrow_invocable
379368

380369
template <class _Fn, class... _Args>
381-
struct _LIBCPP_NO_SPECIALIZATIONS is_nothrow_invocable : bool_constant<__nothrow_invokable<_Fn, _Args...>::value> {};
370+
struct _LIBCPP_NO_SPECIALIZATIONS is_nothrow_invocable : bool_constant<__is_nothrow_invocable_v<_Fn, _Args...> > {};
382371

383372
template <class _Ret, class _Fn, class... _Args>
384373
struct _LIBCPP_NO_SPECIALIZATIONS is_nothrow_invocable_r
385-
: bool_constant<__nothrow_invokable_r<_Ret, _Fn, _Args...>::value> {};
374+
: bool_constant<__is_nothrow_invocable_r_v<_Ret, _Fn, _Args...>> {};
386375

387376
template <class _Fn, class... _Args>
388-
_LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_nothrow_invocable_v = is_nothrow_invocable<_Fn, _Args...>::value;
377+
_LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_nothrow_invocable_v = __is_nothrow_invocable_v<_Fn, _Args...>;
389378

390379
template <class _Ret, class _Fn, class... _Args>
391380
_LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_nothrow_invocable_r_v =
392-
is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
381+
__is_nothrow_invocable_r_v<_Ret, _Fn, _Args...>;
393382

394383
template <class _Fn, class... _Args>
395384
struct _LIBCPP_NO_SPECIALIZATIONS invoke_result : __invoke_result<_Fn, _Args...> {};
396385

397386
template <class _Fn, class... _Args>
398-
using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
399-
400-
# endif // _LIBCPP_STD_VER >= 17
401-
402-
#endif // __has_builtin(__builtin_invoke_r)
403-
404-
template <class _Ret, bool = is_void<_Ret>::value>
405-
struct __invoke_void_return_wrapper {
406-
template <class... _Args>
407-
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static _Ret __call(_Args&&... __args) {
408-
return std::__invoke(std::forward<_Args>(__args)...);
409-
}
410-
};
411-
412-
template <class _Ret>
413-
struct __invoke_void_return_wrapper<_Ret, true> {
414-
template <class... _Args>
415-
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static void __call(_Args&&... __args) {
416-
std::__invoke(std::forward<_Args>(__args)...);
417-
}
418-
};
387+
using invoke_result_t = __invoke_result_t<_Fn, _Args...>;
419388

420-
template <class _Ret, class... _Args>
421-
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Ret __invoke_r(_Args&&... __args) {
422-
return __invoke_void_return_wrapper<_Ret>::__call(std::forward<_Args>(__args)...);
423-
}
389+
#endif
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_LIBCPP_END_NAMESPACE_STD
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