368faacac7
This commit reverts 5aaefa51 (and also partly 7f285f48e77 and b6d75682f9, which were related to the original commit). As landed, 5aaefa51 had unintended consequences on some downstream bots and didn't have proper coverage upstream due to a few subtle things. Implementing this is something we should do in libc++, however we'll first need to address a few issues listed in https://reviews.llvm.org/D106124#3349710. Differential Revision: https://reviews.llvm.org/D120683
53 lines
2.1 KiB
C++
53 lines
2.1 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___FUNCTIONAL_COMPOSE_H
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#define _LIBCPP___FUNCTIONAL_COMPOSE_H
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#include <__config>
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#include <__functional/invoke.h>
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#include <__functional/perfect_forward.h>
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#include <__utility/forward.h>
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#include <type_traits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if _LIBCPP_STD_VER > 17
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struct __compose_op {
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template<class _Fn1, class _Fn2, class ..._Args>
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_LIBCPP_HIDE_FROM_ABI
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constexpr auto operator()(_Fn1&& __f1, _Fn2&& __f2, _Args&&... __args) const
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noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Fn1>(__f1), _VSTD::invoke(_VSTD::forward<_Fn2>(__f2), _VSTD::forward<_Args>(__args)...))))
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-> decltype( _VSTD::invoke(_VSTD::forward<_Fn1>(__f1), _VSTD::invoke(_VSTD::forward<_Fn2>(__f2), _VSTD::forward<_Args>(__args)...)))
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{ return _VSTD::invoke(_VSTD::forward<_Fn1>(__f1), _VSTD::invoke(_VSTD::forward<_Fn2>(__f2), _VSTD::forward<_Args>(__args)...)); }
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};
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template <class _Fn1, class _Fn2>
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struct __compose_t : __perfect_forward<__compose_op, _Fn1, _Fn2> {
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using __perfect_forward<__compose_op, _Fn1, _Fn2>::__perfect_forward;
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};
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template <class _Fn1, class _Fn2>
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_LIBCPP_HIDE_FROM_ABI
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constexpr auto __compose(_Fn1&& __f1, _Fn2&& __f2)
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noexcept(noexcept(__compose_t<decay_t<_Fn1>, decay_t<_Fn2>>(_VSTD::forward<_Fn1>(__f1), _VSTD::forward<_Fn2>(__f2))))
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-> decltype( __compose_t<decay_t<_Fn1>, decay_t<_Fn2>>(_VSTD::forward<_Fn1>(__f1), _VSTD::forward<_Fn2>(__f2)))
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{ return __compose_t<decay_t<_Fn1>, decay_t<_Fn2>>(_VSTD::forward<_Fn1>(__f1), _VSTD::forward<_Fn2>(__f2)); }
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#endif // _LIBCPP_STD_VER > 17
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___FUNCTIONAL_COMPOSE_H
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