f599e7a789
This patch fixes the constrains on the __perfect_forward constructor and its call operators, which were incorrect. In particular, it makes sure that we closely follow [func.require], which basically says that we must deliver the bound arguments with the appropriate value category or make the call ill-formed, but not silently fall back to using a different value category. As a fly-by, this patch also: - Adds types __bind_front_t and __not_fn_t to make the result of calling bind_front and not_fn more opaque, and improve diagnostics for users. - Adds a bunch of tests for bind_front and remove some that are now redundant. - Adds some missing _LIBCPP_HIDE_FROM_ABI annotations. Immense thanks to @tcanens for raising awareness about this issue, and providing help with the = delete bits. Differential Revision: https://reviews.llvm.org/D107199
59 lines
1.9 KiB
C++
59 lines
1.9 KiB
C++
// -*- C++ -*-
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef _LIBCPP___FUNCTIONAL_BIND_FRONT_H
|
|
#define _LIBCPP___FUNCTIONAL_BIND_FRONT_H
|
|
|
|
#include <__config>
|
|
#include <__functional/perfect_forward.h>
|
|
#include <__functional/invoke.h>
|
|
#include <type_traits>
|
|
#include <utility>
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
#pragma GCC system_header
|
|
#endif
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_STD
|
|
|
|
#if _LIBCPP_STD_VER > 17
|
|
|
|
struct __bind_front_op {
|
|
template <class ..._Args>
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr auto operator()(_Args&& ...__args) const
|
|
noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Args>(__args)...)))
|
|
-> decltype( _VSTD::invoke(_VSTD::forward<_Args>(__args)...))
|
|
{ return _VSTD::invoke(_VSTD::forward<_Args>(__args)...); }
|
|
};
|
|
|
|
template <class _Fn, class ..._BoundArgs>
|
|
struct __bind_front_t : __perfect_forward<__bind_front_op, _Fn, _BoundArgs...> {
|
|
using __perfect_forward<__bind_front_op, _Fn, _BoundArgs...>::__perfect_forward;
|
|
};
|
|
|
|
template <class _Fn, class... _Args, class = _EnableIf<
|
|
_And<
|
|
is_constructible<decay_t<_Fn>, _Fn>,
|
|
is_move_constructible<decay_t<_Fn>>,
|
|
is_constructible<decay_t<_Args>, _Args>...,
|
|
is_move_constructible<decay_t<_Args>>...
|
|
>::value
|
|
>>
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr auto bind_front(_Fn&& __f, _Args&&... __args) {
|
|
return __bind_front_t<decay_t<_Fn>, decay_t<_Args>...>(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
|
|
}
|
|
|
|
#endif // _LIBCPP_STD_VER > 17
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|
|
|
|
#endif // _LIBCPP___FUNCTIONAL_BIND_FRONT_H
|