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//===----------------------------------------------------------------------===//
//
// 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___UTILITY_TRY_EXTRACT_KEY_H
#define _LIBCPP___UTILITY_TRY_EXTRACT_KEY_H
#include <__config>
#include <__fwd/pair.h>
#include <__fwd/tuple.h>
#include <__type_traits/enable_if.h>
#include <__type_traits/is_same.h>
#include <__type_traits/remove_const.h>
#include <__type_traits/remove_const_ref.h>
#include <__utility/declval.h>
#include <__utility/forward.h>
#include <__utility/piecewise_construct.h>
#include <__utility/priority_tag.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _KeyT, class _Ret, class _WithKey, class _WithoutKey, class... _Args>
_LIBCPP_HIDE_FROM_ABI _Ret
__try_key_extraction_impl(__priority_tag<0>, _WithKey, _WithoutKey __without_key, _Args&&... __args) {
return __without_key(std::forward<_Args>(__args)...);
}
template <class _KeyT,
class _Ret,
class _WithKey,
class _WithoutKey,
class _Arg,
__enable_if_t<is_same<_KeyT, __remove_const_ref_t<_Arg> >::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _Ret
__try_key_extraction_impl(__priority_tag<1>, _WithKey __with_key, _WithoutKey, _Arg&& __arg) {
return __with_key(__arg, std::forward<_Arg>(__arg));
}
template <class _KeyT,
class _Ret,
class _WithKey,
class _WithoutKey,
class _Arg,
__enable_if_t<__is_pair_v<__remove_const_ref_t<_Arg> > &&
is_same<__remove_const_t<typename __remove_const_ref_t<_Arg>::first_type>, _KeyT>::value,
int> = 0>
_LIBCPP_HIDE_FROM_ABI _Ret
__try_key_extraction_impl(__priority_tag<1>, _WithKey __with_key, _WithoutKey, _Arg&& __arg) {
return __with_key(__arg.first, std::forward<_Arg>(__arg));
}
template <class _KeyT,
class _Ret,
class _WithKey,
class _WithoutKey,
class _Arg1,
class _Arg2,
__enable_if_t<is_same<_KeyT, __remove_const_ref_t<_Arg1> >::value, int> = 0>
_LIBCPP_HIDE_FROM_ABI _Ret
__try_key_extraction_impl(__priority_tag<1>, _WithKey __with_key, _WithoutKey, _Arg1&& __arg1, _Arg2&& __arg2) {
return __with_key(__arg1, std::forward<_Arg1>(__arg1), std::forward<_Arg2>(__arg2));
}
#ifndef _LIBCPP_CXX03_LANG
template <class _KeyT,
class _Ret,
class _WithKey,
class _WithoutKey,
class _PiecewiseConstruct,
class _Tuple1,
class _Tuple2,
__enable_if_t<is_same<__remove_const_ref_t<_PiecewiseConstruct>, piecewise_construct_t>::value &&
__is_tuple_v<_Tuple1> && tuple_size<_Tuple1>::value == 1 &&
is_same<__remove_const_ref_t<typename tuple_element<0, _Tuple1>::type>, _KeyT>::value,
int> = 0>
_LIBCPP_HIDE_FROM_ABI _Ret __try_key_extraction_impl(
__priority_tag<1>,
_WithKey __with_key,
_WithoutKey,
_PiecewiseConstruct&& __pc,
_Tuple1&& __tuple1,
_Tuple2&& __tuple2) {
return __with_key(
std::get<0>(__tuple1),
std::forward<_PiecewiseConstruct>(__pc),
std::forward<_Tuple1>(__tuple1),
std::forward<_Tuple2>(__tuple2));
}
#endif // _LIBCPP_CXX03_LANG
// This function tries extracting the given _KeyT from _Args...
// If it succeeds to extract the key, it calls the `__with_key` function with the extracted key and all of the
// arguments. Otherwise it calls the `__without_key` function with all of the arguments.
//
// Both `__with_key` and `__without_key` must take all arguments by reference.
template <class _KeyT, class _WithKey, class _WithoutKey, class... _Args>
_LIBCPP_HIDE_FROM_ABI decltype(std::declval<_WithoutKey>()(std::declval<_Args>()...))
__try_key_extraction(_WithKey __with_key, _WithoutKey __without_key, _Args&&... __args) {
using _Ret = decltype(__without_key(std::forward<_Args>(__args)...));
return std::__try_key_extraction_impl<_KeyT, _Ret>(
__priority_tag<1>(), __with_key, __without_key, std::forward<_Args>(__args)...);
}
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___UTILITY_TRY_EXTRACT_KEY_H
|
