xref: /freebsd-src/contrib/llvm-project/libcxx/include/__pstl/handle_exception.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1*0fca6ea1SDimitry Andric //===----------------------------------------------------------------------===//
2*0fca6ea1SDimitry Andric //
3*0fca6ea1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*0fca6ea1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5*0fca6ea1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*0fca6ea1SDimitry Andric //
7*0fca6ea1SDimitry Andric //===----------------------------------------------------------------------===//
8*0fca6ea1SDimitry Andric 
9*0fca6ea1SDimitry Andric #ifndef _LIBCPP___PSTL_HANDLE_EXCEPTION_H
10*0fca6ea1SDimitry Andric #define _LIBCPP___PSTL_HANDLE_EXCEPTION_H
11*0fca6ea1SDimitry Andric 
12*0fca6ea1SDimitry Andric #include <__config>
13*0fca6ea1SDimitry Andric #include <__utility/forward.h>
14*0fca6ea1SDimitry Andric #include <__utility/move.h>
15*0fca6ea1SDimitry Andric #include <new> // __throw_bad_alloc
16*0fca6ea1SDimitry Andric #include <optional>
17*0fca6ea1SDimitry Andric 
18*0fca6ea1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19*0fca6ea1SDimitry Andric #  pragma GCC system_header
20*0fca6ea1SDimitry Andric #endif
21*0fca6ea1SDimitry Andric 
22*0fca6ea1SDimitry Andric _LIBCPP_PUSH_MACROS
23*0fca6ea1SDimitry Andric #include <__undef_macros>
24*0fca6ea1SDimitry Andric 
25*0fca6ea1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
26*0fca6ea1SDimitry Andric namespace __pstl {
27*0fca6ea1SDimitry Andric 
28*0fca6ea1SDimitry Andric template <class _BackendFunction, class... _Args>
29*0fca6ea1SDimitry Andric _LIBCPP_HIDE_FROM_ABI auto __handle_exception_impl(_Args&&... __args) noexcept {
30*0fca6ea1SDimitry Andric   return _BackendFunction{}(std::forward<_Args>(__args)...);
31*0fca6ea1SDimitry Andric }
32*0fca6ea1SDimitry Andric 
33*0fca6ea1SDimitry Andric // This function is used to call a backend PSTL algorithm from a frontend algorithm.
34*0fca6ea1SDimitry Andric //
35*0fca6ea1SDimitry Andric // All PSTL backend algorithms return an optional denoting whether there was an
36*0fca6ea1SDimitry Andric // "infrastructure"-level failure (aka failure to allocate). This function takes
37*0fca6ea1SDimitry Andric // care of unwrapping that and throwing `bad_alloc()` in case there was a problem
38*0fca6ea1SDimitry Andric // in the underlying implementation.
39*0fca6ea1SDimitry Andric //
40*0fca6ea1SDimitry Andric // We must also be careful not to call any user code that could throw an exception
41*0fca6ea1SDimitry Andric // (such as moving or copying iterators) in here since that should terminate the
42*0fca6ea1SDimitry Andric // program, which is why we delegate to a noexcept helper below.
43*0fca6ea1SDimitry Andric template <class _BackendFunction, class... _Args>
44*0fca6ea1SDimitry Andric _LIBCPP_HIDE_FROM_ABI auto __handle_exception(_Args&&... __args) {
45*0fca6ea1SDimitry Andric   auto __result = __pstl::__handle_exception_impl<_BackendFunction>(std::forward<_Args>(__args)...);
46*0fca6ea1SDimitry Andric   if (__result == nullopt)
47*0fca6ea1SDimitry Andric     std::__throw_bad_alloc();
48*0fca6ea1SDimitry Andric   else
49*0fca6ea1SDimitry Andric     return std::move(*__result);
50*0fca6ea1SDimitry Andric }
51*0fca6ea1SDimitry Andric 
52*0fca6ea1SDimitry Andric } // namespace __pstl
53*0fca6ea1SDimitry Andric _LIBCPP_END_NAMESPACE_STD
54*0fca6ea1SDimitry Andric 
55*0fca6ea1SDimitry Andric _LIBCPP_POP_MACROS
56*0fca6ea1SDimitry Andric 
57*0fca6ea1SDimitry Andric #endif // _LIBCPP___PSTL_HANDLE_EXCEPTION_H
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