xref: /llvm-project/libcxx/include/__cxx03/__pstl/handle_exception.h (revision ce7771902dc50d900de639d499a60486b83f70e0)
1e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===//
2e78f53d1SNikolas Klauser //
3e78f53d1SNikolas Klauser // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4e78f53d1SNikolas Klauser // See https://llvm.org/LICENSE.txt for license information.
5e78f53d1SNikolas Klauser // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6e78f53d1SNikolas Klauser //
7e78f53d1SNikolas Klauser //===----------------------------------------------------------------------===//
8e78f53d1SNikolas Klauser 
9*ce777190SNikolas Klauser #ifndef _LIBCPP___CXX03___PSTL_HANDLE_EXCEPTION_H
10*ce777190SNikolas Klauser #define _LIBCPP___CXX03___PSTL_HANDLE_EXCEPTION_H
11e78f53d1SNikolas Klauser 
1273fbae83SNikolas Klauser #include <__cxx03/__config>
1373fbae83SNikolas Klauser #include <__cxx03/__utility/forward.h>
1473fbae83SNikolas Klauser #include <__cxx03/__utility/move.h>
1573fbae83SNikolas Klauser #include <__cxx03/new> // __throw_bad_alloc
1673fbae83SNikolas Klauser #include <__cxx03/optional>
17e78f53d1SNikolas Klauser 
18e78f53d1SNikolas Klauser #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19e78f53d1SNikolas Klauser #  pragma GCC system_header
20e78f53d1SNikolas Klauser #endif
21e78f53d1SNikolas Klauser 
22e78f53d1SNikolas Klauser _LIBCPP_PUSH_MACROS
2373fbae83SNikolas Klauser #include <__cxx03/__undef_macros>
24e78f53d1SNikolas Klauser 
25e78f53d1SNikolas Klauser _LIBCPP_BEGIN_NAMESPACE_STD
26e78f53d1SNikolas Klauser namespace __pstl {
27e78f53d1SNikolas Klauser 
28e78f53d1SNikolas Klauser template <class _BackendFunction, class... _Args>
29e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI auto __handle_exception_impl(_Args&&... __args) noexcept {
30e78f53d1SNikolas Klauser   return _BackendFunction{}(std::forward<_Args>(__args)...);
31e78f53d1SNikolas Klauser }
32e78f53d1SNikolas Klauser 
33e78f53d1SNikolas Klauser // This function is used to call a backend PSTL algorithm from a frontend algorithm.
34e78f53d1SNikolas Klauser //
35e78f53d1SNikolas Klauser // All PSTL backend algorithms return an optional denoting whether there was an
36e78f53d1SNikolas Klauser // "infrastructure"-level failure (aka failure to allocate). This function takes
37e78f53d1SNikolas Klauser // care of unwrapping that and throwing `bad_alloc()` in case there was a problem
38e78f53d1SNikolas Klauser // in the underlying implementation.
39e78f53d1SNikolas Klauser //
40e78f53d1SNikolas Klauser // We must also be careful not to call any user code that could throw an exception
41e78f53d1SNikolas Klauser // (such as moving or copying iterators) in here since that should terminate the
42e78f53d1SNikolas Klauser // program, which is why we delegate to a noexcept helper below.
43e78f53d1SNikolas Klauser template <class _BackendFunction, class... _Args>
44e78f53d1SNikolas Klauser _LIBCPP_HIDE_FROM_ABI auto __handle_exception(_Args&&... __args) {
45e78f53d1SNikolas Klauser   auto __result = __pstl::__handle_exception_impl<_BackendFunction>(std::forward<_Args>(__args)...);
46e78f53d1SNikolas Klauser   if (__result == nullopt)
47e78f53d1SNikolas Klauser     std::__throw_bad_alloc();
48e78f53d1SNikolas Klauser   else
49e78f53d1SNikolas Klauser     return std::move(*__result);
50e78f53d1SNikolas Klauser }
51e78f53d1SNikolas Klauser 
52e78f53d1SNikolas Klauser } // namespace __pstl
53e78f53d1SNikolas Klauser _LIBCPP_END_NAMESPACE_STD
54e78f53d1SNikolas Klauser 
55e78f53d1SNikolas Klauser _LIBCPP_POP_MACROS
56e78f53d1SNikolas Klauser 
57*ce777190SNikolas Klauser #endif // _LIBCPP___CXX03___PSTL_HANDLE_EXCEPTION_H
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