1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___PSTL_HANDLE_EXCEPTION_H 10 #define _LIBCPP___PSTL_HANDLE_EXCEPTION_H 11 12 #include <__config> 13 #include <__new/exceptions.h> 14 #include <__utility/forward.h> 15 #include <__utility/move.h> 16 #include <optional> 17 18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19 # pragma GCC system_header 20 #endif 21 22 _LIBCPP_PUSH_MACROS 23 #include <__undef_macros> 24 25 #if _LIBCPP_STD_VER >= 17 26 27 _LIBCPP_BEGIN_NAMESPACE_STD 28 namespace __pstl { 29 30 template <class _BackendFunction, class... _Args> 31 _LIBCPP_HIDE_FROM_ABI auto __handle_exception_impl(_Args&&... __args) noexcept { 32 return _BackendFunction{}(std::forward<_Args>(__args)...); 33 } 34 35 // This function is used to call a backend PSTL algorithm from a frontend algorithm. 36 // 37 // All PSTL backend algorithms return an optional denoting whether there was an 38 // "infrastructure"-level failure (aka failure to allocate). This function takes 39 // care of unwrapping that and throwing `bad_alloc()` in case there was a problem 40 // in the underlying implementation. 41 // 42 // We must also be careful not to call any user code that could throw an exception 43 // (such as moving or copying iterators) in here since that should terminate the 44 // program, which is why we delegate to a noexcept helper below. 45 template <class _BackendFunction, class... _Args> 46 _LIBCPP_HIDE_FROM_ABI auto __handle_exception(_Args&&... __args) { 47 auto __result = __pstl::__handle_exception_impl<_BackendFunction>(std::forward<_Args>(__args)...); 48 if (__result == nullopt) 49 std::__throw_bad_alloc(); 50 else 51 return std::move(*__result); 52 } 53 54 } // namespace __pstl 55 _LIBCPP_END_NAMESPACE_STD 56 57 #endif // _LIBCPP_STD_VER >= 17 58 59 _LIBCPP_POP_MACROS 60 61 #endif // _LIBCPP___PSTL_HANDLE_EXCEPTION_H 62