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___EXCEPTION_EXCEPTION_H
10#define _LIBCPP___EXCEPTION_EXCEPTION_H
11
12#include <__config>
13
14// <vcruntime_exception.h> defines its own std::exception and std::bad_exception types,
15// which we use in order to be ABI-compatible with other STLs on Windows.
16#if defined(_LIBCPP_ABI_VCRUNTIME)
17#  include <vcruntime_exception.h>
18#endif
19
20#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21#  pragma GCC system_header
22#endif
23
24_LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD
25
26#if defined(_LIBCPP_ABI_VCRUNTIME) && (!defined(_HAS_EXCEPTIONS) || _HAS_EXCEPTIONS != 0)
27// The std::exception class was already included above, but we're explicit about this condition here for clarity.
28
29#elif defined(_LIBCPP_ABI_VCRUNTIME) && _HAS_EXCEPTIONS == 0
30// However, <vcruntime_exception.h> does not define std::exception and std::bad_exception
31// when _HAS_EXCEPTIONS == 0.
32//
33// Since libc++ still wants to provide the std::exception hierarchy even when _HAS_EXCEPTIONS == 0
34// (after all those are simply types like any other), we define an ABI-compatible version
35// of the VCRuntime std::exception and std::bad_exception types in that mode.
36
37struct __std_exception_data {
38  char const* _What;
39  bool _DoFree;
40};
41
42class exception { // base of all library exceptions
43public:
44  exception() _NOEXCEPT : __data_() {}
45
46  explicit exception(char const* __message) _NOEXCEPT : __data_() {
47    __data_._What   = __message;
48    __data_._DoFree = true;
49  }
50
51  exception(exception const&) _NOEXCEPT {}
52
53  exception& operator=(exception const&) _NOEXCEPT { return *this; }
54
55  virtual ~exception() _NOEXCEPT {}
56
57  virtual char const* what() const _NOEXCEPT { return __data_._What ? __data_._What : "Unknown exception"; }
58
59private:
60  __std_exception_data __data_;
61};
62
63class bad_exception : public exception {
64public:
65  bad_exception() _NOEXCEPT : exception("bad exception") {}
66};
67
68#else  // !defined(_LIBCPP_ABI_VCRUNTIME)
69// On all other platforms, we define our own std::exception and std::bad_exception types
70// regardless of whether exceptions are turned on as a language feature.
71
72class _LIBCPP_EXPORTED_FROM_ABI exception {
73public:
74  _LIBCPP_HIDE_FROM_ABI exception() _NOEXCEPT {}
75  _LIBCPP_HIDE_FROM_ABI exception(const exception&) _NOEXCEPT            = default;
76  _LIBCPP_HIDE_FROM_ABI exception& operator=(const exception&) _NOEXCEPT = default;
77
78  virtual ~exception() _NOEXCEPT;
79  virtual const char* what() const _NOEXCEPT;
80};
81
82class _LIBCPP_EXPORTED_FROM_ABI bad_exception : public exception {
83public:
84  _LIBCPP_HIDE_FROM_ABI bad_exception() _NOEXCEPT {}
85  _LIBCPP_HIDE_FROM_ABI bad_exception(const bad_exception&) _NOEXCEPT            = default;
86  _LIBCPP_HIDE_FROM_ABI bad_exception& operator=(const bad_exception&) _NOEXCEPT = default;
87  ~bad_exception() _NOEXCEPT override;
88  const char* what() const _NOEXCEPT override;
89};
90#endif // !_LIBCPP_ABI_VCRUNTIME
91
92_LIBCPP_END_UNVERSIONED_NAMESPACE_STD
93
94#endif // _LIBCPP___EXCEPTION_EXCEPTION_H