1 /* Proposed SG14 status_code
2 (C) 2018-2020 Niall Douglas <http://www.nedproductions.biz/> (5 commits)
3 File Created: Feb 2018
4
5
6 Boost Software License - Version 1.0 - August 17th, 2003
7
8 Permission is hereby granted, free of charge, to any person or organization
9 obtaining a copy of the software and accompanying documentation covered by
10 this license (the "Software") to use, reproduce, display, distribute,
11 execute, and transmit the Software, and to prepare derivative works of the
12 Software, and to permit third-parties to whom the Software is furnished to
13 do so, all subject to the following:
14
15 The copyright notices in the Software and this entire statement, including
16 the above license grant, this restriction and the following disclaimer,
17 must be included in all copies of the Software, in whole or in part, and
18 all derivative works of the Software, unless such copies or derivative
19 works are solely in the form of machine-executable object code generated by
20 a source language processor.
21
22 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
25 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
26 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
27 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
28 DEALINGS IN THE SOFTWARE.
29 */
30
31 #ifndef BOOST_OUTCOME_SYSTEM_ERROR2_WIN32_CODE_HPP
32 #define BOOST_OUTCOME_SYSTEM_ERROR2_WIN32_CODE_HPP
33
34 #if !defined(_WIN32) && !defined(BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE)
35 #error This file should only be included on Windows
36 #endif
37
38 #include "quick_status_code_from_enum.hpp"
39
40 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_BEGIN
41
42 //! \exclude
43 namespace win32
44 {
45 // A Win32 DWORD
46 using DWORD = unsigned long;
47 // Used to retrieve the current Win32 error code
48 extern DWORD __stdcall GetLastError();
49 // Used to retrieve a locale-specific message string for some error code
50 extern DWORD __stdcall FormatMessageW(DWORD dwFlags, const void *lpSource, DWORD dwMessageId, DWORD dwLanguageId, wchar_t *lpBuffer, DWORD nSize, void /*va_list*/ *Arguments);
51 // Converts UTF-16 message string to UTF-8
52 extern int __stdcall WideCharToMultiByte(unsigned int CodePage, DWORD dwFlags, const wchar_t *lpWideCharStr, int cchWideChar, char *lpMultiByteStr, int cbMultiByte, const char *lpDefaultChar, int *lpUsedDefaultChar);
53 #pragma comment(lib, "kernel32.lib")
54 #if defined(_WIN64)
55 #pragma comment(linker, "/alternatename:?GetLastError@win32@system_error2@@YAKXZ=GetLastError")
56 #pragma comment(linker, "/alternatename:?FormatMessageW@win32@system_error2@@YAKKPEBXKKPEA_WKPEAX@Z=FormatMessageW")
57 #pragma comment(linker, "/alternatename:?WideCharToMultiByte@win32@system_error2@@YAHIKPEB_WHPEADHPEBDPEAH@Z=WideCharToMultiByte")
58 #else
59 #pragma comment(linker, "/alternatename:?GetLastError@win32@system_error2@@YGKXZ=__imp__GetLastError@0")
60 #pragma comment(linker, "/alternatename:?FormatMessageW@win32@system_error2@@YGKKPBXKKPA_WKPAX@Z=__imp__FormatMessageW@28")
61 #pragma comment(linker, "/alternatename:?WideCharToMultiByte@win32@system_error2@@YGHIKPB_WHPADHPBDPAH@Z=__imp__WideCharToMultiByte@32")
62 #endif
63 } // namespace win32
64
65 class _win32_code_domain;
66 class _com_code_domain;
67 //! (Windows only) A Win32 error code, those returned by `GetLastError()`.
68 using win32_code = status_code<_win32_code_domain>;
69 //! (Windows only) A specialisation of `status_error` for the Win32 error code domain.
70 using win32_error = status_error<_win32_code_domain>;
71
72 namespace mixins
73 {
74 template <class Base> struct mixin<Base, _win32_code_domain> : public Base
75 {
76 using Base::Base;
77
78 //! Returns a `win32_code` for the current value of `GetLastError()`.
79 static inline win32_code current() noexcept;
80 };
81 } // namespace mixins
82
83 /*! (Windows only) The implementation of the domain for Win32 error codes, those returned by `GetLastError()`.
84 */
85 class _win32_code_domain : public status_code_domain
86 {
87 template <class DomainType> friend class status_code;
88 template <class StatusCode> friend class detail::indirecting_domain;
89 friend class _com_code_domain;
90 using _base = status_code_domain;
_win32_code_to_errno(win32::DWORD c)91 static int _win32_code_to_errno(win32::DWORD c)
92 {
93 switch(c)
94 {
95 case 0:
96 return 0;
97 #include "detail/win32_code_to_generic_code.ipp"
98 }
99 return -1;
100 }
101 //! Construct from a Win32 error code
_make_string_ref(win32::DWORD c)102 static _base::string_ref _make_string_ref(win32::DWORD c) noexcept
103 {
104 wchar_t buffer[32768];
105 win32::DWORD wlen = win32::FormatMessageW(0x00001000 /*FORMAT_MESSAGE_FROM_SYSTEM*/ | 0x00000200 /*FORMAT_MESSAGE_IGNORE_INSERTS*/, nullptr, c, 0, buffer, 32768, nullptr);
106 size_t allocation = wlen + (wlen >> 1);
107 win32::DWORD bytes;
108 if(wlen == 0)
109 {
110 return _base::string_ref("failed to get message from system");
111 }
112 for(;;)
113 {
114 auto *p = static_cast<char *>(malloc(allocation)); // NOLINT
115 if(p == nullptr)
116 {
117 return _base::string_ref("failed to get message from system");
118 }
119 bytes = win32::WideCharToMultiByte(65001 /*CP_UTF8*/, 0, buffer, (int) (wlen + 1), p, (int) allocation, nullptr, nullptr);
120 if(bytes != 0)
121 {
122 char *end = strchr(p, 0);
123 while(end[-1] == 10 || end[-1] == 13)
124 {
125 --end;
126 }
127 *end = 0; // NOLINT
128 return _base::atomic_refcounted_string_ref(p, end - p);
129 }
130 free(p); // NOLINT
131 if(win32::GetLastError() == 0x7a /*ERROR_INSUFFICIENT_BUFFER*/)
132 {
133 allocation += allocation >> 2;
134 continue;
135 }
136 return _base::string_ref("failed to get message from system");
137 }
138 }
139
140 public:
141 //! The value type of the win32 code, which is a `win32::DWORD`
142 using value_type = win32::DWORD;
143 using _base::string_ref;
144
145 public:
146 //! Default constructor
_win32_code_domain(typename _base::unique_id_type id=0x8cd18ee72d680f1b)147 constexpr explicit _win32_code_domain(typename _base::unique_id_type id = 0x8cd18ee72d680f1b) noexcept
148 : _base(id)
149 {
150 }
151 _win32_code_domain(const _win32_code_domain &) = default;
152 _win32_code_domain(_win32_code_domain &&) = default;
153 _win32_code_domain &operator=(const _win32_code_domain &) = default;
154 _win32_code_domain &operator=(_win32_code_domain &&) = default;
155 ~_win32_code_domain() = default;
156
157 //! Constexpr singleton getter. Returns the constexpr win32_code_domain variable.
158 static inline constexpr const _win32_code_domain &get();
159
name() const160 virtual string_ref name() const noexcept override { return string_ref("win32 domain"); } // NOLINT
161 protected:
_do_failure(const status_code<void> & code) const162 virtual bool _do_failure(const status_code<void> &code) const noexcept override // NOLINT
163 {
164 assert(code.domain() == *this);
165 return static_cast<const win32_code &>(code).value() != 0; // NOLINT
166 }
_do_equivalent(const status_code<void> & code1,const status_code<void> & code2) const167 virtual bool _do_equivalent(const status_code<void> &code1, const status_code<void> &code2) const noexcept override // NOLINT
168 {
169 assert(code1.domain() == *this);
170 const auto &c1 = static_cast<const win32_code &>(code1); // NOLINT
171 if(code2.domain() == *this)
172 {
173 const auto &c2 = static_cast<const win32_code &>(code2); // NOLINT
174 return c1.value() == c2.value();
175 }
176 if(code2.domain() == generic_code_domain)
177 {
178 const auto &c2 = static_cast<const generic_code &>(code2); // NOLINT
179 if(static_cast<int>(c2.value()) == _win32_code_to_errno(c1.value()))
180 {
181 return true;
182 }
183 }
184 return false;
185 }
_generic_code(const status_code<void> & code) const186 virtual generic_code _generic_code(const status_code<void> &code) const noexcept override // NOLINT
187 {
188 assert(code.domain() == *this);
189 const auto &c = static_cast<const win32_code &>(code); // NOLINT
190 return generic_code(static_cast<errc>(_win32_code_to_errno(c.value())));
191 }
_do_message(const status_code<void> & code) const192 virtual string_ref _do_message(const status_code<void> &code) const noexcept override // NOLINT
193 {
194 assert(code.domain() == *this);
195 const auto &c = static_cast<const win32_code &>(code); // NOLINT
196 return _make_string_ref(c.value());
197 }
198 #if defined(_CPPUNWIND) || defined(__EXCEPTIONS) || defined(BOOST_OUTCOME_STANDARDESE_IS_IN_THE_HOUSE)
_do_throw_exception(const status_code<void> & code) const199 BOOST_OUTCOME_SYSTEM_ERROR2_NORETURN virtual void _do_throw_exception(const status_code<void> &code) const override // NOLINT
200 {
201 assert(code.domain() == *this);
202 const auto &c = static_cast<const win32_code &>(code); // NOLINT
203 throw status_error<_win32_code_domain>(c);
204 }
205 #endif
206 };
207 //! (Windows only) A constexpr source variable for the win32 code domain, which is that of `GetLastError()` (Windows). Returned by `_win32_code_domain::get()`.
208 constexpr _win32_code_domain win32_code_domain;
get()209 inline constexpr const _win32_code_domain &_win32_code_domain::get()
210 {
211 return win32_code_domain;
212 }
213
214 namespace mixins
215 {
current()216 template <class Base> inline win32_code mixin<Base, _win32_code_domain>::current() noexcept { return win32_code(win32::GetLastError()); }
217 } // namespace mixins
218
219 BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE_END
220
221 #endif
222