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1 // Formatting library for C++ - optional OS-specific functionality
2 //
3 // Copyright (c) 2012 - present, Victor Zverovich
4 // All rights reserved.
5 //
6 // For the license information refer to format.h.
7 
8 #ifndef FMT_OS_H_
9 #define FMT_OS_H_
10 
11 #if defined(__MINGW32__) || defined(__CYGWIN__)
12 // Workaround MinGW bug https://sourceforge.net/p/mingw/bugs/2024/.
13 #  undef __STRICT_ANSI__
14 #endif
15 
16 #include <cerrno>
17 #include <clocale>  // for locale_t
18 #include <cstddef>
19 #include <cstdio>
20 #include <cstdlib>  // for strtod_l
21 
22 #if defined __APPLE__ || defined(__FreeBSD__)
23 #  include <xlocale.h>  // for LC_NUMERIC_MASK on OS X
24 #endif
25 
26 #include "format.h"
27 
28 // UWP doesn't provide _pipe.
29 #if FMT_HAS_INCLUDE("winapifamily.h")
30 #  include <winapifamily.h>
31 #endif
32 #if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
33      defined(__linux__)) &&                              \
34     (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
35 #  include <fcntl.h>  // for O_RDONLY
36 #  define FMT_USE_FCNTL 1
37 #else
38 #  define FMT_USE_FCNTL 0
39 #endif
40 
41 #ifndef FMT_POSIX
42 #  if defined(_WIN32) && !defined(__MINGW32__)
43 // Fix warnings about deprecated symbols.
44 #    define FMT_POSIX(call) _##call
45 #  else
46 #    define FMT_POSIX(call) call
47 #  endif
48 #endif
49 
50 // Calls to system functions are wrapped in FMT_SYSTEM for testability.
51 #ifdef FMT_SYSTEM
52 #  define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
53 #else
54 #  define FMT_SYSTEM(call) ::call
55 #  ifdef _WIN32
56 // Fix warnings about deprecated symbols.
57 #    define FMT_POSIX_CALL(call) ::_##call
58 #  else
59 #    define FMT_POSIX_CALL(call) ::call
60 #  endif
61 #endif
62 
63 // Retries the expression while it evaluates to error_result and errno
64 // equals to EINTR.
65 #ifndef _WIN32
66 #  define FMT_RETRY_VAL(result, expression, error_result) \
67     do {                                                  \
68       (result) = (expression);                            \
69     } while ((result) == (error_result) && errno == EINTR)
70 #else
71 #  define FMT_RETRY_VAL(result, expression, error_result) result = (expression)
72 #endif
73 
74 #define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
75 
76 FMT_BEGIN_NAMESPACE
77 
78 /**
79   \rst
80   A reference to a null-terminated string. It can be constructed from a C
81   string or ``std::string``.
82 
83   You can use one of the following type aliases for common character types:
84 
85   +---------------+-----------------------------+
86   | Type          | Definition                  |
87   +===============+=============================+
88   | cstring_view  | basic_cstring_view<char>    |
89   +---------------+-----------------------------+
90   | wcstring_view | basic_cstring_view<wchar_t> |
91   +---------------+-----------------------------+
92 
93   This class is most useful as a parameter type to allow passing
94   different types of strings to a function, for example::
95 
96     template <typename... Args>
97     std::string format(cstring_view format_str, const Args & ... args);
98 
99     format("{}", 42);
100     format(std::string("{}"), 42);
101   \endrst
102  */
103 template <typename Char> class basic_cstring_view {
104  private:
105   const Char* data_;
106 
107  public:
108   /** Constructs a string reference object from a C string. */
basic_cstring_view(const Char * s)109   basic_cstring_view(const Char* s) : data_(s) {}
110 
111   /**
112     \rst
113     Constructs a string reference from an ``std::string`` object.
114     \endrst
115    */
basic_cstring_view(const std::basic_string<Char> & s)116   basic_cstring_view(const std::basic_string<Char>& s) : data_(s.c_str()) {}
117 
118   /** Returns the pointer to a C string. */
c_str()119   const Char* c_str() const { return data_; }
120 };
121 
122 using cstring_view = basic_cstring_view<char>;
123 using wcstring_view = basic_cstring_view<wchar_t>;
124 
125 // An error code.
126 class error_code {
127  private:
128   int value_;
129 
130  public:
value_(value)131   explicit error_code(int value = 0) FMT_NOEXCEPT : value_(value) {}
132 
get()133   int get() const FMT_NOEXCEPT { return value_; }
134 };
135 
136 #ifdef _WIN32
137 namespace detail {
138 // A converter from UTF-16 to UTF-8.
139 // It is only provided for Windows since other systems support UTF-8 natively.
140 class utf16_to_utf8 {
141  private:
142   memory_buffer buffer_;
143 
144  public:
utf16_to_utf8()145   utf16_to_utf8() {}
146   FMT_API explicit utf16_to_utf8(wstring_view s);
string_view()147   operator string_view() const { return string_view(&buffer_[0], size()); }
size()148   size_t size() const { return buffer_.size() - 1; }
c_str()149   const char* c_str() const { return &buffer_[0]; }
str()150   std::string str() const { return std::string(&buffer_[0], size()); }
151 
152   // Performs conversion returning a system error code instead of
153   // throwing exception on conversion error. This method may still throw
154   // in case of memory allocation error.
155   FMT_API int convert(wstring_view s);
156 };
157 
158 FMT_API void format_windows_error(buffer<char>& out, int error_code,
159                                   string_view message) FMT_NOEXCEPT;
160 }  // namespace detail
161 
162 /** A Windows error. */
163 class windows_error : public system_error {
164  private:
165   FMT_API void init(int error_code, string_view format_str, format_args args);
166 
167  public:
168   /**
169    \rst
170    Constructs a :class:`fmt::windows_error` object with the description
171    of the form
172 
173    .. parsed-literal::
174      *<message>*: *<system-message>*
175 
176    where *<message>* is the formatted message and *<system-message>* is the
177    system message corresponding to the error code.
178    *error_code* is a Windows error code as given by ``GetLastError``.
179    If *error_code* is not a valid error code such as -1, the system message
180    will look like "error -1".
181 
182    **Example**::
183 
184      // This throws a windows_error with the description
185      //   cannot open file 'madeup': The system cannot find the file specified.
186      // or similar (system message may vary).
187      const char *filename = "madeup";
188      LPOFSTRUCT of = LPOFSTRUCT();
189      HFILE file = OpenFile(filename, &of, OF_READ);
190      if (file == HFILE_ERROR) {
191        throw fmt::windows_error(GetLastError(),
192                                 "cannot open file '{}'", filename);
193      }
194    \endrst
195   */
196   template <typename... Args>
windows_error(int error_code,string_view message,const Args &...args)197   windows_error(int error_code, string_view message, const Args&... args) {
198     init(error_code, message, make_format_args(args...));
199   }
200 };
201 
202 // Reports a Windows error without throwing an exception.
203 // Can be used to report errors from destructors.
204 FMT_API void report_windows_error(int error_code,
205                                   string_view message) FMT_NOEXCEPT;
206 #endif  // _WIN32
207 
208 // A buffered file.
209 class buffered_file {
210  private:
211   FILE* file_;
212 
213   friend class file;
214 
buffered_file(FILE * f)215   explicit buffered_file(FILE* f) : file_(f) {}
216 
217  public:
218   buffered_file(const buffered_file&) = delete;
219   void operator=(const buffered_file&) = delete;
220 
221   // Constructs a buffered_file object which doesn't represent any file.
buffered_file()222   buffered_file() FMT_NOEXCEPT : file_(nullptr) {}
223 
224   // Destroys the object closing the file it represents if any.
225   FMT_API ~buffered_file() FMT_NOEXCEPT;
226 
227  public:
buffered_file(buffered_file && other)228   buffered_file(buffered_file&& other) FMT_NOEXCEPT : file_(other.file_) {
229     other.file_ = nullptr;
230   }
231 
232   buffered_file& operator=(buffered_file&& other) {
233     close();
234     file_ = other.file_;
235     other.file_ = nullptr;
236     return *this;
237   }
238 
239   // Opens a file.
240   FMT_API buffered_file(cstring_view filename, cstring_view mode);
241 
242   // Closes the file.
243   FMT_API void close();
244 
245   // Returns the pointer to a FILE object representing this file.
get()246   FILE* get() const FMT_NOEXCEPT { return file_; }
247 
248   // We place parentheses around fileno to workaround a bug in some versions
249   // of MinGW that define fileno as a macro.
250   FMT_API int(fileno)() const;
251 
vprint(string_view format_str,format_args args)252   void vprint(string_view format_str, format_args args) {
253     fmt::vprint(file_, format_str, args);
254   }
255 
256   template <typename... Args>
print(string_view format_str,const Args &...args)257   inline void print(string_view format_str, const Args&... args) {
258     vprint(format_str, make_format_args(args...));
259   }
260 };
261 
262 #if FMT_USE_FCNTL
263 // A file. Closed file is represented by a file object with descriptor -1.
264 // Methods that are not declared with FMT_NOEXCEPT may throw
265 // fmt::system_error in case of failure. Note that some errors such as
266 // closing the file multiple times will cause a crash on Windows rather
267 // than an exception. You can get standard behavior by overriding the
268 // invalid parameter handler with _set_invalid_parameter_handler.
269 class file {
270  private:
271   int fd_;  // File descriptor.
272 
273   // Constructs a file object with a given descriptor.
file(int fd)274   explicit file(int fd) : fd_(fd) {}
275 
276  public:
277   // Possible values for the oflag argument to the constructor.
278   enum {
279     RDONLY = FMT_POSIX(O_RDONLY),  // Open for reading only.
280     WRONLY = FMT_POSIX(O_WRONLY),  // Open for writing only.
281     RDWR = FMT_POSIX(O_RDWR),      // Open for reading and writing.
282     CREATE = FMT_POSIX(O_CREAT),   // Create if the file doesn't exist.
283     APPEND = FMT_POSIX(O_APPEND)   // Open in append mode.
284   };
285 
286   // Constructs a file object which doesn't represent any file.
file()287   file() FMT_NOEXCEPT : fd_(-1) {}
288 
289   // Opens a file and constructs a file object representing this file.
290   FMT_API file(cstring_view path, int oflag);
291 
292  public:
293   file(const file&) = delete;
294   void operator=(const file&) = delete;
295 
file(file && other)296   file(file&& other) FMT_NOEXCEPT : fd_(other.fd_) { other.fd_ = -1; }
297 
298   file& operator=(file&& other) FMT_NOEXCEPT {
299     close();
300     fd_ = other.fd_;
301     other.fd_ = -1;
302     return *this;
303   }
304 
305   // Destroys the object closing the file it represents if any.
306   FMT_API ~file() FMT_NOEXCEPT;
307 
308   // Returns the file descriptor.
descriptor()309   int descriptor() const FMT_NOEXCEPT { return fd_; }
310 
311   // Closes the file.
312   FMT_API void close();
313 
314   // Returns the file size. The size has signed type for consistency with
315   // stat::st_size.
316   FMT_API long long size() const;
317 
318   // Attempts to read count bytes from the file into the specified buffer.
319   FMT_API size_t read(void* buffer, size_t count);
320 
321   // Attempts to write count bytes from the specified buffer to the file.
322   FMT_API size_t write(const void* buffer, size_t count);
323 
324   // Duplicates a file descriptor with the dup function and returns
325   // the duplicate as a file object.
326   FMT_API static file dup(int fd);
327 
328   // Makes fd be the copy of this file descriptor, closing fd first if
329   // necessary.
330   FMT_API void dup2(int fd);
331 
332   // Makes fd be the copy of this file descriptor, closing fd first if
333   // necessary.
334   FMT_API void dup2(int fd, error_code& ec) FMT_NOEXCEPT;
335 
336   // Creates a pipe setting up read_end and write_end file objects for reading
337   // and writing respectively.
338   FMT_API static void pipe(file& read_end, file& write_end);
339 
340   // Creates a buffered_file object associated with this file and detaches
341   // this file object from the file.
342   FMT_API buffered_file fdopen(const char* mode);
343 };
344 
345 // Returns the memory page size.
346 long getpagesize();
347 
348 namespace detail {
349 
350 struct buffer_size {
351   size_t value = 0;
352   buffer_size operator=(size_t val) const {
353     auto bs = buffer_size();
354     bs.value = val;
355     return bs;
356   }
357 };
358 
359 struct ostream_params {
360   int oflag = file::WRONLY | file::CREATE;
361   size_t buffer_size = BUFSIZ > 32768 ? BUFSIZ : 32768;
362 
ostream_paramsostream_params363   ostream_params() {}
364 
365   template <typename... T>
ostream_paramsostream_params366   ostream_params(T... params, int oflag) : ostream_params(params...) {
367     this->oflag = oflag;
368   }
369 
370   template <typename... T>
ostream_paramsostream_params371   ostream_params(T... params, detail::buffer_size bs)
372       : ostream_params(params...) {
373     this->buffer_size = bs.value;
374   }
375 };
376 }  // namespace detail
377 
378 static constexpr detail::buffer_size buffer_size;
379 
380 // A fast output stream which is not thread-safe.
381 class ostream final : private detail::buffer<char> {
382  private:
383   file file_;
384 
flush()385   void flush() {
386     if (size() == 0) return;
387     file_.write(data(), size());
388     clear();
389   }
390 
grow(size_t)391   FMT_API void grow(size_t) override final;
392 
393   ostream(cstring_view path, const detail::ostream_params& params)
394       : file_(path, params.oflag) {
395     set(new char[params.buffer_size], params.buffer_size);
396   }
397 
398  public:
ostream(ostream && other)399   ostream(ostream&& other)
400       : detail::buffer<char>(other.data(), other.size(), other.capacity()),
401         file_(std::move(other.file_)) {
402     other.set(nullptr, 0);
403   }
~ostream()404   ~ostream() {
405     flush();
406     delete[] data();
407   }
408 
409   template <typename... T>
410   friend ostream output_file(cstring_view path, T... params);
411 
close()412   void close() {
413     flush();
414     file_.close();
415   }
416 
417   template <typename S, typename... Args>
print(const S & format_str,const Args &...args)418   void print(const S& format_str, const Args&... args) {
419     format_to(detail::buffer_appender<char>(*this), format_str, args...);
420   }
421 };
422 
423 /**
424   Opens a file for writing. Supported parameters passed in `params`:
425   * ``<integer>``: Output flags (``file::WRONLY | file::CREATE`` by default)
426   * ``buffer_size=<integer>``: Output buffer size
427  */
428 template <typename... T>
output_file(cstring_view path,T...params)429 inline ostream output_file(cstring_view path, T... params) {
430   return {path, detail::ostream_params(params...)};
431 }
432 #endif  // FMT_USE_FCNTL
433 
434 #ifdef FMT_LOCALE
435 // A "C" numeric locale.
436 class locale {
437  private:
438 #  ifdef _WIN32
439   using locale_t = _locale_t;
440 
freelocale(locale_t loc)441   static void freelocale(locale_t loc) { _free_locale(loc); }
442 
strtod_l(const char * nptr,char ** endptr,_locale_t loc)443   static double strtod_l(const char* nptr, char** endptr, _locale_t loc) {
444     return _strtod_l(nptr, endptr, loc);
445   }
446 #  endif
447 
448   locale_t locale_;
449 
450  public:
451   using type = locale_t;
452   locale(const locale&) = delete;
453   void operator=(const locale&) = delete;
454 
locale()455   locale() {
456 #  ifndef _WIN32
457     locale_ = FMT_SYSTEM(newlocale(LC_NUMERIC_MASK, "C", nullptr));
458 #  else
459     locale_ = _create_locale(LC_NUMERIC, "C");
460 #  endif
461     if (!locale_) FMT_THROW(system_error(errno, "cannot create locale"));
462   }
~locale()463   ~locale() { freelocale(locale_); }
464 
get()465   type get() const { return locale_; }
466 
467   // Converts string to floating-point number and advances str past the end
468   // of the parsed input.
strtod(const char * & str)469   double strtod(const char*& str) const {
470     char* end = nullptr;
471     double result = strtod_l(str, &end, locale_);
472     str = end;
473     return result;
474   }
475 };
476 using Locale FMT_DEPRECATED_ALIAS = locale;
477 #endif  // FMT_LOCALE
478 FMT_END_NAMESPACE
479 
480 #endif  // FMT_OS_H_
481