xref: /netbsd-src/external/gpl3/gcc/dist/libstdc++-v3/include/bits/fs_path.h (revision c42dbd0ed2e61fe6eda8590caa852ccf34719964)
1 // Class filesystem::path -*- C++ -*-
2 
3 // Copyright (C) 2014-2022 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library.  This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file include/bits/fs_path.h
26  *  This is an internal header file, included by other library headers.
27  *  Do not attempt to use it directly. @headername{filesystem}
28  */
29 
30 #ifndef _GLIBCXX_FS_PATH_H
31 #define _GLIBCXX_FS_PATH_H 1
32 
33 #if __cplusplus >= 201703L
34 
35 #include <type_traits>
36 #include <locale>
37 #include <iosfwd>
38 #include <iomanip>
39 #include <codecvt>
40 #include <string_view>
41 #include <system_error>
42 #include <bits/stl_algobase.h>
43 #include <bits/stl_pair.h>
44 #include <bits/locale_conv.h>
45 #include <ext/concurrence.h>
46 #include <bits/shared_ptr.h>
47 #include <bits/unique_ptr.h>
48 
49 #if __cplusplus > 201703L
50 # include <compare>
51 #endif
52 
53 #if defined(_WIN32) && !defined(__CYGWIN__)
54 # define _GLIBCXX_FILESYSTEM_IS_WINDOWS 1
55 #endif
56 
57 namespace std _GLIBCXX_VISIBILITY(default)
58 {
59 _GLIBCXX_BEGIN_NAMESPACE_VERSION
60 
61 namespace filesystem
62 {
63 _GLIBCXX_BEGIN_NAMESPACE_CXX11
64 
65   class path;
66 
67   /// @cond undocumented
68 namespace __detail
69 {
70   /// @addtogroup filesystem
71   /// @{
72   template<typename _CharT>
73     inline constexpr bool __is_encoded_char = false;
74   template<>
75     inline constexpr bool __is_encoded_char<char> = true;
76 #ifdef _GLIBCXX_USE_CHAR8_T
77   template<>
78     inline constexpr bool __is_encoded_char<char8_t> = true;
79 #endif
80 #if _GLIBCXX_USE_WCHAR_T
81   template<>
82     inline constexpr bool __is_encoded_char<wchar_t> = true;
83 #endif
84   template<>
85     inline constexpr bool __is_encoded_char<char16_t> = true;
86   template<>
87     inline constexpr bool __is_encoded_char<char32_t> = true;
88 
89 #if __cpp_concepts >= 201907L
90   template<typename _Iter>
91     using __safe_iterator_traits = std::iterator_traits<_Iter>;
92 #else
93   template<typename _Iter>
94     struct __safe_iterator_traits : std::iterator_traits<_Iter>
95     { };
96 
97   // Protect against ill-formed iterator_traits specializations in C++17
98   template<> struct __safe_iterator_traits<void*> { };
99   template<> struct __safe_iterator_traits<const void*> { };
100   template<> struct __safe_iterator_traits<volatile void*> { };
101   template<> struct __safe_iterator_traits<const volatile void*> { };
102 #endif
103 
104   template<typename _Iter_traits, typename = void>
105     struct __is_path_iter_src
106     : false_type
107     { };
108 
109   template<typename _Iter_traits>
110     struct __is_path_iter_src<_Iter_traits,
111 			      void_t<typename _Iter_traits::value_type>>
112     : bool_constant<__is_encoded_char<typename _Iter_traits::value_type>>
113     { };
114 
115   template<typename _Source>
116     inline constexpr bool __is_path_src
117       = __is_path_iter_src<iterator_traits<decay_t<_Source>>>::value;
118 
119   template<>
120     inline constexpr bool __is_path_src<path> = false;
121 
122   template<>
123     inline constexpr bool __is_path_src<volatile path> = false;
124 
125   template<>
126     inline constexpr bool __is_path_src<void*> = false;
127 
128   template<>
129     inline constexpr bool __is_path_src<const void*> = false;
130 
131   template<>
132     inline constexpr bool __is_path_src<volatile void*> = false;
133 
134   template<>
135     inline constexpr bool __is_path_src<const volatile void*> = false;
136 
137   template<typename _CharT, typename _Traits, typename _Alloc>
138     inline constexpr bool
139       __is_path_src<basic_string<_CharT, _Traits, _Alloc>>
140 	= __is_encoded_char<_CharT>;
141 
142   template<typename _CharT, typename _Traits>
143     inline constexpr bool
144       __is_path_src<basic_string_view<_CharT, _Traits>>
145 	= __is_encoded_char<_CharT>;
146 
147   // SFINAE constraint for Source parameters as required by [fs.path.req].
148   template<typename _Tp>
149     using _Path = enable_if_t<__is_path_src<_Tp>, path>;
150 
151   // SFINAE constraint for InputIterator parameters as required by [fs.req].
152   template<typename _Iter, typename _Tr = __safe_iterator_traits<_Iter>>
153     using _Path2 = enable_if_t<__is_path_iter_src<_Tr>::value, path>;
154 
155 #if __cpp_lib_concepts
156   template<typename _Iter>
157     constexpr bool __is_contiguous = std::contiguous_iterator<_Iter>;
158 #else
159   template<typename _Iter>
160     constexpr bool __is_contiguous = false;
161 #endif
162 
163   template<typename _Tp>
164     constexpr bool __is_contiguous<_Tp*> = true;
165 
166   template<typename _Tp, typename _Seq>
167     constexpr bool
168     __is_contiguous<__gnu_cxx::__normal_iterator<_Tp*, _Seq>> = true;
169 
170 #if !defined _GLIBCXX_FILESYSTEM_IS_WINDOWS && defined _GLIBCXX_USE_CHAR8_T
171   // For POSIX treat char8_t sequences as char without encoding conversions.
172   template<typename _EcharT>
173     using __unified_u8_t
174       = __conditional_t<is_same_v<_EcharT, char8_t>, char, _EcharT>;
175 #else
176   template<typename _EcharT>
177     using __unified_u8_t = _EcharT;
178 #endif
179 
180   // The __effective_range overloads convert a Source parameter into
181   // either a basic_string_view<C> or basic_string<C> containing the
182   // effective range of the Source, as defined in [fs.path.req].
183 
184   template<typename _CharT, typename _Traits, typename _Alloc>
185     inline basic_string_view<_CharT>
186     __effective_range(const basic_string<_CharT, _Traits, _Alloc>& __source)
187     noexcept
188     { return __source; }
189 
190   template<typename _CharT, typename _Traits>
191     inline basic_string_view<_CharT>
192     __effective_range(const basic_string_view<_CharT, _Traits>& __source)
193     noexcept
194     { return __source; }
195 
196   // Return the effective range of an NTCTS.
197   template<typename _Source>
198     auto
199     __effective_range(const _Source& __source)
200     {
201       // Remove a level of normal/safe iterator indirection, or decay an array.
202       using _Iter = decltype(std::__niter_base(__source));
203       using value_type = typename iterator_traits<_Iter>::value_type;
204 
205       if constexpr (__is_contiguous<_Iter>)
206 	return basic_string_view<value_type>{&*__source};
207       else
208 	{
209 	  // _Source is an input iterator that iterates over an NTCTS.
210 	  // Create a basic_string by reading until the null character.
211 	  basic_string<__unified_u8_t<value_type>> __str;
212 	  _Source __it = __source;
213 	  for (value_type __ch = *__it; __ch != value_type(); __ch = *++__it)
214 	    __str.push_back(__ch);
215 	  return __str;
216 	}
217     }
218 
219   // The value type of a Source parameter's effective range.
220   template<typename _Source>
221     struct __source_value_type_impl
222     {
223       using type
224 	= typename __safe_iterator_traits<decay_t<_Source>>::value_type;
225     };
226 
227   template<typename _CharT, typename _Traits, typename _Alloc>
228     struct __source_value_type_impl<basic_string<_CharT, _Traits, _Alloc>>
229     {
230       using type = _CharT;
231     };
232 
233   template<typename _CharT, typename _Traits>
234     struct __source_value_type_impl<basic_string_view<_CharT, _Traits>>
235     {
236       using type = _CharT;
237     };
238 
239   // The value type of a Source parameter's effective range.
240   template<typename _Source>
241     using __source_value_t = typename __source_value_type_impl<_Source>::type;
242 
243   // SFINAE helper to check that an effective range has value_type char,
244   // as required by path constructors taking a std::locale parameter.
245   // The type _Tp must have already been checked by _Path<Tp> or _Path2<_Tp>.
246   template<typename _Tp, typename _Val = __source_value_t<_Tp>>
247     using __value_type_is_char
248       = std::enable_if_t<std::is_same_v<_Val, char>, _Val>;
249 
250   // As above, but also allows char8_t, as required by u8path
251   // C++20 [depr.fs.path.factory]
252   template<typename _Tp, typename _Val = __source_value_t<_Tp>>
253     using __value_type_is_char_or_char8_t
254       = std::enable_if_t<std::is_same_v<_Val, char>
255 #ifdef _GLIBCXX_USE_CHAR8_T
256 			 || std::is_same_v<_Val, char8_t>
257 #endif
258 			 , _Val>;
259 
260   // Create a basic_string<C> or basic_string_view<C> from an iterator range.
261   template<typename _InputIterator>
262     inline auto
263     __string_from_range(_InputIterator __first, _InputIterator __last)
264     {
265       using _EcharT
266 	= typename std::iterator_traits<_InputIterator>::value_type;
267       static_assert(__is_encoded_char<_EcharT>); // C++17 [fs.req]/3
268 
269       if constexpr (__is_contiguous<_InputIterator>)
270 	{
271 	  // For contiguous iterators we can just return a string view.
272 	  if (auto __len = __last - __first) [[__likely__]]
273 	    return basic_string_view<_EcharT>(&*__first, __len);
274 	  return basic_string_view<_EcharT>();
275 	}
276       else
277 	{
278 	  // Conversion requires contiguous characters, so create a string.
279 	  return basic_string<__unified_u8_t<_EcharT>>(__first, __last);
280 	}
281     }
282 
283   /// @} group filesystem
284 } // namespace __detail
285   /// @endcond
286 
287   /// @addtogroup filesystem
288   /// @{
289 
290   /// A filesystem path
291   /// @ingroup filesystem
292   class path
293   {
294   public:
295 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
296     using value_type = wchar_t;
297     static constexpr value_type preferred_separator = L'\\';
298 #else
299 # ifdef _GLIBCXX_DOXYGEN
300     /// Windows uses wchar_t for path::value_type, POSIX uses char.
301     using value_type = __os_dependent__;
302 # else
303     using value_type =  char;
304 # endif
305     static constexpr value_type preferred_separator = '/';
306 #endif
307     using string_type = std::basic_string<value_type>;
308 
309     /// path::format is ignored in this implementation
310     enum format : unsigned char { native_format, generic_format, auto_format };
311 
312     // constructors and destructor
313 
314     path() noexcept { }
315 
316     path(const path& __p) = default;
317 
318     path(path&& __p) noexcept
319     : _M_pathname(std::move(__p._M_pathname)),
320       _M_cmpts(std::move(__p._M_cmpts))
321     { __p.clear(); }
322 
323     path(string_type&& __source, format = auto_format)
324     : _M_pathname(std::move(__source))
325     { _M_split_cmpts(); }
326 
327     template<typename _Source,
328 	     typename _Require = __detail::_Path<_Source>>
329       path(_Source const& __source, format = auto_format)
330       : _M_pathname(_S_convert(__detail::__effective_range(__source)))
331       { _M_split_cmpts(); }
332 
333     template<typename _InputIterator,
334 	     typename _Require = __detail::_Path2<_InputIterator>>
335       path(_InputIterator __first, _InputIterator __last, format = auto_format)
336       : _M_pathname(_S_convert(__detail::__string_from_range(__first, __last)))
337       { _M_split_cmpts(); }
338 
339     template<typename _Source,
340 	     typename _Require = __detail::_Path<_Source>,
341 	     typename _Require2 = __detail::__value_type_is_char<_Source>>
342       path(_Source const& __src, const locale& __loc, format = auto_format)
343       : _M_pathname(_S_convert_loc(__detail::__effective_range(__src), __loc))
344       { _M_split_cmpts(); }
345 
346     template<typename _InputIterator,
347 	     typename _Require = __detail::_Path2<_InputIterator>,
348 	     typename _Req2 = __detail::__value_type_is_char<_InputIterator>>
349       path(_InputIterator __first, _InputIterator __last, const locale& __loc,
350 	   format = auto_format)
351       : _M_pathname(_S_convert_loc(__first, __last, __loc))
352       { _M_split_cmpts(); }
353 
354     ~path() = default;
355 
356     // assignments
357 
358     path& operator=(const path&);
359     path& operator=(path&&) noexcept;
360     path& operator=(string_type&& __source);
361     path& assign(string_type&& __source);
362 
363     template<typename _Source>
364       __detail::_Path<_Source>&
365       operator=(_Source const& __source)
366       { return *this = path(__source); }
367 
368     template<typename _Source>
369       __detail::_Path<_Source>&
370       assign(_Source const& __source)
371       { return *this = path(__source); }
372 
373     template<typename _InputIterator>
374       __detail::_Path2<_InputIterator>&
375       assign(_InputIterator __first, _InputIterator __last)
376       { return *this = path(__first, __last); }
377 
378     // appends
379 
380     path& operator/=(const path& __p);
381 
382     template<typename _Source>
383       __detail::_Path<_Source>&
384       operator/=(_Source const& __source)
385       {
386 	_M_append(_S_convert(__detail::__effective_range(__source)));
387 	return *this;
388       }
389 
390     template<typename _Source>
391       __detail::_Path<_Source>&
392       append(_Source const& __source)
393       {
394 	_M_append(_S_convert(__detail::__effective_range(__source)));
395 	return *this;
396       }
397 
398     template<typename _InputIterator>
399       __detail::_Path2<_InputIterator>&
400       append(_InputIterator __first, _InputIterator __last)
401       {
402 	_M_append(_S_convert(__detail::__string_from_range(__first, __last)));
403 	return *this;
404       }
405 
406     // concatenation
407 
408     path& operator+=(const path& __x);
409     path& operator+=(const string_type& __x);
410     path& operator+=(const value_type* __x);
411     path& operator+=(value_type __x);
412     path& operator+=(basic_string_view<value_type> __x);
413 
414     template<typename _Source>
415       __detail::_Path<_Source>&
416       operator+=(_Source const& __x) { return concat(__x); }
417 
418     template<typename _CharT>
419       __detail::_Path2<_CharT*>&
420       operator+=(_CharT __x);
421 
422     template<typename _Source>
423       __detail::_Path<_Source>&
424       concat(_Source const& __x)
425       {
426 	_M_concat(_S_convert(__detail::__effective_range(__x)));
427 	return *this;
428       }
429 
430     template<typename _InputIterator>
431       __detail::_Path2<_InputIterator>&
432       concat(_InputIterator __first, _InputIterator __last)
433       {
434 	_M_concat(_S_convert(__detail::__string_from_range(__first, __last)));
435 	return *this;
436       }
437 
438     // modifiers
439 
440     void clear() noexcept { _M_pathname.clear(); _M_split_cmpts(); }
441 
442     path& make_preferred();
443     path& remove_filename();
444     path& replace_filename(const path& __replacement);
445     path& replace_extension(const path& __replacement = path());
446 
447     void swap(path& __rhs) noexcept;
448 
449     // native format observers
450 
451     const string_type&  native() const noexcept { return _M_pathname; }
452     const value_type*   c_str() const noexcept { return _M_pathname.c_str(); }
453     operator string_type() const { return _M_pathname; }
454 
455     template<typename _CharT, typename _Traits = std::char_traits<_CharT>,
456 	     typename _Allocator = std::allocator<_CharT>>
457       std::basic_string<_CharT, _Traits, _Allocator>
458       string(const _Allocator& __a = _Allocator()) const;
459 
460     std::string    string() const;
461 #if _GLIBCXX_USE_WCHAR_T
462     std::wstring   wstring() const;
463 #endif
464 #ifdef _GLIBCXX_USE_CHAR8_T
465     __attribute__((__abi_tag__("__u8")))
466     std::u8string  u8string() const;
467 #else
468     std::string    u8string() const;
469 #endif // _GLIBCXX_USE_CHAR8_T
470     std::u16string u16string() const;
471     std::u32string u32string() const;
472 
473     // generic format observers
474     template<typename _CharT, typename _Traits = std::char_traits<_CharT>,
475 	     typename _Allocator = std::allocator<_CharT>>
476       std::basic_string<_CharT, _Traits, _Allocator>
477       generic_string(const _Allocator& __a = _Allocator()) const;
478 
479     std::string    generic_string() const;
480 #if _GLIBCXX_USE_WCHAR_T
481     std::wstring   generic_wstring() const;
482 #endif
483 #ifdef _GLIBCXX_USE_CHAR8_T
484     __attribute__((__abi_tag__("__u8")))
485     std::u8string  generic_u8string() const;
486 #else
487     std::string    generic_u8string() const;
488 #endif // _GLIBCXX_USE_CHAR8_T
489     std::u16string generic_u16string() const;
490     std::u32string generic_u32string() const;
491 
492     // compare
493 
494     int compare(const path& __p) const noexcept;
495     int compare(const string_type& __s) const noexcept;
496     int compare(const value_type* __s) const noexcept;
497     int compare(basic_string_view<value_type> __s) const noexcept;
498 
499     // decomposition
500 
501     path root_name() const;
502     path root_directory() const;
503     path root_path() const;
504     path relative_path() const;
505     path parent_path() const;
506     path filename() const;
507     path stem() const;
508     path extension() const;
509 
510     // query
511 
512     [[nodiscard]] bool empty() const noexcept { return _M_pathname.empty(); }
513     bool has_root_name() const noexcept;
514     bool has_root_directory() const noexcept;
515     bool has_root_path() const noexcept;
516     bool has_relative_path() const noexcept;
517     bool has_parent_path() const noexcept;
518     bool has_filename() const noexcept;
519     bool has_stem() const noexcept;
520     bool has_extension() const noexcept;
521     bool is_absolute() const noexcept;
522     bool is_relative() const noexcept { return !is_absolute(); }
523 
524     // generation
525     path lexically_normal() const;
526     path lexically_relative(const path& base) const;
527     path lexically_proximate(const path& base) const;
528 
529     // iterators
530     class iterator;
531     using const_iterator = iterator;
532 
533     iterator begin() const noexcept;
534     iterator end() const noexcept;
535 
536     /// Write a path to a stream
537     template<typename _CharT, typename _Traits>
538       friend std::basic_ostream<_CharT, _Traits>&
539       operator<<(std::basic_ostream<_CharT, _Traits>& __os, const path& __p)
540       {
541 	__os << std::quoted(__p.string<_CharT, _Traits>());
542 	return __os;
543       }
544 
545     /// Read a path from a stream
546     template<typename _CharT, typename _Traits>
547       friend std::basic_istream<_CharT, _Traits>&
548       operator>>(std::basic_istream<_CharT, _Traits>& __is, path& __p)
549       {
550 	std::basic_string<_CharT, _Traits> __tmp;
551 	if (__is >> std::quoted(__tmp))
552 	  __p = std::move(__tmp);
553 	return __is;
554       }
555 
556     // non-member operators
557 
558     /// Compare paths
559     friend bool operator==(const path& __lhs, const path& __rhs) noexcept
560     { return path::_S_compare(__lhs, __rhs) == 0; }
561 
562 #if __cpp_lib_three_way_comparison
563     /// Compare paths
564     friend strong_ordering
565     operator<=>(const path& __lhs, const path& __rhs) noexcept
566     { return path::_S_compare(__lhs, __rhs) <=> 0; }
567 #else
568     /// Compare paths
569     friend bool operator!=(const path& __lhs, const path& __rhs) noexcept
570     { return !(__lhs == __rhs); }
571 
572     /// Compare paths
573     friend bool operator<(const path& __lhs, const path& __rhs) noexcept
574     { return __lhs.compare(__rhs) < 0; }
575 
576     /// Compare paths
577     friend bool operator<=(const path& __lhs, const path& __rhs) noexcept
578     { return !(__rhs < __lhs); }
579 
580     /// Compare paths
581     friend bool operator>(const path& __lhs, const path& __rhs) noexcept
582     { return __rhs < __lhs; }
583 
584     /// Compare paths
585     friend bool operator>=(const path& __lhs, const path& __rhs) noexcept
586     { return !(__lhs < __rhs); }
587 #endif
588 
589     /// Append one path to another
590     friend path operator/(const path& __lhs, const path& __rhs)
591     {
592       path __result(__lhs);
593       __result /= __rhs;
594       return __result;
595     }
596 
597   private:
598     enum class _Type : unsigned char {
599       _Multi = 0, _Root_name, _Root_dir, _Filename
600     };
601 
602     path(basic_string_view<value_type> __str, _Type __type);
603 
604     enum class _Split { _Stem, _Extension };
605 
606     void _M_append(basic_string_view<value_type>);
607     void _M_concat(basic_string_view<value_type>);
608 
609     pair<const string_type*, size_t> _M_find_extension() const noexcept;
610 
611     // path::_S_convert creates a basic_string<value_type> or
612     // basic_string_view<value_type> from a basic_string<C> or
613     // basic_string_view<C>, for an encoded character type C,
614     // performing the conversions required by [fs.path.type.cvt].
615     template<typename _Tp>
616       static auto
617       _S_convert(_Tp __str)
618       noexcept(is_same_v<typename _Tp::value_type, value_type>)
619       {
620 	if constexpr (is_same_v<typename _Tp::value_type, value_type>)
621 	  return __str; // No conversion needed.
622 #if !defined _GLIBCXX_FILESYSTEM_IS_WINDOWS && defined _GLIBCXX_USE_CHAR8_T
623 	else if constexpr (is_same_v<_Tp, std::u8string>)
624 	  // Calling _S_convert<char8_t> will return a u8string_view that
625 	  // refers to __str and would dangle after this function returns.
626 	  // Return a string_type instead, to avoid dangling.
627 	  return string_type(_S_convert(__str.data(),
628 					__str.data() + __str.size()));
629 #endif
630 	else
631 	  return _S_convert(__str.data(), __str.data() + __str.size());
632       }
633 
634     template<typename _EcharT>
635       static auto
636       _S_convert(const _EcharT* __first, const _EcharT* __last);
637 
638     // _S_convert_loc converts a range of char to string_type, using the
639     // supplied locale for encoding conversions.
640 
641     static string_type
642     _S_convert_loc(const char* __first, const char* __last,
643 		   const std::locale& __loc);
644 
645     template<typename _Iter>
646       static string_type
647       _S_convert_loc(_Iter __first, _Iter __last, const std::locale& __loc)
648       {
649 	const auto __s = __detail::__string_from_range(__first, __last);
650 	return _S_convert_loc(__s.data(), __s.data() + __s.size(), __loc);
651       }
652 
653     template<typename _Tp>
654       static string_type
655       _S_convert_loc(const _Tp& __s, const std::locale& __loc)
656       {
657 	return _S_convert_loc(__s.data(), __s.data() + __s.size(), __loc);
658       }
659 
660     template<typename _CharT, typename _Traits, typename _Allocator>
661       static basic_string<_CharT, _Traits, _Allocator>
662       _S_str_convert(basic_string_view<value_type>, const _Allocator&);
663 
664     // Returns lhs.compare(rhs), but defined after path::iterator is complete.
665     __attribute__((__always_inline__))
666     static int
667     _S_compare(const path& __lhs, const path& __rhs) noexcept;
668 
669     void _M_split_cmpts();
670 
671     _Type _M_type() const noexcept { return _M_cmpts.type(); }
672 
673     string_type _M_pathname;
674 
675     struct _Cmpt;
676 
677     struct _List
678     {
679       using value_type = _Cmpt;
680       using iterator = value_type*;
681       using const_iterator = const value_type*;
682 
683       _List();
684       _List(const _List&);
685       _List(_List&&) = default;
686       _List& operator=(const _List&);
687       _List& operator=(_List&&) = default;
688       ~_List() = default;
689 
690       _Type type() const noexcept
691       { return _Type(reinterpret_cast<uintptr_t>(_M_impl.get()) & 0x3); }
692 
693       void type(_Type) noexcept;
694 
695       int size() const noexcept; // zero unless type() == _Type::_Multi
696       bool empty() const noexcept; // true unless type() == _Type::_Multi
697       void clear();
698       void swap(_List& __l) noexcept { _M_impl.swap(__l._M_impl); }
699       int capacity() const noexcept;
700       void reserve(int, bool); ///< @pre type() == _Type::_Multi
701 
702       // All the member functions below here have a precondition !empty()
703       // (and they should only be called from within the library).
704 
705       iterator begin() noexcept;
706       iterator end() noexcept;
707       const_iterator begin() const noexcept;
708       const_iterator end() const noexcept;
709 
710       value_type& front() noexcept;
711       value_type& back() noexcept;
712       const value_type& front() const noexcept;
713       const value_type& back() const noexcept;
714 
715       void pop_back();
716       void _M_erase_from(const_iterator __pos); // erases [__pos,end())
717 
718       struct _Impl;
719       struct _Impl_deleter
720       {
721 	void operator()(_Impl*) const noexcept;
722       };
723       unique_ptr<_Impl, _Impl_deleter> _M_impl;
724     };
725     _List _M_cmpts;
726 
727     struct _Parser;
728 
729     template<typename _EcharT> struct _Codecvt;
730   };
731 
732   /// @{
733   /// @relates std::filesystem::path
734 
735 #if __cpp_concepts >= 201907L
736   // Workaround for PR libstdc++/106201
737   inline void
738   swap(same_as<path> auto& __lhs, same_as<path> auto& __rhs) noexcept
739   { __lhs.swap(__rhs); }
740 #else
741   inline void swap(path& __lhs, path& __rhs) noexcept { __lhs.swap(__rhs); }
742 #endif
743 
744   size_t hash_value(const path& __p) noexcept;
745 
746   /// @}
747 
748   /// Exception type thrown by the Filesystem library
749   class filesystem_error : public std::system_error
750   {
751   public:
752     filesystem_error(const string& __what_arg, error_code __ec);
753 
754     filesystem_error(const string& __what_arg, const path& __p1,
755 		     error_code __ec);
756 
757     filesystem_error(const string& __what_arg, const path& __p1,
758 		     const path& __p2, error_code __ec);
759 
760     filesystem_error(const filesystem_error&) = default;
761     filesystem_error& operator=(const filesystem_error&) = default;
762 
763     // No move constructor or assignment operator.
764     // Copy rvalues instead, so that _M_impl is not left empty.
765 
766     ~filesystem_error();
767 
768     const path& path1() const noexcept;
769     const path& path2() const noexcept;
770     const char* what() const noexcept;
771 
772   private:
773     struct _Impl;
774     std::__shared_ptr<const _Impl> _M_impl;
775   };
776 
777   /// @cond undocumented
778 namespace __detail
779 {
780   [[noreturn]] inline void
781   __throw_conversion_error()
782   {
783     _GLIBCXX_THROW_OR_ABORT(filesystem_error(
784 	 "Cannot convert character sequence",
785 	 std::make_error_code(errc::illegal_byte_sequence)));
786   }
787 
788 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
789   template<typename _Tp>
790     inline std::wstring
791     __wstr_from_utf8(const _Tp& __str)
792     {
793       static_assert(std::is_same_v<typename _Tp::value_type, char>);
794       std::wstring __wstr;
795       // XXX This assumes native wide encoding is UTF-16.
796       std::codecvt_utf8_utf16<wchar_t> __wcvt;
797       const auto __p = __str.data();
798       if (!__str_codecvt_in_all(__p, __p + __str.size(), __wstr, __wcvt))
799 	__detail::__throw_conversion_error();
800       return __wstr;
801     }
802 #endif
803 
804 } // namespace __detail
805   /// @endcond
806 
807 
808   /** Create a path from a UTF-8-encoded sequence of char
809    *
810    * @relates std::filesystem::path
811    */
812   template<typename _InputIterator,
813 	   typename _Require = __detail::_Path2<_InputIterator>,
814 	   typename _CharT
815 	     = __detail::__value_type_is_char_or_char8_t<_InputIterator>>
816     inline path
817     u8path(_InputIterator __first, _InputIterator __last)
818     {
819 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
820       if constexpr (is_same_v<_CharT, char>)
821 	return path{ __detail::__wstr_from_utf8(
822 	    __detail::__string_from_range(__first, __last)) };
823       else
824 	return path{ __first, __last }; // constructor handles char8_t
825 #else
826       // This assumes native normal encoding is UTF-8.
827       return path{ __first, __last };
828 #endif
829     }
830 
831   /** Create a path from a UTF-8-encoded sequence of char
832    *
833    * @relates std::filesystem::path
834    */
835   template<typename _Source,
836 	   typename _Require = __detail::_Path<_Source>,
837 	   typename _CharT = __detail::__value_type_is_char_or_char8_t<_Source>>
838     inline path
839     u8path(const _Source& __source)
840     {
841 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
842       if constexpr (is_same_v<_CharT, char>)
843 	return path{ __detail::__wstr_from_utf8(
844 	    __detail::__effective_range(__source)) };
845       else
846 	return path{ __source }; // constructor handles char8_t
847 #else
848       // This assumes native normal encoding is UTF-8.
849       return path{ __source };
850 #endif
851     }
852 
853   /// @cond undocumented
854 
855   struct path::_Cmpt : path
856   {
857     _Cmpt(basic_string_view<value_type> __s, _Type __t, size_t __pos);
858 
859     _Cmpt() : _M_pos(-1) { }
860 
861     size_t _M_pos;
862   };
863 
864   // path::_Codecvt<C> Performs conversions between C and path::string_type.
865   // The native encoding of char strings is the OS-dependent current
866   // encoding for pathnames. FIXME: We assume this is UTF-8 everywhere,
867   // but should use a Windows API to query it.
868 
869   // Converts between native pathname encoding and char16_t or char32_t.
870   template<typename _EcharT>
871     struct path::_Codecvt
872     // Need derived class here because std::codecvt has protected destructor.
873     : std::codecvt<_EcharT, char, mbstate_t>
874     { };
875 
876   // Converts between native pathname encoding and native wide encoding.
877   // The native encoding for wide strings is the execution wide-character
878   // set encoding. FIXME: We assume that this is either UTF-32 or UTF-16
879   // (depending on the width of wchar_t). That matches GCC's default,
880   // but can be changed with -fwide-exec-charset.
881   // We need a custom codecvt converting the native pathname encoding
882   // to/from the native wide encoding.
883   template<>
884     struct path::_Codecvt<wchar_t>
885     : __conditional_t<sizeof(wchar_t) == sizeof(char32_t),
886 		      std::codecvt_utf8<wchar_t>,       // UTF-8 <-> UTF-32
887 		      std::codecvt_utf8_utf16<wchar_t>> // UTF-8 <-> UTF-16
888     { };
889 
890   template<typename _EcharT>
891     auto
892     path::_S_convert(const _EcharT* __f, const _EcharT* __l)
893     {
894       static_assert(__detail::__is_encoded_char<_EcharT>);
895 
896 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
897 # define _GLIBCXX_CONV_FROM_UTF8(S) __detail::__wstr_from_utf8(S)
898 #else
899 # define _GLIBCXX_CONV_FROM_UTF8(S) S
900 #endif
901 
902       if constexpr (is_same_v<_EcharT, value_type>)
903 	return basic_string_view<value_type>(__f, __l - __f);
904 #ifdef _GLIBCXX_USE_CHAR8_T
905       else if constexpr (is_same_v<_EcharT, char8_t>)
906 	{
907 	  string_view __str(reinterpret_cast<const char*>(__f), __l - __f);
908 	  return _GLIBCXX_CONV_FROM_UTF8(__str);
909 	}
910 #endif
911 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
912       else if constexpr (is_same_v<_EcharT, char>)
913 	{
914 	  std::wstring __wstr;
915 	  path::_Codecvt<wchar_t> __cvt;
916 	  if (__str_codecvt_in_all(__f, __l, __wstr, __cvt))
917 	    return __wstr;
918 	}
919 #endif
920       else
921 	{
922 	  path::_Codecvt<_EcharT> __cvt;
923 	  std::string __str;
924 	  if (__str_codecvt_out_all(__f, __l, __str, __cvt))
925 	    return _GLIBCXX_CONV_FROM_UTF8(__str);
926 	}
927       __detail::__throw_conversion_error();
928     }
929 #undef _GLIBCXX_CONV_FROM_UTF8
930 
931   /// @endcond
932 
933   /// An iterator for the components of a path
934   class path::iterator
935   {
936   public:
937     using difference_type	= std::ptrdiff_t;
938     using value_type		= path;
939     using reference		= const path&;
940     using pointer		= const path*;
941     using iterator_category	= std::bidirectional_iterator_tag;
942 
943     iterator() noexcept : _M_path(nullptr), _M_cur(), _M_at_end() { }
944 
945     iterator(const iterator&) = default;
946     iterator& operator=(const iterator&) = default;
947 
948     reference operator*() const noexcept;
949     pointer   operator->() const noexcept { return std::__addressof(**this); }
950 
951     iterator& operator++() noexcept;
952 
953     iterator  operator++(int) noexcept
954     { auto __tmp = *this; ++*this; return __tmp; }
955 
956     iterator& operator--() noexcept;
957 
958     iterator  operator--(int) noexcept
959     { auto __tmp = *this; --*this; return __tmp; }
960 
961     friend bool
962     operator==(const iterator& __lhs, const iterator& __rhs) noexcept
963     { return __lhs._M_equals(__rhs); }
964 
965     friend bool
966     operator!=(const iterator& __lhs, const iterator& __rhs) noexcept
967     { return !__lhs._M_equals(__rhs); }
968 
969   private:
970     friend class path;
971 
972     bool
973     _M_is_multi() const noexcept
974     { return _M_path->_M_type() == _Type::_Multi; }
975 
976     friend difference_type
977     __path_iter_distance(const iterator& __first, const iterator& __last)
978     noexcept
979     {
980       __glibcxx_assert(__first._M_path != nullptr);
981       __glibcxx_assert(__first._M_path == __last._M_path);
982       if (__first._M_is_multi())
983 	return std::distance(__first._M_cur, __last._M_cur);
984       else if (__first._M_at_end == __last._M_at_end)
985 	return 0;
986       else
987 	return __first._M_at_end ? -1 : 1;
988     }
989 
990     friend void
991     __path_iter_advance(iterator& __i, difference_type __n) noexcept
992     {
993       if (__n == 1)
994 	++__i;
995       else if (__n == -1)
996 	--__i;
997       else if (__n != 0)
998 	{
999 	  __glibcxx_assert(__i._M_path != nullptr);
1000 	  __glibcxx_assert(__i._M_is_multi());
1001 	  // __glibcxx_assert(__i._M_path->_M_cmpts.end() - __i._M_cur >= __n);
1002 	  __i._M_cur += __n;
1003 	}
1004     }
1005 
1006     iterator(const path* __path, path::_List::const_iterator __iter) noexcept
1007     : _M_path(__path), _M_cur(__iter), _M_at_end()
1008     { }
1009 
1010     iterator(const path* __path, bool __at_end) noexcept
1011     : _M_path(__path), _M_cur(), _M_at_end(__at_end)
1012     { }
1013 
1014     bool _M_equals(iterator) const noexcept;
1015 
1016     const path* 		_M_path;
1017     path::_List::const_iterator _M_cur;
1018     bool			_M_at_end;  // only used when type != _Multi
1019   };
1020 
1021 
1022   inline path&
1023   path::operator=(path&& __p) noexcept
1024   {
1025     if (&__p == this) [[__unlikely__]]
1026       return *this;
1027 
1028     _M_pathname = std::move(__p._M_pathname);
1029     _M_cmpts = std::move(__p._M_cmpts);
1030     __p.clear();
1031     return *this;
1032   }
1033 
1034   inline path&
1035   path::operator=(string_type&& __source)
1036   { return *this = path(std::move(__source)); }
1037 
1038   inline path&
1039   path::assign(string_type&& __source)
1040   { return *this = path(std::move(__source)); }
1041 
1042   inline path&
1043   path::operator+=(const string_type& __x)
1044   {
1045     _M_concat(__x);
1046     return *this;
1047   }
1048 
1049   inline path&
1050   path::operator+=(const value_type* __x)
1051   {
1052     _M_concat(__x);
1053     return *this;
1054   }
1055 
1056   inline path&
1057   path::operator+=(value_type __x)
1058   {
1059     _M_concat(basic_string_view<value_type>(&__x, 1));
1060     return *this;
1061   }
1062 
1063   inline path&
1064   path::operator+=(basic_string_view<value_type> __x)
1065   {
1066     _M_concat(__x);
1067     return *this;
1068   }
1069 
1070   template<typename _CharT>
1071     inline __detail::_Path2<_CharT*>&
1072     path::operator+=(const _CharT __x)
1073     {
1074       _M_concat(_S_convert(&__x, &__x + 1));
1075       return *this;
1076     }
1077 
1078   inline path&
1079   path::make_preferred()
1080   {
1081 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1082     auto __pos = _M_pathname.find(L'/');
1083     while (__pos != _M_pathname.npos)
1084       {
1085 	_M_pathname[__pos] = preferred_separator;
1086 	__pos = _M_pathname.find(L'/', __pos);
1087       }
1088 #endif
1089     return *this;
1090   }
1091 
1092   inline void path::swap(path& __rhs) noexcept
1093   {
1094     _M_pathname.swap(__rhs._M_pathname);
1095     _M_cmpts.swap(__rhs._M_cmpts);
1096   }
1097 
1098   /// @cond undocumented
1099   template<typename _CharT, typename _Traits, typename _Allocator>
1100     std::basic_string<_CharT, _Traits, _Allocator>
1101     path::_S_str_convert(basic_string_view<value_type> __str,
1102 			 const _Allocator& __a)
1103     {
1104       static_assert(!is_same_v<_CharT, value_type>);
1105 
1106       using _WString = basic_string<_CharT, _Traits, _Allocator>;
1107 
1108       if (__str.size() == 0)
1109 	return _WString(__a);
1110 
1111 #ifndef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1112       string_view __u8str = __str;
1113 #else
1114       // First convert native string from UTF-16 to to UTF-8.
1115       // XXX This assumes that the execution wide-character set is UTF-16.
1116       std::codecvt_utf8_utf16<value_type> __cvt;
1117 
1118       using _CharAlloc = __alloc_rebind<_Allocator, char>;
1119       using _String = basic_string<char, char_traits<char>, _CharAlloc>;
1120       _String __u8str{_CharAlloc{__a}};
1121       const value_type* __wfirst = __str.data();
1122       const value_type* __wlast = __wfirst + __str.size();
1123       if (!__str_codecvt_out_all(__wfirst, __wlast, __u8str, __cvt))
1124 	__detail::__throw_conversion_error();
1125       if constexpr (is_same_v<_CharT, char>)
1126 	return __u8str; // XXX assumes native ordinary encoding is UTF-8.
1127       else
1128 #endif
1129 	{
1130 	  const char* __first = __u8str.data();
1131 	  const char* __last = __first + __u8str.size();
1132 
1133 	  // Convert UTF-8 string to requested format.
1134 #ifdef _GLIBCXX_USE_CHAR8_T
1135 	  if constexpr (is_same_v<_CharT, char8_t>)
1136 	    return _WString(__first, __last, __a);
1137 	  else
1138 #endif
1139 	    {
1140 	      // Convert UTF-8 to wide string.
1141 	      _WString __wstr(__a);
1142 	      path::_Codecvt<_CharT> __cvt;
1143 	      if (__str_codecvt_in_all(__first, __last, __wstr, __cvt))
1144 		return __wstr;
1145 	    }
1146 	}
1147       __detail::__throw_conversion_error();
1148     }
1149   /// @endcond
1150 
1151   template<typename _CharT, typename _Traits, typename _Allocator>
1152     inline basic_string<_CharT, _Traits, _Allocator>
1153     path::string(const _Allocator& __a) const
1154     {
1155       if constexpr (is_same_v<_CharT, value_type>)
1156 	return { _M_pathname.c_str(), _M_pathname.length(), __a };
1157       else
1158 	return _S_str_convert<_CharT, _Traits>(_M_pathname, __a);
1159     }
1160 
1161   inline std::string
1162   path::string() const { return string<char>(); }
1163 
1164 #if _GLIBCXX_USE_WCHAR_T
1165   inline std::wstring
1166   path::wstring() const { return string<wchar_t>(); }
1167 #endif
1168 
1169 #ifdef _GLIBCXX_USE_CHAR8_T
1170   inline std::u8string
1171   path::u8string() const { return string<char8_t>(); }
1172 #else
1173   inline std::string
1174   path::u8string() const
1175   {
1176 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1177     std::string __str;
1178     // convert from native wide encoding (assumed to be UTF-16) to UTF-8
1179     std::codecvt_utf8_utf16<value_type> __cvt;
1180     const value_type* __first = _M_pathname.data();
1181     const value_type* __last = __first + _M_pathname.size();
1182     if (__str_codecvt_out_all(__first, __last, __str, __cvt))
1183       return __str;
1184     __detail::__throw_conversion_error();
1185 #else
1186     return _M_pathname;
1187 #endif
1188   }
1189 #endif // _GLIBCXX_USE_CHAR8_T
1190 
1191   inline std::u16string
1192   path::u16string() const { return string<char16_t>(); }
1193 
1194   inline std::u32string
1195   path::u32string() const { return string<char32_t>(); }
1196 
1197   template<typename _CharT, typename _Traits, typename _Allocator>
1198     inline std::basic_string<_CharT, _Traits, _Allocator>
1199     path::generic_string(const _Allocator& __a) const
1200     {
1201 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1202       const value_type __slash = L'/';
1203 #else
1204       const value_type __slash = '/';
1205 #endif
1206       using _Alloc2 = typename allocator_traits<_Allocator>::template
1207 	rebind_alloc<value_type>;
1208       basic_string<value_type, char_traits<value_type>, _Alloc2> __str(__a);
1209 
1210       if (_M_type() == _Type::_Root_dir)
1211 	__str.assign(1, __slash);
1212       else
1213 	{
1214 	  __str.reserve(_M_pathname.size());
1215 	  bool __add_slash = false;
1216 	  for (auto& __elem : *this)
1217 	    {
1218 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1219 	      if (__elem._M_type() == _Type::_Root_dir)
1220 		{
1221 		  __str += __slash;
1222 		  continue;
1223 		}
1224 #endif
1225 	      if (__add_slash)
1226 		__str += __slash;
1227 	      __str += basic_string_view<value_type>(__elem._M_pathname);
1228 	      __add_slash = __elem._M_type() == _Type::_Filename;
1229 	    }
1230 	}
1231 
1232       if constexpr (is_same_v<_CharT, value_type>)
1233 	return __str;
1234       else
1235 	return _S_str_convert<_CharT, _Traits>(__str, __a);
1236     }
1237 
1238   inline std::string
1239   path::generic_string() const
1240   { return generic_string<char>(); }
1241 
1242 #if _GLIBCXX_USE_WCHAR_T
1243   inline std::wstring
1244   path::generic_wstring() const
1245   { return generic_string<wchar_t>(); }
1246 #endif
1247 
1248 #ifdef _GLIBCXX_USE_CHAR8_T
1249   inline std::u8string
1250   path::generic_u8string() const
1251   { return generic_string<char8_t>(); }
1252 #else
1253   inline std::string
1254   path::generic_u8string() const
1255   { return generic_string(); }
1256 #endif
1257 
1258   inline std::u16string
1259   path::generic_u16string() const
1260   { return generic_string<char16_t>(); }
1261 
1262   inline std::u32string
1263   path::generic_u32string() const
1264   { return generic_string<char32_t>(); }
1265 
1266   inline int
1267   path::compare(const string_type& __s) const noexcept
1268   { return compare(basic_string_view<value_type>(__s)); }
1269 
1270   inline int
1271   path::compare(const value_type* __s) const noexcept
1272   { return compare(basic_string_view<value_type>(__s)); }
1273 
1274   inline path
1275   path::filename() const
1276   {
1277     if (empty())
1278       return {};
1279     else if (_M_type() == _Type::_Filename)
1280       return *this;
1281     else if (_M_type() == _Type::_Multi)
1282       {
1283 	if (_M_pathname.back() == preferred_separator)
1284 	  return {};
1285 	auto __last = --end();
1286 	if (__last->_M_type() == _Type::_Filename)
1287 	  return *__last;
1288       }
1289     return {};
1290   }
1291 
1292   inline path
1293   path::stem() const
1294   {
1295     auto ext = _M_find_extension();
1296     if (ext.first && ext.second != 0)
1297       return path{ext.first->substr(0, ext.second)};
1298     return {};
1299   }
1300 
1301   inline path
1302   path::extension() const
1303   {
1304     auto ext = _M_find_extension();
1305     if (ext.first && ext.second != string_type::npos)
1306       return path{ext.first->substr(ext.second)};
1307     return {};
1308   }
1309 
1310   inline bool
1311   path::has_stem() const noexcept
1312   {
1313     auto ext = _M_find_extension();
1314     return ext.first && ext.second != 0;
1315   }
1316 
1317   inline bool
1318   path::has_extension() const noexcept
1319   {
1320     auto ext = _M_find_extension();
1321     return ext.first && ext.second != string_type::npos;
1322   }
1323 
1324   inline bool
1325   path::is_absolute() const noexcept
1326   {
1327 #ifdef _GLIBCXX_FILESYSTEM_IS_WINDOWS
1328     return has_root_name() && has_root_directory();
1329 #else
1330     return has_root_directory();
1331 #endif
1332   }
1333 
1334   inline path::iterator
1335   path::begin() const noexcept
1336   {
1337     if (_M_type() == _Type::_Multi)
1338       return iterator(this, _M_cmpts.begin());
1339     return iterator(this, empty());
1340   }
1341 
1342   inline path::iterator
1343   path::end() const noexcept
1344   {
1345     if (_M_type() == _Type::_Multi)
1346       return iterator(this, _M_cmpts.end());
1347     return iterator(this, true);
1348   }
1349 
1350   inline path::iterator&
1351   path::iterator::operator++() noexcept
1352   {
1353     __glibcxx_assert(_M_path != nullptr);
1354     if (_M_is_multi())
1355       {
1356 	__glibcxx_assert(_M_cur != _M_path->_M_cmpts.end());
1357 	++_M_cur;
1358       }
1359     else
1360       {
1361 	__glibcxx_assert(!_M_at_end);
1362 	_M_at_end = true;
1363       }
1364     return *this;
1365   }
1366 
1367   inline path::iterator&
1368   path::iterator::operator--() noexcept
1369   {
1370     __glibcxx_assert(_M_path != nullptr);
1371     if (_M_is_multi())
1372       {
1373 	__glibcxx_assert(_M_cur != _M_path->_M_cmpts.begin());
1374 	--_M_cur;
1375       }
1376     else
1377       {
1378 	__glibcxx_assert(_M_at_end);
1379 	_M_at_end = false;
1380       }
1381     return *this;
1382   }
1383 
1384   inline path::iterator::reference
1385   path::iterator::operator*() const noexcept
1386   {
1387     __glibcxx_assert(_M_path != nullptr);
1388     if (_M_is_multi())
1389       {
1390 	__glibcxx_assert(_M_cur != _M_path->_M_cmpts.end());
1391 	return *_M_cur;
1392       }
1393     return *_M_path;
1394   }
1395 
1396   inline bool
1397   path::iterator::_M_equals(iterator __rhs) const noexcept
1398   {
1399     if (_M_path != __rhs._M_path)
1400       return false;
1401     if (_M_path == nullptr)
1402       return true;
1403     if (_M_is_multi())
1404       return _M_cur == __rhs._M_cur;
1405     return _M_at_end == __rhs._M_at_end;
1406   }
1407 
1408   // Define this now that path and path::iterator are complete.
1409   // It needs to consider the string_view(Range&&) constructor during
1410   // overload resolution, which depends on whether range<path> is satisfied,
1411   // which depends on whether path::iterator is complete.
1412   inline int
1413   path::_S_compare(const path& __lhs, const path& __rhs) noexcept
1414   { return __lhs.compare(__rhs); }
1415 
1416   /// @} group filesystem
1417 _GLIBCXX_END_NAMESPACE_CXX11
1418 } // namespace filesystem
1419 
1420 /// @cond undocumented
1421 
1422 inline ptrdiff_t
1423 distance(filesystem::path::iterator __first, filesystem::path::iterator __last)
1424 noexcept
1425 { return __path_iter_distance(__first, __last); }
1426 
1427 template<typename _Distance>
1428   inline void
1429   advance(filesystem::path::iterator& __i, _Distance __n) noexcept
1430   { __path_iter_advance(__i, static_cast<ptrdiff_t>(__n)); }
1431 
1432 extern template class __shared_ptr<const filesystem::filesystem_error::_Impl>;
1433 
1434 /// @endcond
1435 
1436 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1437 // 3657. std::hash<std::filesystem::path> is not enabled
1438 template<>
1439   struct hash<filesystem::path>
1440   {
1441     size_t
1442     operator()(const filesystem::path& __p) const noexcept
1443     { return filesystem::hash_value(__p); }
1444   };
1445 
1446 _GLIBCXX_END_NAMESPACE_VERSION
1447 } // namespace std
1448 
1449 #endif // C++17
1450 
1451 #endif // _GLIBCXX_FS_PATH_H
1452