1// -*- C++ -*-
2//===--------------------------- filesystem -------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10#ifndef _LIBCPP_EXPERIMENTAL_FILESYSTEM
11#define _LIBCPP_EXPERIMENTAL_FILESYSTEM
12/*
13    filesystem synopsis
14
15    namespace std { namespace experimental { namespace filesystem { inline namespace v1 {
16
17    class path;
18
19    void swap(path& lhs, path& rhs) _NOEXCEPT;
20    size_t hash_value(const path& p) _NOEXCEPT;
21
22    bool operator==(const path& lhs, const path& rhs) _NOEXCEPT;
23    bool operator!=(const path& lhs, const path& rhs) _NOEXCEPT;
24    bool operator< (const path& lhs, const path& rhs) _NOEXCEPT;
25    bool operator<=(const path& lhs, const path& rhs) _NOEXCEPT;
26    bool operator> (const path& lhs, const path& rhs) _NOEXCEPT;
27    bool operator>=(const path& lhs, const path& rhs) _NOEXCEPT;
28
29    path operator/ (const path& lhs, const path& rhs);
30
31    template <class charT, class traits>
32    basic_ostream<charT, traits>&
33    operator<<(basic_ostream<charT, traits>& os, const path& p);
34
35    template <class charT, class traits>
36    basic_istream<charT, traits>&
37    operator>>(basic_istream<charT, traits>& is, path& p);
38
39    template <class Source>
40      path u8path(const Source& source);
41    template <class InputIterator>
42      path u8path(InputIterator first, InputIterator last);
43
44    class filesystem_error;
45    class directory_entry;
46
47    class directory_iterator;
48
49    // enable directory_iterator range-based for statements
50    directory_iterator begin(directory_iterator iter) noexcept;
51    directory_iterator end(const directory_iterator&) noexcept;
52
53    class recursive_directory_iterator;
54
55    // enable recursive_directory_iterator range-based for statements
56    recursive_directory_iterator begin(recursive_directory_iterator iter) noexcept;
57    recursive_directory_iterator end(const recursive_directory_iterator&) noexcept;
58
59    class file_status;
60
61    struct space_info
62    {
63      uintmax_t capacity;
64      uintmax_t free;
65      uintmax_t available;
66    };
67
68    enum class file_type;
69    enum class perms;
70    enum class copy_options;
71    enum class directory_options;
72
73    typedef chrono::time_point<trivial-clock>  file_time_type;
74
75    // operational functions
76
77    path absolute(const path& p, const path& base=current_path());
78
79    path canonical(const path& p, const path& base = current_path());
80    path canonical(const path& p, error_code& ec);
81    path canonical(const path& p, const path& base, error_code& ec);
82
83    void copy(const path& from, const path& to);
84    void copy(const path& from, const path& to, error_code& ec) _NOEXCEPT;
85    void copy(const path& from, const path& to, copy_options options);
86    void copy(const path& from, const path& to, copy_options options,
87                   error_code& ec) _NOEXCEPT;
88
89    bool copy_file(const path& from, const path& to);
90    bool copy_file(const path& from, const path& to, error_code& ec) _NOEXCEPT;
91    bool copy_file(const path& from, const path& to, copy_options option);
92    bool copy_file(const path& from, const path& to, copy_options option,
93                           error_code& ec) _NOEXCEPT;
94
95    void copy_symlink(const path& existing_symlink, const path& new_symlink);
96    void copy_symlink(const path& existing_symlink, const path& new_symlink,
97                              error_code& ec) _NOEXCEPT;
98
99    bool create_directories(const path& p);
100    bool create_directories(const path& p, error_code& ec) _NOEXCEPT;
101
102    bool create_directory(const path& p);
103    bool create_directory(const path& p, error_code& ec) _NOEXCEPT;
104
105    bool create_directory(const path& p, const path& attributes);
106    bool create_directory(const path& p, const path& attributes,
107                                  error_code& ec) _NOEXCEPT;
108
109    void create_directory_symlink(const path& to, const path& new_symlink);
110    void create_directory_symlink(const path& to, const path& new_symlink,
111                                          error_code& ec) _NOEXCEPT;
112
113    void create_hard_link(const path& to, const path& new_hard_link);
114    void create_hard_link(const path& to, const path& new_hard_link,
115                                  error_code& ec) _NOEXCEPT;
116
117    void create_symlink(const path& to, const path& new_symlink);
118    void create_symlink(const path& to, const path& new_symlink,
119                                error_code& ec) _NOEXCEPT;
120
121    path current_path();
122    path current_path(error_code& ec);
123    void current_path(const path& p);
124    void current_path(const path& p, error_code& ec) _NOEXCEPT;
125
126    bool exists(file_status s) _NOEXCEPT;
127    bool exists(const path& p);
128    bool exists(const path& p, error_code& ec) _NOEXCEPT;
129
130    bool equivalent(const path& p1, const path& p2);
131    bool equivalent(const path& p1, const path& p2, error_code& ec) _NOEXCEPT;
132
133    uintmax_t    file_size(const path& p);
134    uintmax_t    file_size(const path& p, error_code& ec) _NOEXCEPT;
135
136    uintmax_t    hard_link_count(const path& p);
137    uintmax_t    hard_link_count(const path& p, error_code& ec) _NOEXCEPT;
138
139    bool is_block_file(file_status s) _NOEXCEPT;
140    bool is_block_file(const path& p);
141    bool is_block_file(const path& p, error_code& ec) _NOEXCEPT;
142
143    bool is_character_file(file_status s) _NOEXCEPT;
144    bool is_character_file(const path& p);
145    bool is_character_file(const path& p, error_code& ec) _NOEXCEPT;
146
147    bool is_directory(file_status s) _NOEXCEPT;
148    bool is_directory(const path& p);
149    bool is_directory(const path& p, error_code& ec) _NOEXCEPT;
150
151    bool is_empty(const path& p);
152    bool is_empty(const path& p, error_code& ec) _NOEXCEPT;
153
154    bool is_fifo(file_status s) _NOEXCEPT;
155    bool is_fifo(const path& p);
156    bool is_fifo(const path& p, error_code& ec) _NOEXCEPT;
157
158    bool is_other(file_status s) _NOEXCEPT;
159    bool is_other(const path& p);
160    bool is_other(const path& p, error_code& ec) _NOEXCEPT;
161
162    bool is_regular_file(file_status s) _NOEXCEPT;
163    bool is_regular_file(const path& p);
164    bool is_regular_file(const path& p, error_code& ec) _NOEXCEPT;
165
166    bool is_socket(file_status s) _NOEXCEPT;
167    bool is_socket(const path& p);
168    bool is_socket(const path& p, error_code& ec) _NOEXCEPT;
169
170    bool is_symlink(file_status s) _NOEXCEPT;
171    bool is_symlink(const path& p);
172    bool is_symlink(const path& p, error_code& ec) _NOEXCEPT;
173
174    file_time_type  last_write_time(const path& p);
175    file_time_type  last_write_time(const path& p, error_code& ec) _NOEXCEPT;
176    void last_write_time(const path& p, file_time_type new_time);
177    void last_write_time(const path& p, file_time_type new_time,
178                                 error_code& ec) _NOEXCEPT;
179
180    void permissions(const path& p, perms prms);
181    void permissions(const path& p, perms prms, error_code& ec) _NOEXCEPT;
182
183    path read_symlink(const path& p);
184    path read_symlink(const path& p, error_code& ec);
185
186    bool remove(const path& p);
187    bool remove(const path& p, error_code& ec) _NOEXCEPT;
188
189    uintmax_t    remove_all(const path& p);
190    uintmax_t    remove_all(const path& p, error_code& ec) _NOEXCEPT;
191
192    void rename(const path& from, const path& to);
193    void rename(const path& from, const path& to, error_code& ec) _NOEXCEPT;
194
195    void resize_file(const path& p, uintmax_t size);
196    void resize_file(const path& p, uintmax_t size, error_code& ec) _NOEXCEPT;
197
198    space_info   space(const path& p);
199    space_info   space(const path& p, error_code& ec) _NOEXCEPT;
200
201    file_status  status(const path& p);
202    file_status  status(const path& p, error_code& ec) _NOEXCEPT;
203
204    bool status_known(file_status s) _NOEXCEPT;
205
206    file_status  symlink_status(const path& p);
207    file_status  symlink_status(const path& p, error_code& ec) _NOEXCEPT;
208
209    path system_complete(const path& p);
210    path system_complete(const path& p, error_code& ec);
211
212    path temp_directory_path();
213    path temp_directory_path(error_code& ec);
214
215} } } }  // namespaces std::experimental::filesystem::v1
216
217*/
218
219#include <experimental/__config>
220#include <cstddef>
221#include <chrono>
222#include <iterator>
223#include <iosfwd>
224#include <locale>
225#include <memory>
226#include <stack>
227#include <string>
228#include <system_error>
229#include <utility>
230#include <iomanip> // for quoted
231#include <string_view>
232
233#include <__debug>
234
235#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
236#pragma GCC system_header
237#endif
238
239#define __cpp_lib_experimental_filesystem 201406
240
241_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM
242
243typedef chrono::time_point<std::chrono::system_clock>  file_time_type;
244
245struct _LIBCPP_TYPE_VIS space_info
246{
247  uintmax_t capacity;
248  uintmax_t free;
249  uintmax_t available;
250};
251
252enum class _LIBCPP_ENUM_VIS file_type : signed char
253{
254    none       = 0,
255    not_found  = -1,
256    regular    = 1,
257    directory  = 2,
258    symlink    = 3,
259    block      = 4,
260    character  = 5,
261    fifo       = 6,
262    socket     = 7,
263    unknown    = 8
264};
265
266enum class _LIBCPP_ENUM_VIS perms : unsigned
267{
268    none         = 0,
269
270    owner_read   = 0400,
271    owner_write  = 0200,
272    owner_exec   = 0100,
273    owner_all    = 0700,
274
275    group_read   = 040,
276    group_write  = 020,
277    group_exec   = 010,
278    group_all    = 070,
279
280    others_read  = 04,
281    others_write = 02,
282    others_exec  = 01,
283    others_all   = 07,
284
285    all          = 0777,
286
287    set_uid      = 04000,
288    set_gid      = 02000,
289    sticky_bit   = 01000,
290    mask         = 07777,
291    unknown      = 0xFFFF,
292
293    add_perms        = 0x10000,
294    remove_perms     = 0x20000,
295    symlink_nofollow = 0x40000
296};
297
298_LIBCPP_INLINE_VISIBILITY
299inline _LIBCPP_CONSTEXPR perms operator&(perms _LHS, perms _RHS)
300{ return static_cast<perms>(static_cast<unsigned>(_LHS) & static_cast<unsigned>(_RHS)); }
301
302_LIBCPP_INLINE_VISIBILITY
303inline _LIBCPP_CONSTEXPR perms operator|(perms _LHS, perms _RHS)
304{ return static_cast<perms>(static_cast<unsigned>(_LHS) | static_cast<unsigned>(_RHS)); }
305
306_LIBCPP_INLINE_VISIBILITY
307inline _LIBCPP_CONSTEXPR perms operator^(perms _LHS, perms _RHS)
308{ return static_cast<perms>(static_cast<unsigned>(_LHS) ^ static_cast<unsigned>(_RHS)); }
309
310_LIBCPP_INLINE_VISIBILITY
311inline _LIBCPP_CONSTEXPR perms operator~(perms _LHS)
312{ return static_cast<perms>(~static_cast<unsigned>(_LHS)); }
313
314_LIBCPP_INLINE_VISIBILITY
315inline perms& operator&=(perms& _LHS, perms _RHS)
316{ return _LHS = _LHS & _RHS; }
317
318_LIBCPP_INLINE_VISIBILITY
319inline perms& operator|=(perms& _LHS, perms _RHS)
320{ return _LHS = _LHS | _RHS; }
321
322_LIBCPP_INLINE_VISIBILITY
323inline perms& operator^=(perms& _LHS, perms _RHS)
324{ return _LHS = _LHS ^ _RHS; }
325
326enum class _LIBCPP_ENUM_VIS copy_options : unsigned short
327{
328    none               = 0,
329    skip_existing      = 1,
330    overwrite_existing = 2,
331    update_existing    = 4,
332    recursive          = 8,
333    copy_symlinks      = 16,
334    skip_symlinks      = 32,
335    directories_only   = 64,
336    create_symlinks    = 128,
337    create_hard_links  = 256,
338    __in_recursive_copy = 512,
339};
340
341_LIBCPP_INLINE_VISIBILITY
342inline _LIBCPP_CONSTEXPR copy_options operator&(copy_options _LHS, copy_options _RHS)
343{ return static_cast<copy_options>(static_cast<unsigned short>(_LHS) & static_cast<unsigned short>(_RHS)); }
344
345_LIBCPP_INLINE_VISIBILITY
346inline _LIBCPP_CONSTEXPR copy_options operator|(copy_options _LHS, copy_options _RHS)
347{ return static_cast<copy_options>(static_cast<unsigned short>(_LHS) | static_cast<unsigned short>(_RHS)); }
348
349_LIBCPP_INLINE_VISIBILITY
350inline _LIBCPP_CONSTEXPR copy_options operator^(copy_options _LHS, copy_options _RHS)
351{ return static_cast<copy_options>(static_cast<unsigned short>(_LHS) ^ static_cast<unsigned short>(_RHS)); }
352
353_LIBCPP_INLINE_VISIBILITY
354inline _LIBCPP_CONSTEXPR copy_options operator~(copy_options _LHS)
355{ return static_cast<copy_options>(~static_cast<unsigned short>(_LHS)); }
356
357_LIBCPP_INLINE_VISIBILITY
358inline copy_options& operator&=(copy_options& _LHS, copy_options _RHS)
359{ return _LHS = _LHS & _RHS; }
360
361_LIBCPP_INLINE_VISIBILITY
362inline copy_options& operator|=(copy_options& _LHS, copy_options _RHS)
363{ return _LHS = _LHS | _RHS; }
364
365_LIBCPP_INLINE_VISIBILITY
366inline copy_options& operator^=(copy_options& _LHS, copy_options _RHS)
367{ return _LHS = _LHS ^ _RHS; }
368
369
370enum class _LIBCPP_ENUM_VIS directory_options : unsigned char
371{
372    none                     = 0,
373    follow_directory_symlink = 1,
374    skip_permission_denied   = 2
375};
376
377_LIBCPP_INLINE_VISIBILITY
378inline _LIBCPP_CONSTEXPR directory_options operator&(directory_options _LHS, directory_options _RHS)
379{ return static_cast<directory_options>(static_cast<unsigned char>(_LHS) & static_cast<unsigned char>(_RHS)); }
380
381_LIBCPP_INLINE_VISIBILITY
382inline _LIBCPP_CONSTEXPR directory_options operator|(directory_options _LHS, directory_options _RHS)
383{ return static_cast<directory_options>(static_cast<unsigned char>(_LHS) | static_cast<unsigned char>(_RHS)); }
384
385_LIBCPP_INLINE_VISIBILITY
386inline _LIBCPP_CONSTEXPR directory_options operator^(directory_options _LHS, directory_options _RHS)
387{ return static_cast<directory_options>(static_cast<unsigned char>(_LHS) ^ static_cast<unsigned char>(_RHS)); }
388
389_LIBCPP_INLINE_VISIBILITY
390inline _LIBCPP_CONSTEXPR directory_options operator~(directory_options _LHS)
391{ return static_cast<directory_options>(~static_cast<unsigned char>(_LHS)); }
392
393_LIBCPP_INLINE_VISIBILITY
394inline directory_options& operator&=(directory_options& _LHS, directory_options _RHS)
395{ return _LHS = _LHS & _RHS; }
396
397_LIBCPP_INLINE_VISIBILITY
398inline directory_options& operator|=(directory_options& _LHS, directory_options _RHS)
399{ return _LHS = _LHS | _RHS; }
400
401_LIBCPP_INLINE_VISIBILITY
402inline directory_options& operator^=(directory_options& _LHS, directory_options _RHS)
403{ return _LHS = _LHS ^ _RHS; }
404
405
406class _LIBCPP_TYPE_VIS file_status
407{
408public:
409    // constructors
410    _LIBCPP_INLINE_VISIBILITY
411    explicit file_status(file_type __ft = file_type::none,
412                         perms __prms   = perms::unknown) _NOEXCEPT
413      : __ft_(__ft), __prms_(__prms)
414    {}
415
416    file_status(const file_status&) _NOEXCEPT = default;
417    file_status(file_status&&) _NOEXCEPT = default;
418
419    _LIBCPP_INLINE_VISIBILITY
420    ~file_status() {}
421
422    file_status& operator=(const file_status&) _NOEXCEPT = default;
423    file_status& operator=(file_status&&) _NOEXCEPT = default;
424
425    // observers
426    _LIBCPP_ALWAYS_INLINE
427    file_type type() const _NOEXCEPT {
428        return __ft_;
429    }
430
431    _LIBCPP_ALWAYS_INLINE
432    perms permissions() const _NOEXCEPT {
433        return __prms_;
434    }
435
436    // modifiers
437    _LIBCPP_ALWAYS_INLINE
438    void type(file_type __ft) _NOEXCEPT {
439        __ft_ = __ft;
440    }
441
442    _LIBCPP_ALWAYS_INLINE
443    void permissions(perms __p) _NOEXCEPT {
444        __prms_ = __p;
445    }
446private:
447    file_type __ft_;
448    perms __prms_;
449};
450
451class _LIBCPP_TYPE_VIS directory_entry;
452
453template <class _Tp> struct __can_convert_char {
454  static const bool value = false;
455};
456template <class _Tp> struct __can_convert_char<const _Tp>
457    : public __can_convert_char<_Tp> {
458};
459template <> struct __can_convert_char<char> {
460    static const bool value = true;
461    using __char_type = char;
462};
463template <> struct __can_convert_char<wchar_t>  {
464    static const bool value = true;
465    using __char_type = wchar_t;
466};
467template <> struct __can_convert_char<char16_t> {
468    static const bool value = true;
469    using __char_type = char16_t;
470};
471template <> struct __can_convert_char<char32_t> {
472    static const bool value = true;
473    using __char_type = char32_t;
474};
475
476template <class _ECharT>
477typename enable_if<__can_convert_char<_ECharT>::value, bool>::type
478__is_separator(_ECharT __e) {
479    return __e == _ECharT('/');
480};
481
482struct _NullSentinal {};
483
484template <class _Tp>
485using _Void = void;
486
487template <class _Tp, class = void>
488struct __is_pathable_string : public false_type {};
489
490template <class _ECharT, class _Traits, class _Alloc>
491struct __is_pathable_string<basic_string<_ECharT, _Traits, _Alloc>,
492                            _Void<typename __can_convert_char<_ECharT>::__char_type>>
493: public __can_convert_char<_ECharT>
494{
495    using _Str = basic_string<_ECharT, _Traits, _Alloc>;
496    using _Base = __can_convert_char<_ECharT>;
497    static _ECharT const* __range_begin(_Str const& __s) { return __s.data(); }
498    static _ECharT const* __range_end(_Str const& __s) { return __s.data() + __s.length(); }
499    static _ECharT __first_or_null(_Str const& __s) {
500        return __s.empty() ? _ECharT{} : __s[0];
501    }
502};
503
504
505template <class _ECharT, class _Traits>
506struct __is_pathable_string<basic_string_view<_ECharT, _Traits>,
507                            _Void<typename __can_convert_char<_ECharT>::__char_type>>
508: public __can_convert_char<_ECharT>
509{
510    using _Str = basic_string_view<_ECharT, _Traits>;
511    using _Base = __can_convert_char<_ECharT>;
512    static _ECharT const* __range_begin(_Str const& __s) { return __s.data(); }
513    static _ECharT const* __range_end(_Str const& __s) { return __s.data() + __s.length(); }
514    static _ECharT __first_or_null(_Str const& __s) {
515        return __s.empty() ? _ECharT{} : __s[0];
516    }
517};
518
519template <class _Source,
520          class _DS = typename decay<_Source>::type,
521          class _UnqualPtrType = typename remove_const<
522              typename remove_pointer<_DS>::type>::type,
523          bool _IsCharPtr = is_pointer<_DS>::value &&
524                            __can_convert_char<_UnqualPtrType>::value
525        >
526struct __is_pathable_char_array : false_type {};
527
528template <class _Source, class _ECharT, class _UPtr>
529struct __is_pathable_char_array<_Source, _ECharT*, _UPtr, true>
530        : __can_convert_char<typename remove_const<_ECharT>::type>
531{
532  using _Base = __can_convert_char<typename remove_const<_ECharT>::type>;
533
534  static _ECharT const* __range_begin(const _ECharT* __b) { return __b; }
535  static _ECharT const* __range_end(const _ECharT* __b)
536  {
537      using _Iter = const _ECharT*;
538      const _ECharT __sentinal = _ECharT{};
539      _Iter __e = __b;
540      for (; *__e != __sentinal; ++__e)
541          ;
542      return __e;
543  }
544
545  static _ECharT __first_or_null(const _ECharT* __b) { return *__b; }
546};
547
548template <class _Iter, bool _IsIt = __is_input_iterator<_Iter>::value, class = void>
549struct __is_pathable_iter : false_type {};
550
551template <class _Iter>
552struct __is_pathable_iter<_Iter, true,
553        _Void<typename __can_convert_char<typename iterator_traits<_Iter>::value_type>::__char_type>>
554        : __can_convert_char<typename iterator_traits<_Iter>::value_type>
555{
556  using _ECharT = typename iterator_traits<_Iter>::value_type;
557  using _Base = __can_convert_char<_ECharT>;
558
559  static _Iter         __range_begin(_Iter __b) { return __b; }
560  static _NullSentinal __range_end(_Iter)       { return _NullSentinal{}; }
561
562  static _ECharT __first_or_null(_Iter __b) { return *__b; }
563};
564
565template <class _Tp, bool _IsStringT =  __is_pathable_string<_Tp>::value,
566                     bool _IsCharIterT = __is_pathable_char_array<_Tp>::value,
567                     bool _IsIterT = !_IsCharIterT && __is_pathable_iter<_Tp>::value
568         >
569struct __is_pathable : false_type {
570  static_assert(!_IsStringT && !_IsCharIterT && !_IsIterT, "Must all be false");
571};
572
573template <class _Tp>
574struct __is_pathable<_Tp, true, false, false> : __is_pathable_string<_Tp> {};
575
576
577template <class _Tp>
578struct __is_pathable<_Tp, false, true, false> : __is_pathable_char_array<_Tp> {};
579
580
581template <class _Tp>
582struct __is_pathable<_Tp, false, false, true> : __is_pathable_iter<_Tp> {};
583
584
585template <class _ECharT>
586struct _PathCVT {
587    static_assert(__can_convert_char<_ECharT>::value, "Char type not convertible");
588
589    typedef __narrow_to_utf8<sizeof(_ECharT)*__CHAR_BIT__> _Narrower;
590
591    static void __append_range(string& __dest, _ECharT const* __b, _ECharT const* __e)  {
592        _Narrower()(back_inserter(__dest), __b, __e);
593    }
594
595    template <class _Iter>
596    static void __append_range(string& __dest, _Iter __b, _Iter __e) {
597        static_assert(!is_same<_Iter, _ECharT*>::value, "Call const overload");
598        if (__b == __e) return;
599        basic_string<_ECharT> __tmp(__b, __e);
600        _Narrower()(back_inserter(__dest), __tmp.data(),
601                    __tmp.data() + __tmp.length());
602    }
603
604    template <class _Iter>
605    static void __append_range(string& __dest, _Iter __b, _NullSentinal) {
606        static_assert(!is_same<_Iter, _ECharT*>::value, "Call const overload");
607        const _ECharT __sentinal = _ECharT{};
608        if (*__b == __sentinal) return;
609        basic_string<_ECharT> __tmp;
610        for (; *__b != __sentinal; ++__b)
611            __tmp.push_back(*__b);
612        _Narrower()(back_inserter(__dest), __tmp.data(),
613                    __tmp.data() + __tmp.length());
614    }
615
616    template <class _Source>
617    static void __append_source(string& __dest, _Source const& __s)
618    {
619        using _Traits = __is_pathable<_Source>;
620        __append_range(__dest, _Traits::__range_begin(__s), _Traits::__range_end(__s));
621    }
622};
623
624template <>
625struct _PathCVT<char> {
626
627    template <class _Iter>
628    static typename enable_if<
629        __is_exactly_input_iterator<_Iter>::value
630    >::type __append_range(string& __dest, _Iter __b, _Iter __e) {
631        for (; __b != __e; ++__b)
632            __dest.push_back(*__b);
633    }
634
635    template <class _Iter>
636    static typename enable_if<
637        __is_forward_iterator<_Iter>::value
638    >::type __append_range(string& __dest, _Iter __b, _Iter __e) {
639        __dest.__append_forward_unsafe(__b, __e);
640    }
641
642    template <class _Iter>
643    static void __append_range(string& __dest, _Iter __b, _NullSentinal) {
644        const char __sentinal = char{};
645        for (; *__b != __sentinal; ++__b)
646            __dest.push_back(*__b);
647    }
648
649    template <class _Source>
650    static void __append_source(string& __dest, _Source const& __s)
651    {
652        using _Traits = __is_pathable<_Source>;
653        __append_range(__dest, _Traits::__range_begin(__s),
654                               _Traits::__range_end(__s));
655    }
656};
657
658
659class _LIBCPP_TYPE_VIS path
660{
661    template <class _SourceOrIter, class _Tp = path&>
662    using _EnableIfPathable = typename
663        enable_if<__is_pathable<_SourceOrIter>::value, _Tp>::type;
664
665    template <class _Tp>
666    using _SourceChar = typename __is_pathable<_Tp>::__char_type;
667
668    template <class _Tp>
669    using _SourceCVT = _PathCVT<_SourceChar<_Tp>>;
670
671public:
672    typedef char value_type;
673    typedef basic_string<value_type> string_type;
674    typedef _VSTD::string_view __string_view;
675    static _LIBCPP_CONSTEXPR value_type preferred_separator = '/';
676
677    // constructors and destructor
678    _LIBCPP_INLINE_VISIBILITY path() _NOEXCEPT {}
679    _LIBCPP_INLINE_VISIBILITY path(const path& __p)      : __pn_(__p.__pn_) {}
680    _LIBCPP_INLINE_VISIBILITY path(path&& __p) _NOEXCEPT : __pn_(_VSTD::move(__p.__pn_)) {}
681
682    _LIBCPP_INLINE_VISIBILITY
683    path(string_type&& __s) _NOEXCEPT : __pn_(_VSTD::move(__s)) {}
684
685    template <
686        class _Source,
687        class = _EnableIfPathable<_Source, void>
688        >
689    path(const _Source& __src) {
690        _SourceCVT<_Source>::__append_source(__pn_, __src);
691    }
692
693    template <class _InputIt>
694    path(_InputIt __first, _InputIt __last) {
695        typedef typename iterator_traits<_InputIt>::value_type _ItVal;
696        _PathCVT<_ItVal>::__append_range(__pn_, __first, __last);
697    }
698
699    // TODO Implement locale conversions.
700    template <class _Source,
701              class = _EnableIfPathable<_Source, void>
702             >
703        path(const _Source& __src, const locale& __loc);
704    template <class _InputIt>
705        path(_InputIt __first, _InputIt _last, const locale& __loc);
706
707    _LIBCPP_INLINE_VISIBILITY
708    ~path() = default;
709
710    // assignments
711    _LIBCPP_INLINE_VISIBILITY
712    path& operator=(const path& __p) {
713        __pn_ = __p.__pn_;
714        return *this;
715    }
716
717    _LIBCPP_INLINE_VISIBILITY
718    path& operator=(path&& __p) _NOEXCEPT {
719        __pn_ = _VSTD::move(__p.__pn_);
720        return *this;
721    }
722
723    _LIBCPP_INLINE_VISIBILITY
724    path& operator=(string_type&& __s) _NOEXCEPT {
725        __pn_ = _VSTD::move(__s);
726        return *this;
727    }
728
729    _LIBCPP_INLINE_VISIBILITY
730    path& assign(string_type&& __s) _NOEXCEPT {
731        __pn_ = _VSTD::move(__s);
732        return *this;
733    }
734
735    template <class _Source>
736    _LIBCPP_INLINE_VISIBILITY
737    _EnableIfPathable<_Source>
738    operator=(const _Source& __src)
739    { return this->assign(__src); }
740
741
742    template <class _Source>
743    _EnableIfPathable<_Source>
744    assign(const _Source& __src) {
745        __pn_.clear();
746        _SourceCVT<_Source>::__append_source(__pn_, __src);
747        return *this;
748    }
749
750    template <class _InputIt>
751    path& assign(_InputIt __first, _InputIt __last) {
752        typedef typename iterator_traits<_InputIt>::value_type _ItVal;
753        __pn_.clear();
754        _PathCVT<_ItVal>::__append_range(__pn_, __first, __last);
755        return *this;
756    }
757
758private:
759    template <class _ECharT>
760    void __append_sep_if_needed(_ECharT __first_or_null) {
761        const _ECharT __null_val = {};
762        bool __append_sep = !empty()                       &&
763                            !__is_separator(__pn_.back())  &&
764                            __first_or_null != __null_val  && // non-empty
765                            !__is_separator(__first_or_null);
766        if (__append_sep)
767            __pn_ += preferred_separator;
768    }
769
770public:
771    // appends
772    path& operator/=(const path& __p) {
773        _LIBCPP_ASSERT(!__p.has_root_name(),
774                      "cannot append to a path with a root name");
775        __append_sep_if_needed(__p.empty() ? char{} : __p.__pn_[0]);
776        __pn_ += __p.native();
777        return *this;
778    }
779
780    template <class _Source>
781    _LIBCPP_INLINE_VISIBILITY
782    _EnableIfPathable<_Source>
783    operator/=(const _Source& __src) {
784        return this->append(__src);
785    }
786
787    template <class _Source>
788    _EnableIfPathable<_Source>
789    append(const _Source& __src) {
790        using _Traits = __is_pathable<_Source>;
791        using _CVT = _PathCVT<_SourceChar<_Source>>;
792        __append_sep_if_needed(_Traits::__first_or_null(__src));
793        _CVT::__append_source(__pn_, __src);
794        return *this;
795    }
796
797    template <class _InputIt>
798    path& append(_InputIt __first, _InputIt __last) {
799        typedef typename iterator_traits<_InputIt>::value_type _ItVal;
800        static_assert(__can_convert_char<_ItVal>::value, "Must convertible");
801        using _CVT = _PathCVT<_ItVal>;
802        if (__first != __last) {
803            __append_sep_if_needed(*__first);
804            _CVT::__append_range(__pn_, __first, __last);
805        }
806        return *this;
807    }
808
809    // concatenation
810    _LIBCPP_INLINE_VISIBILITY
811    path& operator+=(const path& __x) {
812        __pn_ += __x.__pn_;
813        return *this;
814    }
815
816    _LIBCPP_INLINE_VISIBILITY
817    path& operator+=(const string_type& __x) {
818        __pn_ += __x;
819        return *this;
820    }
821
822    _LIBCPP_INLINE_VISIBILITY
823    path& operator+=(__string_view __x) {
824        __pn_ += __x;
825        return *this;
826    }
827
828    _LIBCPP_INLINE_VISIBILITY
829    path& operator+=(const value_type* __x) {
830        __pn_ += __x;
831        return *this;
832    }
833
834    _LIBCPP_INLINE_VISIBILITY
835    path& operator+=(value_type __x) {
836        __pn_ += __x;
837        return *this;
838    }
839
840    template <class _ECharT>
841    typename enable_if<__can_convert_char<_ECharT>::value, path&>::type
842    operator+=(_ECharT __x)
843    {
844        basic_string<_ECharT> __tmp;
845        __tmp += __x;
846        _PathCVT<_ECharT>::__append_source(__pn_, __tmp);
847        return *this;
848    }
849
850    template <class _Source>
851    _EnableIfPathable<_Source>
852    operator+=(const _Source& __x) {
853       return this->concat(__x);
854    }
855
856    template <class _Source>
857    _EnableIfPathable<_Source>
858    concat(const _Source& __x) {
859         _SourceCVT<_Source>::__append_source(__pn_, __x);
860        return *this;
861    }
862
863    template <class _InputIt>
864    path& concat(_InputIt __first, _InputIt __last) {
865        typedef typename iterator_traits<_InputIt>::value_type _ItVal;
866        _PathCVT<_ItVal>::__append_range(__pn_, __first, __last);
867        return *this;
868    }
869
870    // modifiers
871    _LIBCPP_INLINE_VISIBILITY
872    void clear() _NOEXCEPT {
873        __pn_.clear();
874    }
875
876    path& make_preferred() { return *this; }
877
878    _LIBCPP_INLINE_VISIBILITY
879    path& remove_filename() {
880      if (__pn_.size() == __root_path_raw().size())
881        clear();
882      else
883        __pn_ = __parent_path();
884      return *this;
885    }
886
887    path& replace_filename(const path& __replacement) {
888        remove_filename();
889        return (*this /= __replacement);
890    }
891
892    path& replace_extension(const path& __replacement = path());
893
894    _LIBCPP_INLINE_VISIBILITY
895    void  swap(path& __rhs) _NOEXCEPT {
896        __pn_.swap(__rhs.__pn_);
897    }
898
899    // native format observers
900    _LIBCPP_INLINE_VISIBILITY
901    const string_type& native() const _NOEXCEPT {
902        return __pn_;
903    }
904
905    _LIBCPP_INLINE_VISIBILITY
906    const value_type* c_str() const _NOEXCEPT { return __pn_.c_str(); }
907
908    _LIBCPP_INLINE_VISIBILITY operator string_type() const { return __pn_;  }
909
910    template <class _ECharT, class _Traits = char_traits<_ECharT>,
911              class _Allocator = allocator<_ECharT> >
912    basic_string<_ECharT, _Traits, _Allocator>
913    string(const _Allocator& __a = _Allocator()) const {
914        using _CVT = __widen_from_utf8<sizeof(_ECharT)*__CHAR_BIT__>;
915        using _Str = basic_string<_ECharT, _Traits, _Allocator>;
916        _Str __s(__a);
917        __s.reserve(__pn_.size());
918        _CVT()(back_inserter(__s), __pn_.data(), __pn_.data() + __pn_.size());
919        return __s;
920    }
921
922    _LIBCPP_INLINE_VISIBILITY std::string    string()    const { return __pn_; }
923    _LIBCPP_INLINE_VISIBILITY std::wstring   wstring()   const { return string<wchar_t>(); }
924    _LIBCPP_INLINE_VISIBILITY std::string    u8string()  const { return __pn_; }
925    _LIBCPP_INLINE_VISIBILITY std::u16string u16string() const { return string<char16_t>(); }
926    _LIBCPP_INLINE_VISIBILITY std::u32string u32string() const { return string<char32_t>(); }
927
928    // generic format observers
929    template <class _ECharT, class _Traits = char_traits<_ECharT>,
930              class _Allocator = allocator<_ECharT>
931    >
932    basic_string<_ECharT, _Traits, _Allocator>
933    generic_string(const _Allocator& __a = _Allocator()) const {
934        return string<_ECharT, _Traits, _Allocator>(__a);
935    }
936
937    std::string    generic_string()    const { return __pn_; }
938    std::wstring   generic_wstring()   const { return string<wchar_t>(); }
939    std::string    generic_u8string()  const { return __pn_; }
940    std::u16string generic_u16string() const { return string<char16_t>(); }
941    std::u32string generic_u32string() const { return string<char32_t>(); }
942
943private:
944    _LIBCPP_FUNC_VIS int __compare(__string_view) const;
945    _LIBCPP_FUNC_VIS __string_view __root_name() const;
946    _LIBCPP_FUNC_VIS __string_view __root_directory() const;
947    _LIBCPP_FUNC_VIS __string_view __root_path_raw() const;
948    _LIBCPP_FUNC_VIS __string_view __relative_path() const;
949    _LIBCPP_FUNC_VIS __string_view __parent_path() const;
950    _LIBCPP_FUNC_VIS __string_view __filename() const;
951    _LIBCPP_FUNC_VIS __string_view __stem() const;
952    _LIBCPP_FUNC_VIS __string_view __extension() const;
953
954public:
955    // compare
956    _LIBCPP_INLINE_VISIBILITY int compare(const path& __p) const _NOEXCEPT { return __compare(__p.__pn_);}
957    _LIBCPP_INLINE_VISIBILITY int compare(const string_type& __s) const { return __compare(__s); }
958    _LIBCPP_INLINE_VISIBILITY int compare(__string_view __s) const { return __compare(__s); }
959    _LIBCPP_INLINE_VISIBILITY int compare(const value_type* __s) const  { return __compare(__s); }
960
961    // decomposition
962    _LIBCPP_INLINE_VISIBILITY path root_name()      const { return  string_type(__root_name()); }
963    _LIBCPP_INLINE_VISIBILITY path root_directory() const { return  string_type(__root_directory()); }
964    _LIBCPP_INLINE_VISIBILITY path root_path()      const { return root_name().append(string_type(__root_directory())); }
965    _LIBCPP_INLINE_VISIBILITY path relative_path()  const { return string_type(__relative_path()); }
966    _LIBCPP_INLINE_VISIBILITY path parent_path()    const { return string_type(__parent_path()); }
967    _LIBCPP_INLINE_VISIBILITY path filename()       const { return string_type(__filename()); }
968    _LIBCPP_INLINE_VISIBILITY path stem()           const { return string_type(__stem());}
969    _LIBCPP_INLINE_VISIBILITY path extension()      const { return string_type(__extension()); }
970
971    // query
972    _LIBCPP_INLINE_VISIBILITY bool empty() const _NOEXCEPT { return __pn_.empty(); }
973
974    _LIBCPP_INLINE_VISIBILITY bool has_root_name()      const { return !__root_name().empty(); }
975    _LIBCPP_INLINE_VISIBILITY bool has_root_directory() const { return !__root_directory().empty(); }
976    _LIBCPP_INLINE_VISIBILITY bool has_root_path()      const { return !__root_path_raw().empty(); }
977    _LIBCPP_INLINE_VISIBILITY bool has_relative_path()  const { return !__relative_path().empty(); }
978    _LIBCPP_INLINE_VISIBILITY bool has_parent_path()    const { return !__parent_path().empty(); }
979    _LIBCPP_INLINE_VISIBILITY bool has_filename()       const { return !__filename().empty(); }
980    _LIBCPP_INLINE_VISIBILITY bool has_stem()           const { return !__stem().empty(); }
981    _LIBCPP_INLINE_VISIBILITY bool has_extension()      const { return !__extension().empty(); }
982
983    _LIBCPP_INLINE_VISIBILITY bool is_absolute()        const { return has_root_directory(); }
984    _LIBCPP_INLINE_VISIBILITY bool is_relative()        const { return !is_absolute(); }
985
986    // iterators
987    class _LIBCPP_TYPE_VIS iterator;
988    typedef iterator const_iterator;
989
990    _LIBCPP_FUNC_VIS iterator begin() const;
991    _LIBCPP_FUNC_VIS iterator end() const;
992
993private:
994    inline _LIBCPP_INLINE_VISIBILITY
995    path& __assign_view(__string_view const& __s) noexcept { __pn_ = string_type(__s); return *this; }
996    string_type __pn_;
997};
998
999inline _LIBCPP_ALWAYS_INLINE
1000void swap(path& __lhs, path& __rhs) _NOEXCEPT {
1001    __lhs.swap(__rhs);
1002}
1003
1004_LIBCPP_FUNC_VIS
1005size_t hash_value(const path& __p) _NOEXCEPT;
1006
1007inline _LIBCPP_INLINE_VISIBILITY
1008bool operator==(const path& __lhs, const path& __rhs) _NOEXCEPT
1009{ return __lhs.compare(__rhs) == 0; }
1010
1011inline _LIBCPP_INLINE_VISIBILITY
1012bool operator!=(const path& __lhs, const path& __rhs) _NOEXCEPT
1013{ return __lhs.compare(__rhs) != 0; }
1014
1015inline _LIBCPP_INLINE_VISIBILITY
1016bool operator<(const path& __lhs, const path& __rhs) _NOEXCEPT
1017{ return __lhs.compare(__rhs) < 0; }
1018
1019inline _LIBCPP_INLINE_VISIBILITY
1020bool operator<=(const path& __lhs, const path& __rhs) _NOEXCEPT
1021{ return __lhs.compare(__rhs) <= 0; }
1022
1023inline _LIBCPP_INLINE_VISIBILITY
1024bool operator>(const path& __lhs, const path& __rhs) _NOEXCEPT
1025{ return __lhs.compare(__rhs) > 0; }
1026
1027inline _LIBCPP_INLINE_VISIBILITY
1028bool operator>=(const path& __lhs, const path& __rhs) _NOEXCEPT
1029{ return __lhs.compare(__rhs) >= 0; }
1030
1031inline _LIBCPP_INLINE_VISIBILITY
1032path operator/(const path& __lhs, const path& __rhs) {
1033    return path(__lhs) /= __rhs;
1034}
1035
1036template <class _CharT, class _Traits>
1037_LIBCPP_INLINE_VISIBILITY
1038typename enable_if<is_same<_CharT, char>::value &&
1039                   is_same<_Traits, char_traits<char>>::value,
1040                   basic_ostream<_CharT, _Traits>&
1041>::type
1042operator<<(basic_ostream<_CharT, _Traits>& __os, const path& __p) {
1043    __os << std::__quoted(__p.native());
1044    return __os;
1045}
1046
1047template <class _CharT, class _Traits>
1048_LIBCPP_INLINE_VISIBILITY
1049typename enable_if<!is_same<_CharT, char>::value ||
1050                   !is_same<_Traits, char_traits<char>>::value,
1051                   basic_ostream<_CharT, _Traits>&
1052>::type
1053operator<<(basic_ostream<_CharT, _Traits>& __os, const path& __p) {
1054    __os << std::__quoted(__p.string<_CharT, _Traits>());
1055    return __os;
1056}
1057
1058template <class _CharT, class _Traits>
1059_LIBCPP_INLINE_VISIBILITY
1060basic_istream<_CharT, _Traits>&
1061operator>>(basic_istream<_CharT, _Traits>& __is, path& __p)
1062{
1063    basic_string<_CharT, _Traits> __tmp;
1064    __is >> __quoted(__tmp);
1065    __p = __tmp;
1066    return __is;
1067}
1068
1069template <class _Source>
1070_LIBCPP_INLINE_VISIBILITY
1071typename enable_if<__is_pathable<_Source>::value, path>::type
1072u8path(const _Source& __s){
1073    static_assert(is_same<typename __is_pathable<_Source>::__char_type, char>::value,
1074        "u8path(Source const&) requires Source have a character type of type 'char'");
1075    return path(__s);
1076}
1077
1078template <class _InputIt>
1079_LIBCPP_INLINE_VISIBILITY
1080typename enable_if<__is_pathable<_InputIt>::value, path>::type
1081u8path(_InputIt __f, _InputIt __l) {
1082    static_assert(is_same<typename __is_pathable<_InputIt>::__char_type, char>::value,
1083        "u8path(Iter, Iter) requires Iter have a value_type of type 'char'");
1084    return path(__f, __l);
1085}
1086
1087class _LIBCPP_TYPE_VIS path::iterator
1088{
1089public:
1090    typedef bidirectional_iterator_tag iterator_category;
1091    typedef path                       value_type;
1092    typedef std::ptrdiff_t             difference_type;
1093    typedef const path*                pointer;
1094    typedef const path&                reference;
1095public:
1096    _LIBCPP_INLINE_VISIBILITY
1097    iterator() : __stashed_elem_(), __path_ptr_(nullptr),
1098                 __entry_(), __state_(__singular) {}
1099
1100    iterator(const iterator&) = default;
1101    ~iterator() = default;
1102
1103    iterator& operator=(const iterator&) = default;
1104
1105    _LIBCPP_INLINE_VISIBILITY
1106    reference operator*() const {
1107        return __stashed_elem_;
1108    }
1109
1110    _LIBCPP_INLINE_VISIBILITY
1111    pointer operator->() const {
1112        return &__stashed_elem_;
1113    }
1114
1115    _LIBCPP_INLINE_VISIBILITY
1116    iterator& operator++() {
1117        _LIBCPP_ASSERT(__state_ != __singular,
1118                       "attempting to increment a singular iterator");
1119        _LIBCPP_ASSERT(__state_ != __at_end,
1120                      "attempting to increment the end iterator");
1121        return __increment();
1122    }
1123
1124    _LIBCPP_INLINE_VISIBILITY
1125    iterator operator++(int) {
1126        iterator __it(*this);
1127        this->operator++();
1128        return __it;
1129    }
1130
1131    _LIBCPP_INLINE_VISIBILITY
1132    iterator& operator--() {
1133        _LIBCPP_ASSERT(__state_ != __singular,
1134                       "attempting to decrement a singular iterator");
1135        _LIBCPP_ASSERT(__entry_.data() != __path_ptr_->native().data(),
1136                       "attempting to decrement the begin iterator");
1137        return __decrement();
1138    }
1139
1140    _LIBCPP_INLINE_VISIBILITY
1141    iterator operator--(int) {
1142        iterator __it(*this);
1143        this->operator--();
1144        return __it;
1145    }
1146
1147private:
1148    friend class path;
1149
1150    static constexpr unsigned char __singular = 0;
1151    static constexpr unsigned char __at_end = 6;
1152
1153    inline _LIBCPP_INLINE_VISIBILITY
1154    friend bool operator==(const iterator&, const iterator&);
1155
1156    _LIBCPP_FUNC_VIS iterator& __increment();
1157    _LIBCPP_FUNC_VIS iterator& __decrement();
1158
1159    path __stashed_elem_;
1160    const path* __path_ptr_;
1161    path::__string_view __entry_;
1162    unsigned char __state_;
1163};
1164
1165inline _LIBCPP_INLINE_VISIBILITY
1166bool operator==(const path::iterator& __lhs, const path::iterator& __rhs) {
1167    return __lhs.__path_ptr_ == __rhs.__path_ptr_ &&
1168           __lhs.__entry_.data() == __rhs.__entry_.data();
1169}
1170
1171inline _LIBCPP_INLINE_VISIBILITY
1172bool operator!=(const path::iterator& __lhs, const path::iterator& __rhs) {
1173    return !(__lhs == __rhs);
1174}
1175
1176class _LIBCPP_EXCEPTION_ABI filesystem_error : public system_error
1177{
1178public:
1179    _LIBCPP_INLINE_VISIBILITY
1180    filesystem_error(const string& __what, error_code __ec)
1181        : system_error(__ec, __what),
1182          __paths_(make_shared<_Storage>(path(), path()))
1183    {}
1184
1185    _LIBCPP_INLINE_VISIBILITY
1186    filesystem_error(const string& __what, const path& __p1, error_code __ec)
1187        : system_error(__ec, __what),
1188        __paths_(make_shared<_Storage>(__p1, path()))
1189    {}
1190
1191    _LIBCPP_INLINE_VISIBILITY
1192    filesystem_error(const string& __what, const path& __p1, const path& __p2,
1193                     error_code __ec)
1194        : system_error(__ec, __what),
1195          __paths_(make_shared<_Storage>(__p1, __p2))
1196    {}
1197
1198    _LIBCPP_INLINE_VISIBILITY
1199    const path& path1() const _NOEXCEPT {
1200        return __paths_->first;
1201    }
1202
1203    _LIBCPP_INLINE_VISIBILITY
1204    const path& path2() const _NOEXCEPT {
1205        return __paths_->second;
1206    }
1207
1208    _LIBCPP_FUNC_VIS
1209    ~filesystem_error() override; // key function
1210
1211    // TODO(ericwf): Create a custom error message.
1212    //const char* what() const _NOEXCEPT;
1213
1214private:
1215    typedef pair<path, path> _Storage;
1216    shared_ptr<_Storage> __paths_;
1217};
1218
1219template <class... _Args>
1220_LIBCPP_NORETURN inline _LIBCPP_ALWAYS_INLINE
1221#ifndef _LIBCPP_NO_EXCEPTIONS
1222void __throw_filesystem_error(_Args && ...__args)
1223{
1224    throw filesystem_error(std::forward<_Args>(__args)...);
1225}
1226#else
1227void __throw_filesystem_error(_Args&&...)
1228{
1229    _VSTD::abort();
1230}
1231#endif
1232
1233
1234// operational functions
1235
1236_LIBCPP_FUNC_VIS
1237path __canonical(const path&, const path&, error_code *__ec=nullptr);
1238_LIBCPP_FUNC_VIS
1239void __copy(const path& __from, const path& __to, copy_options __opt,
1240        error_code *__ec=nullptr);
1241_LIBCPP_FUNC_VIS
1242bool __copy_file(const path& __from, const path& __to, copy_options __opt,
1243        error_code *__ec=nullptr);
1244_LIBCPP_FUNC_VIS
1245void __copy_symlink(const path& __existing_symlink, const path& __new_symlink,
1246        error_code *__ec=nullptr);
1247_LIBCPP_FUNC_VIS
1248bool __create_directories(const path& p, error_code *ec=nullptr);
1249_LIBCPP_FUNC_VIS
1250bool __create_directory(const path& p, error_code *ec=nullptr);
1251_LIBCPP_FUNC_VIS
1252bool __create_directory(const path& p, const path & attributes,
1253        error_code *ec=nullptr);
1254_LIBCPP_FUNC_VIS
1255void __create_directory_symlink(const path& __to, const path& __new_symlink,
1256        error_code *__ec=nullptr);
1257_LIBCPP_FUNC_VIS
1258void __create_hard_link(const path& __to, const path& __new_hard_link,
1259        error_code *__ec=nullptr);
1260_LIBCPP_FUNC_VIS
1261void __create_symlink(const path& __to, const path& __new_symlink,
1262        error_code *__ec=nullptr);
1263_LIBCPP_FUNC_VIS
1264path __current_path(error_code *__ec=nullptr);
1265_LIBCPP_FUNC_VIS
1266void __current_path(const path&, error_code *__ec=nullptr);
1267_LIBCPP_FUNC_VIS
1268bool __equivalent(const path&, const path&, error_code *__ec=nullptr);
1269_LIBCPP_FUNC_VIS
1270uintmax_t __file_size(const path&, error_code *__ec=nullptr);
1271_LIBCPP_FUNC_VIS
1272uintmax_t __hard_link_count(const path&, error_code *__ec=nullptr);
1273_LIBCPP_FUNC_VIS
1274bool __fs_is_empty(const path& p, error_code *ec=nullptr);
1275_LIBCPP_FUNC_VIS
1276file_time_type __last_write_time(const path& p, error_code *ec=nullptr);
1277_LIBCPP_FUNC_VIS
1278void __last_write_time(const path& p, file_time_type new_time,
1279        error_code *ec=nullptr);
1280_LIBCPP_FUNC_VIS
1281void __permissions(const path& p, perms prms, error_code *ec=nullptr);
1282_LIBCPP_FUNC_VIS
1283path __read_symlink(const path& p, error_code *ec=nullptr);
1284_LIBCPP_FUNC_VIS
1285bool __remove(const path& p, error_code *ec=nullptr);
1286_LIBCPP_FUNC_VIS
1287uintmax_t __remove_all(const path& p, error_code *ec=nullptr);
1288_LIBCPP_FUNC_VIS
1289void __rename(const path& from, const path& to, error_code *ec=nullptr);
1290_LIBCPP_FUNC_VIS
1291void __resize_file(const path& p, uintmax_t size, error_code *ec=nullptr);
1292_LIBCPP_FUNC_VIS
1293space_info __space(const path&, error_code *__ec=nullptr);
1294_LIBCPP_FUNC_VIS
1295file_status __status(const path&, error_code *__ec=nullptr);
1296_LIBCPP_FUNC_VIS
1297file_status __symlink_status(const path&, error_code *__ec=nullptr);
1298_LIBCPP_FUNC_VIS
1299path __system_complete(const path&, error_code *__ec=nullptr);
1300_LIBCPP_FUNC_VIS
1301path __temp_directory_path(error_code *__ec=nullptr);
1302
1303inline _LIBCPP_INLINE_VISIBILITY
1304path current_path() {
1305    return __current_path();
1306}
1307
1308inline _LIBCPP_INLINE_VISIBILITY
1309path current_path(error_code& __ec) {
1310    return __current_path(&__ec);
1311}
1312
1313inline _LIBCPP_INLINE_VISIBILITY
1314void current_path(const path& __p) {
1315    __current_path(__p);
1316}
1317
1318inline _LIBCPP_INLINE_VISIBILITY
1319void current_path(const path& __p, error_code& __ec) _NOEXCEPT {
1320    __current_path(__p, &__ec);
1321}
1322
1323_LIBCPP_FUNC_VIS
1324path absolute(const path&, const path& __p2 = current_path());
1325
1326inline _LIBCPP_INLINE_VISIBILITY
1327path canonical(const path& __p, const path& __base = current_path()) {
1328    return __canonical(__p, __base);
1329}
1330
1331inline _LIBCPP_INLINE_VISIBILITY
1332path canonical(const path& __p, error_code& __ec) {
1333    path __base = __current_path(&__ec);
1334    if (__ec) return {};
1335    return __canonical(__p, __base, &__ec);
1336}
1337
1338inline _LIBCPP_INLINE_VISIBILITY
1339path canonical(const path& __p, const path& __base, error_code& __ec) {
1340    return __canonical(__p, __base, &__ec);
1341}
1342
1343inline _LIBCPP_INLINE_VISIBILITY
1344void copy(const path& __from, const path& __to) {
1345    __copy(__from, __to, copy_options::none);
1346}
1347
1348inline _LIBCPP_INLINE_VISIBILITY
1349void copy(const path& __from, const path& __to, error_code& __ec) _NOEXCEPT {
1350    __copy(__from, __to, copy_options::none, &__ec);
1351}
1352
1353inline _LIBCPP_INLINE_VISIBILITY
1354void copy(const path& __from, const path& __to, copy_options __opt) {
1355    __copy(__from, __to, __opt);
1356}
1357
1358inline _LIBCPP_INLINE_VISIBILITY
1359void copy(const path& __from, const path& __to,
1360          copy_options __opt, error_code& __ec) _NOEXCEPT {
1361    __copy(__from, __to, __opt, &__ec);
1362}
1363
1364inline _LIBCPP_INLINE_VISIBILITY
1365bool copy_file(const path& __from, const path& __to) {
1366    return __copy_file(__from, __to, copy_options::none);
1367}
1368
1369inline _LIBCPP_INLINE_VISIBILITY
1370bool copy_file(const path& __from, const path& __to, error_code& __ec) _NOEXCEPT {
1371    return __copy_file(__from, __to, copy_options::none, &__ec);
1372}
1373
1374inline _LIBCPP_INLINE_VISIBILITY
1375bool copy_file(const path& __from, const path& __to, copy_options __opt) {
1376    return __copy_file(__from, __to, __opt);
1377}
1378
1379inline _LIBCPP_INLINE_VISIBILITY
1380bool copy_file(const path& __from, const path& __to,
1381               copy_options __opt, error_code& __ec) _NOEXCEPT {
1382    return __copy_file(__from, __to, __opt, &__ec);
1383}
1384
1385inline _LIBCPP_INLINE_VISIBILITY
1386void copy_symlink(const path& __existing, const path& __new) {
1387    __copy_symlink(__existing, __new);
1388}
1389
1390inline _LIBCPP_INLINE_VISIBILITY
1391void copy_symlink(const path& __ext, const path& __new, error_code& __ec) _NOEXCEPT {
1392    __copy_symlink(__ext, __new, &__ec);
1393}
1394
1395inline _LIBCPP_INLINE_VISIBILITY
1396bool create_directories(const path& __p) {
1397    return __create_directories(__p);
1398}
1399
1400inline _LIBCPP_INLINE_VISIBILITY
1401bool create_directories(const path& __p, error_code& __ec) _NOEXCEPT {
1402    return __create_directories(__p, &__ec);
1403}
1404
1405inline _LIBCPP_INLINE_VISIBILITY
1406bool create_directory(const path& __p) {
1407    return __create_directory(__p);
1408}
1409
1410inline _LIBCPP_INLINE_VISIBILITY
1411bool create_directory(const path& __p, error_code& __ec) _NOEXCEPT {
1412    return __create_directory(__p, &__ec);
1413}
1414
1415inline _LIBCPP_INLINE_VISIBILITY
1416bool create_directory(const path& __p, const path& __attrs) {
1417    return __create_directory(__p, __attrs);
1418}
1419
1420inline _LIBCPP_INLINE_VISIBILITY
1421bool create_directory(const path& __p, const path& __attrs, error_code& __ec) _NOEXCEPT {
1422    return __create_directory(__p, __attrs, &__ec);
1423}
1424
1425inline _LIBCPP_INLINE_VISIBILITY
1426void create_directory_symlink(const path& __to, const path& __new) {
1427    __create_directory_symlink(__to, __new);
1428}
1429
1430inline _LIBCPP_INLINE_VISIBILITY
1431void create_directory_symlink(const path& __to, const path& __new,
1432                              error_code& __ec) _NOEXCEPT {
1433    __create_directory_symlink(__to, __new, &__ec);
1434}
1435
1436inline _LIBCPP_INLINE_VISIBILITY
1437void create_hard_link(const path& __to, const path& __new) {
1438    __create_hard_link(__to, __new);
1439}
1440
1441inline _LIBCPP_INLINE_VISIBILITY
1442void create_hard_link(const path& __to, const path& __new, error_code& __ec) _NOEXCEPT {
1443    __create_hard_link(__to, __new, &__ec);
1444}
1445
1446inline _LIBCPP_INLINE_VISIBILITY
1447void create_symlink(const path& __to, const path& __new) {
1448    __create_symlink(__to, __new);
1449}
1450
1451inline _LIBCPP_INLINE_VISIBILITY
1452void create_symlink(const path& __to, const path& __new, error_code& __ec) _NOEXCEPT {
1453    return __create_symlink(__to, __new, &__ec);
1454}
1455
1456inline _LIBCPP_INLINE_VISIBILITY
1457bool status_known(file_status __s) _NOEXCEPT {
1458    return __s.type() != file_type::none;
1459}
1460
1461inline _LIBCPP_INLINE_VISIBILITY
1462bool exists(file_status __s) _NOEXCEPT {
1463    return status_known(__s) && __s.type() != file_type::not_found;
1464}
1465
1466inline _LIBCPP_INLINE_VISIBILITY
1467bool exists(const path& __p) {
1468    return exists(__status(__p));
1469}
1470
1471inline _LIBCPP_INLINE_VISIBILITY
1472bool exists(const path& __p, error_code& __ec) _NOEXCEPT {
1473    auto __s = __status(__p, &__ec);
1474    if (status_known(__s)) __ec.clear();
1475    return exists(__s);
1476}
1477
1478inline _LIBCPP_INLINE_VISIBILITY
1479bool equivalent(const path& __p1, const path& __p2) {
1480    return __equivalent(__p1, __p2);
1481}
1482
1483inline _LIBCPP_INLINE_VISIBILITY
1484bool equivalent(const path& __p1, const path& __p2, error_code& __ec) _NOEXCEPT {
1485    return __equivalent(__p1, __p2, &__ec);
1486}
1487
1488inline _LIBCPP_INLINE_VISIBILITY
1489uintmax_t file_size(const path& __p) {
1490    return __file_size(__p);
1491}
1492
1493inline _LIBCPP_INLINE_VISIBILITY
1494uintmax_t file_size(const path& __p, error_code& __ec) _NOEXCEPT {
1495    return __file_size(__p, &__ec);
1496}
1497
1498inline _LIBCPP_INLINE_VISIBILITY
1499uintmax_t hard_link_count(const path& __p) {
1500    return __hard_link_count(__p);
1501}
1502
1503inline _LIBCPP_INLINE_VISIBILITY
1504uintmax_t hard_link_count(const path& __p, error_code& __ec) _NOEXCEPT {
1505    return __hard_link_count(__p, &__ec);
1506}
1507
1508inline _LIBCPP_INLINE_VISIBILITY
1509bool is_block_file(file_status __s) _NOEXCEPT {
1510    return __s.type() == file_type::block;
1511}
1512
1513inline _LIBCPP_INLINE_VISIBILITY
1514bool is_block_file(const path& __p) {
1515    return is_block_file(__status(__p));
1516}
1517
1518inline _LIBCPP_INLINE_VISIBILITY
1519bool is_block_file(const path& __p, error_code& __ec) _NOEXCEPT {
1520    return is_block_file(__status(__p, &__ec));
1521}
1522
1523inline _LIBCPP_INLINE_VISIBILITY
1524bool is_character_file(file_status __s) _NOEXCEPT {
1525    return __s.type() == file_type::character;
1526}
1527
1528inline _LIBCPP_INLINE_VISIBILITY
1529bool is_character_file(const path& __p) {
1530    return is_character_file(__status(__p));
1531}
1532
1533inline _LIBCPP_INLINE_VISIBILITY
1534bool is_character_file(const path& __p, error_code& __ec) _NOEXCEPT {
1535    return is_character_file(__status(__p, &__ec));
1536}
1537
1538inline _LIBCPP_INLINE_VISIBILITY
1539bool is_directory(file_status __s) _NOEXCEPT {
1540    return __s.type() == file_type::directory;
1541}
1542
1543inline _LIBCPP_INLINE_VISIBILITY
1544bool is_directory(const path& __p) {
1545    return is_directory(__status(__p));
1546}
1547
1548inline _LIBCPP_INLINE_VISIBILITY
1549bool is_directory(const path& __p, error_code& __ec) _NOEXCEPT {
1550    return is_directory(__status(__p, &__ec));
1551}
1552
1553inline _LIBCPP_INLINE_VISIBILITY
1554bool is_empty(const path& __p) {
1555    return __fs_is_empty(__p);
1556}
1557
1558inline _LIBCPP_INLINE_VISIBILITY
1559bool is_empty(const path& __p, error_code& __ec) _NOEXCEPT {
1560    return __fs_is_empty(__p, &__ec);
1561}
1562
1563inline _LIBCPP_INLINE_VISIBILITY
1564bool is_fifo(file_status __s) _NOEXCEPT {
1565    return __s.type() == file_type::fifo;
1566}
1567inline _LIBCPP_INLINE_VISIBILITY
1568bool is_fifo(const path& __p) {
1569    return is_fifo(__status(__p));
1570}
1571
1572inline _LIBCPP_INLINE_VISIBILITY
1573bool is_fifo(const path& __p, error_code& __ec) _NOEXCEPT {
1574    return is_fifo(__status(__p, &__ec));
1575}
1576
1577inline _LIBCPP_INLINE_VISIBILITY
1578bool is_regular_file(file_status __s) _NOEXCEPT {
1579    return __s.type() == file_type::regular;
1580}
1581
1582inline _LIBCPP_INLINE_VISIBILITY
1583bool is_regular_file(const path& __p) {
1584    return is_regular_file(__status(__p));
1585}
1586
1587inline _LIBCPP_INLINE_VISIBILITY
1588bool is_regular_file(const path& __p, error_code& __ec) _NOEXCEPT {
1589    return is_regular_file(__status(__p, &__ec));
1590}
1591
1592inline _LIBCPP_INLINE_VISIBILITY
1593bool is_socket(file_status __s) _NOEXCEPT {
1594    return __s.type() == file_type::socket;
1595}
1596
1597inline _LIBCPP_INLINE_VISIBILITY
1598bool is_socket(const path& __p) {
1599    return is_socket(__status(__p));
1600}
1601
1602inline _LIBCPP_INLINE_VISIBILITY
1603bool is_socket(const path& __p, error_code& __ec) _NOEXCEPT {
1604    return is_socket(__status(__p, &__ec));
1605}
1606
1607inline _LIBCPP_INLINE_VISIBILITY
1608bool is_symlink(file_status __s) _NOEXCEPT {
1609    return __s.type() == file_type::symlink;
1610}
1611
1612inline _LIBCPP_INLINE_VISIBILITY
1613bool is_symlink(const path& __p) {
1614    return is_symlink(__symlink_status(__p));
1615}
1616
1617inline _LIBCPP_INLINE_VISIBILITY
1618bool is_symlink(const path& __p, error_code& __ec) _NOEXCEPT {
1619    return is_symlink(__symlink_status(__p, &__ec));
1620}
1621
1622inline _LIBCPP_INLINE_VISIBILITY
1623bool is_other(file_status __s) _NOEXCEPT {
1624    return exists(__s)
1625        && !is_regular_file(__s) && !is_directory(__s) && !is_symlink(__s);
1626}
1627
1628inline _LIBCPP_INLINE_VISIBILITY
1629bool is_other(const path& __p) {
1630    return is_other(__status(__p));
1631}
1632
1633inline _LIBCPP_INLINE_VISIBILITY
1634bool is_other(const path& __p, error_code& __ec) _NOEXCEPT {
1635    return is_other(__status(__p, &__ec));
1636}
1637
1638inline _LIBCPP_INLINE_VISIBILITY
1639file_time_type last_write_time(const path& __p) {
1640    return __last_write_time(__p);
1641}
1642
1643inline _LIBCPP_INLINE_VISIBILITY
1644file_time_type last_write_time(const path& __p, error_code& __ec) _NOEXCEPT {
1645    return __last_write_time(__p, &__ec);
1646}
1647
1648inline _LIBCPP_INLINE_VISIBILITY
1649void last_write_time(const path& __p, file_time_type __t) {
1650    __last_write_time(__p, __t);
1651}
1652
1653inline _LIBCPP_INLINE_VISIBILITY
1654void last_write_time(const path& __p, file_time_type __t, error_code& __ec) _NOEXCEPT {
1655    __last_write_time(__p, __t, &__ec);
1656}
1657
1658inline _LIBCPP_INLINE_VISIBILITY
1659void permissions(const path& __p, perms __prms) {
1660    __permissions(__p, __prms);
1661}
1662
1663inline _LIBCPP_INLINE_VISIBILITY
1664void permissions(const path& __p, perms __prms, error_code& __ec)  {
1665    __permissions(__p, __prms, &__ec);
1666}
1667
1668inline _LIBCPP_INLINE_VISIBILITY
1669path read_symlink(const path& __p) {
1670    return __read_symlink(__p);
1671}
1672
1673inline _LIBCPP_INLINE_VISIBILITY
1674path read_symlink(const path& __p, error_code& __ec) {
1675    return __read_symlink(__p, &__ec);
1676}
1677
1678inline _LIBCPP_INLINE_VISIBILITY
1679bool remove(const path& __p) {
1680    return __remove(__p);
1681}
1682
1683inline _LIBCPP_INLINE_VISIBILITY
1684bool remove(const path& __p, error_code& __ec) _NOEXCEPT {
1685    return __remove(__p, &__ec);
1686}
1687
1688inline _LIBCPP_INLINE_VISIBILITY
1689uintmax_t remove_all(const path& __p) {
1690    return __remove_all(__p);
1691}
1692
1693inline _LIBCPP_INLINE_VISIBILITY
1694uintmax_t remove_all(const path& __p, error_code& __ec) _NOEXCEPT {
1695    return __remove_all(__p, &__ec);
1696}
1697
1698inline _LIBCPP_INLINE_VISIBILITY
1699void rename(const path& __from, const path& __to) {
1700    return __rename(__from, __to);
1701}
1702
1703inline _LIBCPP_INLINE_VISIBILITY
1704void rename(const path& __from, const path& __to, error_code& __ec) _NOEXCEPT {
1705    return __rename(__from, __to, &__ec);
1706}
1707
1708inline _LIBCPP_INLINE_VISIBILITY
1709void resize_file(const path& __p, uintmax_t __ns) {
1710    return __resize_file(__p, __ns);
1711}
1712
1713inline _LIBCPP_INLINE_VISIBILITY
1714void resize_file(const path& __p, uintmax_t __ns, error_code& __ec) _NOEXCEPT {
1715    return __resize_file(__p, __ns, &__ec);
1716}
1717
1718inline _LIBCPP_INLINE_VISIBILITY
1719space_info space(const path& __p) {
1720    return __space(__p);
1721}
1722
1723inline _LIBCPP_INLINE_VISIBILITY
1724space_info space(const path& __p, error_code& __ec) _NOEXCEPT {
1725    return __space(__p, &__ec);
1726}
1727
1728inline _LIBCPP_INLINE_VISIBILITY
1729file_status status(const path& __p) {
1730    return __status(__p);
1731}
1732
1733inline _LIBCPP_INLINE_VISIBILITY
1734file_status status(const path& __p, error_code& __ec) _NOEXCEPT {
1735    return __status(__p, &__ec);
1736}
1737
1738inline _LIBCPP_INLINE_VISIBILITY
1739file_status symlink_status(const path& __p) {
1740    return __symlink_status(__p);
1741}
1742
1743inline _LIBCPP_INLINE_VISIBILITY
1744file_status symlink_status(const path& __p, error_code& __ec) _NOEXCEPT {
1745    return __symlink_status(__p, &__ec);
1746}
1747
1748inline _LIBCPP_INLINE_VISIBILITY
1749path system_complete(const path& __p) {
1750    return __system_complete(__p);
1751}
1752
1753inline _LIBCPP_INLINE_VISIBILITY
1754path system_complete(const path& __p, error_code& __ec) {
1755    return __system_complete(__p, &__ec);
1756}
1757
1758inline _LIBCPP_INLINE_VISIBILITY
1759path temp_directory_path() {
1760    return __temp_directory_path();
1761}
1762
1763inline _LIBCPP_INLINE_VISIBILITY
1764path temp_directory_path(error_code& __ec) {
1765    return __temp_directory_path(&__ec);
1766}
1767
1768
1769class directory_entry
1770{
1771    typedef _VSTD_FS::path _Path;
1772
1773public:
1774    // constructors and destructors
1775    directory_entry() _NOEXCEPT = default;
1776    directory_entry(directory_entry const&) = default;
1777    directory_entry(directory_entry&&) _NOEXCEPT = default;
1778
1779    _LIBCPP_INLINE_VISIBILITY
1780    explicit directory_entry(_Path const& __p) : __p_(__p) {}
1781
1782    ~directory_entry() {}
1783
1784    directory_entry& operator=(directory_entry const&) = default;
1785    directory_entry& operator=(directory_entry&&) _NOEXCEPT = default;
1786
1787    _LIBCPP_INLINE_VISIBILITY
1788    void assign(_Path const& __p) {
1789        __p_ = __p;
1790    }
1791
1792    _LIBCPP_INLINE_VISIBILITY
1793    void replace_filename(_Path const& __p) {
1794        __p_ = __p_.parent_path() / __p;
1795    }
1796
1797    _LIBCPP_INLINE_VISIBILITY
1798    _Path const& path() const _NOEXCEPT {
1799        return __p_;
1800    }
1801
1802    _LIBCPP_INLINE_VISIBILITY
1803    operator const _Path&() const _NOEXCEPT {
1804        return __p_;
1805    }
1806
1807    _LIBCPP_INLINE_VISIBILITY
1808    file_status status() const {
1809        return _VSTD_FS::status(__p_);
1810    }
1811
1812    _LIBCPP_INLINE_VISIBILITY
1813    file_status status(error_code& __ec) const _NOEXCEPT {
1814        return _VSTD_FS::status(__p_, __ec);
1815    }
1816
1817    _LIBCPP_INLINE_VISIBILITY
1818    file_status symlink_status() const {
1819        return _VSTD_FS::symlink_status(__p_);
1820    }
1821
1822    _LIBCPP_INLINE_VISIBILITY
1823    file_status symlink_status(error_code& __ec) const _NOEXCEPT {
1824        return _VSTD_FS::symlink_status(__p_, __ec);
1825    }
1826
1827    _LIBCPP_INLINE_VISIBILITY
1828    bool operator< (directory_entry const& __rhs) const _NOEXCEPT {
1829        return __p_ < __rhs.__p_;
1830    }
1831
1832    _LIBCPP_INLINE_VISIBILITY
1833    bool operator==(directory_entry const& __rhs) const _NOEXCEPT {
1834        return __p_ == __rhs.__p_;
1835    }
1836
1837    _LIBCPP_INLINE_VISIBILITY
1838    bool operator!=(directory_entry const& __rhs) const _NOEXCEPT {
1839        return __p_ != __rhs.__p_;
1840    }
1841
1842    _LIBCPP_INLINE_VISIBILITY
1843    bool operator<=(directory_entry const& __rhs) const _NOEXCEPT {
1844        return __p_ <= __rhs.__p_;
1845    }
1846
1847    _LIBCPP_INLINE_VISIBILITY
1848    bool operator> (directory_entry const& __rhs) const _NOEXCEPT {
1849        return __p_ > __rhs.__p_;
1850    }
1851
1852    _LIBCPP_INLINE_VISIBILITY
1853    bool operator>=(directory_entry const& __rhs) const _NOEXCEPT {
1854        return __p_ >= __rhs.__p_;
1855    }
1856private:
1857    _Path __p_;
1858};
1859
1860
1861class directory_iterator;
1862class recursive_directory_iterator;
1863class __dir_stream;
1864
1865class __dir_element_proxy {
1866public:
1867
1868    inline _LIBCPP_INLINE_VISIBILITY
1869    directory_entry operator*() { return _VSTD::move(__elem_); }
1870
1871private:
1872    friend class directory_iterator;
1873    friend class recursive_directory_iterator;
1874    explicit __dir_element_proxy(directory_entry const& __e) : __elem_(__e) {}
1875    __dir_element_proxy(__dir_element_proxy&& __o) : __elem_(_VSTD::move(__o.__elem_)) {}
1876    directory_entry __elem_;
1877};
1878
1879class directory_iterator
1880{
1881public:
1882    typedef directory_entry value_type;
1883    typedef ptrdiff_t difference_type;
1884    typedef value_type const* pointer;
1885    typedef value_type const& reference;
1886    typedef input_iterator_tag iterator_category;
1887
1888public:
1889    //ctor & dtor
1890    directory_iterator() _NOEXCEPT
1891    { }
1892
1893    explicit directory_iterator(const path& __p)
1894        : directory_iterator(__p, nullptr)
1895    { }
1896
1897    directory_iterator(const path& __p, directory_options __opts)
1898        : directory_iterator(__p, nullptr, __opts)
1899    { }
1900
1901    directory_iterator(const path& __p, error_code& __ec) _NOEXCEPT
1902        : directory_iterator(__p, &__ec)
1903    { }
1904
1905    directory_iterator(const path& __p, directory_options __opts,
1906                       error_code& __ec) _NOEXCEPT
1907        : directory_iterator(__p, &__ec, __opts)
1908    { }
1909
1910    directory_iterator(const directory_iterator&) = default;
1911    directory_iterator(directory_iterator&&) = default;
1912    directory_iterator& operator=(const directory_iterator&) = default;
1913
1914    directory_iterator& operator=(directory_iterator&& __o) _NOEXCEPT {
1915        // non-default implementation provided to support self-move assign.
1916        if (this != &__o) {
1917            __imp_ = _VSTD::move(__o.__imp_);
1918        }
1919        return *this;
1920    }
1921
1922    ~directory_iterator() = default;
1923
1924    const directory_entry& operator*() const {
1925        _LIBCPP_ASSERT(__imp_, "The end iterator cannot be dereferenced");
1926        return __deref();
1927    }
1928
1929    const directory_entry* operator->() const
1930    { return &**this; }
1931
1932    directory_iterator& operator++()
1933    { return __increment(); }
1934
1935    __dir_element_proxy operator++(int) {
1936        __dir_element_proxy __p(**this);
1937        __increment();
1938        return __p;
1939    }
1940
1941    directory_iterator& increment(error_code& __ec) _NOEXCEPT
1942    { return __increment(&__ec); }
1943
1944private:
1945    inline _LIBCPP_INLINE_VISIBILITY
1946    friend bool operator==(const directory_iterator& __lhs,
1947                           const directory_iterator& __rhs) _NOEXCEPT;
1948
1949    // construct the dir_stream
1950    _LIBCPP_FUNC_VIS
1951    directory_iterator(const path&, error_code *, directory_options = directory_options::none);
1952    _LIBCPP_FUNC_VIS
1953    directory_iterator& __increment(error_code * __ec = nullptr);
1954    _LIBCPP_FUNC_VIS
1955    const directory_entry& __deref() const;
1956
1957private:
1958    shared_ptr<__dir_stream> __imp_;
1959};
1960
1961
1962inline _LIBCPP_INLINE_VISIBILITY
1963bool operator==(const directory_iterator& __lhs,
1964                const directory_iterator& __rhs) _NOEXCEPT {
1965    return __lhs.__imp_ == __rhs.__imp_;
1966}
1967
1968inline _LIBCPP_INLINE_VISIBILITY
1969bool operator!=(const directory_iterator& __lhs,
1970                const directory_iterator& __rhs) _NOEXCEPT {
1971    return !(__lhs == __rhs);
1972}
1973
1974// enable directory_iterator range-based for statements
1975inline _LIBCPP_INLINE_VISIBILITY
1976directory_iterator begin(directory_iterator __iter) _NOEXCEPT {
1977    return __iter;
1978}
1979
1980inline _LIBCPP_INLINE_VISIBILITY
1981directory_iterator end(const directory_iterator&) _NOEXCEPT {
1982    return directory_iterator();
1983}
1984
1985class recursive_directory_iterator {
1986public:
1987    using value_type = directory_entry;
1988    using difference_type = std::ptrdiff_t;
1989    using pointer = directory_entry const *;
1990    using reference = directory_entry const &;
1991    using iterator_category = std::input_iterator_tag;
1992
1993public:
1994    // constructors and destructor
1995    _LIBCPP_INLINE_VISIBILITY
1996    recursive_directory_iterator()  _NOEXCEPT
1997        : __rec_(false)
1998    {}
1999
2000    _LIBCPP_INLINE_VISIBILITY
2001    explicit recursive_directory_iterator(const path& __p,
2002                directory_options __xoptions = directory_options::none)
2003        : recursive_directory_iterator(__p, __xoptions,  nullptr)
2004    { }
2005
2006    _LIBCPP_INLINE_VISIBILITY
2007    recursive_directory_iterator(const path& __p,
2008        directory_options __xoptions, error_code& __ec) _NOEXCEPT
2009        : recursive_directory_iterator(__p, __xoptions, &__ec)
2010    { }
2011
2012    _LIBCPP_INLINE_VISIBILITY
2013    recursive_directory_iterator(const path& __p, error_code& __ec) _NOEXCEPT
2014        : recursive_directory_iterator(__p, directory_options::none,  &__ec)
2015    { }
2016
2017    recursive_directory_iterator(const recursive_directory_iterator&) = default;
2018    recursive_directory_iterator(recursive_directory_iterator&&) = default;
2019
2020    recursive_directory_iterator &
2021    operator=(const recursive_directory_iterator&) = default;
2022
2023    _LIBCPP_INLINE_VISIBILITY
2024    recursive_directory_iterator &
2025    operator=(recursive_directory_iterator&& __o) noexcept {
2026        // non-default implementation provided to support self-move assign.
2027        if (this != &__o) {
2028            __imp_ = _VSTD::move(__o.__imp_);
2029            __rec_ = __o.__rec_;
2030        }
2031        return *this;
2032    }
2033
2034    ~recursive_directory_iterator() = default;
2035
2036    _LIBCPP_INLINE_VISIBILITY
2037    const directory_entry& operator*() const
2038    { return __deref(); }
2039
2040    _LIBCPP_INLINE_VISIBILITY
2041    const directory_entry* operator->() const
2042    { return &__deref(); }
2043
2044    recursive_directory_iterator& operator++()
2045    { return __increment(); }
2046
2047    _LIBCPP_INLINE_VISIBILITY
2048    __dir_element_proxy operator++(int) {
2049        __dir_element_proxy __p(**this);
2050        __increment();
2051        return __p;
2052    }
2053
2054    _LIBCPP_INLINE_VISIBILITY
2055    recursive_directory_iterator& increment(error_code& __ec) _NOEXCEPT
2056    { return __increment(&__ec); }
2057
2058    _LIBCPP_FUNC_VIS directory_options options() const;
2059    _LIBCPP_FUNC_VIS int  depth() const;
2060
2061    _LIBCPP_INLINE_VISIBILITY
2062    void pop() { __pop(); }
2063
2064    _LIBCPP_INLINE_VISIBILITY
2065    void pop(error_code& __ec)
2066    { __pop(&__ec); }
2067
2068    _LIBCPP_INLINE_VISIBILITY
2069    bool recursion_pending() const
2070    { return __rec_; }
2071
2072    _LIBCPP_INLINE_VISIBILITY
2073    void disable_recursion_pending()
2074    { __rec_ = false; }
2075
2076private:
2077    recursive_directory_iterator(const path& __p, directory_options __opt,
2078                                 error_code *__ec);
2079
2080    _LIBCPP_FUNC_VIS
2081    const directory_entry& __deref() const;
2082
2083    _LIBCPP_FUNC_VIS
2084    bool __try_recursion(error_code* __ec);
2085
2086    _LIBCPP_FUNC_VIS
2087    void __advance(error_code* __ec=nullptr);
2088
2089    _LIBCPP_FUNC_VIS
2090    recursive_directory_iterator& __increment(error_code *__ec=nullptr);
2091
2092    _LIBCPP_FUNC_VIS
2093    void __pop(error_code* __ec=nullptr);
2094
2095    inline _LIBCPP_INLINE_VISIBILITY
2096    friend bool operator==(const recursive_directory_iterator&,
2097                           const recursive_directory_iterator&) _NOEXCEPT;
2098
2099    struct __shared_imp;
2100    shared_ptr<__shared_imp> __imp_;
2101    bool __rec_;
2102};                                     // class recursive_directory_iterator
2103
2104
2105inline _LIBCPP_INLINE_VISIBILITY
2106bool operator==(const recursive_directory_iterator& __lhs,
2107                const recursive_directory_iterator& __rhs) _NOEXCEPT
2108{
2109    return __lhs.__imp_ == __rhs.__imp_;
2110}
2111
2112_LIBCPP_INLINE_VISIBILITY
2113inline bool operator!=(const recursive_directory_iterator& __lhs,
2114                        const recursive_directory_iterator& __rhs) _NOEXCEPT
2115{
2116    return !(__lhs == __rhs);
2117}
2118// enable recursive_directory_iterator range-based for statements
2119inline _LIBCPP_INLINE_VISIBILITY
2120recursive_directory_iterator begin(recursive_directory_iterator __iter) _NOEXCEPT {
2121    return __iter;
2122}
2123
2124inline _LIBCPP_INLINE_VISIBILITY
2125recursive_directory_iterator end(const recursive_directory_iterator&) _NOEXCEPT {
2126    return recursive_directory_iterator();
2127}
2128
2129_LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM
2130
2131#endif // _LIBCPP_EXPERIMENTAL_FILESYSTEM
2132