1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include <__config>
10#include <filesystem>
11#include <vector>
12
13#include "error.h"
14#include "path_parser.h"
15
16_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
17
18using detail::ErrorHandler;
19using parser::createView;
20using parser::PathParser;
21using parser::string_view_t;
22
23///////////////////////////////////////////////////////////////////////////////
24// path definitions
25///////////////////////////////////////////////////////////////////////////////
26
27constexpr path::value_type path::preferred_separator;
28
29path& path::replace_extension(path const& replacement) {
30 path p = extension();
31 if (not p.empty()) {
32 __pn_.erase(__pn_.size() - p.native().size());
33 }
34 if (!replacement.empty()) {
35 if (replacement.native()[0] != '.') {
36 __pn_ += PATHSTR(".");
37 }
38 __pn_.append(replacement.__pn_);
39 }
40 return *this;
41}
42
43///////////////////////////////////////////////////////////////////////////////
44// path.decompose
45
46string_view_t path::__root_name() const {
47 auto PP = PathParser::CreateBegin(__pn_);
48 if (PP.State == PathParser::PS_InRootName)
49 return *PP;
50 return {};
51}
52
53string_view_t path::__root_directory() const {
54 auto PP = PathParser::CreateBegin(__pn_);
55 if (PP.State == PathParser::PS_InRootName)
56 ++PP;
57 if (PP.State == PathParser::PS_InRootDir)
58 return *PP;
59 return {};
60}
61
62string_view_t path::__root_path_raw() const {
63 auto PP = PathParser::CreateBegin(__pn_);
64 if (PP.State == PathParser::PS_InRootName) {
65 auto NextCh = PP.peek();
66 if (NextCh && isSeparator(*NextCh)) {
67 ++PP;
68 return createView(__pn_.data(), &PP.RawEntry.back());
69 }
70 return PP.RawEntry;
71 }
72 if (PP.State == PathParser::PS_InRootDir)
73 return *PP;
74 return {};
75}
76
77static bool ConsumeRootName(PathParser* PP) {
78 static_assert(PathParser::PS_BeforeBegin == 1 && PathParser::PS_InRootName == 2, "Values for enums are incorrect");
79 while (PP->State <= PathParser::PS_InRootName)
80 ++(*PP);
81 return PP->State == PathParser::PS_AtEnd;
82}
83
84static bool ConsumeRootDir(PathParser* PP) {
85 static_assert(PathParser::PS_BeforeBegin == 1 && PathParser::PS_InRootName == 2 && PathParser::PS_InRootDir == 3,
86 "Values for enums are incorrect");
87 while (PP->State <= PathParser::PS_InRootDir)
88 ++(*PP);
89 return PP->State == PathParser::PS_AtEnd;
90}
91
92string_view_t path::__relative_path() const {
93 auto PP = PathParser::CreateBegin(__pn_);
94 if (ConsumeRootDir(&PP))
95 return {};
96 return createView(PP.RawEntry.data(), &__pn_.back());
97}
98
99string_view_t path::__parent_path() const {
100 if (empty())
101 return {};
102 // Determine if we have a root path but not a relative path. In that case
103 // return *this.
104 {
105 auto PP = PathParser::CreateBegin(__pn_);
106 if (ConsumeRootDir(&PP))
107 return __pn_;
108 }
109 // Otherwise remove a single element from the end of the path, and return
110 // a string representing that path
111 {
112 auto PP = PathParser::CreateEnd(__pn_);
113 --PP;
114 if (PP.RawEntry.data() == __pn_.data())
115 return {};
116 --PP;
117 return createView(__pn_.data(), &PP.RawEntry.back());
118 }
119}
120
121string_view_t path::__filename() const {
122 if (empty())
123 return {};
124 {
125 PathParser PP = PathParser::CreateBegin(__pn_);
126 if (ConsumeRootDir(&PP))
127 return {};
128 }
129 return *(--PathParser::CreateEnd(__pn_));
130}
131
132string_view_t path::__stem() const { return parser::separate_filename(__filename()).first; }
133
134string_view_t path::__extension() const { return parser::separate_filename(__filename()).second; }
135
136////////////////////////////////////////////////////////////////////////////
137// path.gen
138
139enum PathPartKind : unsigned char { PK_None, PK_RootSep, PK_Filename, PK_Dot, PK_DotDot, PK_TrailingSep };
140
141static PathPartKind ClassifyPathPart(string_view_t Part) {
142 if (Part.empty())
143 return PK_TrailingSep;
144 if (Part == PATHSTR("."))
145 return PK_Dot;
146 if (Part == PATHSTR(".."))
147 return PK_DotDot;
148 if (Part == PATHSTR("/"))
149 return PK_RootSep;
150#if defined(_LIBCPP_WIN32API)
151 if (Part == PATHSTR("\\"))
152 return PK_RootSep;
153#endif
154 return PK_Filename;
155}
156
157path path::lexically_normal() const {
158 if (__pn_.empty())
159 return *this;
160
161 using PartKindPair = pair<string_view_t, PathPartKind>;
162 vector<PartKindPair> Parts;
163 // Guess as to how many elements the path has to avoid reallocating.
164 Parts.reserve(32);
165
166 // Track the total size of the parts as we collect them. This allows the
167 // resulting path to reserve the correct amount of memory.
168 size_t NewPathSize = 0;
169 auto AddPart = [&](PathPartKind K, string_view_t P) {
170 NewPathSize += P.size();
171 Parts.emplace_back(P, K);
172 };
173 auto LastPartKind = [&]() {
174 if (Parts.empty())
175 return PK_None;
176 return Parts.back().second;
177 };
178
179 bool MaybeNeedTrailingSep = false;
180 // Build a stack containing the remaining elements of the path, popping off
181 // elements which occur before a '..' entry.
182 for (auto PP = PathParser::CreateBegin(__pn_); PP; ++PP) {
183 auto Part = *PP;
184 PathPartKind Kind = ClassifyPathPart(Part);
185 switch (Kind) {
186 case PK_Filename:
187 case PK_RootSep: {
188 // Add all non-dot and non-dot-dot elements to the stack of elements.
189 AddPart(Kind, Part);
190 MaybeNeedTrailingSep = false;
191 break;
192 }
193 case PK_DotDot: {
194 // Only push a ".." element if there are no elements preceding the "..",
195 // or if the preceding element is itself "..".
196 auto LastKind = LastPartKind();
197 if (LastKind == PK_Filename) {
198 NewPathSize -= Parts.back().first.size();
199 Parts.pop_back();
200 } else if (LastKind != PK_RootSep)
201 AddPart(PK_DotDot, PATHSTR(".."));
202 MaybeNeedTrailingSep = LastKind == PK_Filename;
203 break;
204 }
205 case PK_Dot:
206 case PK_TrailingSep: {
207 MaybeNeedTrailingSep = true;
208 break;
209 }
210 case PK_None:
211 __libcpp_unreachable();
212 }
213 }
214 // [fs.path.generic]p6.8: If the path is empty, add a dot.
215 if (Parts.empty())
216 return PATHSTR(".");
217
218 // [fs.path.generic]p6.7: If the last filename is dot-dot, remove any
219 // trailing directory-separator.
220 bool NeedTrailingSep = MaybeNeedTrailingSep && LastPartKind() == PK_Filename;
221
222 path Result;
223 Result.__pn_.reserve(Parts.size() + NewPathSize + NeedTrailingSep);
224 for (auto& PK : Parts)
225 Result /= PK.first;
226
227 if (NeedTrailingSep)
228 Result /= PATHSTR("");
229
230 Result.make_preferred();
231 return Result;
232}
233
234static int DetermineLexicalElementCount(PathParser PP) {
235 int Count = 0;
236 for (; PP; ++PP) {
237 auto Elem = *PP;
238 if (Elem == PATHSTR(".."))
239 --Count;
240 else if (Elem != PATHSTR(".") && Elem != PATHSTR(""))
241 ++Count;
242 }
243 return Count;
244}
245
246path path::lexically_relative(const path& base) const {
247 { // perform root-name/root-directory mismatch checks
248 auto PP = PathParser::CreateBegin(__pn_);
249 auto PPBase = PathParser::CreateBegin(base.__pn_);
250 auto CheckIterMismatchAtBase = [&]() {
251 return PP.State != PPBase.State && (PP.inRootPath() || PPBase.inRootPath());
252 };
253 if (PP.inRootName() && PPBase.inRootName()) {
254 if (*PP != *PPBase)
255 return {};
256 } else if (CheckIterMismatchAtBase())
257 return {};
258
259 if (PP.inRootPath())
260 ++PP;
261 if (PPBase.inRootPath())
262 ++PPBase;
263 if (CheckIterMismatchAtBase())
264 return {};
265 }
266
267 // Find the first mismatching element
268 auto PP = PathParser::CreateBegin(__pn_);
269 auto PPBase = PathParser::CreateBegin(base.__pn_);
270 while (PP && PPBase && PP.State == PPBase.State && *PP == *PPBase) {
271 ++PP;
272 ++PPBase;
273 }
274
275 // If there is no mismatch, return ".".
276 if (!PP && !PPBase)
277 return ".";
278
279 // Otherwise, determine the number of elements, 'n', which are not dot or
280 // dot-dot minus the number of dot-dot elements.
281 int ElemCount = DetermineLexicalElementCount(PPBase);
282 if (ElemCount < 0)
283 return {};
284
285 // if n == 0 and (a == end() || a->empty()), returns path("."); otherwise
286 if (ElemCount == 0 && (PP.atEnd() || *PP == PATHSTR("")))
287 return PATHSTR(".");
288
289 // return a path constructed with 'n' dot-dot elements, followed by the
290 // elements of '*this' after the mismatch.
291 path Result;
292 // FIXME: Reserve enough room in Result that it won't have to re-allocate.
293 while (ElemCount--)
294 Result /= PATHSTR("..");
295 for (; PP; ++PP)
296 Result /= *PP;
297 return Result;
298}
299
300////////////////////////////////////////////////////////////////////////////
301// path.comparisons
302static int CompareRootName(PathParser* LHS, PathParser* RHS) {
303 if (!LHS->inRootName() && !RHS->inRootName())
304 return 0;
305
306 auto GetRootName = [](PathParser* Parser) -> string_view_t { return Parser->inRootName() ? **Parser : PATHSTR(""); };
307 int res = GetRootName(LHS).compare(GetRootName(RHS));
308 ConsumeRootName(PP: LHS);
309 ConsumeRootName(PP: RHS);
310 return res;
311}
312
313static int CompareRootDir(PathParser* LHS, PathParser* RHS) {
314 if (!LHS->inRootDir() && RHS->inRootDir())
315 return -1;
316 else if (LHS->inRootDir() && !RHS->inRootDir())
317 return 1;
318 else {
319 ConsumeRootDir(PP: LHS);
320 ConsumeRootDir(PP: RHS);
321 return 0;
322 }
323}
324
325static int CompareRelative(PathParser* LHSPtr, PathParser* RHSPtr) {
326 auto& LHS = *LHSPtr;
327 auto& RHS = *RHSPtr;
328
329 int res;
330 while (LHS && RHS) {
331 if ((res = (*LHS).compare(str: *RHS)) != 0)
332 return res;
333 ++LHS;
334 ++RHS;
335 }
336 return 0;
337}
338
339static int CompareEndState(PathParser* LHS, PathParser* RHS) {
340 if (LHS->atEnd() && !RHS->atEnd())
341 return -1;
342 else if (!LHS->atEnd() && RHS->atEnd())
343 return 1;
344 return 0;
345}
346
347int path::__compare(string_view_t __s) const {
348 auto LHS = PathParser::CreateBegin(__pn_);
349 auto RHS = PathParser::CreateBegin(__s);
350 int res;
351
352 if ((res = CompareRootName(&LHS, &RHS)) != 0)
353 return res;
354
355 if ((res = CompareRootDir(&LHS, &RHS)) != 0)
356 return res;
357
358 if ((res = CompareRelative(&LHS, &RHS)) != 0)
359 return res;
360
361 return CompareEndState(&LHS, &RHS);
362}
363
364////////////////////////////////////////////////////////////////////////////
365// path.nonmembers
366size_t hash_value(const path& __p) noexcept {
367 auto PP = PathParser::CreateBegin(P: __p.native());
368 size_t hash_value = 0;
369 hash<string_view_t> hasher;
370 while (PP) {
371 hash_value = __hash_combine(hash_value, hasher(*PP));
372 ++PP;
373 }
374 return hash_value;
375}
376
377////////////////////////////////////////////////////////////////////////////
378// path.itr
379path::iterator path::begin() const {
380 auto PP = PathParser::CreateBegin(__pn_);
381 iterator it;
382 it.__path_ptr_ = this;
383 it.__state_ = static_cast<path::iterator::_ParserState>(PP.State);
384 it.__entry_ = PP.RawEntry;
385 it.__stashed_elem_.__assign_view(*PP);
386 return it;
387}
388
389path::iterator path::end() const {
390 iterator it{};
391 it.__state_ = path::iterator::_AtEnd;
392 it.__path_ptr_ = this;
393 return it;
394}
395
396path::iterator& path::iterator::__increment() {
397 PathParser PP(__path_ptr_->native(), __entry_, __state_);
398 ++PP;
399 __state_ = static_cast<_ParserState>(PP.State);
400 __entry_ = PP.RawEntry;
401 __stashed_elem_.__assign_view(*PP);
402 return *this;
403}
404
405path::iterator& path::iterator::__decrement() {
406 PathParser PP(__path_ptr_->native(), __entry_, __state_);
407 --PP;
408 __state_ = static_cast<_ParserState>(PP.State);
409 __entry_ = PP.RawEntry;
410 __stashed_elem_.__assign_view(*PP);
411 return *this;
412}
413
414#if defined(_LIBCPP_WIN32API)
415////////////////////////////////////////////////////////////////////////////
416// Windows path conversions
417size_t __wide_to_char(const wstring& str, char* out, size_t outlen) {
418 if (str.empty())
419 return 0;
420 ErrorHandler<size_t> err("__wide_to_char", nullptr);
421 UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
422 BOOL used_default = FALSE;
423 int ret = WideCharToMultiByte(codepage, 0, str.data(), str.size(), out, outlen, nullptr, &used_default);
424 if (ret <= 0 || used_default)
425 return err.report(errc::illegal_byte_sequence);
426 return ret;
427}
428
429size_t __char_to_wide(const string& str, wchar_t* out, size_t outlen) {
430 if (str.empty())
431 return 0;
432 ErrorHandler<size_t> err("__char_to_wide", nullptr);
433 UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
434 int ret = MultiByteToWideChar(codepage, MB_ERR_INVALID_CHARS, str.data(), str.size(), out, outlen);
435 if (ret <= 0)
436 return err.report(errc::illegal_byte_sequence);
437 return ret;
438}
439#endif
440
441_LIBCPP_END_NAMESPACE_FILESYSTEM
442

source code of libcxx/src/filesystem/path.cpp