xref: /freebsd/contrib/llvm-project/llvm/lib/Support/Path.cpp (revision 06e20d1babecec1f45ffda513f55a8db5f1c0f56)
1 //===-- Path.cpp - Implement OS Path Concept ------------------------------===//
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 //  This file implements the operating system Path API.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Support/Path.h"
14 #include "llvm/ADT/ArrayRef.h"
15 #include "llvm/Config/llvm-config.h"
16 #include "llvm/Support/Endian.h"
17 #include "llvm/Support/Errc.h"
18 #include "llvm/Support/ErrorHandling.h"
19 #include "llvm/Support/FileSystem.h"
20 #include "llvm/Support/Process.h"
21 #include "llvm/Support/Signals.h"
22 #include <cctype>
23 #include <cstring>
24 
25 #if !defined(_MSC_VER) && !defined(__MINGW32__)
26 #include <unistd.h>
27 #else
28 #include <io.h>
29 #endif
30 
31 using namespace llvm;
32 using namespace llvm::support::endian;
33 
34 namespace {
35   using llvm::StringRef;
36   using llvm::sys::path::is_separator;
37   using llvm::sys::path::Style;
38 
39   inline Style real_style(Style style) {
40 #ifdef _WIN32
41     return (style == Style::posix) ? Style::posix : Style::windows;
42 #else
43     return (style == Style::windows) ? Style::windows : Style::posix;
44 #endif
45   }
46 
47   inline const char *separators(Style style) {
48     if (real_style(style) == Style::windows)
49       return "\\/";
50     return "/";
51   }
52 
53   inline char preferred_separator(Style style) {
54     if (real_style(style) == Style::windows)
55       return '\\';
56     return '/';
57   }
58 
59   StringRef find_first_component(StringRef path, Style style) {
60     // Look for this first component in the following order.
61     // * empty (in this case we return an empty string)
62     // * either C: or {//,\\}net.
63     // * {/,\}
64     // * {file,directory}name
65 
66     if (path.empty())
67       return path;
68 
69     if (real_style(style) == Style::windows) {
70       // C:
71       if (path.size() >= 2 &&
72           std::isalpha(static_cast<unsigned char>(path[0])) && path[1] == ':')
73         return path.substr(0, 2);
74     }
75 
76     // //net
77     if ((path.size() > 2) && is_separator(path[0], style) &&
78         path[0] == path[1] && !is_separator(path[2], style)) {
79       // Find the next directory separator.
80       size_t end = path.find_first_of(separators(style), 2);
81       return path.substr(0, end);
82     }
83 
84     // {/,\}
85     if (is_separator(path[0], style))
86       return path.substr(0, 1);
87 
88     // * {file,directory}name
89     size_t end = path.find_first_of(separators(style));
90     return path.substr(0, end);
91   }
92 
93   // Returns the first character of the filename in str. For paths ending in
94   // '/', it returns the position of the '/'.
95   size_t filename_pos(StringRef str, Style style) {
96     if (str.size() > 0 && is_separator(str[str.size() - 1], style))
97       return str.size() - 1;
98 
99     size_t pos = str.find_last_of(separators(style), str.size() - 1);
100 
101     if (real_style(style) == Style::windows) {
102       if (pos == StringRef::npos)
103         pos = str.find_last_of(':', str.size() - 2);
104     }
105 
106     if (pos == StringRef::npos || (pos == 1 && is_separator(str[0], style)))
107       return 0;
108 
109     return pos + 1;
110   }
111 
112   // Returns the position of the root directory in str. If there is no root
113   // directory in str, it returns StringRef::npos.
114   size_t root_dir_start(StringRef str, Style style) {
115     // case "c:/"
116     if (real_style(style) == Style::windows) {
117       if (str.size() > 2 && str[1] == ':' && is_separator(str[2], style))
118         return 2;
119     }
120 
121     // case "//net"
122     if (str.size() > 3 && is_separator(str[0], style) && str[0] == str[1] &&
123         !is_separator(str[2], style)) {
124       return str.find_first_of(separators(style), 2);
125     }
126 
127     // case "/"
128     if (str.size() > 0 && is_separator(str[0], style))
129       return 0;
130 
131     return StringRef::npos;
132   }
133 
134   // Returns the position past the end of the "parent path" of path. The parent
135   // path will not end in '/', unless the parent is the root directory. If the
136   // path has no parent, 0 is returned.
137   size_t parent_path_end(StringRef path, Style style) {
138     size_t end_pos = filename_pos(path, style);
139 
140     bool filename_was_sep =
141         path.size() > 0 && is_separator(path[end_pos], style);
142 
143     // Skip separators until we reach root dir (or the start of the string).
144     size_t root_dir_pos = root_dir_start(path, style);
145     while (end_pos > 0 &&
146            (root_dir_pos == StringRef::npos || end_pos > root_dir_pos) &&
147            is_separator(path[end_pos - 1], style))
148       --end_pos;
149 
150     if (end_pos == root_dir_pos && !filename_was_sep) {
151       // We've reached the root dir and the input path was *not* ending in a
152       // sequence of slashes. Include the root dir in the parent path.
153       return root_dir_pos + 1;
154     }
155 
156     // Otherwise, just include before the last slash.
157     return end_pos;
158   }
159 } // end unnamed namespace
160 
161 enum FSEntity {
162   FS_Dir,
163   FS_File,
164   FS_Name
165 };
166 
167 static std::error_code
168 createUniqueEntity(const Twine &Model, int &ResultFD,
169                    SmallVectorImpl<char> &ResultPath, bool MakeAbsolute,
170                    unsigned Mode, FSEntity Type,
171                    sys::fs::OpenFlags Flags = sys::fs::OF_None) {
172 
173   // Limit the number of attempts we make, so that we don't infinite loop. E.g.
174   // "permission denied" could be for a specific file (so we retry with a
175   // different name) or for the whole directory (retry would always fail).
176   // Checking which is racy, so we try a number of times, then give up.
177   std::error_code EC;
178   for (int Retries = 128; Retries > 0; --Retries) {
179     sys::fs::createUniquePath(Model, ResultPath, MakeAbsolute);
180     // Try to open + create the file.
181     switch (Type) {
182     case FS_File: {
183       EC = sys::fs::openFileForReadWrite(Twine(ResultPath.begin()), ResultFD,
184                                          sys::fs::CD_CreateNew, Flags, Mode);
185       if (EC) {
186         // errc::permission_denied happens on Windows when we try to open a file
187         // that has been marked for deletion.
188         if (EC == errc::file_exists || EC == errc::permission_denied)
189           continue;
190         return EC;
191       }
192 
193       return std::error_code();
194     }
195 
196     case FS_Name: {
197       EC = sys::fs::access(ResultPath.begin(), sys::fs::AccessMode::Exist);
198       if (EC == errc::no_such_file_or_directory)
199         return std::error_code();
200       if (EC)
201         return EC;
202       continue;
203     }
204 
205     case FS_Dir: {
206       EC = sys::fs::create_directory(ResultPath.begin(), false);
207       if (EC) {
208         if (EC == errc::file_exists)
209           continue;
210         return EC;
211       }
212       return std::error_code();
213     }
214     }
215     llvm_unreachable("Invalid Type");
216   }
217   return EC;
218 }
219 
220 namespace llvm {
221 namespace sys  {
222 namespace path {
223 
224 const_iterator begin(StringRef path, Style style) {
225   const_iterator i;
226   i.Path      = path;
227   i.Component = find_first_component(path, style);
228   i.Position  = 0;
229   i.S = style;
230   return i;
231 }
232 
233 const_iterator end(StringRef path) {
234   const_iterator i;
235   i.Path      = path;
236   i.Position  = path.size();
237   return i;
238 }
239 
240 const_iterator &const_iterator::operator++() {
241   assert(Position < Path.size() && "Tried to increment past end!");
242 
243   // Increment Position to past the current component
244   Position += Component.size();
245 
246   // Check for end.
247   if (Position == Path.size()) {
248     Component = StringRef();
249     return *this;
250   }
251 
252   // Both POSIX and Windows treat paths that begin with exactly two separators
253   // specially.
254   bool was_net = Component.size() > 2 && is_separator(Component[0], S) &&
255                  Component[1] == Component[0] && !is_separator(Component[2], S);
256 
257   // Handle separators.
258   if (is_separator(Path[Position], S)) {
259     // Root dir.
260     if (was_net ||
261         // c:/
262         (real_style(S) == Style::windows && Component.endswith(":"))) {
263       Component = Path.substr(Position, 1);
264       return *this;
265     }
266 
267     // Skip extra separators.
268     while (Position != Path.size() && is_separator(Path[Position], S)) {
269       ++Position;
270     }
271 
272     // Treat trailing '/' as a '.', unless it is the root dir.
273     if (Position == Path.size() && Component != "/") {
274       --Position;
275       Component = ".";
276       return *this;
277     }
278   }
279 
280   // Find next component.
281   size_t end_pos = Path.find_first_of(separators(S), Position);
282   Component = Path.slice(Position, end_pos);
283 
284   return *this;
285 }
286 
287 bool const_iterator::operator==(const const_iterator &RHS) const {
288   return Path.begin() == RHS.Path.begin() && Position == RHS.Position;
289 }
290 
291 ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
292   return Position - RHS.Position;
293 }
294 
295 reverse_iterator rbegin(StringRef Path, Style style) {
296   reverse_iterator I;
297   I.Path = Path;
298   I.Position = Path.size();
299   I.S = style;
300   ++I;
301   return I;
302 }
303 
304 reverse_iterator rend(StringRef Path) {
305   reverse_iterator I;
306   I.Path = Path;
307   I.Component = Path.substr(0, 0);
308   I.Position = 0;
309   return I;
310 }
311 
312 reverse_iterator &reverse_iterator::operator++() {
313   size_t root_dir_pos = root_dir_start(Path, S);
314 
315   // Skip separators unless it's the root directory.
316   size_t end_pos = Position;
317   while (end_pos > 0 && (end_pos - 1) != root_dir_pos &&
318          is_separator(Path[end_pos - 1], S))
319     --end_pos;
320 
321   // Treat trailing '/' as a '.', unless it is the root dir.
322   if (Position == Path.size() && !Path.empty() &&
323       is_separator(Path.back(), S) &&
324       (root_dir_pos == StringRef::npos || end_pos - 1 > root_dir_pos)) {
325     --Position;
326     Component = ".";
327     return *this;
328   }
329 
330   // Find next separator.
331   size_t start_pos = filename_pos(Path.substr(0, end_pos), S);
332   Component = Path.slice(start_pos, end_pos);
333   Position = start_pos;
334   return *this;
335 }
336 
337 bool reverse_iterator::operator==(const reverse_iterator &RHS) const {
338   return Path.begin() == RHS.Path.begin() && Component == RHS.Component &&
339          Position == RHS.Position;
340 }
341 
342 ptrdiff_t reverse_iterator::operator-(const reverse_iterator &RHS) const {
343   return Position - RHS.Position;
344 }
345 
346 StringRef root_path(StringRef path, Style style) {
347   const_iterator b = begin(path, style), pos = b, e = end(path);
348   if (b != e) {
349     bool has_net =
350         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
351     bool has_drive = (real_style(style) == Style::windows) && b->endswith(":");
352 
353     if (has_net || has_drive) {
354       if ((++pos != e) && is_separator((*pos)[0], style)) {
355         // {C:/,//net/}, so get the first two components.
356         return path.substr(0, b->size() + pos->size());
357       } else {
358         // just {C:,//net}, return the first component.
359         return *b;
360       }
361     }
362 
363     // POSIX style root directory.
364     if (is_separator((*b)[0], style)) {
365       return *b;
366     }
367   }
368 
369   return StringRef();
370 }
371 
372 StringRef root_name(StringRef path, Style style) {
373   const_iterator b = begin(path, style), e = end(path);
374   if (b != e) {
375     bool has_net =
376         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
377     bool has_drive = (real_style(style) == Style::windows) && b->endswith(":");
378 
379     if (has_net || has_drive) {
380       // just {C:,//net}, return the first component.
381       return *b;
382     }
383   }
384 
385   // No path or no name.
386   return StringRef();
387 }
388 
389 StringRef root_directory(StringRef path, Style style) {
390   const_iterator b = begin(path, style), pos = b, e = end(path);
391   if (b != e) {
392     bool has_net =
393         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
394     bool has_drive = (real_style(style) == Style::windows) && b->endswith(":");
395 
396     if ((has_net || has_drive) &&
397         // {C:,//net}, skip to the next component.
398         (++pos != e) && is_separator((*pos)[0], style)) {
399       return *pos;
400     }
401 
402     // POSIX style root directory.
403     if (!has_net && is_separator((*b)[0], style)) {
404       return *b;
405     }
406   }
407 
408   // No path or no root.
409   return StringRef();
410 }
411 
412 StringRef relative_path(StringRef path, Style style) {
413   StringRef root = root_path(path, style);
414   return path.substr(root.size());
415 }
416 
417 void append(SmallVectorImpl<char> &path, Style style, const Twine &a,
418             const Twine &b, const Twine &c, const Twine &d) {
419   SmallString<32> a_storage;
420   SmallString<32> b_storage;
421   SmallString<32> c_storage;
422   SmallString<32> d_storage;
423 
424   SmallVector<StringRef, 4> components;
425   if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
426   if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
427   if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
428   if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
429 
430   for (auto &component : components) {
431     bool path_has_sep =
432         !path.empty() && is_separator(path[path.size() - 1], style);
433     if (path_has_sep) {
434       // Strip separators from beginning of component.
435       size_t loc = component.find_first_not_of(separators(style));
436       StringRef c = component.substr(loc);
437 
438       // Append it.
439       path.append(c.begin(), c.end());
440       continue;
441     }
442 
443     bool component_has_sep =
444         !component.empty() && is_separator(component[0], style);
445     if (!component_has_sep &&
446         !(path.empty() || has_root_name(component, style))) {
447       // Add a separator.
448       path.push_back(preferred_separator(style));
449     }
450 
451     path.append(component.begin(), component.end());
452   }
453 }
454 
455 void append(SmallVectorImpl<char> &path, const Twine &a, const Twine &b,
456             const Twine &c, const Twine &d) {
457   append(path, Style::native, a, b, c, d);
458 }
459 
460 void append(SmallVectorImpl<char> &path, const_iterator begin,
461             const_iterator end, Style style) {
462   for (; begin != end; ++begin)
463     path::append(path, style, *begin);
464 }
465 
466 StringRef parent_path(StringRef path, Style style) {
467   size_t end_pos = parent_path_end(path, style);
468   if (end_pos == StringRef::npos)
469     return StringRef();
470   else
471     return path.substr(0, end_pos);
472 }
473 
474 void remove_filename(SmallVectorImpl<char> &path, Style style) {
475   size_t end_pos = parent_path_end(StringRef(path.begin(), path.size()), style);
476   if (end_pos != StringRef::npos)
477     path.set_size(end_pos);
478 }
479 
480 void replace_extension(SmallVectorImpl<char> &path, const Twine &extension,
481                        Style style) {
482   StringRef p(path.begin(), path.size());
483   SmallString<32> ext_storage;
484   StringRef ext = extension.toStringRef(ext_storage);
485 
486   // Erase existing extension.
487   size_t pos = p.find_last_of('.');
488   if (pos != StringRef::npos && pos >= filename_pos(p, style))
489     path.set_size(pos);
490 
491   // Append '.' if needed.
492   if (ext.size() > 0 && ext[0] != '.')
493     path.push_back('.');
494 
495   // Append extension.
496   path.append(ext.begin(), ext.end());
497 }
498 
499 static bool starts_with(StringRef Path, StringRef Prefix,
500                         Style style = Style::native) {
501   // Windows prefix matching : case and separator insensitive
502   if (real_style(style) == Style::windows) {
503     if (Path.size() < Prefix.size())
504       return false;
505     for (size_t I = 0, E = Prefix.size(); I != E; ++I) {
506       bool SepPath = is_separator(Path[I], style);
507       bool SepPrefix = is_separator(Prefix[I], style);
508       if (SepPath != SepPrefix)
509         return false;
510       if (!SepPath && toLower(Path[I]) != toLower(Prefix[I]))
511         return false;
512     }
513     return true;
514   }
515   return Path.startswith(Prefix);
516 }
517 
518 bool replace_path_prefix(SmallVectorImpl<char> &Path, StringRef OldPrefix,
519                          StringRef NewPrefix, Style style) {
520   if (OldPrefix.empty() && NewPrefix.empty())
521     return false;
522 
523   StringRef OrigPath(Path.begin(), Path.size());
524   if (!starts_with(OrigPath, OldPrefix, style))
525     return false;
526 
527   // If prefixes have the same size we can simply copy the new one over.
528   if (OldPrefix.size() == NewPrefix.size()) {
529     llvm::copy(NewPrefix, Path.begin());
530     return true;
531   }
532 
533   StringRef RelPath = OrigPath.substr(OldPrefix.size());
534   SmallString<256> NewPath;
535   (Twine(NewPrefix) + RelPath).toVector(NewPath);
536   Path.swap(NewPath);
537   return true;
538 }
539 
540 void native(const Twine &path, SmallVectorImpl<char> &result, Style style) {
541   assert((!path.isSingleStringRef() ||
542           path.getSingleStringRef().data() != result.data()) &&
543          "path and result are not allowed to overlap!");
544   // Clear result.
545   result.clear();
546   path.toVector(result);
547   native(result, style);
548 }
549 
550 void native(SmallVectorImpl<char> &Path, Style style) {
551   if (Path.empty())
552     return;
553   if (real_style(style) == Style::windows) {
554     std::replace(Path.begin(), Path.end(), '/', '\\');
555     if (Path[0] == '~' && (Path.size() == 1 || is_separator(Path[1], style))) {
556       SmallString<128> PathHome;
557       home_directory(PathHome);
558       PathHome.append(Path.begin() + 1, Path.end());
559       Path = PathHome;
560     }
561   } else {
562     for (auto PI = Path.begin(), PE = Path.end(); PI < PE; ++PI)
563       if (*PI == '\\')
564         *PI = '/';
565   }
566 }
567 
568 std::string convert_to_slash(StringRef path, Style style) {
569   if (real_style(style) != Style::windows)
570     return std::string(path);
571 
572   std::string s = path.str();
573   std::replace(s.begin(), s.end(), '\\', '/');
574   return s;
575 }
576 
577 StringRef filename(StringRef path, Style style) { return *rbegin(path, style); }
578 
579 StringRef stem(StringRef path, Style style) {
580   StringRef fname = filename(path, style);
581   size_t pos = fname.find_last_of('.');
582   if (pos == StringRef::npos)
583     return fname;
584   else
585     if ((fname.size() == 1 && fname == ".") ||
586         (fname.size() == 2 && fname == ".."))
587       return fname;
588     else
589       return fname.substr(0, pos);
590 }
591 
592 StringRef extension(StringRef path, Style style) {
593   StringRef fname = filename(path, style);
594   size_t pos = fname.find_last_of('.');
595   if (pos == StringRef::npos)
596     return StringRef();
597   else
598     if ((fname.size() == 1 && fname == ".") ||
599         (fname.size() == 2 && fname == ".."))
600       return StringRef();
601     else
602       return fname.substr(pos);
603 }
604 
605 bool is_separator(char value, Style style) {
606   if (value == '/')
607     return true;
608   if (real_style(style) == Style::windows)
609     return value == '\\';
610   return false;
611 }
612 
613 StringRef get_separator(Style style) {
614   if (real_style(style) == Style::windows)
615     return "\\";
616   return "/";
617 }
618 
619 bool has_root_name(const Twine &path, Style style) {
620   SmallString<128> path_storage;
621   StringRef p = path.toStringRef(path_storage);
622 
623   return !root_name(p, style).empty();
624 }
625 
626 bool has_root_directory(const Twine &path, Style style) {
627   SmallString<128> path_storage;
628   StringRef p = path.toStringRef(path_storage);
629 
630   return !root_directory(p, style).empty();
631 }
632 
633 bool has_root_path(const Twine &path, Style style) {
634   SmallString<128> path_storage;
635   StringRef p = path.toStringRef(path_storage);
636 
637   return !root_path(p, style).empty();
638 }
639 
640 bool has_relative_path(const Twine &path, Style style) {
641   SmallString<128> path_storage;
642   StringRef p = path.toStringRef(path_storage);
643 
644   return !relative_path(p, style).empty();
645 }
646 
647 bool has_filename(const Twine &path, Style style) {
648   SmallString<128> path_storage;
649   StringRef p = path.toStringRef(path_storage);
650 
651   return !filename(p, style).empty();
652 }
653 
654 bool has_parent_path(const Twine &path, Style style) {
655   SmallString<128> path_storage;
656   StringRef p = path.toStringRef(path_storage);
657 
658   return !parent_path(p, style).empty();
659 }
660 
661 bool has_stem(const Twine &path, Style style) {
662   SmallString<128> path_storage;
663   StringRef p = path.toStringRef(path_storage);
664 
665   return !stem(p, style).empty();
666 }
667 
668 bool has_extension(const Twine &path, Style style) {
669   SmallString<128> path_storage;
670   StringRef p = path.toStringRef(path_storage);
671 
672   return !extension(p, style).empty();
673 }
674 
675 bool is_absolute(const Twine &path, Style style) {
676   SmallString<128> path_storage;
677   StringRef p = path.toStringRef(path_storage);
678 
679   bool rootDir = has_root_directory(p, style);
680   bool rootName =
681       (real_style(style) != Style::windows) || has_root_name(p, style);
682 
683   return rootDir && rootName;
684 }
685 
686 bool is_relative(const Twine &path, Style style) {
687   return !is_absolute(path, style);
688 }
689 
690 StringRef remove_leading_dotslash(StringRef Path, Style style) {
691   // Remove leading "./" (or ".//" or "././" etc.)
692   while (Path.size() > 2 && Path[0] == '.' && is_separator(Path[1], style)) {
693     Path = Path.substr(2);
694     while (Path.size() > 0 && is_separator(Path[0], style))
695       Path = Path.substr(1);
696   }
697   return Path;
698 }
699 
700 // Remove path traversal components ("." and "..") when possible, and
701 // canonicalize slashes.
702 bool remove_dots(SmallVectorImpl<char> &the_path, bool remove_dot_dot,
703                  Style style) {
704   style = real_style(style);
705   StringRef remaining(the_path.data(), the_path.size());
706   bool needs_change = false;
707   SmallVector<StringRef, 16> components;
708 
709   // Consume the root path, if present.
710   StringRef root = path::root_path(remaining, style);
711   bool absolute = !root.empty();
712   if (absolute)
713     remaining = remaining.drop_front(root.size());
714 
715   // Loop over path components manually. This makes it easier to detect
716   // non-preferred slashes and double separators that must be canonicalized.
717   while (!remaining.empty()) {
718     size_t next_slash = remaining.find_first_of(separators(style));
719     if (next_slash == StringRef::npos)
720       next_slash = remaining.size();
721     StringRef component = remaining.take_front(next_slash);
722     remaining = remaining.drop_front(next_slash);
723 
724     // Eat the slash, and check if it is the preferred separator.
725     if (!remaining.empty()) {
726       needs_change |= remaining.front() != preferred_separator(style);
727       remaining = remaining.drop_front();
728       // The path needs to be rewritten if it has a trailing slash.
729       // FIXME: This is emergent behavior that could be removed.
730       needs_change |= remaining.empty();
731     }
732 
733     // Check for path traversal components or double separators.
734     if (component.empty() || component == ".") {
735       needs_change = true;
736     } else if (remove_dot_dot && component == "..") {
737       needs_change = true;
738       // Do not allow ".." to remove the root component. If this is the
739       // beginning of a relative path, keep the ".." component.
740       if (!components.empty() && components.back() != "..") {
741         components.pop_back();
742       } else if (!absolute) {
743         components.push_back(component);
744       }
745     } else {
746       components.push_back(component);
747     }
748   }
749 
750   // Avoid rewriting the path unless we have to.
751   if (!needs_change)
752     return false;
753 
754   SmallString<256> buffer = root;
755   if (!components.empty()) {
756     buffer += components[0];
757     for (StringRef C : makeArrayRef(components).drop_front()) {
758       buffer += preferred_separator(style);
759       buffer += C;
760     }
761   }
762   the_path.swap(buffer);
763   return true;
764 }
765 
766 } // end namespace path
767 
768 namespace fs {
769 
770 std::error_code getUniqueID(const Twine Path, UniqueID &Result) {
771   file_status Status;
772   std::error_code EC = status(Path, Status);
773   if (EC)
774     return EC;
775   Result = Status.getUniqueID();
776   return std::error_code();
777 }
778 
779 void createUniquePath(const Twine &Model, SmallVectorImpl<char> &ResultPath,
780                       bool MakeAbsolute) {
781   SmallString<128> ModelStorage;
782   Model.toVector(ModelStorage);
783 
784   if (MakeAbsolute) {
785     // Make model absolute by prepending a temp directory if it's not already.
786     if (!sys::path::is_absolute(Twine(ModelStorage))) {
787       SmallString<128> TDir;
788       sys::path::system_temp_directory(true, TDir);
789       sys::path::append(TDir, Twine(ModelStorage));
790       ModelStorage.swap(TDir);
791     }
792   }
793 
794   ResultPath = ModelStorage;
795   ResultPath.push_back(0);
796   ResultPath.pop_back();
797 
798   // Replace '%' with random chars.
799   for (unsigned i = 0, e = ModelStorage.size(); i != e; ++i) {
800     if (ModelStorage[i] == '%')
801       ResultPath[i] = "0123456789abcdef"[sys::Process::GetRandomNumber() & 15];
802   }
803 }
804 
805 std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
806                                  SmallVectorImpl<char> &ResultPath,
807                                  unsigned Mode) {
808   return createUniqueEntity(Model, ResultFd, ResultPath, false, Mode, FS_File);
809 }
810 
811 static std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
812                                         SmallVectorImpl<char> &ResultPath,
813                                         unsigned Mode, OpenFlags Flags) {
814   return createUniqueEntity(Model, ResultFd, ResultPath, false, Mode, FS_File,
815                             Flags);
816 }
817 
818 std::error_code createUniqueFile(const Twine &Model,
819                                  SmallVectorImpl<char> &ResultPath,
820                                  unsigned Mode) {
821   int FD;
822   auto EC = createUniqueFile(Model, FD, ResultPath, Mode);
823   if (EC)
824     return EC;
825   // FD is only needed to avoid race conditions. Close it right away.
826   close(FD);
827   return EC;
828 }
829 
830 static std::error_code
831 createTemporaryFile(const Twine &Model, int &ResultFD,
832                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type) {
833   SmallString<128> Storage;
834   StringRef P = Model.toNullTerminatedStringRef(Storage);
835   assert(P.find_first_of(separators(Style::native)) == StringRef::npos &&
836          "Model must be a simple filename.");
837   // Use P.begin() so that createUniqueEntity doesn't need to recreate Storage.
838   return createUniqueEntity(P.begin(), ResultFD, ResultPath, true,
839                             owner_read | owner_write, Type);
840 }
841 
842 static std::error_code
843 createTemporaryFile(const Twine &Prefix, StringRef Suffix, int &ResultFD,
844                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type) {
845   const char *Middle = Suffix.empty() ? "-%%%%%%" : "-%%%%%%.";
846   return createTemporaryFile(Prefix + Middle + Suffix, ResultFD, ResultPath,
847                              Type);
848 }
849 
850 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
851                                     int &ResultFD,
852                                     SmallVectorImpl<char> &ResultPath) {
853   return createTemporaryFile(Prefix, Suffix, ResultFD, ResultPath, FS_File);
854 }
855 
856 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
857                                     SmallVectorImpl<char> &ResultPath) {
858   int FD;
859   auto EC = createTemporaryFile(Prefix, Suffix, FD, ResultPath);
860   if (EC)
861     return EC;
862   // FD is only needed to avoid race conditions. Close it right away.
863   close(FD);
864   return EC;
865 }
866 
867 
868 // This is a mkdtemp with a different pattern. We use createUniqueEntity mostly
869 // for consistency. We should try using mkdtemp.
870 std::error_code createUniqueDirectory(const Twine &Prefix,
871                                       SmallVectorImpl<char> &ResultPath) {
872   int Dummy;
873   return createUniqueEntity(Prefix + "-%%%%%%", Dummy, ResultPath, true, 0,
874                             FS_Dir);
875 }
876 
877 std::error_code
878 getPotentiallyUniqueFileName(const Twine &Model,
879                              SmallVectorImpl<char> &ResultPath) {
880   int Dummy;
881   return createUniqueEntity(Model, Dummy, ResultPath, false, 0, FS_Name);
882 }
883 
884 std::error_code
885 getPotentiallyUniqueTempFileName(const Twine &Prefix, StringRef Suffix,
886                                  SmallVectorImpl<char> &ResultPath) {
887   int Dummy;
888   return createTemporaryFile(Prefix, Suffix, Dummy, ResultPath, FS_Name);
889 }
890 
891 void make_absolute(const Twine &current_directory,
892                    SmallVectorImpl<char> &path) {
893   StringRef p(path.data(), path.size());
894 
895   bool rootDirectory = path::has_root_directory(p);
896   bool rootName = path::has_root_name(p);
897 
898   // Already absolute.
899   if ((rootName || real_style(Style::native) != Style::windows) &&
900       rootDirectory)
901     return;
902 
903   // All of the following conditions will need the current directory.
904   SmallString<128> current_dir;
905   current_directory.toVector(current_dir);
906 
907   // Relative path. Prepend the current directory.
908   if (!rootName && !rootDirectory) {
909     // Append path to the current directory.
910     path::append(current_dir, p);
911     // Set path to the result.
912     path.swap(current_dir);
913     return;
914   }
915 
916   if (!rootName && rootDirectory) {
917     StringRef cdrn = path::root_name(current_dir);
918     SmallString<128> curDirRootName(cdrn.begin(), cdrn.end());
919     path::append(curDirRootName, p);
920     // Set path to the result.
921     path.swap(curDirRootName);
922     return;
923   }
924 
925   if (rootName && !rootDirectory) {
926     StringRef pRootName      = path::root_name(p);
927     StringRef bRootDirectory = path::root_directory(current_dir);
928     StringRef bRelativePath  = path::relative_path(current_dir);
929     StringRef pRelativePath  = path::relative_path(p);
930 
931     SmallString<128> res;
932     path::append(res, pRootName, bRootDirectory, bRelativePath, pRelativePath);
933     path.swap(res);
934     return;
935   }
936 
937   llvm_unreachable("All rootName and rootDirectory combinations should have "
938                    "occurred above!");
939 }
940 
941 std::error_code make_absolute(SmallVectorImpl<char> &path) {
942   if (path::is_absolute(path))
943     return {};
944 
945   SmallString<128> current_dir;
946   if (std::error_code ec = current_path(current_dir))
947     return ec;
948 
949   make_absolute(current_dir, path);
950   return {};
951 }
952 
953 std::error_code create_directories(const Twine &Path, bool IgnoreExisting,
954                                    perms Perms) {
955   SmallString<128> PathStorage;
956   StringRef P = Path.toStringRef(PathStorage);
957 
958   // Be optimistic and try to create the directory
959   std::error_code EC = create_directory(P, IgnoreExisting, Perms);
960   // If we succeeded, or had any error other than the parent not existing, just
961   // return it.
962   if (EC != errc::no_such_file_or_directory)
963     return EC;
964 
965   // We failed because of a no_such_file_or_directory, try to create the
966   // parent.
967   StringRef Parent = path::parent_path(P);
968   if (Parent.empty())
969     return EC;
970 
971   if ((EC = create_directories(Parent, IgnoreExisting, Perms)))
972       return EC;
973 
974   return create_directory(P, IgnoreExisting, Perms);
975 }
976 
977 static std::error_code copy_file_internal(int ReadFD, int WriteFD) {
978   const size_t BufSize = 4096;
979   char *Buf = new char[BufSize];
980   int BytesRead = 0, BytesWritten = 0;
981   for (;;) {
982     BytesRead = read(ReadFD, Buf, BufSize);
983     if (BytesRead <= 0)
984       break;
985     while (BytesRead) {
986       BytesWritten = write(WriteFD, Buf, BytesRead);
987       if (BytesWritten < 0)
988         break;
989       BytesRead -= BytesWritten;
990     }
991     if (BytesWritten < 0)
992       break;
993   }
994   delete[] Buf;
995 
996   if (BytesRead < 0 || BytesWritten < 0)
997     return std::error_code(errno, std::generic_category());
998   return std::error_code();
999 }
1000 
1001 #ifndef __APPLE__
1002 std::error_code copy_file(const Twine &From, const Twine &To) {
1003   int ReadFD, WriteFD;
1004   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1005     return EC;
1006   if (std::error_code EC =
1007           openFileForWrite(To, WriteFD, CD_CreateAlways, OF_None)) {
1008     close(ReadFD);
1009     return EC;
1010   }
1011 
1012   std::error_code EC = copy_file_internal(ReadFD, WriteFD);
1013 
1014   close(ReadFD);
1015   close(WriteFD);
1016 
1017   return EC;
1018 }
1019 #endif
1020 
1021 std::error_code copy_file(const Twine &From, int ToFD) {
1022   int ReadFD;
1023   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1024     return EC;
1025 
1026   std::error_code EC = copy_file_internal(ReadFD, ToFD);
1027 
1028   close(ReadFD);
1029 
1030   return EC;
1031 }
1032 
1033 ErrorOr<MD5::MD5Result> md5_contents(int FD) {
1034   MD5 Hash;
1035 
1036   constexpr size_t BufSize = 4096;
1037   std::vector<uint8_t> Buf(BufSize);
1038   int BytesRead = 0;
1039   for (;;) {
1040     BytesRead = read(FD, Buf.data(), BufSize);
1041     if (BytesRead <= 0)
1042       break;
1043     Hash.update(makeArrayRef(Buf.data(), BytesRead));
1044   }
1045 
1046   if (BytesRead < 0)
1047     return std::error_code(errno, std::generic_category());
1048   MD5::MD5Result Result;
1049   Hash.final(Result);
1050   return Result;
1051 }
1052 
1053 ErrorOr<MD5::MD5Result> md5_contents(const Twine &Path) {
1054   int FD;
1055   if (auto EC = openFileForRead(Path, FD, OF_None))
1056     return EC;
1057 
1058   auto Result = md5_contents(FD);
1059   close(FD);
1060   return Result;
1061 }
1062 
1063 bool exists(const basic_file_status &status) {
1064   return status_known(status) && status.type() != file_type::file_not_found;
1065 }
1066 
1067 bool status_known(const basic_file_status &s) {
1068   return s.type() != file_type::status_error;
1069 }
1070 
1071 file_type get_file_type(const Twine &Path, bool Follow) {
1072   file_status st;
1073   if (status(Path, st, Follow))
1074     return file_type::status_error;
1075   return st.type();
1076 }
1077 
1078 bool is_directory(const basic_file_status &status) {
1079   return status.type() == file_type::directory_file;
1080 }
1081 
1082 std::error_code is_directory(const Twine &path, bool &result) {
1083   file_status st;
1084   if (std::error_code ec = status(path, st))
1085     return ec;
1086   result = is_directory(st);
1087   return std::error_code();
1088 }
1089 
1090 bool is_regular_file(const basic_file_status &status) {
1091   return status.type() == file_type::regular_file;
1092 }
1093 
1094 std::error_code is_regular_file(const Twine &path, bool &result) {
1095   file_status st;
1096   if (std::error_code ec = status(path, st))
1097     return ec;
1098   result = is_regular_file(st);
1099   return std::error_code();
1100 }
1101 
1102 bool is_symlink_file(const basic_file_status &status) {
1103   return status.type() == file_type::symlink_file;
1104 }
1105 
1106 std::error_code is_symlink_file(const Twine &path, bool &result) {
1107   file_status st;
1108   if (std::error_code ec = status(path, st, false))
1109     return ec;
1110   result = is_symlink_file(st);
1111   return std::error_code();
1112 }
1113 
1114 bool is_other(const basic_file_status &status) {
1115   return exists(status) &&
1116          !is_regular_file(status) &&
1117          !is_directory(status);
1118 }
1119 
1120 std::error_code is_other(const Twine &Path, bool &Result) {
1121   file_status FileStatus;
1122   if (std::error_code EC = status(Path, FileStatus))
1123     return EC;
1124   Result = is_other(FileStatus);
1125   return std::error_code();
1126 }
1127 
1128 void directory_entry::replace_filename(const Twine &Filename, file_type Type,
1129                                        basic_file_status Status) {
1130   SmallString<128> PathStr = path::parent_path(Path);
1131   path::append(PathStr, Filename);
1132   this->Path = std::string(PathStr.str());
1133   this->Type = Type;
1134   this->Status = Status;
1135 }
1136 
1137 ErrorOr<perms> getPermissions(const Twine &Path) {
1138   file_status Status;
1139   if (std::error_code EC = status(Path, Status))
1140     return EC;
1141 
1142   return Status.permissions();
1143 }
1144 
1145 } // end namespace fs
1146 } // end namespace sys
1147 } // end namespace llvm
1148 
1149 // Include the truly platform-specific parts.
1150 #if defined(LLVM_ON_UNIX)
1151 #include "Unix/Path.inc"
1152 #endif
1153 #if defined(_WIN32)
1154 #include "Windows/Path.inc"
1155 #endif
1156 
1157 namespace llvm {
1158 namespace sys {
1159 namespace fs {
1160 TempFile::TempFile(StringRef Name, int FD)
1161     : TmpName(std::string(Name)), FD(FD) {}
1162 TempFile::TempFile(TempFile &&Other) { *this = std::move(Other); }
1163 TempFile &TempFile::operator=(TempFile &&Other) {
1164   TmpName = std::move(Other.TmpName);
1165   FD = Other.FD;
1166   Other.Done = true;
1167   Other.FD = -1;
1168   return *this;
1169 }
1170 
1171 TempFile::~TempFile() { assert(Done); }
1172 
1173 Error TempFile::discard() {
1174   Done = true;
1175   if (FD != -1 && close(FD) == -1) {
1176     std::error_code EC = std::error_code(errno, std::generic_category());
1177     return errorCodeToError(EC);
1178   }
1179   FD = -1;
1180 
1181 #ifdef _WIN32
1182   // On windows closing will remove the file.
1183   TmpName = "";
1184   return Error::success();
1185 #else
1186   // Always try to close and remove.
1187   std::error_code RemoveEC;
1188   if (!TmpName.empty()) {
1189     RemoveEC = fs::remove(TmpName);
1190     sys::DontRemoveFileOnSignal(TmpName);
1191     if (!RemoveEC)
1192       TmpName = "";
1193   }
1194   return errorCodeToError(RemoveEC);
1195 #endif
1196 }
1197 
1198 Error TempFile::keep(const Twine &Name) {
1199   assert(!Done);
1200   Done = true;
1201   // Always try to close and rename.
1202 #ifdef _WIN32
1203   // If we can't cancel the delete don't rename.
1204   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1205   std::error_code RenameEC = setDeleteDisposition(H, false);
1206   if (!RenameEC) {
1207     RenameEC = rename_fd(FD, Name);
1208     // If rename failed because it's cross-device, copy instead
1209     if (RenameEC ==
1210       std::error_code(ERROR_NOT_SAME_DEVICE, std::system_category())) {
1211       RenameEC = copy_file(TmpName, Name);
1212       setDeleteDisposition(H, true);
1213     }
1214   }
1215 
1216   // If we can't rename, discard the temporary file.
1217   if (RenameEC)
1218     setDeleteDisposition(H, true);
1219 #else
1220   std::error_code RenameEC = fs::rename(TmpName, Name);
1221   if (RenameEC) {
1222     // If we can't rename, try to copy to work around cross-device link issues.
1223     RenameEC = sys::fs::copy_file(TmpName, Name);
1224     // If we can't rename or copy, discard the temporary file.
1225     if (RenameEC)
1226       remove(TmpName);
1227   }
1228   sys::DontRemoveFileOnSignal(TmpName);
1229 #endif
1230 
1231   if (!RenameEC)
1232     TmpName = "";
1233 
1234   if (close(FD) == -1) {
1235     std::error_code EC(errno, std::generic_category());
1236     return errorCodeToError(EC);
1237   }
1238   FD = -1;
1239 
1240   return errorCodeToError(RenameEC);
1241 }
1242 
1243 Error TempFile::keep() {
1244   assert(!Done);
1245   Done = true;
1246 
1247 #ifdef _WIN32
1248   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1249   if (std::error_code EC = setDeleteDisposition(H, false))
1250     return errorCodeToError(EC);
1251 #else
1252   sys::DontRemoveFileOnSignal(TmpName);
1253 #endif
1254 
1255   TmpName = "";
1256 
1257   if (close(FD) == -1) {
1258     std::error_code EC(errno, std::generic_category());
1259     return errorCodeToError(EC);
1260   }
1261   FD = -1;
1262 
1263   return Error::success();
1264 }
1265 
1266 Expected<TempFile> TempFile::create(const Twine &Model, unsigned Mode) {
1267   int FD;
1268   SmallString<128> ResultPath;
1269   if (std::error_code EC =
1270           createUniqueFile(Model, FD, ResultPath, Mode, OF_Delete))
1271     return errorCodeToError(EC);
1272 
1273   TempFile Ret(ResultPath, FD);
1274 #ifndef _WIN32
1275   if (sys::RemoveFileOnSignal(ResultPath)) {
1276     // Make sure we delete the file when RemoveFileOnSignal fails.
1277     consumeError(Ret.discard());
1278     std::error_code EC(errc::operation_not_permitted);
1279     return errorCodeToError(EC);
1280   }
1281 #endif
1282   return std::move(Ret);
1283 }
1284 }
1285 
1286 } // end namsspace sys
1287 } // end namespace llvm
1288