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/ADT/ScopeExit.h"
16#include "llvm/Config/config.h"
17#include "llvm/Config/llvm-config.h"
18#include "llvm/Support/Endian.h"
19#include "llvm/Support/Errc.h"
20#include "llvm/Support/ErrorHandling.h"
21#include "llvm/Support/FileSystem.h"
22#include "llvm/Support/Process.h"
23#include "llvm/Support/Signals.h"
24#include <cctype>
25
26#if !defined(_MSC_VER) && !defined(__MINGW32__)
27#include <unistd.h>
28#else
29#include <io.h>
30#endif
31
32using namespace llvm;
33using namespace llvm::support::endian;
34
35namespace {
36  using llvm::StringRef;
37  using llvm::sys::path::is_separator;
38  using llvm::sys::path::Style;
39
40  inline Style real_style(Style style) {
41    if (style != Style::native)
42      return style;
43    if (is_style_posix(style))
44      return Style::posix;
45    return LLVM_WINDOWS_PREFER_FORWARD_SLASH ? Style::windows_slash
46                                             : Style::windows_backslash;
47  }
48
49  inline const char *separators(Style style) {
50    if (is_style_windows(style))
51      return "\\/";
52    return "/";
53  }
54
55  inline char preferred_separator(Style style) {
56    if (real_style(style) == Style::windows)
57      return '\\';
58    return '/';
59  }
60
61  StringRef find_first_component(StringRef path, Style style) {
62    // Look for this first component in the following order.
63    // * empty (in this case we return an empty string)
64    // * either C: or {//,\\}net.
65    // * {/,\}
66    // * {file,directory}name
67
68    if (path.empty())
69      return path;
70
71    if (is_style_windows(style)) {
72      // C:
73      if (path.size() >= 2 &&
74          std::isalpha(static_cast<unsigned char>(path[0])) && path[1] == ':')
75        return path.substr(0, 2);
76    }
77
78    // //net
79    if ((path.size() > 2) && is_separator(path[0], style) &&
80        path[0] == path[1] && !is_separator(path[2], style)) {
81      // Find the next directory separator.
82      size_t end = path.find_first_of(separators(style), 2);
83      return path.substr(0, end);
84    }
85
86    // {/,\}
87    if (is_separator(path[0], style))
88      return path.substr(0, 1);
89
90    // * {file,directory}name
91    size_t end = path.find_first_of(separators(style));
92    return path.substr(0, end);
93  }
94
95  // Returns the first character of the filename in str. For paths ending in
96  // '/', it returns the position of the '/'.
97  size_t filename_pos(StringRef str, Style style) {
98    if (str.size() > 0 && is_separator(str[str.size() - 1], style))
99      return str.size() - 1;
100
101    size_t pos = str.find_last_of(separators(style), str.size() - 1);
102
103    if (is_style_windows(style)) {
104      if (pos == StringRef::npos)
105        pos = str.find_last_of(':', str.size() - 2);
106    }
107
108    if (pos == StringRef::npos || (pos == 1 && is_separator(str[0], style)))
109      return 0;
110
111    return pos + 1;
112  }
113
114  // Returns the position of the root directory in str. If there is no root
115  // directory in str, it returns StringRef::npos.
116  size_t root_dir_start(StringRef str, Style style) {
117    // case "c:/"
118    if (is_style_windows(style)) {
119      if (str.size() > 2 && str[1] == ':' && is_separator(str[2], style))
120        return 2;
121    }
122
123    // case "//net"
124    if (str.size() > 3 && is_separator(str[0], style) && str[0] == str[1] &&
125        !is_separator(str[2], style)) {
126      return str.find_first_of(separators(style), 2);
127    }
128
129    // case "/"
130    if (str.size() > 0 && is_separator(str[0], style))
131      return 0;
132
133    return StringRef::npos;
134  }
135
136  // Returns the position past the end of the "parent path" of path. The parent
137  // path will not end in '/', unless the parent is the root directory. If the
138  // path has no parent, 0 is returned.
139  size_t parent_path_end(StringRef path, Style style) {
140    size_t end_pos = filename_pos(path, style);
141
142    bool filename_was_sep =
143        path.size() > 0 && is_separator(path[end_pos], style);
144
145    // Skip separators until we reach root dir (or the start of the string).
146    size_t root_dir_pos = root_dir_start(path, style);
147    while (end_pos > 0 &&
148           (root_dir_pos == StringRef::npos || end_pos > root_dir_pos) &&
149           is_separator(path[end_pos - 1], style))
150      --end_pos;
151
152    if (end_pos == root_dir_pos && !filename_was_sep) {
153      // We've reached the root dir and the input path was *not* ending in a
154      // sequence of slashes. Include the root dir in the parent path.
155      return root_dir_pos + 1;
156    }
157
158    // Otherwise, just include before the last slash.
159    return end_pos;
160  }
161} // end unnamed namespace
162
163enum FSEntity {
164  FS_Dir,
165  FS_File,
166  FS_Name
167};
168
169static std::error_code
170createUniqueEntity(const Twine &Model, int &ResultFD,
171                   SmallVectorImpl<char> &ResultPath, bool MakeAbsolute,
172                   FSEntity Type, sys::fs::OpenFlags Flags = sys::fs::OF_None,
173                   unsigned Mode = 0) {
174
175  // Limit the number of attempts we make, so that we don't infinite loop. E.g.
176  // "permission denied" could be for a specific file (so we retry with a
177  // different name) or for the whole directory (retry would always fail).
178  // Checking which is racy, so we try a number of times, then give up.
179  std::error_code EC;
180  for (int Retries = 128; Retries > 0; --Retries) {
181    sys::fs::createUniquePath(Model, ResultPath, MakeAbsolute);
182    // Try to open + create the file.
183    switch (Type) {
184    case FS_File: {
185      EC = sys::fs::openFileForReadWrite(Twine(ResultPath.begin()), ResultFD,
186                                         sys::fs::CD_CreateNew, Flags, Mode);
187      if (EC) {
188        // errc::permission_denied happens on Windows when we try to open a file
189        // that has been marked for deletion.
190        if (EC == errc::file_exists || EC == errc::permission_denied)
191          continue;
192        return EC;
193      }
194
195      return std::error_code();
196    }
197
198    case FS_Name: {
199      EC = sys::fs::access(ResultPath.begin(), sys::fs::AccessMode::Exist);
200      if (EC == errc::no_such_file_or_directory)
201        return std::error_code();
202      if (EC)
203        return EC;
204      continue;
205    }
206
207    case FS_Dir: {
208      EC = sys::fs::create_directory(ResultPath.begin(), false);
209      if (EC) {
210        if (EC == errc::file_exists)
211          continue;
212        return EC;
213      }
214      return std::error_code();
215    }
216    }
217    llvm_unreachable("Invalid Type");
218  }
219  return EC;
220}
221
222namespace llvm {
223namespace sys  {
224namespace path {
225
226const_iterator begin(StringRef path, Style style) {
227  const_iterator i;
228  i.Path      = path;
229  i.Component = find_first_component(path, style);
230  i.Position  = 0;
231  i.S = style;
232  return i;
233}
234
235const_iterator end(StringRef path) {
236  const_iterator i;
237  i.Path      = path;
238  i.Position  = path.size();
239  return i;
240}
241
242const_iterator &const_iterator::operator++() {
243  assert(Position < Path.size() && "Tried to increment past end!");
244
245  // Increment Position to past the current component
246  Position += Component.size();
247
248  // Check for end.
249  if (Position == Path.size()) {
250    Component = StringRef();
251    return *this;
252  }
253
254  // Both POSIX and Windows treat paths that begin with exactly two separators
255  // specially.
256  bool was_net = Component.size() > 2 && is_separator(Component[0], S) &&
257                 Component[1] == Component[0] && !is_separator(Component[2], S);
258
259  // Handle separators.
260  if (is_separator(Path[Position], S)) {
261    // Root dir.
262    if (was_net ||
263        // c:/
264        (is_style_windows(S) && Component.endswith(":"))) {
265      Component = Path.substr(Position, 1);
266      return *this;
267    }
268
269    // Skip extra separators.
270    while (Position != Path.size() && is_separator(Path[Position], S)) {
271      ++Position;
272    }
273
274    // Treat trailing '/' as a '.', unless it is the root dir.
275    if (Position == Path.size() && Component != "/") {
276      --Position;
277      Component = ".";
278      return *this;
279    }
280  }
281
282  // Find next component.
283  size_t end_pos = Path.find_first_of(separators(S), Position);
284  Component = Path.slice(Position, end_pos);
285
286  return *this;
287}
288
289bool const_iterator::operator==(const const_iterator &RHS) const {
290  return Path.begin() == RHS.Path.begin() && Position == RHS.Position;
291}
292
293ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
294  return Position - RHS.Position;
295}
296
297reverse_iterator rbegin(StringRef Path, Style style) {
298  reverse_iterator I;
299  I.Path = Path;
300  I.Position = Path.size();
301  I.S = style;
302  ++I;
303  return I;
304}
305
306reverse_iterator rend(StringRef Path) {
307  reverse_iterator I;
308  I.Path = Path;
309  I.Component = Path.substr(0, 0);
310  I.Position = 0;
311  return I;
312}
313
314reverse_iterator &reverse_iterator::operator++() {
315  size_t root_dir_pos = root_dir_start(Path, S);
316
317  // Skip separators unless it's the root directory.
318  size_t end_pos = Position;
319  while (end_pos > 0 && (end_pos - 1) != root_dir_pos &&
320         is_separator(Path[end_pos - 1], S))
321    --end_pos;
322
323  // Treat trailing '/' as a '.', unless it is the root dir.
324  if (Position == Path.size() && !Path.empty() &&
325      is_separator(Path.back(), S) &&
326      (root_dir_pos == StringRef::npos || end_pos - 1 > root_dir_pos)) {
327    --Position;
328    Component = ".";
329    return *this;
330  }
331
332  // Find next separator.
333  size_t start_pos = filename_pos(Path.substr(0, end_pos), S);
334  Component = Path.slice(start_pos, end_pos);
335  Position = start_pos;
336  return *this;
337}
338
339bool reverse_iterator::operator==(const reverse_iterator &RHS) const {
340  return Path.begin() == RHS.Path.begin() && Component == RHS.Component &&
341         Position == RHS.Position;
342}
343
344ptrdiff_t reverse_iterator::operator-(const reverse_iterator &RHS) const {
345  return Position - RHS.Position;
346}
347
348StringRef root_path(StringRef path, Style style) {
349  const_iterator b = begin(path, style), pos = b, e = end(path);
350  if (b != e) {
351    bool has_net =
352        b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
353    bool has_drive = is_style_windows(style) && b->endswith(":");
354
355    if (has_net || has_drive) {
356      if ((++pos != e) && is_separator((*pos)[0], style)) {
357        // {C:/,//net/}, so get the first two components.
358        return path.substr(0, b->size() + pos->size());
359      }
360      // just {C:,//net}, return the first component.
361      return *b;
362    }
363
364    // POSIX style root directory.
365    if (is_separator((*b)[0], style)) {
366      return *b;
367    }
368  }
369
370  return StringRef();
371}
372
373StringRef root_name(StringRef path, Style style) {
374  const_iterator b = begin(path, style), e = end(path);
375  if (b != e) {
376    bool has_net =
377        b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
378    bool has_drive = is_style_windows(style) && b->endswith(":");
379
380    if (has_net || has_drive) {
381      // just {C:,//net}, return the first component.
382      return *b;
383    }
384  }
385
386  // No path or no name.
387  return StringRef();
388}
389
390StringRef root_directory(StringRef path, Style style) {
391  const_iterator b = begin(path, style), pos = b, e = end(path);
392  if (b != e) {
393    bool has_net =
394        b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
395    bool has_drive = is_style_windows(style) && b->endswith(":");
396
397    if ((has_net || has_drive) &&
398        // {C:,//net}, skip to the next component.
399        (++pos != e) && is_separator((*pos)[0], style)) {
400      return *pos;
401    }
402
403    // POSIX style root directory.
404    if (!has_net && is_separator((*b)[0], style)) {
405      return *b;
406    }
407  }
408
409  // No path or no root.
410  return StringRef();
411}
412
413StringRef relative_path(StringRef path, Style style) {
414  StringRef root = root_path(path, style);
415  return path.substr(root.size());
416}
417
418void append(SmallVectorImpl<char> &path, Style style, const Twine &a,
419            const Twine &b, const Twine &c, const Twine &d) {
420  SmallString<32> a_storage;
421  SmallString<32> b_storage;
422  SmallString<32> c_storage;
423  SmallString<32> d_storage;
424
425  SmallVector<StringRef, 4> components;
426  if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
427  if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
428  if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
429  if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
430
431  for (auto &component : components) {
432    bool path_has_sep =
433        !path.empty() && is_separator(path[path.size() - 1], style);
434    if (path_has_sep) {
435      // Strip separators from beginning of component.
436      size_t loc = component.find_first_not_of(separators(style));
437      StringRef c = component.substr(loc);
438
439      // Append it.
440      path.append(c.begin(), c.end());
441      continue;
442    }
443
444    bool component_has_sep =
445        !component.empty() && is_separator(component[0], style);
446    if (!component_has_sep &&
447        !(path.empty() || has_root_name(component, style))) {
448      // Add a separator.
449      path.push_back(preferred_separator(style));
450    }
451
452    path.append(component.begin(), component.end());
453  }
454}
455
456void append(SmallVectorImpl<char> &path, const Twine &a, const Twine &b,
457            const Twine &c, const Twine &d) {
458  append(path, Style::native, a, b, c, d);
459}
460
461void append(SmallVectorImpl<char> &path, const_iterator begin,
462            const_iterator end, Style style) {
463  for (; begin != end; ++begin)
464    path::append(path, style, *begin);
465}
466
467StringRef parent_path(StringRef path, Style style) {
468  size_t end_pos = parent_path_end(path, style);
469  if (end_pos == StringRef::npos)
470    return StringRef();
471  return path.substr(0, end_pos);
472}
473
474void 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.truncate(end_pos);
478}
479
480void 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.truncate(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
499static bool starts_with(StringRef Path, StringRef Prefix,
500                        Style style = Style::native) {
501  // Windows prefix matching : case and separator insensitive
502  if (is_style_windows(style)) {
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
518bool 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
540void 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
550void native(SmallVectorImpl<char> &Path, Style style) {
551  if (Path.empty())
552    return;
553  if (is_style_windows(style)) {
554    for (char &Ch : Path)
555      if (is_separator(Ch, style))
556        Ch = preferred_separator(style);
557    if (Path[0] == '~' && (Path.size() == 1 || is_separator(Path[1], style))) {
558      SmallString<128> PathHome;
559      home_directory(PathHome);
560      PathHome.append(Path.begin() + 1, Path.end());
561      Path = PathHome;
562    }
563  } else {
564    std::replace(Path.begin(), Path.end(), '\\', '/');
565  }
566}
567
568std::string convert_to_slash(StringRef path, Style style) {
569  if (is_style_posix(style))
570    return std::string(path);
571
572  std::string s = path.str();
573  std::replace(s.begin(), s.end(), '\\', '/');
574  return s;
575}
576
577StringRef filename(StringRef path, Style style) { return *rbegin(path, style); }
578
579StringRef 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  if ((fname.size() == 1 && fname == ".") ||
585      (fname.size() == 2 && fname == ".."))
586    return fname;
587  return fname.substr(0, pos);
588}
589
590StringRef extension(StringRef path, Style style) {
591  StringRef fname = filename(path, style);
592  size_t pos = fname.find_last_of('.');
593  if (pos == StringRef::npos)
594    return StringRef();
595  if ((fname.size() == 1 && fname == ".") ||
596      (fname.size() == 2 && fname == ".."))
597    return StringRef();
598  return fname.substr(pos);
599}
600
601bool is_separator(char value, Style style) {
602  if (value == '/')
603    return true;
604  if (is_style_windows(style))
605    return value == '\\';
606  return false;
607}
608
609StringRef get_separator(Style style) {
610  if (real_style(style) == Style::windows)
611    return "\\";
612  return "/";
613}
614
615bool has_root_name(const Twine &path, Style style) {
616  SmallString<128> path_storage;
617  StringRef p = path.toStringRef(path_storage);
618
619  return !root_name(p, style).empty();
620}
621
622bool has_root_directory(const Twine &path, Style style) {
623  SmallString<128> path_storage;
624  StringRef p = path.toStringRef(path_storage);
625
626  return !root_directory(p, style).empty();
627}
628
629bool has_root_path(const Twine &path, Style style) {
630  SmallString<128> path_storage;
631  StringRef p = path.toStringRef(path_storage);
632
633  return !root_path(p, style).empty();
634}
635
636bool has_relative_path(const Twine &path, Style style) {
637  SmallString<128> path_storage;
638  StringRef p = path.toStringRef(path_storage);
639
640  return !relative_path(p, style).empty();
641}
642
643bool has_filename(const Twine &path, Style style) {
644  SmallString<128> path_storage;
645  StringRef p = path.toStringRef(path_storage);
646
647  return !filename(p, style).empty();
648}
649
650bool has_parent_path(const Twine &path, Style style) {
651  SmallString<128> path_storage;
652  StringRef p = path.toStringRef(path_storage);
653
654  return !parent_path(p, style).empty();
655}
656
657bool has_stem(const Twine &path, Style style) {
658  SmallString<128> path_storage;
659  StringRef p = path.toStringRef(path_storage);
660
661  return !stem(p, style).empty();
662}
663
664bool has_extension(const Twine &path, Style style) {
665  SmallString<128> path_storage;
666  StringRef p = path.toStringRef(path_storage);
667
668  return !extension(p, style).empty();
669}
670
671bool is_absolute(const Twine &path, Style style) {
672  SmallString<128> path_storage;
673  StringRef p = path.toStringRef(path_storage);
674
675  bool rootDir = has_root_directory(p, style);
676  bool rootName = is_style_posix(style) || has_root_name(p, style);
677
678  return rootDir && rootName;
679}
680
681bool is_absolute_gnu(const Twine &path, Style style) {
682  SmallString<128> path_storage;
683  StringRef p = path.toStringRef(path_storage);
684
685  // Handle '/' which is absolute for both Windows and POSIX systems.
686  // Handle '\\' on Windows.
687  if (!p.empty() && is_separator(p.front(), style))
688    return true;
689
690  if (is_style_windows(style)) {
691    // Handle drive letter pattern (a character followed by ':') on Windows.
692    if (p.size() >= 2 && (p[0] && p[1] == ':'))
693      return true;
694  }
695
696  return false;
697}
698
699bool is_relative(const Twine &path, Style style) {
700  return !is_absolute(path, style);
701}
702
703StringRef remove_leading_dotslash(StringRef Path, Style style) {
704  // Remove leading "./" (or ".//" or "././" etc.)
705  while (Path.size() > 2 && Path[0] == '.' && is_separator(Path[1], style)) {
706    Path = Path.substr(2);
707    while (Path.size() > 0 && is_separator(Path[0], style))
708      Path = Path.substr(1);
709  }
710  return Path;
711}
712
713// Remove path traversal components ("." and "..") when possible, and
714// canonicalize slashes.
715bool remove_dots(SmallVectorImpl<char> &the_path, bool remove_dot_dot,
716                 Style style) {
717  style = real_style(style);
718  StringRef remaining(the_path.data(), the_path.size());
719  bool needs_change = false;
720  SmallVector<StringRef, 16> components;
721
722  // Consume the root path, if present.
723  StringRef root = path::root_path(remaining, style);
724  bool absolute = !root.empty();
725  if (absolute)
726    remaining = remaining.drop_front(root.size());
727
728  // Loop over path components manually. This makes it easier to detect
729  // non-preferred slashes and double separators that must be canonicalized.
730  while (!remaining.empty()) {
731    size_t next_slash = remaining.find_first_of(separators(style));
732    if (next_slash == StringRef::npos)
733      next_slash = remaining.size();
734    StringRef component = remaining.take_front(next_slash);
735    remaining = remaining.drop_front(next_slash);
736
737    // Eat the slash, and check if it is the preferred separator.
738    if (!remaining.empty()) {
739      needs_change |= remaining.front() != preferred_separator(style);
740      remaining = remaining.drop_front();
741      // The path needs to be rewritten if it has a trailing slash.
742      // FIXME: This is emergent behavior that could be removed.
743      needs_change |= remaining.empty();
744    }
745
746    // Check for path traversal components or double separators.
747    if (component.empty() || component == ".") {
748      needs_change = true;
749    } else if (remove_dot_dot && component == "..") {
750      needs_change = true;
751      // Do not allow ".." to remove the root component. If this is the
752      // beginning of a relative path, keep the ".." component.
753      if (!components.empty() && components.back() != "..") {
754        components.pop_back();
755      } else if (!absolute) {
756        components.push_back(component);
757      }
758    } else {
759      components.push_back(component);
760    }
761  }
762
763  SmallString<256> buffer = root;
764  // "root" could be "/", which may need to be translated into "\".
765  make_preferred(buffer, style);
766  needs_change |= root != buffer;
767
768  // Avoid rewriting the path unless we have to.
769  if (!needs_change)
770    return false;
771
772  if (!components.empty()) {
773    buffer += components[0];
774    for (StringRef C : ArrayRef(components).drop_front()) {
775      buffer += preferred_separator(style);
776      buffer += C;
777    }
778  }
779  the_path.swap(buffer);
780  return true;
781}
782
783} // end namespace path
784
785namespace fs {
786
787std::error_code getUniqueID(const Twine Path, UniqueID &Result) {
788  file_status Status;
789  std::error_code EC = status(Path, Status);
790  if (EC)
791    return EC;
792  Result = Status.getUniqueID();
793  return std::error_code();
794}
795
796void createUniquePath(const Twine &Model, SmallVectorImpl<char> &ResultPath,
797                      bool MakeAbsolute) {
798  SmallString<128> ModelStorage;
799  Model.toVector(ModelStorage);
800
801  if (MakeAbsolute) {
802    // Make model absolute by prepending a temp directory if it's not already.
803    if (!sys::path::is_absolute(Twine(ModelStorage))) {
804      SmallString<128> TDir;
805      sys::path::system_temp_directory(true, TDir);
806      sys::path::append(TDir, Twine(ModelStorage));
807      ModelStorage.swap(TDir);
808    }
809  }
810
811  ResultPath = ModelStorage;
812  ResultPath.push_back(0);
813  ResultPath.pop_back();
814
815  // Replace '%' with random chars.
816  for (unsigned i = 0, e = ModelStorage.size(); i != e; ++i) {
817    if (ModelStorage[i] == '%')
818      ResultPath[i] = "0123456789abcdef"[sys::Process::GetRandomNumber() & 15];
819  }
820}
821
822std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
823                                 SmallVectorImpl<char> &ResultPath,
824                                 OpenFlags Flags, unsigned Mode) {
825  return createUniqueEntity(Model, ResultFd, ResultPath, false, FS_File, Flags,
826                            Mode);
827}
828
829std::error_code createUniqueFile(const Twine &Model,
830                                 SmallVectorImpl<char> &ResultPath,
831                                 unsigned Mode) {
832  int FD;
833  auto EC = createUniqueFile(Model, FD, ResultPath, OF_None, Mode);
834  if (EC)
835    return EC;
836  // FD is only needed to avoid race conditions. Close it right away.
837  close(FD);
838  return EC;
839}
840
841static std::error_code
842createTemporaryFile(const Twine &Model, int &ResultFD,
843                    llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type,
844                    sys::fs::OpenFlags Flags = sys::fs::OF_None) {
845  SmallString<128> Storage;
846  StringRef P = Model.toNullTerminatedStringRef(Storage);
847  assert(P.find_first_of(separators(Style::native)) == StringRef::npos &&
848         "Model must be a simple filename.");
849  // Use P.begin() so that createUniqueEntity doesn't need to recreate Storage.
850  return createUniqueEntity(P.begin(), ResultFD, ResultPath, true, Type, Flags,
851                            owner_read | owner_write);
852}
853
854static std::error_code
855createTemporaryFile(const Twine &Prefix, StringRef Suffix, int &ResultFD,
856                    llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type,
857                    sys::fs::OpenFlags Flags = sys::fs::OF_None) {
858  const char *Middle = Suffix.empty() ? "-%%%%%%" : "-%%%%%%.";
859  return createTemporaryFile(Prefix + Middle + Suffix, ResultFD, ResultPath,
860                             Type, Flags);
861}
862
863std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
864                                    int &ResultFD,
865                                    SmallVectorImpl<char> &ResultPath,
866                                    sys::fs::OpenFlags Flags) {
867  return createTemporaryFile(Prefix, Suffix, ResultFD, ResultPath, FS_File,
868                             Flags);
869}
870
871std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
872                                    SmallVectorImpl<char> &ResultPath,
873                                    sys::fs::OpenFlags Flags) {
874  int FD;
875  auto EC = createTemporaryFile(Prefix, Suffix, FD, ResultPath, Flags);
876  if (EC)
877    return EC;
878  // FD is only needed to avoid race conditions. Close it right away.
879  close(FD);
880  return EC;
881}
882
883// This is a mkdtemp with a different pattern. We use createUniqueEntity mostly
884// for consistency. We should try using mkdtemp.
885std::error_code createUniqueDirectory(const Twine &Prefix,
886                                      SmallVectorImpl<char> &ResultPath) {
887  int Dummy;
888  return createUniqueEntity(Prefix + "-%%%%%%", Dummy, ResultPath, true,
889                            FS_Dir);
890}
891
892std::error_code
893getPotentiallyUniqueFileName(const Twine &Model,
894                             SmallVectorImpl<char> &ResultPath) {
895  int Dummy;
896  return createUniqueEntity(Model, Dummy, ResultPath, false, FS_Name);
897}
898
899std::error_code
900getPotentiallyUniqueTempFileName(const Twine &Prefix, StringRef Suffix,
901                                 SmallVectorImpl<char> &ResultPath) {
902  int Dummy;
903  return createTemporaryFile(Prefix, Suffix, Dummy, ResultPath, FS_Name);
904}
905
906void make_absolute(const Twine &current_directory,
907                   SmallVectorImpl<char> &path) {
908  StringRef p(path.data(), path.size());
909
910  bool rootDirectory = path::has_root_directory(p);
911  bool rootName = path::has_root_name(p);
912
913  // Already absolute.
914  if ((rootName || is_style_posix(Style::native)) && rootDirectory)
915    return;
916
917  // All of the following conditions will need the current directory.
918  SmallString<128> current_dir;
919  current_directory.toVector(current_dir);
920
921  // Relative path. Prepend the current directory.
922  if (!rootName && !rootDirectory) {
923    // Append path to the current directory.
924    path::append(current_dir, p);
925    // Set path to the result.
926    path.swap(current_dir);
927    return;
928  }
929
930  if (!rootName && rootDirectory) {
931    StringRef cdrn = path::root_name(current_dir);
932    SmallString<128> curDirRootName(cdrn.begin(), cdrn.end());
933    path::append(curDirRootName, p);
934    // Set path to the result.
935    path.swap(curDirRootName);
936    return;
937  }
938
939  if (rootName && !rootDirectory) {
940    StringRef pRootName      = path::root_name(p);
941    StringRef bRootDirectory = path::root_directory(current_dir);
942    StringRef bRelativePath  = path::relative_path(current_dir);
943    StringRef pRelativePath  = path::relative_path(p);
944
945    SmallString<128> res;
946    path::append(res, pRootName, bRootDirectory, bRelativePath, pRelativePath);
947    path.swap(res);
948    return;
949  }
950
951  llvm_unreachable("All rootName and rootDirectory combinations should have "
952                   "occurred above!");
953}
954
955std::error_code make_absolute(SmallVectorImpl<char> &path) {
956  if (path::is_absolute(path))
957    return {};
958
959  SmallString<128> current_dir;
960  if (std::error_code ec = current_path(current_dir))
961    return ec;
962
963  make_absolute(current_dir, path);
964  return {};
965}
966
967std::error_code create_directories(const Twine &Path, bool IgnoreExisting,
968                                   perms Perms) {
969  SmallString<128> PathStorage;
970  StringRef P = Path.toStringRef(PathStorage);
971
972  // Be optimistic and try to create the directory
973  std::error_code EC = create_directory(P, IgnoreExisting, Perms);
974  // If we succeeded, or had any error other than the parent not existing, just
975  // return it.
976  if (EC != errc::no_such_file_or_directory)
977    return EC;
978
979  // We failed because of a no_such_file_or_directory, try to create the
980  // parent.
981  StringRef Parent = path::parent_path(P);
982  if (Parent.empty())
983    return EC;
984
985  if ((EC = create_directories(Parent, IgnoreExisting, Perms)))
986      return EC;
987
988  return create_directory(P, IgnoreExisting, Perms);
989}
990
991static std::error_code copy_file_internal(int ReadFD, int WriteFD) {
992  const size_t BufSize = 4096;
993  char *Buf = new char[BufSize];
994  int BytesRead = 0, BytesWritten = 0;
995  for (;;) {
996    BytesRead = read(ReadFD, Buf, BufSize);
997    if (BytesRead <= 0)
998      break;
999    while (BytesRead) {
1000      BytesWritten = write(WriteFD, Buf, BytesRead);
1001      if (BytesWritten < 0)
1002        break;
1003      BytesRead -= BytesWritten;
1004    }
1005    if (BytesWritten < 0)
1006      break;
1007  }
1008  delete[] Buf;
1009
1010  if (BytesRead < 0 || BytesWritten < 0)
1011    return std::error_code(errno, std::generic_category());
1012  return std::error_code();
1013}
1014
1015#ifndef __APPLE__
1016std::error_code copy_file(const Twine &From, const Twine &To) {
1017  int ReadFD, WriteFD;
1018  if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1019    return EC;
1020  if (std::error_code EC =
1021          openFileForWrite(To, WriteFD, CD_CreateAlways, OF_None)) {
1022    close(ReadFD);
1023    return EC;
1024  }
1025
1026  std::error_code EC = copy_file_internal(ReadFD, WriteFD);
1027
1028  close(ReadFD);
1029  close(WriteFD);
1030
1031  return EC;
1032}
1033#endif
1034
1035std::error_code copy_file(const Twine &From, int ToFD) {
1036  int ReadFD;
1037  if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1038    return EC;
1039
1040  std::error_code EC = copy_file_internal(ReadFD, ToFD);
1041
1042  close(ReadFD);
1043
1044  return EC;
1045}
1046
1047ErrorOr<MD5::MD5Result> md5_contents(int FD) {
1048  MD5 Hash;
1049
1050  constexpr size_t BufSize = 4096;
1051  std::vector<uint8_t> Buf(BufSize);
1052  int BytesRead = 0;
1053  for (;;) {
1054    BytesRead = read(FD, Buf.data(), BufSize);
1055    if (BytesRead <= 0)
1056      break;
1057    Hash.update(ArrayRef(Buf.data(), BytesRead));
1058  }
1059
1060  if (BytesRead < 0)
1061    return std::error_code(errno, std::generic_category());
1062  MD5::MD5Result Result;
1063  Hash.final(Result);
1064  return Result;
1065}
1066
1067ErrorOr<MD5::MD5Result> md5_contents(const Twine &Path) {
1068  int FD;
1069  if (auto EC = openFileForRead(Path, FD, OF_None))
1070    return EC;
1071
1072  auto Result = md5_contents(FD);
1073  close(FD);
1074  return Result;
1075}
1076
1077bool exists(const basic_file_status &status) {
1078  return status_known(status) && status.type() != file_type::file_not_found;
1079}
1080
1081bool status_known(const basic_file_status &s) {
1082  return s.type() != file_type::status_error;
1083}
1084
1085file_type get_file_type(const Twine &Path, bool Follow) {
1086  file_status st;
1087  if (status(Path, st, Follow))
1088    return file_type::status_error;
1089  return st.type();
1090}
1091
1092bool is_directory(const basic_file_status &status) {
1093  return status.type() == file_type::directory_file;
1094}
1095
1096std::error_code is_directory(const Twine &path, bool &result) {
1097  file_status st;
1098  if (std::error_code ec = status(path, st))
1099    return ec;
1100  result = is_directory(st);
1101  return std::error_code();
1102}
1103
1104bool is_regular_file(const basic_file_status &status) {
1105  return status.type() == file_type::regular_file;
1106}
1107
1108std::error_code is_regular_file(const Twine &path, bool &result) {
1109  file_status st;
1110  if (std::error_code ec = status(path, st))
1111    return ec;
1112  result = is_regular_file(st);
1113  return std::error_code();
1114}
1115
1116bool is_symlink_file(const basic_file_status &status) {
1117  return status.type() == file_type::symlink_file;
1118}
1119
1120std::error_code is_symlink_file(const Twine &path, bool &result) {
1121  file_status st;
1122  if (std::error_code ec = status(path, st, false))
1123    return ec;
1124  result = is_symlink_file(st);
1125  return std::error_code();
1126}
1127
1128bool is_other(const basic_file_status &status) {
1129  return exists(status) &&
1130         !is_regular_file(status) &&
1131         !is_directory(status);
1132}
1133
1134std::error_code is_other(const Twine &Path, bool &Result) {
1135  file_status FileStatus;
1136  if (std::error_code EC = status(Path, FileStatus))
1137    return EC;
1138  Result = is_other(FileStatus);
1139  return std::error_code();
1140}
1141
1142void directory_entry::replace_filename(const Twine &Filename, file_type Type,
1143                                       basic_file_status Status) {
1144  SmallString<128> PathStr = path::parent_path(Path);
1145  path::append(PathStr, Filename);
1146  this->Path = std::string(PathStr.str());
1147  this->Type = Type;
1148  this->Status = Status;
1149}
1150
1151ErrorOr<perms> getPermissions(const Twine &Path) {
1152  file_status Status;
1153  if (std::error_code EC = status(Path, Status))
1154    return EC;
1155
1156  return Status.permissions();
1157}
1158
1159size_t mapped_file_region::size() const {
1160  assert(Mapping && "Mapping failed but used anyway!");
1161  return Size;
1162}
1163
1164char *mapped_file_region::data() const {
1165  assert(Mapping && "Mapping failed but used anyway!");
1166  return reinterpret_cast<char *>(Mapping);
1167}
1168
1169const char *mapped_file_region::const_data() const {
1170  assert(Mapping && "Mapping failed but used anyway!");
1171  return reinterpret_cast<const char *>(Mapping);
1172}
1173
1174Error readNativeFileToEOF(file_t FileHandle, SmallVectorImpl<char> &Buffer,
1175                          ssize_t ChunkSize) {
1176  // Install a handler to truncate the buffer to the correct size on exit.
1177  size_t Size = Buffer.size();
1178  auto TruncateOnExit = make_scope_exit([&]() { Buffer.truncate(Size); });
1179
1180  // Read into Buffer until we hit EOF.
1181  for (;;) {
1182    Buffer.resize_for_overwrite(Size + ChunkSize);
1183    Expected<size_t> ReadBytes = readNativeFile(
1184        FileHandle, MutableArrayRef(Buffer.begin() + Size, ChunkSize));
1185    if (!ReadBytes)
1186      return ReadBytes.takeError();
1187    if (*ReadBytes == 0)
1188      return Error::success();
1189    Size += *ReadBytes;
1190  }
1191}
1192
1193} // end namespace fs
1194} // end namespace sys
1195} // end namespace llvm
1196
1197// Include the truly platform-specific parts.
1198#if defined(LLVM_ON_UNIX)
1199#include "Unix/Path.inc"
1200#endif
1201#if defined(_WIN32)
1202#include "Windows/Path.inc"
1203#endif
1204
1205bool IsLLVMDriver = false;
1206
1207namespace llvm {
1208namespace sys {
1209namespace fs {
1210
1211std::string getMainExecutable(const char *Argv0, void *MainAddr) {
1212  if (IsLLVMDriver)
1213    return sys::path::stem(Argv0).str();
1214  return getMainExecutableImpl(Argv0, MainAddr);
1215}
1216
1217TempFile::TempFile(StringRef Name, int FD)
1218    : TmpName(std::string(Name)), FD(FD) {}
1219TempFile::TempFile(TempFile &&Other) { *this = std::move(Other); }
1220TempFile &TempFile::operator=(TempFile &&Other) {
1221  TmpName = std::move(Other.TmpName);
1222  FD = Other.FD;
1223  Other.Done = true;
1224  Other.FD = -1;
1225#ifdef _WIN32
1226  RemoveOnClose = Other.RemoveOnClose;
1227  Other.RemoveOnClose = false;
1228#endif
1229  return *this;
1230}
1231
1232TempFile::~TempFile() { assert(Done); }
1233
1234Error TempFile::discard() {
1235  Done = true;
1236  if (FD != -1 && close(FD) == -1) {
1237    std::error_code EC = std::error_code(errno, std::generic_category());
1238    return errorCodeToError(EC);
1239  }
1240  FD = -1;
1241
1242#ifdef _WIN32
1243  // On Windows, closing will remove the file, if we set the delete
1244  // disposition. If not, remove it manually.
1245  bool Remove = RemoveOnClose;
1246#else
1247  // Always try to remove the file.
1248  bool Remove = true;
1249#endif
1250  std::error_code RemoveEC;
1251  if (Remove && !TmpName.empty()) {
1252    RemoveEC = fs::remove(TmpName);
1253    sys::DontRemoveFileOnSignal(TmpName);
1254    if (!RemoveEC)
1255      TmpName = "";
1256  } else {
1257    TmpName = "";
1258  }
1259  return errorCodeToError(RemoveEC);
1260}
1261
1262Error TempFile::keep(const Twine &Name) {
1263  assert(!Done);
1264  Done = true;
1265  // Always try to close and rename.
1266#ifdef _WIN32
1267  // If we can't cancel the delete don't rename.
1268  auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1269  std::error_code RenameEC =
1270      RemoveOnClose ? std::error_code() : setDeleteDisposition(H, false);
1271  bool ShouldDelete = false;
1272  if (!RenameEC) {
1273    RenameEC = rename_handle(H, Name);
1274    // If rename failed because it's cross-device, copy instead
1275    if (RenameEC ==
1276      std::error_code(ERROR_NOT_SAME_DEVICE, std::system_category())) {
1277      RenameEC = copy_file(TmpName, Name);
1278      ShouldDelete = true;
1279    }
1280  }
1281
1282  // If we can't rename or copy, discard the temporary file.
1283  if (RenameEC)
1284    ShouldDelete = true;
1285  if (ShouldDelete) {
1286    if (!RemoveOnClose)
1287      setDeleteDisposition(H, true);
1288    else
1289      remove(TmpName);
1290  }
1291#else
1292  std::error_code RenameEC = fs::rename(TmpName, Name);
1293  if (RenameEC) {
1294    // If we can't rename, try to copy to work around cross-device link issues.
1295    RenameEC = sys::fs::copy_file(TmpName, Name);
1296    // If we can't rename or copy, discard the temporary file.
1297    if (RenameEC)
1298      remove(TmpName);
1299  }
1300#endif
1301  sys::DontRemoveFileOnSignal(TmpName);
1302
1303  if (!RenameEC)
1304    TmpName = "";
1305
1306  if (close(FD) == -1) {
1307    std::error_code EC(errno, std::generic_category());
1308    return errorCodeToError(EC);
1309  }
1310  FD = -1;
1311
1312  return errorCodeToError(RenameEC);
1313}
1314
1315Error TempFile::keep() {
1316  assert(!Done);
1317  Done = true;
1318
1319#ifdef _WIN32
1320  auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1321  if (std::error_code EC = setDeleteDisposition(H, false))
1322    return errorCodeToError(EC);
1323#endif
1324  sys::DontRemoveFileOnSignal(TmpName);
1325
1326  TmpName = "";
1327
1328  if (close(FD) == -1) {
1329    std::error_code EC(errno, std::generic_category());
1330    return errorCodeToError(EC);
1331  }
1332  FD = -1;
1333
1334  return Error::success();
1335}
1336
1337Expected<TempFile> TempFile::create(const Twine &Model, unsigned Mode,
1338                                    OpenFlags ExtraFlags) {
1339  int FD;
1340  SmallString<128> ResultPath;
1341  if (std::error_code EC =
1342          createUniqueFile(Model, FD, ResultPath, OF_Delete | ExtraFlags, Mode))
1343    return errorCodeToError(EC);
1344
1345  TempFile Ret(ResultPath, FD);
1346#ifdef _WIN32
1347  auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1348  bool SetSignalHandler = false;
1349  if (std::error_code EC = setDeleteDisposition(H, true)) {
1350    Ret.RemoveOnClose = true;
1351    SetSignalHandler = true;
1352  }
1353#else
1354  bool SetSignalHandler = true;
1355#endif
1356  if (SetSignalHandler && sys::RemoveFileOnSignal(ResultPath)) {
1357    // Make sure we delete the file when RemoveFileOnSignal fails.
1358    consumeError(Ret.discard());
1359    std::error_code EC(errc::operation_not_permitted);
1360    return errorCodeToError(EC);
1361  }
1362  return std::move(Ret);
1363}
1364} // namespace fs
1365
1366} // namespace sys
1367} // namespace llvm
1368