1//===-- Path.cpp - Implement OS Path Concept ------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file implements the operating system Path API.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Support/COFF.h"
15#include "llvm/Support/Endian.h"
16#include "llvm/Support/Errc.h"
17#include "llvm/Support/ErrorHandling.h"
18#include "llvm/Support/FileSystem.h"
19#include "llvm/Support/Path.h"
20#include "llvm/Support/Process.h"
21#include <cctype>
22#include <cstring>
23
24#if !defined(_MSC_VER) && !defined(__MINGW32__)
25#include <unistd.h>
26#else
27#include <io.h>
28#endif
29
30using namespace llvm;
31using namespace llvm::support::endian;
32
33namespace {
34  using llvm::StringRef;
35  using llvm::sys::path::is_separator;
36
37#ifdef LLVM_ON_WIN32
38  const char *separators = "\\/";
39  const char preferred_separator = '\\';
40#else
41  const char  separators = '/';
42  const char preferred_separator = '/';
43#endif
44
45  StringRef find_first_component(StringRef path) {
46    // Look for this first component in the following order.
47    // * empty (in this case we return an empty string)
48    // * either C: or {//,\\}net.
49    // * {/,\}
50    // * {file,directory}name
51
52    if (path.empty())
53      return path;
54
55#ifdef LLVM_ON_WIN32
56    // C:
57    if (path.size() >= 2 && std::isalpha(static_cast<unsigned char>(path[0])) &&
58        path[1] == ':')
59      return path.substr(0, 2);
60#endif
61
62    // //net
63    if ((path.size() > 2) &&
64        is_separator(path[0]) &&
65        path[0] == path[1] &&
66        !is_separator(path[2])) {
67      // Find the next directory separator.
68      size_t end = path.find_first_of(separators, 2);
69      return path.substr(0, end);
70    }
71
72    // {/,\}
73    if (is_separator(path[0]))
74      return path.substr(0, 1);
75
76    // * {file,directory}name
77    size_t end = path.find_first_of(separators);
78    return path.substr(0, end);
79  }
80
81  size_t filename_pos(StringRef str) {
82    if (str.size() == 2 &&
83        is_separator(str[0]) &&
84        str[0] == str[1])
85      return 0;
86
87    if (str.size() > 0 && is_separator(str[str.size() - 1]))
88      return str.size() - 1;
89
90    size_t pos = str.find_last_of(separators, str.size() - 1);
91
92#ifdef LLVM_ON_WIN32
93    if (pos == StringRef::npos)
94      pos = str.find_last_of(':', str.size() - 2);
95#endif
96
97    if (pos == StringRef::npos ||
98        (pos == 1 && is_separator(str[0])))
99      return 0;
100
101    return pos + 1;
102  }
103
104  size_t root_dir_start(StringRef str) {
105    // case "c:/"
106#ifdef LLVM_ON_WIN32
107    if (str.size() > 2 &&
108        str[1] == ':' &&
109        is_separator(str[2]))
110      return 2;
111#endif
112
113    // case "//"
114    if (str.size() == 2 &&
115        is_separator(str[0]) &&
116        str[0] == str[1])
117      return StringRef::npos;
118
119    // case "//net"
120    if (str.size() > 3 &&
121        is_separator(str[0]) &&
122        str[0] == str[1] &&
123        !is_separator(str[2])) {
124      return str.find_first_of(separators, 2);
125    }
126
127    // case "/"
128    if (str.size() > 0 && is_separator(str[0]))
129      return 0;
130
131    return StringRef::npos;
132  }
133
134  size_t parent_path_end(StringRef path) {
135    size_t end_pos = filename_pos(path);
136
137    bool filename_was_sep = path.size() > 0 && is_separator(path[end_pos]);
138
139    // Skip separators except for root dir.
140    size_t root_dir_pos = root_dir_start(path.substr(0, end_pos));
141
142    while(end_pos > 0 &&
143          (end_pos - 1) != root_dir_pos &&
144          is_separator(path[end_pos - 1]))
145      --end_pos;
146
147    if (end_pos == 1 && root_dir_pos == 0 && filename_was_sep)
148      return StringRef::npos;
149
150    return end_pos;
151  }
152} // end unnamed namespace
153
154enum FSEntity {
155  FS_Dir,
156  FS_File,
157  FS_Name
158};
159
160static std::error_code createUniqueEntity(const Twine &Model, int &ResultFD,
161                                          SmallVectorImpl<char> &ResultPath,
162                                          bool MakeAbsolute, unsigned Mode,
163                                          FSEntity Type) {
164  SmallString<128> ModelStorage;
165  Model.toVector(ModelStorage);
166
167  if (MakeAbsolute) {
168    // Make model absolute by prepending a temp directory if it's not already.
169    if (!sys::path::is_absolute(Twine(ModelStorage))) {
170      SmallString<128> TDir;
171      sys::path::system_temp_directory(true, TDir);
172      sys::path::append(TDir, Twine(ModelStorage));
173      ModelStorage.swap(TDir);
174    }
175  }
176
177  // From here on, DO NOT modify model. It may be needed if the randomly chosen
178  // path already exists.
179  ResultPath = ModelStorage;
180  // Null terminate.
181  ResultPath.push_back(0);
182  ResultPath.pop_back();
183
184retry_random_path:
185  // Replace '%' with random chars.
186  for (unsigned i = 0, e = ModelStorage.size(); i != e; ++i) {
187    if (ModelStorage[i] == '%')
188      ResultPath[i] = "0123456789abcdef"[sys::Process::GetRandomNumber() & 15];
189  }
190
191  // Try to open + create the file.
192  switch (Type) {
193  case FS_File: {
194    if (std::error_code EC =
195            sys::fs::openFileForWrite(Twine(ResultPath.begin()), ResultFD,
196                                      sys::fs::F_RW | sys::fs::F_Excl, Mode)) {
197      if (EC == errc::file_exists)
198        goto retry_random_path;
199      return EC;
200    }
201
202    return std::error_code();
203  }
204
205  case FS_Name: {
206    std::error_code EC =
207        sys::fs::access(ResultPath.begin(), sys::fs::AccessMode::Exist);
208    if (EC == errc::no_such_file_or_directory)
209      return std::error_code();
210    if (EC)
211      return EC;
212    goto retry_random_path;
213  }
214
215  case FS_Dir: {
216    if (std::error_code EC =
217            sys::fs::create_directory(ResultPath.begin(), false)) {
218      if (EC == errc::file_exists)
219        goto retry_random_path;
220      return EC;
221    }
222    return std::error_code();
223  }
224  }
225  llvm_unreachable("Invalid Type");
226}
227
228namespace llvm {
229namespace sys  {
230namespace path {
231
232const_iterator begin(StringRef path) {
233  const_iterator i;
234  i.Path      = path;
235  i.Component = find_first_component(path);
236  i.Position  = 0;
237  return i;
238}
239
240const_iterator end(StringRef path) {
241  const_iterator i;
242  i.Path      = path;
243  i.Position  = path.size();
244  return i;
245}
246
247const_iterator &const_iterator::operator++() {
248  assert(Position < Path.size() && "Tried to increment past end!");
249
250  // Increment Position to past the current component
251  Position += Component.size();
252
253  // Check for end.
254  if (Position == Path.size()) {
255    Component = StringRef();
256    return *this;
257  }
258
259  // Both POSIX and Windows treat paths that begin with exactly two separators
260  // specially.
261  bool was_net = Component.size() > 2 &&
262    is_separator(Component[0]) &&
263    Component[1] == Component[0] &&
264    !is_separator(Component[2]);
265
266  // Handle separators.
267  if (is_separator(Path[Position])) {
268    // Root dir.
269    if (was_net
270#ifdef LLVM_ON_WIN32
271        // c:/
272        || Component.endswith(":")
273#endif
274        ) {
275      Component = Path.substr(Position, 1);
276      return *this;
277    }
278
279    // Skip extra separators.
280    while (Position != Path.size() &&
281           is_separator(Path[Position])) {
282      ++Position;
283    }
284
285    // Treat trailing '/' as a '.'.
286    if (Position == Path.size()) {
287      --Position;
288      Component = ".";
289      return *this;
290    }
291  }
292
293  // Find next component.
294  size_t end_pos = Path.find_first_of(separators, Position);
295  Component = Path.slice(Position, end_pos);
296
297  return *this;
298}
299
300bool const_iterator::operator==(const const_iterator &RHS) const {
301  return Path.begin() == RHS.Path.begin() && Position == RHS.Position;
302}
303
304ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
305  return Position - RHS.Position;
306}
307
308reverse_iterator rbegin(StringRef Path) {
309  reverse_iterator I;
310  I.Path = Path;
311  I.Position = Path.size();
312  return ++I;
313}
314
315reverse_iterator rend(StringRef Path) {
316  reverse_iterator I;
317  I.Path = Path;
318  I.Component = Path.substr(0, 0);
319  I.Position = 0;
320  return I;
321}
322
323reverse_iterator &reverse_iterator::operator++() {
324  // If we're at the end and the previous char was a '/', return '.' unless
325  // we are the root path.
326  size_t root_dir_pos = root_dir_start(Path);
327  if (Position == Path.size() &&
328      Path.size() > root_dir_pos + 1 &&
329      is_separator(Path[Position - 1])) {
330    --Position;
331    Component = ".";
332    return *this;
333  }
334
335  // Skip separators unless it's the root directory.
336  size_t end_pos = Position;
337
338  while(end_pos > 0 &&
339        (end_pos - 1) != root_dir_pos &&
340        is_separator(Path[end_pos - 1]))
341    --end_pos;
342
343  // Find next separator.
344  size_t start_pos = filename_pos(Path.substr(0, end_pos));
345  Component = Path.slice(start_pos, end_pos);
346  Position = start_pos;
347  return *this;
348}
349
350bool reverse_iterator::operator==(const reverse_iterator &RHS) const {
351  return Path.begin() == RHS.Path.begin() && Component == RHS.Component &&
352         Position == RHS.Position;
353}
354
355StringRef root_path(StringRef path) {
356  const_iterator b = begin(path),
357                 pos = b,
358                 e = end(path);
359  if (b != e) {
360    bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
361    bool has_drive =
362#ifdef LLVM_ON_WIN32
363      b->endswith(":");
364#else
365      false;
366#endif
367
368    if (has_net || has_drive) {
369      if ((++pos != e) && is_separator((*pos)[0])) {
370        // {C:/,//net/}, so get the first two components.
371        return path.substr(0, b->size() + pos->size());
372      } else {
373        // just {C:,//net}, return the first component.
374        return *b;
375      }
376    }
377
378    // POSIX style root directory.
379    if (is_separator((*b)[0])) {
380      return *b;
381    }
382  }
383
384  return StringRef();
385}
386
387StringRef root_name(StringRef path) {
388  const_iterator b = begin(path),
389                 e = end(path);
390  if (b != e) {
391    bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
392    bool has_drive =
393#ifdef LLVM_ON_WIN32
394      b->endswith(":");
395#else
396      false;
397#endif
398
399    if (has_net || has_drive) {
400      // just {C:,//net}, return the first component.
401      return *b;
402    }
403  }
404
405  // No path or no name.
406  return StringRef();
407}
408
409StringRef root_directory(StringRef path) {
410  const_iterator b = begin(path),
411                 pos = b,
412                 e = end(path);
413  if (b != e) {
414    bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
415    bool has_drive =
416#ifdef LLVM_ON_WIN32
417      b->endswith(":");
418#else
419      false;
420#endif
421
422    if ((has_net || has_drive) &&
423        // {C:,//net}, skip to the next component.
424        (++pos != e) && is_separator((*pos)[0])) {
425      return *pos;
426    }
427
428    // POSIX style root directory.
429    if (!has_net && is_separator((*b)[0])) {
430      return *b;
431    }
432  }
433
434  // No path or no root.
435  return StringRef();
436}
437
438StringRef relative_path(StringRef path) {
439  StringRef root = root_path(path);
440  return path.substr(root.size());
441}
442
443void append(SmallVectorImpl<char> &path, const Twine &a,
444                                         const Twine &b,
445                                         const Twine &c,
446                                         const Twine &d) {
447  SmallString<32> a_storage;
448  SmallString<32> b_storage;
449  SmallString<32> c_storage;
450  SmallString<32> d_storage;
451
452  SmallVector<StringRef, 4> components;
453  if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
454  if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
455  if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
456  if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
457
458  for (auto &component : components) {
459    bool path_has_sep = !path.empty() && is_separator(path[path.size() - 1]);
460    bool component_has_sep = !component.empty() && is_separator(component[0]);
461    bool is_root_name = has_root_name(component);
462
463    if (path_has_sep) {
464      // Strip separators from beginning of component.
465      size_t loc = component.find_first_not_of(separators);
466      StringRef c = component.substr(loc);
467
468      // Append it.
469      path.append(c.begin(), c.end());
470      continue;
471    }
472
473    if (!component_has_sep && !(path.empty() || is_root_name)) {
474      // Add a separator.
475      path.push_back(preferred_separator);
476    }
477
478    path.append(component.begin(), component.end());
479  }
480}
481
482void append(SmallVectorImpl<char> &path,
483            const_iterator begin, const_iterator end) {
484  for (; begin != end; ++begin)
485    path::append(path, *begin);
486}
487
488StringRef parent_path(StringRef path) {
489  size_t end_pos = parent_path_end(path);
490  if (end_pos == StringRef::npos)
491    return StringRef();
492  else
493    return path.substr(0, end_pos);
494}
495
496void remove_filename(SmallVectorImpl<char> &path) {
497  size_t end_pos = parent_path_end(StringRef(path.begin(), path.size()));
498  if (end_pos != StringRef::npos)
499    path.set_size(end_pos);
500}
501
502void replace_extension(SmallVectorImpl<char> &path, const Twine &extension) {
503  StringRef p(path.begin(), path.size());
504  SmallString<32> ext_storage;
505  StringRef ext = extension.toStringRef(ext_storage);
506
507  // Erase existing extension.
508  size_t pos = p.find_last_of('.');
509  if (pos != StringRef::npos && pos >= filename_pos(p))
510    path.set_size(pos);
511
512  // Append '.' if needed.
513  if (ext.size() > 0 && ext[0] != '.')
514    path.push_back('.');
515
516  // Append extension.
517  path.append(ext.begin(), ext.end());
518}
519
520void native(const Twine &path, SmallVectorImpl<char> &result) {
521  assert((!path.isSingleStringRef() ||
522          path.getSingleStringRef().data() != result.data()) &&
523         "path and result are not allowed to overlap!");
524  // Clear result.
525  result.clear();
526  path.toVector(result);
527  native(result);
528}
529
530void native(SmallVectorImpl<char> &Path) {
531#ifdef LLVM_ON_WIN32
532  std::replace(Path.begin(), Path.end(), '/', '\\');
533#else
534  for (auto PI = Path.begin(), PE = Path.end(); PI < PE; ++PI) {
535    if (*PI == '\\') {
536      auto PN = PI + 1;
537      if (PN < PE && *PN == '\\')
538        ++PI; // increment once, the for loop will move over the escaped slash
539      else
540        *PI = '/';
541    }
542  }
543#endif
544}
545
546StringRef filename(StringRef path) {
547  return *rbegin(path);
548}
549
550StringRef stem(StringRef path) {
551  StringRef fname = filename(path);
552  size_t pos = fname.find_last_of('.');
553  if (pos == StringRef::npos)
554    return fname;
555  else
556    if ((fname.size() == 1 && fname == ".") ||
557        (fname.size() == 2 && fname == ".."))
558      return fname;
559    else
560      return fname.substr(0, pos);
561}
562
563StringRef extension(StringRef path) {
564  StringRef fname = filename(path);
565  size_t pos = fname.find_last_of('.');
566  if (pos == StringRef::npos)
567    return StringRef();
568  else
569    if ((fname.size() == 1 && fname == ".") ||
570        (fname.size() == 2 && fname == ".."))
571      return StringRef();
572    else
573      return fname.substr(pos);
574}
575
576bool is_separator(char value) {
577  switch(value) {
578#ifdef LLVM_ON_WIN32
579    case '\\': // fall through
580#endif
581    case '/': return true;
582    default: return false;
583  }
584}
585
586static const char preferred_separator_string[] = { preferred_separator, '\0' };
587
588StringRef get_separator() {
589  return preferred_separator_string;
590}
591
592bool has_root_name(const Twine &path) {
593  SmallString<128> path_storage;
594  StringRef p = path.toStringRef(path_storage);
595
596  return !root_name(p).empty();
597}
598
599bool has_root_directory(const Twine &path) {
600  SmallString<128> path_storage;
601  StringRef p = path.toStringRef(path_storage);
602
603  return !root_directory(p).empty();
604}
605
606bool has_root_path(const Twine &path) {
607  SmallString<128> path_storage;
608  StringRef p = path.toStringRef(path_storage);
609
610  return !root_path(p).empty();
611}
612
613bool has_relative_path(const Twine &path) {
614  SmallString<128> path_storage;
615  StringRef p = path.toStringRef(path_storage);
616
617  return !relative_path(p).empty();
618}
619
620bool has_filename(const Twine &path) {
621  SmallString<128> path_storage;
622  StringRef p = path.toStringRef(path_storage);
623
624  return !filename(p).empty();
625}
626
627bool has_parent_path(const Twine &path) {
628  SmallString<128> path_storage;
629  StringRef p = path.toStringRef(path_storage);
630
631  return !parent_path(p).empty();
632}
633
634bool has_stem(const Twine &path) {
635  SmallString<128> path_storage;
636  StringRef p = path.toStringRef(path_storage);
637
638  return !stem(p).empty();
639}
640
641bool has_extension(const Twine &path) {
642  SmallString<128> path_storage;
643  StringRef p = path.toStringRef(path_storage);
644
645  return !extension(p).empty();
646}
647
648bool is_absolute(const Twine &path) {
649  SmallString<128> path_storage;
650  StringRef p = path.toStringRef(path_storage);
651
652  bool rootDir = has_root_directory(p),
653#ifdef LLVM_ON_WIN32
654       rootName = has_root_name(p);
655#else
656       rootName = true;
657#endif
658
659  return rootDir && rootName;
660}
661
662bool is_relative(const Twine &path) { return !is_absolute(path); }
663
664StringRef remove_leading_dotslash(StringRef Path) {
665  // Remove leading "./" (or ".//" or "././" etc.)
666  while (Path.size() > 2 && Path[0] == '.' && is_separator(Path[1])) {
667    Path = Path.substr(2);
668    while (Path.size() > 0 && is_separator(Path[0]))
669      Path = Path.substr(1);
670  }
671  return Path;
672}
673
674static SmallString<256> remove_dots(StringRef path, bool remove_dot_dot) {
675  SmallVector<StringRef, 16> components;
676
677  // Skip the root path, then look for traversal in the components.
678  StringRef rel = path::relative_path(path);
679  for (StringRef C : llvm::make_range(path::begin(rel), path::end(rel))) {
680    if (C == ".")
681      continue;
682    if (remove_dot_dot) {
683      if (C == "..") {
684        if (!components.empty())
685          components.pop_back();
686        continue;
687      }
688    }
689    components.push_back(C);
690  }
691
692  SmallString<256> buffer = path::root_path(path);
693  for (StringRef C : components)
694    path::append(buffer, C);
695  return buffer;
696}
697
698bool remove_dots(SmallVectorImpl<char> &path, bool remove_dot_dot) {
699  StringRef p(path.data(), path.size());
700
701  SmallString<256> result = remove_dots(p, remove_dot_dot);
702  if (result == path)
703    return false;
704
705  path.swap(result);
706  return true;
707}
708
709} // end namespace path
710
711namespace fs {
712
713std::error_code getUniqueID(const Twine Path, UniqueID &Result) {
714  file_status Status;
715  std::error_code EC = status(Path, Status);
716  if (EC)
717    return EC;
718  Result = Status.getUniqueID();
719  return std::error_code();
720}
721
722std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
723                                 SmallVectorImpl<char> &ResultPath,
724                                 unsigned Mode) {
725  return createUniqueEntity(Model, ResultFd, ResultPath, false, Mode, FS_File);
726}
727
728std::error_code createUniqueFile(const Twine &Model,
729                                 SmallVectorImpl<char> &ResultPath) {
730  int Dummy;
731  return createUniqueEntity(Model, Dummy, ResultPath, false, 0, FS_Name);
732}
733
734static std::error_code
735createTemporaryFile(const Twine &Model, int &ResultFD,
736                    llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type) {
737  SmallString<128> Storage;
738  StringRef P = Model.toNullTerminatedStringRef(Storage);
739  assert(P.find_first_of(separators) == StringRef::npos &&
740         "Model must be a simple filename.");
741  // Use P.begin() so that createUniqueEntity doesn't need to recreate Storage.
742  return createUniqueEntity(P.begin(), ResultFD, ResultPath,
743                            true, owner_read | owner_write, Type);
744}
745
746static std::error_code
747createTemporaryFile(const Twine &Prefix, StringRef Suffix, int &ResultFD,
748                    llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type) {
749  const char *Middle = Suffix.empty() ? "-%%%%%%" : "-%%%%%%.";
750  return createTemporaryFile(Prefix + Middle + Suffix, ResultFD, ResultPath,
751                             Type);
752}
753
754std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
755                                    int &ResultFD,
756                                    SmallVectorImpl<char> &ResultPath) {
757  return createTemporaryFile(Prefix, Suffix, ResultFD, ResultPath, FS_File);
758}
759
760std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
761                                    SmallVectorImpl<char> &ResultPath) {
762  int Dummy;
763  return createTemporaryFile(Prefix, Suffix, Dummy, ResultPath, FS_Name);
764}
765
766
767// This is a mkdtemp with a different pattern. We use createUniqueEntity mostly
768// for consistency. We should try using mkdtemp.
769std::error_code createUniqueDirectory(const Twine &Prefix,
770                                      SmallVectorImpl<char> &ResultPath) {
771  int Dummy;
772  return createUniqueEntity(Prefix + "-%%%%%%", Dummy, ResultPath,
773                            true, 0, FS_Dir);
774}
775
776static std::error_code make_absolute(const Twine &current_directory,
777                                     SmallVectorImpl<char> &path,
778                                     bool use_current_directory) {
779  StringRef p(path.data(), path.size());
780
781  bool rootDirectory = path::has_root_directory(p),
782#ifdef LLVM_ON_WIN32
783       rootName = path::has_root_name(p);
784#else
785       rootName = true;
786#endif
787
788  // Already absolute.
789  if (rootName && rootDirectory)
790    return std::error_code();
791
792  // All of the following conditions will need the current directory.
793  SmallString<128> current_dir;
794  if (use_current_directory)
795    current_directory.toVector(current_dir);
796  else if (std::error_code ec = current_path(current_dir))
797    return ec;
798
799  // Relative path. Prepend the current directory.
800  if (!rootName && !rootDirectory) {
801    // Append path to the current directory.
802    path::append(current_dir, p);
803    // Set path to the result.
804    path.swap(current_dir);
805    return std::error_code();
806  }
807
808  if (!rootName && rootDirectory) {
809    StringRef cdrn = path::root_name(current_dir);
810    SmallString<128> curDirRootName(cdrn.begin(), cdrn.end());
811    path::append(curDirRootName, p);
812    // Set path to the result.
813    path.swap(curDirRootName);
814    return std::error_code();
815  }
816
817  if (rootName && !rootDirectory) {
818    StringRef pRootName      = path::root_name(p);
819    StringRef bRootDirectory = path::root_directory(current_dir);
820    StringRef bRelativePath  = path::relative_path(current_dir);
821    StringRef pRelativePath  = path::relative_path(p);
822
823    SmallString<128> res;
824    path::append(res, pRootName, bRootDirectory, bRelativePath, pRelativePath);
825    path.swap(res);
826    return std::error_code();
827  }
828
829  llvm_unreachable("All rootName and rootDirectory combinations should have "
830                   "occurred above!");
831}
832
833std::error_code make_absolute(const Twine &current_directory,
834                              SmallVectorImpl<char> &path) {
835  return make_absolute(current_directory, path, true);
836}
837
838std::error_code make_absolute(SmallVectorImpl<char> &path) {
839  return make_absolute(Twine(), path, false);
840}
841
842std::error_code create_directories(const Twine &Path, bool IgnoreExisting,
843                                   perms Perms) {
844  SmallString<128> PathStorage;
845  StringRef P = Path.toStringRef(PathStorage);
846
847  // Be optimistic and try to create the directory
848  std::error_code EC = create_directory(P, IgnoreExisting, Perms);
849  // If we succeeded, or had any error other than the parent not existing, just
850  // return it.
851  if (EC != errc::no_such_file_or_directory)
852    return EC;
853
854  // We failed because of a no_such_file_or_directory, try to create the
855  // parent.
856  StringRef Parent = path::parent_path(P);
857  if (Parent.empty())
858    return EC;
859
860  if ((EC = create_directories(Parent, IgnoreExisting, Perms)))
861      return EC;
862
863  return create_directory(P, IgnoreExisting, Perms);
864}
865
866std::error_code copy_file(const Twine &From, const Twine &To) {
867  int ReadFD, WriteFD;
868  if (std::error_code EC = openFileForRead(From, ReadFD))
869    return EC;
870  if (std::error_code EC = openFileForWrite(To, WriteFD, F_None)) {
871    close(ReadFD);
872    return EC;
873  }
874
875  const size_t BufSize = 4096;
876  char *Buf = new char[BufSize];
877  int BytesRead = 0, BytesWritten = 0;
878  for (;;) {
879    BytesRead = read(ReadFD, Buf, BufSize);
880    if (BytesRead <= 0)
881      break;
882    while (BytesRead) {
883      BytesWritten = write(WriteFD, Buf, BytesRead);
884      if (BytesWritten < 0)
885        break;
886      BytesRead -= BytesWritten;
887    }
888    if (BytesWritten < 0)
889      break;
890  }
891  close(ReadFD);
892  close(WriteFD);
893  delete[] Buf;
894
895  if (BytesRead < 0 || BytesWritten < 0)
896    return std::error_code(errno, std::generic_category());
897  return std::error_code();
898}
899
900bool exists(file_status status) {
901  return status_known(status) && status.type() != file_type::file_not_found;
902}
903
904bool status_known(file_status s) {
905  return s.type() != file_type::status_error;
906}
907
908bool is_directory(file_status status) {
909  return status.type() == file_type::directory_file;
910}
911
912std::error_code is_directory(const Twine &path, bool &result) {
913  file_status st;
914  if (std::error_code ec = status(path, st))
915    return ec;
916  result = is_directory(st);
917  return std::error_code();
918}
919
920bool is_regular_file(file_status status) {
921  return status.type() == file_type::regular_file;
922}
923
924std::error_code is_regular_file(const Twine &path, bool &result) {
925  file_status st;
926  if (std::error_code ec = status(path, st))
927    return ec;
928  result = is_regular_file(st);
929  return std::error_code();
930}
931
932bool is_other(file_status status) {
933  return exists(status) &&
934         !is_regular_file(status) &&
935         !is_directory(status);
936}
937
938std::error_code is_other(const Twine &Path, bool &Result) {
939  file_status FileStatus;
940  if (std::error_code EC = status(Path, FileStatus))
941    return EC;
942  Result = is_other(FileStatus);
943  return std::error_code();
944}
945
946void directory_entry::replace_filename(const Twine &filename, file_status st) {
947  SmallString<128> path = path::parent_path(Path);
948  path::append(path, filename);
949  Path = path.str();
950  Status = st;
951}
952
953/// @brief Identify the magic in magic.
954file_magic identify_magic(StringRef Magic) {
955  if (Magic.size() < 4)
956    return file_magic::unknown;
957  switch ((unsigned char)Magic[0]) {
958    case 0x00: {
959      // COFF bigobj or short import library file
960      if (Magic[1] == (char)0x00 && Magic[2] == (char)0xff &&
961          Magic[3] == (char)0xff) {
962        size_t MinSize = offsetof(COFF::BigObjHeader, UUID) + sizeof(COFF::BigObjMagic);
963        if (Magic.size() < MinSize)
964          return file_magic::coff_import_library;
965
966        int BigObjVersion = read16le(
967            Magic.data() + offsetof(COFF::BigObjHeader, Version));
968        if (BigObjVersion < COFF::BigObjHeader::MinBigObjectVersion)
969          return file_magic::coff_import_library;
970
971        const char *Start = Magic.data() + offsetof(COFF::BigObjHeader, UUID);
972        if (memcmp(Start, COFF::BigObjMagic, sizeof(COFF::BigObjMagic)) != 0)
973          return file_magic::coff_import_library;
974        return file_magic::coff_object;
975      }
976      // Windows resource file
977      const char Expected[] = { 0, 0, 0, 0, '\x20', 0, 0, 0, '\xff' };
978      if (Magic.size() >= sizeof(Expected) &&
979          memcmp(Magic.data(), Expected, sizeof(Expected)) == 0)
980        return file_magic::windows_resource;
981      // 0x0000 = COFF unknown machine type
982      if (Magic[1] == 0)
983        return file_magic::coff_object;
984      break;
985    }
986    case 0xDE:  // 0x0B17C0DE = BC wraper
987      if (Magic[1] == (char)0xC0 && Magic[2] == (char)0x17 &&
988          Magic[3] == (char)0x0B)
989        return file_magic::bitcode;
990      break;
991    case 'B':
992      if (Magic[1] == 'C' && Magic[2] == (char)0xC0 && Magic[3] == (char)0xDE)
993        return file_magic::bitcode;
994      break;
995    case '!':
996      if (Magic.size() >= 8)
997        if (memcmp(Magic.data(), "!<arch>\n", 8) == 0 ||
998            memcmp(Magic.data(), "!<thin>\n", 8) == 0)
999          return file_magic::archive;
1000      break;
1001
1002    case '\177':
1003      if (Magic.size() >= 18 && Magic[1] == 'E' && Magic[2] == 'L' &&
1004          Magic[3] == 'F') {
1005        bool Data2MSB = Magic[5] == 2;
1006        unsigned high = Data2MSB ? 16 : 17;
1007        unsigned low  = Data2MSB ? 17 : 16;
1008        if (Magic[high] == 0)
1009          switch (Magic[low]) {
1010            default: return file_magic::elf;
1011            case 1: return file_magic::elf_relocatable;
1012            case 2: return file_magic::elf_executable;
1013            case 3: return file_magic::elf_shared_object;
1014            case 4: return file_magic::elf_core;
1015          }
1016        else
1017          // It's still some type of ELF file.
1018          return file_magic::elf;
1019      }
1020      break;
1021
1022    case 0xCA:
1023      if (Magic[1] == char(0xFE) && Magic[2] == char(0xBA) &&
1024          Magic[3] == char(0xBE)) {
1025        // This is complicated by an overlap with Java class files.
1026        // See the Mach-O section in /usr/share/file/magic for details.
1027        if (Magic.size() >= 8 && Magic[7] < 43)
1028          return file_magic::macho_universal_binary;
1029      }
1030      break;
1031
1032      // The two magic numbers for mach-o are:
1033      // 0xfeedface - 32-bit mach-o
1034      // 0xfeedfacf - 64-bit mach-o
1035    case 0xFE:
1036    case 0xCE:
1037    case 0xCF: {
1038      uint16_t type = 0;
1039      if (Magic[0] == char(0xFE) && Magic[1] == char(0xED) &&
1040          Magic[2] == char(0xFA) &&
1041          (Magic[3] == char(0xCE) || Magic[3] == char(0xCF))) {
1042        /* Native endian */
1043        if (Magic.size() >= 16) type = Magic[14] << 8 | Magic[15];
1044      } else if ((Magic[0] == char(0xCE) || Magic[0] == char(0xCF)) &&
1045                 Magic[1] == char(0xFA) && Magic[2] == char(0xED) &&
1046                 Magic[3] == char(0xFE)) {
1047        /* Reverse endian */
1048        if (Magic.size() >= 14) type = Magic[13] << 8 | Magic[12];
1049      }
1050      switch (type) {
1051        default: break;
1052        case 1: return file_magic::macho_object;
1053        case 2: return file_magic::macho_executable;
1054        case 3: return file_magic::macho_fixed_virtual_memory_shared_lib;
1055        case 4: return file_magic::macho_core;
1056        case 5: return file_magic::macho_preload_executable;
1057        case 6: return file_magic::macho_dynamically_linked_shared_lib;
1058        case 7: return file_magic::macho_dynamic_linker;
1059        case 8: return file_magic::macho_bundle;
1060        case 9: return file_magic::macho_dynamically_linked_shared_lib_stub;
1061        case 10: return file_magic::macho_dsym_companion;
1062        case 11: return file_magic::macho_kext_bundle;
1063      }
1064      break;
1065    }
1066    case 0xF0: // PowerPC Windows
1067    case 0x83: // Alpha 32-bit
1068    case 0x84: // Alpha 64-bit
1069    case 0x66: // MPS R4000 Windows
1070    case 0x50: // mc68K
1071    case 0x4c: // 80386 Windows
1072    case 0xc4: // ARMNT Windows
1073      if (Magic[1] == 0x01)
1074        return file_magic::coff_object;
1075
1076    case 0x90: // PA-RISC Windows
1077    case 0x68: // mc68K Windows
1078      if (Magic[1] == 0x02)
1079        return file_magic::coff_object;
1080      break;
1081
1082    case 'M': // Possible MS-DOS stub on Windows PE file
1083      if (Magic[1] == 'Z') {
1084        uint32_t off = read32le(Magic.data() + 0x3c);
1085        // PE/COFF file, either EXE or DLL.
1086        if (off < Magic.size() &&
1087            memcmp(Magic.data()+off, COFF::PEMagic, sizeof(COFF::PEMagic)) == 0)
1088          return file_magic::pecoff_executable;
1089      }
1090      break;
1091
1092    case 0x64: // x86-64 Windows.
1093      if (Magic[1] == char(0x86))
1094        return file_magic::coff_object;
1095      break;
1096
1097    default:
1098      break;
1099  }
1100  return file_magic::unknown;
1101}
1102
1103std::error_code identify_magic(const Twine &Path, file_magic &Result) {
1104  int FD;
1105  if (std::error_code EC = openFileForRead(Path, FD))
1106    return EC;
1107
1108  char Buffer[32];
1109  int Length = read(FD, Buffer, sizeof(Buffer));
1110  if (close(FD) != 0 || Length < 0)
1111    return std::error_code(errno, std::generic_category());
1112
1113  Result = identify_magic(StringRef(Buffer, Length));
1114  return std::error_code();
1115}
1116
1117std::error_code directory_entry::status(file_status &result) const {
1118  return fs::status(Path, result);
1119}
1120
1121} // end namespace fs
1122} // end namespace sys
1123} // end namespace llvm
1124
1125// Include the truly platform-specific parts.
1126#if defined(LLVM_ON_UNIX)
1127#include "Unix/Path.inc"
1128#endif
1129#if defined(LLVM_ON_WIN32)
1130#include "Windows/Path.inc"
1131#endif
1132
1133namespace llvm {
1134namespace sys {
1135namespace path {
1136
1137bool user_cache_directory(SmallVectorImpl<char> &Result, const Twine &Path1,
1138                          const Twine &Path2, const Twine &Path3) {
1139  if (getUserCacheDir(Result)) {
1140    append(Result, Path1, Path2, Path3);
1141    return true;
1142  }
1143  return false;
1144}
1145
1146} // end namespace path
1147} // end namsspace sys
1148} // end namespace llvm
1149