lib/Support/Path.cpp

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