lib/Support/Path.cpp

   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/Path.h"
  15 #include "llvm/ADT/ArrayRef.h"
  16 #include "llvm/Config/llvm-config.h"
  17 #include "llvm/Support/Endian.h"
  18 #include "llvm/Support/Errc.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20 #include "llvm/Support/FileSystem.h"
  21 #include "llvm/Support/Process.h"
  22 #include "llvm/Support/Signals.h"
  23 #include <cctype>
  24 #include <cstring>
  25
  26 #if !defined(_MSC_VER) && !defined(__MINGW32__)
  27 #include <unistd.h>
  28 #else
  29 #include <io.h>
  30 #endif
  31
  32 using namespace llvm;
  33 using namespace llvm::support::endian;
  34
  35 namespace {
  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 #ifdef _WIN32
  42     return (style == Style::posix) ? Style::posix : Style::windows;
  43 #else
  44     return (style == Style::windows) ? Style::windows : Style::posix;
  45 #endif
  46   }
  47
  48   inline const char *separators(Style style) {
  49     if (real_style(style) == Style::windows)
  50       return "\\/";
  51     return "/";
  52   }
  53
  54   inline char preferred_separator(Style style) {
  55     if (real_style(style) == Style::windows)
  56       return '\\';
  57     return '/';
  58   }
  59
  60   StringRef find_first_component(StringRef path, Style style) {
  61     // Look for this first component in the following order.
  62     // * empty (in this case we return an empty string)
  63     // * either C: or {//,\\}net.
  64     // * {/,\}
  65     // * {file,directory}name
  66
  67     if (path.empty())
  68       return path;
  69
  70     if (real_style(style) == Style::windows) {
  71       // C:
  72       if (path.size() >= 2 &&
  73           std::isalpha(static_cast<unsigned char>(path[0])) && path[1] == ':')
  74         return path.substr(0, 2);
  75     }
  76
  77     // //net
  78     if ((path.size() > 2) && is_separator(path[0], style) &&
  79         path[0] == path[1] && !is_separator(path[2], style)) {
  80       // Find the next directory separator.
  81       size_t end = path.find_first_of(separators(style), 2);
  82       return path.substr(0, end);
  83     }
  84
  85     // {/,\}
  86     if (is_separator(path[0], style))
  87       return path.substr(0, 1);
  88
  89     // * {file,directory}name
  90     size_t end = path.find_first_of(separators(style));
  91     return path.substr(0, end);
  92   }
  93
  94   // Returns the first character of the filename in str. For paths ending in
  95   // '/', it returns the position of the '/'.
  96   size_t filename_pos(StringRef str, Style style) {
  97     if (str.size() > 0 && is_separator(str[str.size() - 1], style))
  98       return str.size() - 1;
  99
 100     size_t pos = str.find_last_of(separators(style), str.size() - 1);
 101
 102     if (real_style(style) == Style::windows) {
 103       if (pos == StringRef::npos)
 104         pos = str.find_last_of(':', str.size() - 2);
 105     }
 106
 107     if (pos == StringRef::npos || (pos == 1 && is_separator(str[0], style)))
 108       return 0;
 109
 110     return pos + 1;
 111   }
 112
 113   // Returns the position of the root directory in str. If there is no root
 114   // directory in str, it returns StringRef::npos.
 115   size_t root_dir_start(StringRef str, Style style) {
 116     // case "c:/"
 117     if (real_style(style) == Style::windows) {
 118       if (str.size() > 2 && str[1] == ':' && is_separator(str[2], style))
 119         return 2;
 120     }
 121
 122     // case "//net"
 123     if (str.size() > 3 && is_separator(str[0], style) && str[0] == str[1] &&
 124         !is_separator(str[2], style)) {
 125       return str.find_first_of(separators(style), 2);
 126     }
 127
 128     // case "/"
 129     if (str.size() > 0 && is_separator(str[0], style))
 130       return 0;
 131
 132     return StringRef::npos;
 133   }
 134
 135   // Returns the position past the end of the "parent path" of path. The parent
 136   // path will not end in '/', unless the parent is the root directory. If the
 137   // path has no parent, 0 is returned.
 138   size_t parent_path_end(StringRef path, Style style) {
 139     size_t end_pos = filename_pos(path, style);
 140
 141     bool filename_was_sep =
 142         path.size() > 0 && is_separator(path[end_pos], style);
 143
 144     // Skip separators until we reach root dir (or the start of the string).
 145     size_t root_dir_pos = root_dir_start(path, style);
 146     while (end_pos > 0 &&
 147            (root_dir_pos == StringRef::npos || end_pos > root_dir_pos) &&
 148            is_separator(path[end_pos - 1], style))
 149       --end_pos;
 150
 151     if (end_pos == root_dir_pos && !filename_was_sep) {
 152       // We've reached the root dir and the input path was *not* ending in a
 153       // sequence of slashes. Include the root dir in the parent path.
 154       return root_dir_pos + 1;
 155     }
 156
 157     // Otherwise, just include before the last slash.
 158     return end_pos;
 159   }
 160 } // end unnamed namespace
 161
 162 enum FSEntity {
 163   FS_Dir,
 164   FS_File,
 165   FS_Name
 166 };
 167
 168 static std::error_code
 169 createUniqueEntity(const Twine &Model, int &ResultFD,
 170                    SmallVectorImpl<char> &ResultPath, bool MakeAbsolute,
 171                    unsigned Mode, FSEntity Type,
 172                    sys::fs::OpenFlags Flags = sys::fs::OF_None) {
 173   SmallString<128> ModelStorage;
 174   Model.toVector(ModelStorage);
 175
 176   if (MakeAbsolute) {
 177     // Make model absolute by prepending a temp directory if it's not already.
 178     if (!sys::path::is_absolute(Twine(ModelStorage))) {
 179       SmallString<128> TDir;
 180       sys::path::system_temp_directory(true, TDir);
 181       sys::path::append(TDir, Twine(ModelStorage));
 182       ModelStorage.swap(TDir);
 183     }
 184   }
 185
 186   // From here on, DO NOT modify model. It may be needed if the randomly chosen
 187   // path already exists.
 188   ResultPath = ModelStorage;
 189   // Null terminate.
 190   ResultPath.push_back(0);
 191   ResultPath.pop_back();
 192
 193   // Limit the number of attempts we make, so that we don't infinite loop. E.g.
 194   // "permission denied" could be for a specific file (so we retry with a
 195   // different name) or for the whole directory (retry would always fail).
 196   // Checking which is racy, so we try a number of times, then give up.
 197   std::error_code EC;
 198   for (int Retries = 128; Retries > 0; --Retries) {
 199     // Replace '%' with random chars.
 200     for (unsigned i = 0, e = ModelStorage.size(); i != e; ++i) {
 201       if (ModelStorage[i] == '%')
 202         ResultPath[i] =
 203             "0123456789abcdef"[sys::Process::GetRandomNumber() & 15];
 204     }
 205
 206     // Try to open + create the file.
 207     switch (Type) {
 208     case FS_File: {
 209       EC = sys::fs::openFileForReadWrite(Twine(ResultPath.begin()), ResultFD,
 210                                          sys::fs::CD_CreateNew, Flags, Mode);
 211       if (EC) {
 212         // errc::permission_denied happens on Windows when we try to open a file
 213         // that has been marked for deletion.
 214         if (EC == errc::file_exists || EC == errc::permission_denied)
 215           continue;
 216         return EC;
 217       }
 218
 219       return std::error_code();
 220     }
 221
 222     case FS_Name: {
 223       EC = sys::fs::access(ResultPath.begin(), sys::fs::AccessMode::Exist);
 224       if (EC == errc::no_such_file_or_directory)
 225         return std::error_code();
 226       if (EC)
 227         return EC;
 228       continue;
 229     }
 230
 231     case FS_Dir: {
 232       EC = sys::fs::create_directory(ResultPath.begin(), false);
 233       if (EC) {
 234         if (EC == errc::file_exists)
 235           continue;
 236         return EC;
 237       }
 238       return std::error_code();
 239     }
 240     }
 241     llvm_unreachable("Invalid Type");
 242   }
 243   return EC;
 244 }
 245
 246 namespace llvm {
 247 namespace sys  {
 248 namespace path {
 249
 250 const_iterator begin(StringRef path, Style style) {
 251   const_iterator i;
 252   i.Path      = path;
 253   i.Component = find_first_component(path, style);
 254   i.Position  = 0;
 255   i.S = style;
 256   return i;
 257 }
 258
 259 const_iterator end(StringRef path) {
 260   const_iterator i;
 261   i.Path      = path;
 262   i.Position  = path.size();
 263   return i;
 264 }
 265
 266 const_iterator &const_iterator::operator++() {
 267   assert(Position < Path.size() && "Tried to increment past end!");
 268
 269   // Increment Position to past the current component
 270   Position += Component.size();
 271
 272   // Check for end.
 273   if (Position == Path.size()) {
 274     Component = StringRef();
 275     return *this;
 276   }
 277
 278   // Both POSIX and Windows treat paths that begin with exactly two separators
 279   // specially.
 280   bool was_net = Component.size() > 2 && is_separator(Component[0], S) &&
 281                  Component[1] == Component[0] && !is_separator(Component[2], S);
 282
 283   // Handle separators.
 284   if (is_separator(Path[Position], S)) {
 285     // Root dir.
 286     if (was_net ||
 287         // c:/
 288         (real_style(S) == Style::windows && Component.endswith(":"))) {
 289       Component = Path.substr(Position, 1);
 290       return *this;
 291     }
 292
 293     // Skip extra separators.
 294     while (Position != Path.size() && is_separator(Path[Position], S)) {
 295       ++Position;
 296     }
 297
 298     // Treat trailing '/' as a '.', unless it is the root dir.
 299     if (Position == Path.size() && Component != "/") {
 300       --Position;
 301       Component = ".";
 302       return *this;
 303     }
 304   }
 305
 306   // Find next component.
 307   size_t end_pos = Path.find_first_of(separators(S), Position);
 308   Component = Path.slice(Position, end_pos);
 309
 310   return *this;
 311 }
 312
 313 bool const_iterator::operator==(const const_iterator &RHS) const {
 314   return Path.begin() == RHS.Path.begin() && Position == RHS.Position;
 315 }
 316
 317 ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
 318   return Position - RHS.Position;
 319 }
 320
 321 reverse_iterator rbegin(StringRef Path, Style style) {
 322   reverse_iterator I;
 323   I.Path = Path;
 324   I.Position = Path.size();
 325   I.S = style;
 326   return ++I;
 327 }
 328
 329 reverse_iterator rend(StringRef Path) {
 330   reverse_iterator I;
 331   I.Path = Path;
 332   I.Component = Path.substr(0, 0);
 333   I.Position = 0;
 334   return I;
 335 }
 336
 337 reverse_iterator &reverse_iterator::operator++() {
 338   size_t root_dir_pos = root_dir_start(Path, S);
 339
 340   // Skip separators unless it's the root directory.
 341   size_t end_pos = Position;
 342   while (end_pos > 0 && (end_pos - 1) != root_dir_pos &&
 343          is_separator(Path[end_pos - 1], S))
 344     --end_pos;
 345
 346   // Treat trailing '/' as a '.', unless it is the root dir.
 347   if (Position == Path.size() && !Path.empty() &&
 348       is_separator(Path.back(), S) &&
 349       (root_dir_pos == StringRef::npos || end_pos - 1 > root_dir_pos)) {
 350     --Position;
 351     Component = ".";
 352     return *this;
 353   }
 354
 355   // Find next separator.
 356   size_t start_pos = filename_pos(Path.substr(0, end_pos), S);
 357   Component = Path.slice(start_pos, end_pos);
 358   Position = start_pos;
 359   return *this;
 360 }
 361
 362 bool reverse_iterator::operator==(const reverse_iterator &RHS) const {
 363   return Path.begin() == RHS.Path.begin() && Component == RHS.Component &&
 364          Position == RHS.Position;
 365 }
 366
 367 ptrdiff_t reverse_iterator::operator-(const reverse_iterator &RHS) const {
 368   return Position - RHS.Position;
 369 }
 370
 371 StringRef root_path(StringRef path, Style style) {
 372   const_iterator b = begin(path, style), pos = b, e = end(path);
 373   if (b != e) {
 374     bool has_net =
 375         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 376     bool has_drive = (real_style(style) == Style::windows) && b->endswith(":");
 377
 378     if (has_net || has_drive) {
 379       if ((++pos != e) && is_separator((*pos)[0], style)) {
 380         // {C:/,//net/}, so get the first two components.
 381         return path.substr(0, b->size() + pos->size());
 382       } else {
 383         // just {C:,//net}, return the first component.
 384         return *b;
 385       }
 386     }
 387
 388     // POSIX style root directory.
 389     if (is_separator((*b)[0], style)) {
 390       return *b;
 391     }
 392   }
 393
 394   return StringRef();
 395 }
 396
 397 StringRef root_name(StringRef path, Style style) {
 398   const_iterator b = begin(path, style), e = end(path);
 399   if (b != e) {
 400     bool has_net =
 401         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 402     bool has_drive = (real_style(style) == Style::windows) && b->endswith(":");
 403
 404     if (has_net || has_drive) {
 405       // just {C:,//net}, return the first component.
 406       return *b;
 407     }
 408   }
 409
 410   // No path or no name.
 411   return StringRef();
 412 }
 413
 414 StringRef root_directory(StringRef path, Style style) {
 415   const_iterator b = begin(path, style), pos = b, e = end(path);
 416   if (b != e) {
 417     bool has_net =
 418         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 419     bool has_drive = (real_style(style) == Style::windows) && b->endswith(":");
 420
 421     if ((has_net || has_drive) &&
 422         // {C:,//net}, skip to the next component.
 423         (++pos != e) && is_separator((*pos)[0], style)) {
 424       return *pos;
 425     }
 426
 427     // POSIX style root directory.
 428     if (!has_net && is_separator((*b)[0], style)) {
 429       return *b;
 430     }
 431   }
 432
 433   // No path or no root.
 434   return StringRef();
 435 }
 436
 437 StringRef relative_path(StringRef path, Style style) {
 438   StringRef root = root_path(path, style);
 439   return path.substr(root.size());
 440 }
 441
 442 void append(SmallVectorImpl<char> &path, Style style, const Twine &a,
 443             const Twine &b, const Twine &c, const Twine &d) {
 444   SmallString<32> a_storage;
 445   SmallString<32> b_storage;
 446   SmallString<32> c_storage;
 447   SmallString<32> d_storage;
 448
 449   SmallVector<StringRef, 4> components;
 450   if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
 451   if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
 452   if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
 453   if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
 454
 455   for (auto &component : components) {
 456     bool path_has_sep =
 457         !path.empty() && is_separator(path[path.size() - 1], style);
 458     if (path_has_sep) {
 459       // Strip separators from beginning of component.
 460       size_t loc = component.find_first_not_of(separators(style));
 461       StringRef c = component.substr(loc);
 462
 463       // Append it.
 464       path.append(c.begin(), c.end());
 465       continue;
 466     }
 467
 468     bool component_has_sep =
 469         !component.empty() && is_separator(component[0], style);
 470     if (!component_has_sep &&
 471         !(path.empty() || has_root_name(component, style))) {
 472       // Add a separator.
 473       path.push_back(preferred_separator(style));
 474     }
 475
 476     path.append(component.begin(), component.end());
 477   }
 478 }
 479
 480 void append(SmallVectorImpl<char> &path, const Twine &a, const Twine &b,
 481             const Twine &c, const Twine &d) {
 482   append(path, Style::native, a, b, c, d);
 483 }
 484
 485 void append(SmallVectorImpl<char> &path, const_iterator begin,
 486             const_iterator end, Style style) {
 487   for (; begin != end; ++begin)
 488     path::append(path, style, *begin);
 489 }
 490
 491 StringRef parent_path(StringRef path, Style style) {
 492   size_t end_pos = parent_path_end(path, style);
 493   if (end_pos == StringRef::npos)
 494     return StringRef();
 495   else
 496     return path.substr(0, end_pos);
 497 }
 498
 499 void remove_filename(SmallVectorImpl<char> &path, Style style) {
 500   size_t end_pos = parent_path_end(StringRef(path.begin(), path.size()), style);
 501   if (end_pos != StringRef::npos)
 502     path.set_size(end_pos);
 503 }
 504
 505 void replace_extension(SmallVectorImpl<char> &path, const Twine &extension,
 506                        Style style) {
 507   StringRef p(path.begin(), path.size());
 508   SmallString<32> ext_storage;
 509   StringRef ext = extension.toStringRef(ext_storage);
 510
 511   // Erase existing extension.
 512   size_t pos = p.find_last_of('.');
 513   if (pos != StringRef::npos && pos >= filename_pos(p, style))
 514     path.set_size(pos);
 515
 516   // Append '.' if needed.
 517   if (ext.size() > 0 && ext[0] != '.')
 518     path.push_back('.');
 519
 520   // Append extension.
 521   path.append(ext.begin(), ext.end());
 522 }
 523
 524 void replace_path_prefix(SmallVectorImpl<char> &Path,
 525                          const StringRef &OldPrefix, const StringRef &NewPrefix,
 526                          Style style) {
 527   if (OldPrefix.empty() && NewPrefix.empty())
 528     return;
 529
 530   StringRef OrigPath(Path.begin(), Path.size());
 531   if (!OrigPath.startswith(OldPrefix))
 532     return;
 533
 534   // If prefixes have the same size we can simply copy the new one over.
 535   if (OldPrefix.size() == NewPrefix.size()) {
 536     std::copy(NewPrefix.begin(), NewPrefix.end(), Path.begin());
 537     return;
 538   }
 539
 540   StringRef RelPath = OrigPath.substr(OldPrefix.size());
 541   SmallString<256> NewPath;
 542   path::append(NewPath, style, NewPrefix);
 543   path::append(NewPath, style, RelPath);
 544   Path.swap(NewPath);
 545 }
 546
 547 void native(const Twine &path, SmallVectorImpl<char> &result, Style style) {
 548   assert((!path.isSingleStringRef() ||
 549           path.getSingleStringRef().data() != result.data()) &&
 550          "path and result are not allowed to overlap!");
 551   // Clear result.
 552   result.clear();
 553   path.toVector(result);
 554   native(result, style);
 555 }
 556
 557 void native(SmallVectorImpl<char> &Path, Style style) {
 558   if (Path.empty())
 559     return;
 560   if (real_style(style) == Style::windows) {
 561     std::replace(Path.begin(), Path.end(), '/', '\\');
 562     if (Path[0] == '~' && (Path.size() == 1 || is_separator(Path[1], style))) {
 563       SmallString<128> PathHome;
 564       home_directory(PathHome);
 565       PathHome.append(Path.begin() + 1, Path.end());
 566       Path = PathHome;
 567     }
 568   } else {
 569     for (auto PI = Path.begin(), PE = Path.end(); PI < PE; ++PI) {
 570       if (*PI == '\\') {
 571         auto PN = PI + 1;
 572         if (PN < PE && *PN == '\\')
 573           ++PI; // increment once, the for loop will move over the escaped slash
 574         else
 575           *PI = '/';
 576       }
 577     }
 578   }
 579 }
 580
 581 std::string convert_to_slash(StringRef path, Style style) {
 582   if (real_style(style) != Style::windows)
 583     return path;
 584
 585   std::string s = path.str();
 586   std::replace(s.begin(), s.end(), '\\', '/');
 587   return s;
 588 }
 589
 590 StringRef filename(StringRef path, Style style) { return *rbegin(path, style); }
 591
 592 StringRef stem(StringRef path, Style style) {
 593   StringRef fname = filename(path, style);
 594   size_t pos = fname.find_last_of('.');
 595   if (pos == StringRef::npos)
 596     return fname;
 597   else
 598     if ((fname.size() == 1 && fname == ".") ||
 599         (fname.size() == 2 && fname == ".."))
 600       return fname;
 601     else
 602       return fname.substr(0, pos);
 603 }
 604
 605 StringRef extension(StringRef path, Style style) {
 606   StringRef fname = filename(path, style);
 607   size_t pos = fname.find_last_of('.');
 608   if (pos == StringRef::npos)
 609     return StringRef();
 610   else
 611     if ((fname.size() == 1 && fname == ".") ||
 612         (fname.size() == 2 && fname == ".."))
 613       return StringRef();
 614     else
 615       return fname.substr(pos);
 616 }
 617
 618 bool is_separator(char value, Style style) {
 619   if (value == '/')
 620     return true;
 621   if (real_style(style) == Style::windows)
 622     return value == '\\';
 623   return false;
 624 }
 625
 626 StringRef get_separator(Style style) {
 627   if (real_style(style) == Style::windows)
 628     return "\\";
 629   return "/";
 630 }
 631
 632 bool has_root_name(const Twine &path, Style style) {
 633   SmallString<128> path_storage;
 634   StringRef p = path.toStringRef(path_storage);
 635
 636   return !root_name(p, style).empty();
 637 }
 638
 639 bool has_root_directory(const Twine &path, Style style) {
 640   SmallString<128> path_storage;
 641   StringRef p = path.toStringRef(path_storage);
 642
 643   return !root_directory(p, style).empty();
 644 }
 645
 646 bool has_root_path(const Twine &path, Style style) {
 647   SmallString<128> path_storage;
 648   StringRef p = path.toStringRef(path_storage);
 649
 650   return !root_path(p, style).empty();
 651 }
 652
 653 bool has_relative_path(const Twine &path, Style style) {
 654   SmallString<128> path_storage;
 655   StringRef p = path.toStringRef(path_storage);
 656
 657   return !relative_path(p, style).empty();
 658 }
 659
 660 bool has_filename(const Twine &path, Style style) {
 661   SmallString<128> path_storage;
 662   StringRef p = path.toStringRef(path_storage);
 663
 664   return !filename(p, style).empty();
 665 }
 666
 667 bool has_parent_path(const Twine &path, Style style) {
 668   SmallString<128> path_storage;
 669   StringRef p = path.toStringRef(path_storage);
 670
 671   return !parent_path(p, style).empty();
 672 }
 673
 674 bool has_stem(const Twine &path, Style style) {
 675   SmallString<128> path_storage;
 676   StringRef p = path.toStringRef(path_storage);
 677
 678   return !stem(p, style).empty();
 679 }
 680
 681 bool has_extension(const Twine &path, Style style) {
 682   SmallString<128> path_storage;
 683   StringRef p = path.toStringRef(path_storage);
 684
 685   return !extension(p, style).empty();
 686 }
 687
 688 bool is_absolute(const Twine &path, Style style) {
 689   SmallString<128> path_storage;
 690   StringRef p = path.toStringRef(path_storage);
 691
 692   bool rootDir = has_root_directory(p, style);
 693   bool rootName =
 694       (real_style(style) != Style::windows) || has_root_name(p, style);
 695
 696   return rootDir && rootName;
 697 }
 698
 699 bool is_relative(const Twine &path, Style style) {
 700   return !is_absolute(path, style);
 701 }
 702
 703 StringRef 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 static SmallString<256> remove_dots(StringRef path, bool remove_dot_dot,
 714                                     Style style) {
 715   SmallVector<StringRef, 16> components;
 716
 717   // Skip the root path, then look for traversal in the components.
 718   StringRef rel = path::relative_path(path, style);
 719   for (StringRef C :
 720        llvm::make_range(path::begin(rel, style), path::end(rel))) {
 721     if (C == ".")
 722       continue;
 723     // Leading ".." will remain in the path unless it's at the root.
 724     if (remove_dot_dot && C == "..") {
 725       if (!components.empty() && components.back() != "..") {
 726         components.pop_back();
 727         continue;
 728       }
 729       if (path::is_absolute(path, style))
 730         continue;
 731     }
 732     components.push_back(C);
 733   }
 734
 735   SmallString<256> buffer = path::root_path(path, style);
 736   for (StringRef C : components)
 737     path::append(buffer, style, C);
 738   return buffer;
 739 }
 740
 741 bool remove_dots(SmallVectorImpl<char> &path, bool remove_dot_dot,
 742                  Style style) {
 743   StringRef p(path.data(), path.size());
 744
 745   SmallString<256> result = remove_dots(p, remove_dot_dot, style);
 746   if (result == path)
 747     return false;
 748
 749   path.swap(result);
 750   return true;
 751 }
 752
 753 } // end namespace path
 754
 755 namespace fs {
 756
 757 std::error_code getUniqueID(const Twine Path, UniqueID &Result) {
 758   file_status Status;
 759   std::error_code EC = status(Path, Status);
 760   if (EC)
 761     return EC;
 762   Result = Status.getUniqueID();
 763   return std::error_code();
 764 }
 765
 766 std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
 767                                  SmallVectorImpl<char> &ResultPath,
 768                                  unsigned Mode) {
 769   return createUniqueEntity(Model, ResultFd, ResultPath, false, Mode, FS_File);
 770 }
 771
 772 static std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
 773                                         SmallVectorImpl<char> &ResultPath,
 774                                         unsigned Mode, OpenFlags Flags) {
 775   return createUniqueEntity(Model, ResultFd, ResultPath, false, Mode, FS_File,
 776                             Flags);
 777 }
 778
 779 std::error_code createUniqueFile(const Twine &Model,
 780                                  SmallVectorImpl<char> &ResultPath,
 781                                  unsigned Mode) {
 782   int FD;
 783   auto EC = createUniqueFile(Model, FD, ResultPath, Mode);
 784   if (EC)
 785     return EC;
 786   // FD is only needed to avoid race conditions. Close it right away.
 787   close(FD);
 788   return EC;
 789 }
 790
 791 static std::error_code
 792 createTemporaryFile(const Twine &Model, int &ResultFD,
 793                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type) {
 794   SmallString<128> Storage;
 795   StringRef P = Model.toNullTerminatedStringRef(Storage);
 796   assert(P.find_first_of(separators(Style::native)) == StringRef::npos &&
 797          "Model must be a simple filename.");
 798   // Use P.begin() so that createUniqueEntity doesn't need to recreate Storage.
 799   return createUniqueEntity(P.begin(), ResultFD, ResultPath, true,
 800                             owner_read | owner_write, Type);
 801 }
 802
 803 static std::error_code
 804 createTemporaryFile(const Twine &Prefix, StringRef Suffix, int &ResultFD,
 805                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type) {
 806   const char *Middle = Suffix.empty() ? "-%%%%%%" : "-%%%%%%.";
 807   return createTemporaryFile(Prefix + Middle + Suffix, ResultFD, ResultPath,
 808                              Type);
 809 }
 810
 811 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 812                                     int &ResultFD,
 813                                     SmallVectorImpl<char> &ResultPath) {
 814   return createTemporaryFile(Prefix, Suffix, ResultFD, ResultPath, FS_File);
 815 }
 816
 817 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 818                                     SmallVectorImpl<char> &ResultPath) {
 819   int FD;
 820   auto EC = createTemporaryFile(Prefix, Suffix, FD, ResultPath);
 821   if (EC)
 822     return EC;
 823   // FD is only needed to avoid race conditions. Close it right away.
 824   close(FD);
 825   return EC;
 826 }
 827
 828
 829 // This is a mkdtemp with a different pattern. We use createUniqueEntity mostly
 830 // for consistency. We should try using mkdtemp.
 831 std::error_code createUniqueDirectory(const Twine &Prefix,
 832                                       SmallVectorImpl<char> &ResultPath) {
 833   int Dummy;
 834   return createUniqueEntity(Prefix + "-%%%%%%", Dummy, ResultPath, true, 0,
 835                             FS_Dir);
 836 }
 837
 838 std::error_code
 839 getPotentiallyUniqueFileName(const Twine &Model,
 840                              SmallVectorImpl<char> &ResultPath) {
 841   int Dummy;
 842   return createUniqueEntity(Model, Dummy, ResultPath, false, 0, FS_Name);
 843 }
 844
 845 std::error_code
 846 getPotentiallyUniqueTempFileName(const Twine &Prefix, StringRef Suffix,
 847                                  SmallVectorImpl<char> &ResultPath) {
 848   int Dummy;
 849   return createTemporaryFile(Prefix, Suffix, Dummy, ResultPath, FS_Name);
 850 }
 851
 852 static std::error_code make_absolute(const Twine &current_directory,
 853                                      SmallVectorImpl<char> &path,
 854                                      bool use_current_directory) {
 855   StringRef p(path.data(), path.size());
 856
 857   bool rootDirectory = path::has_root_directory(p);
 858   bool rootName =
 859       (real_style(Style::native) != Style::windows) || path::has_root_name(p);
 860
 861   // Already absolute.
 862   if (rootName && rootDirectory)
 863     return std::error_code();
 864
 865   // All of the following conditions will need the current directory.
 866   SmallString<128> current_dir;
 867   if (use_current_directory)
 868     current_directory.toVector(current_dir);
 869   else if (std::error_code ec = current_path(current_dir))
 870     return ec;
 871
 872   // Relative path. Prepend the current directory.
 873   if (!rootName && !rootDirectory) {
 874     // Append path to the current directory.
 875     path::append(current_dir, p);
 876     // Set path to the result.
 877     path.swap(current_dir);
 878     return std::error_code();
 879   }
 880
 881   if (!rootName && rootDirectory) {
 882     StringRef cdrn = path::root_name(current_dir);
 883     SmallString<128> curDirRootName(cdrn.begin(), cdrn.end());
 884     path::append(curDirRootName, p);
 885     // Set path to the result.
 886     path.swap(curDirRootName);
 887     return std::error_code();
 888   }
 889
 890   if (rootName && !rootDirectory) {
 891     StringRef pRootName      = path::root_name(p);
 892     StringRef bRootDirectory = path::root_directory(current_dir);
 893     StringRef bRelativePath  = path::relative_path(current_dir);
 894     StringRef pRelativePath  = path::relative_path(p);
 895
 896     SmallString<128> res;
 897     path::append(res, pRootName, bRootDirectory, bRelativePath, pRelativePath);
 898     path.swap(res);
 899     return std::error_code();
 900   }
 901
 902   llvm_unreachable("All rootName and rootDirectory combinations should have "
 903                    "occurred above!");
 904 }
 905
 906 std::error_code make_absolute(const Twine &current_directory,
 907                               SmallVectorImpl<char> &path) {
 908   return make_absolute(current_directory, path, true);
 909 }
 910
 911 std::error_code make_absolute(SmallVectorImpl<char> &path) {
 912   return make_absolute(Twine(), path, false);
 913 }
 914
 915 std::error_code create_directories(const Twine &Path, bool IgnoreExisting,
 916                                    perms Perms) {
 917   SmallString<128> PathStorage;
 918   StringRef P = Path.toStringRef(PathStorage);
 919
 920   // Be optimistic and try to create the directory
 921   std::error_code EC = create_directory(P, IgnoreExisting, Perms);
 922   // If we succeeded, or had any error other than the parent not existing, just
 923   // return it.
 924   if (EC != errc::no_such_file_or_directory)
 925     return EC;
 926
 927   // We failed because of a no_such_file_or_directory, try to create the
 928   // parent.
 929   StringRef Parent = path::parent_path(P);
 930   if (Parent.empty())
 931     return EC;
 932
 933   if ((EC = create_directories(Parent, IgnoreExisting, Perms)))
 934       return EC;
 935
 936   return create_directory(P, IgnoreExisting, Perms);
 937 }
 938
 939 static std::error_code copy_file_internal(int ReadFD, int WriteFD) {
 940   const size_t BufSize = 4096;
 941   char *Buf = new char[BufSize];
 942   int BytesRead = 0, BytesWritten = 0;
 943   for (;;) {
 944     BytesRead = read(ReadFD, Buf, BufSize);
 945     if (BytesRead <= 0)
 946       break;
 947     while (BytesRead) {
 948       BytesWritten = write(WriteFD, Buf, BytesRead);
 949       if (BytesWritten < 0)
 950         break;
 951       BytesRead -= BytesWritten;
 952     }
 953     if (BytesWritten < 0)
 954       break;
 955   }
 956   delete[] Buf;
 957
 958   if (BytesRead < 0 || BytesWritten < 0)
 959     return std::error_code(errno, std::generic_category());
 960   return std::error_code();
 961 }
 962
 963 std::error_code copy_file(const Twine &From, const Twine &To) {
 964   int ReadFD, WriteFD;
 965   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
 966     return EC;
 967   if (std::error_code EC =
 968           openFileForWrite(To, WriteFD, CD_CreateAlways, OF_None)) {
 969     close(ReadFD);
 970     return EC;
 971   }
 972
 973   std::error_code EC = copy_file_internal(ReadFD, WriteFD);
 974
 975   close(ReadFD);
 976   close(WriteFD);
 977
 978   return EC;
 979 }
 980
 981 std::error_code copy_file(const Twine &From, int ToFD) {
 982   int ReadFD;
 983   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
 984     return EC;
 985
 986   std::error_code EC = copy_file_internal(ReadFD, ToFD);
 987
 988   close(ReadFD);
 989
 990   return EC;
 991 }
 992
 993 ErrorOr<MD5::MD5Result> md5_contents(int FD) {
 994   MD5 Hash;
 995
 996   constexpr size_t BufSize = 4096;
 997   std::vector<uint8_t> Buf(BufSize);
 998   int BytesRead = 0;
 999   for (;;) {
1000     BytesRead = read(FD, Buf.data(), BufSize);
1001     if (BytesRead <= 0)
1002       break;
1003     Hash.update(makeArrayRef(Buf.data(), BytesRead));
1004   }
1005
1006   if (BytesRead < 0)
1007     return std::error_code(errno, std::generic_category());
1008   MD5::MD5Result Result;
1009   Hash.final(Result);
1010   return Result;
1011 }
1012
1013 ErrorOr<MD5::MD5Result> md5_contents(const Twine &Path) {
1014   int FD;
1015   if (auto EC = openFileForRead(Path, FD, OF_None))
1016     return EC;
1017
1018   auto Result = md5_contents(FD);
1019   close(FD);
1020   return Result;
1021 }
1022
1023 bool exists(const basic_file_status &status) {
1024   return status_known(status) && status.type() != file_type::file_not_found;
1025 }
1026
1027 bool status_known(const basic_file_status &s) {
1028   return s.type() != file_type::status_error;
1029 }
1030
1031 file_type get_file_type(const Twine &Path, bool Follow) {
1032   file_status st;
1033   if (status(Path, st, Follow))
1034     return file_type::status_error;
1035   return st.type();
1036 }
1037
1038 bool is_directory(const basic_file_status &status) {
1039   return status.type() == file_type::directory_file;
1040 }
1041
1042 std::error_code is_directory(const Twine &path, bool &result) {
1043   file_status st;
1044   if (std::error_code ec = status(path, st))
1045     return ec;
1046   result = is_directory(st);
1047   return std::error_code();
1048 }
1049
1050 bool is_regular_file(const basic_file_status &status) {
1051   return status.type() == file_type::regular_file;
1052 }
1053
1054 std::error_code is_regular_file(const Twine &path, bool &result) {
1055   file_status st;
1056   if (std::error_code ec = status(path, st))
1057     return ec;
1058   result = is_regular_file(st);
1059   return std::error_code();
1060 }
1061
1062 bool is_symlink_file(const basic_file_status &status) {
1063   return status.type() == file_type::symlink_file;
1064 }
1065
1066 std::error_code is_symlink_file(const Twine &path, bool &result) {
1067   file_status st;
1068   if (std::error_code ec = status(path, st, false))
1069     return ec;
1070   result = is_symlink_file(st);
1071   return std::error_code();
1072 }
1073
1074 bool is_other(const basic_file_status &status) {
1075   return exists(status) &&
1076          !is_regular_file(status) &&
1077          !is_directory(status);
1078 }
1079
1080 std::error_code is_other(const Twine &Path, bool &Result) {
1081   file_status FileStatus;
1082   if (std::error_code EC = status(Path, FileStatus))
1083     return EC;
1084   Result = is_other(FileStatus);
1085   return std::error_code();
1086 }
1087
1088 void directory_entry::replace_filename(const Twine &Filename, file_type Type,
1089                                        basic_file_status Status) {
1090   SmallString<128> PathStr = path::parent_path(Path);
1091   path::append(PathStr, Filename);
1092   this->Path = PathStr.str();
1093   this->Type = Type;
1094   this->Status = Status;
1095 }
1096
1097 ErrorOr<perms> getPermissions(const Twine &Path) {
1098   file_status Status;
1099   if (std::error_code EC = status(Path, Status))
1100     return EC;
1101
1102   return Status.permissions();
1103 }
1104
1105 } // end namespace fs
1106 } // end namespace sys
1107 } // end namespace llvm
1108
1109 // Include the truly platform-specific parts.
1110 #if defined(LLVM_ON_UNIX)
1111 #include "Unix/Path.inc"
1112 #endif
1113 #if defined(_WIN32)
1114 #include "Windows/Path.inc"
1115 #endif
1116
1117 namespace llvm {
1118 namespace sys {
1119 namespace fs {
1120 TempFile::TempFile(StringRef Name, int FD) : TmpName(Name), FD(FD) {}
1121 TempFile::TempFile(TempFile &&Other) { *this = std::move(Other); }
1122 TempFile &TempFile::operator=(TempFile &&Other) {
1123   TmpName = std::move(Other.TmpName);
1124   FD = Other.FD;
1125   Other.Done = true;
1126   return *this;
1127 }
1128
1129 TempFile::~TempFile() { assert(Done); }
1130
1131 Error TempFile::discard() {
1132   Done = true;
1133   std::error_code RemoveEC;
1134 // On windows closing will remove the file.
1135 #ifndef _WIN32
1136   // Always try to close and remove.
1137   if (!TmpName.empty()) {
1138     RemoveEC = fs::remove(TmpName);
1139     sys::DontRemoveFileOnSignal(TmpName);
1140   }
1141 #endif
1142
1143   if (!RemoveEC)
1144     TmpName = "";
1145
1146   if (FD != -1 && close(FD) == -1) {
1147     std::error_code EC = std::error_code(errno, std::generic_category());
1148     return errorCodeToError(EC);
1149   }
1150   FD = -1;
1151
1152   return errorCodeToError(RemoveEC);
1153 }
1154
1155 Error TempFile::keep(const Twine &Name) {
1156   assert(!Done);
1157   Done = true;
1158   // Always try to close and rename.
1159 #ifdef _WIN32
1160   // If we can't cancel the delete don't rename.
1161   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1162   std::error_code RenameEC = setDeleteDisposition(H, false);
1163   if (!RenameEC) {
1164     RenameEC = rename_fd(FD, Name);
1165     // If rename failed because it's cross-device, copy instead
1166     if (RenameEC ==
1167       std::error_code(ERROR_NOT_SAME_DEVICE, std::system_category())) {
1168       RenameEC = copy_file(TmpName, Name);
1169       setDeleteDisposition(H, true);
1170     }
1171   }
1172
1173   // If we can't rename, discard the temporary file.
1174   if (RenameEC)
1175     setDeleteDisposition(H, true);
1176 #else
1177   std::error_code RenameEC = fs::rename(TmpName, Name);
1178   if (RenameEC) {
1179     // If we can't rename, try to copy to work around cross-device link issues.
1180     RenameEC = sys::fs::copy_file(TmpName, Name);
1181     // If we can't rename or copy, discard the temporary file.
1182     if (RenameEC)
1183       remove(TmpName);
1184   }
1185   sys::DontRemoveFileOnSignal(TmpName);
1186 #endif
1187
1188   if (!RenameEC)
1189     TmpName = "";
1190
1191   if (close(FD) == -1) {
1192     std::error_code EC(errno, std::generic_category());
1193     return errorCodeToError(EC);
1194   }
1195   FD = -1;
1196
1197   return errorCodeToError(RenameEC);
1198 }
1199
1200 Error TempFile::keep() {
1201   assert(!Done);
1202   Done = true;
1203
1204 #ifdef _WIN32
1205   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1206   if (std::error_code EC = setDeleteDisposition(H, false))
1207     return errorCodeToError(EC);
1208 #else
1209   sys::DontRemoveFileOnSignal(TmpName);
1210 #endif
1211
1212   TmpName = "";
1213
1214   if (close(FD) == -1) {
1215     std::error_code EC(errno, std::generic_category());
1216     return errorCodeToError(EC);
1217   }
1218   FD = -1;
1219
1220   return Error::success();
1221 }
1222
1223 Expected<TempFile> TempFile::create(const Twine &Model, unsigned Mode) {
1224   int FD;
1225   SmallString<128> ResultPath;
1226   if (std::error_code EC =
1227           createUniqueFile(Model, FD, ResultPath, Mode, OF_Delete))
1228     return errorCodeToError(EC);
1229
1230   TempFile Ret(ResultPath, FD);
1231 #ifndef _WIN32
1232   if (sys::RemoveFileOnSignal(ResultPath)) {
1233     // Make sure we delete the file when RemoveFileOnSignal fails.
1234     consumeError(Ret.discard());
1235     std::error_code EC(errc::operation_not_permitted);
1236     return errorCodeToError(EC);
1237   }
1238 #endif
1239   return std::move(Ret);
1240 }
1241 }
1242
1243 namespace path {
1244
1245 bool user_cache_directory(SmallVectorImpl<char> &Result, const Twine &Path1,
1246                           const Twine &Path2, const Twine &Path3) {
1247   if (getUserCacheDir(Result)) {
1248     append(Result, Path1, Path2, Path3);
1249     return true;
1250   }
1251   return false;
1252 }
1253
1254 } // end namespace path
1255 } // end namsspace sys
1256 } // end namespace llvm