llvm/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                    FSEntity Type, sys::fs::OpenFlags Flags = sys::fs::OF_None,
 171                    unsigned Mode = 0) {
 172
 173   // Limit the number of attempts we make, so that we don't infinite loop. E.g.
 174   // "permission denied" could be for a specific file (so we retry with a
 175   // different name) or for the whole directory (retry would always fail).
 176   // Checking which is racy, so we try a number of times, then give up.
 177   std::error_code EC;
 178   for (int Retries = 128; Retries > 0; --Retries) {
 179     sys::fs::createUniquePath(Model, ResultPath, MakeAbsolute);
 180     // Try to open + create the file.
 181     switch (Type) {
 182     case FS_File: {
 183       EC = sys::fs::openFileForReadWrite(Twine(ResultPath.begin()), ResultFD,
 184                                          sys::fs::CD_CreateNew, Flags, Mode);
 185       if (EC) {
 186         // errc::permission_denied happens on Windows when we try to open a file
 187         // that has been marked for deletion.
 188         if (EC == errc::file_exists || EC == errc::permission_denied)
 189           continue;
 190         return EC;
 191       }
 192
 193       return std::error_code();
 194     }
 195
 196     case FS_Name: {
 197       EC = sys::fs::access(ResultPath.begin(), sys::fs::AccessMode::Exist);
 198       if (EC == errc::no_such_file_or_directory)
 199         return std::error_code();
 200       if (EC)
 201         return EC;
 202       continue;
 203     }
 204
 205     case FS_Dir: {
 206       EC = sys::fs::create_directory(ResultPath.begin(), false);
 207       if (EC) {
 208         if (EC == errc::file_exists)
 209           continue;
 210         return EC;
 211       }
 212       return std::error_code();
 213     }
 214     }
 215     llvm_unreachable("Invalid Type");
 216   }
 217   return EC;
 218 }
 219
 220 namespace llvm {
 221 namespace sys  {
 222 namespace path {
 223
 224 const_iterator begin(StringRef path, Style style) {
 225   const_iterator i;
 226   i.Path      = path;
 227   i.Component = find_first_component(path, style);
 228   i.Position  = 0;
 229   i.S = style;
 230   return i;
 231 }
 232
 233 const_iterator end(StringRef path) {
 234   const_iterator i;
 235   i.Path      = path;
 236   i.Position  = path.size();
 237   return i;
 238 }
 239
 240 const_iterator &const_iterator::operator++() {
 241   assert(Position < Path.size() && "Tried to increment past end!");
 242
 243   // Increment Position to past the current component
 244   Position += Component.size();
 245
 246   // Check for end.
 247   if (Position == Path.size()) {
 248     Component = StringRef();
 249     return *this;
 250   }
 251
 252   // Both POSIX and Windows treat paths that begin with exactly two separators
 253   // specially.
 254   bool was_net = Component.size() > 2 && is_separator(Component[0], S) &&
 255                  Component[1] == Component[0] && !is_separator(Component[2], S);
 256
 257   // Handle separators.
 258   if (is_separator(Path[Position], S)) {
 259     // Root dir.
 260     if (was_net ||
 261         // c:/
 262         (real_style(S) == Style::windows && Component.endswith(":"))) {
 263       Component = Path.substr(Position, 1);
 264       return *this;
 265     }
 266
 267     // Skip extra separators.
 268     while (Position != Path.size() && is_separator(Path[Position], S)) {
 269       ++Position;
 270     }
 271
 272     // Treat trailing '/' as a '.', unless it is the root dir.
 273     if (Position == Path.size() && Component != "/") {
 274       --Position;
 275       Component = ".";
 276       return *this;
 277     }
 278   }
 279
 280   // Find next component.
 281   size_t end_pos = Path.find_first_of(separators(S), Position);
 282   Component = Path.slice(Position, end_pos);
 283
 284   return *this;
 285 }
 286
 287 bool const_iterator::operator==(const const_iterator &RHS) const {
 288   return Path.begin() == RHS.Path.begin() && Position == RHS.Position;
 289 }
 290
 291 ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
 292   return Position - RHS.Position;
 293 }
 294
 295 reverse_iterator rbegin(StringRef Path, Style style) {
 296   reverse_iterator I;
 297   I.Path = Path;
 298   I.Position = Path.size();
 299   I.S = style;
 300   ++I;
 301   return I;
 302 }
 303
 304 reverse_iterator rend(StringRef Path) {
 305   reverse_iterator I;
 306   I.Path = Path;
 307   I.Component = Path.substr(0, 0);
 308   I.Position = 0;
 309   return I;
 310 }
 311
 312 reverse_iterator &reverse_iterator::operator++() {
 313   size_t root_dir_pos = root_dir_start(Path, S);
 314
 315   // Skip separators unless it's the root directory.
 316   size_t end_pos = Position;
 317   while (end_pos > 0 && (end_pos - 1) != root_dir_pos &&
 318          is_separator(Path[end_pos - 1], S))
 319     --end_pos;
 320
 321   // Treat trailing '/' as a '.', unless it is the root dir.
 322   if (Position == Path.size() && !Path.empty() &&
 323       is_separator(Path.back(), S) &&
 324       (root_dir_pos == StringRef::npos || end_pos - 1 > root_dir_pos)) {
 325     --Position;
 326     Component = ".";
 327     return *this;
 328   }
 329
 330   // Find next separator.
 331   size_t start_pos = filename_pos(Path.substr(0, end_pos), S);
 332   Component = Path.slice(start_pos, end_pos);
 333   Position = start_pos;
 334   return *this;
 335 }
 336
 337 bool reverse_iterator::operator==(const reverse_iterator &RHS) const {
 338   return Path.begin() == RHS.Path.begin() && Component == RHS.Component &&
 339          Position == RHS.Position;
 340 }
 341
 342 ptrdiff_t reverse_iterator::operator-(const reverse_iterator &RHS) const {
 343   return Position - RHS.Position;
 344 }
 345
 346 StringRef root_path(StringRef path, Style style) {
 347   const_iterator b = begin(path, style), pos = b, e = end(path);
 348   if (b != e) {
 349     bool has_net =
 350         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 351     bool has_drive = (real_style(style) == Style::windows) && b->endswith(":");
 352
 353     if (has_net || has_drive) {
 354       if ((++pos != e) && is_separator((*pos)[0], style)) {
 355         // {C:/,//net/}, so get the first two components.
 356         return path.substr(0, b->size() + pos->size());
 357       }
 358       // just {C:,//net}, return the first component.
 359       return *b;
 360     }
 361
 362     // POSIX style root directory.
 363     if (is_separator((*b)[0], style)) {
 364       return *b;
 365     }
 366   }
 367
 368   return StringRef();
 369 }
 370
 371 StringRef root_name(StringRef path, Style style) {
 372   const_iterator b = begin(path, style), 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       // just {C:,//net}, return the first component.
 380       return *b;
 381     }
 382   }
 383
 384   // No path or no name.
 385   return StringRef();
 386 }
 387
 388 StringRef root_directory(StringRef path, Style style) {
 389   const_iterator b = begin(path, style), pos = b, e = end(path);
 390   if (b != e) {
 391     bool has_net =
 392         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 393     bool has_drive = (real_style(style) == Style::windows) && b->endswith(":");
 394
 395     if ((has_net || has_drive) &&
 396         // {C:,//net}, skip to the next component.
 397         (++pos != e) && is_separator((*pos)[0], style)) {
 398       return *pos;
 399     }
 400
 401     // POSIX style root directory.
 402     if (!has_net && is_separator((*b)[0], style)) {
 403       return *b;
 404     }
 405   }
 406
 407   // No path or no root.
 408   return StringRef();
 409 }
 410
 411 StringRef relative_path(StringRef path, Style style) {
 412   StringRef root = root_path(path, style);
 413   return path.substr(root.size());
 414 }
 415
 416 void append(SmallVectorImpl<char> &path, Style style, const Twine &a,
 417             const Twine &b, const Twine &c, const Twine &d) {
 418   SmallString<32> a_storage;
 419   SmallString<32> b_storage;
 420   SmallString<32> c_storage;
 421   SmallString<32> d_storage;
 422
 423   SmallVector<StringRef, 4> components;
 424   if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
 425   if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
 426   if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
 427   if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
 428
 429   for (auto &component : components) {
 430     bool path_has_sep =
 431         !path.empty() && is_separator(path[path.size() - 1], style);
 432     if (path_has_sep) {
 433       // Strip separators from beginning of component.
 434       size_t loc = component.find_first_not_of(separators(style));
 435       StringRef c = component.substr(loc);
 436
 437       // Append it.
 438       path.append(c.begin(), c.end());
 439       continue;
 440     }
 441
 442     bool component_has_sep =
 443         !component.empty() && is_separator(component[0], style);
 444     if (!component_has_sep &&
 445         !(path.empty() || has_root_name(component, style))) {
 446       // Add a separator.
 447       path.push_back(preferred_separator(style));
 448     }
 449
 450     path.append(component.begin(), component.end());
 451   }
 452 }
 453
 454 void append(SmallVectorImpl<char> &path, const Twine &a, const Twine &b,
 455             const Twine &c, const Twine &d) {
 456   append(path, Style::native, a, b, c, d);
 457 }
 458
 459 void append(SmallVectorImpl<char> &path, const_iterator begin,
 460             const_iterator end, Style style) {
 461   for (; begin != end; ++begin)
 462     path::append(path, style, *begin);
 463 }
 464
 465 StringRef parent_path(StringRef path, Style style) {
 466   size_t end_pos = parent_path_end(path, style);
 467   if (end_pos == StringRef::npos)
 468     return StringRef();
 469   return path.substr(0, end_pos);
 470 }
 471
 472 void remove_filename(SmallVectorImpl<char> &path, Style style) {
 473   size_t end_pos = parent_path_end(StringRef(path.begin(), path.size()), style);
 474   if (end_pos != StringRef::npos)
 475     path.set_size(end_pos);
 476 }
 477
 478 void replace_extension(SmallVectorImpl<char> &path, const Twine &extension,
 479                        Style style) {
 480   StringRef p(path.begin(), path.size());
 481   SmallString<32> ext_storage;
 482   StringRef ext = extension.toStringRef(ext_storage);
 483
 484   // Erase existing extension.
 485   size_t pos = p.find_last_of('.');
 486   if (pos != StringRef::npos && pos >= filename_pos(p, style))
 487     path.set_size(pos);
 488
 489   // Append '.' if needed.
 490   if (ext.size() > 0 && ext[0] != '.')
 491     path.push_back('.');
 492
 493   // Append extension.
 494   path.append(ext.begin(), ext.end());
 495 }
 496
 497 static bool starts_with(StringRef Path, StringRef Prefix,
 498                         Style style = Style::native) {
 499   // Windows prefix matching : case and separator insensitive
 500   if (real_style(style) == Style::windows) {
 501     if (Path.size() < Prefix.size())
 502       return false;
 503     for (size_t I = 0, E = Prefix.size(); I != E; ++I) {
 504       bool SepPath = is_separator(Path[I], style);
 505       bool SepPrefix = is_separator(Prefix[I], style);
 506       if (SepPath != SepPrefix)
 507         return false;
 508       if (!SepPath && toLower(Path[I]) != toLower(Prefix[I]))
 509         return false;
 510     }
 511     return true;
 512   }
 513   return Path.startswith(Prefix);
 514 }
 515
 516 bool replace_path_prefix(SmallVectorImpl<char> &Path, StringRef OldPrefix,
 517                          StringRef NewPrefix, Style style) {
 518   if (OldPrefix.empty() && NewPrefix.empty())
 519     return false;
 520
 521   StringRef OrigPath(Path.begin(), Path.size());
 522   if (!starts_with(OrigPath, OldPrefix, style))
 523     return false;
 524
 525   // If prefixes have the same size we can simply copy the new one over.
 526   if (OldPrefix.size() == NewPrefix.size()) {
 527     llvm::copy(NewPrefix, Path.begin());
 528     return true;
 529   }
 530
 531   StringRef RelPath = OrigPath.substr(OldPrefix.size());
 532   SmallString<256> NewPath;
 533   (Twine(NewPrefix) + RelPath).toVector(NewPath);
 534   Path.swap(NewPath);
 535   return true;
 536 }
 537
 538 void native(const Twine &path, SmallVectorImpl<char> &result, Style style) {
 539   assert((!path.isSingleStringRef() ||
 540           path.getSingleStringRef().data() != result.data()) &&
 541          "path and result are not allowed to overlap!");
 542   // Clear result.
 543   result.clear();
 544   path.toVector(result);
 545   native(result, style);
 546 }
 547
 548 void native(SmallVectorImpl<char> &Path, Style style) {
 549   if (Path.empty())
 550     return;
 551   if (real_style(style) == Style::windows) {
 552     std::replace(Path.begin(), Path.end(), '/', '\\');
 553     if (Path[0] == '~' && (Path.size() == 1 || is_separator(Path[1], style))) {
 554       SmallString<128> PathHome;
 555       home_directory(PathHome);
 556       PathHome.append(Path.begin() + 1, Path.end());
 557       Path = PathHome;
 558     }
 559   } else {
 560     for (auto PI = Path.begin(), PE = Path.end(); PI < PE; ++PI)
 561       if (*PI == '\\')
 562         *PI = '/';
 563   }
 564 }
 565
 566 std::string convert_to_slash(StringRef path, Style style) {
 567   if (real_style(style) != Style::windows)
 568     return std::string(path);
 569
 570   std::string s = path.str();
 571   std::replace(s.begin(), s.end(), '\\', '/');
 572   return s;
 573 }
 574
 575 StringRef filename(StringRef path, Style style) { return *rbegin(path, style); }
 576
 577 StringRef stem(StringRef path, Style style) {
 578   StringRef fname = filename(path, style);
 579   size_t pos = fname.find_last_of('.');
 580   if (pos == StringRef::npos)
 581     return fname;
 582   if ((fname.size() == 1 && fname == ".") ||
 583       (fname.size() == 2 && fname == ".."))
 584     return fname;
 585   return fname.substr(0, pos);
 586 }
 587
 588 StringRef extension(StringRef path, Style style) {
 589   StringRef fname = filename(path, style);
 590   size_t pos = fname.find_last_of('.');
 591   if (pos == StringRef::npos)
 592     return StringRef();
 593   if ((fname.size() == 1 && fname == ".") ||
 594       (fname.size() == 2 && fname == ".."))
 595     return StringRef();
 596   return fname.substr(pos);
 597 }
 598
 599 bool is_separator(char value, Style style) {
 600   if (value == '/')
 601     return true;
 602   if (real_style(style) == Style::windows)
 603     return value == '\\';
 604   return false;
 605 }
 606
 607 StringRef get_separator(Style style) {
 608   if (real_style(style) == Style::windows)
 609     return "\\";
 610   return "/";
 611 }
 612
 613 bool has_root_name(const Twine &path, Style style) {
 614   SmallString<128> path_storage;
 615   StringRef p = path.toStringRef(path_storage);
 616
 617   return !root_name(p, style).empty();
 618 }
 619
 620 bool has_root_directory(const Twine &path, Style style) {
 621   SmallString<128> path_storage;
 622   StringRef p = path.toStringRef(path_storage);
 623
 624   return !root_directory(p, style).empty();
 625 }
 626
 627 bool has_root_path(const Twine &path, Style style) {
 628   SmallString<128> path_storage;
 629   StringRef p = path.toStringRef(path_storage);
 630
 631   return !root_path(p, style).empty();
 632 }
 633
 634 bool has_relative_path(const Twine &path, Style style) {
 635   SmallString<128> path_storage;
 636   StringRef p = path.toStringRef(path_storage);
 637
 638   return !relative_path(p, style).empty();
 639 }
 640
 641 bool has_filename(const Twine &path, Style style) {
 642   SmallString<128> path_storage;
 643   StringRef p = path.toStringRef(path_storage);
 644
 645   return !filename(p, style).empty();
 646 }
 647
 648 bool has_parent_path(const Twine &path, Style style) {
 649   SmallString<128> path_storage;
 650   StringRef p = path.toStringRef(path_storage);
 651
 652   return !parent_path(p, style).empty();
 653 }
 654
 655 bool has_stem(const Twine &path, Style style) {
 656   SmallString<128> path_storage;
 657   StringRef p = path.toStringRef(path_storage);
 658
 659   return !stem(p, style).empty();
 660 }
 661
 662 bool has_extension(const Twine &path, Style style) {
 663   SmallString<128> path_storage;
 664   StringRef p = path.toStringRef(path_storage);
 665
 666   return !extension(p, style).empty();
 667 }
 668
 669 bool is_absolute(const Twine &path, Style style) {
 670   SmallString<128> path_storage;
 671   StringRef p = path.toStringRef(path_storage);
 672
 673   bool rootDir = has_root_directory(p, style);
 674   bool rootName =
 675       (real_style(style) != Style::windows) || has_root_name(p, style);
 676
 677   return rootDir && rootName;
 678 }
 679
 680 bool is_absolute_gnu(const Twine &path, Style style) {
 681   SmallString<128> path_storage;
 682   StringRef p = path.toStringRef(path_storage);
 683
 684   // Handle '/' which is absolute for both Windows and POSIX systems.
 685   // Handle '\\' on Windows.
 686   if (!p.empty() && is_separator(p.front(), style))
 687     return true;
 688
 689   if (real_style(style) == Style::windows) {
 690     // Handle drive letter pattern (a character followed by ':') on Windows.
 691     if (p.size() >= 2 && (p[0] && p[1] == ':'))
 692       return true;
 693   }
 694
 695   return false;
 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 // Remove path traversal components ("." and "..") when possible, and
 713 // canonicalize slashes.
 714 bool remove_dots(SmallVectorImpl<char> &the_path, bool remove_dot_dot,
 715                  Style style) {
 716   style = real_style(style);
 717   StringRef remaining(the_path.data(), the_path.size());
 718   bool needs_change = false;
 719   SmallVector<StringRef, 16> components;
 720
 721   // Consume the root path, if present.
 722   StringRef root = path::root_path(remaining, style);
 723   bool absolute = !root.empty();
 724   if (absolute)
 725     remaining = remaining.drop_front(root.size());
 726
 727   // Loop over path components manually. This makes it easier to detect
 728   // non-preferred slashes and double separators that must be canonicalized.
 729   while (!remaining.empty()) {
 730     size_t next_slash = remaining.find_first_of(separators(style));
 731     if (next_slash == StringRef::npos)
 732       next_slash = remaining.size();
 733     StringRef component = remaining.take_front(next_slash);
 734     remaining = remaining.drop_front(next_slash);
 735
 736     // Eat the slash, and check if it is the preferred separator.
 737     if (!remaining.empty()) {
 738       needs_change |= remaining.front() != preferred_separator(style);
 739       remaining = remaining.drop_front();
 740       // The path needs to be rewritten if it has a trailing slash.
 741       // FIXME: This is emergent behavior that could be removed.
 742       needs_change |= remaining.empty();
 743     }
 744
 745     // Check for path traversal components or double separators.
 746     if (component.empty() || component == ".") {
 747       needs_change = true;
 748     } else if (remove_dot_dot && component == "..") {
 749       needs_change = true;
 750       // Do not allow ".." to remove the root component. If this is the
 751       // beginning of a relative path, keep the ".." component.
 752       if (!components.empty() && components.back() != "..") {
 753         components.pop_back();
 754       } else if (!absolute) {
 755         components.push_back(component);
 756       }
 757     } else {
 758       components.push_back(component);
 759     }
 760   }
 761
 762   // Avoid rewriting the path unless we have to.
 763   if (!needs_change)
 764     return false;
 765
 766   SmallString<256> buffer = root;
 767   if (!components.empty()) {
 768     buffer += components[0];
 769     for (StringRef C : makeArrayRef(components).drop_front()) {
 770       buffer += preferred_separator(style);
 771       buffer += C;
 772     }
 773   }
 774   the_path.swap(buffer);
 775   return true;
 776 }
 777
 778 } // end namespace path
 779
 780 namespace fs {
 781
 782 std::error_code getUniqueID(const Twine Path, UniqueID &Result) {
 783   file_status Status;
 784   std::error_code EC = status(Path, Status);
 785   if (EC)
 786     return EC;
 787   Result = Status.getUniqueID();
 788   return std::error_code();
 789 }
 790
 791 void createUniquePath(const Twine &Model, SmallVectorImpl<char> &ResultPath,
 792                       bool MakeAbsolute) {
 793   SmallString<128> ModelStorage;
 794   Model.toVector(ModelStorage);
 795
 796   if (MakeAbsolute) {
 797     // Make model absolute by prepending a temp directory if it's not already.
 798     if (!sys::path::is_absolute(Twine(ModelStorage))) {
 799       SmallString<128> TDir;
 800       sys::path::system_temp_directory(true, TDir);
 801       sys::path::append(TDir, Twine(ModelStorage));
 802       ModelStorage.swap(TDir);
 803     }
 804   }
 805
 806   ResultPath = ModelStorage;
 807   ResultPath.push_back(0);
 808   ResultPath.pop_back();
 809
 810   // Replace '%' with random chars.
 811   for (unsigned i = 0, e = ModelStorage.size(); i != e; ++i) {
 812     if (ModelStorage[i] == '%')
 813       ResultPath[i] = "0123456789abcdef"[sys::Process::GetRandomNumber() & 15];
 814   }
 815 }
 816
 817 std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
 818                                  SmallVectorImpl<char> &ResultPath,
 819                                  OpenFlags Flags, unsigned Mode) {
 820   return createUniqueEntity(Model, ResultFd, ResultPath, false, FS_File, Flags,
 821                             Mode);
 822 }
 823
 824 std::error_code createUniqueFile(const Twine &Model,
 825                                  SmallVectorImpl<char> &ResultPath,
 826                                  unsigned Mode) {
 827   int FD;
 828   auto EC = createUniqueFile(Model, FD, ResultPath, OF_None, Mode);
 829   if (EC)
 830     return EC;
 831   // FD is only needed to avoid race conditions. Close it right away.
 832   close(FD);
 833   return EC;
 834 }
 835
 836 static std::error_code
 837 createTemporaryFile(const Twine &Model, int &ResultFD,
 838                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type,
 839                     sys::fs::OpenFlags Flags = sys::fs::OF_None) {
 840   SmallString<128> Storage;
 841   StringRef P = Model.toNullTerminatedStringRef(Storage);
 842   assert(P.find_first_of(separators(Style::native)) == StringRef::npos &&
 843          "Model must be a simple filename.");
 844   // Use P.begin() so that createUniqueEntity doesn't need to recreate Storage.
 845   return createUniqueEntity(P.begin(), ResultFD, ResultPath, true, Type, Flags,
 846                             owner_read | owner_write);
 847 }
 848
 849 static std::error_code
 850 createTemporaryFile(const Twine &Prefix, StringRef Suffix, int &ResultFD,
 851                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type,
 852                     sys::fs::OpenFlags Flags = sys::fs::OF_None) {
 853   const char *Middle = Suffix.empty() ? "-%%%%%%" : "-%%%%%%.";
 854   return createTemporaryFile(Prefix + Middle + Suffix, ResultFD, ResultPath,
 855                              Type, Flags);
 856 }
 857
 858 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 859                                     int &ResultFD,
 860                                     SmallVectorImpl<char> &ResultPath,
 861                                     sys::fs::OpenFlags Flags) {
 862   return createTemporaryFile(Prefix, Suffix, ResultFD, ResultPath, FS_File,
 863                              Flags);
 864 }
 865
 866 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 867                                     SmallVectorImpl<char> &ResultPath,
 868                                     sys::fs::OpenFlags Flags) {
 869   int FD;
 870   auto EC = createTemporaryFile(Prefix, Suffix, FD, ResultPath, Flags);
 871   if (EC)
 872     return EC;
 873   // FD is only needed to avoid race conditions. Close it right away.
 874   close(FD);
 875   return EC;
 876 }
 877
 878 // This is a mkdtemp with a different pattern. We use createUniqueEntity mostly
 879 // for consistency. We should try using mkdtemp.
 880 std::error_code createUniqueDirectory(const Twine &Prefix,
 881                                       SmallVectorImpl<char> &ResultPath) {
 882   int Dummy;
 883   return createUniqueEntity(Prefix + "-%%%%%%", Dummy, ResultPath, true,
 884                             FS_Dir);
 885 }
 886
 887 std::error_code
 888 getPotentiallyUniqueFileName(const Twine &Model,
 889                              SmallVectorImpl<char> &ResultPath) {
 890   int Dummy;
 891   return createUniqueEntity(Model, Dummy, ResultPath, false, FS_Name);
 892 }
 893
 894 std::error_code
 895 getPotentiallyUniqueTempFileName(const Twine &Prefix, StringRef Suffix,
 896                                  SmallVectorImpl<char> &ResultPath) {
 897   int Dummy;
 898   return createTemporaryFile(Prefix, Suffix, Dummy, ResultPath, FS_Name);
 899 }
 900
 901 void make_absolute(const Twine &current_directory,
 902                    SmallVectorImpl<char> &path) {
 903   StringRef p(path.data(), path.size());
 904
 905   bool rootDirectory = path::has_root_directory(p);
 906   bool rootName = path::has_root_name(p);
 907
 908   // Already absolute.
 909   if ((rootName || real_style(Style::native) != Style::windows) &&
 910       rootDirectory)
 911     return;
 912
 913   // All of the following conditions will need the current directory.
 914   SmallString<128> current_dir;
 915   current_directory.toVector(current_dir);
 916
 917   // Relative path. Prepend the current directory.
 918   if (!rootName && !rootDirectory) {
 919     // Append path to the current directory.
 920     path::append(current_dir, p);
 921     // Set path to the result.
 922     path.swap(current_dir);
 923     return;
 924   }
 925
 926   if (!rootName && rootDirectory) {
 927     StringRef cdrn = path::root_name(current_dir);
 928     SmallString<128> curDirRootName(cdrn.begin(), cdrn.end());
 929     path::append(curDirRootName, p);
 930     // Set path to the result.
 931     path.swap(curDirRootName);
 932     return;
 933   }
 934
 935   if (rootName && !rootDirectory) {
 936     StringRef pRootName      = path::root_name(p);
 937     StringRef bRootDirectory = path::root_directory(current_dir);
 938     StringRef bRelativePath  = path::relative_path(current_dir);
 939     StringRef pRelativePath  = path::relative_path(p);
 940
 941     SmallString<128> res;
 942     path::append(res, pRootName, bRootDirectory, bRelativePath, pRelativePath);
 943     path.swap(res);
 944     return;
 945   }
 946
 947   llvm_unreachable("All rootName and rootDirectory combinations should have "
 948                    "occurred above!");
 949 }
 950
 951 std::error_code make_absolute(SmallVectorImpl<char> &path) {
 952   if (path::is_absolute(path))
 953     return {};
 954
 955   SmallString<128> current_dir;
 956   if (std::error_code ec = current_path(current_dir))
 957     return ec;
 958
 959   make_absolute(current_dir, path);
 960   return {};
 961 }
 962
 963 std::error_code create_directories(const Twine &Path, bool IgnoreExisting,
 964                                    perms Perms) {
 965   SmallString<128> PathStorage;
 966   StringRef P = Path.toStringRef(PathStorage);
 967
 968   // Be optimistic and try to create the directory
 969   std::error_code EC = create_directory(P, IgnoreExisting, Perms);
 970   // If we succeeded, or had any error other than the parent not existing, just
 971   // return it.
 972   if (EC != errc::no_such_file_or_directory)
 973     return EC;
 974
 975   // We failed because of a no_such_file_or_directory, try to create the
 976   // parent.
 977   StringRef Parent = path::parent_path(P);
 978   if (Parent.empty())
 979     return EC;
 980
 981   if ((EC = create_directories(Parent, IgnoreExisting, Perms)))
 982       return EC;
 983
 984   return create_directory(P, IgnoreExisting, Perms);
 985 }
 986
 987 static std::error_code copy_file_internal(int ReadFD, int WriteFD) {
 988   const size_t BufSize = 4096;
 989   char *Buf = new char[BufSize];
 990   int BytesRead = 0, BytesWritten = 0;
 991   for (;;) {
 992     BytesRead = read(ReadFD, Buf, BufSize);
 993     if (BytesRead <= 0)
 994       break;
 995     while (BytesRead) {
 996       BytesWritten = write(WriteFD, Buf, BytesRead);
 997       if (BytesWritten < 0)
 998         break;
 999       BytesRead -= BytesWritten;
1000     }
1001     if (BytesWritten < 0)
1002       break;
1003   }
1004   delete[] Buf;
1005
1006   if (BytesRead < 0 || BytesWritten < 0)
1007     return std::error_code(errno, std::generic_category());
1008   return std::error_code();
1009 }
1010
1011 #ifndef __APPLE__
1012 std::error_code copy_file(const Twine &From, const Twine &To) {
1013   int ReadFD, WriteFD;
1014   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1015     return EC;
1016   if (std::error_code EC =
1017           openFileForWrite(To, WriteFD, CD_CreateAlways, OF_None)) {
1018     close(ReadFD);
1019     return EC;
1020   }
1021
1022   std::error_code EC = copy_file_internal(ReadFD, WriteFD);
1023
1024   close(ReadFD);
1025   close(WriteFD);
1026
1027   return EC;
1028 }
1029 #endif
1030
1031 std::error_code copy_file(const Twine &From, int ToFD) {
1032   int ReadFD;
1033   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1034     return EC;
1035
1036   std::error_code EC = copy_file_internal(ReadFD, ToFD);
1037
1038   close(ReadFD);
1039
1040   return EC;
1041 }
1042
1043 ErrorOr<MD5::MD5Result> md5_contents(int FD) {
1044   MD5 Hash;
1045
1046   constexpr size_t BufSize = 4096;
1047   std::vector<uint8_t> Buf(BufSize);
1048   int BytesRead = 0;
1049   for (;;) {
1050     BytesRead = read(FD, Buf.data(), BufSize);
1051     if (BytesRead <= 0)
1052       break;
1053     Hash.update(makeArrayRef(Buf.data(), BytesRead));
1054   }
1055
1056   if (BytesRead < 0)
1057     return std::error_code(errno, std::generic_category());
1058   MD5::MD5Result Result;
1059   Hash.final(Result);
1060   return Result;
1061 }
1062
1063 ErrorOr<MD5::MD5Result> md5_contents(const Twine &Path) {
1064   int FD;
1065   if (auto EC = openFileForRead(Path, FD, OF_None))
1066     return EC;
1067
1068   auto Result = md5_contents(FD);
1069   close(FD);
1070   return Result;
1071 }
1072
1073 bool exists(const basic_file_status &status) {
1074   return status_known(status) && status.type() != file_type::file_not_found;
1075 }
1076
1077 bool status_known(const basic_file_status &s) {
1078   return s.type() != file_type::status_error;
1079 }
1080
1081 file_type get_file_type(const Twine &Path, bool Follow) {
1082   file_status st;
1083   if (status(Path, st, Follow))
1084     return file_type::status_error;
1085   return st.type();
1086 }
1087
1088 bool is_directory(const basic_file_status &status) {
1089   return status.type() == file_type::directory_file;
1090 }
1091
1092 std::error_code is_directory(const Twine &path, bool &result) {
1093   file_status st;
1094   if (std::error_code ec = status(path, st))
1095     return ec;
1096   result = is_directory(st);
1097   return std::error_code();
1098 }
1099
1100 bool is_regular_file(const basic_file_status &status) {
1101   return status.type() == file_type::regular_file;
1102 }
1103
1104 std::error_code is_regular_file(const Twine &path, bool &result) {
1105   file_status st;
1106   if (std::error_code ec = status(path, st))
1107     return ec;
1108   result = is_regular_file(st);
1109   return std::error_code();
1110 }
1111
1112 bool is_symlink_file(const basic_file_status &status) {
1113   return status.type() == file_type::symlink_file;
1114 }
1115
1116 std::error_code is_symlink_file(const Twine &path, bool &result) {
1117   file_status st;
1118   if (std::error_code ec = status(path, st, false))
1119     return ec;
1120   result = is_symlink_file(st);
1121   return std::error_code();
1122 }
1123
1124 bool is_other(const basic_file_status &status) {
1125   return exists(status) &&
1126          !is_regular_file(status) &&
1127          !is_directory(status);
1128 }
1129
1130 std::error_code is_other(const Twine &Path, bool &Result) {
1131   file_status FileStatus;
1132   if (std::error_code EC = status(Path, FileStatus))
1133     return EC;
1134   Result = is_other(FileStatus);
1135   return std::error_code();
1136 }
1137
1138 void directory_entry::replace_filename(const Twine &Filename, file_type Type,
1139                                        basic_file_status Status) {
1140   SmallString<128> PathStr = path::parent_path(Path);
1141   path::append(PathStr, Filename);
1142   this->Path = std::string(PathStr.str());
1143   this->Type = Type;
1144   this->Status = Status;
1145 }
1146
1147 ErrorOr<perms> getPermissions(const Twine &Path) {
1148   file_status Status;
1149   if (std::error_code EC = status(Path, Status))
1150     return EC;
1151
1152   return Status.permissions();
1153 }
1154
1155 size_t mapped_file_region::size() const {
1156   assert(Mapping && "Mapping failed but used anyway!");
1157   return Size;
1158 }
1159
1160 char *mapped_file_region::data() const {
1161   assert(Mapping && "Mapping failed but used anyway!");
1162   return reinterpret_cast<char *>(Mapping);
1163 }
1164
1165 const char *mapped_file_region::const_data() const {
1166   assert(Mapping && "Mapping failed but used anyway!");
1167   return reinterpret_cast<const char *>(Mapping);
1168 }
1169
1170 } // end namespace fs
1171 } // end namespace sys
1172 } // end namespace llvm
1173
1174 // Include the truly platform-specific parts.
1175 #if defined(LLVM_ON_UNIX)
1176 #include "Unix/Path.inc"
1177 #endif
1178 #if defined(_WIN32)
1179 #include "Windows/Path.inc"
1180 #endif
1181
1182 namespace llvm {
1183 namespace sys {
1184 namespace fs {
1185 TempFile::TempFile(StringRef Name, int FD)
1186     : TmpName(std::string(Name)), FD(FD) {}
1187 TempFile::TempFile(TempFile &&Other) { *this = std::move(Other); }
1188 TempFile &TempFile::operator=(TempFile &&Other) {
1189   TmpName = std::move(Other.TmpName);
1190   FD = Other.FD;
1191   Other.Done = true;
1192   Other.FD = -1;
1193   return *this;
1194 }
1195
1196 TempFile::~TempFile() { assert(Done); }
1197
1198 Error TempFile::discard() {
1199   Done = true;
1200   if (FD != -1 && close(FD) == -1) {
1201     std::error_code EC = std::error_code(errno, std::generic_category());
1202     return errorCodeToError(EC);
1203   }
1204   FD = -1;
1205
1206 #ifdef _WIN32
1207   // On windows closing will remove the file.
1208   TmpName = "";
1209   return Error::success();
1210 #else
1211   // Always try to close and remove.
1212   std::error_code RemoveEC;
1213   if (!TmpName.empty()) {
1214     RemoveEC = fs::remove(TmpName);
1215     sys::DontRemoveFileOnSignal(TmpName);
1216     if (!RemoveEC)
1217       TmpName = "";
1218   }
1219   return errorCodeToError(RemoveEC);
1220 #endif
1221 }
1222
1223 Error TempFile::keep(const Twine &Name) {
1224   assert(!Done);
1225   Done = true;
1226   // Always try to close and rename.
1227 #ifdef _WIN32
1228   // If we can't cancel the delete don't rename.
1229   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1230   std::error_code RenameEC = setDeleteDisposition(H, false);
1231   if (!RenameEC) {
1232     RenameEC = rename_handle(H, Name);
1233     // If rename failed because it's cross-device, copy instead
1234     if (RenameEC ==
1235       std::error_code(ERROR_NOT_SAME_DEVICE, std::system_category())) {
1236       RenameEC = copy_file(TmpName, Name);
1237       setDeleteDisposition(H, true);
1238     }
1239   }
1240
1241   // If we can't rename, discard the temporary file.
1242   if (RenameEC)
1243     setDeleteDisposition(H, true);
1244 #else
1245   std::error_code RenameEC = fs::rename(TmpName, Name);
1246   if (RenameEC) {
1247     // If we can't rename, try to copy to work around cross-device link issues.
1248     RenameEC = sys::fs::copy_file(TmpName, Name);
1249     // If we can't rename or copy, discard the temporary file.
1250     if (RenameEC)
1251       remove(TmpName);
1252   }
1253   sys::DontRemoveFileOnSignal(TmpName);
1254 #endif
1255
1256   if (!RenameEC)
1257     TmpName = "";
1258
1259   if (close(FD) == -1) {
1260     std::error_code EC(errno, std::generic_category());
1261     return errorCodeToError(EC);
1262   }
1263   FD = -1;
1264
1265   return errorCodeToError(RenameEC);
1266 }
1267
1268 Error TempFile::keep() {
1269   assert(!Done);
1270   Done = true;
1271
1272 #ifdef _WIN32
1273   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1274   if (std::error_code EC = setDeleteDisposition(H, false))
1275     return errorCodeToError(EC);
1276 #else
1277   sys::DontRemoveFileOnSignal(TmpName);
1278 #endif
1279
1280   TmpName = "";
1281
1282   if (close(FD) == -1) {
1283     std::error_code EC(errno, std::generic_category());
1284     return errorCodeToError(EC);
1285   }
1286   FD = -1;
1287
1288   return Error::success();
1289 }
1290
1291 Expected<TempFile> TempFile::create(const Twine &Model, unsigned Mode,
1292                                     OpenFlags ExtraFlags) {
1293   int FD;
1294   SmallString<128> ResultPath;
1295   if (std::error_code EC =
1296           createUniqueFile(Model, FD, ResultPath, OF_Delete | ExtraFlags, Mode))
1297     return errorCodeToError(EC);
1298
1299   TempFile Ret(ResultPath, FD);
1300 #ifndef _WIN32
1301   if (sys::RemoveFileOnSignal(ResultPath)) {
1302     // Make sure we delete the file when RemoveFileOnSignal fails.
1303     consumeError(Ret.discard());
1304     std::error_code EC(errc::operation_not_permitted);
1305     return errorCodeToError(EC);
1306   }
1307 #endif
1308   return std::move(Ret);
1309 }
1310 } // namespace fs
1311
1312 } // namespace sys
1313 } // namespace llvm