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/ADT/ScopeExit.h"
  16 #include "llvm/ADT/StringExtras.h"
  17 #include "llvm/Config/config.h"
  18 #include "llvm/Config/llvm-config.h"
  19 #include "llvm/Support/Errc.h"
  20 #include "llvm/Support/ErrorHandling.h"
  21 #include "llvm/Support/FileSystem.h"
  22 #include "llvm/Support/Process.h"
  23 #include "llvm/Support/Signals.h"
  24 #include <cctype>
  25
  26 #if !defined(_MSC_VER) && !defined(__MINGW32__)
  27 #include <unistd.h>
  28 #else
  29 #include <io.h>
  30 #endif
  31
  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     if (style != Style::native)
  42       return style;
  43     if (is_style_posix(style))
  44       return Style::posix;
  45     return LLVM_WINDOWS_PREFER_FORWARD_SLASH ? Style::windows_slash
  46                                              : Style::windows_backslash;
  47   }
  48
  49   inline const char *separators(Style style) {
  50     if (is_style_windows(style))
  51       return "\\/";
  52     return "/";
  53   }
  54
  55   inline char preferred_separator(Style style) {
  56     if (real_style(style) == Style::windows)
  57       return '\\';
  58     return '/';
  59   }
  60
  61   StringRef find_first_component(StringRef path, Style style) {
  62     // Look for this first component in the following order.
  63     // * empty (in this case we return an empty string)
  64     // * either C: or {//,\\}net.
  65     // * {/,\}
  66     // * {file,directory}name
  67
  68     if (path.empty())
  69       return path;
  70
  71     if (is_style_windows(style)) {
  72       // C:
  73       if (path.size() >= 2 &&
  74           std::isalpha(static_cast<unsigned char>(path[0])) && path[1] == ':')
  75         return path.substr(0, 2);
  76     }
  77
  78     // //net
  79     if ((path.size() > 2) && is_separator(path[0], style) &&
  80         path[0] == path[1] && !is_separator(path[2], style)) {
  81       // Find the next directory separator.
  82       size_t end = path.find_first_of(separators(style), 2);
  83       return path.substr(0, end);
  84     }
  85
  86     // {/,\}
  87     if (is_separator(path[0], style))
  88       return path.substr(0, 1);
  89
  90     // * {file,directory}name
  91     size_t end = path.find_first_of(separators(style));
  92     return path.substr(0, end);
  93   }
  94
  95   // Returns the first character of the filename in str. For paths ending in
  96   // '/', it returns the position of the '/'.
  97   size_t filename_pos(StringRef str, Style style) {
  98     if (str.size() > 0 && is_separator(str[str.size() - 1], style))
  99       return str.size() - 1;
 100
 101     size_t pos = str.find_last_of(separators(style), str.size() - 1);
 102
 103     if (is_style_windows(style)) {
 104       if (pos == StringRef::npos)
 105         pos = str.find_last_of(':', str.size() - 1);
 106     }
 107
 108     if (pos == StringRef::npos || (pos == 1 && is_separator(str[0], style)))
 109       return 0;
 110
 111     return pos + 1;
 112   }
 113
 114   // Returns the position of the root directory in str. If there is no root
 115   // directory in str, it returns StringRef::npos.
 116   size_t root_dir_start(StringRef str, Style style) {
 117     // case "c:/"
 118     if (is_style_windows(style)) {
 119       if (str.size() > 2 && str[1] == ':' && is_separator(str[2], style))
 120         return 2;
 121     }
 122
 123     // case "//net"
 124     if (str.size() > 3 && is_separator(str[0], style) && str[0] == str[1] &&
 125         !is_separator(str[2], style)) {
 126       return str.find_first_of(separators(style), 2);
 127     }
 128
 129     // case "/"
 130     if (str.size() > 0 && is_separator(str[0], style))
 131       return 0;
 132
 133     return StringRef::npos;
 134   }
 135
 136   // Returns the position past the end of the "parent path" of path. The parent
 137   // path will not end in '/', unless the parent is the root directory. If the
 138   // path has no parent, 0 is returned.
 139   size_t parent_path_end(StringRef path, Style style) {
 140     size_t end_pos = filename_pos(path, style);
 141
 142     bool filename_was_sep =
 143         path.size() > 0 && is_separator(path[end_pos], style);
 144
 145     // Skip separators until we reach root dir (or the start of the string).
 146     size_t root_dir_pos = root_dir_start(path, style);
 147     while (end_pos > 0 &&
 148            (root_dir_pos == StringRef::npos || end_pos > root_dir_pos) &&
 149            is_separator(path[end_pos - 1], style))
 150       --end_pos;
 151
 152     if (end_pos == root_dir_pos && !filename_was_sep) {
 153       // We've reached the root dir and the input path was *not* ending in a
 154       // sequence of slashes. Include the root dir in the parent path.
 155       return root_dir_pos + 1;
 156     }
 157
 158     // Otherwise, just include before the last slash.
 159     return end_pos;
 160   }
 161 } // end unnamed namespace
 162
 163 enum FSEntity {
 164   FS_Dir,
 165   FS_File,
 166   FS_Name
 167 };
 168
 169 static std::error_code
 170 createUniqueEntity(const Twine &Model, int &ResultFD,
 171                    SmallVectorImpl<char> &ResultPath, bool MakeAbsolute,
 172                    FSEntity Type, sys::fs::OpenFlags Flags = sys::fs::OF_None,
 173                    unsigned Mode = 0) {
 174
 175   // Limit the number of attempts we make, so that we don't infinite loop. E.g.
 176   // "permission denied" could be for a specific file (so we retry with a
 177   // different name) or for the whole directory (retry would always fail).
 178   // Checking which is racy, so we try a number of times, then give up.
 179   std::error_code EC;
 180   for (int Retries = 128; Retries > 0; --Retries) {
 181     sys::fs::createUniquePath(Model, ResultPath, MakeAbsolute);
 182     // Try to open + create the file.
 183     switch (Type) {
 184     case FS_File: {
 185       EC = sys::fs::openFileForReadWrite(Twine(ResultPath.begin()), ResultFD,
 186                                          sys::fs::CD_CreateNew, Flags, Mode);
 187       if (EC) {
 188         // errc::permission_denied happens on Windows when we try to open a file
 189         // that has been marked for deletion.
 190         if (EC == errc::file_exists || EC == errc::permission_denied)
 191           continue;
 192         return EC;
 193       }
 194
 195       return std::error_code();
 196     }
 197
 198     case FS_Name: {
 199       EC = sys::fs::access(ResultPath.begin(), sys::fs::AccessMode::Exist);
 200       if (EC == errc::no_such_file_or_directory)
 201         return std::error_code();
 202       if (EC)
 203         return EC;
 204       continue;
 205     }
 206
 207     case FS_Dir: {
 208       EC = sys::fs::create_directory(ResultPath.begin(), false);
 209       if (EC) {
 210         if (EC == errc::file_exists)
 211           continue;
 212         return EC;
 213       }
 214       return std::error_code();
 215     }
 216     }
 217     llvm_unreachable("Invalid Type");
 218   }
 219   return EC;
 220 }
 221
 222 namespace llvm {
 223 namespace sys  {
 224 namespace path {
 225
 226 const_iterator begin(StringRef path, Style style) {
 227   const_iterator i;
 228   i.Path      = path;
 229   i.Component = find_first_component(path, style);
 230   i.Position  = 0;
 231   i.S = style;
 232   return i;
 233 }
 234
 235 const_iterator end(StringRef path) {
 236   const_iterator i;
 237   i.Path      = path;
 238   i.Position  = path.size();
 239   return i;
 240 }
 241
 242 const_iterator &const_iterator::operator++() {
 243   assert(Position < Path.size() && "Tried to increment past end!");
 244
 245   // Increment Position to past the current component
 246   Position += Component.size();
 247
 248   // Check for end.
 249   if (Position == Path.size()) {
 250     Component = StringRef();
 251     return *this;
 252   }
 253
 254   // Both POSIX and Windows treat paths that begin with exactly two separators
 255   // specially.
 256   bool was_net = Component.size() > 2 && is_separator(Component[0], S) &&
 257                  Component[1] == Component[0] && !is_separator(Component[2], S);
 258
 259   // Handle separators.
 260   if (is_separator(Path[Position], S)) {
 261     // Root dir.
 262     if (was_net ||
 263         // c:/
 264         (is_style_windows(S) && Component.ends_with(":"))) {
 265       Component = Path.substr(Position, 1);
 266       return *this;
 267     }
 268
 269     // Skip extra separators.
 270     while (Position != Path.size() && is_separator(Path[Position], S)) {
 271       ++Position;
 272     }
 273
 274     // Treat trailing '/' as a '.', unless it is the root dir.
 275     if (Position == Path.size() && Component != "/") {
 276       --Position;
 277       Component = ".";
 278       return *this;
 279     }
 280   }
 281
 282   // Find next component.
 283   size_t end_pos = Path.find_first_of(separators(S), Position);
 284   Component = Path.slice(Position, end_pos);
 285
 286   return *this;
 287 }
 288
 289 bool const_iterator::operator==(const const_iterator &RHS) const {
 290   return Path.begin() == RHS.Path.begin() && Position == RHS.Position;
 291 }
 292
 293 ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
 294   return Position - RHS.Position;
 295 }
 296
 297 reverse_iterator rbegin(StringRef Path, Style style) {
 298   reverse_iterator I;
 299   I.Path = Path;
 300   I.Position = Path.size();
 301   I.S = style;
 302   ++I;
 303   return I;
 304 }
 305
 306 reverse_iterator rend(StringRef Path) {
 307   reverse_iterator I;
 308   I.Path = Path;
 309   I.Component = Path.substr(0, 0);
 310   I.Position = 0;
 311   return I;
 312 }
 313
 314 reverse_iterator &reverse_iterator::operator++() {
 315   size_t root_dir_pos = root_dir_start(Path, S);
 316
 317   // Skip separators unless it's the root directory.
 318   size_t end_pos = Position;
 319   while (end_pos > 0 && (end_pos - 1) != root_dir_pos &&
 320          is_separator(Path[end_pos - 1], S))
 321     --end_pos;
 322
 323   // Treat trailing '/' as a '.', unless it is the root dir.
 324   if (Position == Path.size() && !Path.empty() &&
 325       is_separator(Path.back(), S) &&
 326       (root_dir_pos == StringRef::npos || end_pos - 1 > root_dir_pos)) {
 327     --Position;
 328     Component = ".";
 329     return *this;
 330   }
 331
 332   // Find next separator.
 333   size_t start_pos = filename_pos(Path.substr(0, end_pos), S);
 334   Component = Path.slice(start_pos, end_pos);
 335   Position = start_pos;
 336   return *this;
 337 }
 338
 339 bool reverse_iterator::operator==(const reverse_iterator &RHS) const {
 340   return Path.begin() == RHS.Path.begin() && Component == RHS.Component &&
 341          Position == RHS.Position;
 342 }
 343
 344 ptrdiff_t reverse_iterator::operator-(const reverse_iterator &RHS) const {
 345   return Position - RHS.Position;
 346 }
 347
 348 StringRef root_path(StringRef path, Style style) {
 349   const_iterator b = begin(path, style), pos = b, e = end(path);
 350   if (b != e) {
 351     bool has_net =
 352         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 353     bool has_drive = is_style_windows(style) && b->ends_with(":");
 354
 355     if (has_net || has_drive) {
 356       if ((++pos != e) && is_separator((*pos)[0], style)) {
 357         // {C:/,//net/}, so get the first two components.
 358         return path.substr(0, b->size() + pos->size());
 359       }
 360       // just {C:,//net}, return the first component.
 361       return *b;
 362     }
 363
 364     // POSIX style root directory.
 365     if (is_separator((*b)[0], style)) {
 366       return *b;
 367     }
 368   }
 369
 370   return StringRef();
 371 }
 372
 373 StringRef root_name(StringRef path, Style style) {
 374   const_iterator b = begin(path, style), e = end(path);
 375   if (b != e) {
 376     bool has_net =
 377         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 378     bool has_drive = is_style_windows(style) && b->ends_with(":");
 379
 380     if (has_net || has_drive) {
 381       // just {C:,//net}, return the first component.
 382       return *b;
 383     }
 384   }
 385
 386   // No path or no name.
 387   return StringRef();
 388 }
 389
 390 StringRef root_directory(StringRef path, Style style) {
 391   const_iterator b = begin(path, style), pos = b, e = end(path);
 392   if (b != e) {
 393     bool has_net =
 394         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 395     bool has_drive = is_style_windows(style) && b->ends_with(":");
 396
 397     if ((has_net || has_drive) &&
 398         // {C:,//net}, skip to the next component.
 399         (++pos != e) && is_separator((*pos)[0], style)) {
 400       return *pos;
 401     }
 402
 403     // POSIX style root directory.
 404     if (!has_net && is_separator((*b)[0], style)) {
 405       return *b;
 406     }
 407   }
 408
 409   // No path or no root.
 410   return StringRef();
 411 }
 412
 413 StringRef relative_path(StringRef path, Style style) {
 414   StringRef root = root_path(path, style);
 415   return path.substr(root.size());
 416 }
 417
 418 void append(SmallVectorImpl<char> &path, Style style, const Twine &a,
 419             const Twine &b, const Twine &c, const Twine &d) {
 420   SmallString<32> a_storage;
 421   SmallString<32> b_storage;
 422   SmallString<32> c_storage;
 423   SmallString<32> d_storage;
 424
 425   SmallVector<StringRef, 4> components;
 426   if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
 427   if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
 428   if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
 429   if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
 430
 431   for (auto &component : components) {
 432     bool path_has_sep =
 433         !path.empty() && is_separator(path[path.size() - 1], style);
 434     if (path_has_sep) {
 435       // Strip separators from beginning of component.
 436       size_t loc = component.find_first_not_of(separators(style));
 437       StringRef c = component.substr(loc);
 438
 439       // Append it.
 440       path.append(c.begin(), c.end());
 441       continue;
 442     }
 443
 444     bool component_has_sep =
 445         !component.empty() && is_separator(component[0], style);
 446     if (!component_has_sep &&
 447         !(path.empty() || has_root_name(component, style))) {
 448       // Add a separator.
 449       path.push_back(preferred_separator(style));
 450     }
 451
 452     path.append(component.begin(), component.end());
 453   }
 454 }
 455
 456 void append(SmallVectorImpl<char> &path, const Twine &a, const Twine &b,
 457             const Twine &c, const Twine &d) {
 458   append(path, Style::native, a, b, c, d);
 459 }
 460
 461 void append(SmallVectorImpl<char> &path, const_iterator begin,
 462             const_iterator end, Style style) {
 463   for (; begin != end; ++begin)
 464     path::append(path, style, *begin);
 465 }
 466
 467 StringRef parent_path(StringRef path, Style style) {
 468   size_t end_pos = parent_path_end(path, style);
 469   if (end_pos == StringRef::npos)
 470     return StringRef();
 471   return path.substr(0, end_pos);
 472 }
 473
 474 void remove_filename(SmallVectorImpl<char> &path, Style style) {
 475   size_t end_pos = parent_path_end(StringRef(path.begin(), path.size()), style);
 476   if (end_pos != StringRef::npos)
 477     path.truncate(end_pos);
 478 }
 479
 480 void replace_extension(SmallVectorImpl<char> &path, const Twine &extension,
 481                        Style style) {
 482   StringRef p(path.begin(), path.size());
 483   SmallString<32> ext_storage;
 484   StringRef ext = extension.toStringRef(ext_storage);
 485
 486   // Erase existing extension.
 487   size_t pos = p.find_last_of('.');
 488   if (pos != StringRef::npos && pos >= filename_pos(p, style))
 489     path.truncate(pos);
 490
 491   // Append '.' if needed.
 492   if (ext.size() > 0 && ext[0] != '.')
 493     path.push_back('.');
 494
 495   // Append extension.
 496   path.append(ext.begin(), ext.end());
 497 }
 498
 499 static bool starts_with(StringRef Path, StringRef Prefix,
 500                         Style style = Style::native) {
 501   // Windows prefix matching : case and separator insensitive
 502   if (is_style_windows(style)) {
 503     if (Path.size() < Prefix.size())
 504       return false;
 505     for (size_t I = 0, E = Prefix.size(); I != E; ++I) {
 506       bool SepPath = is_separator(Path[I], style);
 507       bool SepPrefix = is_separator(Prefix[I], style);
 508       if (SepPath != SepPrefix)
 509         return false;
 510       if (!SepPath && toLower(Path[I]) != toLower(Prefix[I]))
 511         return false;
 512     }
 513     return true;
 514   }
 515   return Path.starts_with(Prefix);
 516 }
 517
 518 bool replace_path_prefix(SmallVectorImpl<char> &Path, StringRef OldPrefix,
 519                          StringRef NewPrefix, Style style) {
 520   if (OldPrefix.empty() && NewPrefix.empty())
 521     return false;
 522
 523   StringRef OrigPath(Path.begin(), Path.size());
 524   if (!starts_with(OrigPath, OldPrefix, style))
 525     return false;
 526
 527   // If prefixes have the same size we can simply copy the new one over.
 528   if (OldPrefix.size() == NewPrefix.size()) {
 529     llvm::copy(NewPrefix, Path.begin());
 530     return true;
 531   }
 532
 533   StringRef RelPath = OrigPath.substr(OldPrefix.size());
 534   SmallString<256> NewPath;
 535   (Twine(NewPrefix) + RelPath).toVector(NewPath);
 536   Path.swap(NewPath);
 537   return true;
 538 }
 539
 540 void native(const Twine &path, SmallVectorImpl<char> &result, Style style) {
 541   assert((!path.isSingleStringRef() ||
 542           path.getSingleStringRef().data() != result.data()) &&
 543          "path and result are not allowed to overlap!");
 544   // Clear result.
 545   result.clear();
 546   path.toVector(result);
 547   native(result, style);
 548 }
 549
 550 void native(SmallVectorImpl<char> &Path, Style style) {
 551   if (Path.empty())
 552     return;
 553   if (is_style_windows(style)) {
 554     for (char &Ch : Path)
 555       if (is_separator(Ch, style))
 556         Ch = preferred_separator(style);
 557     if (Path[0] == '~' && (Path.size() == 1 || is_separator(Path[1], style))) {
 558       SmallString<128> PathHome;
 559       home_directory(PathHome);
 560       PathHome.append(Path.begin() + 1, Path.end());
 561       Path = PathHome;
 562     }
 563   } else {
 564     std::replace(Path.begin(), Path.end(), '\\', '/');
 565   }
 566 }
 567
 568 std::string convert_to_slash(StringRef path, Style style) {
 569   if (is_style_posix(style))
 570     return std::string(path);
 571
 572   std::string s = path.str();
 573   std::replace(s.begin(), s.end(), '\\', '/');
 574   return s;
 575 }
 576
 577 StringRef filename(StringRef path, Style style) { return *rbegin(path, style); }
 578
 579 StringRef stem(StringRef path, Style style) {
 580   StringRef fname = filename(path, style);
 581   size_t pos = fname.find_last_of('.');
 582   if (pos == StringRef::npos)
 583     return fname;
 584   if ((fname.size() == 1 && fname == ".") ||
 585       (fname.size() == 2 && fname == ".."))
 586     return fname;
 587   return fname.substr(0, pos);
 588 }
 589
 590 StringRef extension(StringRef path, Style style) {
 591   StringRef fname = filename(path, style);
 592   size_t pos = fname.find_last_of('.');
 593   if (pos == StringRef::npos)
 594     return StringRef();
 595   if ((fname.size() == 1 && fname == ".") ||
 596       (fname.size() == 2 && fname == ".."))
 597     return StringRef();
 598   return fname.substr(pos);
 599 }
 600
 601 bool is_separator(char value, Style style) {
 602   if (value == '/')
 603     return true;
 604   if (is_style_windows(style))
 605     return value == '\\';
 606   return false;
 607 }
 608
 609 StringRef get_separator(Style style) {
 610   if (real_style(style) == Style::windows)
 611     return "\\";
 612   return "/";
 613 }
 614
 615 bool has_root_name(const Twine &path, Style style) {
 616   SmallString<128> path_storage;
 617   StringRef p = path.toStringRef(path_storage);
 618
 619   return !root_name(p, style).empty();
 620 }
 621
 622 bool has_root_directory(const Twine &path, Style style) {
 623   SmallString<128> path_storage;
 624   StringRef p = path.toStringRef(path_storage);
 625
 626   return !root_directory(p, style).empty();
 627 }
 628
 629 bool has_root_path(const Twine &path, Style style) {
 630   SmallString<128> path_storage;
 631   StringRef p = path.toStringRef(path_storage);
 632
 633   return !root_path(p, style).empty();
 634 }
 635
 636 bool has_relative_path(const Twine &path, Style style) {
 637   SmallString<128> path_storage;
 638   StringRef p = path.toStringRef(path_storage);
 639
 640   return !relative_path(p, style).empty();
 641 }
 642
 643 bool has_filename(const Twine &path, Style style) {
 644   SmallString<128> path_storage;
 645   StringRef p = path.toStringRef(path_storage);
 646
 647   return !filename(p, style).empty();
 648 }
 649
 650 bool has_parent_path(const Twine &path, Style style) {
 651   SmallString<128> path_storage;
 652   StringRef p = path.toStringRef(path_storage);
 653
 654   return !parent_path(p, style).empty();
 655 }
 656
 657 bool has_stem(const Twine &path, Style style) {
 658   SmallString<128> path_storage;
 659   StringRef p = path.toStringRef(path_storage);
 660
 661   return !stem(p, style).empty();
 662 }
 663
 664 bool has_extension(const Twine &path, Style style) {
 665   SmallString<128> path_storage;
 666   StringRef p = path.toStringRef(path_storage);
 667
 668   return !extension(p, style).empty();
 669 }
 670
 671 bool is_absolute(const Twine &path, Style style) {
 672   SmallString<128> path_storage;
 673   StringRef p = path.toStringRef(path_storage);
 674
 675   bool rootDir = has_root_directory(p, style);
 676   bool rootName = is_style_posix(style) || has_root_name(p, style);
 677
 678   return rootDir && rootName;
 679 }
 680
 681 bool is_absolute_gnu(const Twine &path, Style style) {
 682   SmallString<128> path_storage;
 683   StringRef p = path.toStringRef(path_storage);
 684
 685   // Handle '/' which is absolute for both Windows and POSIX systems.
 686   // Handle '\\' on Windows.
 687   if (!p.empty() && is_separator(p.front(), style))
 688     return true;
 689
 690   if (is_style_windows(style)) {
 691     // Handle drive letter pattern (a character followed by ':') on Windows.
 692     if (p.size() >= 2 && (p[0] && p[1] == ':'))
 693       return true;
 694   }
 695
 696   return false;
 697 }
 698
 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 // Remove path traversal components ("." and "..") when possible, and
 714 // canonicalize slashes.
 715 bool remove_dots(SmallVectorImpl<char> &the_path, bool remove_dot_dot,
 716                  Style style) {
 717   style = real_style(style);
 718   StringRef remaining(the_path.data(), the_path.size());
 719   bool needs_change = false;
 720   SmallVector<StringRef, 16> components;
 721
 722   // Consume the root path, if present.
 723   StringRef root = path::root_path(remaining, style);
 724   bool absolute = !root.empty();
 725   if (absolute)
 726     remaining = remaining.drop_front(root.size());
 727
 728   // Loop over path components manually. This makes it easier to detect
 729   // non-preferred slashes and double separators that must be canonicalized.
 730   while (!remaining.empty()) {
 731     size_t next_slash = remaining.find_first_of(separators(style));
 732     if (next_slash == StringRef::npos)
 733       next_slash = remaining.size();
 734     StringRef component = remaining.take_front(next_slash);
 735     remaining = remaining.drop_front(next_slash);
 736
 737     // Eat the slash, and check if it is the preferred separator.
 738     if (!remaining.empty()) {
 739       needs_change |= remaining.front() != preferred_separator(style);
 740       remaining = remaining.drop_front();
 741       // The path needs to be rewritten if it has a trailing slash.
 742       // FIXME: This is emergent behavior that could be removed.
 743       needs_change |= remaining.empty();
 744     }
 745
 746     // Check for path traversal components or double separators.
 747     if (component.empty() || component == ".") {
 748       needs_change = true;
 749     } else if (remove_dot_dot && component == "..") {
 750       needs_change = true;
 751       // Do not allow ".." to remove the root component. If this is the
 752       // beginning of a relative path, keep the ".." component.
 753       if (!components.empty() && components.back() != "..") {
 754         components.pop_back();
 755       } else if (!absolute) {
 756         components.push_back(component);
 757       }
 758     } else {
 759       components.push_back(component);
 760     }
 761   }
 762
 763   SmallString<256> buffer = root;
 764   // "root" could be "/", which may need to be translated into "\".
 765   make_preferred(buffer, style);
 766   needs_change |= root != buffer;
 767
 768   // Avoid rewriting the path unless we have to.
 769   if (!needs_change)
 770     return false;
 771
 772   if (!components.empty()) {
 773     buffer += components[0];
 774     for (StringRef C : ArrayRef(components).drop_front()) {
 775       buffer += preferred_separator(style);
 776       buffer += C;
 777     }
 778   }
 779   the_path.swap(buffer);
 780   return true;
 781 }
 782
 783 } // end namespace path
 784
 785 namespace fs {
 786
 787 std::error_code getUniqueID(const Twine Path, UniqueID &Result) {
 788   file_status Status;
 789   std::error_code EC = status(Path, Status);
 790   if (EC)
 791     return EC;
 792   Result = Status.getUniqueID();
 793   return std::error_code();
 794 }
 795
 796 void createUniquePath(const Twine &Model, SmallVectorImpl<char> &ResultPath,
 797                       bool MakeAbsolute) {
 798   SmallString<128> ModelStorage;
 799   Model.toVector(ModelStorage);
 800
 801   if (MakeAbsolute) {
 802     // Make model absolute by prepending a temp directory if it's not already.
 803     if (!sys::path::is_absolute(Twine(ModelStorage))) {
 804       SmallString<128> TDir;
 805       sys::path::system_temp_directory(true, TDir);
 806       sys::path::append(TDir, Twine(ModelStorage));
 807       ModelStorage.swap(TDir);
 808     }
 809   }
 810
 811   ResultPath = ModelStorage;
 812   ResultPath.push_back(0);
 813   ResultPath.pop_back();
 814
 815   // Replace '%' with random chars.
 816   for (unsigned i = 0, e = ModelStorage.size(); i != e; ++i) {
 817     if (ModelStorage[i] == '%')
 818       ResultPath[i] = "0123456789abcdef"[sys::Process::GetRandomNumber() & 15];
 819   }
 820 }
 821
 822 std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
 823                                  SmallVectorImpl<char> &ResultPath,
 824                                  OpenFlags Flags, unsigned Mode) {
 825   return createUniqueEntity(Model, ResultFd, ResultPath, false, FS_File, Flags,
 826                             Mode);
 827 }
 828
 829 std::error_code createUniqueFile(const Twine &Model,
 830                                  SmallVectorImpl<char> &ResultPath,
 831                                  unsigned Mode) {
 832   int FD;
 833   auto EC = createUniqueFile(Model, FD, ResultPath, OF_None, Mode);
 834   if (EC)
 835     return EC;
 836   // FD is only needed to avoid race conditions. Close it right away.
 837   close(FD);
 838   return EC;
 839 }
 840
 841 static std::error_code
 842 createTemporaryFile(const Twine &Model, int &ResultFD,
 843                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type,
 844                     sys::fs::OpenFlags Flags = sys::fs::OF_None) {
 845   SmallString<128> Storage;
 846   StringRef P = Model.toNullTerminatedStringRef(Storage);
 847   assert(P.find_first_of(separators(Style::native)) == StringRef::npos &&
 848          "Model must be a simple filename.");
 849   // Use P.begin() so that createUniqueEntity doesn't need to recreate Storage.
 850   return createUniqueEntity(P.begin(), ResultFD, ResultPath, true, Type, Flags,
 851                             all_read | all_write);
 852 }
 853
 854 static std::error_code
 855 createTemporaryFile(const Twine &Prefix, StringRef Suffix, int &ResultFD,
 856                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type,
 857                     sys::fs::OpenFlags Flags = sys::fs::OF_None) {
 858   const char *Middle = Suffix.empty() ? "-%%%%%%" : "-%%%%%%.";
 859   return createTemporaryFile(Prefix + Middle + Suffix, ResultFD, ResultPath,
 860                              Type, Flags);
 861 }
 862
 863 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 864                                     int &ResultFD,
 865                                     SmallVectorImpl<char> &ResultPath,
 866                                     sys::fs::OpenFlags Flags) {
 867   return createTemporaryFile(Prefix, Suffix, ResultFD, ResultPath, FS_File,
 868                              Flags);
 869 }
 870
 871 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 872                                     SmallVectorImpl<char> &ResultPath,
 873                                     sys::fs::OpenFlags Flags) {
 874   int FD;
 875   auto EC = createTemporaryFile(Prefix, Suffix, FD, ResultPath, Flags);
 876   if (EC)
 877     return EC;
 878   // FD is only needed to avoid race conditions. Close it right away.
 879   close(FD);
 880   return EC;
 881 }
 882
 883 // This is a mkdtemp with a different pattern. We use createUniqueEntity mostly
 884 // for consistency. We should try using mkdtemp.
 885 std::error_code createUniqueDirectory(const Twine &Prefix,
 886                                       SmallVectorImpl<char> &ResultPath) {
 887   int Dummy;
 888   return createUniqueEntity(Prefix + "-%%%%%%", Dummy, ResultPath, true,
 889                             FS_Dir);
 890 }
 891
 892 std::error_code
 893 getPotentiallyUniqueFileName(const Twine &Model,
 894                              SmallVectorImpl<char> &ResultPath) {
 895   int Dummy;
 896   return createUniqueEntity(Model, Dummy, ResultPath, false, FS_Name);
 897 }
 898
 899 std::error_code
 900 getPotentiallyUniqueTempFileName(const Twine &Prefix, StringRef Suffix,
 901                                  SmallVectorImpl<char> &ResultPath) {
 902   int Dummy;
 903   return createTemporaryFile(Prefix, Suffix, Dummy, ResultPath, FS_Name);
 904 }
 905
 906 void make_absolute(const Twine &current_directory,
 907                    SmallVectorImpl<char> &path) {
 908   StringRef p(path.data(), path.size());
 909
 910   bool rootDirectory = path::has_root_directory(p);
 911   bool rootName = path::has_root_name(p);
 912
 913   // Already absolute.
 914   if ((rootName || is_style_posix(Style::native)) && rootDirectory)
 915     return;
 916
 917   // All of the following conditions will need the current directory.
 918   SmallString<128> current_dir;
 919   current_directory.toVector(current_dir);
 920
 921   // Relative path. Prepend the current directory.
 922   if (!rootName && !rootDirectory) {
 923     // Append path to the current directory.
 924     path::append(current_dir, p);
 925     // Set path to the result.
 926     path.swap(current_dir);
 927     return;
 928   }
 929
 930   if (!rootName && rootDirectory) {
 931     StringRef cdrn = path::root_name(current_dir);
 932     SmallString<128> curDirRootName(cdrn.begin(), cdrn.end());
 933     path::append(curDirRootName, p);
 934     // Set path to the result.
 935     path.swap(curDirRootName);
 936     return;
 937   }
 938
 939   if (rootName && !rootDirectory) {
 940     StringRef pRootName      = path::root_name(p);
 941     StringRef bRootDirectory = path::root_directory(current_dir);
 942     StringRef bRelativePath  = path::relative_path(current_dir);
 943     StringRef pRelativePath  = path::relative_path(p);
 944
 945     SmallString<128> res;
 946     path::append(res, pRootName, bRootDirectory, bRelativePath, pRelativePath);
 947     path.swap(res);
 948     return;
 949   }
 950
 951   llvm_unreachable("All rootName and rootDirectory combinations should have "
 952                    "occurred above!");
 953 }
 954
 955 std::error_code make_absolute(SmallVectorImpl<char> &path) {
 956   if (path::is_absolute(path))
 957     return {};
 958
 959   SmallString<128> current_dir;
 960   if (std::error_code ec = current_path(current_dir))
 961     return ec;
 962
 963   make_absolute(current_dir, path);
 964   return {};
 965 }
 966
 967 std::error_code create_directories(const Twine &Path, bool IgnoreExisting,
 968                                    perms Perms) {
 969   SmallString<128> PathStorage;
 970   StringRef P = Path.toStringRef(PathStorage);
 971
 972   // Be optimistic and try to create the directory
 973   std::error_code EC = create_directory(P, IgnoreExisting, Perms);
 974   // If we succeeded, or had any error other than the parent not existing, just
 975   // return it.
 976   if (EC != errc::no_such_file_or_directory)
 977     return EC;
 978
 979   // We failed because of a no_such_file_or_directory, try to create the
 980   // parent.
 981   StringRef Parent = path::parent_path(P);
 982   if (Parent.empty())
 983     return EC;
 984
 985   if ((EC = create_directories(Parent, IgnoreExisting, Perms)))
 986       return EC;
 987
 988   return create_directory(P, IgnoreExisting, Perms);
 989 }
 990
 991 static std::error_code copy_file_internal(int ReadFD, int WriteFD) {
 992   const size_t BufSize = 4096;
 993   char *Buf = new char[BufSize];
 994   int BytesRead = 0, BytesWritten = 0;
 995   for (;;) {
 996     BytesRead = read(ReadFD, Buf, BufSize);
 997     if (BytesRead <= 0)
 998       break;
 999     while (BytesRead) {
1000       BytesWritten = write(WriteFD, Buf, BytesRead);
1001       if (BytesWritten < 0)
1002         break;
1003       BytesRead -= BytesWritten;
1004     }
1005     if (BytesWritten < 0)
1006       break;
1007   }
1008   delete[] Buf;
1009
1010   if (BytesRead < 0 || BytesWritten < 0)
1011     return errnoAsErrorCode();
1012   return std::error_code();
1013 }
1014
1015 #ifndef __APPLE__
1016 std::error_code copy_file(const Twine &From, const Twine &To) {
1017   int ReadFD, WriteFD;
1018   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1019     return EC;
1020   if (std::error_code EC =
1021           openFileForWrite(To, WriteFD, CD_CreateAlways, OF_None)) {
1022     close(ReadFD);
1023     return EC;
1024   }
1025
1026   std::error_code EC = copy_file_internal(ReadFD, WriteFD);
1027
1028   close(ReadFD);
1029   close(WriteFD);
1030
1031   return EC;
1032 }
1033 #endif
1034
1035 std::error_code copy_file(const Twine &From, int ToFD) {
1036   int ReadFD;
1037   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1038     return EC;
1039
1040   std::error_code EC = copy_file_internal(ReadFD, ToFD);
1041
1042   close(ReadFD);
1043
1044   return EC;
1045 }
1046
1047 ErrorOr<MD5::MD5Result> md5_contents(int FD) {
1048   MD5 Hash;
1049
1050   constexpr size_t BufSize = 4096;
1051   std::vector<uint8_t> Buf(BufSize);
1052   int BytesRead = 0;
1053   for (;;) {
1054     BytesRead = read(FD, Buf.data(), BufSize);
1055     if (BytesRead <= 0)
1056       break;
1057     Hash.update(ArrayRef(Buf.data(), BytesRead));
1058   }
1059
1060   if (BytesRead < 0)
1061     return errnoAsErrorCode();
1062   MD5::MD5Result Result;
1063   Hash.final(Result);
1064   return Result;
1065 }
1066
1067 ErrorOr<MD5::MD5Result> md5_contents(const Twine &Path) {
1068   int FD;
1069   if (auto EC = openFileForRead(Path, FD, OF_None))
1070     return EC;
1071
1072   auto Result = md5_contents(FD);
1073   close(FD);
1074   return Result;
1075 }
1076
1077 bool exists(const basic_file_status &status) {
1078   return status_known(status) && status.type() != file_type::file_not_found;
1079 }
1080
1081 bool status_known(const basic_file_status &s) {
1082   return s.type() != file_type::status_error;
1083 }
1084
1085 file_type get_file_type(const Twine &Path, bool Follow) {
1086   file_status st;
1087   if (status(Path, st, Follow))
1088     return file_type::status_error;
1089   return st.type();
1090 }
1091
1092 bool is_directory(const basic_file_status &status) {
1093   return status.type() == file_type::directory_file;
1094 }
1095
1096 std::error_code is_directory(const Twine &path, bool &result) {
1097   file_status st;
1098   if (std::error_code ec = status(path, st))
1099     return ec;
1100   result = is_directory(st);
1101   return std::error_code();
1102 }
1103
1104 bool is_regular_file(const basic_file_status &status) {
1105   return status.type() == file_type::regular_file;
1106 }
1107
1108 std::error_code is_regular_file(const Twine &path, bool &result) {
1109   file_status st;
1110   if (std::error_code ec = status(path, st))
1111     return ec;
1112   result = is_regular_file(st);
1113   return std::error_code();
1114 }
1115
1116 bool is_symlink_file(const basic_file_status &status) {
1117   return status.type() == file_type::symlink_file;
1118 }
1119
1120 std::error_code is_symlink_file(const Twine &path, bool &result) {
1121   file_status st;
1122   if (std::error_code ec = status(path, st, false))
1123     return ec;
1124   result = is_symlink_file(st);
1125   return std::error_code();
1126 }
1127
1128 bool is_other(const basic_file_status &status) {
1129   return exists(status) &&
1130          !is_regular_file(status) &&
1131          !is_directory(status);
1132 }
1133
1134 std::error_code is_other(const Twine &Path, bool &Result) {
1135   file_status FileStatus;
1136   if (std::error_code EC = status(Path, FileStatus))
1137     return EC;
1138   Result = is_other(FileStatus);
1139   return std::error_code();
1140 }
1141
1142 void directory_entry::replace_filename(const Twine &Filename, file_type Type,
1143                                        basic_file_status Status) {
1144   SmallString<128> PathStr = path::parent_path(Path);
1145   path::append(PathStr, Filename);
1146   this->Path = std::string(PathStr);
1147   this->Type = Type;
1148   this->Status = Status;
1149 }
1150
1151 ErrorOr<perms> getPermissions(const Twine &Path) {
1152   file_status Status;
1153   if (std::error_code EC = status(Path, Status))
1154     return EC;
1155
1156   return Status.permissions();
1157 }
1158
1159 size_t mapped_file_region::size() const {
1160   assert(Mapping && "Mapping failed but used anyway!");
1161   return Size;
1162 }
1163
1164 char *mapped_file_region::data() const {
1165   assert(Mapping && "Mapping failed but used anyway!");
1166   return reinterpret_cast<char *>(Mapping);
1167 }
1168
1169 const char *mapped_file_region::const_data() const {
1170   assert(Mapping && "Mapping failed but used anyway!");
1171   return reinterpret_cast<const char *>(Mapping);
1172 }
1173
1174 Error readNativeFileToEOF(file_t FileHandle, SmallVectorImpl<char> &Buffer,
1175                           ssize_t ChunkSize) {
1176   // Install a handler to truncate the buffer to the correct size on exit.
1177   size_t Size = Buffer.size();
1178   auto TruncateOnExit = make_scope_exit([&]() { Buffer.truncate(Size); });
1179
1180   // Read into Buffer until we hit EOF.
1181   for (;;) {
1182     Buffer.resize_for_overwrite(Size + ChunkSize);
1183     Expected<size_t> ReadBytes = readNativeFile(
1184         FileHandle, MutableArrayRef(Buffer.begin() + Size, ChunkSize));
1185     if (!ReadBytes)
1186       return ReadBytes.takeError();
1187     if (*ReadBytes == 0)
1188       return Error::success();
1189     Size += *ReadBytes;
1190   }
1191 }
1192
1193 } // end namespace fs
1194 } // end namespace sys
1195 } // end namespace llvm
1196
1197 // Include the truly platform-specific parts.
1198 #if defined(LLVM_ON_UNIX)
1199 #include "Unix/Path.inc"
1200 #endif
1201 #if defined(_WIN32)
1202 #include "Windows/Path.inc"
1203 #endif
1204
1205 namespace llvm {
1206 namespace sys {
1207 namespace fs {
1208
1209 TempFile::TempFile(StringRef Name, int FD)
1210     : TmpName(std::string(Name)), FD(FD) {}
1211 TempFile::TempFile(TempFile &&Other) { *this = std::move(Other); }
1212 TempFile &TempFile::operator=(TempFile &&Other) {
1213   TmpName = std::move(Other.TmpName);
1214   FD = Other.FD;
1215   Other.Done = true;
1216   Other.FD = -1;
1217 #ifdef _WIN32
1218   RemoveOnClose = Other.RemoveOnClose;
1219   Other.RemoveOnClose = false;
1220 #endif
1221   return *this;
1222 }
1223
1224 TempFile::~TempFile() { assert(Done); }
1225
1226 Error TempFile::discard() {
1227   Done = true;
1228   if (FD != -1 && close(FD) == -1) {
1229     std::error_code EC = errnoAsErrorCode();
1230     return errorCodeToError(EC);
1231   }
1232   FD = -1;
1233
1234 #ifdef _WIN32
1235   // On Windows, closing will remove the file, if we set the delete
1236   // disposition. If not, remove it manually.
1237   bool Remove = RemoveOnClose;
1238 #else
1239   // Always try to remove the file.
1240   bool Remove = true;
1241 #endif
1242   std::error_code RemoveEC;
1243   if (Remove && !TmpName.empty()) {
1244     RemoveEC = fs::remove(TmpName);
1245     sys::DontRemoveFileOnSignal(TmpName);
1246     if (!RemoveEC)
1247       TmpName = "";
1248   } else {
1249     TmpName = "";
1250   }
1251   return errorCodeToError(RemoveEC);
1252 }
1253
1254 Error TempFile::keep(const Twine &Name) {
1255   assert(!Done);
1256   Done = true;
1257   // Always try to close and rename.
1258 #ifdef _WIN32
1259   // If we can't cancel the delete don't rename.
1260   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1261   std::error_code RenameEC =
1262       RemoveOnClose ? std::error_code() : setDeleteDisposition(H, false);
1263   bool ShouldDelete = false;
1264   if (!RenameEC) {
1265     RenameEC = rename_handle(H, Name);
1266     // If rename failed because it's cross-device, copy instead
1267     if (RenameEC ==
1268       std::error_code(ERROR_NOT_SAME_DEVICE, std::system_category())) {
1269       RenameEC = copy_file(TmpName, Name);
1270       ShouldDelete = true;
1271     }
1272   }
1273
1274   // If we can't rename or copy, discard the temporary file.
1275   if (RenameEC)
1276     ShouldDelete = true;
1277   if (ShouldDelete) {
1278     if (!RemoveOnClose)
1279       setDeleteDisposition(H, true);
1280     else
1281       remove(TmpName);
1282   }
1283 #else
1284   std::error_code RenameEC = fs::rename(TmpName, Name);
1285   if (RenameEC) {
1286     // If we can't rename, try to copy to work around cross-device link issues.
1287     RenameEC = sys::fs::copy_file(TmpName, Name);
1288     // If we can't rename or copy, discard the temporary file.
1289     if (RenameEC)
1290       remove(TmpName);
1291   }
1292 #endif
1293   sys::DontRemoveFileOnSignal(TmpName);
1294
1295   if (!RenameEC)
1296     TmpName = "";
1297
1298   if (close(FD) == -1)
1299     return errorCodeToError(errnoAsErrorCode());
1300   FD = -1;
1301
1302   return errorCodeToError(RenameEC);
1303 }
1304
1305 Error TempFile::keep() {
1306   assert(!Done);
1307   Done = true;
1308
1309 #ifdef _WIN32
1310   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1311   if (std::error_code EC = setDeleteDisposition(H, false))
1312     return errorCodeToError(EC);
1313 #endif
1314   sys::DontRemoveFileOnSignal(TmpName);
1315
1316   TmpName = "";
1317
1318   if (close(FD) == -1)
1319     return errorCodeToError(errnoAsErrorCode());
1320   FD = -1;
1321
1322   return Error::success();
1323 }
1324
1325 Expected<TempFile> TempFile::create(const Twine &Model, unsigned Mode,
1326                                     OpenFlags ExtraFlags) {
1327   int FD;
1328   SmallString<128> ResultPath;
1329   if (std::error_code EC =
1330           createUniqueFile(Model, FD, ResultPath, OF_Delete | ExtraFlags, Mode))
1331     return errorCodeToError(EC);
1332
1333   TempFile Ret(ResultPath, FD);
1334 #ifdef _WIN32
1335   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1336   bool SetSignalHandler = false;
1337   if (std::error_code EC = setDeleteDisposition(H, true)) {
1338     Ret.RemoveOnClose = true;
1339     SetSignalHandler = true;
1340   }
1341 #else
1342   bool SetSignalHandler = true;
1343 #endif
1344   if (SetSignalHandler && sys::RemoveFileOnSignal(ResultPath)) {
1345     // Make sure we delete the file when RemoveFileOnSignal fails.
1346     consumeError(Ret.discard());
1347     std::error_code EC(errc::operation_not_permitted);
1348     return errorCodeToError(EC);
1349   }
1350   return std::move(Ret);
1351 }
1352 } // namespace fs
1353
1354 } // namespace sys
1355 } // namespace llvm