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/Endian.h"
  20 #include "llvm/Support/Errc.h"
  21 #include "llvm/Support/ErrorHandling.h"
  22 #include "llvm/Support/FileSystem.h"
  23 #include "llvm/Support/Process.h"
  24 #include "llvm/Support/Signals.h"
  25 #include <cctype>
  26 #include <cerrno>
  27
  28 #if !defined(_MSC_VER) && !defined(__MINGW32__)
  29 #include <unistd.h>
  30 #else
  31 #include <io.h>
  32 #endif
  33
  34 using namespace llvm;
  35 using namespace llvm::support::endian;
  36
  37 namespace {
  38   using llvm::StringRef;
  39   using llvm::sys::path::is_separator;
  40   using llvm::sys::path::Style;
  41
  42   inline Style real_style(Style style) {
  43     if (style != Style::native)
  44       return style;
  45     if (is_style_posix(style))
  46       return Style::posix;
  47     return LLVM_WINDOWS_PREFER_FORWARD_SLASH ? Style::windows_slash
  48                                              : Style::windows_backslash;
  49   }
  50
  51   inline const char *separators(Style style) {
  52     if (is_style_windows(style))
  53       return "\\/";
  54     return "/";
  55   }
  56
  57   inline char preferred_separator(Style style) {
  58     if (real_style(style) == Style::windows)
  59       return '\\';
  60     return '/';
  61   }
  62
  63   StringRef find_first_component(StringRef path, Style style) {
  64     // Look for this first component in the following order.
  65     // * empty (in this case we return an empty string)
  66     // * either C: or {//,\\}net.
  67     // * {/,\}
  68     // * {file,directory}name
  69
  70     if (path.empty())
  71       return path;
  72
  73     if (is_style_windows(style)) {
  74       // C:
  75       if (path.size() >= 2 &&
  76           std::isalpha(static_cast<unsigned char>(path[0])) && path[1] == ':')
  77         return path.substr(0, 2);
  78     }
  79
  80     // //net
  81     if ((path.size() > 2) && is_separator(path[0], style) &&
  82         path[0] == path[1] && !is_separator(path[2], style)) {
  83       // Find the next directory separator.
  84       size_t end = path.find_first_of(separators(style), 2);
  85       return path.substr(0, end);
  86     }
  87
  88     // {/,\}
  89     if (is_separator(path[0], style))
  90       return path.substr(0, 1);
  91
  92     // * {file,directory}name
  93     size_t end = path.find_first_of(separators(style));
  94     return path.substr(0, end);
  95   }
  96
  97   // Returns the first character of the filename in str. For paths ending in
  98   // '/', it returns the position of the '/'.
  99   size_t filename_pos(StringRef str, Style style) {
 100     if (str.size() > 0 && is_separator(str[str.size() - 1], style))
 101       return str.size() - 1;
 102
 103     size_t pos = str.find_last_of(separators(style), str.size() - 1);
 104
 105     if (is_style_windows(style)) {
 106       if (pos == StringRef::npos)
 107         pos = str.find_last_of(':', str.size() - 1);
 108     }
 109
 110     if (pos == StringRef::npos || (pos == 1 && is_separator(str[0], style)))
 111       return 0;
 112
 113     return pos + 1;
 114   }
 115
 116   // Returns the position of the root directory in str. If there is no root
 117   // directory in str, it returns StringRef::npos.
 118   size_t root_dir_start(StringRef str, Style style) {
 119     // case "c:/"
 120     if (is_style_windows(style)) {
 121       if (str.size() > 2 && str[1] == ':' && is_separator(str[2], style))
 122         return 2;
 123     }
 124
 125     // case "//net"
 126     if (str.size() > 3 && is_separator(str[0], style) && str[0] == str[1] &&
 127         !is_separator(str[2], style)) {
 128       return str.find_first_of(separators(style), 2);
 129     }
 130
 131     // case "/"
 132     if (str.size() > 0 && is_separator(str[0], style))
 133       return 0;
 134
 135     return StringRef::npos;
 136   }
 137
 138   // Returns the position past the end of the "parent path" of path. The parent
 139   // path will not end in '/', unless the parent is the root directory. If the
 140   // path has no parent, 0 is returned.
 141   size_t parent_path_end(StringRef path, Style style) {
 142     size_t end_pos = filename_pos(path, style);
 143
 144     bool filename_was_sep =
 145         path.size() > 0 && is_separator(path[end_pos], style);
 146
 147     // Skip separators until we reach root dir (or the start of the string).
 148     size_t root_dir_pos = root_dir_start(path, style);
 149     while (end_pos > 0 &&
 150            (root_dir_pos == StringRef::npos || end_pos > root_dir_pos) &&
 151            is_separator(path[end_pos - 1], style))
 152       --end_pos;
 153
 154     if (end_pos == root_dir_pos && !filename_was_sep) {
 155       // We've reached the root dir and the input path was *not* ending in a
 156       // sequence of slashes. Include the root dir in the parent path.
 157       return root_dir_pos + 1;
 158     }
 159
 160     // Otherwise, just include before the last slash.
 161     return end_pos;
 162   }
 163 } // end unnamed namespace
 164
 165 enum FSEntity {
 166   FS_Dir,
 167   FS_File,
 168   FS_Name
 169 };
 170
 171 static std::error_code
 172 createUniqueEntity(const Twine &Model, int &ResultFD,
 173                    SmallVectorImpl<char> &ResultPath, bool MakeAbsolute,
 174                    FSEntity Type, sys::fs::OpenFlags Flags = sys::fs::OF_None,
 175                    unsigned Mode = 0) {
 176
 177   // Limit the number of attempts we make, so that we don't infinite loop. E.g.
 178   // "permission denied" could be for a specific file (so we retry with a
 179   // different name) or for the whole directory (retry would always fail).
 180   // Checking which is racy, so we try a number of times, then give up.
 181   std::error_code EC;
 182   for (int Retries = 128; Retries > 0; --Retries) {
 183     sys::fs::createUniquePath(Model, ResultPath, MakeAbsolute);
 184     // Try to open + create the file.
 185     switch (Type) {
 186     case FS_File: {
 187       EC = sys::fs::openFileForReadWrite(Twine(ResultPath.begin()), ResultFD,
 188                                          sys::fs::CD_CreateNew, Flags, Mode);
 189       if (EC) {
 190         // errc::permission_denied happens on Windows when we try to open a file
 191         // that has been marked for deletion.
 192         if (EC == errc::file_exists || EC == errc::permission_denied)
 193           continue;
 194         return EC;
 195       }
 196
 197       return std::error_code();
 198     }
 199
 200     case FS_Name: {
 201       EC = sys::fs::access(ResultPath.begin(), sys::fs::AccessMode::Exist);
 202       if (EC == errc::no_such_file_or_directory)
 203         return std::error_code();
 204       if (EC)
 205         return EC;
 206       continue;
 207     }
 208
 209     case FS_Dir: {
 210       EC = sys::fs::create_directory(ResultPath.begin(), false);
 211       if (EC) {
 212         if (EC == errc::file_exists)
 213           continue;
 214         return EC;
 215       }
 216       return std::error_code();
 217     }
 218     }
 219     llvm_unreachable("Invalid Type");
 220   }
 221   return EC;
 222 }
 223
 224 namespace llvm {
 225 namespace sys  {
 226 namespace path {
 227
 228 const_iterator begin(StringRef path, Style style) {
 229   const_iterator i;
 230   i.Path      = path;
 231   i.Component = find_first_component(path, style);
 232   i.Position  = 0;
 233   i.S = style;
 234   return i;
 235 }
 236
 237 const_iterator end(StringRef path) {
 238   const_iterator i;
 239   i.Path      = path;
 240   i.Position  = path.size();
 241   return i;
 242 }
 243
 244 const_iterator &const_iterator::operator++() {
 245   assert(Position < Path.size() && "Tried to increment past end!");
 246
 247   // Increment Position to past the current component
 248   Position += Component.size();
 249
 250   // Check for end.
 251   if (Position == Path.size()) {
 252     Component = StringRef();
 253     return *this;
 254   }
 255
 256   // Both POSIX and Windows treat paths that begin with exactly two separators
 257   // specially.
 258   bool was_net = Component.size() > 2 && is_separator(Component[0], S) &&
 259                  Component[1] == Component[0] && !is_separator(Component[2], S);
 260
 261   // Handle separators.
 262   if (is_separator(Path[Position], S)) {
 263     // Root dir.
 264     if (was_net ||
 265         // c:/
 266         (is_style_windows(S) && Component.ends_with(":"))) {
 267       Component = Path.substr(Position, 1);
 268       return *this;
 269     }
 270
 271     // Skip extra separators.
 272     while (Position != Path.size() && is_separator(Path[Position], S)) {
 273       ++Position;
 274     }
 275
 276     // Treat trailing '/' as a '.', unless it is the root dir.
 277     if (Position == Path.size() && Component != "/") {
 278       --Position;
 279       Component = ".";
 280       return *this;
 281     }
 282   }
 283
 284   // Find next component.
 285   size_t end_pos = Path.find_first_of(separators(S), Position);
 286   Component = Path.slice(Position, end_pos);
 287
 288   return *this;
 289 }
 290
 291 bool const_iterator::operator==(const const_iterator &RHS) const {
 292   return Path.begin() == RHS.Path.begin() && Position == RHS.Position;
 293 }
 294
 295 ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
 296   return Position - RHS.Position;
 297 }
 298
 299 reverse_iterator rbegin(StringRef Path, Style style) {
 300   reverse_iterator I;
 301   I.Path = Path;
 302   I.Position = Path.size();
 303   I.S = style;
 304   ++I;
 305   return I;
 306 }
 307
 308 reverse_iterator rend(StringRef Path) {
 309   reverse_iterator I;
 310   I.Path = Path;
 311   I.Component = Path.substr(0, 0);
 312   I.Position = 0;
 313   return I;
 314 }
 315
 316 reverse_iterator &reverse_iterator::operator++() {
 317   size_t root_dir_pos = root_dir_start(Path, S);
 318
 319   // Skip separators unless it's the root directory.
 320   size_t end_pos = Position;
 321   while (end_pos > 0 && (end_pos - 1) != root_dir_pos &&
 322          is_separator(Path[end_pos - 1], S))
 323     --end_pos;
 324
 325   // Treat trailing '/' as a '.', unless it is the root dir.
 326   if (Position == Path.size() && !Path.empty() &&
 327       is_separator(Path.back(), S) &&
 328       (root_dir_pos == StringRef::npos || end_pos - 1 > root_dir_pos)) {
 329     --Position;
 330     Component = ".";
 331     return *this;
 332   }
 333
 334   // Find next separator.
 335   size_t start_pos = filename_pos(Path.substr(0, end_pos), S);
 336   Component = Path.slice(start_pos, end_pos);
 337   Position = start_pos;
 338   return *this;
 339 }
 340
 341 bool reverse_iterator::operator==(const reverse_iterator &RHS) const {
 342   return Path.begin() == RHS.Path.begin() && Component == RHS.Component &&
 343          Position == RHS.Position;
 344 }
 345
 346 ptrdiff_t reverse_iterator::operator-(const reverse_iterator &RHS) const {
 347   return Position - RHS.Position;
 348 }
 349
 350 StringRef root_path(StringRef path, Style style) {
 351   const_iterator b = begin(path, style), pos = b, e = end(path);
 352   if (b != e) {
 353     bool has_net =
 354         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 355     bool has_drive = is_style_windows(style) && b->ends_with(":");
 356
 357     if (has_net || has_drive) {
 358       if ((++pos != e) && is_separator((*pos)[0], style)) {
 359         // {C:/,//net/}, so get the first two components.
 360         return path.substr(0, b->size() + pos->size());
 361       }
 362       // just {C:,//net}, return the first component.
 363       return *b;
 364     }
 365
 366     // POSIX style root directory.
 367     if (is_separator((*b)[0], style)) {
 368       return *b;
 369     }
 370   }
 371
 372   return StringRef();
 373 }
 374
 375 StringRef root_name(StringRef path, Style style) {
 376   const_iterator b = begin(path, style), e = end(path);
 377   if (b != e) {
 378     bool has_net =
 379         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 380     bool has_drive = is_style_windows(style) && b->ends_with(":");
 381
 382     if (has_net || has_drive) {
 383       // just {C:,//net}, return the first component.
 384       return *b;
 385     }
 386   }
 387
 388   // No path or no name.
 389   return StringRef();
 390 }
 391
 392 StringRef root_directory(StringRef path, Style style) {
 393   const_iterator b = begin(path, style), pos = b, e = end(path);
 394   if (b != e) {
 395     bool has_net =
 396         b->size() > 2 && is_separator((*b)[0], style) && (*b)[1] == (*b)[0];
 397     bool has_drive = is_style_windows(style) && b->ends_with(":");
 398
 399     if ((has_net || has_drive) &&
 400         // {C:,//net}, skip to the next component.
 401         (++pos != e) && is_separator((*pos)[0], style)) {
 402       return *pos;
 403     }
 404
 405     // POSIX style root directory.
 406     if (!has_net && is_separator((*b)[0], style)) {
 407       return *b;
 408     }
 409   }
 410
 411   // No path or no root.
 412   return StringRef();
 413 }
 414
 415 StringRef relative_path(StringRef path, Style style) {
 416   StringRef root = root_path(path, style);
 417   return path.substr(root.size());
 418 }
 419
 420 void append(SmallVectorImpl<char> &path, Style style, const Twine &a,
 421             const Twine &b, const Twine &c, const Twine &d) {
 422   SmallString<32> a_storage;
 423   SmallString<32> b_storage;
 424   SmallString<32> c_storage;
 425   SmallString<32> d_storage;
 426
 427   SmallVector<StringRef, 4> components;
 428   if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
 429   if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
 430   if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
 431   if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
 432
 433   for (auto &component : components) {
 434     bool path_has_sep =
 435         !path.empty() && is_separator(path[path.size() - 1], style);
 436     if (path_has_sep) {
 437       // Strip separators from beginning of component.
 438       size_t loc = component.find_first_not_of(separators(style));
 439       StringRef c = component.substr(loc);
 440
 441       // Append it.
 442       path.append(c.begin(), c.end());
 443       continue;
 444     }
 445
 446     bool component_has_sep =
 447         !component.empty() && is_separator(component[0], style);
 448     if (!component_has_sep &&
 449         !(path.empty() || has_root_name(component, style))) {
 450       // Add a separator.
 451       path.push_back(preferred_separator(style));
 452     }
 453
 454     path.append(component.begin(), component.end());
 455   }
 456 }
 457
 458 void append(SmallVectorImpl<char> &path, const Twine &a, const Twine &b,
 459             const Twine &c, const Twine &d) {
 460   append(path, Style::native, a, b, c, d);
 461 }
 462
 463 void append(SmallVectorImpl<char> &path, const_iterator begin,
 464             const_iterator end, Style style) {
 465   for (; begin != end; ++begin)
 466     path::append(path, style, *begin);
 467 }
 468
 469 StringRef parent_path(StringRef path, Style style) {
 470   size_t end_pos = parent_path_end(path, style);
 471   if (end_pos == StringRef::npos)
 472     return StringRef();
 473   return path.substr(0, end_pos);
 474 }
 475
 476 void remove_filename(SmallVectorImpl<char> &path, Style style) {
 477   size_t end_pos = parent_path_end(StringRef(path.begin(), path.size()), style);
 478   if (end_pos != StringRef::npos)
 479     path.truncate(end_pos);
 480 }
 481
 482 void replace_extension(SmallVectorImpl<char> &path, const Twine &extension,
 483                        Style style) {
 484   StringRef p(path.begin(), path.size());
 485   SmallString<32> ext_storage;
 486   StringRef ext = extension.toStringRef(ext_storage);
 487
 488   // Erase existing extension.
 489   size_t pos = p.find_last_of('.');
 490   if (pos != StringRef::npos && pos >= filename_pos(p, style))
 491     path.truncate(pos);
 492
 493   // Append '.' if needed.
 494   if (ext.size() > 0 && ext[0] != '.')
 495     path.push_back('.');
 496
 497   // Append extension.
 498   path.append(ext.begin(), ext.end());
 499 }
 500
 501 static bool starts_with(StringRef Path, StringRef Prefix,
 502                         Style style = Style::native) {
 503   // Windows prefix matching : case and separator insensitive
 504   if (is_style_windows(style)) {
 505     if (Path.size() < Prefix.size())
 506       return false;
 507     for (size_t I = 0, E = Prefix.size(); I != E; ++I) {
 508       bool SepPath = is_separator(Path[I], style);
 509       bool SepPrefix = is_separator(Prefix[I], style);
 510       if (SepPath != SepPrefix)
 511         return false;
 512       if (!SepPath && toLower(Path[I]) != toLower(Prefix[I]))
 513         return false;
 514     }
 515     return true;
 516   }
 517   return Path.starts_with(Prefix);
 518 }
 519
 520 bool replace_path_prefix(SmallVectorImpl<char> &Path, StringRef OldPrefix,
 521                          StringRef NewPrefix, Style style) {
 522   if (OldPrefix.empty() && NewPrefix.empty())
 523     return false;
 524
 525   StringRef OrigPath(Path.begin(), Path.size());
 526   if (!starts_with(OrigPath, OldPrefix, style))
 527     return false;
 528
 529   // If prefixes have the same size we can simply copy the new one over.
 530   if (OldPrefix.size() == NewPrefix.size()) {
 531     llvm::copy(NewPrefix, Path.begin());
 532     return true;
 533   }
 534
 535   StringRef RelPath = OrigPath.substr(OldPrefix.size());
 536   SmallString<256> NewPath;
 537   (Twine(NewPrefix) + RelPath).toVector(NewPath);
 538   Path.swap(NewPath);
 539   return true;
 540 }
 541
 542 void native(const Twine &path, SmallVectorImpl<char> &result, Style style) {
 543   assert((!path.isSingleStringRef() ||
 544           path.getSingleStringRef().data() != result.data()) &&
 545          "path and result are not allowed to overlap!");
 546   // Clear result.
 547   result.clear();
 548   path.toVector(result);
 549   native(result, style);
 550 }
 551
 552 void native(SmallVectorImpl<char> &Path, Style style) {
 553   if (Path.empty())
 554     return;
 555   if (is_style_windows(style)) {
 556     for (char &Ch : Path)
 557       if (is_separator(Ch, style))
 558         Ch = preferred_separator(style);
 559     if (Path[0] == '~' && (Path.size() == 1 || is_separator(Path[1], style))) {
 560       SmallString<128> PathHome;
 561       home_directory(PathHome);
 562       PathHome.append(Path.begin() + 1, Path.end());
 563       Path = PathHome;
 564     }
 565   } else {
 566     std::replace(Path.begin(), Path.end(), '\\', '/');
 567   }
 568 }
 569
 570 std::string convert_to_slash(StringRef path, Style style) {
 571   if (is_style_posix(style))
 572     return std::string(path);
 573
 574   std::string s = path.str();
 575   std::replace(s.begin(), s.end(), '\\', '/');
 576   return s;
 577 }
 578
 579 StringRef filename(StringRef path, Style style) { return *rbegin(path, style); }
 580
 581 StringRef stem(StringRef path, Style style) {
 582   StringRef fname = filename(path, style);
 583   size_t pos = fname.find_last_of('.');
 584   if (pos == StringRef::npos)
 585     return fname;
 586   if ((fname.size() == 1 && fname == ".") ||
 587       (fname.size() == 2 && fname == ".."))
 588     return fname;
 589   return fname.substr(0, pos);
 590 }
 591
 592 StringRef extension(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 StringRef();
 597   if ((fname.size() == 1 && fname == ".") ||
 598       (fname.size() == 2 && fname == ".."))
 599     return StringRef();
 600   return fname.substr(pos);
 601 }
 602
 603 bool is_separator(char value, Style style) {
 604   if (value == '/')
 605     return true;
 606   if (is_style_windows(style))
 607     return value == '\\';
 608   return false;
 609 }
 610
 611 StringRef get_separator(Style style) {
 612   if (real_style(style) == Style::windows)
 613     return "\\";
 614   return "/";
 615 }
 616
 617 bool has_root_name(const Twine &path, Style style) {
 618   SmallString<128> path_storage;
 619   StringRef p = path.toStringRef(path_storage);
 620
 621   return !root_name(p, style).empty();
 622 }
 623
 624 bool has_root_directory(const Twine &path, Style style) {
 625   SmallString<128> path_storage;
 626   StringRef p = path.toStringRef(path_storage);
 627
 628   return !root_directory(p, style).empty();
 629 }
 630
 631 bool has_root_path(const Twine &path, Style style) {
 632   SmallString<128> path_storage;
 633   StringRef p = path.toStringRef(path_storage);
 634
 635   return !root_path(p, style).empty();
 636 }
 637
 638 bool has_relative_path(const Twine &path, Style style) {
 639   SmallString<128> path_storage;
 640   StringRef p = path.toStringRef(path_storage);
 641
 642   return !relative_path(p, style).empty();
 643 }
 644
 645 bool has_filename(const Twine &path, Style style) {
 646   SmallString<128> path_storage;
 647   StringRef p = path.toStringRef(path_storage);
 648
 649   return !filename(p, style).empty();
 650 }
 651
 652 bool has_parent_path(const Twine &path, Style style) {
 653   SmallString<128> path_storage;
 654   StringRef p = path.toStringRef(path_storage);
 655
 656   return !parent_path(p, style).empty();
 657 }
 658
 659 bool has_stem(const Twine &path, Style style) {
 660   SmallString<128> path_storage;
 661   StringRef p = path.toStringRef(path_storage);
 662
 663   return !stem(p, style).empty();
 664 }
 665
 666 bool has_extension(const Twine &path, Style style) {
 667   SmallString<128> path_storage;
 668   StringRef p = path.toStringRef(path_storage);
 669
 670   return !extension(p, style).empty();
 671 }
 672
 673 bool is_absolute(const Twine &path, Style style) {
 674   SmallString<128> path_storage;
 675   StringRef p = path.toStringRef(path_storage);
 676
 677   bool rootDir = has_root_directory(p, style);
 678   bool rootName = is_style_posix(style) || has_root_name(p, style);
 679
 680   return rootDir && rootName;
 681 }
 682
 683 bool is_absolute_gnu(const Twine &path, Style style) {
 684   SmallString<128> path_storage;
 685   StringRef p = path.toStringRef(path_storage);
 686
 687   // Handle '/' which is absolute for both Windows and POSIX systems.
 688   // Handle '\\' on Windows.
 689   if (!p.empty() && is_separator(p.front(), style))
 690     return true;
 691
 692   if (is_style_windows(style)) {
 693     // Handle drive letter pattern (a character followed by ':') on Windows.
 694     if (p.size() >= 2 && (p[0] && p[1] == ':'))
 695       return true;
 696   }
 697
 698   return false;
 699 }
 700
 701 bool is_relative(const Twine &path, Style style) {
 702   return !is_absolute(path, style);
 703 }
 704
 705 StringRef remove_leading_dotslash(StringRef Path, Style style) {
 706   // Remove leading "./" (or ".//" or "././" etc.)
 707   while (Path.size() > 2 && Path[0] == '.' && is_separator(Path[1], style)) {
 708     Path = Path.substr(2);
 709     while (Path.size() > 0 && is_separator(Path[0], style))
 710       Path = Path.substr(1);
 711   }
 712   return Path;
 713 }
 714
 715 // Remove path traversal components ("." and "..") when possible, and
 716 // canonicalize slashes.
 717 bool remove_dots(SmallVectorImpl<char> &the_path, bool remove_dot_dot,
 718                  Style style) {
 719   style = real_style(style);
 720   StringRef remaining(the_path.data(), the_path.size());
 721   bool needs_change = false;
 722   SmallVector<StringRef, 16> components;
 723
 724   // Consume the root path, if present.
 725   StringRef root = path::root_path(remaining, style);
 726   bool absolute = !root.empty();
 727   if (absolute)
 728     remaining = remaining.drop_front(root.size());
 729
 730   // Loop over path components manually. This makes it easier to detect
 731   // non-preferred slashes and double separators that must be canonicalized.
 732   while (!remaining.empty()) {
 733     size_t next_slash = remaining.find_first_of(separators(style));
 734     if (next_slash == StringRef::npos)
 735       next_slash = remaining.size();
 736     StringRef component = remaining.take_front(next_slash);
 737     remaining = remaining.drop_front(next_slash);
 738
 739     // Eat the slash, and check if it is the preferred separator.
 740     if (!remaining.empty()) {
 741       needs_change |= remaining.front() != preferred_separator(style);
 742       remaining = remaining.drop_front();
 743       // The path needs to be rewritten if it has a trailing slash.
 744       // FIXME: This is emergent behavior that could be removed.
 745       needs_change |= remaining.empty();
 746     }
 747
 748     // Check for path traversal components or double separators.
 749     if (component.empty() || component == ".") {
 750       needs_change = true;
 751     } else if (remove_dot_dot && component == "..") {
 752       needs_change = true;
 753       // Do not allow ".." to remove the root component. If this is the
 754       // beginning of a relative path, keep the ".." component.
 755       if (!components.empty() && components.back() != "..") {
 756         components.pop_back();
 757       } else if (!absolute) {
 758         components.push_back(component);
 759       }
 760     } else {
 761       components.push_back(component);
 762     }
 763   }
 764
 765   SmallString<256> buffer = root;
 766   // "root" could be "/", which may need to be translated into "\".
 767   make_preferred(buffer, style);
 768   needs_change |= root != buffer;
 769
 770   // Avoid rewriting the path unless we have to.
 771   if (!needs_change)
 772     return false;
 773
 774   if (!components.empty()) {
 775     buffer += components[0];
 776     for (StringRef C : ArrayRef(components).drop_front()) {
 777       buffer += preferred_separator(style);
 778       buffer += C;
 779     }
 780   }
 781   the_path.swap(buffer);
 782   return true;
 783 }
 784
 785 } // end namespace path
 786
 787 namespace fs {
 788
 789 std::error_code getUniqueID(const Twine Path, UniqueID &Result) {
 790   file_status Status;
 791   std::error_code EC = status(Path, Status);
 792   if (EC)
 793     return EC;
 794   Result = Status.getUniqueID();
 795   return std::error_code();
 796 }
 797
 798 void createUniquePath(const Twine &Model, SmallVectorImpl<char> &ResultPath,
 799                       bool MakeAbsolute) {
 800   SmallString<128> ModelStorage;
 801   Model.toVector(ModelStorage);
 802
 803   if (MakeAbsolute) {
 804     // Make model absolute by prepending a temp directory if it's not already.
 805     if (!sys::path::is_absolute(Twine(ModelStorage))) {
 806       SmallString<128> TDir;
 807       sys::path::system_temp_directory(true, TDir);
 808       sys::path::append(TDir, Twine(ModelStorage));
 809       ModelStorage.swap(TDir);
 810     }
 811   }
 812
 813   ResultPath = ModelStorage;
 814   ResultPath.push_back(0);
 815   ResultPath.pop_back();
 816
 817   // Replace '%' with random chars.
 818   for (unsigned i = 0, e = ModelStorage.size(); i != e; ++i) {
 819     if (ModelStorage[i] == '%')
 820       ResultPath[i] = "0123456789abcdef"[sys::Process::GetRandomNumber() & 15];
 821   }
 822 }
 823
 824 std::error_code createUniqueFile(const Twine &Model, int &ResultFd,
 825                                  SmallVectorImpl<char> &ResultPath,
 826                                  OpenFlags Flags, unsigned Mode) {
 827   return createUniqueEntity(Model, ResultFd, ResultPath, false, FS_File, Flags,
 828                             Mode);
 829 }
 830
 831 std::error_code createUniqueFile(const Twine &Model,
 832                                  SmallVectorImpl<char> &ResultPath,
 833                                  unsigned Mode) {
 834   int FD;
 835   auto EC = createUniqueFile(Model, FD, ResultPath, OF_None, Mode);
 836   if (EC)
 837     return EC;
 838   // FD is only needed to avoid race conditions. Close it right away.
 839   close(FD);
 840   return EC;
 841 }
 842
 843 static std::error_code
 844 createTemporaryFile(const Twine &Model, int &ResultFD,
 845                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type,
 846                     sys::fs::OpenFlags Flags = sys::fs::OF_None) {
 847   SmallString<128> Storage;
 848   StringRef P = Model.toNullTerminatedStringRef(Storage);
 849   assert(P.find_first_of(separators(Style::native)) == StringRef::npos &&
 850          "Model must be a simple filename.");
 851   // Use P.begin() so that createUniqueEntity doesn't need to recreate Storage.
 852   return createUniqueEntity(P.begin(), ResultFD, ResultPath, true, Type, Flags,
 853                             owner_read | owner_write);
 854 }
 855
 856 static std::error_code
 857 createTemporaryFile(const Twine &Prefix, StringRef Suffix, int &ResultFD,
 858                     llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type,
 859                     sys::fs::OpenFlags Flags = sys::fs::OF_None) {
 860   const char *Middle = Suffix.empty() ? "-%%%%%%" : "-%%%%%%.";
 861   return createTemporaryFile(Prefix + Middle + Suffix, ResultFD, ResultPath,
 862                              Type, Flags);
 863 }
 864
 865 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 866                                     int &ResultFD,
 867                                     SmallVectorImpl<char> &ResultPath,
 868                                     sys::fs::OpenFlags Flags) {
 869   return createTemporaryFile(Prefix, Suffix, ResultFD, ResultPath, FS_File,
 870                              Flags);
 871 }
 872
 873 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 874                                     SmallVectorImpl<char> &ResultPath,
 875                                     sys::fs::OpenFlags Flags) {
 876   int FD;
 877   auto EC = createTemporaryFile(Prefix, Suffix, FD, ResultPath, Flags);
 878   if (EC)
 879     return EC;
 880   // FD is only needed to avoid race conditions. Close it right away.
 881   close(FD);
 882   return EC;
 883 }
 884
 885 // This is a mkdtemp with a different pattern. We use createUniqueEntity mostly
 886 // for consistency. We should try using mkdtemp.
 887 std::error_code createUniqueDirectory(const Twine &Prefix,
 888                                       SmallVectorImpl<char> &ResultPath) {
 889   int Dummy;
 890   return createUniqueEntity(Prefix + "-%%%%%%", Dummy, ResultPath, true,
 891                             FS_Dir);
 892 }
 893
 894 std::error_code
 895 getPotentiallyUniqueFileName(const Twine &Model,
 896                              SmallVectorImpl<char> &ResultPath) {
 897   int Dummy;
 898   return createUniqueEntity(Model, Dummy, ResultPath, false, FS_Name);
 899 }
 900
 901 std::error_code
 902 getPotentiallyUniqueTempFileName(const Twine &Prefix, StringRef Suffix,
 903                                  SmallVectorImpl<char> &ResultPath) {
 904   int Dummy;
 905   return createTemporaryFile(Prefix, Suffix, Dummy, ResultPath, FS_Name);
 906 }
 907
 908 void make_absolute(const Twine &current_directory,
 909                    SmallVectorImpl<char> &path) {
 910   StringRef p(path.data(), path.size());
 911
 912   bool rootDirectory = path::has_root_directory(p);
 913   bool rootName = path::has_root_name(p);
 914
 915   // Already absolute.
 916   if ((rootName || is_style_posix(Style::native)) && rootDirectory)
 917     return;
 918
 919   // All of the following conditions will need the current directory.
 920   SmallString<128> current_dir;
 921   current_directory.toVector(current_dir);
 922
 923   // Relative path. Prepend the current directory.
 924   if (!rootName && !rootDirectory) {
 925     // Append path to the current directory.
 926     path::append(current_dir, p);
 927     // Set path to the result.
 928     path.swap(current_dir);
 929     return;
 930   }
 931
 932   if (!rootName && rootDirectory) {
 933     StringRef cdrn = path::root_name(current_dir);
 934     SmallString<128> curDirRootName(cdrn.begin(), cdrn.end());
 935     path::append(curDirRootName, p);
 936     // Set path to the result.
 937     path.swap(curDirRootName);
 938     return;
 939   }
 940
 941   if (rootName && !rootDirectory) {
 942     StringRef pRootName      = path::root_name(p);
 943     StringRef bRootDirectory = path::root_directory(current_dir);
 944     StringRef bRelativePath  = path::relative_path(current_dir);
 945     StringRef pRelativePath  = path::relative_path(p);
 946
 947     SmallString<128> res;
 948     path::append(res, pRootName, bRootDirectory, bRelativePath, pRelativePath);
 949     path.swap(res);
 950     return;
 951   }
 952
 953   llvm_unreachable("All rootName and rootDirectory combinations should have "
 954                    "occurred above!");
 955 }
 956
 957 std::error_code make_absolute(SmallVectorImpl<char> &path) {
 958   if (path::is_absolute(path))
 959     return {};
 960
 961   SmallString<128> current_dir;
 962   if (std::error_code ec = current_path(current_dir))
 963     return ec;
 964
 965   make_absolute(current_dir, path);
 966   return {};
 967 }
 968
 969 std::error_code create_directories(const Twine &Path, bool IgnoreExisting,
 970                                    perms Perms) {
 971   SmallString<128> PathStorage;
 972   StringRef P = Path.toStringRef(PathStorage);
 973
 974   // Be optimistic and try to create the directory
 975   std::error_code EC = create_directory(P, IgnoreExisting, Perms);
 976   // If we succeeded, or had any error other than the parent not existing, just
 977   // return it.
 978   if (EC != errc::no_such_file_or_directory)
 979     return EC;
 980
 981   // We failed because of a no_such_file_or_directory, try to create the
 982   // parent.
 983   StringRef Parent = path::parent_path(P);
 984   if (Parent.empty())
 985     return EC;
 986
 987   if ((EC = create_directories(Parent, IgnoreExisting, Perms)))
 988       return EC;
 989
 990   return create_directory(P, IgnoreExisting, Perms);
 991 }
 992
 993 static std::error_code copy_file_internal(int ReadFD, int WriteFD) {
 994   const size_t BufSize = 4096;
 995   char *Buf = new char[BufSize];
 996   int BytesRead = 0, BytesWritten = 0;
 997   for (;;) {
 998     BytesRead = read(ReadFD, Buf, BufSize);
 999     if (BytesRead <= 0)
1000       break;
1001     while (BytesRead) {
1002       BytesWritten = write(WriteFD, Buf, BytesRead);
1003       if (BytesWritten < 0)
1004         break;
1005       BytesRead -= BytesWritten;
1006     }
1007     if (BytesWritten < 0)
1008       break;
1009   }
1010   delete[] Buf;
1011
1012   if (BytesRead < 0 || BytesWritten < 0)
1013     return std::error_code(errno, std::generic_category());
1014   return std::error_code();
1015 }
1016
1017 #ifndef __APPLE__
1018 std::error_code copy_file(const Twine &From, const Twine &To) {
1019   int ReadFD, WriteFD;
1020   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1021     return EC;
1022   if (std::error_code EC =
1023           openFileForWrite(To, WriteFD, CD_CreateAlways, OF_None)) {
1024     close(ReadFD);
1025     return EC;
1026   }
1027
1028   std::error_code EC = copy_file_internal(ReadFD, WriteFD);
1029
1030   close(ReadFD);
1031   close(WriteFD);
1032
1033   return EC;
1034 }
1035 #endif
1036
1037 std::error_code copy_file(const Twine &From, int ToFD) {
1038   int ReadFD;
1039   if (std::error_code EC = openFileForRead(From, ReadFD, OF_None))
1040     return EC;
1041
1042   std::error_code EC = copy_file_internal(ReadFD, ToFD);
1043
1044   close(ReadFD);
1045
1046   return EC;
1047 }
1048
1049 ErrorOr<MD5::MD5Result> md5_contents(int FD) {
1050   MD5 Hash;
1051
1052   constexpr size_t BufSize = 4096;
1053   std::vector<uint8_t> Buf(BufSize);
1054   int BytesRead = 0;
1055   for (;;) {
1056     BytesRead = read(FD, Buf.data(), BufSize);
1057     if (BytesRead <= 0)
1058       break;
1059     Hash.update(ArrayRef(Buf.data(), BytesRead));
1060   }
1061
1062   if (BytesRead < 0)
1063     return std::error_code(errno, std::generic_category());
1064   MD5::MD5Result Result;
1065   Hash.final(Result);
1066   return Result;
1067 }
1068
1069 ErrorOr<MD5::MD5Result> md5_contents(const Twine &Path) {
1070   int FD;
1071   if (auto EC = openFileForRead(Path, FD, OF_None))
1072     return EC;
1073
1074   auto Result = md5_contents(FD);
1075   close(FD);
1076   return Result;
1077 }
1078
1079 bool exists(const basic_file_status &status) {
1080   return status_known(status) && status.type() != file_type::file_not_found;
1081 }
1082
1083 bool status_known(const basic_file_status &s) {
1084   return s.type() != file_type::status_error;
1085 }
1086
1087 file_type get_file_type(const Twine &Path, bool Follow) {
1088   file_status st;
1089   if (status(Path, st, Follow))
1090     return file_type::status_error;
1091   return st.type();
1092 }
1093
1094 bool is_directory(const basic_file_status &status) {
1095   return status.type() == file_type::directory_file;
1096 }
1097
1098 std::error_code is_directory(const Twine &path, bool &result) {
1099   file_status st;
1100   if (std::error_code ec = status(path, st))
1101     return ec;
1102   result = is_directory(st);
1103   return std::error_code();
1104 }
1105
1106 bool is_regular_file(const basic_file_status &status) {
1107   return status.type() == file_type::regular_file;
1108 }
1109
1110 std::error_code is_regular_file(const Twine &path, bool &result) {
1111   file_status st;
1112   if (std::error_code ec = status(path, st))
1113     return ec;
1114   result = is_regular_file(st);
1115   return std::error_code();
1116 }
1117
1118 bool is_symlink_file(const basic_file_status &status) {
1119   return status.type() == file_type::symlink_file;
1120 }
1121
1122 std::error_code is_symlink_file(const Twine &path, bool &result) {
1123   file_status st;
1124   if (std::error_code ec = status(path, st, false))
1125     return ec;
1126   result = is_symlink_file(st);
1127   return std::error_code();
1128 }
1129
1130 bool is_other(const basic_file_status &status) {
1131   return exists(status) &&
1132          !is_regular_file(status) &&
1133          !is_directory(status);
1134 }
1135
1136 std::error_code is_other(const Twine &Path, bool &Result) {
1137   file_status FileStatus;
1138   if (std::error_code EC = status(Path, FileStatus))
1139     return EC;
1140   Result = is_other(FileStatus);
1141   return std::error_code();
1142 }
1143
1144 void directory_entry::replace_filename(const Twine &Filename, file_type Type,
1145                                        basic_file_status Status) {
1146   SmallString<128> PathStr = path::parent_path(Path);
1147   path::append(PathStr, Filename);
1148   this->Path = std::string(PathStr);
1149   this->Type = Type;
1150   this->Status = Status;
1151 }
1152
1153 ErrorOr<perms> getPermissions(const Twine &Path) {
1154   file_status Status;
1155   if (std::error_code EC = status(Path, Status))
1156     return EC;
1157
1158   return Status.permissions();
1159 }
1160
1161 size_t mapped_file_region::size() const {
1162   assert(Mapping && "Mapping failed but used anyway!");
1163   return Size;
1164 }
1165
1166 char *mapped_file_region::data() const {
1167   assert(Mapping && "Mapping failed but used anyway!");
1168   return reinterpret_cast<char *>(Mapping);
1169 }
1170
1171 const char *mapped_file_region::const_data() const {
1172   assert(Mapping && "Mapping failed but used anyway!");
1173   return reinterpret_cast<const char *>(Mapping);
1174 }
1175
1176 Error readNativeFileToEOF(file_t FileHandle, SmallVectorImpl<char> &Buffer,
1177                           ssize_t ChunkSize) {
1178   // Install a handler to truncate the buffer to the correct size on exit.
1179   size_t Size = Buffer.size();
1180   auto TruncateOnExit = make_scope_exit([&]() { Buffer.truncate(Size); });
1181
1182   // Read into Buffer until we hit EOF.
1183   for (;;) {
1184     Buffer.resize_for_overwrite(Size + ChunkSize);
1185     Expected<size_t> ReadBytes = readNativeFile(
1186         FileHandle, MutableArrayRef(Buffer.begin() + Size, ChunkSize));
1187     if (!ReadBytes)
1188       return ReadBytes.takeError();
1189     if (*ReadBytes == 0)
1190       return Error::success();
1191     Size += *ReadBytes;
1192   }
1193 }
1194
1195 } // end namespace fs
1196 } // end namespace sys
1197 } // end namespace llvm
1198
1199 // Include the truly platform-specific parts.
1200 #if defined(LLVM_ON_UNIX)
1201 #include "Unix/Path.inc"
1202 #endif
1203 #if defined(_WIN32)
1204 #include "Windows/Path.inc"
1205 #endif
1206
1207 namespace llvm {
1208 namespace sys {
1209 namespace fs {
1210
1211 TempFile::TempFile(StringRef Name, int FD)
1212     : TmpName(std::string(Name)), FD(FD) {}
1213 TempFile::TempFile(TempFile &&Other) { *this = std::move(Other); }
1214 TempFile &TempFile::operator=(TempFile &&Other) {
1215   TmpName = std::move(Other.TmpName);
1216   FD = Other.FD;
1217   Other.Done = true;
1218   Other.FD = -1;
1219 #ifdef _WIN32
1220   RemoveOnClose = Other.RemoveOnClose;
1221   Other.RemoveOnClose = false;
1222 #endif
1223   return *this;
1224 }
1225
1226 TempFile::~TempFile() { assert(Done); }
1227
1228 Error TempFile::discard() {
1229   Done = true;
1230   if (FD != -1 && close(FD) == -1) {
1231     std::error_code EC = std::error_code(errno, std::generic_category());
1232     return errorCodeToError(EC);
1233   }
1234   FD = -1;
1235
1236 #ifdef _WIN32
1237   // On Windows, closing will remove the file, if we set the delete
1238   // disposition. If not, remove it manually.
1239   bool Remove = RemoveOnClose;
1240 #else
1241   // Always try to remove the file.
1242   bool Remove = true;
1243 #endif
1244   std::error_code RemoveEC;
1245   if (Remove && !TmpName.empty()) {
1246     RemoveEC = fs::remove(TmpName);
1247     sys::DontRemoveFileOnSignal(TmpName);
1248     if (!RemoveEC)
1249       TmpName = "";
1250   } else {
1251     TmpName = "";
1252   }
1253   return errorCodeToError(RemoveEC);
1254 }
1255
1256 Error TempFile::keep(const Twine &Name) {
1257   assert(!Done);
1258   Done = true;
1259   // Always try to close and rename.
1260 #ifdef _WIN32
1261   // If we can't cancel the delete don't rename.
1262   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1263   std::error_code RenameEC =
1264       RemoveOnClose ? std::error_code() : setDeleteDisposition(H, false);
1265   bool ShouldDelete = false;
1266   if (!RenameEC) {
1267     RenameEC = rename_handle(H, Name);
1268     // If rename failed because it's cross-device, copy instead
1269     if (RenameEC ==
1270       std::error_code(ERROR_NOT_SAME_DEVICE, std::system_category())) {
1271       RenameEC = copy_file(TmpName, Name);
1272       ShouldDelete = true;
1273     }
1274   }
1275
1276   // If we can't rename or copy, discard the temporary file.
1277   if (RenameEC)
1278     ShouldDelete = true;
1279   if (ShouldDelete) {
1280     if (!RemoveOnClose)
1281       setDeleteDisposition(H, true);
1282     else
1283       remove(TmpName);
1284   }
1285 #else
1286   std::error_code RenameEC = fs::rename(TmpName, Name);
1287   if (RenameEC) {
1288     // If we can't rename, try to copy to work around cross-device link issues.
1289     RenameEC = sys::fs::copy_file(TmpName, Name);
1290     // If we can't rename or copy, discard the temporary file.
1291     if (RenameEC)
1292       remove(TmpName);
1293   }
1294 #endif
1295   sys::DontRemoveFileOnSignal(TmpName);
1296
1297   if (!RenameEC)
1298     TmpName = "";
1299
1300   if (close(FD) == -1) {
1301     std::error_code EC(errno, std::generic_category());
1302     return errorCodeToError(EC);
1303   }
1304   FD = -1;
1305
1306   return errorCodeToError(RenameEC);
1307 }
1308
1309 Error TempFile::keep() {
1310   assert(!Done);
1311   Done = true;
1312
1313 #ifdef _WIN32
1314   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1315   if (std::error_code EC = setDeleteDisposition(H, false))
1316     return errorCodeToError(EC);
1317 #endif
1318   sys::DontRemoveFileOnSignal(TmpName);
1319
1320   TmpName = "";
1321
1322   if (close(FD) == -1) {
1323     std::error_code EC(errno, std::generic_category());
1324     return errorCodeToError(EC);
1325   }
1326   FD = -1;
1327
1328   return Error::success();
1329 }
1330
1331 Expected<TempFile> TempFile::create(const Twine &Model, unsigned Mode,
1332                                     OpenFlags ExtraFlags) {
1333   int FD;
1334   SmallString<128> ResultPath;
1335   if (std::error_code EC =
1336           createUniqueFile(Model, FD, ResultPath, OF_Delete | ExtraFlags, Mode))
1337     return errorCodeToError(EC);
1338
1339   TempFile Ret(ResultPath, FD);
1340 #ifdef _WIN32
1341   auto H = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
1342   bool SetSignalHandler = false;
1343   if (std::error_code EC = setDeleteDisposition(H, true)) {
1344     Ret.RemoveOnClose = true;
1345     SetSignalHandler = true;
1346   }
1347 #else
1348   bool SetSignalHandler = true;
1349 #endif
1350   if (SetSignalHandler && sys::RemoveFileOnSignal(ResultPath)) {
1351     // Make sure we delete the file when RemoveFileOnSignal fails.
1352     consumeError(Ret.discard());
1353     std::error_code EC(errc::operation_not_permitted);
1354     return errorCodeToError(EC);
1355   }
1356   return std::move(Ret);
1357 }
1358 } // namespace fs
1359
1360 } // namespace sys
1361 } // namespace llvm