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