/3rd_party/llvm/lib/Support/Path.cpp

   1//===-- Path.cpp - Implement OS Path Concept ------------------------------===//
   2//
   3//                     The LLVM Compiler Infrastructure
   4//
   5// This file is distributed under the University of Illinois Open Source
   6// License. See LICENSE.TXT for details.
   7//
   8//===----------------------------------------------------------------------===//
   9//
  10//  This file implements the operating system Path API.
  11//
  12//===----------------------------------------------------------------------===//
  13
  14#include "llvm/Support/Path.h"
  15#include "llvm/Support/Endian.h"
  16#include "llvm/Support/ErrorHandling.h"
  17#include "llvm/Support/FileSystem.h"
  18#include <cctype>
  19#include <cstdio>
  20#include <cstring>
  21#include <fcntl.h>
  22
  23#if !defined(_MSC_VER) && !defined(__MINGW32__)
  24#include <unistd.h>
  25#else
  26#include <io.h>
  27#endif
  28
  29namespace {
  30  using llvm::StringRef;
  31  using llvm::sys::path::is_separator;
  32
  33#ifdef LLVM_ON_WIN32
  34  const char *separators = "\\/";
  35  const char  prefered_separator = '\\';
  36#else
  37  const char  separators = '/';
  38  const char  prefered_separator = '/';
  39#endif
  40
  41  StringRef find_first_component(StringRef path) {
  42    // Look for this first component in the following order.
  43    // * empty (in this case we return an empty string)
  44    // * either C: or {//,\\}net.
  45    // * {/,\}
  46    // * {.,..}
  47    // * {file,directory}name
  48
  49    if (path.empty())
  50      return path;
  51
  52#ifdef LLVM_ON_WIN32
  53    // C:
  54    if (path.size() >= 2 && std::isalpha(static_cast<unsigned char>(path[0])) &&
  55        path[1] == ':')
  56      return path.substr(0, 2);
  57#endif
  58
  59    // //net
  60    if ((path.size() > 2) &&
  61        is_separator(path[0]) &&
  62        path[0] == path[1] &&
  63        !is_separator(path[2])) {
  64      // Find the next directory separator.
  65      size_t end = path.find_first_of(separators, 2);
  66      return path.substr(0, end);
  67    }
  68
  69    // {/,\}
  70    if (is_separator(path[0]))
  71      return path.substr(0, 1);
  72
  73    if (path.startswith(".."))
  74      return path.substr(0, 2);
  75
  76    if (path[0] == '.')
  77      return path.substr(0, 1);
  78
  79    // * {file,directory}name
  80    size_t end = path.find_first_of(separators);
  81    return path.substr(0, end);
  82  }
  83
  84  size_t filename_pos(StringRef str) {
  85    if (str.size() == 2 &&
  86        is_separator(str[0]) &&
  87        str[0] == str[1])
  88      return 0;
  89
  90    if (str.size() > 0 && is_separator(str[str.size() - 1]))
  91      return str.size() - 1;
  92
  93    size_t pos = str.find_last_of(separators, str.size() - 1);
  94
  95#ifdef LLVM_ON_WIN32
  96    if (pos == StringRef::npos)
  97      pos = str.find_last_of(':', str.size() - 2);
  98#endif
  99
 100    if (pos == StringRef::npos ||
 101        (pos == 1 && is_separator(str[0])))
 102      return 0;
 103
 104    return pos + 1;
 105  }
 106
 107  size_t root_dir_start(StringRef str) {
 108    // case "c:/"
 109#ifdef LLVM_ON_WIN32
 110    if (str.size() > 2 &&
 111        str[1] == ':' &&
 112        is_separator(str[2]))
 113      return 2;
 114#endif
 115
 116    // case "//"
 117    if (str.size() == 2 &&
 118        is_separator(str[0]) &&
 119        str[0] == str[1])
 120      return StringRef::npos;
 121
 122    // case "//net"
 123    if (str.size() > 3 &&
 124        is_separator(str[0]) &&
 125        str[0] == str[1] &&
 126        !is_separator(str[2])) {
 127      return str.find_first_of(separators, 2);
 128    }
 129
 130    // case "/"
 131    if (str.size() > 0 && is_separator(str[0]))
 132      return 0;
 133
 134    return StringRef::npos;
 135  }
 136
 137  size_t parent_path_end(StringRef path) {
 138    size_t end_pos = filename_pos(path);
 139
 140    bool filename_was_sep = path.size() > 0 && is_separator(path[end_pos]);
 141
 142    // Skip separators except for root dir.
 143    size_t root_dir_pos = root_dir_start(path.substr(0, end_pos));
 144
 145    while(end_pos > 0 &&
 146          (end_pos - 1) != root_dir_pos &&
 147          is_separator(path[end_pos - 1]))
 148      --end_pos;
 149
 150    if (end_pos == 1 && root_dir_pos == 0 && filename_was_sep)
 151      return StringRef::npos;
 152
 153    return end_pos;
 154  }
 155} // end unnamed namespace
 156
 157enum FSEntity {
 158  FS_Dir,
 159  FS_File,
 160  FS_Name
 161};
 162
 163// Implemented in Unix/Path.inc and Windows/Path.inc.
 164static llvm::error_code
 165createUniqueEntity(const llvm::Twine &Model, int &ResultFD,
 166                   llvm::SmallVectorImpl<char> &ResultPath,
 167                   bool MakeAbsolute, unsigned Mode, FSEntity Type);
 168
 169namespace llvm {
 170namespace sys  {
 171namespace path {
 172
 173const_iterator begin(StringRef path) {
 174  const_iterator i;
 175  i.Path      = path;
 176  i.Component = find_first_component(path);
 177  i.Position  = 0;
 178  return i;
 179}
 180
 181const_iterator end(StringRef path) {
 182  const_iterator i;
 183  i.Path      = path;
 184  i.Position  = path.size();
 185  return i;
 186}
 187
 188const_iterator &const_iterator::operator++() {
 189  assert(Position < Path.size() && "Tried to increment past end!");
 190
 191  // Increment Position to past the current component
 192  Position += Component.size();
 193
 194  // Check for end.
 195  if (Position == Path.size()) {
 196    Component = StringRef();
 197    return *this;
 198  }
 199
 200  // Both POSIX and Windows treat paths that begin with exactly two separators
 201  // specially.
 202  bool was_net = Component.size() > 2 &&
 203    is_separator(Component[0]) &&
 204    Component[1] == Component[0] &&
 205    !is_separator(Component[2]);
 206
 207  // Handle separators.
 208  if (is_separator(Path[Position])) {
 209    // Root dir.
 210    if (was_net
 211#ifdef LLVM_ON_WIN32
 212        // c:/
 213        || Component.endswith(":")
 214#endif
 215        ) {
 216      Component = Path.substr(Position, 1);
 217      return *this;
 218    }
 219
 220    // Skip extra separators.
 221    while (Position != Path.size() &&
 222           is_separator(Path[Position])) {
 223      ++Position;
 224    }
 225
 226    // Treat trailing '/' as a '.'.
 227    if (Position == Path.size()) {
 228      --Position;
 229      Component = ".";
 230      return *this;
 231    }
 232  }
 233
 234  // Find next component.
 235  size_t end_pos = Path.find_first_of(separators, Position);
 236  Component = Path.slice(Position, end_pos);
 237
 238  return *this;
 239}
 240
 241const_iterator &const_iterator::operator--() {
 242  // If we're at the end and the previous char was a '/', return '.'.
 243  if (Position == Path.size() &&
 244      Path.size() > 1 &&
 245      is_separator(Path[Position - 1])
 246#ifdef LLVM_ON_WIN32
 247      && Path[Position - 2] != ':'
 248#endif
 249      ) {
 250    --Position;
 251    Component = ".";
 252    return *this;
 253  }
 254
 255  // Skip separators unless it's the root directory.
 256  size_t root_dir_pos = root_dir_start(Path);
 257  size_t end_pos = Position;
 258
 259  while(end_pos > 0 &&
 260        (end_pos - 1) != root_dir_pos &&
 261        is_separator(Path[end_pos - 1]))
 262    --end_pos;
 263
 264  // Find next separator.
 265  size_t start_pos = filename_pos(Path.substr(0, end_pos));
 266  Component = Path.slice(start_pos, end_pos);
 267  Position = start_pos;
 268  return *this;
 269}
 270
 271bool const_iterator::operator==(const const_iterator &RHS) const {
 272  return Path.begin() == RHS.Path.begin() &&
 273         Position == RHS.Position;
 274}
 275
 276bool const_iterator::operator!=(const const_iterator &RHS) const {
 277  return !(*this == RHS);
 278}
 279
 280ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
 281  return Position - RHS.Position;
 282}
 283
 284const StringRef root_path(StringRef path) {
 285  const_iterator b = begin(path),
 286                 pos = b,
 287                 e = end(path);
 288  if (b != e) {
 289    bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
 290    bool has_drive =
 291#ifdef LLVM_ON_WIN32
 292      b->endswith(":");
 293#else
 294      false;
 295#endif
 296
 297    if (has_net || has_drive) {
 298      if ((++pos != e) && is_separator((*pos)[0])) {
 299        // {C:/,//net/}, so get the first two components.
 300        return path.substr(0, b->size() + pos->size());
 301      } else {
 302        // just {C:,//net}, return the first component.
 303        return *b;
 304      }
 305    }
 306
 307    // POSIX style root directory.
 308    if (is_separator((*b)[0])) {
 309      return *b;
 310    }
 311  }
 312
 313  return StringRef();
 314}
 315
 316const StringRef root_name(StringRef path) {
 317  const_iterator b = begin(path),
 318                 e = end(path);
 319  if (b != e) {
 320    bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
 321    bool has_drive =
 322#ifdef LLVM_ON_WIN32
 323      b->endswith(":");
 324#else
 325      false;
 326#endif
 327
 328    if (has_net || has_drive) {
 329      // just {C:,//net}, return the first component.
 330      return *b;
 331    }
 332  }
 333
 334  // No path or no name.
 335  return StringRef();
 336}
 337
 338const StringRef root_directory(StringRef path) {
 339  const_iterator b = begin(path),
 340                 pos = b,
 341                 e = end(path);
 342  if (b != e) {
 343    bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
 344    bool has_drive =
 345#ifdef LLVM_ON_WIN32
 346      b->endswith(":");
 347#else
 348      false;
 349#endif
 350
 351    if ((has_net || has_drive) &&
 352        // {C:,//net}, skip to the next component.
 353        (++pos != e) && is_separator((*pos)[0])) {
 354      return *pos;
 355    }
 356
 357    // POSIX style root directory.
 358    if (!has_net && is_separator((*b)[0])) {
 359      return *b;
 360    }
 361  }
 362
 363  // No path or no root.
 364  return StringRef();
 365}
 366
 367const StringRef relative_path(StringRef path) {
 368  StringRef root = root_path(path);
 369  return path.substr(root.size());
 370}
 371
 372void append(SmallVectorImpl<char> &path, const Twine &a,
 373                                         const Twine &b,
 374                                         const Twine &c,
 375                                         const Twine &d) {
 376  SmallString<32> a_storage;
 377  SmallString<32> b_storage;
 378  SmallString<32> c_storage;
 379  SmallString<32> d_storage;
 380
 381  SmallVector<StringRef, 4> components;
 382  if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
 383  if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
 384  if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
 385  if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
 386
 387  for (SmallVectorImpl<StringRef>::const_iterator i = components.begin(),
 388                                                  e = components.end();
 389                                                  i != e; ++i) {
 390    bool path_has_sep = !path.empty() && is_separator(path[path.size() - 1]);
 391    bool component_has_sep = !i->empty() && is_separator((*i)[0]);
 392    bool is_root_name = has_root_name(*i);
 393
 394    if (path_has_sep) {
 395      // Strip separators from beginning of component.
 396      size_t loc = i->find_first_not_of(separators);
 397      StringRef c = i->substr(loc);
 398
 399      // Append it.
 400      path.append(c.begin(), c.end());
 401      continue;
 402    }
 403
 404    if (!component_has_sep && !(path.empty() || is_root_name)) {
 405      // Add a separator.
 406      path.push_back(prefered_separator);
 407    }
 408
 409    path.append(i->begin(), i->end());
 410  }
 411}
 412
 413void append(SmallVectorImpl<char> &path,
 414            const_iterator begin, const_iterator end) {
 415  for (; begin != end; ++begin)
 416    path::append(path, *begin);
 417}
 418
 419const StringRef parent_path(StringRef path) {
 420  size_t end_pos = parent_path_end(path);
 421  if (end_pos == StringRef::npos)
 422    return StringRef();
 423  else
 424    return path.substr(0, end_pos);
 425}
 426
 427void remove_filename(SmallVectorImpl<char> &path) {
 428  size_t end_pos = parent_path_end(StringRef(path.begin(), path.size()));
 429  if (end_pos != StringRef::npos)
 430    path.set_size(end_pos);
 431}
 432
 433void replace_extension(SmallVectorImpl<char> &path, const Twine &extension) {
 434  StringRef p(path.begin(), path.size());
 435  SmallString<32> ext_storage;
 436  StringRef ext = extension.toStringRef(ext_storage);
 437
 438  // Erase existing extension.
 439  size_t pos = p.find_last_of('.');
 440  if (pos != StringRef::npos && pos >= filename_pos(p))
 441    path.set_size(pos);
 442
 443  // Append '.' if needed.
 444  if (ext.size() > 0 && ext[0] != '.')
 445    path.push_back('.');
 446
 447  // Append extension.
 448  path.append(ext.begin(), ext.end());
 449}
 450
 451void native(const Twine &path, SmallVectorImpl<char> &result) {
 452  assert((!path.isSingleStringRef() ||
 453          path.getSingleStringRef().data() != result.data()) &&
 454         "path and result are not allowed to overlap!");
 455  // Clear result.
 456  result.clear();
 457  path.toVector(result);
 458  native(result);
 459}
 460
 461void native(SmallVectorImpl<char> &path) {
 462#ifdef LLVM_ON_WIN32
 463  std::replace(path.begin(), path.end(), '/', '\\');
 464#endif
 465}
 466
 467const StringRef filename(StringRef path) {
 468  return *(--end(path));
 469}
 470
 471const StringRef stem(StringRef path) {
 472  StringRef fname = filename(path);
 473  size_t pos = fname.find_last_of('.');
 474  if (pos == StringRef::npos)
 475    return fname;
 476  else
 477    if ((fname.size() == 1 && fname == ".") ||
 478        (fname.size() == 2 && fname == ".."))
 479      return fname;
 480    else
 481      return fname.substr(0, pos);
 482}
 483
 484const StringRef extension(StringRef path) {
 485  StringRef fname = filename(path);
 486  size_t pos = fname.find_last_of('.');
 487  if (pos == StringRef::npos)
 488    return StringRef();
 489  else
 490    if ((fname.size() == 1 && fname == ".") ||
 491        (fname.size() == 2 && fname == ".."))
 492      return StringRef();
 493    else
 494      return fname.substr(pos);
 495}
 496
 497bool is_separator(char value) {
 498  switch(value) {
 499#ifdef LLVM_ON_WIN32
 500    case '\\': // fall through
 501#endif
 502    case '/': return true;
 503    default: return false;
 504  }
 505}
 506
 507void system_temp_directory(bool erasedOnReboot, SmallVectorImpl<char> &result) {
 508  result.clear();
 509
 510#ifdef __APPLE__
 511  // On Darwin, use DARWIN_USER_TEMP_DIR or DARWIN_USER_CACHE_DIR.
 512  int ConfName = erasedOnReboot? _CS_DARWIN_USER_TEMP_DIR
 513                               : _CS_DARWIN_USER_CACHE_DIR;
 514  size_t ConfLen = confstr(ConfName, 0, 0);
 515  if (ConfLen > 0) {
 516    do {
 517      result.resize(ConfLen);
 518      ConfLen = confstr(ConfName, result.data(), result.size());
 519    } while (ConfLen > 0 && ConfLen != result.size());
 520
 521    if (ConfLen > 0) {
 522      assert(result.back() == 0);
 523      result.pop_back();
 524      return;
 525    }
 526
 527    result.clear();
 528  }
 529#endif
 530
 531  // Check whether the temporary directory is specified by an environment
 532  // variable.
 533  const char *EnvironmentVariable;
 534#ifdef LLVM_ON_WIN32
 535  EnvironmentVariable = "TEMP";
 536#else
 537  EnvironmentVariable = "TMPDIR";
 538#endif
 539  if (char *RequestedDir = getenv(EnvironmentVariable)) {
 540    result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
 541    return;
 542  }
 543
 544  // Fall back to a system default.
 545  const char *DefaultResult;
 546#ifdef LLVM_ON_WIN32
 547  (void)erasedOnReboot;
 548  DefaultResult = "C:\\TEMP";
 549#else
 550  if (erasedOnReboot)
 551    DefaultResult = "/tmp";
 552  else
 553    DefaultResult = "/var/tmp";
 554#endif
 555  result.append(DefaultResult, DefaultResult + strlen(DefaultResult));
 556}
 557
 558bool has_root_name(const Twine &path) {
 559  SmallString<128> path_storage;
 560  StringRef p = path.toStringRef(path_storage);
 561
 562  return !root_name(p).empty();
 563}
 564
 565bool has_root_directory(const Twine &path) {
 566  SmallString<128> path_storage;
 567  StringRef p = path.toStringRef(path_storage);
 568
 569  return !root_directory(p).empty();
 570}
 571
 572bool has_root_path(const Twine &path) {
 573  SmallString<128> path_storage;
 574  StringRef p = path.toStringRef(path_storage);
 575
 576  return !root_path(p).empty();
 577}
 578
 579bool has_relative_path(const Twine &path) {
 580  SmallString<128> path_storage;
 581  StringRef p = path.toStringRef(path_storage);
 582
 583  return !relative_path(p).empty();
 584}
 585
 586bool has_filename(const Twine &path) {
 587  SmallString<128> path_storage;
 588  StringRef p = path.toStringRef(path_storage);
 589
 590  return !filename(p).empty();
 591}
 592
 593bool has_parent_path(const Twine &path) {
 594  SmallString<128> path_storage;
 595  StringRef p = path.toStringRef(path_storage);
 596
 597  return !parent_path(p).empty();
 598}
 599
 600bool has_stem(const Twine &path) {
 601  SmallString<128> path_storage;
 602  StringRef p = path.toStringRef(path_storage);
 603
 604  return !stem(p).empty();
 605}
 606
 607bool has_extension(const Twine &path) {
 608  SmallString<128> path_storage;
 609  StringRef p = path.toStringRef(path_storage);
 610
 611  return !extension(p).empty();
 612}
 613
 614bool is_absolute(const Twine &path) {
 615  SmallString<128> path_storage;
 616  StringRef p = path.toStringRef(path_storage);
 617
 618  bool rootDir = has_root_directory(p),
 619#ifdef LLVM_ON_WIN32
 620       rootName = has_root_name(p);
 621#else
 622       rootName = true;
 623#endif
 624
 625  return rootDir && rootName;
 626}
 627
 628bool is_relative(const Twine &path) {
 629  return !is_absolute(path);
 630}
 631
 632} // end namespace path
 633
 634namespace fs {
 635
 636error_code getUniqueID(const Twine Path, UniqueID &Result) {
 637  file_status Status;
 638  error_code EC = status(Path, Status);
 639  if (EC)
 640    return EC;
 641  Result = Status.getUniqueID();
 642  return error_code::success();
 643}
 644
 645error_code createUniqueFile(const Twine &Model, int &ResultFd,
 646                            SmallVectorImpl<char> &ResultPath, unsigned Mode) {
 647  return createUniqueEntity(Model, ResultFd, ResultPath, false, Mode, FS_File);
 648}
 649
 650error_code createUniqueFile(const Twine &Model,
 651                            SmallVectorImpl<char> &ResultPath) {
 652  int Dummy;
 653  return createUniqueEntity(Model, Dummy, ResultPath, false, 0, FS_Name);
 654}
 655
 656static error_code createTemporaryFile(const Twine &Model, int &ResultFD,
 657                                      llvm::SmallVectorImpl<char> &ResultPath,
 658                                      FSEntity Type) {
 659  SmallString<128> Storage;
 660  StringRef P = Model.toNullTerminatedStringRef(Storage);
 661  assert(P.find_first_of(separators) == StringRef::npos &&
 662         "Model must be a simple filename.");
 663  // Use P.begin() so that createUniqueEntity doesn't need to recreate Storage.
 664  return createUniqueEntity(P.begin(), ResultFD, ResultPath,
 665                            true, owner_read | owner_write, Type);
 666}
 667
 668static error_code
 669createTemporaryFile(const Twine &Prefix, StringRef Suffix, int &ResultFD,
 670                    llvm::SmallVectorImpl<char> &ResultPath,
 671                    FSEntity Type) {
 672  const char *Middle = Suffix.empty() ? "-%%%%%%" : "-%%%%%%.";
 673  return createTemporaryFile(Prefix + Middle + Suffix, ResultFD, ResultPath,
 674                             Type);
 675}
 676
 677
 678error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 679                               int &ResultFD,
 680                               SmallVectorImpl<char> &ResultPath) {
 681  return createTemporaryFile(Prefix, Suffix, ResultFD, ResultPath, FS_File);
 682}
 683
 684error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
 685                               SmallVectorImpl<char> &ResultPath) {
 686  int Dummy;
 687  return createTemporaryFile(Prefix, Suffix, Dummy, ResultPath, FS_Name);
 688}
 689
 690
 691// This is a mkdtemp with a different pattern. We use createUniqueEntity mostly
 692// for consistency. We should try using mkdtemp.
 693error_code createUniqueDirectory(const Twine &Prefix,
 694                                 SmallVectorImpl<char> &ResultPath) {
 695  int Dummy;
 696  return createUniqueEntity(Prefix + "-%%%%%%", Dummy, ResultPath,
 697                            true, 0, FS_Dir);
 698}
 699
 700error_code make_absolute(SmallVectorImpl<char> &path) {
 701  StringRef p(path.data(), path.size());
 702
 703  bool rootDirectory = path::has_root_directory(p),
 704#ifdef LLVM_ON_WIN32
 705       rootName = path::has_root_name(p);
 706#else
 707       rootName = true;
 708#endif
 709
 710  // Already absolute.
 711  if (rootName && rootDirectory)
 712    return error_code::success();
 713
 714  // All of the following conditions will need the current directory.
 715  SmallString<128> current_dir;
 716  if (error_code ec = current_path(current_dir)) return ec;
 717
 718  // Relative path. Prepend the current directory.
 719  if (!rootName && !rootDirectory) {
 720    // Append path to the current directory.
 721    path::append(current_dir, p);
 722    // Set path to the result.
 723    path.swap(current_dir);
 724    return error_code::success();
 725  }
 726
 727  if (!rootName && rootDirectory) {
 728    StringRef cdrn = path::root_name(current_dir);
 729    SmallString<128> curDirRootName(cdrn.begin(), cdrn.end());
 730    path::append(curDirRootName, p);
 731    // Set path to the result.
 732    path.swap(curDirRootName);
 733    return error_code::success();
 734  }
 735
 736  if (rootName && !rootDirectory) {
 737    StringRef pRootName      = path::root_name(p);
 738    StringRef bRootDirectory = path::root_directory(current_dir);
 739    StringRef bRelativePath  = path::relative_path(current_dir);
 740    StringRef pRelativePath  = path::relative_path(p);
 741
 742    SmallString<128> res;
 743    path::append(res, pRootName, bRootDirectory, bRelativePath, pRelativePath);
 744    path.swap(res);
 745    return error_code::success();
 746  }
 747
 748  llvm_unreachable("All rootName and rootDirectory combinations should have "
 749                   "occurred above!");
 750}
 751
 752error_code create_directories(const Twine &path, bool &existed) {
 753  SmallString<128> path_storage;
 754  StringRef p = path.toStringRef(path_storage);
 755
 756  StringRef parent = path::parent_path(p);
 757  if (!parent.empty()) {
 758    bool parent_exists;
 759    if (error_code ec = fs::exists(parent, parent_exists)) return ec;
 760
 761    if (!parent_exists)
 762      if (error_code ec = create_directories(parent, existed)) return ec;
 763  }
 764
 765  return create_directory(p, existed);
 766}
 767
 768bool exists(file_status status) {
 769  return status_known(status) && status.type() != file_type::file_not_found;
 770}
 771
 772bool status_known(file_status s) {
 773  return s.type() != file_type::status_error;
 774}
 775
 776bool is_directory(file_status status) {
 777  return status.type() == file_type::directory_file;
 778}
 779
 780error_code is_directory(const Twine &path, bool &result) {
 781  file_status st;
 782  if (error_code ec = status(path, st))
 783    return ec;
 784  result = is_directory(st);
 785  return error_code::success();
 786}
 787
 788bool is_regular_file(file_status status) {
 789  return status.type() == file_type::regular_file;
 790}
 791
 792error_code is_regular_file(const Twine &path, bool &result) {
 793  file_status st;
 794  if (error_code ec = status(path, st))
 795    return ec;
 796  result = is_regular_file(st);
 797  return error_code::success();
 798}
 799
 800bool is_symlink(file_status status) {
 801  return status.type() == file_type::symlink_file;
 802}
 803
 804error_code is_symlink(const Twine &path, bool &result) {
 805  file_status st;
 806  if (error_code ec = status(path, st))
 807    return ec;
 808  result = is_symlink(st);
 809  return error_code::success();
 810}
 811
 812bool is_other(file_status status) {
 813  return exists(status) &&
 814         !is_regular_file(status) &&
 815         !is_directory(status) &&
 816         !is_symlink(status);
 817}
 818
 819void directory_entry::replace_filename(const Twine &filename, file_status st) {
 820  SmallString<128> path(Path.begin(), Path.end());
 821  path::remove_filename(path);
 822  path::append(path, filename);
 823  Path = path.str();
 824  Status = st;
 825}
 826
 827error_code has_magic(const Twine &path, const Twine &magic, bool &result) {
 828  SmallString<32>  MagicStorage;
 829  StringRef Magic = magic.toStringRef(MagicStorage);
 830  SmallString<32> Buffer;
 831
 832  if (error_code ec = get_magic(path, Magic.size(), Buffer)) {
 833    if (ec == errc::value_too_large) {
 834      // Magic.size() > file_size(Path).
 835      result = false;
 836      return error_code::success();
 837    }
 838    return ec;
 839  }
 840
 841  result = Magic == Buffer;
 842  return error_code::success();
 843}
 844
 845/// @brief Identify the magic in magic.
 846  file_magic identify_magic(StringRef Magic) {
 847  if (Magic.size() < 4)
 848    return file_magic::unknown;
 849  switch ((unsigned char)Magic[0]) {
 850    case 0x00: {
 851      // COFF short import library file
 852      if (Magic[1] == (char)0x00 && Magic[2] == (char)0xff &&
 853          Magic[3] == (char)0xff)
 854        return file_magic::coff_import_library;
 855      // Windows resource file
 856      const char Expected[] = { 0, 0, 0, 0, '\x20', 0, 0, 0, '\xff' };
 857      if (Magic.size() >= sizeof(Expected) &&
 858          memcmp(Magic.data(), Expected, sizeof(Expected)) == 0)
 859        return file_magic::windows_resource;
 860      // 0x0000 = COFF unknown machine type
 861      if (Magic[1] == 0)
 862        return file_magic::coff_object;
 863      break;
 864    }
 865    case 0xDE:  // 0x0B17C0DE = BC wraper
 866      if (Magic[1] == (char)0xC0 && Magic[2] == (char)0x17 &&
 867          Magic[3] == (char)0x0B)
 868        return file_magic::bitcode;
 869      break;
 870    case 'B':
 871      if (Magic[1] == 'C' && Magic[2] == (char)0xC0 && Magic[3] == (char)0xDE)
 872        return file_magic::bitcode;
 873      break;
 874    case '!':
 875      if (Magic.size() >= 8)
 876        if (memcmp(Magic.data(),"!<arch>\n",8) == 0)
 877          return file_magic::archive;
 878      break;
 879
 880    case '\177':
 881      if (Magic.size() >= 18 && Magic[1] == 'E' && Magic[2] == 'L' &&
 882          Magic[3] == 'F') {
 883        bool Data2MSB = Magic[5] == 2;
 884        unsigned high = Data2MSB ? 16 : 17;
 885        unsigned low  = Data2MSB ? 17 : 16;
 886        if (Magic[high] == 0)
 887          switch (Magic[low]) {
 888            default: break;
 889            case 1: return file_magic::elf_relocatable;
 890            case 2: return file_magic::elf_executable;
 891            case 3: return file_magic::elf_shared_object;
 892            case 4: return file_magic::elf_core;
 893          }
 894      }
 895      break;
 896
 897    case 0xCA:
 898      if (Magic[1] == char(0xFE) && Magic[2] == char(0xBA) &&
 899          Magic[3] == char(0xBE)) {
 900        // This is complicated by an overlap with Java class files.
 901        // See the Mach-O section in /usr/share/file/magic for details.
 902        if (Magic.size() >= 8 && Magic[7] < 43)
 903          return file_magic::macho_universal_binary;
 904      }
 905      break;
 906
 907      // The two magic numbers for mach-o are:
 908      // 0xfeedface - 32-bit mach-o
 909      // 0xfeedfacf - 64-bit mach-o
 910    case 0xFE:
 911    case 0xCE:
 912    case 0xCF: {
 913      uint16_t type = 0;
 914      if (Magic[0] == char(0xFE) && Magic[1] == char(0xED) &&
 915          Magic[2] == char(0xFA) &&
 916          (Magic[3] == char(0xCE) || Magic[3] == char(0xCF))) {
 917        /* Native endian */
 918        if (Magic.size() >= 16) type = Magic[14] << 8 | Magic[15];
 919      } else if ((Magic[0] == char(0xCE) || Magic[0] == char(0xCF)) &&
 920                 Magic[1] == char(0xFA) && Magic[2] == char(0xED) &&
 921                 Magic[3] == char(0xFE)) {
 922        /* Reverse endian */
 923        if (Magic.size() >= 14) type = Magic[13] << 8 | Magic[12];
 924      }
 925      switch (type) {
 926        default: break;
 927        case 1: return file_magic::macho_object;
 928        case 2: return file_magic::macho_executable;
 929        case 3: return file_magic::macho_fixed_virtual_memory_shared_lib;
 930        case 4: return file_magic::macho_core;
 931        case 5: return file_magic::macho_preload_executable;
 932        case 6: return file_magic::macho_dynamically_linked_shared_lib;
 933        case 7: return file_magic::macho_dynamic_linker;
 934        case 8: return file_magic::macho_bundle;
 935        case 9: return file_magic::macho_dynamic_linker;
 936        case 10: return file_magic::macho_dsym_companion;
 937      }
 938      break;
 939    }
 940    case 0xF0: // PowerPC Windows
 941    case 0x83: // Alpha 32-bit
 942    case 0x84: // Alpha 64-bit
 943    case 0x66: // MPS R4000 Windows
 944    case 0x50: // mc68K
 945    case 0x4c: // 80386 Windows
 946      if (Magic[1] == 0x01)
 947        return file_magic::coff_object;
 948
 949    case 0x90: // PA-RISC Windows
 950    case 0x68: // mc68K Windows
 951      if (Magic[1] == 0x02)
 952        return file_magic::coff_object;
 953      break;
 954
 955    case 0x4d: // Possible MS-DOS stub on Windows PE file
 956      if (Magic[1] == 0x5a) {
 957        uint32_t off =
 958          *reinterpret_cast<const support::ulittle32_t*>(Magic.data() + 0x3c);
 959        // PE/COFF file, either EXE or DLL.
 960        if (off < Magic.size() && memcmp(Magic.data() + off, "PE\0\0",4) == 0)
 961          return file_magic::pecoff_executable;
 962      }
 963      break;
 964
 965    case 0x64: // x86-64 Windows.
 966      if (Magic[1] == char(0x86))
 967        return file_magic::coff_object;
 968      break;
 969
 970    default:
 971      break;
 972  }
 973  return file_magic::unknown;
 974}
 975
 976error_code identify_magic(const Twine &path, file_magic &result) {
 977  SmallString<32> Magic;
 978  error_code ec = get_magic(path, Magic.capacity(), Magic);
 979  if (ec && ec != errc::value_too_large)
 980    return ec;
 981
 982  result = identify_magic(Magic);
 983  return error_code::success();
 984}
 985
 986namespace {
 987error_code remove_all_r(StringRef path, file_type ft, uint32_t &count) {
 988  if (ft == file_type::directory_file) {
 989    // This code would be a lot better with exceptions ;/.
 990    error_code ec;
 991    directory_iterator i(path, ec);
 992    if (ec) return ec;
 993    for (directory_iterator e; i != e; i.increment(ec)) {
 994      if (ec) return ec;
 995      file_status st;
 996      if (error_code ec = i->status(st)) return ec;
 997      if (error_code ec = remove_all_r(i->path(), st.type(), count)) return ec;
 998    }
 999    bool obviously_this_exists;
1000    if (error_code ec = remove(path, obviously_this_exists)) return ec;
1001    assert(obviously_this_exists);
1002    ++count; // Include the directory itself in the items removed.
1003  } else {
1004    bool obviously_this_exists;
1005    if (error_code ec = remove(path, obviously_this_exists)) return ec;
1006    assert(obviously_this_exists);
1007    ++count;
1008  }
1009
1010  return error_code::success();
1011}
1012} // end unnamed namespace
1013
1014error_code remove_all(const Twine &path, uint32_t &num_removed) {
1015  SmallString<128> path_storage;
1016  StringRef p = path.toStringRef(path_storage);
1017
1018  file_status fs;
1019  if (error_code ec = status(path, fs))
1020    return ec;
1021  num_removed = 0;
1022  return remove_all_r(p, fs.type(), num_removed);
1023}
1024
1025error_code directory_entry::status(file_status &result) const {
1026  return fs::status(Path, result);
1027}
1028
1029} // end namespace fs
1030} // end namespace sys
1031} // end namespace llvm
1032
1033// Include the truly platform-specific parts.
1034#if defined(LLVM_ON_UNIX)
1035#include "Unix/Path.inc"
1036#endif
1037#if defined(LLVM_ON_WIN32)
1038#include "Windows/Path.inc"
1039#endif