PathV2.inc revision d45fbe62270eaf826419b93f1da66f1850f37faf 
1//===- llvm/Support/Windows/PathV2.inc - Windows Path Impl ------*- C++ -*-===//
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 Windows specific implementation of the PathV2 API.
11//
12//===----------------------------------------------------------------------===//
13
14//===----------------------------------------------------------------------===//
15//=== WARNING: Implementation here must contain only generic Windows code that
16//===          is guaranteed to work on *all* Windows variants.
17//===----------------------------------------------------------------------===//
18
19#include "Windows.h"
20#include <fcntl.h>
21#include <io.h>
22#include <sys/stat.h>
23#include <sys/types.h>
24
25// MinGW doesn't define this.
26#ifndef _ERRNO_T_DEFINED
27#define _ERRNO_T_DEFINED
28typedef int errno_t;
29#endif
30
31using namespace llvm;
32
33namespace {
34  typedef BOOLEAN (WINAPI *PtrCreateSymbolicLinkW)(
35    /*__in*/ LPCWSTR lpSymlinkFileName,
36    /*__in*/ LPCWSTR lpTargetFileName,
37    /*__in*/ DWORD dwFlags);
38
39  PtrCreateSymbolicLinkW create_symbolic_link_api = PtrCreateSymbolicLinkW(
40    ::GetProcAddress(::GetModuleHandleA("kernel32.dll"),
41                     "CreateSymbolicLinkW"));
42
43  error_code UTF8ToUTF16(StringRef utf8, SmallVectorImpl<wchar_t> &utf16) {
44    int len = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS,
45                                    utf8.begin(), utf8.size(),
46                                    utf16.begin(), 0);
47
48    if (len == 0)
49      return windows_error(::GetLastError());
50
51    utf16.reserve(len + 1);
52    utf16.set_size(len);
53
54    len = ::MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS,
55                                    utf8.begin(), utf8.size(),
56                                    utf16.begin(), utf16.size());
57
58    if (len == 0)
59      return windows_error(::GetLastError());
60
61    // Make utf16 null terminated.
62    utf16.push_back(0);
63    utf16.pop_back();
64
65    return success;
66  }
67
68  error_code UTF16ToUTF8(const wchar_t *utf16, size_t utf16_len,
69                               SmallVectorImpl<char> &utf8) {
70    // Get length.
71    int len = ::WideCharToMultiByte(CP_UTF8, 0,
72                                    utf16, utf16_len,
73                                    utf8.begin(), 0,
74                                    NULL, NULL);
75
76    if (len == 0)
77      return windows_error(::GetLastError());
78
79    utf8.reserve(len);
80    utf8.set_size(len);
81
82    // Now do the actual conversion.
83    len = ::WideCharToMultiByte(CP_UTF8, 0,
84                                utf16, utf16_len,
85                                utf8.data(), utf8.size(),
86                                NULL, NULL);
87
88    if (len == 0)
89      return windows_error(::GetLastError());
90
91    // Make utf8 null terminated.
92    utf8.push_back(0);
93    utf8.pop_back();
94
95    return success;
96  }
97
98  error_code TempDir(SmallVectorImpl<wchar_t> &result) {
99  retry_temp_dir:
100    DWORD len = ::GetTempPathW(result.capacity(), result.begin());
101
102    if (len == 0)
103      return windows_error(::GetLastError());
104
105    if (len > result.capacity()) {
106      result.reserve(len);
107      goto retry_temp_dir;
108    }
109
110    result.set_size(len);
111    return success;
112  }
113
114  bool is_separator(const wchar_t value) {
115    switch (value) {
116    case L'\\':
117    case L'/':
118      return true;
119    default:
120      return false;
121    }
122  }
123}
124
125namespace llvm {
126namespace sys  {
127namespace fs {
128
129error_code current_path(SmallVectorImpl<char> &result) {
130  SmallVector<wchar_t, 128> cur_path;
131  cur_path.reserve(128);
132retry_cur_dir:
133  DWORD len = ::GetCurrentDirectoryW(cur_path.capacity(), cur_path.data());
134
135  // A zero return value indicates a failure other than insufficient space.
136  if (len == 0)
137    return windows_error(::GetLastError());
138
139  // If there's insufficient space, the len returned is larger than the len
140  // given.
141  if (len > cur_path.capacity()) {
142    cur_path.reserve(len);
143    goto retry_cur_dir;
144  }
145
146  cur_path.set_size(len);
147  // cur_path now holds the current directory in utf-16. Convert to utf-8.
148
149  // Find out how much space we need. Sadly, this function doesn't return the
150  // size needed unless you tell it the result size is 0, which means you
151  // _always_ have to call it twice.
152  len = ::WideCharToMultiByte(CP_UTF8, 0,
153                              cur_path.data(), cur_path.size(),
154                              result.data(), 0,
155                              NULL, NULL);
156
157  if (len == 0)
158    return make_error_code(windows_error(::GetLastError()));
159
160  result.reserve(len);
161  result.set_size(len);
162  // Now do the actual conversion.
163  len = ::WideCharToMultiByte(CP_UTF8, 0,
164                              cur_path.data(), cur_path.size(),
165                              result.data(), result.size(),
166                              NULL, NULL);
167  if (len == 0)
168    return windows_error(::GetLastError());
169
170  return success;
171}
172
173error_code copy_file(const Twine &from, const Twine &to, copy_option copt) {
174  // Get arguments.
175  SmallString<128> from_storage;
176  SmallString<128> to_storage;
177  StringRef f = from.toStringRef(from_storage);
178  StringRef t = to.toStringRef(to_storage);
179
180  // Convert to utf-16.
181  SmallVector<wchar_t, 128> wide_from;
182  SmallVector<wchar_t, 128> wide_to;
183  if (error_code ec = UTF8ToUTF16(f, wide_from)) return ec;
184  if (error_code ec = UTF8ToUTF16(t, wide_to)) return ec;
185
186  // Copy the file.
187  BOOL res = ::CopyFileW(wide_from.begin(), wide_to.begin(),
188                         copt != copy_option::overwrite_if_exists);
189
190  if (res == 0)
191    return windows_error(::GetLastError());
192
193  return success;
194}
195
196error_code create_directory(const Twine &path, bool &existed) {
197  SmallString<128> path_storage;
198  SmallVector<wchar_t, 128> path_utf16;
199
200  if (error_code ec = UTF8ToUTF16(path.toStringRef(path_storage),
201                                  path_utf16))
202    return ec;
203
204  if (!::CreateDirectoryW(path_utf16.begin(), NULL)) {
205    error_code ec = windows_error(::GetLastError());
206    if (ec == windows_error::already_exists)
207      existed = true;
208    else
209      return ec;
210  } else
211    existed = false;
212
213  return success;
214}
215
216error_code create_hard_link(const Twine &to, const Twine &from) {
217  // Get arguments.
218  SmallString<128> from_storage;
219  SmallString<128> to_storage;
220  StringRef f = from.toStringRef(from_storage);
221  StringRef t = to.toStringRef(to_storage);
222
223  // Convert to utf-16.
224  SmallVector<wchar_t, 128> wide_from;
225  SmallVector<wchar_t, 128> wide_to;
226  if (error_code ec = UTF8ToUTF16(f, wide_from)) return ec;
227  if (error_code ec = UTF8ToUTF16(t, wide_to)) return ec;
228
229  if (!::CreateHardLinkW(wide_from.begin(), wide_to.begin(), NULL))
230    return windows_error(::GetLastError());
231
232  return success;
233}
234
235error_code create_symlink(const Twine &to, const Twine &from) {
236  // Only do it if the function is available at runtime.
237  if (!create_symbolic_link_api)
238    return make_error_code(errc::function_not_supported);
239
240  // Get arguments.
241  SmallString<128> from_storage;
242  SmallString<128> to_storage;
243  StringRef f = from.toStringRef(from_storage);
244  StringRef t = to.toStringRef(to_storage);
245
246  // Convert to utf-16.
247  SmallVector<wchar_t, 128> wide_from;
248  SmallVector<wchar_t, 128> wide_to;
249  if (error_code ec = UTF8ToUTF16(f, wide_from)) return ec;
250  if (error_code ec = UTF8ToUTF16(t, wide_to)) return ec;
251
252  if (!create_symbolic_link_api(wide_from.begin(), wide_to.begin(), 0))
253    return windows_error(::GetLastError());
254
255  return success;
256}
257
258error_code remove(const Twine &path, bool &existed) {
259  SmallString<128> path_storage;
260  SmallVector<wchar_t, 128> path_utf16;
261
262  file_status st;
263  if (error_code ec = status(path, st))
264    return ec;
265
266  if (error_code ec = UTF8ToUTF16(path.toStringRef(path_storage),
267                                  path_utf16))
268    return ec;
269
270  if (st.type() == file_type::directory_file) {
271    if (!::RemoveDirectoryW(c_str(path_utf16))) {
272      error_code ec = windows_error(::GetLastError());
273      if (ec != windows_error::file_not_found)
274        return ec;
275      existed = false;
276    } else
277      existed = true;
278  } else {
279    if (!::DeleteFileW(c_str(path_utf16))) {
280      error_code ec = windows_error(::GetLastError());
281      if (ec != windows_error::file_not_found)
282        return ec;
283      existed = false;
284    } else
285      existed = true;
286  }
287
288  return success;
289}
290
291error_code rename(const Twine &from, const Twine &to) {
292  // Get arguments.
293  SmallString<128> from_storage;
294  SmallString<128> to_storage;
295  StringRef f = from.toStringRef(from_storage);
296  StringRef t = to.toStringRef(to_storage);
297
298  // Convert to utf-16.
299  SmallVector<wchar_t, 128> wide_from;
300  SmallVector<wchar_t, 128> wide_to;
301  if (error_code ec = UTF8ToUTF16(f, wide_from)) return ec;
302  if (error_code ec = UTF8ToUTF16(t, wide_to)) return ec;
303
304  if (!::MoveFileExW(wide_from.begin(), wide_to.begin(),
305                     MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING))
306    return windows_error(::GetLastError());
307
308  return success;
309}
310
311error_code resize_file(const Twine &path, uint64_t size) {
312  SmallString<128> path_storage;
313  SmallVector<wchar_t, 128> path_utf16;
314
315  if (error_code ec = UTF8ToUTF16(path.toStringRef(path_storage),
316                                  path_utf16))
317    return ec;
318
319  int fd = ::_wopen(path_utf16.begin(), O_BINARY, S_IREAD | S_IWRITE);
320  if (fd == -1)
321    return error_code(errno, generic_category());
322#ifdef HAVE__CHSIZE_S
323  errno_t error = ::_chsize_s(fd, size);
324#else
325  errno_t error = ::_chsize(fd, size);
326#endif
327  ::close(fd);
328  return error_code(error, generic_category());
329}
330
331error_code exists(const Twine &path, bool &result) {
332  SmallString<128> path_storage;
333  SmallVector<wchar_t, 128> path_utf16;
334
335  if (error_code ec = UTF8ToUTF16(path.toStringRef(path_storage),
336                                  path_utf16))
337    return ec;
338
339  DWORD attributes = ::GetFileAttributesW(path_utf16.begin());
340
341  if (attributes == INVALID_FILE_ATTRIBUTES) {
342    // See if the file didn't actually exist.
343    error_code ec = make_error_code(windows_error(::GetLastError()));
344    if (ec != windows_error::file_not_found &&
345        ec != windows_error::path_not_found)
346      return ec;
347    result = false;
348  } else
349    result = true;
350  return success;
351}
352
353bool equivalent(file_status A, file_status B) {
354  assert(status_known(A) && status_known(B));
355  return A.FileIndexHigh      == B.FileIndexHigh &&
356         A.FileIndexLow       == B.FileIndexLow &&
357         A.FileSizeHigh       == B.FileSizeHigh &&
358         A.FileSizeLow        == B.FileSizeLow &&
359         A.LastWriteTimeHigh  == B.LastWriteTimeHigh &&
360         A.LastWriteTimeLow   == B.LastWriteTimeLow &&
361         A.VolumeSerialNumber == B.VolumeSerialNumber;
362}
363
364error_code equivalent(const Twine &A, const Twine &B, bool &result) {
365  file_status fsA, fsB;
366  if (error_code ec = status(A, fsA)) return ec;
367  if (error_code ec = status(B, fsB)) return ec;
368  result = equivalent(fsA, fsB);
369  return success;
370}
371
372error_code file_size(const Twine &path, uint64_t &result) {
373  SmallString<128> path_storage;
374  SmallVector<wchar_t, 128> path_utf16;
375
376  if (error_code ec = UTF8ToUTF16(path.toStringRef(path_storage),
377                                  path_utf16))
378    return ec;
379
380  WIN32_FILE_ATTRIBUTE_DATA FileData;
381  if (!::GetFileAttributesExW(path_utf16.begin(),
382                              ::GetFileExInfoStandard,
383                              &FileData))
384    return windows_error(::GetLastError());
385
386  result =
387    (uint64_t(FileData.nFileSizeHigh) << (sizeof(FileData.nFileSizeLow) * 8))
388    + FileData.nFileSizeLow;
389
390  return success;
391}
392
393static bool isReservedName(StringRef path) {
394  // This list of reserved names comes from MSDN, at:
395  // http://msdn.microsoft.com/en-us/library/aa365247%28v=vs.85%29.aspx
396  static const char *sReservedNames[] = { "nul", "con", "prn", "aux",
397                              "com1", "com2", "com3", "com4", "com5", "com6",
398                              "com7", "com8", "com9", "lpt1", "lpt2", "lpt3",
399                              "lpt4", "lpt5", "lpt6", "lpt7", "lpt8", "lpt9" };
400
401  // First, check to see if this is a device namespace, which always
402  // starts with \\.\, since device namespaces are not legal file paths.
403  if (path.startswith("\\\\.\\"))
404    return true;
405
406  // Then compare against the list of ancient reserved names
407  for (size_t i = 0; i < sizeof(sReservedNames) / sizeof(const char *); ++i) {
408    if (path.equals_lower(sReservedNames[i]))
409      return true;
410  }
411
412  // The path isn't what we consider reserved.
413  return false;
414}
415
416error_code status(const Twine &path, file_status &result) {
417  SmallString<128> path_storage;
418  SmallVector<wchar_t, 128> path_utf16;
419
420  StringRef path8 = path.toStringRef(path_storage);
421  if (isReservedName(path8)) {
422    result = file_status(file_type::character_file);
423    return success;
424  }
425
426  if (error_code ec = UTF8ToUTF16(path8, path_utf16))
427    return ec;
428
429  DWORD attr = ::GetFileAttributesW(path_utf16.begin());
430  if (attr == INVALID_FILE_ATTRIBUTES)
431    goto handle_status_error;
432
433  // Handle reparse points.
434  if (attr & FILE_ATTRIBUTE_REPARSE_POINT) {
435    ScopedFileHandle h(
436      ::CreateFileW(path_utf16.begin(),
437                    0, // Attributes only.
438                    FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
439                    NULL,
440                    OPEN_EXISTING,
441                    FILE_FLAG_BACKUP_SEMANTICS,
442                    0));
443    if (!h)
444      goto handle_status_error;
445  }
446
447  if (attr & FILE_ATTRIBUTE_DIRECTORY)
448    result = file_status(file_type::directory_file);
449  else {
450    result = file_status(file_type::regular_file);
451    ScopedFileHandle h(
452      ::CreateFileW(path_utf16.begin(),
453                    0, // Attributes only.
454                    FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
455                    NULL,
456                    OPEN_EXISTING,
457                    FILE_FLAG_BACKUP_SEMANTICS,
458                    0));
459    if (!h)
460      goto handle_status_error;
461    BY_HANDLE_FILE_INFORMATION Info;
462    if (!::GetFileInformationByHandle(h, &Info))
463      goto handle_status_error;
464    result.FileIndexHigh      = Info.nFileIndexHigh;
465    result.FileIndexLow       = Info.nFileIndexLow;
466    result.FileSizeHigh       = Info.nFileSizeHigh;
467    result.FileSizeLow        = Info.nFileSizeLow;
468    result.LastWriteTimeHigh  = Info.ftLastWriteTime.dwHighDateTime;
469    result.LastWriteTimeLow   = Info.ftLastWriteTime.dwLowDateTime;
470    result.VolumeSerialNumber = Info.dwVolumeSerialNumber;
471  }
472
473  return success;
474
475handle_status_error:
476  error_code ec = windows_error(::GetLastError());
477  if (ec == windows_error::file_not_found ||
478      ec == windows_error::path_not_found)
479    result = file_status(file_type::file_not_found);
480  else if (ec == windows_error::sharing_violation)
481    result = file_status(file_type::type_unknown);
482  else {
483    result = file_status(file_type::status_error);
484    return ec;
485  }
486
487  return success;
488}
489
490error_code unique_file(const Twine &model, int &result_fd,
491                             SmallVectorImpl<char> &result_path,
492                             bool makeAbsolute) {
493  // Use result_path as temp storage.
494  result_path.set_size(0);
495  StringRef m = model.toStringRef(result_path);
496
497  SmallVector<wchar_t, 128> model_utf16;
498  if (error_code ec = UTF8ToUTF16(m, model_utf16)) return ec;
499
500  if (makeAbsolute) {
501    // Make model absolute by prepending a temp directory if it's not already.
502    bool absolute = path::is_absolute(m);
503
504    if (!absolute) {
505      SmallVector<wchar_t, 64> temp_dir;
506      if (error_code ec = TempDir(temp_dir)) return ec;
507      // Handle c: by removing it.
508      if (model_utf16.size() > 2 && model_utf16[1] == L':') {
509        model_utf16.erase(model_utf16.begin(), model_utf16.begin() + 2);
510      }
511      model_utf16.insert(model_utf16.begin(), temp_dir.begin(), temp_dir.end());
512    }
513  }
514
515  // Replace '%' with random chars. From here on, DO NOT modify model. It may be
516  // needed if the randomly chosen path already exists.
517  SmallVector<wchar_t, 128> random_path_utf16;
518
519  // Get a Crypto Provider for CryptGenRandom.
520  HCRYPTPROV HCPC;
521  if (!::CryptAcquireContextW(&HCPC,
522                              NULL,
523                              NULL,
524                              PROV_RSA_FULL,
525                              CRYPT_VERIFYCONTEXT))
526    return windows_error(::GetLastError());
527  ScopedCryptContext CryptoProvider(HCPC);
528
529retry_random_path:
530  random_path_utf16.set_size(0);
531  for (SmallVectorImpl<wchar_t>::const_iterator i = model_utf16.begin(),
532                                                e = model_utf16.end();
533                                                i != e; ++i) {
534    if (*i == L'%') {
535      BYTE val = 0;
536      if (!::CryptGenRandom(CryptoProvider, 1, &val))
537          return windows_error(::GetLastError());
538      random_path_utf16.push_back("0123456789abcdef"[val & 15]);
539    }
540    else
541      random_path_utf16.push_back(*i);
542  }
543  // Make random_path_utf16 null terminated.
544  random_path_utf16.push_back(0);
545  random_path_utf16.pop_back();
546
547  // Try to create + open the path.
548retry_create_file:
549  HANDLE TempFileHandle = ::CreateFileW(random_path_utf16.begin(),
550                                        GENERIC_READ | GENERIC_WRITE,
551                                        FILE_SHARE_READ,
552                                        NULL,
553                                        // Return ERROR_FILE_EXISTS if the file
554                                        // already exists.
555                                        CREATE_NEW,
556                                        FILE_ATTRIBUTE_TEMPORARY,
557                                        NULL);
558  if (TempFileHandle == INVALID_HANDLE_VALUE) {
559    // If the file existed, try again, otherwise, error.
560    error_code ec = windows_error(::GetLastError());
561    if (ec == windows_error::file_exists)
562      goto retry_random_path;
563    // Check for non-existing parent directories.
564    if (ec == windows_error::path_not_found) {
565      // Create the directories using result_path as temp storage.
566      if (error_code ec = UTF16ToUTF8(random_path_utf16.begin(),
567                                      random_path_utf16.size(), result_path))
568        return ec;
569      StringRef p(result_path.begin(), result_path.size());
570      SmallString<64> dir_to_create;
571      for (path::const_iterator i = path::begin(p),
572                                e = --path::end(p); i != e; ++i) {
573        path::append(dir_to_create, *i);
574        bool Exists;
575        if (error_code ec = exists(Twine(dir_to_create), Exists)) return ec;
576        if (!Exists) {
577          // If c: doesn't exist, bail.
578          if (i->endswith(":"))
579            return ec;
580
581          SmallVector<wchar_t, 64> dir_to_create_utf16;
582          if (error_code ec = UTF8ToUTF16(dir_to_create, dir_to_create_utf16))
583            return ec;
584
585          // Create the directory.
586          if (!::CreateDirectoryW(dir_to_create_utf16.begin(), NULL))
587            return windows_error(::GetLastError());
588        }
589      }
590      goto retry_create_file;
591    }
592    return ec;
593  }
594
595  // Set result_path to the utf-8 representation of the path.
596  if (error_code ec = UTF16ToUTF8(random_path_utf16.begin(),
597                                  random_path_utf16.size(), result_path)) {
598    ::CloseHandle(TempFileHandle);
599    ::DeleteFileW(random_path_utf16.begin());
600    return ec;
601  }
602
603  // Convert the Windows API file handle into a C-runtime handle.
604  int fd = ::_open_osfhandle(intptr_t(TempFileHandle), 0);
605  if (fd == -1) {
606    ::CloseHandle(TempFileHandle);
607    ::DeleteFileW(random_path_utf16.begin());
608    // MSDN doesn't say anything about _open_osfhandle setting errno or
609    // GetLastError(), so just return invalid_handle.
610    return windows_error::invalid_handle;
611  }
612
613  result_fd = fd;
614  return success;
615}
616
617error_code canonicalize(const Twine &path, SmallVectorImpl<char> &result) {
618  assert(path::is_absolute(path) && "path must be absolute!");
619  SmallString<128> path_storage;
620  StringRef p = path.toStringRef(path_storage);
621  SmallVector<wchar_t, 128> path_utf16;
622  result.set_size(0);
623
624  // Convert path to UTF-16.
625  if (error_code ec = UTF8ToUTF16(p, path_utf16))
626    return ec;
627
628  DWORD size = ::GetShortPathNameW(c_str(path_utf16), NULL, 0);
629  SmallVector<wchar_t, 128> short_path;
630  short_path.reserve(size + 1);
631  size = ::GetShortPathNameW( c_str(path_utf16)
632                            , short_path.data()
633                            , short_path.capacity());
634  if (!size)
635    return windows_error(::GetLastError());
636
637  short_path.set_size(size);
638
639  size = ::GetLongPathNameW(c_str(short_path), NULL, 0);
640  path_utf16.reserve(size + 1);
641  size = ::GetLongPathNameW( c_str(short_path)
642                           , path_utf16.data()
643                           , path_utf16.capacity());
644  if (!size)
645    return windows_error(::GetLastError());
646
647  path_utf16.set_size(size);
648
649  if (error_code ec = UTF16ToUTF8(path_utf16.data(), path_utf16.size(), result))
650    return ec;
651
652  return success;
653}
654
655error_code get_magic(const Twine &path, uint32_t len,
656                     SmallVectorImpl<char> &result) {
657  SmallString<128> path_storage;
658  SmallVector<wchar_t, 128> path_utf16;
659  result.set_size(0);
660
661  // Convert path to UTF-16.
662  if (error_code ec = UTF8ToUTF16(path.toStringRef(path_storage),
663                                  path_utf16))
664    return ec;
665
666  // Open file.
667  HANDLE file = ::CreateFileW(c_str(path_utf16),
668                              GENERIC_READ,
669                              FILE_SHARE_READ,
670                              NULL,
671                              OPEN_EXISTING,
672                              FILE_ATTRIBUTE_READONLY,
673                              NULL);
674  if (file == INVALID_HANDLE_VALUE)
675    return windows_error(::GetLastError());
676
677  // Allocate buffer.
678  result.reserve(len);
679
680  // Get magic!
681  DWORD bytes_read = 0;
682  BOOL read_success = ::ReadFile(file, result.data(), len, &bytes_read, NULL);
683  error_code ec = windows_error(::GetLastError());
684  ::CloseHandle(file);
685  if (!read_success || (bytes_read != len)) {
686    // Set result size to the number of bytes read if it's valid.
687    if (bytes_read <= len)
688      result.set_size(bytes_read);
689    // ERROR_HANDLE_EOF is mapped to errc::value_too_large.
690    return ec;
691  }
692
693  result.set_size(len);
694  return success;
695}
696
697error_code detail::directory_iterator_construct(detail::DirIterState &it,
698                                                StringRef path){
699  SmallVector<wchar_t, 128> path_utf16;
700
701  if (error_code ec = UTF8ToUTF16(path,
702                                  path_utf16))
703    return ec;
704
705  // Convert path to the format that Windows is happy with.
706  if (path_utf16.size() > 0 &&
707      !is_separator(path_utf16[path.size() - 1]) &&
708      path_utf16[path.size() - 1] != L':') {
709    path_utf16.push_back(L'\\');
710    path_utf16.push_back(L'*');
711  } else {
712    path_utf16.push_back(L'*');
713  }
714
715  //  Get the first directory entry.
716  WIN32_FIND_DATAW FirstFind;
717  ScopedFindHandle FindHandle(::FindFirstFileW(c_str(path_utf16), &FirstFind));
718  if (!FindHandle)
719    return windows_error(::GetLastError());
720
721  size_t FilenameLen = ::wcslen(FirstFind.cFileName);
722  while ((FilenameLen == 1 && FirstFind.cFileName[0] == L'.') ||
723         (FilenameLen == 2 && FirstFind.cFileName[0] == L'.' &&
724                              FirstFind.cFileName[1] == L'.'))
725    if (!::FindNextFileW(FindHandle, &FirstFind)) {
726      error_code ec = windows_error(::GetLastError());
727      // Check for end.
728      if (ec == windows_error::no_more_files)
729        return detail::directory_iterator_destruct(it);
730      return ec;
731    } else
732      FilenameLen = ::wcslen(FirstFind.cFileName);
733
734  // Construct the current directory entry.
735  SmallString<128> directory_entry_name_utf8;
736  if (error_code ec = UTF16ToUTF8(FirstFind.cFileName,
737                                  ::wcslen(FirstFind.cFileName),
738                                  directory_entry_name_utf8))
739    return ec;
740
741  it.IterationHandle = intptr_t(FindHandle.take());
742  SmallString<128> directory_entry_path(path);
743  path::append(directory_entry_path, directory_entry_name_utf8.str());
744  it.CurrentEntry = directory_entry(directory_entry_path.str());
745
746  return success;
747}
748
749error_code detail::directory_iterator_destruct(detail::DirIterState &it) {
750  if (it.IterationHandle != 0)
751    // Closes the handle if it's valid.
752    ScopedFindHandle close(HANDLE(it.IterationHandle));
753  it.IterationHandle = 0;
754  it.CurrentEntry = directory_entry();
755  return success;
756}
757
758error_code detail::directory_iterator_increment(detail::DirIterState &it) {
759  WIN32_FIND_DATAW FindData;
760  if (!::FindNextFileW(HANDLE(it.IterationHandle), &FindData)) {
761    error_code ec = windows_error(::GetLastError());
762    // Check for end.
763    if (ec == windows_error::no_more_files)
764      return detail::directory_iterator_destruct(it);
765    return ec;
766  }
767
768  size_t FilenameLen = ::wcslen(FindData.cFileName);
769  if ((FilenameLen == 1 && FindData.cFileName[0] == L'.') ||
770      (FilenameLen == 2 && FindData.cFileName[0] == L'.' &&
771                           FindData.cFileName[1] == L'.'))
772    return directory_iterator_increment(it);
773
774  SmallString<128> directory_entry_path_utf8;
775  if (error_code ec = UTF16ToUTF8(FindData.cFileName,
776                                  ::wcslen(FindData.cFileName),
777                                  directory_entry_path_utf8))
778    return ec;
779
780  it.CurrentEntry.replace_filename(Twine(directory_entry_path_utf8));
781  return success;
782}
783
784} // end namespace fs
785} // end namespace sys
786} // end namespace llvm
787