base/file_util_win.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/file_util.h"
   6
   7 #include <windows.h>
   8 #include <psapi.h>
   9 #include <shellapi.h>
  10 #include <shlobj.h>
  11 #include <time.h>
  12
  13 #include <algorithm>
  14 #include <limits>
  15 #include <string>
  16
  17 #include "base/files/file_path.h"
  18 #include "base/logging.h"
  19 #include "base/metrics/histogram.h"
  20 #include "base/process_util.h"
  21 #include "base/string_util.h"
  22 #include "base/strings/string_number_conversions.h"
  23 #include "base/threading/thread_restrictions.h"
  24 #include "base/time.h"
  25 #include "base/utf_string_conversions.h"
  26 #include "base/win/scoped_handle.h"
  27 #include "base/win/windows_version.h"
  28
  29 using base::FilePath;
  30
  31 namespace base {
  32
  33 FilePath MakeAbsoluteFilePath(const FilePath& input) {
  34   base::ThreadRestrictions::AssertIOAllowed();
  35   wchar_t file_path[MAX_PATH];
  36   if (!_wfullpath(file_path, input.value().c_str(), MAX_PATH))
  37     return FilePath();
  38   return FilePath(file_path);
  39 }
  40
  41 }  // namespace base
  42
  43 namespace file_util {
  44
  45 namespace {
  46
  47 const DWORD kFileShareAll =
  48     FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
  49
  50 }  // namespace
  51
  52 bool Delete(const FilePath& path, bool recursive) {
  53   base::ThreadRestrictions::AssertIOAllowed();
  54
  55   if (path.value().length() >= MAX_PATH)
  56     return false;
  57
  58   if (!recursive) {
  59     // If not recursing, then first check to see if |path| is a directory.
  60     // If it is, then remove it with RemoveDirectory.
  61     base::PlatformFileInfo file_info;
  62     if (GetFileInfo(path, &file_info) && file_info.is_directory)
  63       return RemoveDirectory(path.value().c_str()) != 0;
  64
  65     // Otherwise, it's a file, wildcard or non-existant. Try DeleteFile first
  66     // because it should be faster. If DeleteFile fails, then we fall through
  67     // to SHFileOperation, which will do the right thing.
  68     if (DeleteFile(path.value().c_str()) != 0)
  69       return true;
  70   }
  71
  72   // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
  73   // so we have to use wcscpy because wcscpy_s writes non-NULLs
  74   // into the rest of the buffer.
  75   wchar_t double_terminated_path[MAX_PATH + 1] = {0};
  76 #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
  77   if (g_bug108724_debug)
  78     LOG(WARNING) << "copying ";
  79   wcscpy(double_terminated_path, path.value().c_str());
  80
  81   SHFILEOPSTRUCT file_operation = {0};
  82   file_operation.wFunc = FO_DELETE;
  83   file_operation.pFrom = double_terminated_path;
  84   file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION;
  85   if (!recursive)
  86     file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
  87   if (g_bug108724_debug)
  88     LOG(WARNING) << "Performing shell operation";
  89   int err = SHFileOperation(&file_operation);
  90   if (g_bug108724_debug)
  91     LOG(WARNING) << "Done: " << err;
  92
  93   // Since we're passing flags to the operation telling it to be silent,
  94   // it's possible for the operation to be aborted/cancelled without err
  95   // being set (although MSDN doesn't give any scenarios for how this can
  96   // happen).  See MSDN for SHFileOperation and SHFILEOPTSTRUCT.
  97   if (file_operation.fAnyOperationsAborted)
  98     return false;
  99
 100   // Some versions of Windows return ERROR_FILE_NOT_FOUND (0x2) when deleting
 101   // an empty directory and some return 0x402 when they should be returning
 102   // ERROR_FILE_NOT_FOUND. MSDN says Vista and up won't return 0x402.
 103   return (err == 0 || err == ERROR_FILE_NOT_FOUND || err == 0x402);
 104 }
 105
 106 bool DeleteAfterReboot(const FilePath& path) {
 107   base::ThreadRestrictions::AssertIOAllowed();
 108
 109   if (path.value().length() >= MAX_PATH)
 110     return false;
 111
 112   return MoveFileEx(path.value().c_str(), NULL,
 113                     MOVEFILE_DELAY_UNTIL_REBOOT |
 114                         MOVEFILE_REPLACE_EXISTING) != FALSE;
 115 }
 116
 117 bool MoveUnsafe(const FilePath& from_path, const FilePath& to_path) {
 118   base::ThreadRestrictions::AssertIOAllowed();
 119
 120   // NOTE: I suspect we could support longer paths, but that would involve
 121   // analyzing all our usage of files.
 122   if (from_path.value().length() >= MAX_PATH ||
 123       to_path.value().length() >= MAX_PATH) {
 124     return false;
 125   }
 126   if (MoveFileEx(from_path.value().c_str(), to_path.value().c_str(),
 127                  MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING) != 0)
 128     return true;
 129
 130   // Keep the last error value from MoveFileEx around in case the below
 131   // fails.
 132   bool ret = false;
 133   DWORD last_error = ::GetLastError();
 134
 135   if (DirectoryExists(from_path)) {
 136     // MoveFileEx fails if moving directory across volumes. We will simulate
 137     // the move by using Copy and Delete. Ideally we could check whether
 138     // from_path and to_path are indeed in different volumes.
 139     ret = CopyAndDeleteDirectory(from_path, to_path);
 140   }
 141
 142   if (!ret) {
 143     // Leave a clue about what went wrong so that it can be (at least) picked
 144     // up by a PLOG entry.
 145     ::SetLastError(last_error);
 146   }
 147
 148   return ret;
 149 }
 150
 151 bool ReplaceFile(const FilePath& from_path, const FilePath& to_path) {
 152   base::ThreadRestrictions::AssertIOAllowed();
 153   // Try a simple move first.  It will only succeed when |to_path| doesn't
 154   // already exist.
 155   if (::MoveFile(from_path.value().c_str(), to_path.value().c_str()))
 156     return true;
 157   // Try the full-blown replace if the move fails, as ReplaceFile will only
 158   // succeed when |to_path| does exist. When writing to a network share, we may
 159   // not be able to change the ACLs. Ignore ACL errors then
 160   // (REPLACEFILE_IGNORE_MERGE_ERRORS).
 161   if (::ReplaceFile(to_path.value().c_str(), from_path.value().c_str(), NULL,
 162                     REPLACEFILE_IGNORE_MERGE_ERRORS, NULL, NULL)) {
 163     return true;
 164   }
 165   return false;
 166 }
 167
 168 bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) {
 169   base::ThreadRestrictions::AssertIOAllowed();
 170
 171   // NOTE: I suspect we could support longer paths, but that would involve
 172   // analyzing all our usage of files.
 173   if (from_path.value().length() >= MAX_PATH ||
 174       to_path.value().length() >= MAX_PATH) {
 175     return false;
 176   }
 177   return (::CopyFile(from_path.value().c_str(), to_path.value().c_str(),
 178                      false) != 0);
 179 }
 180
 181 bool ShellCopy(const FilePath& from_path, const FilePath& to_path,
 182                bool recursive) {
 183   // WinXP SHFileOperation doesn't like trailing separators.
 184   FilePath stripped_from = from_path.StripTrailingSeparators();
 185   FilePath stripped_to = to_path.StripTrailingSeparators();
 186
 187   base::ThreadRestrictions::AssertIOAllowed();
 188
 189   // NOTE: I suspect we could support longer paths, but that would involve
 190   // analyzing all our usage of files.
 191   if (stripped_from.value().length() >= MAX_PATH ||
 192       stripped_to.value().length() >= MAX_PATH) {
 193     return false;
 194   }
 195
 196   // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
 197   // so we have to use wcscpy because wcscpy_s writes non-NULLs
 198   // into the rest of the buffer.
 199   wchar_t double_terminated_path_from[MAX_PATH + 1] = {0};
 200   wchar_t double_terminated_path_to[MAX_PATH + 1] = {0};
 201 #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
 202   wcscpy(double_terminated_path_from, stripped_from.value().c_str());
 203 #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
 204   wcscpy(double_terminated_path_to, stripped_to.value().c_str());
 205
 206   SHFILEOPSTRUCT file_operation = {0};
 207   file_operation.wFunc = FO_COPY;
 208   file_operation.pFrom = double_terminated_path_from;
 209   file_operation.pTo = double_terminated_path_to;
 210   file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION |
 211                           FOF_NOCONFIRMMKDIR;
 212   if (!recursive)
 213     file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
 214
 215   return (SHFileOperation(&file_operation) == 0);
 216 }
 217
 218 bool CopyDirectory(const FilePath& from_path, const FilePath& to_path,
 219                    bool recursive) {
 220   base::ThreadRestrictions::AssertIOAllowed();
 221
 222   if (recursive)
 223     return ShellCopy(from_path, to_path, true);
 224
 225   // The following code assumes that from path is a directory.
 226   DCHECK(DirectoryExists(from_path));
 227
 228   // Instead of creating a new directory, we copy the old one to include the
 229   // security information of the folder as part of the copy.
 230   if (!PathExists(to_path)) {
 231     // Except that Vista fails to do that, and instead do a recursive copy if
 232     // the target directory doesn't exist.
 233     if (base::win::GetVersion() >= base::win::VERSION_VISTA)
 234       CreateDirectory(to_path);
 235     else
 236       ShellCopy(from_path, to_path, false);
 237   }
 238
 239   FilePath directory = from_path.Append(L"*.*");
 240   return ShellCopy(directory, to_path, false);
 241 }
 242
 243 bool CopyAndDeleteDirectory(const FilePath& from_path,
 244                             const FilePath& to_path) {
 245   base::ThreadRestrictions::AssertIOAllowed();
 246   if (CopyDirectory(from_path, to_path, true)) {
 247     if (Delete(from_path, true)) {
 248       return true;
 249     }
 250     // Like Move, this function is not transactional, so we just
 251     // leave the copied bits behind if deleting from_path fails.
 252     // If to_path exists previously then we have already overwritten
 253     // it by now, we don't get better off by deleting the new bits.
 254   }
 255   return false;
 256 }
 257
 258
 259 bool PathExists(const FilePath& path) {
 260   base::ThreadRestrictions::AssertIOAllowed();
 261   return (GetFileAttributes(path.value().c_str()) != INVALID_FILE_ATTRIBUTES);
 262 }
 263
 264 bool PathIsWritable(const FilePath& path) {
 265   base::ThreadRestrictions::AssertIOAllowed();
 266   HANDLE dir =
 267       CreateFile(path.value().c_str(), FILE_ADD_FILE, kFileShareAll,
 268                  NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
 269
 270   if (dir == INVALID_HANDLE_VALUE)
 271     return false;
 272
 273   CloseHandle(dir);
 274   return true;
 275 }
 276
 277 bool DirectoryExists(const FilePath& path) {
 278   base::ThreadRestrictions::AssertIOAllowed();
 279   DWORD fileattr = GetFileAttributes(path.value().c_str());
 280   if (fileattr != INVALID_FILE_ATTRIBUTES)
 281     return (fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0;
 282   return false;
 283 }
 284
 285 bool GetTempDir(FilePath* path) {
 286   base::ThreadRestrictions::AssertIOAllowed();
 287
 288   wchar_t temp_path[MAX_PATH + 1];
 289   DWORD path_len = ::GetTempPath(MAX_PATH, temp_path);
 290   if (path_len >= MAX_PATH || path_len <= 0)
 291     return false;
 292   // TODO(evanm): the old behavior of this function was to always strip the
 293   // trailing slash.  We duplicate this here, but it shouldn't be necessary
 294   // when everyone is using the appropriate FilePath APIs.
 295   *path = FilePath(temp_path).StripTrailingSeparators();
 296   return true;
 297 }
 298
 299 bool GetShmemTempDir(FilePath* path, bool executable) {
 300   return GetTempDir(path);
 301 }
 302
 303 bool CreateTemporaryFile(FilePath* path) {
 304   base::ThreadRestrictions::AssertIOAllowed();
 305
 306   FilePath temp_file;
 307
 308   if (!GetTempDir(path))
 309     return false;
 310
 311   if (CreateTemporaryFileInDir(*path, &temp_file)) {
 312     *path = temp_file;
 313     return true;
 314   }
 315
 316   return false;
 317 }
 318
 319 FILE* CreateAndOpenTemporaryShmemFile(FilePath* path, bool executable) {
 320   base::ThreadRestrictions::AssertIOAllowed();
 321   return CreateAndOpenTemporaryFile(path);
 322 }
 323
 324 // On POSIX we have semantics to create and open a temporary file
 325 // atomically.
 326 // TODO(jrg): is there equivalent call to use on Windows instead of
 327 // going 2-step?
 328 FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path) {
 329   base::ThreadRestrictions::AssertIOAllowed();
 330   if (!CreateTemporaryFileInDir(dir, path)) {
 331     return NULL;
 332   }
 333   // Open file in binary mode, to avoid problems with fwrite. On Windows
 334   // it replaces \n's with \r\n's, which may surprise you.
 335   // Reference: http://msdn.microsoft.com/en-us/library/h9t88zwz(VS.71).aspx
 336   return OpenFile(*path, "wb+");
 337 }
 338
 339 bool CreateTemporaryFileInDir(const FilePath& dir,
 340                               FilePath* temp_file) {
 341   base::ThreadRestrictions::AssertIOAllowed();
 342
 343   wchar_t temp_name[MAX_PATH + 1];
 344
 345   if (!GetTempFileName(dir.value().c_str(), L"", 0, temp_name)) {
 346     DPLOG(WARNING) << "Failed to get temporary file name in " << dir.value();
 347     return false;
 348   }
 349
 350   wchar_t long_temp_name[MAX_PATH + 1];
 351   DWORD long_name_len = GetLongPathName(temp_name, long_temp_name, MAX_PATH);
 352   if (long_name_len > MAX_PATH || long_name_len == 0) {
 353     // GetLongPathName() failed, but we still have a temporary file.
 354     *temp_file = FilePath(temp_name);
 355     return true;
 356   }
 357
 358   FilePath::StringType long_temp_name_str;
 359   long_temp_name_str.assign(long_temp_name, long_name_len);
 360   *temp_file = FilePath(long_temp_name_str);
 361   return true;
 362 }
 363
 364 bool CreateTemporaryDirInDir(const FilePath& base_dir,
 365                              const FilePath::StringType& prefix,
 366                              FilePath* new_dir) {
 367   base::ThreadRestrictions::AssertIOAllowed();
 368
 369   FilePath path_to_create;
 370   srand(static_cast<uint32>(time(NULL)));
 371
 372   for (int count = 0; count < 50; ++count) {
 373     // Try create a new temporary directory with random generated name. If
 374     // the one exists, keep trying another path name until we reach some limit.
 375     string16 new_dir_name;
 376     new_dir_name.assign(prefix);
 377     new_dir_name.append(base::IntToString16(::base::GetCurrentProcId()));
 378     new_dir_name.push_back('_');
 379     new_dir_name.append(base::IntToString16(rand() % kint16max));
 380
 381     path_to_create = base_dir.Append(new_dir_name);
 382     if (::CreateDirectory(path_to_create.value().c_str(), NULL)) {
 383       *new_dir = path_to_create;
 384       return true;
 385     }
 386   }
 387
 388   return false;
 389 }
 390
 391 bool CreateNewTempDirectory(const FilePath::StringType& prefix,
 392                             FilePath* new_temp_path) {
 393   base::ThreadRestrictions::AssertIOAllowed();
 394
 395   FilePath system_temp_dir;
 396   if (!GetTempDir(&system_temp_dir))
 397     return false;
 398
 399   return CreateTemporaryDirInDir(system_temp_dir, prefix, new_temp_path);
 400 }
 401
 402 bool CreateDirectory(const FilePath& full_path) {
 403   base::ThreadRestrictions::AssertIOAllowed();
 404
 405   // If the path exists, we've succeeded if it's a directory, failed otherwise.
 406   const wchar_t* full_path_str = full_path.value().c_str();
 407   DWORD fileattr = ::GetFileAttributes(full_path_str);
 408   if (fileattr != INVALID_FILE_ATTRIBUTES) {
 409     if ((fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0) {
 410       DVLOG(1) << "CreateDirectory(" << full_path_str << "), "
 411                << "directory already exists.";
 412       return true;
 413     }
 414     DLOG(WARNING) << "CreateDirectory(" << full_path_str << "), "
 415                   << "conflicts with existing file.";
 416     return false;
 417   }
 418
 419   // Invariant:  Path does not exist as file or directory.
 420
 421   // Attempt to create the parent recursively.  This will immediately return
 422   // true if it already exists, otherwise will create all required parent
 423   // directories starting with the highest-level missing parent.
 424   FilePath parent_path(full_path.DirName());
 425   if (parent_path.value() == full_path.value()) {
 426     return false;
 427   }
 428   if (!CreateDirectory(parent_path)) {
 429     DLOG(WARNING) << "Failed to create one of the parent directories.";
 430     return false;
 431   }
 432
 433   if (!::CreateDirectory(full_path_str, NULL)) {
 434     DWORD error_code = ::GetLastError();
 435     if (error_code == ERROR_ALREADY_EXISTS && DirectoryExists(full_path)) {
 436       // This error code ERROR_ALREADY_EXISTS doesn't indicate whether we
 437       // were racing with someone creating the same directory, or a file
 438       // with the same path.  If DirectoryExists() returns true, we lost the
 439       // race to create the same directory.
 440       return true;
 441     } else {
 442       DLOG(WARNING) << "Failed to create directory " << full_path_str
 443                     << ", last error is " << error_code << ".";
 444       return false;
 445     }
 446   } else {
 447     return true;
 448   }
 449 }
 450
 451 // TODO(rkc): Work out if we want to handle NTFS junctions here or not, handle
 452 // them if we do decide to.
 453 bool IsLink(const FilePath& file_path) {
 454   return false;
 455 }
 456
 457 bool GetFileInfo(const FilePath& file_path, base::PlatformFileInfo* results) {
 458   base::ThreadRestrictions::AssertIOAllowed();
 459
 460   WIN32_FILE_ATTRIBUTE_DATA attr;
 461   if (!GetFileAttributesEx(file_path.value().c_str(),
 462                            GetFileExInfoStandard, &attr)) {
 463     return false;
 464   }
 465
 466   ULARGE_INTEGER size;
 467   size.HighPart = attr.nFileSizeHigh;
 468   size.LowPart = attr.nFileSizeLow;
 469   results->size = size.QuadPart;
 470
 471   results->is_directory =
 472       (attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 473   results->last_modified = base::Time::FromFileTime(attr.ftLastWriteTime);
 474   results->last_accessed = base::Time::FromFileTime(attr.ftLastAccessTime);
 475   results->creation_time = base::Time::FromFileTime(attr.ftCreationTime);
 476
 477   return true;
 478 }
 479
 480 FILE* OpenFile(const FilePath& filename, const char* mode) {
 481   base::ThreadRestrictions::AssertIOAllowed();
 482   std::wstring w_mode = ASCIIToWide(std::string(mode));
 483   return _wfsopen(filename.value().c_str(), w_mode.c_str(), _SH_DENYNO);
 484 }
 485
 486 FILE* OpenFile(const std::string& filename, const char* mode) {
 487   base::ThreadRestrictions::AssertIOAllowed();
 488   return _fsopen(filename.c_str(), mode, _SH_DENYNO);
 489 }
 490
 491 int ReadFile(const FilePath& filename, char* data, int size) {
 492   base::ThreadRestrictions::AssertIOAllowed();
 493   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
 494                                           GENERIC_READ,
 495                                           FILE_SHARE_READ | FILE_SHARE_WRITE,
 496                                           NULL,
 497                                           OPEN_EXISTING,
 498                                           FILE_FLAG_SEQUENTIAL_SCAN,
 499                                           NULL));
 500   if (!file)
 501     return -1;
 502
 503   DWORD read;
 504   if (::ReadFile(file, data, size, &read, NULL) &&
 505       static_cast<int>(read) == size)
 506     return read;
 507   return -1;
 508 }
 509
 510 int WriteFile(const FilePath& filename, const char* data, int size) {
 511   base::ThreadRestrictions::AssertIOAllowed();
 512   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
 513                                           GENERIC_WRITE,
 514                                           0,
 515                                           NULL,
 516                                           CREATE_ALWAYS,
 517                                           0,
 518                                           NULL));
 519   if (!file) {
 520     DLOG_GETLASTERROR(WARNING) << "CreateFile failed for path "
 521                                << filename.value();
 522     return -1;
 523   }
 524
 525   DWORD written;
 526   BOOL result = ::WriteFile(file, data, size, &written, NULL);
 527   if (result && static_cast<int>(written) == size)
 528     return written;
 529
 530   if (!result) {
 531     // WriteFile failed.
 532     DLOG_GETLASTERROR(WARNING) << "writing file " << filename.value()
 533                                << " failed";
 534   } else {
 535     // Didn't write all the bytes.
 536     DLOG(WARNING) << "wrote" << written << " bytes to "
 537                   << filename.value() << " expected " << size;
 538   }
 539   return -1;
 540 }
 541
 542 int AppendToFile(const FilePath& filename, const char* data, int size) {
 543   base::ThreadRestrictions::AssertIOAllowed();
 544   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
 545                                           FILE_APPEND_DATA,
 546                                           0,
 547                                           NULL,
 548                                           OPEN_EXISTING,
 549                                           0,
 550                                           NULL));
 551   if (!file) {
 552     DLOG_GETLASTERROR(WARNING) << "CreateFile failed for path "
 553                                << filename.value();
 554     return -1;
 555   }
 556
 557   DWORD written;
 558   BOOL result = ::WriteFile(file, data, size, &written, NULL);
 559   if (result && static_cast<int>(written) == size)
 560     return written;
 561
 562   if (!result) {
 563     // WriteFile failed.
 564     DLOG_GETLASTERROR(WARNING) << "writing file " << filename.value()
 565                                << " failed";
 566   } else {
 567     // Didn't write all the bytes.
 568     DLOG(WARNING) << "wrote" << written << " bytes to "
 569                   << filename.value() << " expected " << size;
 570   }
 571   return -1;
 572 }
 573
 574 // Gets the current working directory for the process.
 575 bool GetCurrentDirectory(FilePath* dir) {
 576   base::ThreadRestrictions::AssertIOAllowed();
 577
 578   wchar_t system_buffer[MAX_PATH];
 579   system_buffer[0] = 0;
 580   DWORD len = ::GetCurrentDirectory(MAX_PATH, system_buffer);
 581   if (len == 0 || len > MAX_PATH)
 582     return false;
 583   // TODO(evanm): the old behavior of this function was to always strip the
 584   // trailing slash.  We duplicate this here, but it shouldn't be necessary
 585   // when everyone is using the appropriate FilePath APIs.
 586   std::wstring dir_str(system_buffer);
 587   *dir = FilePath(dir_str).StripTrailingSeparators();
 588   return true;
 589 }
 590
 591 // Sets the current working directory for the process.
 592 bool SetCurrentDirectory(const FilePath& directory) {
 593   base::ThreadRestrictions::AssertIOAllowed();
 594   BOOL ret = ::SetCurrentDirectory(directory.value().c_str());
 595   return ret != 0;
 596 }
 597
 598 ///////////////////////////////////////////////
 599 // FileEnumerator
 600
 601 FileEnumerator::FileEnumerator(const FilePath& root_path,
 602                                bool recursive,
 603                                int file_type)
 604     : recursive_(recursive),
 605       file_type_(file_type),
 606       has_find_data_(false),
 607       find_handle_(INVALID_HANDLE_VALUE) {
 608   // INCLUDE_DOT_DOT must not be specified if recursive.
 609   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
 610   memset(&find_data_, 0, sizeof(find_data_));
 611   pending_paths_.push(root_path);
 612 }
 613
 614 FileEnumerator::FileEnumerator(const FilePath& root_path,
 615                                bool recursive,
 616                                int file_type,
 617                                const FilePath::StringType& pattern)
 618     : recursive_(recursive),
 619       file_type_(file_type),
 620       has_find_data_(false),
 621       pattern_(pattern),
 622       find_handle_(INVALID_HANDLE_VALUE) {
 623   // INCLUDE_DOT_DOT must not be specified if recursive.
 624   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
 625   memset(&find_data_, 0, sizeof(find_data_));
 626   pending_paths_.push(root_path);
 627 }
 628
 629 FileEnumerator::~FileEnumerator() {
 630   if (find_handle_ != INVALID_HANDLE_VALUE)
 631     FindClose(find_handle_);
 632 }
 633
 634 void FileEnumerator::GetFindInfo(FindInfo* info) {
 635   DCHECK(info);
 636
 637   if (!has_find_data_)
 638     return;
 639
 640   memcpy(info, &find_data_, sizeof(*info));
 641 }
 642
 643 // static
 644 bool FileEnumerator::IsDirectory(const FindInfo& info) {
 645   return (info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 646 }
 647
 648 // static
 649 FilePath FileEnumerator::GetFilename(const FindInfo& find_info) {
 650   return FilePath(find_info.cFileName);
 651 }
 652
 653 // static
 654 int64 FileEnumerator::GetFilesize(const FindInfo& find_info) {
 655   ULARGE_INTEGER size;
 656   size.HighPart = find_info.nFileSizeHigh;
 657   size.LowPart = find_info.nFileSizeLow;
 658   DCHECK_LE(size.QuadPart, std::numeric_limits<int64>::max());
 659   return static_cast<int64>(size.QuadPart);
 660 }
 661
 662 // static
 663 base::Time FileEnumerator::GetLastModifiedTime(const FindInfo& find_info) {
 664   return base::Time::FromFileTime(find_info.ftLastWriteTime);
 665 }
 666
 667 FilePath FileEnumerator::Next() {
 668   base::ThreadRestrictions::AssertIOAllowed();
 669
 670   while (has_find_data_ || !pending_paths_.empty()) {
 671     if (!has_find_data_) {
 672       // The last find FindFirstFile operation is done, prepare a new one.
 673       root_path_ = pending_paths_.top();
 674       pending_paths_.pop();
 675
 676       // Start a new find operation.
 677       FilePath src = root_path_;
 678
 679       if (pattern_.empty())
 680         src = src.Append(L"*");  // No pattern = match everything.
 681       else
 682         src = src.Append(pattern_);
 683
 684       find_handle_ = FindFirstFile(src.value().c_str(), &find_data_);
 685       has_find_data_ = true;
 686     } else {
 687       // Search for the next file/directory.
 688       if (!FindNextFile(find_handle_, &find_data_)) {
 689         FindClose(find_handle_);
 690         find_handle_ = INVALID_HANDLE_VALUE;
 691       }
 692     }
 693
 694     if (INVALID_HANDLE_VALUE == find_handle_) {
 695       has_find_data_ = false;
 696
 697       // This is reached when we have finished a directory and are advancing to
 698       // the next one in the queue. We applied the pattern (if any) to the files
 699       // in the root search directory, but for those directories which were
 700       // matched, we want to enumerate all files inside them. This will happen
 701       // when the handle is empty.
 702       pattern_ = FilePath::StringType();
 703
 704       continue;
 705     }
 706
 707     FilePath cur_file(find_data_.cFileName);
 708     if (ShouldSkip(cur_file))
 709       continue;
 710
 711     // Construct the absolute filename.
 712     cur_file = root_path_.Append(find_data_.cFileName);
 713
 714     if (find_data_.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
 715       if (recursive_) {
 716         // If |cur_file| is a directory, and we are doing recursive searching,
 717         // add it to pending_paths_ so we scan it after we finish scanning this
 718         // directory.
 719         pending_paths_.push(cur_file);
 720       }
 721       if (file_type_ & FileEnumerator::DIRECTORIES)
 722         return cur_file;
 723     } else if (file_type_ & FileEnumerator::FILES) {
 724       return cur_file;
 725     }
 726   }
 727
 728   return FilePath();
 729 }
 730
 731 bool NormalizeFilePath(const FilePath& path, FilePath* real_path) {
 732   base::ThreadRestrictions::AssertIOAllowed();
 733   FilePath mapped_file;
 734   if (!NormalizeToNativeFilePath(path, &mapped_file))
 735     return false;
 736   // NormalizeToNativeFilePath() will return a path that starts with
 737   // "\Device\Harddisk...".  Helper DevicePathToDriveLetterPath()
 738   // will find a drive letter which maps to the path's device, so
 739   // that we return a path starting with a drive letter.
 740   return DevicePathToDriveLetterPath(mapped_file, real_path);
 741 }
 742
 743 bool DevicePathToDriveLetterPath(const FilePath& nt_device_path,
 744                                  FilePath* out_drive_letter_path) {
 745   base::ThreadRestrictions::AssertIOAllowed();
 746
 747   // Get the mapping of drive letters to device paths.
 748   const int kDriveMappingSize = 1024;
 749   wchar_t drive_mapping[kDriveMappingSize] = {'\0'};
 750   if (!::GetLogicalDriveStrings(kDriveMappingSize - 1, drive_mapping)) {
 751     DLOG(ERROR) << "Failed to get drive mapping.";
 752     return false;
 753   }
 754
 755   // The drive mapping is a sequence of null terminated strings.
 756   // The last string is empty.
 757   wchar_t* drive_map_ptr = drive_mapping;
 758   wchar_t device_path_as_string[MAX_PATH];
 759   wchar_t drive[] = L" :";
 760
 761   // For each string in the drive mapping, get the junction that links
 762   // to it.  If that junction is a prefix of |device_path|, then we
 763   // know that |drive| is the real path prefix.
 764   while (*drive_map_ptr) {
 765     drive[0] = drive_map_ptr[0];  // Copy the drive letter.
 766
 767     if (QueryDosDevice(drive, device_path_as_string, MAX_PATH)) {
 768       FilePath device_path(device_path_as_string);
 769       if (device_path == nt_device_path ||
 770           device_path.IsParent(nt_device_path)) {
 771         *out_drive_letter_path = FilePath(drive +
 772             nt_device_path.value().substr(wcslen(device_path_as_string)));
 773         return true;
 774       }
 775     }
 776     // Move to the next drive letter string, which starts one
 777     // increment after the '\0' that terminates the current string.
 778     while (*drive_map_ptr++);
 779   }
 780
 781   // No drive matched.  The path does not start with a device junction
 782   // that is mounted as a drive letter.  This means there is no drive
 783   // letter path to the volume that holds |device_path|, so fail.
 784   return false;
 785 }
 786
 787 bool NormalizeToNativeFilePath(const FilePath& path, FilePath* nt_path) {
 788   base::ThreadRestrictions::AssertIOAllowed();
 789   // In Vista, GetFinalPathNameByHandle() would give us the real path
 790   // from a file handle.  If we ever deprecate XP, consider changing the
 791   // code below to a call to GetFinalPathNameByHandle().  The method this
 792   // function uses is explained in the following msdn article:
 793   // http://msdn.microsoft.com/en-us/library/aa366789(VS.85).aspx
 794   base::win::ScopedHandle file_handle(
 795       ::CreateFile(path.value().c_str(),
 796                    GENERIC_READ,
 797                    kFileShareAll,
 798                    NULL,
 799                    OPEN_EXISTING,
 800                    FILE_ATTRIBUTE_NORMAL,
 801                    NULL));
 802   if (!file_handle)
 803     return false;
 804
 805   // Create a file mapping object.  Can't easily use MemoryMappedFile, because
 806   // we only map the first byte, and need direct access to the handle. You can
 807   // not map an empty file, this call fails in that case.
 808   base::win::ScopedHandle file_map_handle(
 809       ::CreateFileMapping(file_handle.Get(),
 810                           NULL,
 811                           PAGE_READONLY,
 812                           0,
 813                           1,  // Just one byte.  No need to look at the data.
 814                           NULL));
 815   if (!file_map_handle)
 816     return false;
 817
 818   // Use a view of the file to get the path to the file.
 819   void* file_view = MapViewOfFile(file_map_handle.Get(),
 820                                   FILE_MAP_READ, 0, 0, 1);
 821   if (!file_view)
 822     return false;
 823
 824   // The expansion of |path| into a full path may make it longer.
 825   // GetMappedFileName() will fail if the result is longer than MAX_PATH.
 826   // Pad a bit to be safe.  If kMaxPathLength is ever changed to be less
 827   // than MAX_PATH, it would be nessisary to test that GetMappedFileName()
 828   // not return kMaxPathLength.  This would mean that only part of the
 829   // path fit in |mapped_file_path|.
 830   const int kMaxPathLength = MAX_PATH + 10;
 831   wchar_t mapped_file_path[kMaxPathLength];
 832   bool success = false;
 833   HANDLE cp = GetCurrentProcess();
 834   if (::GetMappedFileNameW(cp, file_view, mapped_file_path, kMaxPathLength)) {
 835     *nt_path = FilePath(mapped_file_path);
 836     success = true;
 837   }
 838   ::UnmapViewOfFile(file_view);
 839   return success;
 840 }
 841
 842 int GetMaximumPathComponentLength(const FilePath& path) {
 843   base::ThreadRestrictions::AssertIOAllowed();
 844
 845   wchar_t volume_path[MAX_PATH];
 846   if (!GetVolumePathNameW(path.NormalizePathSeparators().value().c_str(),
 847                           volume_path,
 848                           arraysize(volume_path))) {
 849     return -1;
 850   }
 851
 852   DWORD max_length = 0;
 853   if (!GetVolumeInformationW(volume_path, NULL, 0, NULL, &max_length, NULL,
 854                              NULL, 0)) {
 855     return -1;
 856   }
 857
 858   // Length of |path| with path separator appended.
 859   size_t prefix = path.StripTrailingSeparators().value().size() + 1;
 860   // The whole path string must be shorter than MAX_PATH. That is, it must be
 861   // prefix + component_length < MAX_PATH (or equivalently, <= MAX_PATH - 1).
 862   int whole_path_limit = std::max(0, MAX_PATH - 1 - static_cast<int>(prefix));
 863   return std::min(whole_path_limit, static_cast<int>(max_length));
 864 }
 865
 866 }  // namespace file_util