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 <propvarutil.h>
   9 #include <psapi.h>
  10 #include <shellapi.h>
  11 #include <shlobj.h>
  12 #include <time.h>
  13
  14 #include <limits>
  15 #include <string>
  16
  17 #include "base/file_path.h"
  18 #include "base/logging.h"
  19 #include "base/metrics/histogram.h"
  20 #include "base/process_util.h"
  21 #include "base/string_number_conversions.h"
  22 #include "base/string_util.h"
  23 #include "base/threading/thread_restrictions.h"
  24 #include "base/time.h"
  25 #include "base/utf_string_conversions.h"
  26 #include "base/win/pe_image.h"
  27 #include "base/win/scoped_comptr.h"
  28 #include "base/win/scoped_handle.h"
  29 #include "base/win/win_util.h"
  30 #include "base/win/windows_version.h"
  31
  32 namespace file_util {
  33
  34 namespace {
  35
  36 const DWORD kFileShareAll =
  37     FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
  38
  39 }  // namespace
  40
  41 bool AbsolutePath(FilePath* path) {
  42   base::ThreadRestrictions::AssertIOAllowed();
  43   wchar_t file_path_buf[MAX_PATH];
  44   if (!_wfullpath(file_path_buf, path->value().c_str(), MAX_PATH))
  45     return false;
  46   *path = FilePath(file_path_buf);
  47   return true;
  48 }
  49
  50 int CountFilesCreatedAfter(const FilePath& path,
  51                            const base::Time& comparison_time) {
  52   base::ThreadRestrictions::AssertIOAllowed();
  53
  54   int file_count = 0;
  55   FILETIME comparison_filetime(comparison_time.ToFileTime());
  56
  57   WIN32_FIND_DATA find_file_data;
  58   // All files in given dir
  59   std::wstring filename_spec = path.Append(L"*").value();
  60   HANDLE find_handle = FindFirstFile(filename_spec.c_str(), &find_file_data);
  61   if (find_handle != INVALID_HANDLE_VALUE) {
  62     do {
  63       // Don't count current or parent directories.
  64       if ((wcscmp(find_file_data.cFileName, L"..") == 0) ||
  65           (wcscmp(find_file_data.cFileName, L".") == 0))
  66         continue;
  67
  68       long result = CompareFileTime(&find_file_data.ftCreationTime,  // NOLINT
  69                                     &comparison_filetime);
  70       // File was created after or on comparison time
  71       if ((result == 1) || (result == 0))
  72         ++file_count;
  73     } while (FindNextFile(find_handle,  &find_file_data));
  74     FindClose(find_handle);
  75   }
  76
  77   return file_count;
  78 }
  79
  80 bool Delete(const FilePath& path, bool recursive) {
  81   base::ThreadRestrictions::AssertIOAllowed();
  82
  83   if (path.value().length() >= MAX_PATH)
  84     return false;
  85
  86   if (!recursive) {
  87     // If not recursing, then first check to see if |path| is a directory.
  88     // If it is, then remove it with RemoveDirectory.
  89     base::PlatformFileInfo file_info;
  90     if (GetFileInfo(path, &file_info) && file_info.is_directory)
  91       return RemoveDirectory(path.value().c_str()) != 0;
  92
  93     // Otherwise, it's a file, wildcard or non-existant. Try DeleteFile first
  94     // because it should be faster. If DeleteFile fails, then we fall through
  95     // to SHFileOperation, which will do the right thing.
  96     if (DeleteFile(path.value().c_str()) != 0)
  97       return true;
  98   }
  99
 100   // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
 101   // so we have to use wcscpy because wcscpy_s writes non-NULLs
 102   // into the rest of the buffer.
 103   wchar_t double_terminated_path[MAX_PATH + 1] = {0};
 104 #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
 105   if (g_bug108724_debug)
 106     LOG(WARNING) << "copying ";
 107   wcscpy(double_terminated_path, path.value().c_str());
 108
 109   SHFILEOPSTRUCT file_operation = {0};
 110   file_operation.wFunc = FO_DELETE;
 111   file_operation.pFrom = double_terminated_path;
 112   file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION;
 113   if (!recursive)
 114     file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
 115   if (g_bug108724_debug)
 116     LOG(WARNING) << "Performing shell operation";
 117   int err = SHFileOperation(&file_operation);
 118   if (g_bug108724_debug)
 119     LOG(WARNING) << "Done: " << err;
 120
 121   // Since we're passing flags to the operation telling it to be silent,
 122   // it's possible for the operation to be aborted/cancelled without err
 123   // being set (although MSDN doesn't give any scenarios for how this can
 124   // happen).  See MSDN for SHFileOperation and SHFILEOPTSTRUCT.
 125   if (file_operation.fAnyOperationsAborted)
 126     return false;
 127
 128   // Some versions of Windows return ERROR_FILE_NOT_FOUND (0x2) when deleting
 129   // an empty directory and some return 0x402 when they should be returning
 130   // ERROR_FILE_NOT_FOUND. MSDN says Vista and up won't return 0x402.
 131   return (err == 0 || err == ERROR_FILE_NOT_FOUND || err == 0x402);
 132 }
 133
 134 bool DeleteAfterReboot(const FilePath& path) {
 135   base::ThreadRestrictions::AssertIOAllowed();
 136
 137   if (path.value().length() >= MAX_PATH)
 138     return false;
 139
 140   return MoveFileEx(path.value().c_str(), NULL,
 141                     MOVEFILE_DELAY_UNTIL_REBOOT |
 142                         MOVEFILE_REPLACE_EXISTING) != FALSE;
 143 }
 144
 145 bool Move(const FilePath& from_path, const FilePath& to_path) {
 146   base::ThreadRestrictions::AssertIOAllowed();
 147
 148   // NOTE: I suspect we could support longer paths, but that would involve
 149   // analyzing all our usage of files.
 150   if (from_path.value().length() >= MAX_PATH ||
 151       to_path.value().length() >= MAX_PATH) {
 152     return false;
 153   }
 154   if (MoveFileEx(from_path.value().c_str(), to_path.value().c_str(),
 155                  MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING) != 0)
 156     return true;
 157
 158   // Keep the last error value from MoveFileEx around in case the below
 159   // fails.
 160   bool ret = false;
 161   DWORD last_error = ::GetLastError();
 162
 163   if (DirectoryExists(from_path)) {
 164     // MoveFileEx fails if moving directory across volumes. We will simulate
 165     // the move by using Copy and Delete. Ideally we could check whether
 166     // from_path and to_path are indeed in different volumes.
 167     ret = CopyAndDeleteDirectory(from_path, to_path);
 168   }
 169
 170   if (!ret) {
 171     // Leave a clue about what went wrong so that it can be (at least) picked
 172     // up by a PLOG entry.
 173     ::SetLastError(last_error);
 174   }
 175
 176   return ret;
 177 }
 178
 179 bool ReplaceFile(const FilePath& from_path, const FilePath& to_path) {
 180   base::ThreadRestrictions::AssertIOAllowed();
 181   // Try a simple move first.  It will only succeed when |to_path| doesn't
 182   // already exist.
 183   if (::MoveFile(from_path.value().c_str(), to_path.value().c_str()))
 184     return true;
 185   // Try the full-blown replace if the move fails, as ReplaceFile will only
 186   // succeed when |to_path| does exist. When writing to a network share, we may
 187   // not be able to change the ACLs. Ignore ACL errors then
 188   // (REPLACEFILE_IGNORE_MERGE_ERRORS).
 189   if (::ReplaceFile(to_path.value().c_str(), from_path.value().c_str(), NULL,
 190                     REPLACEFILE_IGNORE_MERGE_ERRORS, NULL, NULL)) {
 191     return true;
 192   }
 193   return false;
 194 }
 195
 196 bool CopyFile(const FilePath& from_path, const FilePath& to_path) {
 197   base::ThreadRestrictions::AssertIOAllowed();
 198
 199   // NOTE: I suspect we could support longer paths, but that would involve
 200   // analyzing all our usage of files.
 201   if (from_path.value().length() >= MAX_PATH ||
 202       to_path.value().length() >= MAX_PATH) {
 203     return false;
 204   }
 205   return (::CopyFile(from_path.value().c_str(), to_path.value().c_str(),
 206                      false) != 0);
 207 }
 208
 209 bool ShellCopy(const FilePath& from_path, const FilePath& to_path,
 210                bool recursive) {
 211   base::ThreadRestrictions::AssertIOAllowed();
 212
 213   // NOTE: I suspect we could support longer paths, but that would involve
 214   // analyzing all our usage of files.
 215   if (from_path.value().length() >= MAX_PATH ||
 216       to_path.value().length() >= MAX_PATH) {
 217     return false;
 218   }
 219
 220   // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
 221   // so we have to use wcscpy because wcscpy_s writes non-NULLs
 222   // into the rest of the buffer.
 223   wchar_t double_terminated_path_from[MAX_PATH + 1] = {0};
 224   wchar_t double_terminated_path_to[MAX_PATH + 1] = {0};
 225 #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
 226   wcscpy(double_terminated_path_from, from_path.value().c_str());
 227 #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
 228   wcscpy(double_terminated_path_to, to_path.value().c_str());
 229
 230   SHFILEOPSTRUCT file_operation = {0};
 231   file_operation.wFunc = FO_COPY;
 232   file_operation.pFrom = double_terminated_path_from;
 233   file_operation.pTo = double_terminated_path_to;
 234   file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION |
 235                           FOF_NOCONFIRMMKDIR;
 236   if (!recursive)
 237     file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
 238
 239   return (SHFileOperation(&file_operation) == 0);
 240 }
 241
 242 bool CopyDirectory(const FilePath& from_path, const FilePath& to_path,
 243                    bool recursive) {
 244   base::ThreadRestrictions::AssertIOAllowed();
 245
 246   if (recursive)
 247     return ShellCopy(from_path, to_path, true);
 248
 249   // The following code assumes that from path is a directory.
 250   DCHECK(DirectoryExists(from_path));
 251
 252   // Instead of creating a new directory, we copy the old one to include the
 253   // security information of the folder as part of the copy.
 254   if (!PathExists(to_path)) {
 255     // Except that Vista fails to do that, and instead do a recursive copy if
 256     // the target directory doesn't exist.
 257     if (base::win::GetVersion() >= base::win::VERSION_VISTA)
 258       CreateDirectory(to_path);
 259     else
 260       ShellCopy(from_path, to_path, false);
 261   }
 262
 263   FilePath directory = from_path.Append(L"*.*");
 264   return ShellCopy(directory, to_path, false);
 265 }
 266
 267 bool CopyAndDeleteDirectory(const FilePath& from_path,
 268                             const FilePath& to_path) {
 269   base::ThreadRestrictions::AssertIOAllowed();
 270   if (CopyDirectory(from_path, to_path, true)) {
 271     if (Delete(from_path, true)) {
 272       return true;
 273     }
 274     // Like Move, this function is not transactional, so we just
 275     // leave the copied bits behind if deleting from_path fails.
 276     // If to_path exists previously then we have already overwritten
 277     // it by now, we don't get better off by deleting the new bits.
 278   }
 279   return false;
 280 }
 281
 282
 283 bool PathExists(const FilePath& path) {
 284   base::ThreadRestrictions::AssertIOAllowed();
 285   return (GetFileAttributes(path.value().c_str()) != INVALID_FILE_ATTRIBUTES);
 286 }
 287
 288 bool PathIsWritable(const FilePath& path) {
 289   base::ThreadRestrictions::AssertIOAllowed();
 290   HANDLE dir =
 291       CreateFile(path.value().c_str(), FILE_ADD_FILE, kFileShareAll,
 292                  NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
 293
 294   if (dir == INVALID_HANDLE_VALUE)
 295     return false;
 296
 297   CloseHandle(dir);
 298   return true;
 299 }
 300
 301 bool DirectoryExists(const FilePath& path) {
 302   base::ThreadRestrictions::AssertIOAllowed();
 303   DWORD fileattr = GetFileAttributes(path.value().c_str());
 304   if (fileattr != INVALID_FILE_ATTRIBUTES)
 305     return (fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0;
 306   return false;
 307 }
 308
 309 bool GetFileCreationLocalTimeFromHandle(HANDLE file_handle,
 310                                         LPSYSTEMTIME creation_time) {
 311   base::ThreadRestrictions::AssertIOAllowed();
 312   if (!file_handle)
 313     return false;
 314
 315   FILETIME utc_filetime;
 316   if (!GetFileTime(file_handle, &utc_filetime, NULL, NULL))
 317     return false;
 318
 319   FILETIME local_filetime;
 320   if (!FileTimeToLocalFileTime(&utc_filetime, &local_filetime))
 321     return false;
 322
 323   return !!FileTimeToSystemTime(&local_filetime, creation_time);
 324 }
 325
 326 bool GetFileCreationLocalTime(const std::wstring& filename,
 327                               LPSYSTEMTIME creation_time) {
 328   base::ThreadRestrictions::AssertIOAllowed();
 329   base::win::ScopedHandle file_handle(
 330       CreateFile(filename.c_str(), GENERIC_READ, kFileShareAll, NULL,
 331                  OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL));
 332   return GetFileCreationLocalTimeFromHandle(file_handle.Get(), creation_time);
 333 }
 334
 335 bool ResolveShortcut(FilePath* path) {
 336   base::ThreadRestrictions::AssertIOAllowed();
 337
 338   HRESULT result;
 339   base::win::ScopedComPtr<IShellLink> i_shell_link;
 340   bool is_resolved = false;
 341
 342   // Get pointer to the IShellLink interface
 343   result = i_shell_link.CreateInstance(CLSID_ShellLink, NULL,
 344                                        CLSCTX_INPROC_SERVER);
 345   if (SUCCEEDED(result)) {
 346     base::win::ScopedComPtr<IPersistFile> persist;
 347     // Query IShellLink for the IPersistFile interface
 348     result = persist.QueryFrom(i_shell_link);
 349     if (SUCCEEDED(result)) {
 350       WCHAR temp_path[MAX_PATH];
 351       // Load the shell link
 352       result = persist->Load(path->value().c_str(), STGM_READ);
 353       if (SUCCEEDED(result)) {
 354         // Try to find the target of a shortcut
 355         result = i_shell_link->Resolve(0, SLR_NO_UI);
 356         if (SUCCEEDED(result)) {
 357           result = i_shell_link->GetPath(temp_path, MAX_PATH,
 358                                   NULL, SLGP_UNCPRIORITY);
 359           *path = FilePath(temp_path);
 360           is_resolved = true;
 361         }
 362       }
 363     }
 364   }
 365
 366   return is_resolved;
 367 }
 368
 369 bool CreateOrUpdateShortcutLink(const wchar_t *source,
 370                                 const wchar_t *destination,
 371                                 const wchar_t *working_dir,
 372                                 const wchar_t *arguments,
 373                                 const wchar_t *description,
 374                                 const wchar_t *icon,
 375                                 int icon_index,
 376                                 const wchar_t* app_id,
 377                                 uint32 options) {
 378   base::ThreadRestrictions::AssertIOAllowed();
 379
 380   bool create = (options & SHORTCUT_CREATE_ALWAYS) != 0;
 381
 382   // |source| is required when SHORTCUT_CREATE_ALWAYS is specified.
 383   DCHECK(source || !create);
 384
 385   // Length of arguments and description must be less than MAX_PATH.
 386   DCHECK(lstrlen(arguments) < MAX_PATH);
 387   DCHECK(lstrlen(description) < MAX_PATH);
 388
 389   base::win::ScopedComPtr<IShellLink> i_shell_link;
 390   base::win::ScopedComPtr<IPersistFile> i_persist_file;
 391
 392   // Get pointer to the IShellLink interface
 393   if (FAILED(i_shell_link.CreateInstance(CLSID_ShellLink, NULL,
 394                                          CLSCTX_INPROC_SERVER)) ||
 395       FAILED(i_persist_file.QueryFrom(i_shell_link))) {
 396     return false;
 397   }
 398
 399   if (!create && FAILED(i_persist_file->Load(destination, STGM_READWRITE)))
 400     return false;
 401
 402   if ((source || create) && FAILED(i_shell_link->SetPath(source)))
 403     return false;
 404
 405   if (working_dir && FAILED(i_shell_link->SetWorkingDirectory(working_dir)))
 406     return false;
 407
 408   if (arguments && FAILED(i_shell_link->SetArguments(arguments)))
 409     return false;
 410
 411   if (description && FAILED(i_shell_link->SetDescription(description)))
 412     return false;
 413
 414   if (icon && FAILED(i_shell_link->SetIconLocation(icon, icon_index)))
 415     return false;
 416
 417   bool is_dual_mode = (options & SHORTCUT_DUAL_MODE) != 0;
 418   if ((app_id || is_dual_mode) &&
 419       base::win::GetVersion() >= base::win::VERSION_WIN7) {
 420     base::win::ScopedComPtr<IPropertyStore> property_store;
 421     if (FAILED(property_store.QueryFrom(i_shell_link)) || !property_store.get())
 422       return false;
 423
 424     if (app_id && !base::win::SetAppIdForPropertyStore(property_store, app_id))
 425       return false;
 426     if (is_dual_mode &&
 427         !base::win::SetDualModeForPropertyStore(property_store)) {
 428       return false;
 429     }
 430   }
 431
 432   HRESULT result = i_persist_file->Save(destination, TRUE);
 433
 434   // If we successfully updated the icon, notify the shell that we have done so.
 435   if (!create && SUCCEEDED(result)) {
 436     // Release the interfaces in case the SHChangeNotify call below depends on
 437     // the operations above being fully completed.
 438     i_persist_file.Release();
 439     i_shell_link.Release();
 440
 441     SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, NULL, NULL);
 442   }
 443
 444   return SUCCEEDED(result);
 445 }
 446
 447 bool TaskbarPinShortcutLink(const wchar_t* shortcut) {
 448   base::ThreadRestrictions::AssertIOAllowed();
 449
 450   // "Pin to taskbar" is only supported after Win7.
 451   if (base::win::GetVersion() < base::win::VERSION_WIN7)
 452     return false;
 453
 454   int result = reinterpret_cast<int>(ShellExecute(NULL, L"taskbarpin", shortcut,
 455       NULL, NULL, 0));
 456   return result > 32;
 457 }
 458
 459 bool TaskbarUnpinShortcutLink(const wchar_t* shortcut) {
 460   base::ThreadRestrictions::AssertIOAllowed();
 461
 462   // "Unpin from taskbar" is only supported after Win7.
 463   if (base::win::GetVersion() < base::win::VERSION_WIN7)
 464     return false;
 465
 466   int result = reinterpret_cast<int>(ShellExecute(NULL, L"taskbarunpin",
 467       shortcut, NULL, NULL, 0));
 468   return result > 32;
 469 }
 470
 471 bool GetTempDir(FilePath* path) {
 472   base::ThreadRestrictions::AssertIOAllowed();
 473
 474   wchar_t temp_path[MAX_PATH + 1];
 475   DWORD path_len = ::GetTempPath(MAX_PATH, temp_path);
 476   if (path_len >= MAX_PATH || path_len <= 0)
 477     return false;
 478   // TODO(evanm): the old behavior of this function was to always strip the
 479   // trailing slash.  We duplicate this here, but it shouldn't be necessary
 480   // when everyone is using the appropriate FilePath APIs.
 481   *path = FilePath(temp_path).StripTrailingSeparators();
 482   return true;
 483 }
 484
 485 bool GetShmemTempDir(FilePath* path, bool executable) {
 486   return GetTempDir(path);
 487 }
 488
 489 bool CreateTemporaryFile(FilePath* path) {
 490   base::ThreadRestrictions::AssertIOAllowed();
 491
 492   FilePath temp_file;
 493
 494   if (!GetTempDir(path))
 495     return false;
 496
 497   if (CreateTemporaryFileInDir(*path, &temp_file)) {
 498     *path = temp_file;
 499     return true;
 500   }
 501
 502   return false;
 503 }
 504
 505 FILE* CreateAndOpenTemporaryShmemFile(FilePath* path, bool executable) {
 506   base::ThreadRestrictions::AssertIOAllowed();
 507   return CreateAndOpenTemporaryFile(path);
 508 }
 509
 510 // On POSIX we have semantics to create and open a temporary file
 511 // atomically.
 512 // TODO(jrg): is there equivalent call to use on Windows instead of
 513 // going 2-step?
 514 FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path) {
 515   base::ThreadRestrictions::AssertIOAllowed();
 516   if (!CreateTemporaryFileInDir(dir, path)) {
 517     return NULL;
 518   }
 519   // Open file in binary mode, to avoid problems with fwrite. On Windows
 520   // it replaces \n's with \r\n's, which may surprise you.
 521   // Reference: http://msdn.microsoft.com/en-us/library/h9t88zwz(VS.71).aspx
 522   return OpenFile(*path, "wb+");
 523 }
 524
 525 bool CreateTemporaryFileInDir(const FilePath& dir,
 526                               FilePath* temp_file) {
 527   base::ThreadRestrictions::AssertIOAllowed();
 528
 529   wchar_t temp_name[MAX_PATH + 1];
 530
 531   if (!GetTempFileName(dir.value().c_str(), L"", 0, temp_name)) {
 532     DPLOG(WARNING) << "Failed to get temporary file name in " << dir.value();
 533     return false;
 534   }
 535
 536   DWORD path_len = GetLongPathName(temp_name, temp_name, MAX_PATH);
 537   if (path_len > MAX_PATH + 1 || path_len == 0) {
 538     DPLOG(WARNING) << "Failed to get long path name for " << temp_name;
 539     return false;
 540   }
 541
 542   std::wstring temp_file_str;
 543   temp_file_str.assign(temp_name, path_len);
 544   *temp_file = FilePath(temp_file_str);
 545   return true;
 546 }
 547
 548 bool CreateTemporaryDirInDir(const FilePath& base_dir,
 549                              const FilePath::StringType& prefix,
 550                              FilePath* new_dir) {
 551   base::ThreadRestrictions::AssertIOAllowed();
 552
 553   FilePath path_to_create;
 554   srand(static_cast<uint32>(time(NULL)));
 555
 556   for (int count = 0; count < 50; ++count) {
 557     // Try create a new temporary directory with random generated name. If
 558     // the one exists, keep trying another path name until we reach some limit.
 559     string16 new_dir_name;
 560     new_dir_name.assign(prefix);
 561     new_dir_name.append(base::IntToString16(::base::GetCurrentProcId()));
 562     new_dir_name.push_back('_');
 563     new_dir_name.append(base::IntToString16(rand() % kint16max));
 564
 565     path_to_create = base_dir.Append(new_dir_name);
 566     if (::CreateDirectory(path_to_create.value().c_str(), NULL)) {
 567       *new_dir = path_to_create;
 568       return true;
 569     }
 570   }
 571
 572   return false;
 573 }
 574
 575 bool CreateNewTempDirectory(const FilePath::StringType& prefix,
 576                             FilePath* new_temp_path) {
 577   base::ThreadRestrictions::AssertIOAllowed();
 578
 579   FilePath system_temp_dir;
 580   if (!GetTempDir(&system_temp_dir))
 581     return false;
 582
 583   return CreateTemporaryDirInDir(system_temp_dir, prefix, new_temp_path);
 584 }
 585
 586 bool CreateDirectory(const FilePath& full_path) {
 587   base::ThreadRestrictions::AssertIOAllowed();
 588
 589   // If the path exists, we've succeeded if it's a directory, failed otherwise.
 590   const wchar_t* full_path_str = full_path.value().c_str();
 591   DWORD fileattr = ::GetFileAttributes(full_path_str);
 592   if (fileattr != INVALID_FILE_ATTRIBUTES) {
 593     if ((fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0) {
 594       DVLOG(1) << "CreateDirectory(" << full_path_str << "), "
 595                << "directory already exists.";
 596       return true;
 597     }
 598     DLOG(WARNING) << "CreateDirectory(" << full_path_str << "), "
 599                   << "conflicts with existing file.";
 600     return false;
 601   }
 602
 603   // Invariant:  Path does not exist as file or directory.
 604
 605   // Attempt to create the parent recursively.  This will immediately return
 606   // true if it already exists, otherwise will create all required parent
 607   // directories starting with the highest-level missing parent.
 608   FilePath parent_path(full_path.DirName());
 609   if (parent_path.value() == full_path.value()) {
 610     return false;
 611   }
 612   if (!CreateDirectory(parent_path)) {
 613     DLOG(WARNING) << "Failed to create one of the parent directories.";
 614     return false;
 615   }
 616
 617   if (!::CreateDirectory(full_path_str, NULL)) {
 618     DWORD error_code = ::GetLastError();
 619     if (error_code == ERROR_ALREADY_EXISTS && DirectoryExists(full_path)) {
 620       // This error code ERROR_ALREADY_EXISTS doesn't indicate whether we
 621       // were racing with someone creating the same directory, or a file
 622       // with the same path.  If DirectoryExists() returns true, we lost the
 623       // race to create the same directory.
 624       return true;
 625     } else {
 626       DLOG(WARNING) << "Failed to create directory " << full_path_str
 627                     << ", last error is " << error_code << ".";
 628       return false;
 629     }
 630   } else {
 631     return true;
 632   }
 633 }
 634
 635 // TODO(rkc): Work out if we want to handle NTFS junctions here or not, handle
 636 // them if we do decide to.
 637 bool IsLink(const FilePath& file_path) {
 638   return false;
 639 }
 640
 641 bool GetFileInfo(const FilePath& file_path, base::PlatformFileInfo* results) {
 642   base::ThreadRestrictions::AssertIOAllowed();
 643
 644   WIN32_FILE_ATTRIBUTE_DATA attr;
 645   if (!GetFileAttributesEx(file_path.value().c_str(),
 646                            GetFileExInfoStandard, &attr)) {
 647     return false;
 648   }
 649
 650   ULARGE_INTEGER size;
 651   size.HighPart = attr.nFileSizeHigh;
 652   size.LowPart = attr.nFileSizeLow;
 653   results->size = size.QuadPart;
 654
 655   results->is_directory =
 656       (attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 657   results->last_modified = base::Time::FromFileTime(attr.ftLastWriteTime);
 658   results->last_accessed = base::Time::FromFileTime(attr.ftLastAccessTime);
 659   results->creation_time = base::Time::FromFileTime(attr.ftCreationTime);
 660
 661   return true;
 662 }
 663
 664 FILE* OpenFile(const FilePath& filename, const char* mode) {
 665   base::ThreadRestrictions::AssertIOAllowed();
 666   std::wstring w_mode = ASCIIToWide(std::string(mode));
 667   return _wfsopen(filename.value().c_str(), w_mode.c_str(), _SH_DENYNO);
 668 }
 669
 670 FILE* OpenFile(const std::string& filename, const char* mode) {
 671   base::ThreadRestrictions::AssertIOAllowed();
 672   return _fsopen(filename.c_str(), mode, _SH_DENYNO);
 673 }
 674
 675 int ReadFile(const FilePath& filename, char* data, int size) {
 676   base::ThreadRestrictions::AssertIOAllowed();
 677   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
 678                                           GENERIC_READ,
 679                                           FILE_SHARE_READ | FILE_SHARE_WRITE,
 680                                           NULL,
 681                                           OPEN_EXISTING,
 682                                           FILE_FLAG_SEQUENTIAL_SCAN,
 683                                           NULL));
 684   if (!file)
 685     return -1;
 686
 687   DWORD read;
 688   if (::ReadFile(file, data, size, &read, NULL) &&
 689       static_cast<int>(read) == size)
 690     return read;
 691   return -1;
 692 }
 693
 694 int WriteFile(const FilePath& filename, const char* data, int size) {
 695   base::ThreadRestrictions::AssertIOAllowed();
 696   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
 697                                           GENERIC_WRITE,
 698                                           0,
 699                                           NULL,
 700                                           CREATE_ALWAYS,
 701                                           0,
 702                                           NULL));
 703   if (!file) {
 704     DLOG(WARNING) << "CreateFile failed for path " << filename.value()
 705                   << " error code=" << GetLastError();
 706     return -1;
 707   }
 708
 709   DWORD written;
 710   BOOL result = ::WriteFile(file, data, size, &written, NULL);
 711   if (result && static_cast<int>(written) == size)
 712     return written;
 713
 714   if (!result) {
 715     // WriteFile failed.
 716     DLOG(WARNING) << "writing file " << filename.value()
 717                   << " failed, error code=" << GetLastError();
 718   } else {
 719     // Didn't write all the bytes.
 720     DLOG(WARNING) << "wrote" << written << " bytes to "
 721                   << filename.value() << " expected " << size;
 722   }
 723   return -1;
 724 }
 725
 726 int AppendToFile(const FilePath& filename, const char* data, int size) {
 727   base::ThreadRestrictions::AssertIOAllowed();
 728   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
 729                                           FILE_APPEND_DATA,
 730                                           0,
 731                                           NULL,
 732                                           OPEN_EXISTING,
 733                                           0,
 734                                           NULL));
 735   if (!file) {
 736     DLOG(WARNING) << "CreateFile failed for path " << filename.value()
 737                   << " error code=" << GetLastError();
 738     return -1;
 739   }
 740
 741   DWORD written;
 742   BOOL result = ::WriteFile(file, data, size, &written, NULL);
 743   if (result && static_cast<int>(written) == size)
 744     return written;
 745
 746   if (!result) {
 747     // WriteFile failed.
 748     DLOG(WARNING) << "writing file " << filename.value()
 749                   << " failed, error code=" << GetLastError();
 750   } else {
 751     // Didn't write all the bytes.
 752     DLOG(WARNING) << "wrote" << written << " bytes to "
 753                   << filename.value() << " expected " << size;
 754   }
 755   return -1;
 756 }
 757
 758 // Gets the current working directory for the process.
 759 bool GetCurrentDirectory(FilePath* dir) {
 760   base::ThreadRestrictions::AssertIOAllowed();
 761
 762   wchar_t system_buffer[MAX_PATH];
 763   system_buffer[0] = 0;
 764   DWORD len = ::GetCurrentDirectory(MAX_PATH, system_buffer);
 765   if (len == 0 || len > MAX_PATH)
 766     return false;
 767   // TODO(evanm): the old behavior of this function was to always strip the
 768   // trailing slash.  We duplicate this here, but it shouldn't be necessary
 769   // when everyone is using the appropriate FilePath APIs.
 770   std::wstring dir_str(system_buffer);
 771   *dir = FilePath(dir_str).StripTrailingSeparators();
 772   return true;
 773 }
 774
 775 // Sets the current working directory for the process.
 776 bool SetCurrentDirectory(const FilePath& directory) {
 777   base::ThreadRestrictions::AssertIOAllowed();
 778   BOOL ret = ::SetCurrentDirectory(directory.value().c_str());
 779   return ret != 0;
 780 }
 781
 782 ///////////////////////////////////////////////
 783 // FileEnumerator
 784
 785 FileEnumerator::FileEnumerator(const FilePath& root_path,
 786                                bool recursive,
 787                                FileType file_type)
 788     : recursive_(recursive),
 789       file_type_(file_type),
 790       has_find_data_(false),
 791       find_handle_(INVALID_HANDLE_VALUE) {
 792   // INCLUDE_DOT_DOT must not be specified if recursive.
 793   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
 794   memset(&find_data_, 0, sizeof(find_data_));
 795   pending_paths_.push(root_path);
 796 }
 797
 798 FileEnumerator::FileEnumerator(const FilePath& root_path,
 799                                bool recursive,
 800                                FileType file_type,
 801                                const FilePath::StringType& pattern)
 802     : recursive_(recursive),
 803       file_type_(file_type),
 804       has_find_data_(false),
 805       pattern_(pattern),
 806       find_handle_(INVALID_HANDLE_VALUE) {
 807   // INCLUDE_DOT_DOT must not be specified if recursive.
 808   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
 809   memset(&find_data_, 0, sizeof(find_data_));
 810   pending_paths_.push(root_path);
 811 }
 812
 813 FileEnumerator::~FileEnumerator() {
 814   if (find_handle_ != INVALID_HANDLE_VALUE)
 815     FindClose(find_handle_);
 816 }
 817
 818 void FileEnumerator::GetFindInfo(FindInfo* info) {
 819   DCHECK(info);
 820
 821   if (!has_find_data_)
 822     return;
 823
 824   memcpy(info, &find_data_, sizeof(*info));
 825 }
 826
 827 // static
 828 bool FileEnumerator::IsDirectory(const FindInfo& info) {
 829   return (info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 830 }
 831
 832 // static
 833 bool FileEnumerator::IsLink(const FindInfo& info) {
 834   return false;
 835 }
 836
 837 // static
 838 FilePath FileEnumerator::GetFilename(const FindInfo& find_info) {
 839   return FilePath(find_info.cFileName);
 840 }
 841
 842 // static
 843 int64 FileEnumerator::GetFilesize(const FindInfo& find_info) {
 844   ULARGE_INTEGER size;
 845   size.HighPart = find_info.nFileSizeHigh;
 846   size.LowPart = find_info.nFileSizeLow;
 847   DCHECK_LE(size.QuadPart, std::numeric_limits<int64>::max());
 848   return static_cast<int64>(size.QuadPart);
 849 }
 850
 851 // static
 852 base::Time FileEnumerator::GetLastModifiedTime(const FindInfo& find_info) {
 853   return base::Time::FromFileTime(find_info.ftLastWriteTime);
 854 }
 855
 856 FilePath FileEnumerator::Next() {
 857   base::ThreadRestrictions::AssertIOAllowed();
 858
 859   while (has_find_data_ || !pending_paths_.empty()) {
 860     if (!has_find_data_) {
 861       // The last find FindFirstFile operation is done, prepare a new one.
 862       root_path_ = pending_paths_.top();
 863       pending_paths_.pop();
 864
 865       // Start a new find operation.
 866       FilePath src = root_path_;
 867
 868       if (pattern_.empty())
 869         src = src.Append(L"*");  // No pattern = match everything.
 870       else
 871         src = src.Append(pattern_);
 872
 873       find_handle_ = FindFirstFile(src.value().c_str(), &find_data_);
 874       has_find_data_ = true;
 875     } else {
 876       // Search for the next file/directory.
 877       if (!FindNextFile(find_handle_, &find_data_)) {
 878         FindClose(find_handle_);
 879         find_handle_ = INVALID_HANDLE_VALUE;
 880       }
 881     }
 882
 883     if (INVALID_HANDLE_VALUE == find_handle_) {
 884       has_find_data_ = false;
 885
 886       // This is reached when we have finished a directory and are advancing to
 887       // the next one in the queue. We applied the pattern (if any) to the files
 888       // in the root search directory, but for those directories which were
 889       // matched, we want to enumerate all files inside them. This will happen
 890       // when the handle is empty.
 891       pattern_ = FilePath::StringType();
 892
 893       continue;
 894     }
 895
 896     FilePath cur_file(find_data_.cFileName);
 897     if (ShouldSkip(cur_file))
 898       continue;
 899
 900     // Construct the absolute filename.
 901     cur_file = root_path_.Append(find_data_.cFileName);
 902
 903     if (find_data_.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
 904       if (recursive_) {
 905         // If |cur_file| is a directory, and we are doing recursive searching,
 906         // add it to pending_paths_ so we scan it after we finish scanning this
 907         // directory.
 908         pending_paths_.push(cur_file);
 909       }
 910       if (file_type_ & FileEnumerator::DIRECTORIES)
 911         return cur_file;
 912     } else if (file_type_ & FileEnumerator::FILES) {
 913       return cur_file;
 914     }
 915   }
 916
 917   return FilePath();
 918 }
 919
 920 ///////////////////////////////////////////////
 921 // MemoryMappedFile
 922
 923 MemoryMappedFile::MemoryMappedFile()
 924     : file_(INVALID_HANDLE_VALUE),
 925       file_mapping_(INVALID_HANDLE_VALUE),
 926       data_(NULL),
 927       length_(INVALID_FILE_SIZE) {
 928 }
 929
 930 bool MemoryMappedFile::InitializeAsImageSection(const FilePath& file_name) {
 931   if (IsValid())
 932     return false;
 933   file_ = base::CreatePlatformFile(
 934       file_name, base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_READ,
 935       NULL, NULL);
 936
 937   if (file_ == base::kInvalidPlatformFileValue) {
 938     DLOG(ERROR) << "Couldn't open " << file_name.value();
 939     return false;
 940   }
 941
 942   if (!MapFileToMemoryInternalEx(SEC_IMAGE)) {
 943     CloseHandles();
 944     return false;
 945   }
 946
 947   return true;
 948 }
 949
 950 bool MemoryMappedFile::MapFileToMemoryInternal() {
 951   return MapFileToMemoryInternalEx(0);
 952 }
 953
 954 bool MemoryMappedFile::MapFileToMemoryInternalEx(int flags) {
 955   base::ThreadRestrictions::AssertIOAllowed();
 956
 957   if (file_ == INVALID_HANDLE_VALUE)
 958     return false;
 959
 960   length_ = ::GetFileSize(file_, NULL);
 961   if (length_ == INVALID_FILE_SIZE)
 962     return false;
 963
 964   file_mapping_ = ::CreateFileMapping(file_, NULL, PAGE_READONLY | flags,
 965                                       0, 0, NULL);
 966   if (!file_mapping_) {
 967     // According to msdn, system error codes are only reserved up to 15999.
 968     // http://msdn.microsoft.com/en-us/library/ms681381(v=VS.85).aspx.
 969     UMA_HISTOGRAM_ENUMERATION("MemoryMappedFile.CreateFileMapping",
 970                               logging::GetLastSystemErrorCode(), 16000);
 971     return false;
 972   }
 973
 974   data_ = static_cast<uint8*>(
 975       ::MapViewOfFile(file_mapping_, FILE_MAP_READ, 0, 0, 0));
 976   if (!data_) {
 977     UMA_HISTOGRAM_ENUMERATION("MemoryMappedFile.MapViewOfFile",
 978                               logging::GetLastSystemErrorCode(), 16000);
 979   }
 980   return data_ != NULL;
 981 }
 982
 983 void MemoryMappedFile::CloseHandles() {
 984   if (data_)
 985     ::UnmapViewOfFile(data_);
 986   if (file_mapping_ != INVALID_HANDLE_VALUE)
 987     ::CloseHandle(file_mapping_);
 988   if (file_ != INVALID_HANDLE_VALUE)
 989     ::CloseHandle(file_);
 990
 991   data_ = NULL;
 992   file_mapping_ = file_ = INVALID_HANDLE_VALUE;
 993   length_ = INVALID_FILE_SIZE;
 994 }
 995
 996 bool HasFileBeenModifiedSince(const FileEnumerator::FindInfo& find_info,
 997                               const base::Time& cutoff_time) {
 998   base::ThreadRestrictions::AssertIOAllowed();
 999   FILETIME file_time = cutoff_time.ToFileTime();
1000   long result = CompareFileTime(&find_info.ftLastWriteTime,  // NOLINT
1001                                 &file_time);
1002   return result == 1 || result == 0;
1003 }
1004
1005 bool NormalizeFilePath(const FilePath& path, FilePath* real_path) {
1006   base::ThreadRestrictions::AssertIOAllowed();
1007   FilePath mapped_file;
1008   if (!NormalizeToNativeFilePath(path, &mapped_file))
1009     return false;
1010   // NormalizeToNativeFilePath() will return a path that starts with
1011   // "\Device\Harddisk...".  Helper DevicePathToDriveLetterPath()
1012   // will find a drive letter which maps to the path's device, so
1013   // that we return a path starting with a drive letter.
1014   return DevicePathToDriveLetterPath(mapped_file, real_path);
1015 }
1016
1017 bool DevicePathToDriveLetterPath(const FilePath& nt_device_path,
1018                                  FilePath* out_drive_letter_path) {
1019   base::ThreadRestrictions::AssertIOAllowed();
1020
1021   // Get the mapping of drive letters to device paths.
1022   const int kDriveMappingSize = 1024;
1023   wchar_t drive_mapping[kDriveMappingSize] = {'\0'};
1024   if (!::GetLogicalDriveStrings(kDriveMappingSize - 1, drive_mapping)) {
1025     DLOG(ERROR) << "Failed to get drive mapping.";
1026     return false;
1027   }
1028
1029   // The drive mapping is a sequence of null terminated strings.
1030   // The last string is empty.
1031   wchar_t* drive_map_ptr = drive_mapping;
1032   wchar_t device_path_as_string[MAX_PATH];
1033   wchar_t drive[] = L" :";
1034
1035   // For each string in the drive mapping, get the junction that links
1036   // to it.  If that junction is a prefix of |device_path|, then we
1037   // know that |drive| is the real path prefix.
1038   while (*drive_map_ptr) {
1039     drive[0] = drive_map_ptr[0];  // Copy the drive letter.
1040
1041     if (QueryDosDevice(drive, device_path_as_string, MAX_PATH)) {
1042       FilePath device_path(device_path_as_string);
1043       if (device_path == nt_device_path ||
1044           device_path.IsParent(nt_device_path)) {
1045         *out_drive_letter_path = FilePath(drive +
1046             nt_device_path.value().substr(wcslen(device_path_as_string)));
1047         return true;
1048       }
1049     }
1050     // Move to the next drive letter string, which starts one
1051     // increment after the '\0' that terminates the current string.
1052     while (*drive_map_ptr++);
1053   }
1054
1055   // No drive matched.  The path does not start with a device junction
1056   // that is mounted as a drive letter.  This means there is no drive
1057   // letter path to the volume that holds |device_path|, so fail.
1058   return false;
1059 }
1060
1061 bool NormalizeToNativeFilePath(const FilePath& path, FilePath* nt_path) {
1062   base::ThreadRestrictions::AssertIOAllowed();
1063   // In Vista, GetFinalPathNameByHandle() would give us the real path
1064   // from a file handle.  If we ever deprecate XP, consider changing the
1065   // code below to a call to GetFinalPathNameByHandle().  The method this
1066   // function uses is explained in the following msdn article:
1067   // http://msdn.microsoft.com/en-us/library/aa366789(VS.85).aspx
1068   base::win::ScopedHandle file_handle(
1069       ::CreateFile(path.value().c_str(),
1070                    GENERIC_READ,
1071                    kFileShareAll,
1072                    NULL,
1073                    OPEN_EXISTING,
1074                    FILE_ATTRIBUTE_NORMAL,
1075                    NULL));
1076   if (!file_handle)
1077     return false;
1078
1079   // Create a file mapping object.  Can't easily use MemoryMappedFile, because
1080   // we only map the first byte, and need direct access to the handle. You can
1081   // not map an empty file, this call fails in that case.
1082   base::win::ScopedHandle file_map_handle(
1083       ::CreateFileMapping(file_handle.Get(),
1084                           NULL,
1085                           PAGE_READONLY,
1086                           0,
1087                           1,  // Just one byte.  No need to look at the data.
1088                           NULL));
1089   if (!file_map_handle)
1090     return false;
1091
1092   // Use a view of the file to get the path to the file.
1093   void* file_view = MapViewOfFile(file_map_handle.Get(),
1094                                   FILE_MAP_READ, 0, 0, 1);
1095   if (!file_view)
1096     return false;
1097
1098   // The expansion of |path| into a full path may make it longer.
1099   // GetMappedFileName() will fail if the result is longer than MAX_PATH.
1100   // Pad a bit to be safe.  If kMaxPathLength is ever changed to be less
1101   // than MAX_PATH, it would be nessisary to test that GetMappedFileName()
1102   // not return kMaxPathLength.  This would mean that only part of the
1103   // path fit in |mapped_file_path|.
1104   const int kMaxPathLength = MAX_PATH + 10;
1105   wchar_t mapped_file_path[kMaxPathLength];
1106   bool success = false;
1107   HANDLE cp = GetCurrentProcess();
1108   if (::GetMappedFileNameW(cp, file_view, mapped_file_path, kMaxPathLength)) {
1109     *nt_path = FilePath(mapped_file_path);
1110     success = true;
1111   }
1112   ::UnmapViewOfFile(file_view);
1113   return success;
1114 }
1115
1116 }  // namespace file_util