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/string_number_conversions.h"
  21 #include "base/string_util.h"
  22 #include "base/threading/thread_restrictions.h"
  23 #include "base/time.h"
  24 #include "base/utf_string_conversions.h"
  25 #include "base/win/pe_image.h"
  26 #include "base/win/scoped_comptr.h"
  27 #include "base/win/scoped_handle.h"
  28 #include "base/win/win_util.h"
  29 #include "base/win/windows_version.h"
  30
  31 namespace file_util {
  32
  33 namespace {
  34
  35 const DWORD kFileShareAll =
  36     FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
  37
  38 }  // namespace
  39
  40 bool AbsolutePath(FilePath* path) {
  41   base::ThreadRestrictions::AssertIOAllowed();
  42   wchar_t file_path_buf[MAX_PATH];
  43   if (!_wfullpath(file_path_buf, path->value().c_str(), MAX_PATH))
  44     return false;
  45   *path = FilePath(file_path_buf);
  46   return true;
  47 }
  48
  49 int CountFilesCreatedAfter(const FilePath& path,
  50                            const base::Time& comparison_time) {
  51   base::ThreadRestrictions::AssertIOAllowed();
  52
  53   int file_count = 0;
  54   FILETIME comparison_filetime(comparison_time.ToFileTime());
  55
  56   WIN32_FIND_DATA find_file_data;
  57   // All files in given dir
  58   std::wstring filename_spec = path.Append(L"*").value();
  59   HANDLE find_handle = FindFirstFile(filename_spec.c_str(), &find_file_data);
  60   if (find_handle != INVALID_HANDLE_VALUE) {
  61     do {
  62       // Don't count current or parent directories.
  63       if ((wcscmp(find_file_data.cFileName, L"..") == 0) ||
  64           (wcscmp(find_file_data.cFileName, L".") == 0))
  65         continue;
  66
  67       long result = CompareFileTime(&find_file_data.ftCreationTime,  // NOLINT
  68                                     &comparison_filetime);
  69       // File was created after or on comparison time
  70       if ((result == 1) || (result == 0))
  71         ++file_count;
  72     } while (FindNextFile(find_handle,  &find_file_data));
  73     FindClose(find_handle);
  74   }
  75
  76   return file_count;
  77 }
  78
  79 bool Delete(const FilePath& path, bool recursive) {
  80   base::ThreadRestrictions::AssertIOAllowed();
  81
  82   if (path.value().length() >= MAX_PATH)
  83     return false;
  84
  85   if (!recursive) {
  86     // If not recursing, then first check to see if |path| is a directory.
  87     // If it is, then remove it with RemoveDirectory.
  88     base::PlatformFileInfo file_info;
  89     if (GetFileInfo(path, &file_info) && file_info.is_directory)
  90       return RemoveDirectory(path.value().c_str()) != 0;
  91
  92     // Otherwise, it's a file, wildcard or non-existant. Try DeleteFile first
  93     // because it should be faster. If DeleteFile fails, then we fall through
  94     // to SHFileOperation, which will do the right thing.
  95     if (DeleteFile(path.value().c_str()) != 0)
  96       return true;
  97   }
  98
  99   // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
 100   // so we have to use wcscpy because wcscpy_s writes non-NULLs
 101   // into the rest of the buffer.
 102   wchar_t double_terminated_path[MAX_PATH + 1] = {0};
 103 #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
 104   wcscpy(double_terminated_path, path.value().c_str());
 105
 106   SHFILEOPSTRUCT file_operation = {0};
 107   file_operation.wFunc = FO_DELETE;
 108   file_operation.pFrom = double_terminated_path;
 109   file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION;
 110   if (!recursive)
 111     file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
 112   int err = SHFileOperation(&file_operation);
 113
 114   // Since we're passing flags to the operation telling it to be silent,
 115   // it's possible for the operation to be aborted/cancelled without err
 116   // being set (although MSDN doesn't give any scenarios for how this can
 117   // happen).  See MSDN for SHFileOperation and SHFILEOPTSTRUCT.
 118   if (file_operation.fAnyOperationsAborted)
 119     return false;
 120
 121   // Some versions of Windows return ERROR_FILE_NOT_FOUND (0x2) when deleting
 122   // an empty directory and some return 0x402 when they should be returning
 123   // ERROR_FILE_NOT_FOUND. MSDN says Vista and up won't return 0x402.
 124   return (err == 0 || err == ERROR_FILE_NOT_FOUND || err == 0x402);
 125 }
 126
 127 bool DeleteAfterReboot(const FilePath& path) {
 128   base::ThreadRestrictions::AssertIOAllowed();
 129
 130   if (path.value().length() >= MAX_PATH)
 131     return false;
 132
 133   return MoveFileEx(path.value().c_str(), NULL,
 134                     MOVEFILE_DELAY_UNTIL_REBOOT |
 135                         MOVEFILE_REPLACE_EXISTING) != FALSE;
 136 }
 137
 138 bool Move(const FilePath& from_path, const FilePath& to_path) {
 139   base::ThreadRestrictions::AssertIOAllowed();
 140
 141   // NOTE: I suspect we could support longer paths, but that would involve
 142   // analyzing all our usage of files.
 143   if (from_path.value().length() >= MAX_PATH ||
 144       to_path.value().length() >= MAX_PATH) {
 145     return false;
 146   }
 147   if (MoveFileEx(from_path.value().c_str(), to_path.value().c_str(),
 148                  MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING) != 0)
 149     return true;
 150
 151   // Keep the last error value from MoveFileEx around in case the below
 152   // fails.
 153   bool ret = false;
 154   DWORD last_error = ::GetLastError();
 155
 156   if (DirectoryExists(from_path)) {
 157     // MoveFileEx fails if moving directory across volumes. We will simulate
 158     // the move by using Copy and Delete. Ideally we could check whether
 159     // from_path and to_path are indeed in different volumes.
 160     ret = CopyAndDeleteDirectory(from_path, to_path);
 161   }
 162
 163   if (!ret) {
 164     // Leave a clue about what went wrong so that it can be (at least) picked
 165     // up by a PLOG entry.
 166     ::SetLastError(last_error);
 167   }
 168
 169   return ret;
 170 }
 171
 172 bool ReplaceFile(const FilePath& from_path, const FilePath& to_path) {
 173   base::ThreadRestrictions::AssertIOAllowed();
 174
 175   // Make sure that the target file exists.
 176   HANDLE target_file = ::CreateFile(
 177       to_path.value().c_str(),
 178       0,
 179       FILE_SHARE_READ | FILE_SHARE_WRITE,
 180       NULL,
 181       CREATE_NEW,
 182       FILE_ATTRIBUTE_NORMAL,
 183       NULL);
 184   if (target_file != INVALID_HANDLE_VALUE)
 185     ::CloseHandle(target_file);
 186   // When writing to a network share, we may not be able to change the ACLs.
 187   // Ignore ACL errors then (REPLACEFILE_IGNORE_MERGE_ERRORS).
 188   return ::ReplaceFile(to_path.value().c_str(),
 189       from_path.value().c_str(), NULL,
 190       REPLACEFILE_IGNORE_MERGE_ERRORS, NULL, NULL) ? true : false;
 191 }
 192
 193 bool CopyFile(const FilePath& from_path, const FilePath& to_path) {
 194   base::ThreadRestrictions::AssertIOAllowed();
 195
 196   // NOTE: I suspect we could support longer paths, but that would involve
 197   // analyzing all our usage of files.
 198   if (from_path.value().length() >= MAX_PATH ||
 199       to_path.value().length() >= MAX_PATH) {
 200     return false;
 201   }
 202   return (::CopyFile(from_path.value().c_str(), to_path.value().c_str(),
 203                      false) != 0);
 204 }
 205
 206 bool ShellCopy(const FilePath& from_path, const FilePath& to_path,
 207                bool recursive) {
 208   base::ThreadRestrictions::AssertIOAllowed();
 209
 210   // NOTE: I suspect we could support longer paths, but that would involve
 211   // analyzing all our usage of files.
 212   if (from_path.value().length() >= MAX_PATH ||
 213       to_path.value().length() >= MAX_PATH) {
 214     return false;
 215   }
 216
 217   // SHFILEOPSTRUCT wants the path to be terminated with two NULLs,
 218   // so we have to use wcscpy because wcscpy_s writes non-NULLs
 219   // into the rest of the buffer.
 220   wchar_t double_terminated_path_from[MAX_PATH + 1] = {0};
 221   wchar_t double_terminated_path_to[MAX_PATH + 1] = {0};
 222 #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
 223   wcscpy(double_terminated_path_from, from_path.value().c_str());
 224 #pragma warning(suppress:4996)  // don't complain about wcscpy deprecation
 225   wcscpy(double_terminated_path_to, to_path.value().c_str());
 226
 227   SHFILEOPSTRUCT file_operation = {0};
 228   file_operation.wFunc = FO_COPY;
 229   file_operation.pFrom = double_terminated_path_from;
 230   file_operation.pTo = double_terminated_path_to;
 231   file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION |
 232                           FOF_NOCONFIRMMKDIR;
 233   if (!recursive)
 234     file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY;
 235
 236   return (SHFileOperation(&file_operation) == 0);
 237 }
 238
 239 bool CopyDirectory(const FilePath& from_path, const FilePath& to_path,
 240                    bool recursive) {
 241   base::ThreadRestrictions::AssertIOAllowed();
 242
 243   if (recursive)
 244     return ShellCopy(from_path, to_path, true);
 245
 246   // The following code assumes that from path is a directory.
 247   DCHECK(DirectoryExists(from_path));
 248
 249   // Instead of creating a new directory, we copy the old one to include the
 250   // security information of the folder as part of the copy.
 251   if (!PathExists(to_path)) {
 252     // Except that Vista fails to do that, and instead do a recursive copy if
 253     // the target directory doesn't exist.
 254     if (base::win::GetVersion() >= base::win::VERSION_VISTA)
 255       CreateDirectory(to_path);
 256     else
 257       ShellCopy(from_path, to_path, false);
 258   }
 259
 260   FilePath directory = from_path.Append(L"*.*");
 261   return ShellCopy(directory, to_path, false);
 262 }
 263
 264 bool CopyAndDeleteDirectory(const FilePath& from_path,
 265                             const FilePath& to_path) {
 266   base::ThreadRestrictions::AssertIOAllowed();
 267   if (CopyDirectory(from_path, to_path, true)) {
 268     if (Delete(from_path, true)) {
 269       return true;
 270     }
 271     // Like Move, this function is not transactional, so we just
 272     // leave the copied bits behind if deleting from_path fails.
 273     // If to_path exists previously then we have already overwritten
 274     // it by now, we don't get better off by deleting the new bits.
 275   }
 276   return false;
 277 }
 278
 279
 280 bool PathExists(const FilePath& path) {
 281   base::ThreadRestrictions::AssertIOAllowed();
 282   return (GetFileAttributes(path.value().c_str()) != INVALID_FILE_ATTRIBUTES);
 283 }
 284
 285 bool PathIsWritable(const FilePath& path) {
 286   base::ThreadRestrictions::AssertIOAllowed();
 287   HANDLE dir =
 288       CreateFile(path.value().c_str(), FILE_ADD_FILE, kFileShareAll,
 289                  NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
 290
 291   if (dir == INVALID_HANDLE_VALUE)
 292     return false;
 293
 294   CloseHandle(dir);
 295   return true;
 296 }
 297
 298 bool DirectoryExists(const FilePath& path) {
 299   base::ThreadRestrictions::AssertIOAllowed();
 300   DWORD fileattr = GetFileAttributes(path.value().c_str());
 301   if (fileattr != INVALID_FILE_ATTRIBUTES)
 302     return (fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0;
 303   return false;
 304 }
 305
 306 bool GetFileCreationLocalTimeFromHandle(HANDLE file_handle,
 307                                         LPSYSTEMTIME creation_time) {
 308   base::ThreadRestrictions::AssertIOAllowed();
 309   if (!file_handle)
 310     return false;
 311
 312   FILETIME utc_filetime;
 313   if (!GetFileTime(file_handle, &utc_filetime, NULL, NULL))
 314     return false;
 315
 316   FILETIME local_filetime;
 317   if (!FileTimeToLocalFileTime(&utc_filetime, &local_filetime))
 318     return false;
 319
 320   return !!FileTimeToSystemTime(&local_filetime, creation_time);
 321 }
 322
 323 bool GetFileCreationLocalTime(const std::wstring& filename,
 324                               LPSYSTEMTIME creation_time) {
 325   base::ThreadRestrictions::AssertIOAllowed();
 326   base::win::ScopedHandle file_handle(
 327       CreateFile(filename.c_str(), GENERIC_READ, kFileShareAll, NULL,
 328                  OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL));
 329   return GetFileCreationLocalTimeFromHandle(file_handle.Get(), creation_time);
 330 }
 331
 332 bool ResolveShortcut(FilePath* path) {
 333   base::ThreadRestrictions::AssertIOAllowed();
 334
 335   HRESULT result;
 336   base::win::ScopedComPtr<IShellLink> i_shell_link;
 337   bool is_resolved = false;
 338
 339   // Get pointer to the IShellLink interface
 340   result = i_shell_link.CreateInstance(CLSID_ShellLink, NULL,
 341                                        CLSCTX_INPROC_SERVER);
 342   if (SUCCEEDED(result)) {
 343     base::win::ScopedComPtr<IPersistFile> persist;
 344     // Query IShellLink for the IPersistFile interface
 345     result = persist.QueryFrom(i_shell_link);
 346     if (SUCCEEDED(result)) {
 347       WCHAR temp_path[MAX_PATH];
 348       // Load the shell link
 349       result = persist->Load(path->value().c_str(), STGM_READ);
 350       if (SUCCEEDED(result)) {
 351         // Try to find the target of a shortcut
 352         result = i_shell_link->Resolve(0, SLR_NO_UI);
 353         if (SUCCEEDED(result)) {
 354           result = i_shell_link->GetPath(temp_path, MAX_PATH,
 355                                   NULL, SLGP_UNCPRIORITY);
 356           *path = FilePath(temp_path);
 357           is_resolved = true;
 358         }
 359       }
 360     }
 361   }
 362
 363   return is_resolved;
 364 }
 365
 366 bool CreateShortcutLink(const wchar_t *source, const wchar_t *destination,
 367                         const wchar_t *working_dir, const wchar_t *arguments,
 368                         const wchar_t *description, const wchar_t *icon,
 369                         int icon_index, const wchar_t* app_id) {
 370   base::ThreadRestrictions::AssertIOAllowed();
 371
 372   // Length of arguments and description must be less than MAX_PATH.
 373   DCHECK(lstrlen(arguments) < MAX_PATH);
 374   DCHECK(lstrlen(description) < MAX_PATH);
 375
 376   base::win::ScopedComPtr<IShellLink> i_shell_link;
 377   base::win::ScopedComPtr<IPersistFile> i_persist_file;
 378
 379   // Get pointer to the IShellLink interface
 380   HRESULT result = i_shell_link.CreateInstance(CLSID_ShellLink, NULL,
 381                                                CLSCTX_INPROC_SERVER);
 382   if (FAILED(result))
 383     return false;
 384
 385   // Query IShellLink for the IPersistFile interface
 386   result = i_persist_file.QueryFrom(i_shell_link);
 387   if (FAILED(result))
 388     return false;
 389
 390   if (FAILED(i_shell_link->SetPath(source)))
 391     return false;
 392
 393   if (working_dir && FAILED(i_shell_link->SetWorkingDirectory(working_dir)))
 394     return false;
 395
 396   if (arguments && FAILED(i_shell_link->SetArguments(arguments)))
 397     return false;
 398
 399   if (description && FAILED(i_shell_link->SetDescription(description)))
 400     return false;
 401
 402   if (icon && FAILED(i_shell_link->SetIconLocation(icon, icon_index)))
 403     return false;
 404
 405   if (app_id && (base::win::GetVersion() >= base::win::VERSION_WIN7)) {
 406     base::win::ScopedComPtr<IPropertyStore> property_store;
 407     if (FAILED(property_store.QueryFrom(i_shell_link)))
 408       return false;
 409
 410     if (!base::win::SetAppIdForPropertyStore(property_store, app_id))
 411       return false;
 412   }
 413
 414   result = i_persist_file->Save(destination, TRUE);
 415   return SUCCEEDED(result);
 416 }
 417
 418 bool UpdateShortcutLink(const wchar_t *source, const wchar_t *destination,
 419                         const wchar_t *working_dir, const wchar_t *arguments,
 420                         const wchar_t *description, const wchar_t *icon,
 421                         int icon_index, const wchar_t* app_id) {
 422   base::ThreadRestrictions::AssertIOAllowed();
 423
 424   // Length of arguments and description must be less than MAX_PATH.
 425   DCHECK(lstrlen(arguments) < MAX_PATH);
 426   DCHECK(lstrlen(description) < MAX_PATH);
 427
 428   // Get pointer to the IPersistFile interface and load existing link
 429   base::win::ScopedComPtr<IShellLink> i_shell_link;
 430   if (FAILED(i_shell_link.CreateInstance(CLSID_ShellLink, NULL,
 431                                          CLSCTX_INPROC_SERVER)))
 432     return false;
 433
 434   base::win::ScopedComPtr<IPersistFile> i_persist_file;
 435   if (FAILED(i_persist_file.QueryFrom(i_shell_link)))
 436     return false;
 437
 438   if (FAILED(i_persist_file->Load(destination, STGM_READWRITE)))
 439     return false;
 440
 441   if (source && FAILED(i_shell_link->SetPath(source)))
 442     return false;
 443
 444   if (working_dir && FAILED(i_shell_link->SetWorkingDirectory(working_dir)))
 445     return false;
 446
 447   if (arguments && FAILED(i_shell_link->SetArguments(arguments)))
 448     return false;
 449
 450   if (description && FAILED(i_shell_link->SetDescription(description)))
 451     return false;
 452
 453   if (icon && FAILED(i_shell_link->SetIconLocation(icon, icon_index)))
 454     return false;
 455
 456   if (app_id && base::win::GetVersion() >= base::win::VERSION_WIN7) {
 457     base::win::ScopedComPtr<IPropertyStore> property_store;
 458     if (FAILED(property_store.QueryFrom(i_shell_link)))
 459       return false;
 460
 461     if (!base::win::SetAppIdForPropertyStore(property_store, app_id))
 462       return false;
 463   }
 464
 465   HRESULT result = i_persist_file->Save(destination, TRUE);
 466
 467   i_persist_file.Release();
 468   i_shell_link.Release();
 469
 470   // If we successfully updated the icon, notify the shell that we have done so.
 471   if (SUCCEEDED(result)) {
 472     SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST | SHCNF_FLUSHNOWAIT,
 473                    NULL, NULL);
 474   }
 475
 476   return SUCCEEDED(result);
 477 }
 478
 479 bool TaskbarPinShortcutLink(const wchar_t* shortcut) {
 480   base::ThreadRestrictions::AssertIOAllowed();
 481
 482   // "Pin to taskbar" is only supported after Win7.
 483   if (base::win::GetVersion() < base::win::VERSION_WIN7)
 484     return false;
 485
 486   int result = reinterpret_cast<int>(ShellExecute(NULL, L"taskbarpin", shortcut,
 487       NULL, NULL, 0));
 488   return result > 32;
 489 }
 490
 491 bool TaskbarUnpinShortcutLink(const wchar_t* shortcut) {
 492   base::ThreadRestrictions::AssertIOAllowed();
 493
 494   // "Unpin from taskbar" is only supported after Win7.
 495   if (base::win::GetVersion() < base::win::VERSION_WIN7)
 496     return false;
 497
 498   int result = reinterpret_cast<int>(ShellExecute(NULL, L"taskbarunpin",
 499       shortcut, NULL, NULL, 0));
 500   return result > 32;
 501 }
 502
 503 bool GetTempDir(FilePath* path) {
 504   base::ThreadRestrictions::AssertIOAllowed();
 505
 506   wchar_t temp_path[MAX_PATH + 1];
 507   DWORD path_len = ::GetTempPath(MAX_PATH, temp_path);
 508   if (path_len >= MAX_PATH || path_len <= 0)
 509     return false;
 510   // TODO(evanm): the old behavior of this function was to always strip the
 511   // trailing slash.  We duplicate this here, but it shouldn't be necessary
 512   // when everyone is using the appropriate FilePath APIs.
 513   *path = FilePath(temp_path).StripTrailingSeparators();
 514   return true;
 515 }
 516
 517 bool GetShmemTempDir(FilePath* path, bool executable) {
 518   return GetTempDir(path);
 519 }
 520
 521 bool CreateTemporaryFile(FilePath* path) {
 522   base::ThreadRestrictions::AssertIOAllowed();
 523
 524   FilePath temp_file;
 525
 526   if (!GetTempDir(path))
 527     return false;
 528
 529   if (CreateTemporaryFileInDir(*path, &temp_file)) {
 530     *path = temp_file;
 531     return true;
 532   }
 533
 534   return false;
 535 }
 536
 537 FILE* CreateAndOpenTemporaryShmemFile(FilePath* path, bool executable) {
 538   base::ThreadRestrictions::AssertIOAllowed();
 539   return CreateAndOpenTemporaryFile(path);
 540 }
 541
 542 // On POSIX we have semantics to create and open a temporary file
 543 // atomically.
 544 // TODO(jrg): is there equivalent call to use on Windows instead of
 545 // going 2-step?
 546 FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path) {
 547   base::ThreadRestrictions::AssertIOAllowed();
 548   if (!CreateTemporaryFileInDir(dir, path)) {
 549     return NULL;
 550   }
 551   // Open file in binary mode, to avoid problems with fwrite. On Windows
 552   // it replaces \n's with \r\n's, which may surprise you.
 553   // Reference: http://msdn.microsoft.com/en-us/library/h9t88zwz(VS.71).aspx
 554   return OpenFile(*path, "wb+");
 555 }
 556
 557 bool CreateTemporaryFileInDir(const FilePath& dir,
 558                               FilePath* temp_file) {
 559   base::ThreadRestrictions::AssertIOAllowed();
 560
 561   wchar_t temp_name[MAX_PATH + 1];
 562
 563   if (!GetTempFileName(dir.value().c_str(), L"", 0, temp_name)) {
 564     DPLOG(WARNING) << "Failed to get temporary file name in " << dir.value();
 565     return false;
 566   }
 567
 568   DWORD path_len = GetLongPathName(temp_name, temp_name, MAX_PATH);
 569   if (path_len > MAX_PATH + 1 || path_len == 0) {
 570     DPLOG(WARNING) << "Failed to get long path name for " << temp_name;
 571     return false;
 572   }
 573
 574   std::wstring temp_file_str;
 575   temp_file_str.assign(temp_name, path_len);
 576   *temp_file = FilePath(temp_file_str);
 577   return true;
 578 }
 579
 580 bool CreateTemporaryDirInDir(const FilePath& base_dir,
 581                              const FilePath::StringType& prefix,
 582                              FilePath* new_dir) {
 583   base::ThreadRestrictions::AssertIOAllowed();
 584
 585   FilePath path_to_create;
 586   srand(static_cast<uint32>(time(NULL)));
 587
 588   for (int count = 0; count < 50; ++count) {
 589     // Try create a new temporary directory with random generated name. If
 590     // the one exists, keep trying another path name until we reach some limit.
 591     string16 new_dir_name;
 592     new_dir_name.assign(prefix);
 593     new_dir_name.append(base::IntToString16(rand() % kint16max));
 594
 595     path_to_create = base_dir.Append(new_dir_name);
 596     if (::CreateDirectory(path_to_create.value().c_str(), NULL)) {
 597       *new_dir = path_to_create;
 598       return true;
 599     }
 600   }
 601
 602   return false;
 603 }
 604
 605 bool CreateNewTempDirectory(const FilePath::StringType& prefix,
 606                             FilePath* new_temp_path) {
 607   base::ThreadRestrictions::AssertIOAllowed();
 608
 609   FilePath system_temp_dir;
 610   if (!GetTempDir(&system_temp_dir))
 611     return false;
 612
 613   return CreateTemporaryDirInDir(system_temp_dir, prefix, new_temp_path);
 614 }
 615
 616 bool CreateDirectory(const FilePath& full_path) {
 617   base::ThreadRestrictions::AssertIOAllowed();
 618
 619   // If the path exists, we've succeeded if it's a directory, failed otherwise.
 620   const wchar_t* full_path_str = full_path.value().c_str();
 621   DWORD fileattr = ::GetFileAttributes(full_path_str);
 622   if (fileattr != INVALID_FILE_ATTRIBUTES) {
 623     if ((fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0) {
 624       DVLOG(1) << "CreateDirectory(" << full_path_str << "), "
 625                << "directory already exists.";
 626       return true;
 627     }
 628     DLOG(WARNING) << "CreateDirectory(" << full_path_str << "), "
 629                   << "conflicts with existing file.";
 630     return false;
 631   }
 632
 633   // Invariant:  Path does not exist as file or directory.
 634
 635   // Attempt to create the parent recursively.  This will immediately return
 636   // true if it already exists, otherwise will create all required parent
 637   // directories starting with the highest-level missing parent.
 638   FilePath parent_path(full_path.DirName());
 639   if (parent_path.value() == full_path.value()) {
 640     return false;
 641   }
 642   if (!CreateDirectory(parent_path)) {
 643     DLOG(WARNING) << "Failed to create one of the parent directories.";
 644     return false;
 645   }
 646
 647   if (!::CreateDirectory(full_path_str, NULL)) {
 648     DWORD error_code = ::GetLastError();
 649     if (error_code == ERROR_ALREADY_EXISTS && DirectoryExists(full_path)) {
 650       // This error code ERROR_ALREADY_EXISTS doesn't indicate whether we
 651       // were racing with someone creating the same directory, or a file
 652       // with the same path.  If DirectoryExists() returns true, we lost the
 653       // race to create the same directory.
 654       return true;
 655     } else {
 656       DLOG(WARNING) << "Failed to create directory " << full_path_str
 657                     << ", last error is " << error_code << ".";
 658       return false;
 659     }
 660   } else {
 661     return true;
 662   }
 663 }
 664
 665 // TODO(rkc): Work out if we want to handle NTFS junctions here or not, handle
 666 // them if we do decide to.
 667 bool IsLink(const FilePath& file_path) {
 668   return false;
 669 }
 670
 671 bool GetFileInfo(const FilePath& file_path, base::PlatformFileInfo* results) {
 672   base::ThreadRestrictions::AssertIOAllowed();
 673
 674   WIN32_FILE_ATTRIBUTE_DATA attr;
 675   if (!GetFileAttributesEx(file_path.value().c_str(),
 676                            GetFileExInfoStandard, &attr)) {
 677     return false;
 678   }
 679
 680   ULARGE_INTEGER size;
 681   size.HighPart = attr.nFileSizeHigh;
 682   size.LowPart = attr.nFileSizeLow;
 683   results->size = size.QuadPart;
 684
 685   results->is_directory =
 686       (attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 687   results->last_modified = base::Time::FromFileTime(attr.ftLastWriteTime);
 688   results->last_accessed = base::Time::FromFileTime(attr.ftLastAccessTime);
 689   results->creation_time = base::Time::FromFileTime(attr.ftCreationTime);
 690
 691   return true;
 692 }
 693
 694 FILE* OpenFile(const FilePath& filename, const char* mode) {
 695   base::ThreadRestrictions::AssertIOAllowed();
 696   std::wstring w_mode = ASCIIToWide(std::string(mode));
 697   return _wfsopen(filename.value().c_str(), w_mode.c_str(), _SH_DENYNO);
 698 }
 699
 700 FILE* OpenFile(const std::string& filename, const char* mode) {
 701   base::ThreadRestrictions::AssertIOAllowed();
 702   return _fsopen(filename.c_str(), mode, _SH_DENYNO);
 703 }
 704
 705 int ReadFile(const FilePath& filename, char* data, int size) {
 706   base::ThreadRestrictions::AssertIOAllowed();
 707   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
 708                                           GENERIC_READ,
 709                                           FILE_SHARE_READ | FILE_SHARE_WRITE,
 710                                           NULL,
 711                                           OPEN_EXISTING,
 712                                           FILE_FLAG_SEQUENTIAL_SCAN,
 713                                           NULL));
 714   if (!file)
 715     return -1;
 716
 717   DWORD read;
 718   if (::ReadFile(file, data, size, &read, NULL) &&
 719       static_cast<int>(read) == size)
 720     return read;
 721   return -1;
 722 }
 723
 724 int WriteFile(const FilePath& filename, const char* data, int size) {
 725   base::ThreadRestrictions::AssertIOAllowed();
 726   base::win::ScopedHandle file(CreateFile(filename.value().c_str(),
 727                                           GENERIC_WRITE,
 728                                           0,
 729                                           NULL,
 730                                           CREATE_ALWAYS,
 731                                           0,
 732                                           NULL));
 733   if (!file) {
 734     DLOG(WARNING) << "CreateFile failed for path " << filename.value()
 735                   << " error code=" << GetLastError();
 736     return -1;
 737   }
 738
 739   DWORD written;
 740   BOOL result = ::WriteFile(file, data, size, &written, NULL);
 741   if (result && static_cast<int>(written) == size)
 742     return written;
 743
 744   if (!result) {
 745     // WriteFile failed.
 746     DLOG(WARNING) << "writing file " << filename.value()
 747                   << " failed, error code=" << GetLastError();
 748   } else {
 749     // Didn't write all the bytes.
 750     DLOG(WARNING) << "wrote" << written << " bytes to "
 751                   << filename.value() << " expected " << size;
 752   }
 753   return -1;
 754 }
 755
 756 // Gets the current working directory for the process.
 757 bool GetCurrentDirectory(FilePath* dir) {
 758   base::ThreadRestrictions::AssertIOAllowed();
 759
 760   wchar_t system_buffer[MAX_PATH];
 761   system_buffer[0] = 0;
 762   DWORD len = ::GetCurrentDirectory(MAX_PATH, system_buffer);
 763   if (len == 0 || len > MAX_PATH)
 764     return false;
 765   // TODO(evanm): the old behavior of this function was to always strip the
 766   // trailing slash.  We duplicate this here, but it shouldn't be necessary
 767   // when everyone is using the appropriate FilePath APIs.
 768   std::wstring dir_str(system_buffer);
 769   *dir = FilePath(dir_str).StripTrailingSeparators();
 770   return true;
 771 }
 772
 773 // Sets the current working directory for the process.
 774 bool SetCurrentDirectory(const FilePath& directory) {
 775   base::ThreadRestrictions::AssertIOAllowed();
 776   BOOL ret = ::SetCurrentDirectory(directory.value().c_str());
 777   return ret != 0;
 778 }
 779
 780 ///////////////////////////////////////////////
 781 // FileEnumerator
 782
 783 FileEnumerator::FileEnumerator(const FilePath& root_path,
 784                                bool recursive,
 785                                FileType file_type)
 786     : recursive_(recursive),
 787       file_type_(file_type),
 788       has_find_data_(false),
 789       find_handle_(INVALID_HANDLE_VALUE) {
 790   // INCLUDE_DOT_DOT must not be specified if recursive.
 791   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
 792   memset(&find_data_, 0, sizeof(find_data_));
 793   pending_paths_.push(root_path);
 794 }
 795
 796 FileEnumerator::FileEnumerator(const FilePath& root_path,
 797                                bool recursive,
 798                                FileType file_type,
 799                                const FilePath::StringType& pattern)
 800     : recursive_(recursive),
 801       file_type_(file_type),
 802       has_find_data_(false),
 803       pattern_(pattern),
 804       find_handle_(INVALID_HANDLE_VALUE) {
 805   // INCLUDE_DOT_DOT must not be specified if recursive.
 806   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
 807   memset(&find_data_, 0, sizeof(find_data_));
 808   pending_paths_.push(root_path);
 809 }
 810
 811 FileEnumerator::~FileEnumerator() {
 812   if (find_handle_ != INVALID_HANDLE_VALUE)
 813     FindClose(find_handle_);
 814 }
 815
 816 void FileEnumerator::GetFindInfo(FindInfo* info) {
 817   DCHECK(info);
 818
 819   if (!has_find_data_)
 820     return;
 821
 822   memcpy(info, &find_data_, sizeof(*info));
 823 }
 824
 825 bool FileEnumerator::IsDirectory(const FindInfo& info) {
 826   return (info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 827 }
 828
 829 // static
 830 FilePath FileEnumerator::GetFilename(const FindInfo& find_info) {
 831   return FilePath(find_info.cFileName);
 832 }
 833
 834 // static
 835 int64 FileEnumerator::GetFilesize(const FindInfo& find_info) {
 836   ULARGE_INTEGER size;
 837   size.HighPart = find_info.nFileSizeHigh;
 838   size.LowPart = find_info.nFileSizeLow;
 839   DCHECK_LE(size.QuadPart, std::numeric_limits<int64>::max());
 840   return static_cast<int64>(size.QuadPart);
 841 }
 842
 843 // static
 844 base::Time FileEnumerator::GetLastModifiedTime(const FindInfo& find_info) {
 845   return base::Time::FromFileTime(find_info.ftLastWriteTime);
 846 }
 847
 848 FilePath FileEnumerator::Next() {
 849   base::ThreadRestrictions::AssertIOAllowed();
 850
 851   while (has_find_data_ || !pending_paths_.empty()) {
 852     if (!has_find_data_) {
 853       // The last find FindFirstFile operation is done, prepare a new one.
 854       root_path_ = pending_paths_.top();
 855       pending_paths_.pop();
 856
 857       // Start a new find operation.
 858       FilePath src = root_path_;
 859
 860       if (pattern_.empty())
 861         src = src.Append(L"*");  // No pattern = match everything.
 862       else
 863         src = src.Append(pattern_);
 864
 865       find_handle_ = FindFirstFile(src.value().c_str(), &find_data_);
 866       has_find_data_ = true;
 867     } else {
 868       // Search for the next file/directory.
 869       if (!FindNextFile(find_handle_, &find_data_)) {
 870         FindClose(find_handle_);
 871         find_handle_ = INVALID_HANDLE_VALUE;
 872       }
 873     }
 874
 875     if (INVALID_HANDLE_VALUE == find_handle_) {
 876       has_find_data_ = false;
 877
 878       // This is reached when we have finished a directory and are advancing to
 879       // the next one in the queue. We applied the pattern (if any) to the files
 880       // in the root search directory, but for those directories which were
 881       // matched, we want to enumerate all files inside them. This will happen
 882       // when the handle is empty.
 883       pattern_ = FilePath::StringType();
 884
 885       continue;
 886     }
 887
 888     FilePath cur_file(find_data_.cFileName);
 889     if (ShouldSkip(cur_file))
 890       continue;
 891
 892     // Construct the absolute filename.
 893     cur_file = root_path_.Append(find_data_.cFileName);
 894
 895     if (find_data_.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
 896       if (recursive_) {
 897         // If |cur_file| is a directory, and we are doing recursive searching,
 898         // add it to pending_paths_ so we scan it after we finish scanning this
 899         // directory.
 900         pending_paths_.push(cur_file);
 901       }
 902       if (file_type_ & FileEnumerator::DIRECTORIES)
 903         return cur_file;
 904     } else if (file_type_ & FileEnumerator::FILES) {
 905       return cur_file;
 906     }
 907   }
 908
 909   return FilePath();
 910 }
 911
 912 ///////////////////////////////////////////////
 913 // MemoryMappedFile
 914
 915 MemoryMappedFile::MemoryMappedFile()
 916     : file_(INVALID_HANDLE_VALUE),
 917       file_mapping_(INVALID_HANDLE_VALUE),
 918       data_(NULL),
 919       length_(INVALID_FILE_SIZE) {
 920 }
 921
 922 bool MemoryMappedFile::InitializeAsImageSection(const FilePath& file_name) {
 923   if (IsValid())
 924     return false;
 925   file_ = base::CreatePlatformFile(
 926       file_name, base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_READ,
 927       NULL, NULL);
 928
 929   if (file_ == base::kInvalidPlatformFileValue) {
 930     DLOG(ERROR) << "Couldn't open " << file_name.value();
 931     return false;
 932   }
 933
 934   if (!MapFileToMemoryInternalEx(SEC_IMAGE)) {
 935     CloseHandles();
 936     return false;
 937   }
 938
 939   return true;
 940 }
 941
 942 bool MemoryMappedFile::MapFileToMemoryInternal() {
 943   return MapFileToMemoryInternalEx(0);
 944 }
 945
 946 bool MemoryMappedFile::MapFileToMemoryInternalEx(int flags) {
 947   base::ThreadRestrictions::AssertIOAllowed();
 948
 949   if (file_ == INVALID_HANDLE_VALUE)
 950     return false;
 951
 952   length_ = ::GetFileSize(file_, NULL);
 953   if (length_ == INVALID_FILE_SIZE)
 954     return false;
 955
 956   file_mapping_ = ::CreateFileMapping(file_, NULL, PAGE_READONLY | flags,
 957                                       0, 0, NULL);
 958   if (!file_mapping_) {
 959     // According to msdn, system error codes are only reserved up to 15999.
 960     // http://msdn.microsoft.com/en-us/library/ms681381(v=VS.85).aspx.
 961     UMA_HISTOGRAM_ENUMERATION("MemoryMappedFile.CreateFileMapping",
 962                               logging::GetLastSystemErrorCode(), 16000);
 963     return false;
 964   }
 965
 966   data_ = static_cast<uint8*>(
 967       ::MapViewOfFile(file_mapping_, FILE_MAP_READ, 0, 0, 0));
 968   if (!data_) {
 969     UMA_HISTOGRAM_ENUMERATION("MemoryMappedFile.MapViewOfFile",
 970                               logging::GetLastSystemErrorCode(), 16000);
 971   }
 972   return data_ != NULL;
 973 }
 974
 975 void MemoryMappedFile::CloseHandles() {
 976   if (data_)
 977     ::UnmapViewOfFile(data_);
 978   if (file_mapping_ != INVALID_HANDLE_VALUE)
 979     ::CloseHandle(file_mapping_);
 980   if (file_ != INVALID_HANDLE_VALUE)
 981     ::CloseHandle(file_);
 982
 983   data_ = NULL;
 984   file_mapping_ = file_ = INVALID_HANDLE_VALUE;
 985   length_ = INVALID_FILE_SIZE;
 986 }
 987
 988 bool HasFileBeenModifiedSince(const FileEnumerator::FindInfo& find_info,
 989                               const base::Time& cutoff_time) {
 990   base::ThreadRestrictions::AssertIOAllowed();
 991   FILETIME file_time = cutoff_time.ToFileTime();
 992   long result = CompareFileTime(&find_info.ftLastWriteTime,  // NOLINT
 993                                 &file_time);
 994   return result == 1 || result == 0;
 995 }
 996
 997 bool NormalizeFilePath(const FilePath& path, FilePath* real_path) {
 998   base::ThreadRestrictions::AssertIOAllowed();
 999   FilePath mapped_file;
1000   if (!NormalizeToNativeFilePath(path, &mapped_file))
1001     return false;
1002   // NormalizeToNativeFilePath() will return a path that starts with
1003   // "\Device\Harddisk...".  Helper DevicePathToDriveLetterPath()
1004   // will find a drive letter which maps to the path's device, so
1005   // that we return a path starting with a drive letter.
1006   return DevicePathToDriveLetterPath(mapped_file, real_path);
1007 }
1008
1009 bool DevicePathToDriveLetterPath(const FilePath& nt_device_path,
1010                                  FilePath* out_drive_letter_path) {
1011   base::ThreadRestrictions::AssertIOAllowed();
1012
1013   // Get the mapping of drive letters to device paths.
1014   const int kDriveMappingSize = 1024;
1015   wchar_t drive_mapping[kDriveMappingSize] = {'\0'};
1016   if (!::GetLogicalDriveStrings(kDriveMappingSize - 1, drive_mapping)) {
1017     DLOG(ERROR) << "Failed to get drive mapping.";
1018     return false;
1019   }
1020
1021   // The drive mapping is a sequence of null terminated strings.
1022   // The last string is empty.
1023   wchar_t* drive_map_ptr = drive_mapping;
1024   wchar_t device_path_as_string[MAX_PATH];
1025   wchar_t drive[] = L" :";
1026
1027   // For each string in the drive mapping, get the junction that links
1028   // to it.  If that junction is a prefix of |device_path|, then we
1029   // know that |drive| is the real path prefix.
1030   while (*drive_map_ptr) {
1031     drive[0] = drive_map_ptr[0];  // Copy the drive letter.
1032
1033     if (QueryDosDevice(drive, device_path_as_string, MAX_PATH)) {
1034       FilePath device_path(device_path_as_string);
1035       if (device_path == nt_device_path ||
1036           device_path.IsParent(nt_device_path)) {
1037         *out_drive_letter_path = FilePath(drive +
1038             nt_device_path.value().substr(wcslen(device_path_as_string)));
1039         return true;
1040       }
1041     }
1042     // Move to the next drive letter string, which starts one
1043     // increment after the '\0' that terminates the current string.
1044     while (*drive_map_ptr++);
1045   }
1046
1047   // No drive matched.  The path does not start with a device junction
1048   // that is mounted as a drive letter.  This means there is no drive
1049   // letter path to the volume that holds |device_path|, so fail.
1050   return false;
1051 }
1052
1053 bool NormalizeToNativeFilePath(const FilePath& path, FilePath* nt_path) {
1054   base::ThreadRestrictions::AssertIOAllowed();
1055   // In Vista, GetFinalPathNameByHandle() would give us the real path
1056   // from a file handle.  If we ever deprecate XP, consider changing the
1057   // code below to a call to GetFinalPathNameByHandle().  The method this
1058   // function uses is explained in the following msdn article:
1059   // http://msdn.microsoft.com/en-us/library/aa366789(VS.85).aspx
1060   base::win::ScopedHandle file_handle(
1061       ::CreateFile(path.value().c_str(),
1062                    GENERIC_READ,
1063                    kFileShareAll,
1064                    NULL,
1065                    OPEN_EXISTING,
1066                    FILE_ATTRIBUTE_NORMAL,
1067                    NULL));
1068   if (!file_handle)
1069     return false;
1070
1071   // Create a file mapping object.  Can't easily use MemoryMappedFile, because
1072   // we only map the first byte, and need direct access to the handle. You can
1073   // not map an empty file, this call fails in that case.
1074   base::win::ScopedHandle file_map_handle(
1075       ::CreateFileMapping(file_handle.Get(),
1076                           NULL,
1077                           PAGE_READONLY,
1078                           0,
1079                           1,  // Just one byte.  No need to look at the data.
1080                           NULL));
1081   if (!file_map_handle)
1082     return false;
1083
1084   // Use a view of the file to get the path to the file.
1085   void* file_view = MapViewOfFile(file_map_handle.Get(),
1086                                   FILE_MAP_READ, 0, 0, 1);
1087   if (!file_view)
1088     return false;
1089
1090   // The expansion of |path| into a full path may make it longer.
1091   // GetMappedFileName() will fail if the result is longer than MAX_PATH.
1092   // Pad a bit to be safe.  If kMaxPathLength is ever changed to be less
1093   // than MAX_PATH, it would be nessisary to test that GetMappedFileName()
1094   // not return kMaxPathLength.  This would mean that only part of the
1095   // path fit in |mapped_file_path|.
1096   const int kMaxPathLength = MAX_PATH + 10;
1097   wchar_t mapped_file_path[kMaxPathLength];
1098   bool success = false;
1099   HANDLE cp = GetCurrentProcess();
1100   if (::GetMappedFileNameW(cp, file_view, mapped_file_path, kMaxPathLength)) {
1101     *nt_path = FilePath(mapped_file_path);
1102     success = true;
1103   }
1104   ::UnmapViewOfFile(file_view);
1105   return success;
1106 }
1107
1108 bool PreReadImage(const wchar_t* file_path, size_t size_to_read,
1109                   size_t step_size) {
1110   base::ThreadRestrictions::AssertIOAllowed();
1111   if (base::win::GetVersion() > base::win::VERSION_XP) {
1112     // Vista+ branch. On these OSes, the forced reads through the DLL actually
1113     // slows warm starts. The solution is to sequentially read file contents
1114     // with an optional cap on total amount to read.
1115     base::win::ScopedHandle file(
1116         CreateFile(file_path,
1117                    GENERIC_READ,
1118                    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
1119                    NULL,
1120                    OPEN_EXISTING,
1121                    FILE_FLAG_SEQUENTIAL_SCAN,
1122                    NULL));
1123
1124     if (!file.IsValid())
1125       return false;
1126
1127     // Default to 1MB sequential reads.
1128     const DWORD actual_step_size = std::max(static_cast<DWORD>(step_size),
1129                                             static_cast<DWORD>(1024*1024));
1130     LPVOID buffer = ::VirtualAlloc(NULL,
1131                                    actual_step_size,
1132                                    MEM_COMMIT,
1133                                    PAGE_READWRITE);
1134
1135     if (buffer == NULL)
1136       return false;
1137
1138     DWORD len;
1139     size_t total_read = 0;
1140     while (::ReadFile(file, buffer, actual_step_size, &len, NULL) &&
1141            len > 0 &&
1142            (size_to_read ? total_read < size_to_read : true)) {
1143       total_read += static_cast<size_t>(len);
1144     }
1145     ::VirtualFree(buffer, 0, MEM_RELEASE);
1146   } else {
1147     // WinXP branch. Here, reading the DLL from disk doesn't do
1148     // what we want so instead we pull the pages into memory by loading
1149     // the DLL and touching pages at a stride.
1150     HMODULE dll_module = ::LoadLibraryExW(
1151         file_path,
1152         NULL,
1153         LOAD_WITH_ALTERED_SEARCH_PATH | DONT_RESOLVE_DLL_REFERENCES);
1154
1155     if (!dll_module)
1156       return false;
1157
1158     base::win::PEImage pe_image(dll_module);
1159     PIMAGE_NT_HEADERS nt_headers = pe_image.GetNTHeaders();
1160     size_t actual_size_to_read = size_to_read ? size_to_read :
1161                                  nt_headers->OptionalHeader.SizeOfImage;
1162     volatile uint8* touch = reinterpret_cast<uint8*>(dll_module);
1163     size_t offset = 0;
1164     while (offset < actual_size_to_read) {
1165       uint8 unused = *(touch + offset);
1166       offset += step_size;
1167     }
1168     FreeLibrary(dll_module);
1169   }
1170
1171   return true;
1172 }
1173
1174 }  // namespace file_util