base/files/file_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/files/file.h"
   6
   7 #include <io.h>
   8
   9 #include "base/files/file_path.h"
  10 #include "base/logging.h"
  11 #include "base/metrics/sparse_histogram.h"
  12 #include "base/threading/thread_restrictions.h"
  13
  14 namespace base {
  15
  16 // Make sure our Whence mappings match the system headers.
  17 COMPILE_ASSERT(File::FROM_BEGIN   == FILE_BEGIN &&
  18                File::FROM_CURRENT == FILE_CURRENT &&
  19                File::FROM_END     == FILE_END, whence_matches_system);
  20
  21 void File::InitializeUnsafe(const FilePath& name, uint32 flags) {
  22   base::ThreadRestrictions::AssertIOAllowed();
  23   DCHECK(!IsValid());
  24
  25   DWORD disposition = 0;
  26
  27   if (flags & FLAG_OPEN)
  28     disposition = OPEN_EXISTING;
  29
  30   if (flags & FLAG_CREATE) {
  31     DCHECK(!disposition);
  32     disposition = CREATE_NEW;
  33   }
  34
  35   if (flags & FLAG_OPEN_ALWAYS) {
  36     DCHECK(!disposition);
  37     disposition = OPEN_ALWAYS;
  38   }
  39
  40   if (flags & FLAG_CREATE_ALWAYS) {
  41     DCHECK(!disposition);
  42     DCHECK(flags & FLAG_WRITE);
  43     disposition = CREATE_ALWAYS;
  44   }
  45
  46   if (flags & FLAG_OPEN_TRUNCATED) {
  47     DCHECK(!disposition);
  48     DCHECK(flags & FLAG_WRITE);
  49     disposition = TRUNCATE_EXISTING;
  50   }
  51
  52   if (!disposition) {
  53     NOTREACHED();
  54     return;
  55   }
  56
  57   DWORD access = 0;
  58   if (flags & FLAG_WRITE)
  59     access = GENERIC_WRITE;
  60   if (flags & FLAG_APPEND) {
  61     DCHECK(!access);
  62     access = FILE_APPEND_DATA;
  63   }
  64   if (flags & FLAG_READ)
  65     access |= GENERIC_READ;
  66   if (flags & FLAG_WRITE_ATTRIBUTES)
  67     access |= FILE_WRITE_ATTRIBUTES;
  68   if (flags & FLAG_EXECUTE)
  69     access |= GENERIC_EXECUTE;
  70
  71   DWORD sharing = (flags & FLAG_EXCLUSIVE_READ) ? 0 : FILE_SHARE_READ;
  72   if (!(flags & FLAG_EXCLUSIVE_WRITE))
  73     sharing |= FILE_SHARE_WRITE;
  74   if (flags & FLAG_SHARE_DELETE)
  75     sharing |= FILE_SHARE_DELETE;
  76
  77   DWORD create_flags = 0;
  78   if (flags & FLAG_ASYNC)
  79     create_flags |= FILE_FLAG_OVERLAPPED;
  80   if (flags & FLAG_TEMPORARY)
  81     create_flags |= FILE_ATTRIBUTE_TEMPORARY;
  82   if (flags & FLAG_HIDDEN)
  83     create_flags |= FILE_ATTRIBUTE_HIDDEN;
  84   if (flags & FLAG_DELETE_ON_CLOSE)
  85     create_flags |= FILE_FLAG_DELETE_ON_CLOSE;
  86   if (flags & FLAG_BACKUP_SEMANTICS)
  87     create_flags |= FILE_FLAG_BACKUP_SEMANTICS;
  88
  89   file_.Set(CreateFile(name.value().c_str(), access, sharing, NULL,
  90                        disposition, create_flags, NULL));
  91
  92   if (file_.IsValid()) {
  93     error_details_ = FILE_OK;
  94     async_ = ((flags & FLAG_ASYNC) == FLAG_ASYNC);
  95
  96     if (flags & (FLAG_OPEN_ALWAYS))
  97       created_ = (ERROR_ALREADY_EXISTS != GetLastError());
  98     else if (flags & (FLAG_CREATE_ALWAYS | FLAG_CREATE))
  99       created_ = true;
 100   } else {
 101     error_details_ = OSErrorToFileError(GetLastError());
 102   }
 103 }
 104
 105 bool File::IsValid() const {
 106   return file_.IsValid();
 107 }
 108
 109 PlatformFile File::GetPlatformFile() const {
 110   return file_.Get();
 111 }
 112
 113 PlatformFile File::TakePlatformFile() {
 114   return file_.Take();
 115 }
 116
 117 void File::Close() {
 118   if (file_.IsValid()) {
 119     base::ThreadRestrictions::AssertIOAllowed();
 120     file_.Close();
 121   }
 122 }
 123
 124 int64 File::Seek(Whence whence, int64 offset) {
 125   base::ThreadRestrictions::AssertIOAllowed();
 126   DCHECK(IsValid());
 127
 128   LARGE_INTEGER distance, res;
 129   distance.QuadPart = offset;
 130   DWORD move_method = static_cast<DWORD>(whence);
 131   if (!SetFilePointerEx(file_.Get(), distance, &res, move_method))
 132     return -1;
 133   return res.QuadPart;
 134 }
 135
 136 int File::Read(int64 offset, char* data, int size) {
 137   base::ThreadRestrictions::AssertIOAllowed();
 138   DCHECK(IsValid());
 139   DCHECK(!async_);
 140   if (size < 0)
 141     return -1;
 142
 143   LARGE_INTEGER offset_li;
 144   offset_li.QuadPart = offset;
 145
 146   OVERLAPPED overlapped = {0};
 147   overlapped.Offset = offset_li.LowPart;
 148   overlapped.OffsetHigh = offset_li.HighPart;
 149
 150   DWORD bytes_read;
 151   if (::ReadFile(file_.Get(), data, size, &bytes_read, &overlapped))
 152     return bytes_read;
 153   if (ERROR_HANDLE_EOF == GetLastError())
 154     return 0;
 155
 156   return -1;
 157 }
 158
 159 int File::ReadAtCurrentPos(char* data, int size) {
 160   base::ThreadRestrictions::AssertIOAllowed();
 161   DCHECK(IsValid());
 162   DCHECK(!async_);
 163   if (size < 0)
 164     return -1;
 165
 166   DWORD bytes_read;
 167   if (::ReadFile(file_.Get(), data, size, &bytes_read, NULL))
 168     return bytes_read;
 169   if (ERROR_HANDLE_EOF == GetLastError())
 170     return 0;
 171
 172   return -1;
 173 }
 174
 175 int File::ReadNoBestEffort(int64 offset, char* data, int size) {
 176   return Read(offset, data, size);
 177 }
 178
 179 int File::ReadAtCurrentPosNoBestEffort(char* data, int size) {
 180   return ReadAtCurrentPos(data, size);
 181 }
 182
 183 int File::Write(int64 offset, const char* data, int size) {
 184   base::ThreadRestrictions::AssertIOAllowed();
 185   DCHECK(IsValid());
 186   DCHECK(!async_);
 187
 188   LARGE_INTEGER offset_li;
 189   offset_li.QuadPart = offset;
 190
 191   OVERLAPPED overlapped = {0};
 192   overlapped.Offset = offset_li.LowPart;
 193   overlapped.OffsetHigh = offset_li.HighPart;
 194
 195   DWORD bytes_written;
 196   if (::WriteFile(file_.Get(), data, size, &bytes_written, &overlapped))
 197     return bytes_written;
 198
 199   return -1;
 200 }
 201
 202 int File::WriteAtCurrentPos(const char* data, int size) {
 203   base::ThreadRestrictions::AssertIOAllowed();
 204   DCHECK(IsValid());
 205   DCHECK(!async_);
 206   if (size < 0)
 207     return -1;
 208
 209   DWORD bytes_written;
 210   if (::WriteFile(file_.Get(), data, size, &bytes_written, NULL))
 211     return bytes_written;
 212
 213   return -1;
 214 }
 215
 216 int File::WriteAtCurrentPosNoBestEffort(const char* data, int size) {
 217   return WriteAtCurrentPos(data, size);
 218 }
 219
 220 int64 File::GetLength() {
 221   base::ThreadRestrictions::AssertIOAllowed();
 222   DCHECK(IsValid());
 223   LARGE_INTEGER size;
 224   if (!::GetFileSizeEx(file_.Get(), &size))
 225     return -1;
 226
 227   return static_cast<int64>(size.QuadPart);
 228 }
 229
 230 bool File::SetLength(int64 length) {
 231   base::ThreadRestrictions::AssertIOAllowed();
 232   DCHECK(IsValid());
 233
 234   // Get the current file pointer.
 235   LARGE_INTEGER file_pointer;
 236   LARGE_INTEGER zero;
 237   zero.QuadPart = 0;
 238   if (!::SetFilePointerEx(file_.Get(), zero, &file_pointer, FILE_CURRENT))
 239     return false;
 240
 241   LARGE_INTEGER length_li;
 242   length_li.QuadPart = length;
 243   // If length > file size, SetFilePointerEx() should extend the file
 244   // with zeroes on all Windows standard file systems (NTFS, FATxx).
 245   if (!::SetFilePointerEx(file_.Get(), length_li, NULL, FILE_BEGIN))
 246     return false;
 247
 248   // Set the new file length and move the file pointer to its old position.
 249   // This is consistent with ftruncate()'s behavior, even when the file
 250   // pointer points to a location beyond the end of the file.
 251   // TODO(rvargas): Emulating ftruncate details seem suspicious and it is not
 252   // promised by the interface (nor was promised by PlatformFile). See if this
 253   // implementation detail can be removed.
 254   return ((::SetEndOfFile(file_.Get()) != FALSE) &&
 255           (::SetFilePointerEx(file_.Get(), file_pointer, NULL, FILE_BEGIN) !=
 256            FALSE));
 257 }
 258
 259 bool File::Flush() {
 260   base::ThreadRestrictions::AssertIOAllowed();
 261   DCHECK(IsValid());
 262   return ::FlushFileBuffers(file_.Get()) != FALSE;
 263 }
 264
 265 bool File::SetTimes(Time last_access_time, Time last_modified_time) {
 266   base::ThreadRestrictions::AssertIOAllowed();
 267   DCHECK(IsValid());
 268
 269   FILETIME last_access_filetime = last_access_time.ToFileTime();
 270   FILETIME last_modified_filetime = last_modified_time.ToFileTime();
 271   return (::SetFileTime(file_.Get(), NULL, &last_access_filetime,
 272                         &last_modified_filetime) != FALSE);
 273 }
 274
 275 bool File::GetInfo(Info* info) {
 276   base::ThreadRestrictions::AssertIOAllowed();
 277   DCHECK(IsValid());
 278
 279   BY_HANDLE_FILE_INFORMATION file_info;
 280   if (!GetFileInformationByHandle(file_.Get(), &file_info))
 281     return false;
 282
 283   LARGE_INTEGER size;
 284   size.HighPart = file_info.nFileSizeHigh;
 285   size.LowPart = file_info.nFileSizeLow;
 286   info->size = size.QuadPart;
 287   info->is_directory =
 288       (file_info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 289   info->is_symbolic_link = false;  // Windows doesn't have symbolic links.
 290   info->last_modified = base::Time::FromFileTime(file_info.ftLastWriteTime);
 291   info->last_accessed = base::Time::FromFileTime(file_info.ftLastAccessTime);
 292   info->creation_time = base::Time::FromFileTime(file_info.ftCreationTime);
 293   return true;
 294 }
 295
 296 File::Error base::File::Lock() {
 297   DCHECK(IsValid());
 298   BOOL result = LockFile(file_.Get(), 0, 0, MAXDWORD, MAXDWORD);
 299   if (!result)
 300     return OSErrorToFileError(GetLastError());
 301   return FILE_OK;
 302 }
 303
 304 File::Error File::Unlock() {
 305   DCHECK(IsValid());
 306   BOOL result = UnlockFile(file_.Get(), 0, 0, MAXDWORD, MAXDWORD);
 307   if (!result)
 308     return OSErrorToFileError(GetLastError());
 309   return FILE_OK;
 310 }
 311
 312 // Static.
 313 File::Error File::OSErrorToFileError(DWORD last_error) {
 314   switch (last_error) {
 315     case ERROR_SHARING_VIOLATION:
 316       return FILE_ERROR_IN_USE;
 317     case ERROR_FILE_EXISTS:
 318       return FILE_ERROR_EXISTS;
 319     case ERROR_FILE_NOT_FOUND:
 320     case ERROR_PATH_NOT_FOUND:
 321       return FILE_ERROR_NOT_FOUND;
 322     case ERROR_ACCESS_DENIED:
 323       return FILE_ERROR_ACCESS_DENIED;
 324     case ERROR_TOO_MANY_OPEN_FILES:
 325       return FILE_ERROR_TOO_MANY_OPENED;
 326     case ERROR_OUTOFMEMORY:
 327     case ERROR_NOT_ENOUGH_MEMORY:
 328       return FILE_ERROR_NO_MEMORY;
 329     case ERROR_HANDLE_DISK_FULL:
 330     case ERROR_DISK_FULL:
 331     case ERROR_DISK_RESOURCES_EXHAUSTED:
 332       return FILE_ERROR_NO_SPACE;
 333     case ERROR_USER_MAPPED_FILE:
 334       return FILE_ERROR_INVALID_OPERATION;
 335     case ERROR_NOT_READY:
 336     case ERROR_SECTOR_NOT_FOUND:
 337     case ERROR_DEV_NOT_EXIST:
 338     case ERROR_IO_DEVICE:
 339     case ERROR_FILE_CORRUPT:
 340     case ERROR_DISK_CORRUPT:
 341       return FILE_ERROR_IO;
 342     default:
 343       UMA_HISTOGRAM_SPARSE_SLOWLY("PlatformFile.UnknownErrors.Windows",
 344                                   last_error);
 345       return FILE_ERROR_FAILED;
 346   }
 347 }
 348
 349 void File::SetPlatformFile(PlatformFile file) {
 350   file_.Set(file);
 351 }
 352
 353 }  // namespace base