chrome/browser/media_galleries/win/mtp_device_delegate_impl_win.cc

   1 // Copyright (c) 2013 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 // MTPDeviceDelegateImplWin implementation.
   6
   7 #include "chrome/browser/media_galleries/win/mtp_device_delegate_impl_win.h"
   8
   9 #include <portabledevice.h>
  10
  11 #include <vector>
  12
  13 #include "base/bind.h"
  14 #include "base/files/file_path.h"
  15 #include "base/logging.h"
  16 #include "base/memory/ref_counted.h"
  17 #include "base/sequenced_task_runner.h"
  18 #include "base/stl_util.h"
  19 #include "base/strings/string_split.h"
  20 #include "base/strings/string_util.h"
  21 #include "base/strings/utf_string_conversions.h"
  22 #include "base/task_runner_util.h"
  23 #include "base/threading/thread_restrictions.h"
  24 #include "chrome/browser/media_galleries/fileapi/media_file_system_backend.h"
  25 #include "chrome/browser/media_galleries/win/mtp_device_object_entry.h"
  26 #include "chrome/browser/media_galleries/win/mtp_device_object_enumerator.h"
  27 #include "chrome/browser/media_galleries/win/mtp_device_operations_util.h"
  28 #include "chrome/browser/media_galleries/win/portable_device_map_service.h"
  29 #include "chrome/browser/media_galleries/win/snapshot_file_details.h"
  30 #include "components/storage_monitor/storage_monitor.h"
  31 #include "content/public/browser/browser_thread.h"
  32 #include "storage/common/fileapi/file_system_util.h"
  33
  34 namespace {
  35
  36 // Gets the details of the MTP partition storage specified by the
  37 // |storage_path| on the UI thread. Returns true if the storage details are
  38 // valid and returns false otherwise.
  39 bool GetStorageInfoOnUIThread(const base::string16& storage_path,
  40                               base::string16* pnp_device_id,
  41                               base::string16* storage_object_id) {
  42   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
  43   DCHECK(!storage_path.empty());
  44   DCHECK(pnp_device_id);
  45   DCHECK(storage_object_id);
  46   base::string16 storage_device_id;
  47   base::RemoveChars(storage_path, L"\\\\", &storage_device_id);
  48   DCHECK(!storage_device_id.empty());
  49   // TODO(gbillock): Take the StorageMonitor as an argument.
  50   storage_monitor::StorageMonitor* monitor =
  51       storage_monitor::StorageMonitor::GetInstance();
  52   DCHECK(monitor);
  53   return monitor->GetMTPStorageInfoFromDeviceId(
  54       base::UTF16ToUTF8(storage_device_id), pnp_device_id, storage_object_id);
  55 }
  56
  57 // Returns the object id of the file object specified by the |file_path|,
  58 // e.g. if the |file_path| is "\\MTP:StorageSerial:SID-{1001,,192}:125\DCIM"
  59 // and |device_info.registered_device_path_| is
  60 // "\\MTP:StorageSerial:SID-{1001,,192}:125", this function returns the
  61 // identifier of the "DCIM" folder object.
  62 //
  63 // Returns an empty string if the device is detached while the request is in
  64 // progress or when the |file_path| is invalid.
  65 base::string16 GetFileObjectIdFromPathOnBlockingPoolThread(
  66     const MTPDeviceDelegateImplWin::StorageDeviceInfo& device_info,
  67     const base::FilePath& file_path) {
  68   base::ThreadRestrictions::AssertIOAllowed();
  69   DCHECK(!file_path.empty());
  70   IPortableDevice* device =
  71       PortableDeviceMapService::GetInstance()->GetPortableDevice(
  72           device_info.registered_device_path);
  73   if (!device)
  74     return base::string16();
  75
  76   if (device_info.registered_device_path == file_path.value())
  77     return device_info.storage_object_id;
  78
  79   base::FilePath relative_path;
  80   if (!base::FilePath(device_info.registered_device_path).AppendRelativePath(
  81           file_path, &relative_path))
  82     return base::string16();
  83
  84   std::vector<base::string16> path_components;
  85   relative_path.GetComponents(&path_components);
  86   DCHECK(!path_components.empty());
  87   base::string16 parent_id(device_info.storage_object_id);
  88   base::string16 file_object_id;
  89   for (size_t i = 0; i < path_components.size(); ++i) {
  90     file_object_id =
  91         media_transfer_protocol::GetObjectIdFromName(device, parent_id,
  92                                                      path_components[i]);
  93     if (file_object_id.empty())
  94       break;
  95     parent_id = file_object_id;
  96   }
  97   return file_object_id;
  98 }
  99
 100 // Returns a pointer to a new instance of AbstractFileEnumerator for the given
 101 // |root| directory. Called on a blocking pool thread.
 102 scoped_ptr<MTPDeviceObjectEnumerator>
 103 CreateFileEnumeratorOnBlockingPoolThread(
 104     const MTPDeviceDelegateImplWin::StorageDeviceInfo& device_info,
 105     const base::FilePath& root) {
 106   base::ThreadRestrictions::AssertIOAllowed();
 107   DCHECK(!device_info.registered_device_path.empty());
 108   DCHECK(!root.empty());
 109   IPortableDevice* device =
 110       PortableDeviceMapService::GetInstance()->GetPortableDevice(
 111           device_info.registered_device_path);
 112   if (!device)
 113     return scoped_ptr<MTPDeviceObjectEnumerator>();
 114
 115   base::string16 object_id =
 116       GetFileObjectIdFromPathOnBlockingPoolThread(device_info, root);
 117   if (object_id.empty())
 118     return scoped_ptr<MTPDeviceObjectEnumerator>();
 119
 120   MTPDeviceObjectEntries entries;
 121   if (!media_transfer_protocol::GetDirectoryEntries(device, object_id,
 122                                                     &entries) ||
 123       entries.empty())
 124     return scoped_ptr<MTPDeviceObjectEnumerator>();
 125
 126   return scoped_ptr<MTPDeviceObjectEnumerator>(
 127       new MTPDeviceObjectEnumerator(entries));
 128 }
 129
 130 // Opens the device for communication on a blocking pool thread.
 131 // |pnp_device_id| specifies the PnP device id.
 132 // |registered_device_path| specifies the registered file system root path for
 133 // the given device.
 134 bool OpenDeviceOnBlockingPoolThread(
 135     const base::string16& pnp_device_id,
 136     const base::string16& registered_device_path) {
 137   base::ThreadRestrictions::AssertIOAllowed();
 138   DCHECK(!pnp_device_id.empty());
 139   DCHECK(!registered_device_path.empty());
 140   base::win::ScopedComPtr<IPortableDevice> device =
 141       media_transfer_protocol::OpenDevice(pnp_device_id);
 142   bool init_succeeded = device.get() != NULL;
 143   if (init_succeeded) {
 144     PortableDeviceMapService::GetInstance()->AddPortableDevice(
 145         registered_device_path, device.get());
 146   }
 147   return init_succeeded;
 148 }
 149
 150 // Gets the |file_path| details from the MTP device specified by the
 151 // |device_info.registered_device_path|. On success, |error| is set to
 152 // base::File::FILE_OK and fills in |file_info|. On failure, |error| is set
 153 // to corresponding platform file error and |file_info| is not set.
 154 base::File::Error GetFileInfoOnBlockingPoolThread(
 155     const MTPDeviceDelegateImplWin::StorageDeviceInfo& device_info,
 156     const base::FilePath& file_path,
 157     base::File::Info* file_info) {
 158   base::ThreadRestrictions::AssertIOAllowed();
 159   DCHECK(!device_info.registered_device_path.empty());
 160   DCHECK(!file_path.empty());
 161   DCHECK(file_info);
 162   IPortableDevice* device =
 163       PortableDeviceMapService::GetInstance()->GetPortableDevice(
 164           device_info.registered_device_path);
 165   if (!device)
 166     return base::File::FILE_ERROR_FAILED;
 167
 168   base::string16 object_id =
 169       GetFileObjectIdFromPathOnBlockingPoolThread(device_info, file_path);
 170   if (object_id.empty())
 171     return base::File::FILE_ERROR_FAILED;
 172   return media_transfer_protocol::GetFileEntryInfo(device, object_id,
 173                                                    file_info);
 174 }
 175
 176 // Reads the |root| directory file entries on a blocking pool thread. On
 177 // success, |error| is set to base::File::FILE_OK and |entries| contains the
 178 // directory file entries. On failure, |error| is set to platform file error
 179 // and |entries| is not set.
 180 base::File::Error ReadDirectoryOnBlockingPoolThread(
 181     const MTPDeviceDelegateImplWin::StorageDeviceInfo& device_info,
 182     const base::FilePath& root,
 183     storage::AsyncFileUtil::EntryList* entries) {
 184   base::ThreadRestrictions::AssertIOAllowed();
 185   DCHECK(!root.empty());
 186   DCHECK(entries);
 187   base::File::Info file_info;
 188   base::File::Error error = GetFileInfoOnBlockingPoolThread(device_info, root,
 189                                                             &file_info);
 190   if (error != base::File::FILE_OK)
 191     return error;
 192
 193   if (!file_info.is_directory)
 194     return base::File::FILE_ERROR_NOT_A_DIRECTORY;
 195
 196   base::FilePath current;
 197   scoped_ptr<MTPDeviceObjectEnumerator> file_enum =
 198       CreateFileEnumeratorOnBlockingPoolThread(device_info, root);
 199   if (!file_enum)
 200     return error;
 201
 202   while (!(current = file_enum->Next()).empty()) {
 203     storage::DirectoryEntry entry;
 204     entry.is_directory = file_enum->IsDirectory();
 205     entry.name = storage::VirtualPath::BaseName(current).value();
 206     entry.size = file_enum->Size();
 207     entry.last_modified_time = file_enum->LastModifiedTime();
 208     entries->push_back(entry);
 209   }
 210   return error;
 211 }
 212
 213 // Gets the device file stream object on a blocking pool thread.
 214 // |device_info| contains the device storage partition details.
 215 // On success, returns base::File::FILE_OK and file stream details are set in
 216 // |file_details|. On failure, returns a platform file error and file stream
 217 // details are not set in |file_details|.
 218 base::File::Error GetFileStreamOnBlockingPoolThread(
 219     const MTPDeviceDelegateImplWin::StorageDeviceInfo& device_info,
 220     SnapshotFileDetails* file_details) {
 221   base::ThreadRestrictions::AssertIOAllowed();
 222   DCHECK(file_details);
 223   DCHECK(!file_details->request_info().device_file_path.empty());
 224   DCHECK(!file_details->request_info().snapshot_file_path.empty());
 225   IPortableDevice* device =
 226       PortableDeviceMapService::GetInstance()->GetPortableDevice(
 227           device_info.registered_device_path);
 228   if (!device)
 229     return base::File::FILE_ERROR_FAILED;
 230
 231   base::string16 file_object_id =
 232       GetFileObjectIdFromPathOnBlockingPoolThread(
 233           device_info, file_details->request_info().device_file_path);
 234   if (file_object_id.empty())
 235     return base::File::FILE_ERROR_FAILED;
 236
 237   base::File::Info file_info;
 238   base::File::Error error =
 239       GetFileInfoOnBlockingPoolThread(
 240           device_info,
 241           file_details->request_info().device_file_path,
 242           &file_info);
 243   if (error != base::File::FILE_OK)
 244     return error;
 245
 246   DWORD optimal_transfer_size = 0;
 247   base::win::ScopedComPtr<IStream> file_stream;
 248   if (file_info.size > 0) {
 249     HRESULT hr = media_transfer_protocol::GetFileStreamForObject(
 250         device,
 251         file_object_id,
 252         file_stream.Receive(),
 253         &optimal_transfer_size);
 254     if (hr != S_OK)
 255       return base::File::FILE_ERROR_FAILED;
 256   }
 257
 258   // LocalFileStreamReader is used to read the contents of the snapshot file.
 259   // Snapshot file modification time does not match the last modified time
 260   // of the original media file. Therefore, set the last modified time to null
 261   // in order to avoid the verification in LocalFileStreamReader.
 262   //
 263   // Users will use HTML5 FileSystem Entry getMetadata() interface to get the
 264   // actual last modified time of the media file.
 265   file_info.last_modified = base::Time();
 266
 267   DCHECK(file_info.size == 0 || optimal_transfer_size > 0U);
 268   file_details->set_file_info(file_info);
 269   file_details->set_device_file_stream(file_stream.get());
 270   file_details->set_optimal_transfer_size(optimal_transfer_size);
 271   return error;
 272 }
 273
 274 // Copies the data chunk from device file to the snapshot file based on the
 275 // parameters specified by |file_details|.
 276 // Returns the total number of bytes written to the snapshot file for non-empty
 277 // files, or 0 on failure. For empty files, just return 0.
 278 DWORD WriteDataChunkIntoSnapshotFileOnBlockingPoolThread(
 279     const SnapshotFileDetails& file_details) {
 280   base::ThreadRestrictions::AssertIOAllowed();
 281   if (file_details.file_info().size == 0)
 282     return 0;
 283   return media_transfer_protocol::CopyDataChunkToLocalFile(
 284       file_details.device_file_stream(),
 285       file_details.request_info().snapshot_file_path,
 286       file_details.optimal_transfer_size());
 287 }
 288
 289 void DeletePortableDeviceOnBlockingPoolThread(
 290     const base::string16& registered_device_path) {
 291   base::ThreadRestrictions::AssertIOAllowed();
 292   PortableDeviceMapService::GetInstance()->RemovePortableDevice(
 293       registered_device_path);
 294 }
 295
 296 }  // namespace
 297
 298 // Used by CreateMTPDeviceAsyncDelegate() to create the MTP device
 299 // delegate on the IO thread.
 300 void OnGetStorageInfoCreateDelegate(
 301     const base::string16& device_location,
 302     const CreateMTPDeviceAsyncDelegateCallback& callback,
 303     base::string16* pnp_device_id,
 304     base::string16* storage_object_id,
 305     bool succeeded) {
 306   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 307   DCHECK(pnp_device_id);
 308   DCHECK(storage_object_id);
 309   if (!succeeded)
 310     return;
 311   callback.Run(new MTPDeviceDelegateImplWin(device_location,
 312                                             *pnp_device_id,
 313                                             *storage_object_id));
 314 }
 315
 316 void CreateMTPDeviceAsyncDelegate(
 317     const base::string16& device_location,
 318     const bool read_only,
 319     const CreateMTPDeviceAsyncDelegateCallback& callback) {
 320   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 321
 322   // Write operation is not supported on Windows.
 323   DCHECK(read_only);
 324
 325   DCHECK(!device_location.empty());
 326   base::string16* pnp_device_id = new base::string16;
 327   base::string16* storage_object_id = new base::string16;
 328   content::BrowserThread::PostTaskAndReplyWithResult<bool>(
 329       content::BrowserThread::UI,
 330       FROM_HERE,
 331       base::Bind(&GetStorageInfoOnUIThread,
 332                  device_location,
 333                  base::Unretained(pnp_device_id),
 334                  base::Unretained(storage_object_id)),
 335       base::Bind(&OnGetStorageInfoCreateDelegate,
 336                  device_location,
 337                  callback,
 338                  base::Owned(pnp_device_id),
 339                  base::Owned(storage_object_id)));
 340 }
 341
 342 // MTPDeviceDelegateImplWin ---------------------------------------------------
 343
 344 MTPDeviceDelegateImplWin::StorageDeviceInfo::StorageDeviceInfo(
 345     const base::string16& pnp_device_id,
 346     const base::string16& registered_device_path,
 347     const base::string16& storage_object_id)
 348     : pnp_device_id(pnp_device_id),
 349       registered_device_path(registered_device_path),
 350       storage_object_id(storage_object_id) {
 351   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 352 }
 353
 354 MTPDeviceDelegateImplWin::PendingTaskInfo::PendingTaskInfo(
 355     const tracked_objects::Location& location,
 356     const base::Callback<base::File::Error(void)>& task,
 357     const base::Callback<void(base::File::Error)>& reply)
 358     : location(location),
 359       task(task),
 360       reply(reply) {
 361 }
 362
 363 MTPDeviceDelegateImplWin::MTPDeviceDelegateImplWin(
 364     const base::string16& registered_device_path,
 365     const base::string16& pnp_device_id,
 366     const base::string16& storage_object_id)
 367     : storage_device_info_(pnp_device_id, registered_device_path,
 368                            storage_object_id),
 369       init_state_(UNINITIALIZED),
 370       media_task_runner_(MediaFileSystemBackend::MediaTaskRunner()),
 371       task_in_progress_(false),
 372       weak_ptr_factory_(this) {
 373   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 374   DCHECK(!registered_device_path.empty());
 375   DCHECK(!pnp_device_id.empty());
 376   DCHECK(!storage_object_id.empty());
 377   DCHECK(media_task_runner_.get());
 378 }
 379
 380 MTPDeviceDelegateImplWin::~MTPDeviceDelegateImplWin() {
 381   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 382 }
 383
 384 void MTPDeviceDelegateImplWin::GetFileInfo(
 385     const base::FilePath& file_path,
 386     const GetFileInfoSuccessCallback& success_callback,
 387     const ErrorCallback& error_callback) {
 388   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 389   DCHECK(!file_path.empty());
 390   base::File::Info* file_info = new base::File::Info;
 391   EnsureInitAndRunTask(
 392       PendingTaskInfo(FROM_HERE,
 393                       base::Bind(&GetFileInfoOnBlockingPoolThread,
 394                                  storage_device_info_,
 395                                  file_path,
 396                                  base::Unretained(file_info)),
 397                       base::Bind(&MTPDeviceDelegateImplWin::OnGetFileInfo,
 398                                  weak_ptr_factory_.GetWeakPtr(),
 399                                  success_callback,
 400                                  error_callback,
 401                                  base::Owned(file_info))));
 402 }
 403
 404 void MTPDeviceDelegateImplWin::CreateDirectory(
 405     const base::FilePath& directory_path,
 406     const bool exclusive,
 407     const bool recursive,
 408     const CreateDirectorySuccessCallback& success_callback,
 409     const ErrorCallback& error_callback) {
 410   NOTREACHED();
 411 }
 412
 413 void MTPDeviceDelegateImplWin::ReadDirectory(
 414     const base::FilePath& root,
 415     const ReadDirectorySuccessCallback& success_callback,
 416     const ErrorCallback& error_callback) {
 417   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 418   DCHECK(!root.empty());
 419   storage::AsyncFileUtil::EntryList* entries =
 420       new storage::AsyncFileUtil::EntryList;
 421   EnsureInitAndRunTask(
 422       PendingTaskInfo(FROM_HERE,
 423                       base::Bind(&ReadDirectoryOnBlockingPoolThread,
 424                                  storage_device_info_,
 425                                  root,
 426                                  base::Unretained(entries)),
 427                       base::Bind(&MTPDeviceDelegateImplWin::OnDidReadDirectory,
 428                                  weak_ptr_factory_.GetWeakPtr(),
 429                                  success_callback,
 430                                  error_callback,
 431                                  base::Owned(entries))));
 432 }
 433
 434 void MTPDeviceDelegateImplWin::CreateSnapshotFile(
 435     const base::FilePath& device_file_path,
 436     const base::FilePath& snapshot_file_path,
 437     const CreateSnapshotFileSuccessCallback& success_callback,
 438     const ErrorCallback& error_callback) {
 439   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 440   DCHECK(!device_file_path.empty());
 441   DCHECK(!snapshot_file_path.empty());
 442   scoped_ptr<SnapshotFileDetails> file_details(
 443       new SnapshotFileDetails(SnapshotRequestInfo(device_file_path,
 444                                                   snapshot_file_path,
 445                                                   success_callback,
 446                                                   error_callback)));
 447   // Passing a raw SnapshotFileDetails* to the blocking pool is safe, because
 448   // it is owned by |file_details| in the reply callback.
 449   EnsureInitAndRunTask(
 450       PendingTaskInfo(FROM_HERE,
 451                       base::Bind(&GetFileStreamOnBlockingPoolThread,
 452                                  storage_device_info_,
 453                                  file_details.get()),
 454                       base::Bind(&MTPDeviceDelegateImplWin::OnGetFileStream,
 455                                  weak_ptr_factory_.GetWeakPtr(),
 456                                  base::Passed(&file_details))));
 457 }
 458
 459 bool MTPDeviceDelegateImplWin::IsStreaming() {
 460   return false;
 461 }
 462
 463 void MTPDeviceDelegateImplWin::ReadBytes(
 464     const base::FilePath& device_file_path,
 465     const scoped_refptr<net::IOBuffer>& buf,
 466     int64 offset,
 467     int buf_len,
 468     const ReadBytesSuccessCallback& success_callback,
 469     const ErrorCallback& error_callback) {
 470   NOTREACHED();
 471 }
 472
 473 bool MTPDeviceDelegateImplWin::IsReadOnly() const {
 474   return true;
 475 }
 476
 477 void MTPDeviceDelegateImplWin::CopyFileLocal(
 478     const base::FilePath& source_file_path,
 479     const base::FilePath& device_file_path,
 480     const CreateTemporaryFileCallback& create_temporary_file_callback,
 481     const CopyFileProgressCallback& progress_callback,
 482     const CopyFileLocalSuccessCallback& success_callback,
 483     const ErrorCallback& error_callback) {
 484   NOTREACHED();
 485 }
 486
 487 void MTPDeviceDelegateImplWin::MoveFileLocal(
 488     const base::FilePath& source_file_path,
 489     const base::FilePath& device_file_path,
 490     const CreateTemporaryFileCallback& create_temporary_file_callback,
 491     const MoveFileLocalSuccessCallback& success_callback,
 492     const ErrorCallback& error_callback) {
 493   NOTREACHED();
 494 }
 495
 496 void MTPDeviceDelegateImplWin::CopyFileFromLocal(
 497     const base::FilePath& source_file_path,
 498     const base::FilePath& device_file_path,
 499     const CopyFileFromLocalSuccessCallback& success_callback,
 500     const ErrorCallback& error_callback) {
 501   NOTREACHED();
 502 }
 503
 504 void MTPDeviceDelegateImplWin::DeleteFile(
 505     const base::FilePath& file_path,
 506     const DeleteFileSuccessCallback& success_callback,
 507     const ErrorCallback& error_callback) {
 508   NOTREACHED();
 509 }
 510
 511 void MTPDeviceDelegateImplWin::DeleteDirectory(
 512     const base::FilePath& file_path,
 513     const DeleteDirectorySuccessCallback& success_callback,
 514     const ErrorCallback& error_callback) {
 515   NOTREACHED();
 516 }
 517
 518 void MTPDeviceDelegateImplWin::CancelPendingTasksAndDeleteDelegate() {
 519   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 520   PortableDeviceMapService::GetInstance()->MarkPortableDeviceForDeletion(
 521       storage_device_info_.registered_device_path);
 522   media_task_runner_->PostTask(
 523       FROM_HERE,
 524       base::Bind(&DeletePortableDeviceOnBlockingPoolThread,
 525                  storage_device_info_.registered_device_path));
 526   while (!pending_tasks_.empty())
 527     pending_tasks_.pop();
 528   delete this;
 529 }
 530
 531 void MTPDeviceDelegateImplWin::EnsureInitAndRunTask(
 532     const PendingTaskInfo& task_info) {
 533   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 534   if ((init_state_ == INITIALIZED) && !task_in_progress_) {
 535     DCHECK(pending_tasks_.empty());
 536     DCHECK(!current_snapshot_details_.get());
 537     base::PostTaskAndReplyWithResult(media_task_runner_.get(),
 538                                      task_info.location, task_info.task,
 539                                      task_info.reply);
 540     task_in_progress_ = true;
 541     return;
 542   }
 543
 544   pending_tasks_.push(task_info);
 545   if (init_state_ == UNINITIALIZED) {
 546     init_state_ = PENDING_INIT;
 547     base::PostTaskAndReplyWithResult(
 548         media_task_runner_.get(), FROM_HERE,
 549         base::Bind(&OpenDeviceOnBlockingPoolThread,
 550                    storage_device_info_.pnp_device_id,
 551                    storage_device_info_.registered_device_path),
 552         base::Bind(&MTPDeviceDelegateImplWin::OnInitCompleted,
 553                    weak_ptr_factory_.GetWeakPtr()));
 554     task_in_progress_ = true;
 555   }
 556 }
 557
 558 void MTPDeviceDelegateImplWin::WriteDataChunkIntoSnapshotFile() {
 559   DCHECK(current_snapshot_details_.get());
 560   base::PostTaskAndReplyWithResult(
 561       media_task_runner_.get(), FROM_HERE,
 562       base::Bind(&WriteDataChunkIntoSnapshotFileOnBlockingPoolThread,
 563                  *current_snapshot_details_),
 564       base::Bind(&MTPDeviceDelegateImplWin::OnWroteDataChunkIntoSnapshotFile,
 565                  weak_ptr_factory_.GetWeakPtr(),
 566                  current_snapshot_details_->request_info().snapshot_file_path));
 567 }
 568
 569 void MTPDeviceDelegateImplWin::ProcessNextPendingRequest() {
 570   DCHECK(!task_in_progress_);
 571   if (pending_tasks_.empty())
 572     return;
 573   const PendingTaskInfo& task_info = pending_tasks_.front();
 574   task_in_progress_ = true;
 575   base::PostTaskAndReplyWithResult(media_task_runner_.get(), task_info.location,
 576                                    task_info.task, task_info.reply);
 577   pending_tasks_.pop();
 578 }
 579
 580 void MTPDeviceDelegateImplWin::OnInitCompleted(bool succeeded) {
 581   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 582   init_state_ = succeeded ? INITIALIZED : UNINITIALIZED;
 583   task_in_progress_ = false;
 584   ProcessNextPendingRequest();
 585 }
 586
 587 void MTPDeviceDelegateImplWin::OnGetFileInfo(
 588     const GetFileInfoSuccessCallback& success_callback,
 589     const ErrorCallback& error_callback,
 590     base::File::Info* file_info,
 591     base::File::Error error) {
 592   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 593   DCHECK(file_info);
 594   if (error == base::File::FILE_OK)
 595     success_callback.Run(*file_info);
 596   else
 597     error_callback.Run(error);
 598   task_in_progress_ = false;
 599   ProcessNextPendingRequest();
 600 }
 601
 602 void MTPDeviceDelegateImplWin::OnDidReadDirectory(
 603     const ReadDirectorySuccessCallback& success_callback,
 604     const ErrorCallback& error_callback,
 605     storage::AsyncFileUtil::EntryList* file_list,
 606     base::File::Error error) {
 607   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 608   DCHECK(file_list);
 609   if (error == base::File::FILE_OK)
 610     success_callback.Run(*file_list, false /*no more entries*/);
 611   else
 612     error_callback.Run(error);
 613   task_in_progress_ = false;
 614   ProcessNextPendingRequest();
 615 }
 616
 617 void MTPDeviceDelegateImplWin::OnGetFileStream(
 618     scoped_ptr<SnapshotFileDetails> file_details,
 619     base::File::Error error) {
 620   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 621   DCHECK(file_details);
 622   DCHECK(!file_details->request_info().device_file_path.empty());
 623   DCHECK(!file_details->request_info().snapshot_file_path.empty());
 624   DCHECK(!current_snapshot_details_.get());
 625   if (error != base::File::FILE_OK) {
 626     file_details->request_info().error_callback.Run(error);
 627     task_in_progress_ = false;
 628     ProcessNextPendingRequest();
 629     return;
 630   }
 631   DCHECK(file_details->file_info().size == 0 ||
 632          file_details->device_file_stream());
 633   current_snapshot_details_.reset(file_details.release());
 634   WriteDataChunkIntoSnapshotFile();
 635 }
 636
 637 void MTPDeviceDelegateImplWin::OnWroteDataChunkIntoSnapshotFile(
 638     const base::FilePath& snapshot_file_path,
 639     DWORD bytes_written) {
 640   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
 641   DCHECK(!snapshot_file_path.empty());
 642   if (!current_snapshot_details_.get())
 643     return;
 644   DCHECK_EQ(
 645       current_snapshot_details_->request_info().snapshot_file_path.value(),
 646       snapshot_file_path.value());
 647
 648   bool succeeded = false;
 649   bool should_continue = false;
 650   if (current_snapshot_details_->file_info().size > 0) {
 651     if (current_snapshot_details_->AddBytesWritten(bytes_written)) {
 652       if (current_snapshot_details_->IsSnapshotFileWriteComplete()) {
 653         succeeded = true;
 654       } else {
 655         should_continue = true;
 656       }
 657     }
 658   } else {
 659     // Handle empty files.
 660     DCHECK_EQ(0U, bytes_written);
 661     succeeded = true;
 662   }
 663
 664   if (should_continue) {
 665     WriteDataChunkIntoSnapshotFile();
 666     return;
 667   }
 668   if (succeeded) {
 669     current_snapshot_details_->request_info().success_callback.Run(
 670         current_snapshot_details_->file_info(),
 671         current_snapshot_details_->request_info().snapshot_file_path);
 672   } else {
 673     current_snapshot_details_->request_info().error_callback.Run(
 674         base::File::FILE_ERROR_FAILED);
 675   }
 676   task_in_progress_ = false;
 677   current_snapshot_details_.reset();
 678   ProcessNextPendingRequest();
 679 }