Home | History | Annotate | Download | only in win
      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 "chrome/browser/storage_monitor/storage_monitor.h"
     31 #include "content/public/browser/browser_thread.h"
     32 #include "webkit/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(content::BrowserThread::CurrentlyOn(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   StorageMonitor* monitor = StorageMonitor::GetInstance();
     51   DCHECK(monitor);
     52   return monitor->GetMTPStorageInfoFromDeviceId(
     53       UTF16ToUTF8(storage_device_id), pnp_device_id, storage_object_id);
     54 }
     55 
     56 // Returns the object id of the file object specified by the |file_path|,
     57 // e.g. if the |file_path| is "\\MTP:StorageSerial:SID-{1001,,192}:125\DCIM"
     58 // and |device_info.registered_device_path_| is
     59 // "\\MTP:StorageSerial:SID-{1001,,192}:125", this function returns the
     60 // identifier of the "DCIM" folder object.
     61 //
     62 // Returns an empty string if the device is detached while the request is in
     63 // progress or when the |file_path| is invalid.
     64 base::string16 GetFileObjectIdFromPathOnBlockingPoolThread(
     65     const MTPDeviceDelegateImplWin::StorageDeviceInfo& device_info,
     66     const base::FilePath& file_path) {
     67   base::ThreadRestrictions::AssertIOAllowed();
     68   DCHECK(!file_path.empty());
     69   IPortableDevice* device =
     70       PortableDeviceMapService::GetInstance()->GetPortableDevice(
     71           device_info.registered_device_path);
     72   if (!device)
     73     return base::string16();
     74 
     75   if (device_info.registered_device_path == file_path.value())
     76     return device_info.storage_object_id;
     77 
     78   base::FilePath relative_path;
     79   if (!base::FilePath(device_info.registered_device_path).AppendRelativePath(
     80           file_path, &relative_path))
     81     return base::string16();
     82 
     83   std::vector<base::string16> path_components;
     84   relative_path.GetComponents(&path_components);
     85   DCHECK(!path_components.empty());
     86   base::string16 parent_id(device_info.storage_object_id);
     87   base::string16 file_object_id;
     88   for (size_t i = 0; i < path_components.size(); ++i) {
     89     file_object_id =
     90         media_transfer_protocol::GetObjectIdFromName(device, parent_id,
     91                                                      path_components[i]);
     92     if (file_object_id.empty())
     93       break;
     94     parent_id = file_object_id;
     95   }
     96   return file_object_id;
     97 }
     98 
     99 // Returns a pointer to a new instance of AbstractFileEnumerator for the given
    100 // |root| directory. Called on a blocking pool thread.
    101 scoped_ptr<MTPDeviceObjectEnumerator>
    102 CreateFileEnumeratorOnBlockingPoolThread(
    103     const MTPDeviceDelegateImplWin::StorageDeviceInfo& device_info,
    104     const base::FilePath& root) {
    105   base::ThreadRestrictions::AssertIOAllowed();
    106   DCHECK(!device_info.registered_device_path.empty());
    107   DCHECK(!root.empty());
    108   IPortableDevice* device =
    109       PortableDeviceMapService::GetInstance()->GetPortableDevice(
    110           device_info.registered_device_path);
    111   if (!device)
    112     return scoped_ptr<MTPDeviceObjectEnumerator>();
    113 
    114   base::string16 object_id =
    115       GetFileObjectIdFromPathOnBlockingPoolThread(device_info, root);
    116   if (object_id.empty())
    117     return scoped_ptr<MTPDeviceObjectEnumerator>();
    118 
    119   MTPDeviceObjectEntries entries;
    120   if (!media_transfer_protocol::GetDirectoryEntries(device, object_id,
    121                                                     &entries) ||
    122       entries.empty())
    123     return scoped_ptr<MTPDeviceObjectEnumerator>();
    124 
    125   return scoped_ptr<MTPDeviceObjectEnumerator>(
    126       new MTPDeviceObjectEnumerator(entries));
    127 }
    128 
    129 // Opens the device for communication on a blocking pool thread.
    130 // |pnp_device_id| specifies the PnP device id.
    131 // |registered_device_path| specifies the registered file system root path for
    132 // the given device.
    133 bool OpenDeviceOnBlockingPoolThread(
    134     const base::string16& pnp_device_id,
    135     const base::string16& registered_device_path) {
    136   base::ThreadRestrictions::AssertIOAllowed();
    137   DCHECK(!pnp_device_id.empty());
    138   DCHECK(!registered_device_path.empty());
    139   base::win::ScopedComPtr<IPortableDevice> device =
    140       media_transfer_protocol::OpenDevice(pnp_device_id);
    141   bool init_succeeded = device.get() != NULL;
    142   if (init_succeeded) {
    143     PortableDeviceMapService::GetInstance()->AddPortableDevice(
    144         registered_device_path, device.get());
    145   }
    146   return init_succeeded;
    147 }
    148 
    149 // Gets the |file_path| details from the MTP device specified by the
    150 // |device_info.registered_device_path|. On success, |error| is set to
    151 // base::PLATFORM_FILE_OK and fills in |file_info|. On failure, |error| is set
    152 // to corresponding platform file error and |file_info| is not set.
    153 base::PlatformFileError GetFileInfoOnBlockingPoolThread(
    154     const MTPDeviceDelegateImplWin::StorageDeviceInfo& device_info,
    155     const base::FilePath& file_path,
    156     base::PlatformFileInfo* file_info) {
    157   base::ThreadRestrictions::AssertIOAllowed();
    158   DCHECK(!device_info.registered_device_path.empty());
    159   DCHECK(!file_path.empty());
    160   DCHECK(file_info);
    161   IPortableDevice* device =
    162       PortableDeviceMapService::GetInstance()->GetPortableDevice(
    163           device_info.registered_device_path);
    164   if (!device)
    165     return base::PLATFORM_FILE_ERROR_FAILED;
    166 
    167   base::string16 object_id =
    168       GetFileObjectIdFromPathOnBlockingPoolThread(device_info, file_path);
    169   if (object_id.empty())
    170     return base::PLATFORM_FILE_ERROR_FAILED;
    171   return media_transfer_protocol::GetFileEntryInfo(device, object_id,
    172                                                    file_info);
    173 }
    174 
    175 // Reads the |root| directory file entries on a blocking pool thread. On
    176 // success, |error| is set to base::PLATFORM_FILE_OK and |entries| contains the
    177 // directory file entries. On failure, |error| is set to platform file error
    178 // and |entries| is not set.
    179 base::PlatformFileError ReadDirectoryOnBlockingPoolThread(
    180     const MTPDeviceDelegateImplWin::StorageDeviceInfo& device_info,
    181     const base::FilePath& root,
    182     fileapi::AsyncFileUtil::EntryList* entries) {
    183   base::ThreadRestrictions::AssertIOAllowed();
    184   DCHECK(!root.empty());
    185   DCHECK(entries);
    186   base::PlatformFileInfo file_info;
    187   base::PlatformFileError error = GetFileInfoOnBlockingPoolThread(device_info,
    188                                                                   root,
    189                                                                   &file_info);
    190   if (error != base::PLATFORM_FILE_OK)
    191     return error;
    192 
    193   if (!file_info.is_directory)
    194     return base::PLATFORM_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     fileapi::DirectoryEntry entry;
    204     entry.is_directory = file_enum->IsDirectory();
    205     entry.name = fileapi::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::PLATFORM_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::PlatformFileError 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::PLATFORM_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::PLATFORM_FILE_ERROR_FAILED;
    236 
    237   base::PlatformFileInfo file_info;
    238   base::PlatformFileError error =
    239       GetFileInfoOnBlockingPoolThread(
    240           device_info,
    241           file_details->request_info().device_file_path,
    242           &file_info);
    243   if (error != base::PLATFORM_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::PLATFORM_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);
    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(content::BrowserThread::CurrentlyOn(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 CreateMTPDeviceAsyncDelegateCallback& callback) {
    319   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    320   DCHECK(!device_location.empty());
    321   base::string16* pnp_device_id = new base::string16;
    322   base::string16* storage_object_id = new base::string16;
    323   content::BrowserThread::PostTaskAndReplyWithResult<bool>(
    324       content::BrowserThread::UI,
    325       FROM_HERE,
    326       base::Bind(&GetStorageInfoOnUIThread,
    327                  device_location,
    328                  base::Unretained(pnp_device_id),
    329                  base::Unretained(storage_object_id)),
    330       base::Bind(&OnGetStorageInfoCreateDelegate,
    331                  device_location,
    332                  callback,
    333                  base::Owned(pnp_device_id),
    334                  base::Owned(storage_object_id)));
    335 }
    336 
    337 // MTPDeviceDelegateImplWin ---------------------------------------------------
    338 
    339 MTPDeviceDelegateImplWin::StorageDeviceInfo::StorageDeviceInfo(
    340     const base::string16& pnp_device_id,
    341     const base::string16& registered_device_path,
    342     const base::string16& storage_object_id)
    343     : pnp_device_id(pnp_device_id),
    344       registered_device_path(registered_device_path),
    345       storage_object_id(storage_object_id) {
    346   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    347 }
    348 
    349 MTPDeviceDelegateImplWin::PendingTaskInfo::PendingTaskInfo(
    350     const tracked_objects::Location& location,
    351     const base::Callback<base::PlatformFileError(void)>& task,
    352     const base::Callback<void(base::PlatformFileError)>& reply)
    353     : location(location),
    354       task(task),
    355       reply(reply) {
    356 }
    357 
    358 MTPDeviceDelegateImplWin::MTPDeviceDelegateImplWin(
    359     const base::string16& registered_device_path,
    360     const base::string16& pnp_device_id,
    361     const base::string16& storage_object_id)
    362     : storage_device_info_(pnp_device_id, registered_device_path,
    363                            storage_object_id),
    364       init_state_(UNINITIALIZED),
    365       media_task_runner_(MediaFileSystemBackend::MediaTaskRunner()),
    366       task_in_progress_(false),
    367       weak_ptr_factory_(this) {
    368   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    369   DCHECK(!registered_device_path.empty());
    370   DCHECK(!pnp_device_id.empty());
    371   DCHECK(!storage_object_id.empty());
    372   DCHECK(media_task_runner_.get());
    373 }
    374 
    375 MTPDeviceDelegateImplWin::~MTPDeviceDelegateImplWin() {
    376   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    377 }
    378 
    379 void MTPDeviceDelegateImplWin::GetFileInfo(
    380     const base::FilePath& file_path,
    381     const GetFileInfoSuccessCallback& success_callback,
    382     const ErrorCallback& error_callback) {
    383   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    384   DCHECK(!file_path.empty());
    385   base::PlatformFileInfo* file_info = new base::PlatformFileInfo;
    386   EnsureInitAndRunTask(
    387       PendingTaskInfo(FROM_HERE,
    388                       base::Bind(&GetFileInfoOnBlockingPoolThread,
    389                                  storage_device_info_,
    390                                  file_path,
    391                                  base::Unretained(file_info)),
    392                       base::Bind(&MTPDeviceDelegateImplWin::OnGetFileInfo,
    393                                  weak_ptr_factory_.GetWeakPtr(),
    394                                  success_callback,
    395                                  error_callback,
    396                                  base::Owned(file_info))));
    397 }
    398 
    399 void MTPDeviceDelegateImplWin::ReadDirectory(
    400     const base::FilePath& root,
    401     const ReadDirectorySuccessCallback& success_callback,
    402     const ErrorCallback& error_callback) {
    403   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    404   DCHECK(!root.empty());
    405   fileapi::AsyncFileUtil::EntryList* entries =
    406       new fileapi::AsyncFileUtil::EntryList;
    407   EnsureInitAndRunTask(
    408       PendingTaskInfo(FROM_HERE,
    409                       base::Bind(&ReadDirectoryOnBlockingPoolThread,
    410                                  storage_device_info_,
    411                                  root,
    412                                  base::Unretained(entries)),
    413                       base::Bind(&MTPDeviceDelegateImplWin::OnDidReadDirectory,
    414                                  weak_ptr_factory_.GetWeakPtr(),
    415                                  success_callback,
    416                                  error_callback,
    417                                  base::Owned(entries))));
    418 }
    419 
    420 void MTPDeviceDelegateImplWin::CreateSnapshotFile(
    421     const base::FilePath& device_file_path,
    422     const base::FilePath& snapshot_file_path,
    423     const CreateSnapshotFileSuccessCallback& success_callback,
    424     const ErrorCallback& error_callback) {
    425   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    426   DCHECK(!device_file_path.empty());
    427   DCHECK(!snapshot_file_path.empty());
    428   scoped_ptr<SnapshotFileDetails> file_details(
    429       new SnapshotFileDetails(SnapshotRequestInfo(device_file_path,
    430                                                   snapshot_file_path,
    431                                                   success_callback,
    432                                                   error_callback)));
    433   // Passing a raw SnapshotFileDetails* to the blocking pool is safe, because
    434   // it is owned by |file_details| in the reply callback.
    435   EnsureInitAndRunTask(
    436       PendingTaskInfo(FROM_HERE,
    437                       base::Bind(&GetFileStreamOnBlockingPoolThread,
    438                                  storage_device_info_,
    439                                  file_details.get()),
    440                       base::Bind(&MTPDeviceDelegateImplWin::OnGetFileStream,
    441                                  weak_ptr_factory_.GetWeakPtr(),
    442                                  base::Passed(&file_details))));
    443 }
    444 
    445 void MTPDeviceDelegateImplWin::CancelPendingTasksAndDeleteDelegate() {
    446   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    447   PortableDeviceMapService::GetInstance()->MarkPortableDeviceForDeletion(
    448       storage_device_info_.registered_device_path);
    449   media_task_runner_->PostTask(
    450       FROM_HERE,
    451       base::Bind(&DeletePortableDeviceOnBlockingPoolThread,
    452                  storage_device_info_.registered_device_path));
    453   while (!pending_tasks_.empty())
    454     pending_tasks_.pop();
    455   delete this;
    456 }
    457 
    458 void MTPDeviceDelegateImplWin::EnsureInitAndRunTask(
    459     const PendingTaskInfo& task_info) {
    460   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    461   if ((init_state_ == INITIALIZED) && !task_in_progress_) {
    462     DCHECK(pending_tasks_.empty());
    463     DCHECK(!current_snapshot_details_.get());
    464     base::PostTaskAndReplyWithResult(media_task_runner_,
    465                                      task_info.location,
    466                                      task_info.task,
    467                                      task_info.reply);
    468     task_in_progress_ = true;
    469     return;
    470   }
    471 
    472   pending_tasks_.push(task_info);
    473   if (init_state_ == UNINITIALIZED) {
    474     init_state_ = PENDING_INIT;
    475     base::PostTaskAndReplyWithResult(
    476         media_task_runner_,
    477         FROM_HERE,
    478         base::Bind(&OpenDeviceOnBlockingPoolThread,
    479                    storage_device_info_.pnp_device_id,
    480                    storage_device_info_.registered_device_path),
    481         base::Bind(&MTPDeviceDelegateImplWin::OnInitCompleted,
    482                    weak_ptr_factory_.GetWeakPtr()));
    483     task_in_progress_ = true;
    484   }
    485 }
    486 
    487 void MTPDeviceDelegateImplWin::WriteDataChunkIntoSnapshotFile() {
    488   DCHECK(current_snapshot_details_.get());
    489   base::PostTaskAndReplyWithResult(
    490       media_task_runner_,
    491       FROM_HERE,
    492       base::Bind(&WriteDataChunkIntoSnapshotFileOnBlockingPoolThread,
    493                  *current_snapshot_details_),
    494       base::Bind(&MTPDeviceDelegateImplWin::OnWroteDataChunkIntoSnapshotFile,
    495                  weak_ptr_factory_.GetWeakPtr(),
    496                  current_snapshot_details_->request_info().snapshot_file_path));
    497 }
    498 
    499 void MTPDeviceDelegateImplWin::ProcessNextPendingRequest() {
    500   DCHECK(!task_in_progress_);
    501   if (pending_tasks_.empty())
    502     return;
    503   const PendingTaskInfo& task_info = pending_tasks_.front();
    504   task_in_progress_ = true;
    505   base::PostTaskAndReplyWithResult(media_task_runner_,
    506                                    task_info.location,
    507                                    task_info.task,
    508                                    task_info.reply);
    509   pending_tasks_.pop();
    510 }
    511 
    512 void MTPDeviceDelegateImplWin::OnInitCompleted(bool succeeded) {
    513   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    514   init_state_ = succeeded ? INITIALIZED : UNINITIALIZED;
    515   task_in_progress_ = false;
    516   ProcessNextPendingRequest();
    517 }
    518 
    519 void MTPDeviceDelegateImplWin::OnGetFileInfo(
    520     const GetFileInfoSuccessCallback& success_callback,
    521     const ErrorCallback& error_callback,
    522     base::PlatformFileInfo* file_info,
    523     base::PlatformFileError error) {
    524   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    525   DCHECK(file_info);
    526   if (error == base::PLATFORM_FILE_OK)
    527     success_callback.Run(*file_info);
    528   else
    529     error_callback.Run(error);
    530   task_in_progress_ = false;
    531   ProcessNextPendingRequest();
    532 }
    533 
    534 void MTPDeviceDelegateImplWin::OnDidReadDirectory(
    535     const ReadDirectorySuccessCallback& success_callback,
    536     const ErrorCallback& error_callback,
    537     fileapi::AsyncFileUtil::EntryList* file_list,
    538     base::PlatformFileError error) {
    539   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    540   DCHECK(file_list);
    541   if (error == base::PLATFORM_FILE_OK)
    542     success_callback.Run(*file_list, false /*no more entries*/);
    543   else
    544     error_callback.Run(error);
    545   task_in_progress_ = false;
    546   ProcessNextPendingRequest();
    547 }
    548 
    549 void MTPDeviceDelegateImplWin::OnGetFileStream(
    550     scoped_ptr<SnapshotFileDetails> file_details,
    551     base::PlatformFileError error) {
    552   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    553   DCHECK(file_details);
    554   DCHECK(!file_details->request_info().device_file_path.empty());
    555   DCHECK(!file_details->request_info().snapshot_file_path.empty());
    556   DCHECK(!current_snapshot_details_.get());
    557   if (error != base::PLATFORM_FILE_OK) {
    558     file_details->request_info().error_callback.Run(error);
    559     task_in_progress_ = false;
    560     ProcessNextPendingRequest();
    561     return;
    562   }
    563   DCHECK(file_details->file_info().size == 0 ||
    564          file_details->device_file_stream());
    565   current_snapshot_details_.reset(file_details.release());
    566   WriteDataChunkIntoSnapshotFile();
    567 }
    568 
    569 void MTPDeviceDelegateImplWin::OnWroteDataChunkIntoSnapshotFile(
    570     const base::FilePath& snapshot_file_path,
    571     DWORD bytes_written) {
    572   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
    573   DCHECK(!snapshot_file_path.empty());
    574   if (!current_snapshot_details_.get())
    575     return;
    576   DCHECK_EQ(
    577       current_snapshot_details_->request_info().snapshot_file_path.value(),
    578       snapshot_file_path.value());
    579 
    580   bool succeeded = false;
    581   bool should_continue = false;
    582   if (current_snapshot_details_->file_info().size > 0) {
    583     if (current_snapshot_details_->AddBytesWritten(bytes_written)) {
    584       if (current_snapshot_details_->IsSnapshotFileWriteComplete()) {
    585         succeeded = true;
    586       } else {
    587         should_continue = true;
    588       }
    589     }
    590   } else {
    591     // Handle empty files.
    592     DCHECK_EQ(0U, bytes_written);
    593     succeeded = true;
    594   }
    595 
    596   if (should_continue) {
    597     WriteDataChunkIntoSnapshotFile();
    598     return;
    599   }
    600   if (succeeded) {
    601     current_snapshot_details_->request_info().success_callback.Run(
    602         current_snapshot_details_->file_info(),
    603         current_snapshot_details_->request_info().snapshot_file_path);
    604   } else {
    605     current_snapshot_details_->request_info().error_callback.Run(
    606         base::PLATFORM_FILE_ERROR_FAILED);
    607   }
    608   task_in_progress_ = false;
    609   current_snapshot_details_.reset();
    610   ProcessNextPendingRequest();
    611 }
    612