[Media Gallery] Added code to support mtp device media file system on Windows.

chrome/browser/media_gallery/win/mtp_device_delegate_impl_win.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// MTPDeviceDelegateImplWin implementation.
+
+#include "chrome/browser/media_gallery/win/mtp_device_delegate_impl_win.h"
+
+#include <portabledevice.h>
+#include <vector>
+
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/memory/ref_counted.h"
+#include "base/sequenced_task_runner.h"
+#include "base/sequenced_task_runner_helpers.h"
+#include "base/string_split.h"
+#include "base/string_util.h"
+#include "base/threading/thread_restrictions.h"
+#include "base/utf_string_conversions.h"
+#include "chrome/browser/media_gallery/win/mtp_device_object_entry.h"
+#include "chrome/browser/media_gallery/win/mtp_device_object_enumerator.h"
+#include "chrome/browser/media_gallery/win/mtp_device_operations_util.h"
+#include "chrome/browser/media_gallery/win/recursive_mtp_device_object_enumerator.h"
+#include "chrome/browser/system_monitor/removable_device_notifications_window_win.h"
+#include "chrome/browser/system_monitor/removable_storage_notifications.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace chrome {
+
+namespace {
+
+// Gets the details of the MTP partition storage specified by the
+// |storage_path| on the UI thread. If the storage details are valid, creates a
+// MTP device delegate on the media task runner.
+void GetStorageInfoAndMaybeCreateDelegate(
+    const string16& storage_path,
+    const scoped_refptr<base::SequencedTaskRunner>& media_task_runner,
+    const CreateMTPDeviceDelegateCallback& callback) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  DCHECK(!storage_path.empty());
+  DCHECK(media_task_runner.get());
+  string16 storage_device_id;
+  RemoveChars(storage_path, L"\\\\", &storage_device_id);
+  DCHECK(!storage_device_id.empty());
+  RemovableStorageNotifications* notifications =
+      RemovableStorageNotifications::GetInstance();
+  DCHECK(notifications);
+  string16 pnp_device_id;
+  string16 storage_object_id;
+  if ((!notifications->GetMTPStorageInfoFromDeviceId(
+          UTF16ToUTF8(storage_device_id), &pnp_device_id,
+          &storage_object_id)) ||
+       pnp_device_id.empty() ||
+       storage_object_id.empty())
+    return;
+  media_task_runner->PostTask(FROM_HERE,
+                              base::Bind(&OnGotStorageInfoCreateDelegate,
+                                         storage_path,
+                                         media_task_runner,
+                                         callback,
+                                         pnp_device_id,
+                                         storage_object_id));
+}
+
+}  // namespace
+
+// Used by GetStorageInfoAndMaybeCreateDelegate() to create the MTP device
+// delegate on the media task runner.
+void OnGotStorageInfoCreateDelegate(
+    const string16& device_location,
+    base::SequencedTaskRunner* media_task_runner,
+    const CreateMTPDeviceDelegateCallback& callback,
+    const string16& pnp_device_id,
+    const string16& storage_object_id) {
+  DCHECK(media_task_runner);
+  DCHECK(media_task_runner->RunsTasksOnCurrentThread());
+  callback.Run(new MTPDeviceDelegateImplWin(device_location,
+                                            pnp_device_id,
+                                            storage_object_id,
+                                            media_task_runner));
+}
+
+void CreateMTPDeviceDelegate(const string16& device_location,
+                             base::SequencedTaskRunner* media_task_runner,
+                             const CreateMTPDeviceDelegateCallback& callback) {
+  DCHECK(media_task_runner);
+  DCHECK(media_task_runner->RunsTasksOnCurrentThread());
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&GetStorageInfoAndMaybeCreateDelegate,
+                 device_location,
+                 make_scoped_refptr(media_task_runner),
+                 callback));
+}
+
+// MTPDeviceDelegateImplWin ---------------------------------------------------
+
+MTPDeviceDelegateImplWin::MTPDeviceDelegateImplWin(
+    const string16& fs_root_path,
+    const string16& pnp_device_id,
+    const string16& storage_object_id,
+    base::SequencedTaskRunner* media_task_runner)
+    : registered_device_path_(fs_root_path),
+      pnp_device_id_(pnp_device_id),
+      storage_object_id_(storage_object_id),
+      media_task_runner_(media_task_runner),
+      cancel_pending_tasks_(false) {
+  DCHECK(!pnp_device_id_.empty());
+  DCHECK(!storage_object_id_.empty());
+  DCHECK(media_task_runner_.get());
+}
+
+MTPDeviceDelegateImplWin::~MTPDeviceDelegateImplWin() {
+  DCHECK(media_task_runner_->RunsTasksOnCurrentThread());
+}
+
+base::PlatformFileError MTPDeviceDelegateImplWin::GetFileInfo(
+    const FilePath& file_path,
+    base::PlatformFileInfo* file_info) {
+  if (!LazyInit())
+    return base::PLATFORM_FILE_ERROR_FAILED;
+  string16 object_id = GetFileObjectIdFromPath(file_path.value());
+  if (object_id.empty())
+    return base::PLATFORM_FILE_ERROR_FAILED;
+  return media_transfer_protocol::GetFileEntryInfo(device_.get(), object_id,
+                                                   file_info);
+}
+
+scoped_ptr<fileapi::FileSystemFileUtil::AbstractFileEnumerator>
+    MTPDeviceDelegateImplWin::CreateFileEnumerator(const FilePath& root,
+                                                   bool recursive) {
+  scoped_ptr<fileapi::FileSystemFileUtil::AbstractFileEnumerator>
+      file_enumerator(new fileapi::FileSystemFileUtil::EmptyFileEnumerator());
+  if (root.value().empty() || !LazyInit())

[Lei Zhang, 2013/01/14 23:25:30]

nit: root.empty()

[kmadhusu, 2013/01/15 19:08:17]

Done.

+    return file_enumerator.Pass();
+
+  string16 object_id = GetFileObjectIdFromPath(root.value());
+  if (object_id.empty())
+    return file_enumerator.Pass();
+
+  MTPDeviceObjectEntries entries;
+  if (!media_transfer_protocol::GetDirectoryEntries(device_.get(), object_id,
+                                                    &entries) ||
+      entries.empty())
+    return file_enumerator.Pass();
+
+  if (recursive) {
+    file_enumerator.reset(
+        new RecursiveMTPDeviceObjectEnumerator(device_.get(), entries));
+  } else {
+    file_enumerator.reset(new MTPDeviceObjectEnumerator(entries));
+  }
+  return file_enumerator.Pass();
+}
+
+base::PlatformFileError MTPDeviceDelegateImplWin::CreateSnapshotFile(
+    const FilePath& device_file_path,
+    const FilePath& local_path,
+    base::PlatformFileInfo* file_info) {
+  if (!LazyInit())
+    return base::PLATFORM_FILE_ERROR_FAILED;
+  string16 file_object_id = GetFileObjectIdFromPath(device_file_path.value());
+  if (file_object_id.empty())
+    return base::PLATFORM_FILE_ERROR_FAILED;
+  if (!media_transfer_protocol::WriteFileObjectData(device_.get(),
+                                                    file_object_id,
+                                                    local_path))
+    return base::PLATFORM_FILE_ERROR_FAILED;
+  base::PlatformFileError error = GetFileInfo(device_file_path, file_info);

[Lei Zhang, 2013/01/14 23:25:30]

You should do this before writing the file to disk. Otherwise you can fail, but
wrote a file to disk.

[kmadhusu, 2013/01/15 19:08:17]

Done.

+
+  // LocalFileStreamReader is used to read the contents of the snapshot file.
+  // Snapshot file modification time does not match the last modified time
+  // of the original media file. Therefore, set the last modified time to null
+  // in order to avoid the verification in LocalFileStreamReader.
+  //
+  // Users will use HTML5 FileSystem Entry getMetadata() interface to get the
+  // actual last modified time of the media file.
+  file_info->last_modified = base::Time();
+  return error;
+}
+
+void MTPDeviceDelegateImplWin::CancelPendingTasksAndDeleteDelegate() {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  {
+    base::AutoLock locked(cancel_tasks_lock_);
+    cancel_pending_tasks_ = true;
+  }
+  media_task_runner_->DeleteSoon(FROM_HERE, this);
+}
+
+bool MTPDeviceDelegateImplWin::LazyInit() {
+  DCHECK(media_task_runner_->RunsTasksOnCurrentThread());
+  // Both OpenDevice() (which we call below) and any operations our callers do
+  // may take some time. Abort them immediately if we're in the process of
+  // shutting down.
+  {
+    base::AutoLock locked(cancel_tasks_lock_);
+    if (cancel_pending_tasks_)
+      return false;
+  }
+  if (device_.get())
+    return true;  // Already successfully initialized.
+  return media_transfer_protocol::OpenDevice(pnp_device_id_, &device_);
+}
+
+string16 MTPDeviceDelegateImplWin::GetFileObjectIdFromPath(
+    const string16& file_path) {
+  DCHECK(media_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK(!file_path.empty());
+  if (registered_device_path_ == file_path)
+    return storage_object_id_;
+
+  string16 actual_file_path(file_path);
+  ReplaceFirstSubstringAfterOffset(&actual_file_path, 0,
+                                   registered_device_path_, string16());
+  DCHECK(!actual_file_path.empty());
+  typedef std::vector<string16> PathComponents;
+  PathComponents path_components;
+  base::SplitString(actual_file_path, L'\\', &path_components);
+  DCHECK(!path_components.empty());
+  string16 parent_id(storage_object_id_);
+  string16 file_object_id;
+  for (PathComponents::const_iterator path_iter = path_components.begin() + 1;
+       path_iter != path_components.end(); ++path_iter) {
+    file_object_id = media_transfer_protocol::GetObjectIdFromName(device_,
+                                                                  parent_id,
+                                                                  *path_iter);
+    if (file_object_id.empty())
+      break;
+    parent_id = file_object_id;
+  }
+  return file_object_id;
+}
+
+}  // namespace chrome