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

chrome/browser/media_gallery/win/mtp_device_delegate_impl_win.h

+// 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.
+
+#ifndef CHROME_BROWSER_MEDIA_GALLERY_WIN_MTP_DEVICE_DELEGATE_IMPL_WIN_H_
+#define CHROME_BROWSER_MEDIA_GALLERY_WIN_MTP_DEVICE_DELEGATE_IMPL_WIN_H_
+
+#include <portabledeviceapi.h>
+#include <string>
+
+#include "base/platform_file.h"
+#include "base/sequenced_task_runner_helpers.h"
+#include "base/string16.h"
+#include "base/synchronization/lock.h"
+#include "base/win/scoped_comptr.h"
+#include "chrome/browser/media_gallery/mtp_device_delegate_impl.h"
+#include "webkit/fileapi/file_system_file_util.h"
+#include "webkit/fileapi/media/mtp_device_delegate.h"
+
+class FilePath;
+
+namespace base {
+class SequencedTaskRunner;
+}
+
+namespace chrome {
+
+// MTPDeviceDelegateImplWin is used to communicate with the media transfer
+// protocol (MTP) device to complete isolated file system operations. MTP
+// device can have multiple data storage partitions. MTPDeviceDelegateImplWin
+// is instantiated per MTP device storage partition using
+// CreateMTPDeviceDelegate(). MTPDeviceDelegateImplWin lives on a sequenced
+// task runner thread, except for CancelPendingTasksAndDeleteDelegate() which
+// happens on the UI thread.
+class MTPDeviceDelegateImplWin : public fileapi::MTPDeviceDelegate {
+ private:
+  friend void OnGotStorageInfoCreateDelegate(
+      const string16& device_location,
+      base::SequencedTaskRunner* media_task_runner,
+      const CreateMTPDeviceDelegateCallback& callback,
+      const string16& pnp_device_id,
+      const string16& storage_object_id);
+
+  friend class base::DeleteHelper<MTPDeviceDelegateImplWin>;
+
+  // Defer the device initializations until the first file operation request.

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

nit: Defers

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

Done.

+  // Do all the initializations in LazyInit() function.
+  MTPDeviceDelegateImplWin(const string16& fs_root_path,
+                           const string16& pnp_device_id,
+                           const string16& storage_object_id,
+                           base::SequencedTaskRunner* media_task_runner);
+
+  // Destructed via CancelPendingTasksAndDeleteDelegate().
+  virtual ~MTPDeviceDelegateImplWin();
+
+  // MTPDeviceDelegate:
+  virtual base::PlatformFileError GetFileInfo(
+      const FilePath& file_path,
+      base::PlatformFileInfo* file_info) OVERRIDE;
+  virtual scoped_ptr<fileapi::FileSystemFileUtil::AbstractFileEnumerator>
+      CreateFileEnumerator(const FilePath& root,
+                           bool recursive) OVERRIDE;
+  virtual base::PlatformFileError CreateSnapshotFile(
+      const FilePath& device_file_path,
+      const FilePath& local_path,
+      base::PlatformFileInfo* file_info) OVERRIDE;
+  virtual void CancelPendingTasksAndDeleteDelegate() OVERRIDE;
+
+  // Returns whether the device is ready for communication.
+  bool LazyInit();
+
+  // Returns the object id of the file object specified by the |file_path|,
+  // e.g. if the |file_path| is "\\MTP:StorageSerial:SID-{1001,,192}:125\DCIM"
+  // and |registered_device_path_| is "\\MTP:StorageSerial:SID-{1001,,192}:125",
+  // this function returns the identifier of the "DCIM" folder object.
+  //
+  // Returns an empty string if the device is detached while the request is in
+  // progress.
+  string16 GetFileObjectIdFromPath(const string16& file_path);
+
+  // The Pnp Device Id, used to open the device for communication,

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

nit: plug & play abbreviates to PnP.

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

Done.

+  // e.g. "\\?\usb#vid_04a9&pid_3073#12#{6ac27878-a6fa-4155-ba85-f1d4f33}".
+  const string16 pnp_device_id_;
+
+  // The media file system root path, which is obtained during the registration
+  // of MTP device storage partition as a file system,
+  // e.g. "\\MTP:StorageSerial:SID-{10001,E,9823}:237483".
+  const string16 registered_device_path_;
+
+  // The MTP device storage partition object identifier, used to enumerate the
+  // storage contents, e.g. "s10001".
+  const string16 storage_object_id_;
+
+  // The task runner where most of the class lives and runs (save for
+  // CancelPendingTasksAndDeleteDelegate).
+  scoped_refptr<base::SequencedTaskRunner> media_task_runner_;
+
+  // The portable device.
+  base::win::ScopedComPtr<IPortableDevice> device_;
+
+  // The lock to protect |cancel_pending_tasks_|. |cancel_pending_tasks_| is
+  // set on the UI thread when the
+  // (1) Browser application is in shutdown mode (or)
+  // (2) Last extension using this MTP device is destroyed (or)
+  // (3) Attached MTP device is removed (or)
+  // (4) User revoked the MTP device gallery permission.
+  base::Lock cancel_tasks_lock_;
+  bool cancel_pending_tasks_;
+
+  DISALLOW_COPY_AND_ASSIGN(MTPDeviceDelegateImplWin);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_MEDIA_GALLERY_WIN_MTP_DEVICE_DELEGATE_IMPL_WIN_H_