[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.
+//
+// This class supports media transfer protocol (MTP) device file system
+// operations. This class communicates with the portable device and completes
+// the requested file system operation. MTPDeviceMapService owns this object.
+// This object is constructed and destructed on UI thread. All the device
+// operations are performed on the blocking thread. A portable device can have
+// multiple data partitions. A user can register each partition as a media
+// file system. This class is instantitated per MTP device storage.
+
+#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 "base/memory/ref_counted.h"
+#include "base/platform_file.h"
+#include "base/string16.h"
+#include "base/win/scoped_comptr.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.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 {
+
+// Helper class to communicate with MTP storage to complete isolated file system
+// operations. This class contains platform specific code to communicate with
+// the attached MTP storage. Instantiate this class per MTP storage.
+// This class is ref-counted, because MtpDeviceDelegate is ref-counted.
+class MTPDeviceDelegateImplWin : public fileapi::MtpDeviceDelegate,
+                                 public content::NotificationObserver {
+ public:
+  // Constructed on UI thread. Defer the device initializations until the first
+  // file operation request. Do all the initializations in LazyInit() function.
+  explicit MTPDeviceDelegateImplWin(const string16& pnp_device_id);
+
+  // MtpDeviceDelegate:
+  virtual base::PlatformFileError GetFileInfo(
+      const FilePath& file_path,
+      base::PlatformFileInfo* file_info) OVERRIDE;
+  virtual 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 base::SequencedTaskRunner* media_task_runner() OVERRIDE;
+  virtual void DeleteOnCorrectThread() const OVERRIDE;
+
+ private:
+  friend struct fileapi::MtpDeviceDelegateDeleter;
+  friend class base::DeleteHelper<MTPDeviceDelegateImplWin>;
+
+  // Private because this class is ref-counted.
+  virtual ~MTPDeviceDelegateImplWin();
+
+  // content::NotificationObserver:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  // Opens the device for communication. This function is called on the
+  // sequenced task runner. Returns true if the device is ready for
+  // communication, else false.
+  bool LazyInit();
+
+  // The Pnp Device Id, used to open the device for communication,
+  // e.g. "\\?\usb#vid_04a9&pid_3073#12#{6ac27878-a6fa-4155-ba85-f1d4f33}".
+  string16 pnp_device_id_;
+
+  // The media file system root path, which is obtained during the registration
+  // of MTP device storage as a file system,
+  // e.g. "\\MTP:StorageSerial:SID-{10001,E,9823}:237483".
+  const string16 registered_device_path_;
+
+  // The MTP device storage object identifier, used to enumerate the storage
+  // contents, e.g. "s10001".
+  string16 storage_object_id_;
+
+  // The task runner used to execute tasks that may take a long time and thus
+  // should not be performed on the UI thread.
+  scoped_refptr<base::SequencedTaskRunner> media_task_runner_;
+
+  // The portable device.
+  base::win::ScopedComPtr<IPortableDevice> device_;
+
+    // Used to listen for NOTIFICATION_APP_TERMINATING message.

[Lei Zhang, 2012/11/01 02:34:57]

indentation

[kmadhusu, 2012/11/01 17:59:00]

Done.

+  content::NotificationRegistrar registrar_;
+
+  // Used to notify the blocking tasks about the application termination
+  // message.
+  bool app_terminating_;

[kmadhusu, 2012/11/01 02:38:00]

Just realized that I should have used cancellation flag instead of bool here.
Because this variable is set on UI thread and checked on task runner thread.
Will fix it in the next patch. 

[kmadhusu, 2012/11/01 17:59:00]

Fixed.

+
+  DISALLOW_COPY_AND_ASSIGN(MTPDeviceDelegateImplWin);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_MEDIA_GALLERY_WIN_MTP_DEVICE_DELEGATE_IMPL_WIN_H_