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

chrome/browser/media_gallery/win/recursive_mtp_device_object_enumerator.h

+// Copyright (c) 2013 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_RECURSIVE_MTP_DEVICE_OBJECT_ENUMERATOR_H_
+#define CHROME_BROWSER_MEDIA_GALLERY_WIN_RECURSIVE_MTP_DEVICE_OBJECT_ENUMERATOR_H_
+
+#include <portabledeviceapi.h>
+
+#include <queue>
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/string16.h"
+#include "base/threading/thread_checker.h"
+#include "base/time.h"
+#include "base/win/scoped_comptr.h"
+#include "chrome/browser/media_gallery/win/mtp_device_object_entry.h"
+#include "webkit/fileapi/file_system_file_util.h"
+
+class FilePath;
+
+namespace chrome {
+
+// RecursiveMTPDeviceObjectEnumerator is used to recursively enumerate the
+// media transfer protocol (MTP) device storage objects from a given media file
+// object entries set. RecursiveMTPDeviceObjectEnumerator communicates with the
+// MTP device to get the subdirectory object entries.
+// RecursiveMTPDeviceObjectEnumerator uses MTPDeviceObjectEnumerator to iterate
+// the current directory objects. RecursiveMTPDeviceObjectEnumerator may only be
+// used on a single thread.
+class RecursiveMTPDeviceObjectEnumerator
+    : public fileapi::FileSystemFileUtil::AbstractFileEnumerator {
+ public:
+  // MTP |device| should already be initialized and ready for communication.
+  RecursiveMTPDeviceObjectEnumerator(IPortableDevice* device,
+                                     const MTPDeviceObjectEntries& entries);
+  virtual ~RecursiveMTPDeviceObjectEnumerator();
+
+  // AbstractFileEnumerator:
+  virtual FilePath Next() OVERRIDE;
+  virtual int64 Size() OVERRIDE;
+  virtual bool IsDirectory() OVERRIDE;
+  virtual base::Time LastModifiedTime() OVERRIDE;
+
+ private:
+  typedef string16 DirectoryObjectId;
+
+  void MaybeUpdateCurrentObjectList();
+
+  // The portable device.
+  base::win::ScopedComPtr<IPortableDevice> device_;
+
+  // TODO(kmadhusu): Remove |curr_object_entries_| and |object_entry_iter_|.
+  // Implement GetObjectId() and HasMoreEntries() in MTPDeviceObjectEnumerator
+  // and remove |curr_object_entries_| and |object_entry_iter_|.
+
+  // List of current directory object entries.
+  MTPDeviceObjectEntries curr_object_entries_;
+
+  // Iterator to access the individual file object entries.
+  MTPDeviceObjectEntries::const_iterator object_entry_iter_;
+
+  // Enumerator to access current directory object entries.
+  scoped_ptr<fileapi::FileSystemFileUtil::AbstractFileEnumerator>
+      current_enumerator_;
+
+  // Used to recursively enumerate the sub-directory objects.
+  std::queue<DirectoryObjectId> unparsed_directory_object_ids_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(RecursiveMTPDeviceObjectEnumerator);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_MEDIA_GALLERY_WIN_RECURSIVE_MTP_DEVICE_OBJECT_ENUMERATOR_H_