mtp_device_object_enumerator.h revision d0247b1b59f9c528cb6df88b4f2b9afaf80d181e 
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// This class enumerates the media transfer protocol (MTP) device objects from
6// a given object entry list.
7
8#ifndef CHROME_BROWSER_MEDIA_GALLERIES_WIN_MTP_DEVICE_OBJECT_ENUMERATOR_H_
9#define CHROME_BROWSER_MEDIA_GALLERIES_WIN_MTP_DEVICE_OBJECT_ENUMERATOR_H_
10
11#include "base/files/file_path.h"
12#include "base/threading/thread_checker.h"
13#include "base/time/time.h"
14#include "chrome/browser/media_galleries/win/mtp_device_object_entry.h"
15#include "webkit/browser/fileapi/file_system_file_util.h"
16
17// MTPDeviceObjectEnumerator is used to enumerate the media transfer protocol
18// (MTP) device objects from a given object entry list.
19// MTPDeviceObjectEnumerator supports MTP device file operations.
20// MTPDeviceObjectEnumerator may only be used on a single thread.
21class MTPDeviceObjectEnumerator
22    : public fileapi::FileSystemFileUtil::AbstractFileEnumerator {
23 public:
24  explicit MTPDeviceObjectEnumerator(const MTPDeviceObjectEntries& entries);
25  virtual ~MTPDeviceObjectEnumerator();
26
27  // AbstractFileEnumerator:
28  virtual base::FilePath Next() OVERRIDE;
29  virtual int64 Size() OVERRIDE;
30  virtual bool IsDirectory() OVERRIDE;
31  virtual base::Time LastModifiedTime() OVERRIDE;
32
33  // If the current file object entry is valid, returns an non-empty object id.
34  // Returns an empty string otherwise.
35  string16 GetObjectId() const;
36
37 private:
38  // Returns true if the enumerator has more entries to traverse, false
39  // otherwise.
40  bool HasMoreEntries() const;
41
42  // Returns true if Next() has been called at least once, and the enumerator
43  // has more entries to traverse.
44  bool IsIndexReadyAndInRange() const;
45
46  // List of directory file object entries.
47  MTPDeviceObjectEntries object_entries_;
48
49  // Index into |object_entries_|.
50  // Should only be used when |is_index_ready_| is true.
51  size_t index_;
52
53  // Initially false. Set to true after Next() has been called.
54  bool is_index_ready_;
55
56  base::ThreadChecker thread_checker_;
57
58  DISALLOW_COPY_AND_ASSIGN(MTPDeviceObjectEnumerator);
59};
60
61#endif  // CHROME_BROWSER_MEDIA_GALLERIES_WIN_MTP_DEVICE_OBJECT_ENUMERATOR_H_
62