mtp_device_object_enumerator.h revision eb525c5499e34cc9c4b825d6d9e75bb07cc06ace 
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
17namespace chrome {
18
19// MTPDeviceObjectEnumerator is used to enumerate the media transfer protocol
20// (MTP) device objects from a given object entry list.
21// MTPDeviceObjectEnumerator supports MTP device file operations.
22// MTPDeviceObjectEnumerator may only be used on a single thread.
23class MTPDeviceObjectEnumerator
24    : public fileapi::FileSystemFileUtil::AbstractFileEnumerator {
25 public:
26  explicit MTPDeviceObjectEnumerator(const MTPDeviceObjectEntries& entries);
27  virtual ~MTPDeviceObjectEnumerator();
28
29  // AbstractFileEnumerator:
30  virtual base::FilePath Next() OVERRIDE;
31  virtual int64 Size() OVERRIDE;
32  virtual bool IsDirectory() OVERRIDE;
33  virtual base::Time LastModifiedTime() OVERRIDE;
34
35  // If the current file object entry is valid, returns an non-empty object id.
36  // Returns an empty string otherwise.
37  string16 GetObjectId() const;
38
39 private:
40  // Returns true if the enumerator has more entries to traverse, false
41  // otherwise.
42  bool HasMoreEntries() const;
43
44  // Returns true if Next() has been called at least once, and the enumerator
45  // has more entries to traverse.
46  bool IsIndexReadyAndInRange() const;
47
48  // List of directory file object entries.
49  MTPDeviceObjectEntries object_entries_;
50
51  // Index into |object_entries_|.
52  // Should only be used when |is_index_ready_| is true.
53  size_t index_;
54
55  // Initially false. Set to true after Next() has been called.
56  bool is_index_ready_;
57
58  base::ThreadChecker thread_checker_;
59
60  DISALLOW_COPY_AND_ASSIGN(MTPDeviceObjectEnumerator);
61};
62
63}  // namespace chrome
64
65#endif  // CHROME_BROWSER_MEDIA_GALLERIES_WIN_MTP_DEVICE_OBJECT_ENUMERATOR_H_
66