chrome/browser/media_galleries/win/mtp_device_object_enumerator.h

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