[Linux, Media Gallery] Fix MTPRecursiveDeviceObjectEnumerator to recursively enumerate all the medi…

chrome/browser/media_gallery/linux/mtp_recursive_device_object_enumerator.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.
 
 #ifndef CHROME_BROWSER_MEDIA_GALLERY_LINUX_MTP_RECURSIVE_DEVICE_OBJECT_ENUMERATOR_H_
 #define CHROME_BROWSER_MEDIA_GALLERY_LINUX_MTP_RECURSIVE_DEVICE_OBJECT_ENUMERATOR_H_
 
+#include <queue>
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/time.h"
 #include "device/media_transfer_protocol/mtp_file_entry.pb.h"
 #include "webkit/fileapi/file_system_file_util.h"
 
 namespace base {
 class SequencedTaskRunner;
 class WaitableEvent;
 }
 
 namespace chrome {
 
+class MTPDeviceObjectEnumerator;
+
 // Recursively enumerate each file entry from a given media file entry set.
 class MTPRecursiveDeviceObjectEnumerator
     : public fileapi::FileSystemFileUtil::AbstractFileEnumerator {
  public:
   MTPRecursiveDeviceObjectEnumerator(const std::string& handle,
                                      base::SequencedTaskRunner* task_runner,
                                      const std::vector<MtpFileEntry>& entries,
                                      base::WaitableEvent* task_completed_event,
                                      base::WaitableEvent* shutdown_event);
 
   virtual ~MTPRecursiveDeviceObjectEnumerator();
 
   // AbstractFileEnumerator:
   virtual FilePath Next() OVERRIDE;
   virtual int64 Size() OVERRIDE;
   virtual bool IsDirectory() OVERRIDE;
   virtual base::Time LastModifiedTime() OVERRIDE;
 
  private:
+  typedef uint32_t DirectoryEntryId;
+
+  // Returns an enumerator to traverse the subdirectory objects. If there
+  // is no subdirectory, returns NULL. The caller owns the returned
+  // MTPDeviceObjectEnumerator.
+  scoped_ptr<MTPDeviceObjectEnumerator> GetSubdirectoryEnumerator();
+
   // Stores the device handle that was used to open the device.
   const std::string device_handle_;
 
   // Stores a reference to |media_task_runner_| to construct and destruct
   // ReadMTPDirectoryWorker object on the correct thread.
   scoped_refptr<base::SequencedTaskRunner> media_task_runner_;
 
-  // List of top-level directory file entries.
-  const std::vector<MtpFileEntry> file_entries_;
+  // Enumerator to access current directory Id/path entries.
+  scoped_ptr<MTPDeviceObjectEnumerator> current_enumerator_;
 
-  // Iterator to access the individual file entries.
-  std::vector<MtpFileEntry>::const_iterator file_entry_iter_;
+  scoped_ptr<fileapi::FileSystemFileUtil::AbstractFileEnumerator>
+      empty_enumerator_;
 
-  // Enumerator to access current directory Id/path entries.
-  scoped_ptr<fileapi::FileSystemFileUtil::AbstractFileEnumerator>
-      current_enumerator_;
+  // Queue of untraversed directories.
+  std::queue<DirectoryEntryId> untraversed_directory_entry_ids_;
 
   // |media_task_runner_| can wait on this event until the requested operation
   // is complete.
   base::WaitableEvent* on_task_completed_event_;
 
   // Stores a reference to waitable event associated with the shut down message.
   base::WaitableEvent* on_shutdown_event_;
 
   DISALLOW_COPY_AND_ASSIGN(MTPRecursiveDeviceObjectEnumerator);
 };
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_MEDIA_GALLERY_LINUX_MTP_RECURSIVE_DEVICE_OBJECT_ENUMERATOR_H_