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      1 // Copyright (c) 2012 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 #ifndef CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_MTP_DEVICE_MAP_SERVICE_H_
      6 #define CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_MTP_DEVICE_MAP_SERVICE_H_
      7 
      8 #include <map>
      9 
     10 #include "base/files/file_path.h"
     11 #include "base/lazy_instance.h"
     12 #include "base/threading/thread_checker.h"
     13 
     14 class MTPDeviceAsyncDelegate;
     15 
     16 // This class provides media transfer protocol (MTP) device delegate to
     17 // complete media file system operations.
     18 // Lives on the IO thread in production.
     19 // TODO(gbillock): Make this class owned by the MediaFileSystemRegistry.
     20 class MTPDeviceMapService {
     21  public:
     22   static MTPDeviceMapService* GetInstance();
     23 
     24   // Gets the media device delegate associated with |filesystem_id|.
     25   // Return NULL if the |filesystem_id| is no longer valid (e.g. because the
     26   // corresponding device is detached, etc).
     27   // Called on the IO thread.
     28   MTPDeviceAsyncDelegate* GetMTPDeviceAsyncDelegate(
     29       const std::string& filesystem_id);
     30 
     31   // Register that an MTP filesystem is in use for the given |device_location|.
     32   void RegisterMTPFileSystem(
     33     const base::FilePath::StringType& device_location,
     34     const std::string& fsid);
     35 
     36   // Removes the MTP entry associated with the given
     37   // |device_location|. Signals the MTPDeviceMapService to destroy the
     38   // delegate if there are no more uses of it.
     39   void RevokeMTPFileSystem(const std::string& fsid);
     40 
     41  private:
     42   friend struct base::DefaultLazyInstanceTraits<MTPDeviceMapService>;
     43 
     44   // Adds the MTP device delegate to the map service. |device_location|
     45   // specifies the mount location of the MTP device.
     46   // Called on the IO thread.
     47   void AddAsyncDelegate(const base::FilePath::StringType& device_location,
     48                         MTPDeviceAsyncDelegate* delegate);
     49 
     50   // Removes the MTP device delegate from the map service. |device_location|
     51   // specifies the mount location of the MTP device.
     52   // Called on the IO thread.
     53   void RemoveAsyncDelegate(const base::FilePath::StringType& device_location);
     54 
     55   // Mapping of device_location and MTPDeviceAsyncDelegate* object. It is safe
     56   // to store and access the raw pointer. This class operates on the IO thread.
     57   typedef std::map<base::FilePath::StringType, MTPDeviceAsyncDelegate*>
     58       AsyncDelegateMap;
     59 
     60   // Map a filesystem id (fsid) to an MTP device location.
     61   typedef std::map<std::string, base::FilePath::StringType>
     62       MTPDeviceFileSystemMap;
     63 
     64   // Map a MTP or PTP device location to a count of current uses of that
     65   // location.
     66   typedef std::map<const base::FilePath::StringType, int>
     67       MTPDeviceUsageMap;
     68 
     69 
     70   // Get access to this class using GetInstance() method.
     71   MTPDeviceMapService();
     72   ~MTPDeviceMapService();
     73 
     74   // Map of attached mtp device async delegates.
     75   AsyncDelegateMap async_delegate_map_;
     76 
     77   MTPDeviceFileSystemMap mtp_device_map_;
     78 
     79   MTPDeviceUsageMap mtp_device_usage_map_;
     80 
     81   DISALLOW_COPY_AND_ASSIGN(MTPDeviceMapService);
     82 };
     83 
     84 #endif  // CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_MTP_DEVICE_MAP_SERVICE_H_
     85