components/storage_monitor/transient_device_ids.h

   1 // Copyright 2014 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 // TransientDeviceIds keep track of transient IDs for removable devices, so
   6 // persistent device IDs are not exposed to renderers. Once a removable device
   7 // gets mapped to a transient ID, the mapping remains valid for the duration of
   8 // TransientDeviceIds' lifetime.
   9
  10 #ifndef COMPONENTS_STORAGE_MONITOR_TRANSIENT_DEVICE_IDS_H_
  11 #define COMPONENTS_STORAGE_MONITOR_TRANSIENT_DEVICE_IDS_H_
  12
  13 #include <map>
  14 #include <string>
  15
  16 #include "base/basictypes.h"
  17 #include "base/threading/thread_checker.h"
  18
  19 namespace storage_monitor {
  20
  21 class TransientDeviceIds {
  22  public:
  23   TransientDeviceIds();
  24   ~TransientDeviceIds();
  25
  26   // Returns the transient ID for a given |device_id|.
  27   // |device_id| must be for a fixed or removable storage device.
  28   // If |device_id| has never been seen before, a new, unique transient id will
  29   // be assigned.
  30   std::string GetTransientIdForDeviceId(const std::string& device_id);
  31
  32   // Get the reverse mapping for a transient ID. Returns an empty string if the
  33   // |transient_id| cannot be found.
  34   std::string DeviceIdFromTransientId(const std::string& transient_id) const;
  35
  36  private:
  37   typedef std::map<std::string, std::string> IdMap;
  38
  39   IdMap device_id_map_;
  40   IdMap transient_id_map_;
  41
  42   base::ThreadChecker thread_checker_;
  43
  44   DISALLOW_COPY_AND_ASSIGN(TransientDeviceIds);
  45 };
  46
  47 }  // namespace storage_monitor
  48
  49 #endif  // COMPONENTS_STORAGE_MONITOR_TRANSIENT_DEVICE_IDS_H_