chrome/browser/storage_monitor/transient_device_ids.h

   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 // 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 CHROME_BROWSER_STORAGE_MONITOR_TRANSIENT_DEVICE_IDS_H_
  11 #define CHROME_BROWSER_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 class TransientDeviceIds {
  20  public:
  21   TransientDeviceIds();
  22   ~TransientDeviceIds();
  23
  24   // Returns the transient ID for a given |device_id|.
  25   // |device_id| must be for a fixed or removable storage device.
  26   // If |device_id| has never been seen before, a new, unique transient id will
  27   // be assigned.
  28   std::string GetTransientIdForDeviceId(const std::string& device_id);
  29
  30   // Get the reverse mapping for a transient ID. Returns an empty string if the
  31   // |transient_id| cannot be found.
  32   std::string DeviceIdFromTransientId(const std::string& transient_id) const;
  33
  34  private:
  35   typedef std::map<std::string, std::string> IdMap;
  36
  37   IdMap device_id_map_;
  38   IdMap transient_id_map_;
  39
  40   base::ThreadChecker thread_checker_;
  41
  42   DISALLOW_COPY_AND_ASSIGN(TransientDeviceIds);
  43 };
  44
  45 #endif  // CHROME_BROWSER_STORAGE_MONITOR_TRANSIENT_DEVICE_IDS_H_