chrome/browser/metrics/cloned_install_detector.h

// Copyright 2014 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_METRICS_CLONED_INSTALL_DETECTOR_H_
#define CHROME_BROWSER_METRICS_CLONED_INSTALL_DETECTOR_H_

#include "base/gtest_prod_util.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"

class PrefRegistrySimple;
class PrefService;

namespace metrics {

class MachineIdProvider;

// A class for detecting if an install is cloned. It does this by detecting
// when the hardware running Chrome changes.
class ClonedInstallDetector {
 public:
  explicit ClonedInstallDetector(MachineIdProvider* raw_id_provider);
  virtual ~ClonedInstallDetector();

  // Posts a task to generate a machine ID and store it to a local state pref.
  // If the newly generated ID is different than the previously stored one, then
  // the install is considered cloned. The ID is a 24-bit value based off of
  // machine characteristics. This value should never be sent over the network.
  // TODO(jwd): Implement change detection.
  void CheckForClonedInstall(PrefService* local_state);

  static void RegisterPrefs(PrefRegistrySimple* registry);

 private:
  FRIEND_TEST_ALL_PREFIXES(ClonedInstallDetectorTest, SaveId);

  // Converts raw_id into a 24-bit hash and stores the hash in |local_state|.
  // |raw_id| is not a const ref because it's passed from a cross-thread post
  // task.
  void SaveMachineId(PrefService* local_state, std::string raw_id);

  scoped_refptr<MachineIdProvider> raw_id_provider_;
  base::WeakPtrFactory<ClonedInstallDetector> weak_ptr_factory_;

  DISALLOW_COPY_AND_ASSIGN(ClonedInstallDetector);
};

}  // namespace metrics

#endif  // CHROME_BROWSER_METRICS_CLONED_INSTALL_DETECTOR_H_