cloned_install_detector.cc revision cedac228d2dd51db4b79ea1e72c7f249408ee061
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#include "components/metrics/cloned_install_detector.h" 6 7#include "base/bind.h" 8#include "base/location.h" 9#include "base/metrics/histogram.h" 10#include "base/prefs/pref_registry_simple.h" 11#include "base/prefs/pref_service.h" 12#include "base/single_thread_task_runner.h" 13#include "base/task_runner_util.h" 14#include "components/metrics/cloned_install_detector.h" 15#include "components/metrics/machine_id_provider.h" 16#include "components/metrics/metrics_hashes.h" 17#include "components/metrics/metrics_pref_names.h" 18 19namespace metrics { 20 21namespace { 22 23uint32 HashRawId(const std::string& value) { 24 uint64 hash = metrics::HashMetricName(value); 25 26 // Only use 24 bits from the 64-bit hash. 27 return hash & ((1 << 24) - 1); 28} 29 30// State of the generated machine id in relation to the previously stored value. 31// Note: UMA histogram enum - don't re-order or remove entries 32enum MachineIdState { 33 ID_GENERATION_FAILED, 34 ID_NO_STORED_VALUE, 35 ID_CHANGED, 36 ID_UNCHANGED, 37 ID_ENUM_SIZE 38}; 39 40// Logs the state of generating a machine id and comparing it to a stored value. 41void LogMachineIdState(MachineIdState state) { 42 UMA_HISTOGRAM_ENUMERATION("UMA.MachineIdState", state, ID_ENUM_SIZE); 43} 44 45} // namespace 46 47ClonedInstallDetector::ClonedInstallDetector(MachineIdProvider* raw_id_provider) 48 : raw_id_provider_(raw_id_provider), weak_ptr_factory_(this) { 49} 50 51ClonedInstallDetector::~ClonedInstallDetector() { 52} 53 54void ClonedInstallDetector::CheckForClonedInstall( 55 PrefService* local_state, 56 scoped_refptr<base::SingleThreadTaskRunner> task_runner) { 57 base::PostTaskAndReplyWithResult( 58 task_runner.get(), 59 FROM_HERE, 60 base::Bind(&metrics::MachineIdProvider::GetMachineId, raw_id_provider_), 61 base::Bind(&metrics::ClonedInstallDetector::SaveMachineId, 62 weak_ptr_factory_.GetWeakPtr(), 63 local_state)); 64} 65 66void ClonedInstallDetector::SaveMachineId(PrefService* local_state, 67 std::string raw_id) { 68 if (raw_id.empty()) { 69 LogMachineIdState(ID_GENERATION_FAILED); 70 local_state->ClearPref(prefs::kMetricsMachineId); 71 return; 72 } 73 74 int hashed_id = HashRawId(raw_id); 75 76 MachineIdState id_state = ID_NO_STORED_VALUE; 77 if (local_state->HasPrefPath(prefs::kMetricsMachineId)) { 78 if (local_state->GetInteger(prefs::kMetricsMachineId) != hashed_id) { 79 id_state = ID_CHANGED; 80 // TODO(jwd): Use a callback to set the reset pref. That way 81 // ClonedInstallDetector doesn't need to know about this pref. 82 local_state->SetBoolean(prefs::kMetricsResetIds, true); 83 } else { 84 id_state = ID_UNCHANGED; 85 } 86 } 87 88 LogMachineIdState(id_state); 89 90 local_state->SetInteger(prefs::kMetricsMachineId, hashed_id); 91} 92 93// static 94void ClonedInstallDetector::RegisterPrefs(PrefRegistrySimple* registry) { 95 registry->RegisterIntegerPref(prefs::kMetricsMachineId, 0); 96} 97 98} // namespace metrics 99