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// 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.
#include "components/metrics/cloned_install_detector.h"
#include <stdint.h>
#include <string>
#include "base/bind.h"
#include "base/location.h"
#include "base/metrics/histogram_macros.h"
#include "base/metrics/metrics_hashes.h"
#include "base/single_thread_task_runner.h"
#include "base/task_runner_util.h"
#include "components/metrics/machine_id_provider.h"
#include "components/metrics/metrics_pref_names.h"
#include "components/prefs/pref_registry_simple.h"
#include "components/prefs/pref_service.h"
namespace metrics {
namespace {
uint32_t HashRawId(const std::string& value) {
uint64_t hash = base::HashMetricName(value);
// Only use 24 bits from the 64-bit hash.
return hash & ((1 << 24) - 1);
}
// State of the generated machine id in relation to the previously stored value.
// Note: UMA histogram enum - don't re-order or remove entries
enum MachineIdState {
ID_GENERATION_FAILED,
ID_NO_STORED_VALUE,
ID_CHANGED,
ID_UNCHANGED,
ID_ENUM_SIZE
};
// Logs the state of generating a machine id and comparing it to a stored value.
void LogMachineIdState(MachineIdState state) {
UMA_HISTOGRAM_ENUMERATION("UMA.MachineIdState", state, ID_ENUM_SIZE);
}
} // namespace
ClonedInstallDetector::ClonedInstallDetector(MachineIdProvider* raw_id_provider)
: raw_id_provider_(raw_id_provider), weak_ptr_factory_(this) {
}
ClonedInstallDetector::~ClonedInstallDetector() {
}
void ClonedInstallDetector::CheckForClonedInstall(
PrefService* local_state,
scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
base::PostTaskAndReplyWithResult(
task_runner.get(),
FROM_HERE,
base::Bind(&MachineIdProvider::GetMachineId, raw_id_provider_),
base::Bind(&ClonedInstallDetector::SaveMachineId,
weak_ptr_factory_.GetWeakPtr(),
local_state));
}
void ClonedInstallDetector::SaveMachineId(PrefService* local_state,
const std::string& raw_id) {
if (raw_id.empty()) {
LogMachineIdState(ID_GENERATION_FAILED);
local_state->ClearPref(prefs::kMetricsMachineId);
return;
}
int hashed_id = HashRawId(raw_id);
MachineIdState id_state = ID_NO_STORED_VALUE;
if (local_state->HasPrefPath(prefs::kMetricsMachineId)) {
if (local_state->GetInteger(prefs::kMetricsMachineId) != hashed_id) {
id_state = ID_CHANGED;
// TODO(jwd): Use a callback to set the reset pref. That way
// ClonedInstallDetector doesn't need to know about this pref.
local_state->SetBoolean(prefs::kMetricsResetIds, true);
} else {
id_state = ID_UNCHANGED;
}
}
LogMachineIdState(id_state);
local_state->SetInteger(prefs::kMetricsMachineId, hashed_id);
}
// static
void ClonedInstallDetector::RegisterPrefs(PrefRegistrySimple* registry) {
registry->RegisterIntegerPref(prefs::kMetricsMachineId, 0);
}
} // namespace metrics
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