// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/ash/hats/hats_finch_helper.h"
#include "base/metrics/field_trial_params.h"
#include "base/rand_util.h"
#include "base/strings/string_util.h"
#include "chrome/browser/ash/hats/hats_config.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/chrome_features.h"
#include "chrome/common/pref_names.h"
#include "components/prefs/pref_service.h"
namespace ash {
// These values should match the param key values in the finch config file.
// static
const char HatsFinchHelper::kEnabledForGooglersParam[] = "enabled_for_googlers";
// static
const char HatsFinchHelper::kCustomClientDataParam[] = "custom_client_data";
// static
const char HatsFinchHelper::kProbabilityParam[] = "prob";
// static
const char HatsFinchHelper::kResetAllParam[] = "reset_all";
// static
const char HatsFinchHelper::kResetSurveyCycleParam[] = "reset_survey_cycle";
// static
const char HatsFinchHelper::kSurveyCycleLengthParam[] = "survey_cycle_length";
// static
const char HatsFinchHelper::kSurveyStartDateMsParam[] = "survey_start_date_ms";
// static
const char HatsFinchHelper::kTriggerIdParam[] = "trigger_id";
const char HatsFinchHelper::kHistogramNameParam[] = "histogram_name";
std::string HatsFinchHelper::GetTriggerID(const HatsConfig& hats_config) {
DCHECK(base::FeatureList::IsEnabled(hats_config.feature));
return base::GetFieldTrialParamValueByFeature(hats_config.feature,
kTriggerIdParam);
}
// To enable UMA collection for a specific survey, the Finch configuration
// file for this survey should be updated to include a `histogram_name`
// parameter along side the `trigger_id` parameter. Without this
// `histogram_name` parameter specified, no survey-specific UMA data will be
// collected.
std::string HatsFinchHelper::GetHistogramName(const HatsConfig& hats_config) {
DCHECK(base::FeatureList::IsEnabled(hats_config.feature));
// Fetch the histogram name from the feature parameters, if it is assigned.
// An empty string will be returned if the parameter is not set in Finch.
// This value should be a valid histogram that has been registered in the
// histograms.xml file, otherwise it will not be ingested by UMA.
std::string histogram_name = base::GetFieldTrialParamValueByFeature(
hats_config.feature, kHistogramNameParam);
// Valid histogram names for HaTS/UMA integration must start with the
// prefix "ChromeOS.HaTS.". This corresponds to the histogram definition
// in the histograms.xml file.
if (!base::StartsWith(histogram_name, "ChromeOS.HaTS.")) {
LOG(ERROR) << "Invalid HaTS histogram name: " << histogram_name;
return std::string();
}
return histogram_name;
}
std::string HatsFinchHelper::GetCustomClientDataAsString(
const HatsConfig& hats_config) {
DCHECK(base::FeatureList::IsEnabled(hats_config.feature));
return base::GetFieldTrialParamValueByFeature(hats_config.feature,
kCustomClientDataParam);
}
bool HatsFinchHelper::IsEnabledForGooglers(const HatsConfig& hats_config) {
DCHECK(base::FeatureList::IsEnabled(hats_config.feature));
return base::GetFieldTrialParamByFeatureAsBool(
hats_config.feature, kEnabledForGooglersParam, false);
}
HatsFinchHelper::HatsFinchHelper(Profile* profile,
const HatsConfig& hats_config)
: profile_(profile), hats_config_(hats_config) {
LoadFinchParamValues(hats_config);
// Reset prefs related to survey cycle if the finch seed has the reset param
// set. Do no futher op until a new finch seed with the reset flags unset is
// received.
// Warning: |reset_hats_| applies to all surveys.
if (reset_survey_cycle_ || reset_hats_) {
profile_->GetPrefs()->ClearPref(hats_config.cycle_end_timestamp_pref_name);
profile_->GetPrefs()->ClearPref(hats_config.is_selected_pref_name);
if (reset_hats_)
profile_->GetPrefs()->ClearPref(prefs::kHatsLastInteractionTimestamp);
return;
}
CheckForDeviceSelection();
}
HatsFinchHelper::~HatsFinchHelper() = default;
void HatsFinchHelper::LoadFinchParamValues(const HatsConfig& hats_config) {
if (!base::FeatureList::IsEnabled(hats_config.feature))
return;
probability_of_pick_ = base::GetFieldTrialParamByFeatureAsDouble(
hats_config.feature, kProbabilityParam, -1.0);
if (probability_of_pick_ < 0.0 || probability_of_pick_ > 1.0) {
LOG(ERROR) << "Invalid value for probability: " << probability_of_pick_;
probability_of_pick_ = 0;
}
survey_cycle_length_ = base::GetFieldTrialParamByFeatureAsInt(
hats_config.feature, kSurveyCycleLengthParam, 0);
if (survey_cycle_length_ <= 0) {
LOG(ERROR) << "Invalid value for survey cycle length: "
<< survey_cycle_length_;
survey_cycle_length_ = INT_MAX;
}
double first_survey_start_date_ms = base::GetFieldTrialParamByFeatureAsDouble(
hats_config.feature, kSurveyStartDateMsParam, -1.0);
if (first_survey_start_date_ms < 0) {
LOG(ERROR) << "Invalid timestamp for survey start date: "
<< first_survey_start_date_ms;
// Set a random date in the distant future so that the survey never starts
// until a new finch seed is received with the correct start date.
first_survey_start_date_ms =
2 * base::Time::Now().InMillisecondsFSinceUnixEpoch();
}
first_survey_start_date_ =
base::Time().FromMillisecondsSinceUnixEpoch(first_survey_start_date_ms);
trigger_id_ = GetTriggerID(hats_config);
reset_survey_cycle_ = base::GetFieldTrialParamByFeatureAsBool(
hats_config.feature, kResetSurveyCycleParam, false);
reset_hats_ = base::GetFieldTrialParamByFeatureAsBool(hats_config.feature,
kResetAllParam, false);
// Set every property to no op values if this is a reset finch seed.
if (reset_survey_cycle_ || reset_hats_) {
probability_of_pick_ = 0;
survey_cycle_length_ = INT_MAX;
first_survey_start_date_ = base::Time().FromMillisecondsSinceUnixEpoch(
2 * base::Time::Now().InMillisecondsFSinceUnixEpoch());
}
}
bool HatsFinchHelper::HasPreviousCycleEnded() {
int64_t serialized_timestamp = profile_->GetPrefs()->GetInt64(
hats_config_->cycle_end_timestamp_pref_name);
base::Time recent_survey_cycle_end_time =
base::Time::FromInternalValue(serialized_timestamp);
return recent_survey_cycle_end_time < base::Time::Now();
}
base::Time HatsFinchHelper::ComputeNextEndDate() {
base::Time start_date = first_survey_start_date_;
base::TimeDelta delta = base::Days(survey_cycle_length_);
do {
start_date += delta;
} while (start_date < base::Time::Now());
return start_date;
}
void HatsFinchHelper::CheckForDeviceSelection() {
device_is_selected_for_cycle_ = false;
// The dice is rolled only once per survey cycle. If it has already been done
// for the current cycle, then return the stored value of the result.
if (!HasPreviousCycleEnded()) {
device_is_selected_for_cycle_ =
profile_->GetPrefs()->GetBoolean(hats_config_->is_selected_pref_name);
return;
}
// If the start date for the survey is in the future, do nothing.
if (first_survey_start_date_ > base::Time::Now())
return;
// Start a new survey cycle and compute its end date.
base::Time survey_cycle_end_date = ComputeNextEndDate();
PrefService* pref_service = profile_->GetPrefs();
pref_service->SetInt64(hats_config_->cycle_end_timestamp_pref_name,
survey_cycle_end_date.ToInternalValue());
double rand_double = base::RandDouble();
bool is_selected = false;
if (rand_double < probability_of_pick_)
is_selected = true;
// Check if the trigger id is a valid string. Trigger IDs are a hash strings
// of around 26 characters.
is_selected = is_selected && (trigger_id_.length() > 15);
pref_service->SetBoolean(hats_config_->is_selected_pref_name, is_selected);
device_is_selected_for_cycle_ = is_selected;
}
} // namespace ash
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