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// Copyright 2023 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/readaloud/android/synthetic_trial.h"
#include <string>
#include <string_view>
#include <vector>
#include "base/feature_list.h"
#include "base/metrics/field_trial.h"
#include "base/strings/strcat.h"
#include "base/strings/string_split.h"
#include "base/values.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
#include "chrome/common/pref_names.h"
#include "components/prefs/pref_service.h"
#include "components/prefs/scoped_user_pref_update.h"
namespace readaloud {
namespace {
inline constexpr char kSeparator[] = "|||";
bool GetFeatureNameFromKey(const std::string& key, std::string_view* out) {
auto split_key = base::SplitStringPieceUsingSubstr(
key, kSeparator, base::WhitespaceHandling::KEEP_WHITESPACE,
base::SplitResult::SPLIT_WANT_NONEMPTY);
if (split_key.size() != 2) {
return false;
}
*out = split_key[0];
return true;
}
} // namespace
// static
void SyntheticTrial::ClearStalePrefs() {
PrefService* prefs = g_browser_process->local_state();
std::vector<std::string> keys_to_clear;
for (auto [key, trial_name] :
prefs->GetDict(prefs::kReadAloudSyntheticTrials)) {
std::string_view feature;
if (!GetFeatureNameFromKey(key, &feature)) {
continue;
}
base::FieldTrial* trial =
base::FeatureList::GetInstance()->GetAssociatedFieldTrialByFeatureName(
feature);
if (!trial || trial->trial_name() != trial_name) {
keys_to_clear.emplace_back(key);
}
}
{
ScopedDictPrefUpdate update(prefs, prefs::kReadAloudSyntheticTrials);
for (const std::string& key : keys_to_clear) {
update->Remove(key);
}
}
}
// static
std::unique_ptr<SyntheticTrial> SyntheticTrial::Create(
const std::string& feature_name,
const std::string& trial_suffix) {
if (feature_name.find(kSeparator) != std::string::npos ||
trial_suffix.find(kSeparator) != std::string::npos) {
return nullptr;
}
base::FieldTrial* trial =
base::FeatureList::GetInstance()->GetAssociatedFieldTrialByFeatureName(
feature_name);
if (!trial) {
return nullptr;
}
return std::make_unique<SyntheticTrial>(feature_name, trial_suffix, trial);
}
SyntheticTrial::SyntheticTrial(const std::string& feature_name,
const std::string& trial_suffix,
base::FieldTrial* base_trial)
: feature_name_(feature_name),
suffix_(trial_suffix),
base_trial_(base_trial) {
DCHECK(!suffix_.empty());
// If this synthetic trial was previously active, reactivate now.
const std::string* stored_base_trial_name =
prefs()->GetDict(prefs::kReadAloudSyntheticTrials).FindString(pref_key());
if (stored_base_trial_name &&
base_trial_->trial_name() == *stored_base_trial_name) {
Activate();
}
}
void SyntheticTrial::Activate() {
if (synthetic_trial_active_) {
return;
}
const std::string synthetic_trial_name =
base::StrCat({base_trial_->trial_name(), suffix_});
ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
synthetic_trial_name, base_trial_->GetGroupNameWithoutActivation(),
variations::SyntheticTrialAnnotationMode::kCurrentLog);
synthetic_trial_active_ = true;
{
ScopedDictPrefUpdate(prefs(), prefs::kReadAloudSyntheticTrials)
->Set(pref_key(), base_trial_->trial_name());
}
}
std::string SyntheticTrial::pref_key() const {
return base::StrCat({feature_name_, kSeparator, suffix_});
}
PrefService* SyntheticTrial::prefs() {
return g_browser_process->local_state();
}
} // namespace readaloud
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