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// Copyright 2017 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 "base/metrics/field_trial_params.h"
#include <set>
#include <utility>
#include <vector>
#include "base/feature_list.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/field_trial_param_associator.h"
#include "base/strings/escape.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/stringprintf.h"
namespace base {
std::string UnescapeValue(const std::string& value) {
return UnescapeURLComponent(
value, UnescapeRule::PATH_SEPARATORS |
UnescapeRule::URL_SPECIAL_CHARS_EXCEPT_PATH_SEPARATORS);
}
bool AssociateFieldTrialParams(const std::string& trial_name,
const std::string& group_name,
const FieldTrialParams& params) {
return FieldTrialParamAssociator::GetInstance()->AssociateFieldTrialParams(
trial_name, group_name, params);
}
bool AssociateFieldTrialParamsFromString(
const std::string& params_string,
FieldTrialParamsDecodeStringFunc decode_data_func) {
// Format: Trial1.Group1:k1/v1/k2/v2,Trial2.Group2:k1/v1/k2/v2
std::set<std::pair<std::string, std::string>> trial_groups;
for (StringPiece experiment_group :
SplitStringPiece(params_string, ",", TRIM_WHITESPACE, SPLIT_WANT_ALL)) {
std::vector<StringPiece> experiment = SplitStringPiece(
experiment_group, ":", TRIM_WHITESPACE, SPLIT_WANT_ALL);
if (experiment.size() != 2) {
DLOG(ERROR) << "Experiment and params should be separated by ':'";
return false;
}
std::vector<std::string> group_parts =
SplitString(experiment[0], ".", TRIM_WHITESPACE, SPLIT_WANT_ALL);
if (group_parts.size() != 2) {
DLOG(ERROR) << "Trial and group name should be separated by '.'";
return false;
}
std::vector<std::string> key_values =
SplitString(experiment[1], "/", TRIM_WHITESPACE, SPLIT_WANT_ALL);
if (key_values.size() % 2 != 0) {
DLOG(ERROR) << "Param name and param value should be separated by '/'";
return false;
}
std::string trial = decode_data_func(group_parts[0]);
std::string group = decode_data_func(group_parts[1]);
auto trial_group = std::make_pair(trial, group);
if (trial_groups.find(trial_group) != trial_groups.end()) {
DLOG(ERROR) << StringPrintf(
"A (trial, group) pair listed more than once. (%s, %s)",
trial.c_str(), group.c_str());
return false;
}
trial_groups.insert(trial_group);
std::map<std::string, std::string> params;
for (size_t i = 0; i < key_values.size(); i += 2) {
std::string key = decode_data_func(key_values[i]);
std::string value = decode_data_func(key_values[i + 1]);
params[key] = value;
}
bool result = AssociateFieldTrialParams(trial, group, params);
if (!result) {
DLOG(ERROR) << "Failed to associate field trial params for group \""
<< group << "\" in trial \"" << trial << "\"";
return false;
}
}
return true;
}
bool GetFieldTrialParams(const std::string& trial_name,
FieldTrialParams* params) {
return FieldTrialParamAssociator::GetInstance()->GetFieldTrialParams(
trial_name, params);
}
bool GetFieldTrialParamsByFeature(const Feature& feature,
FieldTrialParams* params) {
if (!FeatureList::IsEnabled(feature))
return false;
FieldTrial* trial = FeatureList::GetFieldTrial(feature);
if (!trial)
return false;
return GetFieldTrialParams(trial->trial_name(), params);
}
std::string GetFieldTrialParamValue(const std::string& trial_name,
const std::string& param_name) {
FieldTrialParams params;
if (GetFieldTrialParams(trial_name, ¶ms)) {
auto it = params.find(param_name);
if (it != params.end())
return it->second;
}
return std::string();
}
std::string GetFieldTrialParamValueByFeature(const Feature& feature,
const std::string& param_name) {
if (!FeatureList::IsEnabled(feature))
return std::string();
FieldTrial* trial = FeatureList::GetFieldTrial(feature);
if (!trial)
return std::string();
return GetFieldTrialParamValue(trial->trial_name(), param_name);
}
int GetFieldTrialParamByFeatureAsInt(const Feature& feature,
const std::string& param_name,
int default_value) {
std::string value_as_string =
GetFieldTrialParamValueByFeature(feature, param_name);
int value_as_int = 0;
if (!StringToInt(value_as_string, &value_as_int)) {
if (!value_as_string.empty()) {
DLOG(WARNING) << "Failed to parse field trial param " << param_name
<< " with string value " << value_as_string
<< " under feature " << feature.name
<< " into an int. Falling back to default value of "
<< default_value;
}
value_as_int = default_value;
}
return value_as_int;
}
double GetFieldTrialParamByFeatureAsDouble(const Feature& feature,
const std::string& param_name,
double default_value) {
std::string value_as_string =
GetFieldTrialParamValueByFeature(feature, param_name);
double value_as_double = 0;
if (!StringToDouble(value_as_string, &value_as_double)) {
if (!value_as_string.empty()) {
DLOG(WARNING) << "Failed to parse field trial param " << param_name
<< " with string value " << value_as_string
<< " under feature " << feature.name
<< " into a double. Falling back to default value of "
<< default_value;
}
value_as_double = default_value;
}
return value_as_double;
}
bool GetFieldTrialParamByFeatureAsBool(const Feature& feature,
const std::string& param_name,
bool default_value) {
std::string value_as_string =
GetFieldTrialParamValueByFeature(feature, param_name);
if (value_as_string == "true")
return true;
if (value_as_string == "false")
return false;
if (!value_as_string.empty()) {
DLOG(WARNING) << "Failed to parse field trial param " << param_name
<< " with string value " << value_as_string
<< " under feature " << feature.name
<< " into a bool. Falling back to default value of "
<< default_value;
}
return default_value;
}
base::TimeDelta GetFieldTrialParamByFeatureAsTimeDelta(
const Feature& feature,
const std::string& param_name,
base::TimeDelta default_value) {
std::string value_as_string =
GetFieldTrialParamValueByFeature(feature, param_name);
if (value_as_string.empty())
return default_value;
base::Optional<base::TimeDelta> ret =
base::TimeDelta::FromString(value_as_string);
if (!ret.has_value()) {
DLOG(WARNING)
<< "Failed to parse field trial param " << param_name
<< " with string value " << value_as_string << " under feature "
<< feature.name
<< " into a base::TimeDelta. Falling back to default value of "
<< default_value;
return default_value;
}
return ret.value();
}
std::string FeatureParam<std::string>::Get() const {
const std::string value = GetFieldTrialParamValueByFeature(*feature, name);
return value.empty() ? default_value : value;
}
double FeatureParam<double>::Get() const {
return GetFieldTrialParamByFeatureAsDouble(*feature, name, default_value);
}
int FeatureParam<int>::Get() const {
return GetFieldTrialParamByFeatureAsInt(*feature, name, default_value);
}
bool FeatureParam<bool>::Get() const {
return GetFieldTrialParamByFeatureAsBool(*feature, name, default_value);
}
base::TimeDelta FeatureParam<base::TimeDelta>::Get() const {
return GetFieldTrialParamByFeatureAsTimeDelta(*feature, name, default_value);
}
void LogInvalidEnumValue(const Feature& feature,
const std::string& param_name,
const std::string& value_as_string,
int default_value_as_int) {
DLOG(WARNING) << "Failed to parse field trial param " << param_name
<< " with string value " << value_as_string << " under feature "
<< feature.name
<< " into an enum. Falling back to default value of "
<< default_value_as_int;
}
} // namespace base
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