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// Copyright 2013 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/variations/variations_seed_processor.h"
#include <map>
#include <vector>
#include "base/command_line.h"
#include "base/metrics/field_trial.h"
#include "base/strings/utf_string_conversions.h"
#include "components/variations/processed_study.h"
#include "components/variations/study_filtering.h"
#include "components/variations/variations_associated_data.h"
namespace variations {
namespace {
// Associates the variations params of |experiment|, if present.
void RegisterExperimentParams(const Study& study,
const Study_Experiment& experiment) {
std::map<std::string, std::string> params;
for (int i = 0; i < experiment.param_size(); ++i) {
if (experiment.param(i).has_name() && experiment.param(i).has_value())
params[experiment.param(i).name()] = experiment.param(i).value();
}
if (!params.empty())
AssociateVariationParams(study.name(), experiment.name(), params);
}
// If there are variation ids associated with |experiment|, register the
// variation ids.
void RegisterVariationIds(const Study_Experiment& experiment,
const std::string& trial_name) {
if (experiment.has_google_web_experiment_id()) {
const VariationID variation_id =
static_cast<VariationID>(experiment.google_web_experiment_id());
AssociateGoogleVariationIDForce(GOOGLE_WEB_PROPERTIES,
trial_name,
experiment.name(),
variation_id);
}
if (experiment.has_google_web_trigger_experiment_id()) {
const VariationID variation_id =
static_cast<VariationID>(experiment.google_web_trigger_experiment_id());
AssociateGoogleVariationIDForce(GOOGLE_WEB_PROPERTIES_TRIGGER,
trial_name,
experiment.name(),
variation_id);
}
if (experiment.has_google_update_experiment_id()) {
const VariationID variation_id =
static_cast<VariationID>(experiment.google_update_experiment_id());
AssociateGoogleVariationIDForce(GOOGLE_UPDATE_SERVICE,
trial_name,
experiment.name(),
variation_id);
}
}
// Executes |callback| on every override defined by |experiment|.
void ApplyUIStringOverrides(
const Study_Experiment& experiment,
const VariationsSeedProcessor::UIStringOverrideCallback& callback) {
for (int i = 0; i < experiment.override_ui_string_size(); ++i) {
const Study_Experiment_OverrideUIString& override =
experiment.override_ui_string(i);
callback.Run(override.name_hash(), base::UTF8ToUTF16(override.value()));
}
}
} // namespace
VariationsSeedProcessor::VariationsSeedProcessor() {
}
VariationsSeedProcessor::~VariationsSeedProcessor() {
}
void VariationsSeedProcessor::CreateTrialsFromSeed(
const VariationsSeed& seed,
const std::string& locale,
const base::Time& reference_date,
const base::Version& version,
Study_Channel channel,
Study_FormFactor form_factor,
const std::string& hardware_class,
const UIStringOverrideCallback& override_callback) {
std::vector<ProcessedStudy> filtered_studies;
FilterAndValidateStudies(seed, locale, reference_date, version, channel,
form_factor, hardware_class, &filtered_studies);
for (size_t i = 0; i < filtered_studies.size(); ++i)
CreateTrialFromStudy(filtered_studies[i], override_callback);
}
void VariationsSeedProcessor::CreateTrialFromStudy(
const ProcessedStudy& processed_study,
const UIStringOverrideCallback& override_callback) {
const Study& study = *processed_study.study();
// Check if any experiments need to be forced due to a command line
// flag. Force the first experiment with an existing flag.
base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
for (int i = 0; i < study.experiment_size(); ++i) {
const Study_Experiment& experiment = study.experiment(i);
if (experiment.has_forcing_flag() &&
command_line->HasSwitch(experiment.forcing_flag())) {
scoped_refptr<base::FieldTrial> trial(
base::FieldTrialList::CreateFieldTrial(study.name(),
experiment.name()));
// If |trial| is NULL, then there might already be a trial forced to a
// different group (e.g. via --force-fieldtrials). Break out of the loop,
// but don't return, so that variation ids and params for the selected
// group will still be picked up.
if (!trial.get())
break;
RegisterExperimentParams(study, experiment);
RegisterVariationIds(experiment, study.name());
if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO) {
trial->group();
// UI Strings can only be overridden from ACTIVATION_AUTO experiments.
ApplyUIStringOverrides(experiment, override_callback);
}
DVLOG(1) << "Trial " << study.name() << " forced by flag: "
<< experiment.forcing_flag();
return;
}
}
uint32 randomization_seed = 0;
base::FieldTrial::RandomizationType randomization_type =
base::FieldTrial::SESSION_RANDOMIZED;
if (study.has_consistency() &&
study.consistency() == Study_Consistency_PERMANENT) {
randomization_type = base::FieldTrial::ONE_TIME_RANDOMIZED;
if (study.has_randomization_seed())
randomization_seed = study.randomization_seed();
}
// The trial is created without specifying an expiration date because the
// expiration check in field_trial.cc is based on the build date. Instead,
// the expiration check using |reference_date| is done explicitly below.
scoped_refptr<base::FieldTrial> trial(
base::FieldTrialList::FactoryGetFieldTrialWithRandomizationSeed(
study.name(), processed_study.total_probability(),
study.default_experiment_name(),
base::FieldTrialList::kNoExpirationYear, 1, 1, randomization_type,
randomization_seed, NULL));
bool has_overrides = false;
for (int i = 0; i < study.experiment_size(); ++i) {
const Study_Experiment& experiment = study.experiment(i);
RegisterExperimentParams(study, experiment);
// Groups with forcing flags have probability 0 and will never be selected.
// Therefore, there's no need to add them to the field trial.
if (experiment.has_forcing_flag())
continue;
if (experiment.name() != study.default_experiment_name())
trial->AppendGroup(experiment.name(), experiment.probability_weight());
RegisterVariationIds(experiment, study.name());
has_overrides = has_overrides || experiment.override_ui_string_size() > 0;
}
trial->SetForced();
if (processed_study.is_expired()) {
trial->Disable();
} else if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO) {
const std::string& group_name = trial->group_name();
// Don't try to apply overrides if none of the experiments in this study had
// any.
if (!has_overrides)
return;
// UI Strings can only be overridden from ACTIVATION_AUTO experiments.
int experiment_index = processed_study.GetExperimentIndexByName(group_name);
// The field trial was defined from |study|, so the active experiment's name
// must be in the |study|.
DCHECK_NE(-1, experiment_index);
ApplyUIStringOverrides(study.experiment(experiment_index),
override_callback);
}
}
} // namespace variations
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