// 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 "chrome/common/variations/experiment_labels.h"
#include <vector>
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "chrome/installer/util/google_update_experiment_util.h"
#include "components/variations/variations_associated_data.h"
namespace chrome_variations {
namespace {
const char kVariationPrefix[] = "CrVar";
// This method builds a single experiment label for a Chrome Variation,
// including a timestamp that is a year in the future from |current_time|. Since
// multiple headers can be transmitted, |count| is a number that is appended
// after the label key to differentiate the labels.
base::string16 CreateSingleExperimentLabel(int count, VariationID id,
const base::Time& current_time) {
// Build the parts separately so they can be validated.
const base::string16 key =
base::ASCIIToUTF16(kVariationPrefix) + base::IntToString16(count);
DCHECK_LE(key.size(), 8U);
const base::string16 value = base::IntToString16(id);
DCHECK_LE(value.size(), 8U);
base::string16 label(key);
label += base::ASCIIToUTF16("=");
label += value;
label += base::ASCIIToUTF16("|");
label += installer::BuildExperimentDateString(current_time);
return label;
}
} // namespace
base::string16 BuildGoogleUpdateExperimentLabel(
const base::FieldTrial::ActiveGroups& active_groups) {
base::string16 experiment_labels;
int counter = 0;
const base::Time current_time(base::Time::Now());
// Find all currently active VariationIDs associated with Google Update.
for (base::FieldTrial::ActiveGroups::const_iterator it =
active_groups.begin(); it != active_groups.end(); ++it) {
const VariationID id = GetGoogleVariationID(GOOGLE_UPDATE_SERVICE,
it->trial_name, it->group_name);
if (id == EMPTY_ID)
continue;
if (!experiment_labels.empty())
experiment_labels += google_update::kExperimentLabelSeparator;
experiment_labels += CreateSingleExperimentLabel(++counter, id,
current_time);
}
return experiment_labels;
}
base::string16 ExtractNonVariationLabels(const base::string16& labels) {
// First, split everything by the label separator.
std::vector<base::string16> entries;
base::SplitString(labels, google_update::kExperimentLabelSeparator, &entries);
// For each label, keep the ones that do not look like a Variations label.
base::string16 non_variation_labels;
for (std::vector<base::string16>::const_iterator it = entries.begin();
it != entries.end(); ++it) {
if (it->empty() ||
StartsWith(*it, base::ASCIIToUTF16(kVariationPrefix), false)) {
continue;
}
// Dump the whole thing, including the timestamp.
if (!non_variation_labels.empty())
non_variation_labels += google_update::kExperimentLabelSeparator;
non_variation_labels += *it;
}
return non_variation_labels;
}
base::string16 CombineExperimentLabels(const base::string16& variation_labels,
const base::string16& other_labels) {
const base::string16 separator(1, google_update::kExperimentLabelSeparator);
DCHECK(!StartsWith(variation_labels, separator, false));
DCHECK(!EndsWith(variation_labels, separator, false));
DCHECK(!StartsWith(other_labels, separator, false));
DCHECK(!EndsWith(other_labels, separator, false));
// Note that if either label is empty, a separator is not necessary.
base::string16 combined_labels = other_labels;
if (!other_labels.empty() && !variation_labels.empty())
combined_labels += google_update::kExperimentLabelSeparator;
combined_labels += variation_labels;
return combined_labels;
}
} // namespace chrome_variations