1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "chrome/common/variations/experiment_labels.h" 6 7 #include <vector> 8 9 #include "base/logging.h" 10 #include "base/strings/string_number_conversions.h" 11 #include "base/strings/string_split.h" 12 #include "base/strings/string_util.h" 13 #include "base/strings/utf_string_conversions.h" 14 #include "chrome/installer/util/google_update_experiment_util.h" 15 #include "components/variations/variations_associated_data.h" 16 17 namespace chrome_variations { 18 19 namespace { 20 21 const char kVariationPrefix[] = "CrVar"; 22 23 // This method builds a single experiment label for a Chrome Variation, 24 // including a timestamp that is a year in the future from |current_time|. Since 25 // multiple headers can be transmitted, |count| is a number that is appended 26 // after the label key to differentiate the labels. 27 base::string16 CreateSingleExperimentLabel(int count, 28 variations::VariationID id, 29 const base::Time& current_time) { 30 // Build the parts separately so they can be validated. 31 const base::string16 key = 32 base::ASCIIToUTF16(kVariationPrefix) + base::IntToString16(count); 33 DCHECK_LE(key.size(), 8U); 34 const base::string16 value = base::IntToString16(id); 35 DCHECK_LE(value.size(), 8U); 36 base::string16 label(key); 37 label += base::ASCIIToUTF16("="); 38 label += value; 39 label += base::ASCIIToUTF16("|"); 40 label += installer::BuildExperimentDateString(current_time); 41 return label; 42 } 43 44 } // namespace 45 46 base::string16 BuildGoogleUpdateExperimentLabel( 47 const base::FieldTrial::ActiveGroups& active_groups) { 48 base::string16 experiment_labels; 49 int counter = 0; 50 51 const base::Time current_time(base::Time::Now()); 52 53 // Find all currently active VariationIDs associated with Google Update. 54 for (base::FieldTrial::ActiveGroups::const_iterator it = 55 active_groups.begin(); it != active_groups.end(); ++it) { 56 const variations::VariationID id = 57 variations::GetGoogleVariationID(variations::GOOGLE_UPDATE_SERVICE, 58 it->trial_name, it->group_name); 59 60 if (id == variations::EMPTY_ID) 61 continue; 62 63 if (!experiment_labels.empty()) 64 experiment_labels += google_update::kExperimentLabelSeparator; 65 experiment_labels += CreateSingleExperimentLabel(++counter, id, 66 current_time); 67 } 68 69 return experiment_labels; 70 } 71 72 base::string16 ExtractNonVariationLabels(const base::string16& labels) { 73 // First, split everything by the label separator. 74 std::vector<base::string16> entries; 75 base::SplitString(labels, google_update::kExperimentLabelSeparator, &entries); 76 77 // For each label, keep the ones that do not look like a Variations label. 78 base::string16 non_variation_labels; 79 for (std::vector<base::string16>::const_iterator it = entries.begin(); 80 it != entries.end(); ++it) { 81 if (it->empty() || 82 StartsWith(*it, base::ASCIIToUTF16(kVariationPrefix), false)) { 83 continue; 84 } 85 86 // Dump the whole thing, including the timestamp. 87 if (!non_variation_labels.empty()) 88 non_variation_labels += google_update::kExperimentLabelSeparator; 89 non_variation_labels += *it; 90 } 91 92 return non_variation_labels; 93 } 94 95 base::string16 CombineExperimentLabels(const base::string16& variation_labels, 96 const base::string16& other_labels) { 97 const base::string16 separator(1, google_update::kExperimentLabelSeparator); 98 DCHECK(!StartsWith(variation_labels, separator, false)); 99 DCHECK(!EndsWith(variation_labels, separator, false)); 100 DCHECK(!StartsWith(other_labels, separator, false)); 101 DCHECK(!EndsWith(other_labels, separator, false)); 102 // Note that if either label is empty, a separator is not necessary. 103 base::string16 combined_labels = other_labels; 104 if (!other_labels.empty() && !variation_labels.empty()) 105 combined_labels += google_update::kExperimentLabelSeparator; 106 combined_labels += variation_labels; 107 return combined_labels; 108 } 109 110 } // namespace chrome_variations 111