1 // Copyright 2013 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 "components/variations/processed_study.h"
6
7 #include <set>
8 #include <string>
9
10 #include "base/logging.h"
11 #include "base/version.h"
12 #include "components/variations/proto/study.pb.h"
13
14 namespace variations {
15
16 namespace {
17
18 // Validates the sanity of |study| and computes the total probability and
19 // whether all assignments are to a single group.
ValidateStudyAndComputeTotalProbability(const Study & study,base::FieldTrial::Probability * total_probability,bool * all_assignments_to_one_group,std::vector<std::string> * associated_features)20 bool ValidateStudyAndComputeTotalProbability(
21 const Study& study,
22 base::FieldTrial::Probability* total_probability,
23 bool* all_assignments_to_one_group,
24 std::vector<std::string>* associated_features) {
25 if (study.filter().has_min_version() &&
26 !base::Version::IsValidWildcardString(study.filter().min_version())) {
27 DVLOG(1) << study.name() << " has invalid min version: "
28 << study.filter().min_version();
29 return false;
30 }
31 if (study.filter().has_max_version() &&
32 !base::Version::IsValidWildcardString(study.filter().max_version())) {
33 DVLOG(1) << study.name() << " has invalid max version: "
34 << study.filter().max_version();
35 return false;
36 }
37
38 const std::string& default_group_name = study.default_experiment_name();
39 base::FieldTrial::Probability divisor = 0;
40
41 bool multiple_assigned_groups = false;
42 bool found_default_group = false;
43
44 std::set<std::string> experiment_names;
45 std::set<std::string> features_to_associate;
46
47 for (int i = 0; i < study.experiment_size(); ++i) {
48 const Study_Experiment& experiment = study.experiment(i);
49 if (experiment.name().empty()) {
50 DVLOG(1) << study.name() << " is missing experiment " << i << " name";
51 return false;
52 }
53 if (!experiment_names.insert(experiment.name()).second) {
54 DVLOG(1) << study.name() << " has a repeated experiment name "
55 << study.experiment(i).name();
56 return false;
57 }
58
59 // Note: This checks for ACTIVATE_ON_QUERY, since there is no reason to
60 // have this association with ACTIVATE_ON_STARTUP (where the trial starts
61 // active), as well as allowing flexibility to disable this behavior in the
62 // future from the server by introducing a new activation type.
63 if (study.activation_type() == Study_ActivationType_ACTIVATE_ON_QUERY) {
64 const auto& features = experiment.feature_association();
65 for (int i = 0; i < features.enable_feature_size(); ++i) {
66 features_to_associate.insert(features.enable_feature(i));
67 }
68 for (int i = 0; i < features.disable_feature_size(); ++i) {
69 features_to_associate.insert(features.disable_feature(i));
70 }
71 }
72
73 if (!experiment.has_forcing_flag() && experiment.probability_weight() > 0) {
74 // If |divisor| is not 0, there was at least one prior non-zero group.
75 if (divisor != 0)
76 multiple_assigned_groups = true;
77 divisor += experiment.probability_weight();
78 }
79 if (study.experiment(i).name() == default_group_name)
80 found_default_group = true;
81 }
82
83 // Specifying a default experiment is optional, so finding it in the
84 // experiment list is only required when it is specified.
85 if (!study.default_experiment_name().empty() && !found_default_group) {
86 DVLOG(1) << study.name() << " is missing default experiment ("
87 << study.default_experiment_name() << ") in its experiment list";
88 // The default group was not found in the list of groups. This study is not
89 // valid.
90 return false;
91 }
92
93 // Ensure that groups that don't explicitly enable/disable any features get
94 // associated with all features in the study (i.e. so "Default" group gets
95 // reported).
96 if (!features_to_associate.empty()) {
97 associated_features->insert(associated_features->end(),
98 features_to_associate.begin(),
99 features_to_associate.end());
100 }
101
102 *total_probability = divisor;
103 *all_assignments_to_one_group = !multiple_assigned_groups;
104 return true;
105 }
106
107
108 } // namespace
109
110 // static
111 const char ProcessedStudy::kGenericDefaultExperimentName[] =
112 "VariationsDefaultExperiment";
113
ProcessedStudy()114 ProcessedStudy::ProcessedStudy() {}
115
116 ProcessedStudy::ProcessedStudy(const ProcessedStudy& other) = default;
117
~ProcessedStudy()118 ProcessedStudy::~ProcessedStudy() {
119 }
120
Init(const Study * study,bool is_expired)121 bool ProcessedStudy::Init(const Study* study, bool is_expired) {
122 base::FieldTrial::Probability total_probability = 0;
123 bool all_assignments_to_one_group = false;
124 std::vector<std::string> associated_features;
125 if (!ValidateStudyAndComputeTotalProbability(*study, &total_probability,
126 &all_assignments_to_one_group,
127 &associated_features)) {
128 return false;
129 }
130
131 study_ = study;
132 is_expired_ = is_expired;
133 total_probability_ = total_probability;
134 all_assignments_to_one_group_ = all_assignments_to_one_group;
135 associated_features_.swap(associated_features);
136 return true;
137 }
138
GetExperimentIndexByName(const std::string & name) const139 int ProcessedStudy::GetExperimentIndexByName(const std::string& name) const {
140 for (int i = 0; i < study_->experiment_size(); ++i) {
141 if (study_->experiment(i).name() == name)
142 return i;
143 }
144
145 return -1;
146 }
147
GetDefaultExperimentName() const148 const char* ProcessedStudy::GetDefaultExperimentName() const {
149 if (study_->default_experiment_name().empty())
150 return kGenericDefaultExperimentName;
151
152 return study_->default_experiment_name().c_str();
153 }
154
155 // static
ValidateAndAppendStudy(const Study * study,bool is_expired,std::vector<ProcessedStudy> * processed_studies)156 bool ProcessedStudy::ValidateAndAppendStudy(
157 const Study* study,
158 bool is_expired,
159 std::vector<ProcessedStudy>* processed_studies) {
160 ProcessedStudy processed_study;
161 if (processed_study.Init(study, is_expired)) {
162 processed_studies->push_back(processed_study);
163 return true;
164 }
165 return false;
166 }
167
168 } // namespace variations
169