components/variations/processed_study.cc

   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/version.h"
  11 #include "components/variations/proto/study.pb.h"
  12
  13 namespace variations {
  14
  15 namespace {
  16
  17 // Validates the sanity of |study| and computes the total probability and
  18 // whether all assignments are to a single group.
  19 bool ValidateStudyAndComputeTotalProbability(
  20     const Study& study,
  21     base::FieldTrial::Probability* total_probability,
  22     bool* all_assignments_to_one_group) {
  23   // At the moment, a missing default_experiment_name makes the study invalid.
  24   if (study.default_experiment_name().empty()) {
  25     DVLOG(1) << study.name() << " has no default experiment defined.";
  26     return false;
  27   }
  28   if (study.filter().has_min_version() &&
  29       !Version::IsValidWildcardString(study.filter().min_version())) {
  30     DVLOG(1) << study.name() << " has invalid min version: "
  31              << study.filter().min_version();
  32     return false;
  33   }
  34   if (study.filter().has_max_version() &&
  35       !Version::IsValidWildcardString(study.filter().max_version())) {
  36     DVLOG(1) << study.name() << " has invalid max version: "
  37              << study.filter().max_version();
  38     return false;
  39   }
  40
  41   const std::string& default_group_name = study.default_experiment_name();
  42   base::FieldTrial::Probability divisor = 0;
  43
  44   bool multiple_assigned_groups = false;
  45   bool found_default_group = false;
  46   std::set<std::string> experiment_names;
  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     if (!experiment.has_forcing_flag() && experiment.probability_weight() > 0) {
  60       // If |divisor| is not 0, there was at least one prior non-zero group.
  61       if (divisor != 0)
  62         multiple_assigned_groups = true;
  63       divisor += experiment.probability_weight();
  64     }
  65     if (study.experiment(i).name() == default_group_name)
  66       found_default_group = true;
  67   }
  68
  69   if (!found_default_group) {
  70     DVLOG(1) << study.name() << " is missing default experiment in its "
  71              << "experiment list";
  72     // The default group was not found in the list of groups. This study is not
  73     // valid.
  74     return false;
  75   }
  76
  77   *total_probability = divisor;
  78   *all_assignments_to_one_group = !multiple_assigned_groups;
  79   return true;
  80 }
  81
  82
  83 }  // namespace
  84
  85 ProcessedStudy::ProcessedStudy()
  86     : study_(NULL),
  87       total_probability_(0),
  88       all_assignments_to_one_group_(false),
  89       is_expired_(false) {
  90 }
  91
  92 ProcessedStudy::~ProcessedStudy() {
  93 }
  94
  95 bool ProcessedStudy::Init(const Study* study, bool is_expired) {
  96   base::FieldTrial::Probability total_probability = 0;
  97   bool all_assignments_to_one_group = false;
  98   if (!ValidateStudyAndComputeTotalProbability(*study, &total_probability,
  99                                                &all_assignments_to_one_group)) {
 100     return false;
 101   }
 102
 103   study_ = study;
 104   is_expired_ = is_expired;
 105   total_probability_ = total_probability;
 106   all_assignments_to_one_group_ = all_assignments_to_one_group;
 107   return true;
 108 }
 109
 110 int ProcessedStudy::GetExperimentIndexByName(const std::string& name) const {
 111   for (int i = 0; i < study_->experiment_size(); ++i) {
 112     if (study_->experiment(i).name() == name)
 113       return i;
 114   }
 115
 116   return -1;
 117 }
 118
 119 // static
 120 bool ProcessedStudy::ValidateAndAppendStudy(
 121     const Study* study,
 122     bool is_expired,
 123     std::vector<ProcessedStudy>* processed_studies) {
 124   ProcessedStudy processed_study;
 125   if (processed_study.Init(study, is_expired)) {
 126     processed_studies->push_back(processed_study);
 127     return true;
 128   }
 129   return false;
 130 }
 131
 132 }  // namespace variations