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 #ifndef COMPONENTS_VARIATIONS_VARIATIONS_SEED_SIMULATOR_H_ 6 #define COMPONENTS_VARIATIONS_VARIATIONS_SEED_SIMULATOR_H_ 7 8 #include <string> 9 #include <vector> 10 11 #include "base/compiler_specific.h" 12 #include "base/gtest_prod_util.h" 13 #include "base/metrics/field_trial.h" 14 #include "base/version.h" 15 #include "components/variations/proto/study.pb.h" 16 #include "components/variations/proto/variations_seed.pb.h" 17 18 namespace chrome_variations { 19 20 class ProcessedStudy; 21 class VariationsSeed; 22 23 // VariationsSeedSimulator simulates the result of creating a set of studies 24 // and detecting which studies would result in group changes. 25 class VariationsSeedSimulator { 26 public: 27 // The result of variations seed simulation, counting the number of experiment 28 // group changes of each type that are expected to occur on a restart with the 29 // seed. 30 struct Result { 31 // The number of expected group changes that do not fall into any special 32 // category. This is a lower bound due to session randomized studies. 33 int normal_group_change_count; 34 35 // The number of expected group changes that fall in the category of killed 36 // experiments that should trigger the "best effort" restart mechanism. 37 int kill_best_effort_group_change_count; 38 39 // The number of expected group changes that fall in the category of killed 40 // experiments that should trigger the "critical" restart mechanism. 41 int kill_critical_group_change_count; 42 43 Result(); 44 ~Result(); 45 }; 46 47 // Creates the simulator with the given entropy |provider|. 48 explicit VariationsSeedSimulator( 49 const base::FieldTrial::EntropyProvider& provider); 50 virtual ~VariationsSeedSimulator(); 51 52 // Computes differences between the current process' field trial state and 53 // the result of evaluating |seed| with the given parameters. Returns the 54 // results of the simulation as a set of expected group change counts of each 55 // type. 56 Result SimulateSeedStudies(const VariationsSeed& seed, 57 const std::string& locale, 58 const base::Time& reference_date, 59 const base::Version& version, 60 Study_Channel channel, 61 Study_FormFactor form_factor, 62 const std::string& hardware_class); 63 64 private: 65 friend class VariationsSeedSimulatorTest; 66 67 enum ChangeType { 68 NO_CHANGE, 69 CHANGED, 70 CHANGED_KILL_BEST_EFFORT, 71 CHANGED_KILL_CRITICAL, 72 }; 73 74 // Computes differences between the current process' field trial state and 75 // the result of evaluating the |processed_studies| list. It is expected that 76 // |processed_studies| have already been filtered and only contain studies 77 // that apply to the configuration being simulated. Returns the results of the 78 // simulation as a set of expected group change counts of each type. 79 Result ComputeDifferences( 80 const std::vector<ProcessedStudy>& processed_studies); 81 82 // Maps proto enum |type| to a ChangeType. 83 ChangeType ConvertExperimentTypeToChangeType(Study_Experiment_Type type); 84 85 // For the given |processed_study| with PERMANENT consistency, simulates group 86 // assignment and returns a corresponding ChangeType if the result differs 87 // from that study's group in the current process. 88 ChangeType PermanentStudyGroupChanged(const ProcessedStudy& processed_study, 89 const std::string& selected_group); 90 91 // For the given |processed_study| with SESSION consistency, determines if 92 // there are enough changes in the study config that restarting will result 93 // in a guaranteed different group assignment (or different params) and 94 // returns the corresponding ChangeType. 95 ChangeType SessionStudyGroupChanged(const ProcessedStudy& filtered_study, 96 const std::string& selected_group); 97 98 const base::FieldTrial::EntropyProvider& entropy_provider_; 99 100 DISALLOW_COPY_AND_ASSIGN(VariationsSeedSimulator); 101 }; 102 103 } // namespace chrome_variations 104 105 #endif // COMPONENTS_VARIATIONS_VARIATIONS_SEED_SIMULATOR_H_ 106