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_ACTIVE_FIELD_TRIALS_H_ 6 #define COMPONENTS_VARIATIONS_ACTIVE_FIELD_TRIALS_H_ 7 8 #include <string> 9 10 #include "base/basictypes.h" 11 #include "base/metrics/field_trial.h" 12 13 namespace variations { 14 15 // The Unique ID of a trial and its active group, where the name and group 16 // identifiers are hashes of the trial and group name strings. 17 struct ActiveGroupId { 18 uint32 name; 19 uint32 group; 20 }; 21 22 // Returns an ActiveGroupId struct for the given trial and group names. 23 ActiveGroupId MakeActiveGroupId(const std::string& trial_name, 24 const std::string& group_name); 25 26 // We need to supply a Compare class for templates since ActiveGroupId is a 27 // user-defined type. 28 struct ActiveGroupIdCompare { operatorActiveGroupIdCompare29 bool operator() (const ActiveGroupId& lhs, const ActiveGroupId& rhs) const { 30 // The group and name fields are just SHA-1 Hashes, so we just need to treat 31 // them as IDs and do a less-than comparison. We test group first, since 32 // name is more likely to collide. 33 if (lhs.group != rhs.group) 34 return lhs.group < rhs.group; 35 return lhs.name < rhs.name; 36 } 37 }; 38 39 // Fills the supplied vector |name_group_ids| (which must be empty when called) 40 // with unique ActiveGroupIds for each Field Trial that has a chosen group. 41 // Field Trials for which a group has not been chosen yet are NOT returned in 42 // this list. 43 void GetFieldTrialActiveGroupIds(std::vector<ActiveGroupId>* name_group_ids); 44 45 // Fills the supplied vector |output| (which must be empty when called) with 46 // unique string representations of ActiveGroupIds for each Field Trial that 47 // has a chosen group. The strings are formatted as "<TrialName>-<GroupName>", 48 // with the names as hex strings. Field Trials for which a group has not been 49 // chosen yet are NOT returned in this list. 50 void GetFieldTrialActiveGroupIdsAsStrings(std::vector<std::string>* output); 51 52 // Expose some functions for testing. These functions just wrap functionality 53 // that is implemented above. 54 namespace testing { 55 56 void TestGetFieldTrialActiveGroupIds( 57 const base::FieldTrial::ActiveGroups& active_groups, 58 std::vector<ActiveGroupId>* name_group_ids); 59 60 } // namespace testing 61 62 } // namespace variations 63 64 #endif // COMPONENTS_VARIATIONS_ACTIVE_FIELD_TRIALS_H_ 65