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| 1 // Copyright (c) 2012 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/metrics/variations_util.h" | |
| 6 | |
| 7 #include <map> | |
| 8 #include <vector> | |
| 9 | |
| 10 #include "base/memory/singleton.h" | |
| 11 #include "base/sha1.h" | |
| 12 #include "base/string16.h" | |
| 13 #include "base/stringprintf.h" | |
| 14 #include "base/sys_byteorder.h" | |
| 15 #include "base/utf_string_conversions.h" | |
| 16 #include "chrome/common/child_process_logging.h" | |
| 17 #include "chrome/common/metrics/variation_ids.h" | |
| 18 | |
| 19 namespace { | |
| 20 | |
| 21 // The internal singleton accessor for the map, used to keep it thread-safe. | |
| 22 class GroupMapAccessor { | |
| 23 public: | |
| 24 // Retrieve the singleton. | |
| 25 static GroupMapAccessor* GetInstance() { | |
| 26 return Singleton<GroupMapAccessor>::get(); | |
| 27 } | |
| 28 | |
| 29 GroupMapAccessor() {} | |
| 30 ~GroupMapAccessor() {} | |
| 31 | |
| 32 // Note that this normally only sets the ID for a group the first time, unless | |
| 33 // |force| is set to true, in which case it will always override it. | |
| 34 void AssociateID(const chrome_variations::SelectedGroupId& group_identifier, | |
| 35 chrome_variations::VariationID id, | |
| 36 const bool force) { | |
| 37 base::AutoLock scoped_lock(lock_); | |
| 38 if (force || | |
| 39 group_to_id_map_.find(group_identifier) == group_to_id_map_.end()) | |
| 40 group_to_id_map_[group_identifier] = id; | |
| 41 } | |
| 42 | |
| 43 chrome_variations::VariationID GetID( | |
| 44 const chrome_variations::SelectedGroupId& group_identifier) { | |
| 45 base::AutoLock scoped_lock(lock_); | |
| 46 GroupToIDMap::const_iterator it = group_to_id_map_.find(group_identifier); | |
| 47 if (it == group_to_id_map_.end()) | |
| 48 return chrome_variations::kEmptyID; | |
| 49 return it->second; | |
| 50 } | |
| 51 | |
| 52 private: | |
| 53 typedef std::map<chrome_variations::SelectedGroupId, | |
| 54 chrome_variations::VariationID, | |
| 55 chrome_variations::SelectedGroupIdCompare> GroupToIDMap; | |
| 56 | |
| 57 base::Lock lock_; | |
| 58 GroupToIDMap group_to_id_map_; | |
| 59 }; | |
| 60 | |
| 61 // Creates unique identifier for the trial by hashing a name string, whether | |
| 62 // it's for the field trial or the group name. | |
| 63 uint32 HashName(const std::string& name) { | |
| 64 // SHA-1 is designed to produce a uniformly random spread in its output space, | |
| 65 // even for nearly-identical inputs. | |
| 66 unsigned char sha1_hash[base::kSHA1Length]; | |
| 67 base::SHA1HashBytes(reinterpret_cast<const unsigned char*>(name.c_str()), | |
| 68 name.size(), | |
| 69 sha1_hash); | |
| 70 | |
| 71 COMPILE_ASSERT(sizeof(uint32) < sizeof(sha1_hash), need_more_data); | |
| 72 uint32 bits; | |
| 73 memcpy(&bits, sha1_hash, sizeof(bits)); | |
| 74 | |
| 75 return base::ByteSwapToLE32(bits); | |
| 76 } | |
| 77 | |
| 78 chrome_variations::SelectedGroupId MakeSelectedGroupId( | |
| 79 const std::string& trial_name, | |
| 80 const std::string& group_name) { | |
| 81 chrome_variations::SelectedGroupId id; | |
| 82 id.name = HashName(trial_name); | |
| 83 id.group = HashName(group_name); | |
| 84 return id; | |
| 85 } | |
| 86 | |
| 87 // Populates |name_group_ids| based on |selected_groups|. | |
| 88 void GetFieldTrialSelectedGroupIdsForSelectedGroups( | |
| 89 const base::FieldTrial::SelectedGroups& selected_groups, | |
| 90 std::vector<chrome_variations::SelectedGroupId>* name_group_ids) { | |
| 91 DCHECK(name_group_ids->empty()); | |
| 92 for (base::FieldTrial::SelectedGroups::const_iterator it = | |
| 93 selected_groups.begin(); it != selected_groups.end(); ++it) { | |
| 94 name_group_ids->push_back(MakeSelectedGroupId(it->trial, it->group)); | |
| 95 } | |
| 96 } | |
| 97 | |
| 98 } // namespace | |
| 99 | |
| 100 namespace chrome_variations { | |
| 101 | |
| 102 void GetFieldTrialSelectedGroupIds( | |
| 103 std::vector<SelectedGroupId>* name_group_ids) { | |
| 104 DCHECK(name_group_ids->empty()); | |
| 105 // A note on thread safety: Since GetFieldTrialSelectedGroups is thread | |
| 106 // safe, and we operate on a separate list of that data, this function is | |
| 107 // technically thread safe as well, with respect to the FieldTriaList data. | |
| 108 base::FieldTrial::SelectedGroups selected_groups; | |
| 109 base::FieldTrialList::GetFieldTrialSelectedGroups(&selected_groups); | |
| 110 GetFieldTrialSelectedGroupIdsForSelectedGroups(selected_groups, | |
| 111 name_group_ids); | |
| 112 } | |
| 113 | |
| 114 void AssociateGoogleVariationID(const std::string& trial_name, | |
| 115 const std::string& group_name, | |
| 116 chrome_variations::VariationID id) { | |
| 117 GroupMapAccessor::GetInstance()->AssociateID( | |
| 118 MakeSelectedGroupId(trial_name, group_name), id, false); | |
| 119 } | |
| 120 | |
| 121 void AssociateGoogleVariationIDForce(const std::string& trial_name, | |
| 122 const std::string& group_name, | |
| 123 chrome_variations::VariationID id) { | |
| 124 GroupMapAccessor::GetInstance()->AssociateID( | |
| 125 MakeSelectedGroupId(trial_name, group_name), id, true); | |
| 126 } | |
| 127 | |
| 128 chrome_variations::VariationID GetGoogleVariationID( | |
| 129 const std::string& trial_name, | |
| 130 const std::string& group_name) { | |
| 131 return GroupMapAccessor::GetInstance()->GetID( | |
| 132 MakeSelectedGroupId(trial_name, group_name)); | |
| 133 } | |
| 134 | |
| 135 void GenerateVariationChunks(const std::vector<string16>& experiments, | |
| 136 std::vector<string16>* chunks) { | |
| 137 string16 current_chunk; | |
| 138 for (size_t i = 0; i < experiments.size(); ++i) { | |
| 139 const size_t needed_length = | |
| 140 (current_chunk.empty() ? 1 : 0) + experiments[i].length(); | |
| 141 if (current_chunk.length() + needed_length > kMaxVariationChunkSize) { | |
| 142 chunks->push_back(current_chunk); | |
| 143 current_chunk = experiments[i]; | |
| 144 } else { | |
| 145 if (!current_chunk.empty()) | |
| 146 current_chunk.push_back(','); | |
| 147 current_chunk += experiments[i]; | |
| 148 } | |
| 149 } | |
| 150 if (!current_chunk.empty()) | |
| 151 chunks->push_back(current_chunk); | |
| 152 } | |
| 153 | |
| 154 void SetChildProcessLoggingVariationList() { | |
| 155 std::vector<SelectedGroupId> name_group_ids; | |
| 156 GetFieldTrialSelectedGroupIds(&name_group_ids); | |
| 157 std::vector<string16> experiment_strings(name_group_ids.size()); | |
| 158 for (size_t i = 0; i < name_group_ids.size(); ++i) { | |
| 159 experiment_strings[i] = UTF8ToUTF16(base::StringPrintf( | |
| 160 "%x-%x", name_group_ids[i].name, name_group_ids[i].group)); | |
| 161 } | |
| 162 child_process_logging::SetExperimentList(experiment_strings); | |
| 163 } | |
| 164 | |
| 165 } // namespace chrome_variations | |
| 166 | |
| 167 // Functions below are exposed for testing explicitly behind this namespace. | |
| 168 // They simply wrap existing functions in this file. | |
| 169 namespace testing { | |
| 170 | |
| 171 void TestGetFieldTrialSelectedGroupIdsForSelectedGroups( | |
| 172 const base::FieldTrial::SelectedGroups& selected_groups, | |
| 173 std::vector<chrome_variations::SelectedGroupId>* name_group_ids) { | |
| 174 ::GetFieldTrialSelectedGroupIdsForSelectedGroups(selected_groups, | |
| 175 name_group_ids); | |
| 176 } | |
| 177 | |
| 178 uint32 TestHashName(const std::string& name) { | |
| 179 return ::HashName(name); | |
| 180 } | |
| 181 | |
| 182 } // namespace testing | |
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Chromium Code Reviews
Issue 10828314:
Move Variations stuff into variations/ directories and add OWNERS files for the variations client t… (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/