1 /* 2 * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include "webrtc/test/field_trial.h" 12 13 #include <algorithm> 14 #include <cassert> 15 #include <cstdio> 16 #include <cstdlib> 17 #include <map> 18 #include <string> 19 20 #include "webrtc/system_wrappers/include/field_trial.h" 21 #include "webrtc/system_wrappers/include/field_trial_default.h" 22 23 namespace webrtc { 24 namespace { 25 bool field_trials_initiated_ = false; 26 } // namespace 27 28 namespace test { 29 // Note: this code is copied from src/base/metrics/field_trial.cc since the aim 30 // is to mimic chromium --force-fieldtrials. InitFieldTrialsFromString(const std::string & trials_string)31void InitFieldTrialsFromString(const std::string& trials_string) { 32 static const char kPersistentStringSeparator = '/'; 33 34 // Catch an error if this is called more than once. 35 assert(!field_trials_initiated_); 36 field_trials_initiated_ = true; 37 38 if (trials_string.empty()) 39 return; 40 41 size_t next_item = 0; 42 std::map<std::string, std::string> field_trials; 43 while (next_item < trials_string.length()) { 44 size_t name_end = trials_string.find(kPersistentStringSeparator, next_item); 45 if (name_end == trials_string.npos || next_item == name_end) 46 break; 47 size_t group_name_end = trials_string.find(kPersistentStringSeparator, 48 name_end + 1); 49 if (group_name_end == trials_string.npos || name_end + 1 == group_name_end) 50 break; 51 std::string name(trials_string, next_item, name_end - next_item); 52 std::string group_name(trials_string, name_end + 1, 53 group_name_end - name_end - 1); 54 next_item = group_name_end + 1; 55 56 // Fail if duplicate with different group name. 57 if (field_trials.find(name) != field_trials.end() && 58 field_trials.find(name)->second != group_name) { 59 break; 60 } 61 62 field_trials[name] = group_name; 63 64 // Successfully parsed all field trials from the string. 65 if (next_item == trials_string.length()) { 66 webrtc::field_trial::InitFieldTrialsFromString(trials_string.c_str()); 67 return; 68 } 69 } 70 // Using fprintf as LOG does not print when this is called early in main. 71 fprintf(stderr, "Invalid field trials string.\n"); 72 73 // Using abort so it crashes in both debug and release mode. 74 abort(); 75 } 76 ScopedFieldTrials(const std::string & config)77ScopedFieldTrials::ScopedFieldTrials(const std::string& config) 78 : previous_field_trials_(webrtc::field_trial::GetFieldTrialString()) { 79 assert(field_trials_initiated_); 80 field_trials_initiated_ = false; 81 current_field_trials_ = config; 82 InitFieldTrialsFromString(current_field_trials_); 83 } 84 ~ScopedFieldTrials()85ScopedFieldTrials::~ScopedFieldTrials() { 86 // Should still be initialized, since InitFieldTrials is called from ctor. 87 // That's why we don't restore the flag. 88 assert(field_trials_initiated_); 89 webrtc::field_trial::InitFieldTrialsFromString(previous_field_trials_); 90 } 91 92 } // namespace test 93 } // namespace webrtc 94