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/interface/field_trial.h"
21
22namespace webrtc {
23namespace {
24// Clients of this library have show a clear intent to setup field trials by
25// linking with it. As so try to crash if they forget to call
26// InitFieldTrialsFromString before webrtc tries to access a field trial.
27bool field_trials_initiated_ = false;
28std::map<std::string, std::string> field_trials_;
29}  // namespace
30
31namespace field_trial {
32std::string FindFullName(const std::string& trial_name) {
33  assert(field_trials_initiated_);
34  std::map<std::string, std::string>::const_iterator it =
35      field_trials_.find(trial_name);
36  if (it == field_trials_.end())
37    return std::string();
38  return it->second;
39}
40}  // namespace field_trial
41
42namespace test {
43// Note: this code is copied from src/base/metrics/field_trial.cc since the aim
44// is to mimic chromium --force-fieldtrials.
45void InitFieldTrialsFromString(const std::string& trials_string) {
46  static const char kPersistentStringSeparator = '/';
47
48  // Catch an error if this is called more than once.
49  assert(field_trials_initiated_ == false);
50  field_trials_initiated_ = true;
51
52  if (trials_string.empty()) return;
53
54  size_t next_item = 0;
55  while (next_item < trials_string.length()) {
56    size_t name_end = trials_string.find(kPersistentStringSeparator, next_item);
57    if (name_end == trials_string.npos || next_item == name_end)
58      break;
59    size_t group_name_end = trials_string.find(kPersistentStringSeparator,
60                                               name_end + 1);
61    if (group_name_end == trials_string.npos || name_end + 1 == group_name_end)
62      break;
63    std::string name(trials_string, next_item, name_end - next_item);
64    std::string group_name(trials_string, name_end + 1,
65                           group_name_end - name_end - 1);
66    next_item = group_name_end + 1;
67
68    // Fail if duplicate with different group name.
69    if (field_trials_.find(name) != field_trials_.end() &&
70        field_trials_.find(name)->second != group_name)
71      break;
72
73    field_trials_[name] = group_name;
74
75    // Successfully parsed all field trials from the string.
76    if (next_item == trials_string.length())
77      return;
78  }
79  // LOG does not prints when this is called early on main.
80  fprintf(stderr, "Invalid field trials string.\n");
81
82  // Using abort so it crashs both in debug and release mode.
83  abort();
84}
85}  // namespace test
86}  // namespace webrtc
87