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/*
* Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "webrtc/test/field_trial.h"
#include <algorithm>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <map>
#include <string>
#include "webrtc/system_wrappers/include/field_trial.h"
namespace webrtc {
namespace {
// Clients of this library have show a clear intent to setup field trials by
// linking with it. As so try to crash if they forget to call
// InitFieldTrialsFromString before webrtc tries to access a field trial.
bool field_trials_initiated_ = false;
std::map<std::string, std::string> field_trials_;
} // namespace
namespace field_trial {
std::string FindFullName(const std::string& trial_name) {
assert(field_trials_initiated_);
std::map<std::string, std::string>::const_iterator it =
field_trials_.find(trial_name);
if (it == field_trials_.end())
return std::string();
return it->second;
}
} // namespace field_trial
namespace test {
// Note: this code is copied from src/base/metrics/field_trial.cc since the aim
// is to mimic chromium --force-fieldtrials.
void InitFieldTrialsFromString(const std::string& trials_string) {
static const char kPersistentStringSeparator = '/';
// Catch an error if this is called more than once.
assert(!field_trials_initiated_);
field_trials_initiated_ = true;
if (trials_string.empty())
return;
size_t next_item = 0;
while (next_item < trials_string.length()) {
size_t name_end = trials_string.find(kPersistentStringSeparator, next_item);
if (name_end == trials_string.npos || next_item == name_end)
break;
size_t group_name_end = trials_string.find(kPersistentStringSeparator,
name_end + 1);
if (group_name_end == trials_string.npos || name_end + 1 == group_name_end)
break;
std::string name(trials_string, next_item, name_end - next_item);
std::string group_name(trials_string, name_end + 1,
group_name_end - name_end - 1);
next_item = group_name_end + 1;
// Fail if duplicate with different group name.
if (field_trials_.find(name) != field_trials_.end() &&
field_trials_.find(name)->second != group_name)
break;
field_trials_[name] = group_name;
// Successfully parsed all field trials from the string.
if (next_item == trials_string.length())
return;
}
// Using fprintf as LOG does not print when this is called early in main.
fprintf(stderr, "Invalid field trials string.\n");
// Using abort so it crashes in both debug and release mode.
abort();
}
ScopedFieldTrials::ScopedFieldTrials(const std::string& config)
: previous_field_trials_(field_trials_) {
assert(field_trials_initiated_);
field_trials_initiated_ = false;
field_trials_.clear();
InitFieldTrialsFromString(config);
}
ScopedFieldTrials::~ScopedFieldTrials() {
// Should still be initialized, since InitFieldTrials is called from ctor.
// That's why we don't restore the flag.
assert(field_trials_initiated_);
field_trials_ = previous_field_trials_;
}
} // namespace test
} // namespace webrtc
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