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Replaced thread checker with race checker in AudioMixer.

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This change is due to an incorrect understanding of the threading
model in Chrome. The new AudioMixer has a thread checker to ensure
that mixing is always done from a single thread. Mixing is done on the
Audio Output Thread. When run in Chrome, it can change. Even if the thread
changes, there is never more than one audio thread, and mixing is done
sequentially.

The threading checks and variable access checks are replaced with
rtc::RaceChecker counterparts.

NOTRY=True
BUG=webrtc:6346

Review-Url: https://codereview.webrtc.org/2437913003
Cr-Commit-Position: refs/heads/master@{#14712}
This commit is contained in:
aleloi 2016-10-20 14:23:24 -07:00 committed by Commit bot
parent 161a586b45
commit 920d30bc74
2 changed files with 16 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
webrtc/modules/audio_mixer/audio_mixer_impl.cc
View File

@ -143,7 +143,6 @@ AudioMixerImpl::AudioMixerImpl(std::unique_ptr<AudioProcessing> limiter)
time_stamp_(0),
limiter_(std::move(limiter)) {
SetOutputFrequency(kDefaultFrequency);
thread_checker_.DetachFromThread();
}
AudioMixerImpl::~AudioMixerImpl() {}
@ -189,7 +188,7 @@ void AudioMixerImpl::Mix(int sample_rate,
size_t number_of_channels,
AudioFrame* audio_frame_for_mixing) {
RTC_DCHECK(number_of_channels == 1 || number_of_channels == 2);
RTC_DCHECK_RUN_ON(&thread_checker_);
RTC_DCHECK_RUNS_SERIALIZED(&race_checker_);
if (OutputFrequency() != sample_rate) {
SetOutputFrequency(sample_rate);
@ -229,13 +228,13 @@ void AudioMixerImpl::Mix(int sample_rate,
}
void AudioMixerImpl::SetOutputFrequency(int frequency) {
RTC_DCHECK_RUN_ON(&thread_checker_);
RTC_DCHECK_RUNS_SERIALIZED(&race_checker_);
output_frequency_ = frequency;
sample_size_ = (output_frequency_ * kFrameDurationInMs) / 1000;
}
int AudioMixerImpl::OutputFrequency() const {
RTC_DCHECK_RUN_ON(&thread_checker_);
RTC_DCHECK_RUNS_SERIALIZED(&race_checker_);
return output_frequency_;
}
@ -259,7 +258,7 @@ bool AudioMixerImpl::RemoveSource(Source* audio_source) {
}
AudioFrameList AudioMixerImpl::GetAudioFromSources() {
RTC_DCHECK_RUN_ON(&thread_checker_);
RTC_DCHECK_RUNS_SERIALIZED(&race_checker_);
AudioFrameList result;
std::vector<SourceFrame> audio_source_mixing_data_list;
std::vector<SourceFrame> ramp_list;
@ -312,7 +311,7 @@ AudioFrameList AudioMixerImpl::GetAudioFromSources() {
bool AudioMixerImpl::LimitMixedAudio(AudioFrame* mixed_audio) const {
RTC_DCHECK_RUN_ON(&thread_checker_);
RTC_DCHECK_RUNS_SERIALIZED(&race_checker_);
if (!use_limiter_) {
return true;
}
@ -342,7 +341,7 @@ bool AudioMixerImpl::LimitMixedAudio(AudioFrame* mixed_audio) const {
bool AudioMixerImpl::GetAudioSourceMixabilityStatusForTest(
AudioMixerImpl::Source* audio_source) const {
RTC_DCHECK_RUN_ON(&thread_checker_);
RTC_DCHECK_RUNS_SERIALIZED(&race_checker_);
rtc::CritScope lock(&crit_);
const auto non_anonymous_iter =

20
webrtc/modules/audio_mixer/audio_mixer_impl.h
View File

@ -17,7 +17,7 @@
#include "webrtc/api/audio/audio_mixer.h"
#include "webrtc/base/scoped_ref_ptr.h"
#include "webrtc/base/thread_annotations.h"
#include "webrtc/base/thread_checker.h"
#include "webrtc/base/race_checker.h"
#include "webrtc/modules/audio_processing/include/audio_processing.h"
#include "webrtc/modules/include/module_common_types.h"
#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
@ -83,27 +83,27 @@ class AudioMixerImpl : public AudioMixer {
bool LimitMixedAudio(AudioFrame* mixed_audio) const;
// The critical section lock guards audio source insertion and
// removal, which can be done from any thread. The race checker
// checks that mixing is done sequentially.
rtc::CriticalSection crit_;
rtc::RaceChecker race_checker_;
// The current sample frequency and sample size when mixing.
int output_frequency_ ACCESS_ON(&thread_checker_);
size_t sample_size_ ACCESS_ON(&thread_checker_);
int output_frequency_ GUARDED_BY(race_checker_);
size_t sample_size_ GUARDED_BY(race_checker_);
// List of all audio sources. Note all lists are disjunct
SourceStatusList audio_source_list_ GUARDED_BY(crit_); // May be mixed.
// Determines if we will use a limiter for clipping protection during
// mixing.
bool use_limiter_ ACCESS_ON(&thread_checker_);
bool use_limiter_ GUARDED_BY(race_checker_);
uint32_t time_stamp_ ACCESS_ON(&thread_checker_);
// Ensures that Mix is called from the same thread.
rtc::ThreadChecker thread_checker_;
uint32_t time_stamp_ GUARDED_BY(race_checker_);
// Used for inhibiting saturation in mixing.
std::unique_ptr<AudioProcessing> limiter_ ACCESS_ON(&thread_checker_);
std::unique_ptr<AudioProcessing> limiter_ GUARDED_BY(race_checker_);
RTC_DISALLOW_COPY_AND_ASSIGN(AudioMixerImpl);
};