Lock scheme #8: Introduced the new locking scheme

webrtc/modules/audio_processing/gain_control_impl.cc

 /*
  *  Copyright (c) 2012 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/modules/audio_processing/gain_control_impl.h"
 
 #include <assert.h>
 
 #include "webrtc/modules/audio_processing/audio_buffer.h"
 #include "webrtc/modules/audio_processing/agc/legacy/gain_control.h"
-#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
 
 namespace webrtc {
 
 typedef void Handle;
 
 namespace {
 int16_t MapSetting(GainControl::Mode mode) {
   switch (mode) {
     case GainControl::kAdaptiveAnalog:
       return kAgcModeAdaptiveAnalog;
@@ skipping 10 matching lines @@
 static const size_t kMaxAllowedValuesOfSamplesPerFrame = 160;
 // Maximum number of frames to buffer in the render queue.
 // TODO(peah): Decrease this once we properly handle hugely unbalanced
 // reverse and forward call numbers.
 static const size_t kMaxNumFramesToBuffer = 100;
 
 }  // namespace
 
 GainControlImpl::GainControlImpl(
     const AudioProcessing* apm,
-    CriticalSectionWrapper* crit,
+    rtc::CriticalSection* crit_render,
+    rtc::CriticalSection* crit_capture,
     const rtc::ThreadChecker* render_thread_checker,
     const rtc::ThreadChecker* capture_thread_checker)
     : ProcessingComponent(),
       apm_(apm),
-      crit_(crit),
+      crit_render_(crit_render),
+      crit_capture_(crit_capture),
       render_thread_checker_(render_thread_checker),
       capture_thread_checker_(capture_thread_checker),
       mode_(kAdaptiveAnalog),
       minimum_capture_level_(0),
       maximum_capture_level_(255),
       limiter_enabled_(true),
       target_level_dbfs_(3),
       compression_gain_db_(9),
       analog_capture_level_(0),
       was_analog_level_set_(false),
@@ skipping 20 matching lines @@
       return GetHandleError(my_handle);
 
     // Buffer the samples in the render queue.
     render_queue_buffer_.insert(
         render_queue_buffer_.end(), audio->mixed_low_pass_data(),
         (audio->mixed_low_pass_data() + audio->num_frames_per_band()));
   }
 
   // Insert the samples into the queue.
   if (!render_signal_queue_->Insert(&render_queue_buffer_)) {
-    ReadQueuedRenderData();
+    // The data queue is full and needs to be emptied.
+    {
+      rtc::CritScope cs_capture(crit_capture_);
+      ReadQueuedRenderData();
+    }
 
     // Retry the insert (should always work).
     RTC_DCHECK_EQ(render_signal_queue_->Insert(&render_queue_buffer_), true);
   }
 
   return apm_->kNoError;
 }
 
 // Read chunks of data that were received and queued on the render side from
 // a queue. All the data chunks are buffered into the farend signal of the AGC.
@@ skipping 115 matching lines @@
     analog_capture_level_ /= num_handles();
   }
 
   was_analog_level_set_ = false;
   return apm_->kNoError;
 }
 
 // TODO(ajm): ensure this is called under kAdaptiveAnalog.
 int GainControlImpl::set_stream_analog_level(int level) {
   RTC_DCHECK(capture_thread_checker_->CalledOnValidThread());
-  CriticalSectionScoped crit_scoped(crit_);
+
+  rtc::CritScope cs(crit_capture_);
   was_analog_level_set_ = true;
   if (level < minimum_capture_level_ || level > maximum_capture_level_) {
     return apm_->kBadParameterError;
   }
   analog_capture_level_ = level;
 
   return apm_->kNoError;
 }
 
 int GainControlImpl::stream_analog_level() {
+  rtc::CritScope cs(crit_capture_);
   RTC_DCHECK(capture_thread_checker_->CalledOnValidThread());
   // TODO(ajm): enable this assertion?
   //assert(mode_ == kAdaptiveAnalog);
 
   return analog_capture_level_;
 }
 
 int GainControlImpl::Enable(bool enable) {
-  CriticalSectionScoped crit_scoped(crit_);
+  rtc::CritScope cs_render(crit_render_);
+  rtc::CritScope cs(crit_capture_);

[the sun, 2015/11/23 21:36:05]

Why do you sometimes use "cs_capture", and sometimes "cs"?

[peah-webrtc, 2015/11/24 21:42:24]

The scheme is to only use cs, when there is only one critical section active
(one lock acquired), and if two critical sections are active
cs_render/cs_capture is used to distinguish between them. But there clearly was
a miss here on that. Please let me know if you find any other place where that
happened!

Done.

   return EnableComponent(enable);
 }
 
 bool GainControlImpl::is_enabled() const {
+  rtc::CritScope cs(crit_capture_);
   return is_component_enabled();
 }
 
 int GainControlImpl::set_mode(Mode mode) {
-  CriticalSectionScoped crit_scoped(crit_);
+  rtc::CritScope cs_render(crit_render_);
+  rtc::CritScope cs_capture(crit_capture_);
   if (MapSetting(mode) == -1) {
     return apm_->kBadParameterError;
   }
 
   mode_ = mode;
   return Initialize();
 }
 
 GainControl::Mode GainControlImpl::mode() const {
+  rtc::CritScope cs(crit_capture_);
   return mode_;
 }
 
 int GainControlImpl::set_analog_level_limits(int minimum,
                                              int maximum) {
-  CriticalSectionScoped crit_scoped(crit_);
+  rtc::CritScope cs(crit_capture_);
   if (minimum < 0) {
     return apm_->kBadParameterError;
   }
 
   if (maximum > 65535) {
     return apm_->kBadParameterError;
   }
 
   if (maximum < minimum) {
     return apm_->kBadParameterError;
   }
 
   minimum_capture_level_ = minimum;
   maximum_capture_level_ = maximum;
 
   return Initialize();
 }
 
 int GainControlImpl::analog_level_minimum() const {
+  rtc::CritScope cs(crit_capture_);
   return minimum_capture_level_;
 }
 
 int GainControlImpl::analog_level_maximum() const {
+  rtc::CritScope cs(crit_capture_);
   return maximum_capture_level_;
 }
 
 bool GainControlImpl::stream_is_saturated() const {
+  rtc::CritScope cs(crit_capture_);
   return stream_is_saturated_;
 }
 
 int GainControlImpl::set_target_level_dbfs(int level) {
-  CriticalSectionScoped crit_scoped(crit_);
+  rtc::CritScope cs(crit_capture_);
   if (level > 31 || level < 0) {
     return apm_->kBadParameterError;
   }
 
   target_level_dbfs_ = level;
   return Configure();
 }
 
 int GainControlImpl::target_level_dbfs() const {
+  rtc::CritScope cs(crit_capture_);
   return target_level_dbfs_;
 }
 
 int GainControlImpl::set_compression_gain_db(int gain) {
-  CriticalSectionScoped crit_scoped(crit_);
+  rtc::CritScope cs(crit_capture_);
   if (gain < 0 || gain > 90) {
     return apm_->kBadParameterError;
   }
 
   compression_gain_db_ = gain;
   return Configure();
 }
 
 int GainControlImpl::compression_gain_db() const {
+  rtc::CritScope cs(crit_capture_);
   return compression_gain_db_;
 }
 
 int GainControlImpl::enable_limiter(bool enable) {
-  CriticalSectionScoped crit_scoped(crit_);
+  rtc::CritScope cs(crit_capture_);
   limiter_enabled_ = enable;
   return Configure();
 }
 
 bool GainControlImpl::is_limiter_enabled() const {
+  rtc::CritScope cs(crit_capture_);
   return limiter_enabled_;
 }
 
 int GainControlImpl::Initialize() {
   int err = ProcessingComponent::Initialize();
   if (err != apm_->kNoError || !is_component_enabled()) {
     return err;
   }
 
   AllocateRenderQueue();
 
   const int n = num_handles();
   RTC_CHECK_GE(n, 0) << "Bad number of handles: " << n;
   capture_levels_.assign(n, analog_capture_level_);
   return apm_->kNoError;
 }
 
 void GainControlImpl::AllocateRenderQueue() {
+  // Only called from within APM, hence no locking is needed.
   const size_t new_render_queue_element_max_size =
       std::max<size_t>(static_cast<size_t>(1),
                        kMaxAllowedValuesOfSamplesPerFrame * num_handles());
 
   if (render_queue_element_max_size_ < new_render_queue_element_max_size) {
     render_queue_element_max_size_ = new_render_queue_element_max_size;
     std::vector<int16_t> template_queue_element(render_queue_element_max_size_);
 
     render_signal_queue_.reset(
         new SwapQueue<std::vector<int16_t>, RenderQueueItemVerifier<int16_t>>(
             kMaxNumFramesToBuffer, template_queue_element,
             RenderQueueItemVerifier<int16_t>(render_queue_element_max_size_)));
 
     render_queue_buffer_.resize(render_queue_element_max_size_);
     capture_queue_buffer_.resize(render_queue_element_max_size_);
   } else {
     render_signal_queue_->Clear();
   }
 }
 
 void* GainControlImpl::CreateHandle() const {
+  // Only called from within APM, hence no locking is needed.
   return WebRtcAgc_Create();
 }
 
 void GainControlImpl::DestroyHandle(void* handle) const {
+  // Only called from within APM, hence no locking is needed.
   WebRtcAgc_Free(static_cast<Handle*>(handle));
 }
 
 int GainControlImpl::InitializeHandle(void* handle) const {
+  // Only called from within APM, hence no locking is needed.
   return WebRtcAgc_Init(static_cast<Handle*>(handle),
                           minimum_capture_level_,
                           maximum_capture_level_,
                           MapSetting(mode_),
                           apm_->proc_sample_rate_hz());
 }
 
 int GainControlImpl::ConfigureHandle(void* handle) const {
+  // Only called from within APM, hence no locking is needed.
   WebRtcAgcConfig config;
   // TODO(ajm): Flip the sign here (since AGC expects a positive value) if we
   //            change the interface.
   //assert(target_level_dbfs_ <= 0);
   //config.targetLevelDbfs = static_cast<int16_t>(-target_level_dbfs_);
   config.targetLevelDbfs = static_cast<int16_t>(target_level_dbfs_);
   config.compressionGaindB =
       static_cast<int16_t>(compression_gain_db_);
   config.limiterEnable = limiter_enabled_;
 
   return WebRtcAgc_set_config(static_cast<Handle*>(handle), config);
 }
 
 int GainControlImpl::num_handles_required() const {
+  // Only called from within APM, hence no locking is needed.
   return apm_->num_output_channels();
 }
 
 int GainControlImpl::GetHandleError(void* handle) const {
+  // Only called from within APM, hence no locking is needed.
   // The AGC has no get_error() function.
   // (Despite listing errors in its interface...)
   assert(handle != NULL);
   return apm_->kUnspecifiedError;
 }
 }  // namespace webrtc