Lock scheme #8: Introduced the new locking scheme

webrtc/modules/audio_processing/echo_cancellation_impl.h

 /*
  *  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.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_ECHO_CANCELLATION_IMPL_H_
 #define WEBRTC_MODULES_AUDIO_PROCESSING_ECHO_CANCELLATION_IMPL_H_
 
+#include "webrtc/base/criticalsection.h"
 #include "webrtc/base/scoped_ptr.h"
 #include "webrtc/base/thread_checker.h"
 #include "webrtc/common_audio/swap_queue.h"
 #include "webrtc/modules/audio_processing/include/audio_processing.h"
 #include "webrtc/modules/audio_processing/processing_component.h"
 
 namespace webrtc {
 
 class AudioBuffer;
-class CriticalSectionWrapper;
 
 class EchoCancellationImpl : public EchoCancellation,
                              public ProcessingComponent {
  public:
   EchoCancellationImpl(const AudioProcessing* apm,
-                       CriticalSectionWrapper* crit,
+                       rtc::CriticalSection* crit_render,
+                       rtc::CriticalSection* crit_capture,
                        const rtc::ThreadChecker* render_thread_checker);
   virtual ~EchoCancellationImpl();
 
+  // Called holding the render lock.

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

These comments just add noise. Remove. Document your assumptions with
RTC_DCHECKs.

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

After today's discussion, I think this work will merit one more CL chained to
this one. So if ok with you, I will fix this in that CL instead.

   int ProcessRenderAudio(const AudioBuffer* audio);
+  // Called holding the capture lock.
   int ProcessCaptureAudio(AudioBuffer* audio);
 
   // EchoCancellation implementation.
+  // Aquires both the render and capture locks.
   bool is_enabled() const override;
+  // Aquires the capture loc.k

[kwiberg-webrtc, 2015/11/23 22:15:11]

Swap the last two characters.

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

Done.

   int stream_drift_samples() const override;
+  // Aquires the capture lock.
   SuppressionLevel suppression_level() const override;
+  // Aquires the capture lock.
   bool is_drift_compensation_enabled() const override;
 
   // ProcessingComponent implementation.
+  // Called holding both the capture and render locks.
   int Initialize() override;
+  // Conditionally acquires the capture lock.
   void SetExtraOptions(const Config& config) override;
-
+  // Only called from APM. No lock required.
   bool is_delay_agnostic_enabled() const;
+  // Only called from APM. No lock required.
   bool is_extended_filter_enabled() const;
 
   // Reads render side data that has been queued on the render call.
+  // Called holding the capture lock.
   void ReadQueuedRenderData();
 
  private:
   // EchoCancellation implementation.
+  // Aquires both the render and capture locks.
   int Enable(bool enable) override;
+  // Aquires the capture lock.
   int enable_drift_compensation(bool enable) override;
+  // Aquires the capture lock.
   void set_stream_drift_samples(int drift) override;
+  // Aquires the capture lock.
   int set_suppression_level(SuppressionLevel level) override;
+  // Aquires the capture lock.
   int enable_metrics(bool enable) override;
+  // Aquires the capture lock.
   bool are_metrics_enabled() const override;
+  // Conditionally acquires the capture lock.
   bool stream_has_echo() const override;
+  // Aquires the capture lock.
   int GetMetrics(Metrics* metrics) override;
+  // Aquires the capture lock.
   int enable_delay_logging(bool enable) override;
+  // Only called from APM. No lock required.
   bool is_delay_logging_enabled() const override;
+  // Aquires the capture lock.
   int GetDelayMetrics(int* median, int* std) override;
+  // Aquires the capture lock.
   int GetDelayMetrics(int* median,
                       int* std,
                       float* fraction_poor_delays) override;
+  // Only called from APM. No lock required.
   struct AecCore* aec_core() const override;
 
   // ProcessingComponent implementation.
+  // Called holding both the render and capture locks.
   void* CreateHandle() const override;
+  // Called holding both the render and capture locks.
   int InitializeHandle(void* handle) const override;
+  // Called holding both the render and capture locks.
   int ConfigureHandle(void* handle) const override;
+  // Called holding both the render and capture locks.
   void DestroyHandle(void* handle) const override;
+  // Called holding both the render and capture locks.
   int num_handles_required() const override;
+  // Called holding both the render and capture locks.
   int GetHandleError(void* handle) const override;
 
+  // Called holding both the render and capture locks.
   void AllocateRenderQueue();
 
   const AudioProcessing* apm_;
-  CriticalSectionWrapper* crit_;
+  rtc::CriticalSection* const crit_render_;
+  rtc::CriticalSection* const crit_capture_;
   const rtc::ThreadChecker* const render_thread_checker_;
 
   bool drift_compensation_enabled_;
   bool metrics_enabled_;
   SuppressionLevel suppression_level_;
   int stream_drift_samples_;
   bool was_stream_drift_set_;
   bool stream_has_echo_;
   bool delay_logging_enabled_;
   bool extended_filter_enabled_;
   bool delay_agnostic_enabled_;
 
   size_t render_queue_element_max_size_;
   std::vector<float> render_queue_buffer_;
   std::vector<float> capture_queue_buffer_;
+
+  // Lock protection not needed.
   rtc::scoped_ptr<SwapQueue<std::vector<float>, RenderQueueItemVerifier<float>>>
       render_signal_queue_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_ECHO_CANCELLATION_IMPL_H_

[kwiberg-webrtc, 2015/11/23 22:15:11]

It's a serious problem that you aren't able to use the lock annotations here.
But I guess it's the best we'll get without a substantial refactoring (well, an
even more substantial one).

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

Agree! I'm not sure how far the lock annotation reaches, but by experience it
definitely does not reach as far as when pointers are passed to the locks.