Work around data race in TransmitMixer.

webrtc/voice_engine/transmit_mixer.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/voice_engine/transmit_mixer.h"
 
 #include "webrtc/base/format_macros.h"
 #include "webrtc/modules/utility/include/audio_frame_operations.h"
 #include "webrtc/system_wrappers/include/critical_section_wrapper.h"
 #include "webrtc/system_wrappers/include/event_wrapper.h"
 #include "webrtc/system_wrappers/include/logging.h"
 #include "webrtc/system_wrappers/include/trace.h"
 #include "webrtc/voice_engine/channel.h"
 #include "webrtc/voice_engine/channel_manager.h"
 #include "webrtc/voice_engine/include/voe_external_media.h"
 #include "webrtc/voice_engine/statistics.h"
 #include "webrtc/voice_engine/utility.h"
 #include "webrtc/voice_engine/voe_base_impl.h"
 
-#define WEBRTC_ABS(a) (((a) < 0) ? -(a) : (a))
-
 namespace webrtc {
 namespace voe {
 
 // TODO(ajm): The thread safety of this is dubious...
 void
 TransmitMixer::OnPeriodicProcess()
 {
     WEBRTC_TRACE(kTraceStream, kTraceVoice, VoEId(_instanceId, -1),
                  "TransmitMixer::OnPeriodicProcess()");
 
 #if defined(WEBRTC_VOICE_ENGINE_TYPING_DETECTION)
-    if (_typingNoiseWarningPending)
+    bool send_typing_noise_warning = false;
+    bool typing_noise_detected = false;
     {
+      CriticalSectionScoped cs(&_critSect);
+      if (_typingNoiseWarningPending) {
+        send_typing_noise_warning = true;
+        typing_noise_detected = _typingNoiseDetected;
+        _typingNoiseWarningPending = false;
+      }
+    }
+    if (send_typing_noise_warning) {
         CriticalSectionScoped cs(&_callbackCritSect);
-        if (_voiceEngineObserverPtr)
-        {
-            if (_typingNoiseDetected) {
+        if (_voiceEngineObserverPtr) {
+            if (typing_noise_detected) {
                 WEBRTC_TRACE(kTraceInfo, kTraceVoice, VoEId(_instanceId, -1),
                              "TransmitMixer::OnPeriodicProcess() => "
                              "CallbackOnError(VE_TYPING_NOISE_WARNING)");
                 _voiceEngineObserverPtr->CallbackOnError(
                     -1,
                     VE_TYPING_NOISE_WARNING);
             } else {
                 WEBRTC_TRACE(kTraceInfo, kTraceVoice, VoEId(_instanceId, -1),
                              "TransmitMixer::OnPeriodicProcess() => "
                              "CallbackOnError(VE_TYPING_NOISE_OFF_WARNING)");
                 _voiceEngineObserverPtr->CallbackOnError(
                     -1,
                     VE_TYPING_NOISE_OFF_WARNING);
             }
         }
-        _typingNoiseWarningPending = false;
     }
 #endif
 
     bool saturationWarning = false;
     {
       // Modify |_saturationWarning| under lock to avoid conflict with write op
       // in ProcessAudio and also ensure that we don't hold the lock during the
       // callback.
       CriticalSectionScoped cs(&_critSect);
       saturationWarning = _saturationWarning;
@@ skipping 1201 matching lines @@
 #ifdef WEBRTC_VOICE_ENGINE_TYPING_DETECTION
 void TransmitMixer::TypingDetection(bool keyPressed)
 {
   // We let the VAD determine if we're using this feature or not.
   if (_audioFrame.vad_activity_ == AudioFrame::kVadUnknown) {
     return;
   }
 
   bool vadActive = _audioFrame.vad_activity_ == AudioFrame::kVadActive;
   if (_typingDetection.Process(keyPressed, vadActive)) {
+    CriticalSectionScoped cs(&_critSect);
     _typingNoiseWarningPending = true;
     _typingNoiseDetected = true;
   } else {
+    CriticalSectionScoped cs(&_critSect);
     // If there is already a warning pending, do not change the state.
     // Otherwise set a warning pending if last callback was for noise detected.
     if (!_typingNoiseWarningPending && _typingNoiseDetected) {
       _typingNoiseWarningPending = true;
       _typingNoiseDetected = false;
     }
   }
 }
 #endif
 
@@ skipping 33 matching lines @@
 void TransmitMixer::EnableStereoChannelSwapping(bool enable) {
   swap_stereo_channels_ = enable;
 }
 
 bool TransmitMixer::IsStereoChannelSwappingEnabled() {
   return swap_stereo_channels_;
 }
 
 }  // namespace voe
 }  // namespace webrtc