Less lock acquisitions for AudioMixer.

webrtc/modules/audio_mixer/test/audio_mixer_unittest.cc

 /*
  *  Copyright (c) 2016 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 <cstring>

[ivoc, 2016/08/31 14:34:25]

I think we generally use the <string.h> style for C headers.

[aleloi, 2016/08/31 15:16:22]

Seems like that. 21 matches for cstring and 243 for string.h in the code base.
Also, no matches for std::memcmp, but lots of matches for just memcmp.
Done.

 #include <memory>
 #include <utility>
 
 #include "testing/gmock/include/gmock/gmock.h"
 #include "webrtc/modules/audio_mixer/audio_mixer_defines.h"
 #include "webrtc/modules/audio_mixer/audio_mixer.h"
 
 using testing::_;
 using testing::Exactly;
 using testing::Invoke;
@@ skipping 174 matching lines @@
         i < kAudioSources - 1 - AudioMixer::kMaximumAmountOfMixedAudioSources) {
       EXPECT_FALSE(is_mixed) << "Mixing status of AudioSource #" << i
                              << " wrong.";
     } else {
       EXPECT_TRUE(is_mixed) << "Mixing status of AudioSource #" << i
                             << " wrong.";
     }
   }
 }
 
+TEST(AudioMixer, FrameNotModifiedForSingleParticipant) {
+  const std::unique_ptr<AudioMixer> mixer(AudioMixer::Create(kId));
+
+  MockMixerAudioSource participant;
+
+  ResetFrame(participant.fake_frame());
+  const int n_samples = participant.fake_frame()->samples_per_channel_;
+
+  // Modify the frame so that it's not zero.
+  for (int j = 0; j < n_samples; j++) {
+    participant.fake_frame()->data_[j] = j;
+  }
+
+  EXPECT_EQ(0, mixer->SetMixabilityStatus(&participant, true));
+  EXPECT_CALL(participant, GetAudioFrameWithMuted(_, _)).Times(Exactly(2));
+
+  AudioFrame audio_frame;
+  // Two mix iteration to compare after the ramp-up step.
+  for (int i = 0; i < 2; i++) {
+    mixer->Mix(kDefaultSampleRateHz,
+               1,  // number of channels
+               &audio_frame);
+  }
+
+  EXPECT_EQ(std::memcmp(participant.fake_frame()->data_, audio_frame.data_,

[ivoc, 2016/08/31 14:34:24]

Please change the order, i.e. EXPECT_EQ(0, std::memcmp(...));

[aleloi, 2016/08/31 15:16:22]

Done. I also changed in a few other tests.

+                        n_samples),
+            0);
+}
+
+TEST(AudioMixer, FrameNotModifiedForSingleAnonymousParticipant) {

[aleloi, 2016/08/31 11:07:46]

This test compares mixer output in the anonymous case. It fails if the line
|MixAnonomouslyFromList(audio_frame_for_mixing, additionalFramesList);| is
removed.

Previously, there were a few tests that compared audio output with the old
mixer. They didn't use anonymous participants. 

+  const std::unique_ptr<AudioMixer> mixer(AudioMixer::Create(kId));
+
+  MockMixerAudioSource participant;
+
+  ResetFrame(participant.fake_frame());
+  const int n_samples = participant.fake_frame()->samples_per_channel_;
+
+  // Modify the frame so that it's not zero.
+  for (int j = 0; j < n_samples; j++) {
+    participant.fake_frame()->data_[j] = j;
+  }
+
+  EXPECT_EQ(0, mixer->SetMixabilityStatus(&participant, true));
+  EXPECT_EQ(0, mixer->SetAnonymousMixabilityStatus(&participant, true));
+  EXPECT_CALL(participant, GetAudioFrameWithMuted(_, _)).Times(Exactly(2));
+
+  AudioFrame audio_frame;
+  // Two mix iteration to compare after the ramp-up step.
+  for (int i = 0; i < 2; i++) {
+    mixer->Mix(kDefaultSampleRateHz,
+               1,  // number of channels
+               &audio_frame);
+  }
+
+  EXPECT_EQ(std::memcmp(participant.fake_frame()->data_, audio_frame.data_,

[ivoc, 2016/08/31 14:34:24]

Same here.

[aleloi, 2016/08/31 15:16:22]

Done.

+                        n_samples),
+            0);
+}
+
 TEST(AudioMixer, ParticipantSampleRate) {
   const std::unique_ptr<AudioMixer> mixer(AudioMixer::Create(kId));
 
   MockMixerAudioSource participant;
   ResetFrame(participant.fake_frame());
 
   EXPECT_EQ(0, mixer->SetMixabilityStatus(&participant, true));
   for (auto frequency : {8000, 16000, 32000, 48000}) {
     EXPECT_CALL(participant, GetAudioFrameWithMuted(_, frequency))
         .Times(Exactly(1));
@@ skipping 191 matching lines @@
       kAudioSources, MixerAudioSource::AudioFrameInfo::kNormal);
   frame_info[0] = MixerAudioSource::AudioFrameInfo::kMuted;
   std::fill(frames[0].data_, frames[0].data_ + kDefaultSampleRateHz / 100,
             std::numeric_limits<int16_t>::max());
   std::vector<bool> expected_status(kAudioSources, true);
   expected_status[0] = false;
 
   MixAndCompare(frames, frame_info, expected_status);
 }
 }  // namespace webrtc