Adding googAudioNetworkAdaptorConfig to MediaConstraintsInterface.

webrtc/api/localaudiosource.cc

 /*
  *  Copyright 2013 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.
  */
 
@@ skipping 39 matching lines @@
       {MediaConstraintsInterface::kIntelligibilityEnhancer,
        options->intelligibility_enhancer},
       {MediaConstraintsInterface::kLevelControl, options->level_control},
       {MediaConstraintsInterface::kHighpassFilter, options->highpass_filter},
       {MediaConstraintsInterface::kTypingNoiseDetection,
        options->typing_detection},
       {MediaConstraintsInterface::kAudioMirroring, options->stereo_swapping}
   };
 
   for (const auto& constraint : constraints) {
+    // Set non-boolean constraints.
+    if (0 == constraint.key.compare(
+            MediaConstraintsInterface::kLevelControlInitialPeakLevelDBFS)) {
+      float level_control_initial_peak_level_dbfs;

[the sun, 2016/11/09 10:14:25]

= 0.0f;

*always* initialize. Code may be changed and lines moved around. It is very easy
to forget a thing like this and end up in an unexpected state.

+      if (rtc::FromString(constraint.value,
+                          &level_control_initial_peak_level_dbfs)) {
+        options->level_control_initial_peak_level_dbfs =
+            rtc::Optional<float>(level_control_initial_peak_level_dbfs);
+      }
+      continue;
+    }
+    if (constraint.key.compare(
+            MediaConstraintsInterface::kAudioNetworkAdaptorConfig) == 0) {
+      // When |kAudioNetworkAdaptorConfig| is defined, it both means that audio
+      // network adaptor is wanted, and provides the config string.
+      options->audio_network_adaptor = rtc::Optional<bool>(true);
+      options->audio_network_adaptor_config =
+          rtc::Optional<std::string>(constraint.value);

[the sun, 2016/11/09 10:14:25]

Is there any way we can validate the string at this stage?

[minyue-webrtc, 2016/12/02 10:34:19]

The interpretation and validity check of the string are in the audio network
adaptor. We may need to instantiate it to see if the string is valid. Therefore,
we may better just pass it down at this stage.

+      continue;
+    }
+
+    // Parse boolean value.
     bool value = false;
     if (!rtc::FromString(constraint.value, &value))
       continue;
 
     for (auto& entry : key_to_value) {
       if (constraint.key.compare(entry.name) == 0)
         entry.value = rtc::Optional<bool>(value);
     }
   }
-
-  // Set non-boolean constraints.

[minyue-webrtc, 2016/11/01 10:55:09]

This is a refactoring. This part is moved into the loop since FindFirst makes
another loop, which can be omitted.

-  std::string value;
-  if (constraints.FindFirst(
-          MediaConstraintsInterface::kLevelControlInitialPeakLevelDBFS,
-          &value)) {
-    float level_control_initial_peak_level_dbfs;
-    if (rtc::FromString(value, &level_control_initial_peak_level_dbfs)) {
-      options->level_control_initial_peak_level_dbfs =
-          rtc::Optional<float>(level_control_initial_peak_level_dbfs);
-    }
-  }
 }
 
 }  // namespace
 
 rtc::scoped_refptr<LocalAudioSource> LocalAudioSource::Create(
     const PeerConnectionFactoryInterface::Options& options,
     const MediaConstraintsInterface* constraints) {
   rtc::scoped_refptr<LocalAudioSource> source(
       new rtc::RefCountedObject<LocalAudioSource>());
   source->Initialize(options, constraints);
@@ skipping 27 matching lines @@
 void LocalAudioSource::Initialize(
     const PeerConnectionFactoryInterface::Options& options,
     const cricket::AudioOptions* audio_options) {
   if (!audio_options)
     return;
 
   options_ = *audio_options;
 }
 
 }  // namespace webrtc