Listen for OutputNodeVolumeChanged signal

chromeos/dbus/cras_audio_client.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chromeos/dbus/cras_audio_client.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/format_macros.h"
@@ skipping 227 matching lines @@
                    weak_ptr_factory_.GetWeakPtr()));
 
     // Monitor the D-Bus signal for active input node change.
     cras_proxy_->ConnectToSignal(
         cras::kCrasControlInterface,
         cras::kActiveInputNodeChanged,
         base::Bind(&CrasAudioClientImpl::ActiveInputNodeChangedReceived,
                    weak_ptr_factory_.GetWeakPtr()),
         base::Bind(&CrasAudioClientImpl::SignalConnected,
                    weak_ptr_factory_.GetWeakPtr()));
+
+    //
+    cras_proxy_->ConnectToSignal(
+        cras::kCrasControlInterface, "OutputNodeVolumeChanged",
+        base::Bind(&CrasAudioClientImpl::OutputNodeVolumeChangedReceived,
+                   weak_ptr_factory_.GetWeakPtr()),
+        base::Bind(&CrasAudioClientImpl::SignalConnected,
+                   weak_ptr_factory_.GetWeakPtr()));
   }
 
  private:
   // Called when the cras signal is initially connected.
   void SignalConnected(const std::string& interface_name,
                        const std::string& signal_name,
                        bool success) {
     LOG_IF(ERROR, !success)
         << "Failed to connect to cras signal:" << signal_name;
   }
@@ skipping 44 matching lines @@
   void ActiveInputNodeChangedReceived(dbus::Signal* signal) {
     dbus::MessageReader reader(signal);
     uint64_t node_id;
     if (!reader.PopUint64(&node_id)) {
       LOG(ERROR) << "Error reading signal from cras:"
                  << signal->ToString();
     }
     FOR_EACH_OBSERVER(Observer, observers_, ActiveInputNodeChanged(node_id));
   }
 
+  void OutputNodeVolumeChangedReceived(dbus::Signal* signal) {
+    dbus::MessageReader reader(signal);
+    uint64_t node_id;
+    int volume;
+
+    if (!reader.PopUint64(&node_id)) {
+      LOG(ERROR) << "Error eading signal from cras:" << signal->ToString();
+    }
+    if (!reader.PopInt32(&volume)) {
+      LOG(ERROR) << "Error eading signal from cras:" << signal->ToString();
+    }
+    FOR_EACH_OBSERVER(Observer, observers_,
+                      OutputNodeVolumeChanged(node_id, volume));
+  }
+
   void OnGetVolumeState(const GetVolumeStateCallback& callback,
                         dbus::Response* response) {
     bool success = true;
     VolumeState volume_state;
     if (response) {
       dbus::MessageReader reader(response);
       if (!reader.PopInt32(&volume_state.output_volume) ||
           !reader.PopBool(&volume_state.output_system_mute) ||
           !reader.PopInt32(&volume_state.input_gain) ||
           !reader.PopBool(&volume_state.input_mute) ||
@@ skipping 140 matching lines @@
 
 CrasAudioClient::~CrasAudioClient() {
 }
 
 // static
 CrasAudioClient* CrasAudioClient::Create() {
   return new CrasAudioClientImpl();
 }
 
 }  // namespace chromeos