Fix the wrong output device switching caused by an input device being plugged in.

chromeos/audio/cras_audio_handler.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/audio/cras_audio_handler.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/bind.h"
@@ skipping 499 matching lines @@
     SetupAudioInputState();
     SetActiveInputNode(active_input_node_id_);
   } else {
     if (!ChangeActiveDevice(device, &active_output_node_id_))
       return;
     SetupAudioOutputState();
     SetActiveOutputNode(active_output_node_id_);
   }
 }
 
+bool CrasAudioHandler::HasDeviceChange(const AudioNodeList& new_nodes,
+                                       bool is_input) {
+  size_t num_old_devices = 0;
+  size_t num_new_devices = 0;
+  for (AudioDeviceMap::const_iterator it = audio_devices_.begin();
+       it != audio_devices_.end(); ++it) {
+    if (is_input == it->second.is_input)
+      ++num_old_devices;
+  }
+
+  for (AudioNodeList::const_iterator it = new_nodes.begin();
+       it != new_nodes.end(); ++it) {
+    if (is_input == it->is_input)
+      ++num_new_devices;
+  }
+  return num_old_devices != num_new_devices;
+}
+
 void CrasAudioHandler::UpdateDevicesAndSwitchActive(
     const AudioNodeList& nodes) {
   size_t old_audio_devices_size = audio_devices_.size();
+  bool output_devices_changed = HasDeviceChange(nodes, false);
+  bool input_devices_changed = HasDeviceChange(nodes, true);
   audio_devices_.clear();
   has_alternative_input_ = false;
   has_alternative_output_ = false;
 
   while (!input_devices_pq_.empty())
     input_devices_pq_.pop();
   while (!output_devices_pq_.empty())
     output_devices_pq_.pop();
 
   for (size_t i = 0; i < nodes.size(); ++i) {
@@ skipping 12 matching lines @@
 
     if (device.is_input)
       input_devices_pq_.push(device);
     else
       output_devices_pq_.push(device);
   }
 
   // If audio nodes change is caused by unplugging some non-active audio
   // devices, the previously set active audio device will stay active.
   // Otherwise, switch to a new active audio device according to their priority.
-  if (!NonActiveDeviceUnplugged(old_audio_devices_size,
+  if (input_devices_changed &&
+      !NonActiveDeviceUnplugged(old_audio_devices_size,
                                 audio_devices_.size(),
                                 active_input_node_id_) &&
       !input_devices_pq_.empty())
     SwitchToDevice(input_devices_pq_.top());
-  if (!NonActiveDeviceUnplugged(old_audio_devices_size,
+  if (output_devices_changed &&
+      !NonActiveDeviceUnplugged(old_audio_devices_size,
                                 audio_devices_.size(),
                                 active_output_node_id_) &&
       !output_devices_pq_.empty()) {
     SwitchToDevice(output_devices_pq_.top());
   }
 }
 
 void CrasAudioHandler::HandleGetNodes(const chromeos::AudioNodeList& node_list,
                                       bool success) {
   if (!success) {
     LOG(ERROR) << "Failed to retrieve audio nodes data";
     return;
   }
 
   UpdateDevicesAndSwitchActive(node_list);
   FOR_EACH_OBSERVER(AudioObserver, observers_, OnAudioNodesChanged());
 }
 
 }  // namespace chromeos