This patch will loop through the soundcard and return a list of available devices when the AudioI...

media/audio/mac/audio_manager_mac.cc

 // Copyright (c) 2011 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 <CoreAudio/AudioHardware.h>
 
 #include "base/mac/mac_util.h"
 #include "media/audio/fake_audio_input_stream.h"
 #include "media/audio/fake_audio_output_stream.h"
 #include "media/audio/mac/audio_input_mac.h"
@@ skipping 47 matching lines @@
   OSStatus err = AudioObjectGetPropertyData(kAudioObjectSystemObject,
                                             &property_address,
                                             0,     // inQualifierDataSize
                                             NULL,  // inQualifierData
                                             &output_device_id_size,
                                             &output_device_id);
   return err == kAudioHardwareNoError &&
       output_device_id != kAudioObjectUnknown;
 }
 
+static std::string CFStringToSTLString(const CFStringRef cfstr)

[Chris Rogers, 2011/10/19 01:31:50]

I think it would be a lot better to avoid creating this function and see if you
can use something in "base" like: CFStringToSTLStringWithEncodingT()
in base/sys_string_conversions_mac.mm

[no longer working on chromium, 2011/10/19 17:32:18]

Done.

Thanks for pointing out, it has a API called SysCFStringRefToUTF8 to use.

+{

[scherkus (not reviewing), 2011/10/19 17:38:51]

{ should go on previous line

[no longer working on chromium, 2011/10/19 18:13:21]

The code has been removed.

+  // The method is currently only for kCFStringEncodingUTF8 encoding.
+  CFIndex buf_len = 1 + CFStringGetMaximumSizeForEncoding(
+      CFStringGetLength(cfstr), kCFStringEncodingUTF8);
+  scoped_array<char> buffer(new char[buf_len]);
+  CFStringGetCString(cfstr, buffer.get(), buf_len, kCFStringEncodingUTF8);
+
+  std::string std_string(buffer.get());
+  return std_string;
+}
+
+static void GetAudioDeviceInfo(
+    bool is_input, media::AudioDeviceNames* device_names) {

[scherkus (not reviewing), 2011/10/19 17:38:51]

nit: should go on previous line then align parameters at (

[no longer working on chromium, 2011/10/19 18:13:21]

Done.

+  CFStringRef uid = NULL;
+  CFStringRef name = NULL;
+  int device_number = 0;

[Chris Rogers, 2011/10/19 01:31:50]

"device_count" is probably a better name than "device_number"

[no longer working on chromium, 2011/10/19 17:32:18]

Done.

+  UInt32 size = 0;

[Chris Rogers, 2011/10/19 01:31:50]

Please move variables to closest point of usage.

I know this might seem a little silly, but declaring all variables near the top
of the function is more of an old C-language style and not C++ and chromium
style which is to declare all variables to just before they are actually used.

For example, move the "uid" to around line 139/140
move "device_number" (renamed to "device_count") to line 96 (and initialize to
value on same line)
etc...

[no longer working on chromium, 2011/10/19 17:32:18]

Done.

+
+  device_names->clear();

[Chris Rogers, 2011/10/19 01:31:50]

Just to be careful, probably best to check "device_names" is not NULL and return
early...

[no longer working on chromium, 2011/10/19 17:32:18]

Done.

+
+  // Query the number of total devices.
+  OSStatus result = AudioHardwareGetPropertyInfo(kAudioHardwarePropertyDevices,
+                                                 &size,
+                                                 NULL);
+  if (result)

[Chris Rogers, 2011/10/19 01:31:50]

Can make this simpler:

if (result || !size)

then you don't need to check "device_number" below

[no longer working on chromium, 2011/10/19 17:32:18]

Done.

+    return;
+
+  device_number = size / sizeof(AudioDeviceID);
+  if (!device_number)
+    return;
+
+  // Get the array of device id for each device.
+  scoped_ptr_malloc<AudioDeviceID>
+      devices(reinterpret_cast<AudioDeviceID*>(malloc(size)));

[scherkus (not reviewing), 2011/10/19 17:38:51]

I'm curious -- is malloc required?

[no longer working on chromium, 2011/10/19 18:13:21]

That is how the apple sample code looks like, I think both new and malloc should
work. 

+  AudioDeviceID* device_ids = devices.get();
+  result = AudioHardwareGetProperty(kAudioHardwarePropertyDevices,
+                                    &size,
+                                    device_ids);
+  if (result)
+    return;
+
+  // Iterate each device to gather information.
+  for(int i = 0; i < device_number; ++i) {

[Chris Rogers, 2011/10/19 01:31:50]

nit: space after "for"

[no longer working on chromium, 2011/10/19 17:32:18]

Done.

+    {
+      int channels = 0;
+      // Get the number of input or output channels of the device, exclude
+      // those devices without any right type of channel.
+      AudioDeviceGetPropertyInfo(device_ids[i],
+                                 0,
+                                 is_input,
+                                 kAudioDevicePropertyStreamConfiguration,
+                                 &size,
+                                 NULL);
+      scoped_ptr_malloc<AudioBufferList>
+          buffer(reinterpret_cast<AudioBufferList*>(malloc(size)));
+      AudioBufferList* buffer_list = buffer.get();
+      AudioDeviceGetProperty(device_ids[i],
+                             0,
+                             is_input,
+                             kAudioDevicePropertyStreamConfiguration,
+                             &size,
+                             buffer_list);
+
+      for(uint32 j = 0; j < buffer_list->mNumberBuffers; ++j)

[Chris Rogers, 2011/10/19 01:31:50]

nit: space after "for"

[no longer working on chromium, 2011/10/19 17:32:18]

Done.

+        channels += buffer_list->mBuffers[j].mNumberChannels;
+
+      if (!channels)
+        continue;
+    }
+
+    size = sizeof(uid);

[Chris Rogers, 2011/10/19 01:31:50]

I'd move this line down just below the comment

[no longer working on chromium, 2011/10/19 17:32:18]

Done.

+    // Get device UID.
+    result = AudioDeviceGetProperty(device_ids[i],
+                                    0,
+                                    is_input,
+                                    kAudioDevicePropertyDeviceUID,
+                                    &size,
+                                    &uid);
+    if (result)
+      continue;
+
+    // Get device name.
+    result = AudioDeviceGetProperty(device_ids[i],
+                                    0,
+                                    is_input,
+                                    kAudioObjectPropertyName,
+                                    &size,
+                                    &name);
+    if (result)
+      continue;
+
+    media::AudioDeviceName device_name;
+    device_name.device_name = CFStringToSTLString(name);
+    device_name.unique_id = CFStringToSTLString(uid);
+    device_names->push_back(device_name);
+  }
+}
+
 AudioManagerMac::AudioManagerMac()
     : num_output_streams_(0) {
 }
 
 AudioManagerMac::~AudioManagerMac() {
 }
 
 bool AudioManagerMac::HasAudioOutputDevices() {
   return HasAudioHardware(kAudioHardwarePropertyDefaultOutputDevice);
 }
 
 bool AudioManagerMac::HasAudioInputDevices() {
   return HasAudioHardware(kAudioHardwarePropertyDefaultInputDevice);
 }
 
 void AudioManagerMac::GetAudioInputDeviceNames(
     media::AudioDeviceNames* device_names) {
-  // TODO(xians): query a full list of valid devices.
-  if (HasAudioInputDevices()) {
+  GetAudioDeviceInfo(true, device_names);
+  if (!device_names->empty()) {
     // Add the default device to the list.
     // We use index 0 to make up the unique_id to identify the
     // default devices.
     media::AudioDeviceName name;
     name.device_name = AudioManagerBase::kDefaultDeviceName;
     name.unique_id = "0";
-    device_names->push_back(name);
+    device_names->push_front(name);

[Chris Rogers, 2011/10/19 01:31:50]

Probably worth a comment to describe why you're putting it at the front of the
list.  I assume it's so you have the default device show up first...

I guess it seems kind of obvious from the code itself - but maybe worth
considering a comment too

[no longer working on chromium, 2011/10/19 17:32:18]

Done.

   }
 }
 
 AudioOutputStream* AudioManagerMac::MakeAudioOutputStream(
     const AudioParameters& params) {
   if (!params.IsValid())
     return NULL;
 
   // Limit the number of audio streams opened. This is to prevent using
   // excessive resources for a large number of audio streams. More
@@ skipping 47 matching lines @@
 
 // Called by the stream when it has been released by calling Close().
 void AudioManagerMac::ReleaseInputStream(AudioInputStream* stream) {
   delete stream;
 }
 
 // static
 AudioManager* AudioManager::CreateAudioManager() {
   return new AudioManagerMac();
 }