Output device enumeration for Alsa, plus unit test.

TBR=vrk@chromium.org
BUG=276894

Review URL: https://chromiumcodereview.appspot.com/23480030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221704 0039d316-1c4b-4281-b951-d872f2087c98

media/audio/audio_manager_base.cc

@@ -317,7 +317,7 @@ void AudioManagerBase::GetAudioInputDeviceNames(
 void AudioManagerBase::GetAudioOutputDeviceNames(
     AudioDeviceNames* device_names) {
   // TODO(joi): Remove this and keep pure virtual once implemented everywhere.
-  NOTIMPLEMENTED();
+  NOTREACHED() << "Don't use this yet, it's not ready on all platforms!";
 }
 
 void AudioManagerBase::ReleaseOutputStream(AudioOutputStream* stream) {

media/audio/audio_manager_unittest.cc

@@ -7,21 +7,19 @@
 #include "media/audio/audio_manager.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_LINUX)
+#include "media/audio/linux/audio_manager_linux.h"
+#endif  // defined(OS_LINUX)
+
 #if defined(USE_PULSEAUDIO)
 #include "media/audio/pulse/audio_manager_pulse.h"
-#endif
+#endif  // defined(USE_PULSEAUDIO)
 
 namespace media {
 
-// TODO(joi): Remove guards once implemented for all platforms.
-TEST(AudioManagerTest, GetAudioOutputDeviceNames) {
-#if defined(USE_PULSEAUDIO)
-  scoped_ptr<AudioManager> audio_manager_pulse(AudioManagerPulse::Create());
-  if (!audio_manager_pulse)
-    return;
-
+void GetAudioOutputDeviceNamesImpl(AudioManager* audio_manager) {
   AudioDeviceNames device_names;
-  audio_manager_pulse->GetAudioOutputDeviceNames(&device_names);
+  audio_manager->GetAudioOutputDeviceNames(&device_names);
 
   VLOG(2) << "Got " << device_names.size() << " audio output devices.";
   for (AudioDeviceNames::iterator it = device_names.begin();
@@ -31,7 +29,26 @@ TEST(AudioManagerTest, GetAudioOutputDeviceNames) {
     EXPECT_FALSE(it->device_name.empty());
     VLOG(2) << "Device ID(" << it->unique_id << "), label: " << it->device_name;
   }
+}
+
+TEST(AudioManagerTest, GetAudioOutputDeviceNames) {
+#if defined(USE_PULSEAUDIO)
+  {
+    VLOG(2) << "Testing AudioManagerPulse.";
+    scoped_ptr<AudioManager> pulse_audio_manager(AudioManagerPulse::Create());
+    if (pulse_audio_manager.get())
+      GetAudioOutputDeviceNamesImpl(pulse_audio_manager.get());
+    else
+      LOG(WARNING) << "No pulseaudio on this system.";
+  }
 #endif  // defined(USE_PULSEAUDIO)
+#if defined(USE_ALSA)
+  {
+    VLOG(2) << "Testing AudioManagerLinux.";
+    scoped_ptr<AudioManager> alsa_audio_manager(new AudioManagerLinux());
+    GetAudioOutputDeviceNamesImpl(alsa_audio_manager.get());
+  }
+#endif  // defined(USE_ALSA)
 }
 
 }  // namespace media

media/audio/linux/audio_manager_linux.cc

@@ -42,9 +42,9 @@ static const int kDefaultSampleRate = 48000;
 // hence surround devices are not stored in the list.
 static const char* kInvalidAudioInputDevices[] = {
   "default",
+  "dmix",
   "null",
   "pulse",
-  "dmix",
   "surround",
 };
 
@@ -105,7 +105,13 @@ void AudioManagerLinux::ShowAudioInputSettings() {
 void AudioManagerLinux::GetAudioInputDeviceNames(
     media::AudioDeviceNames* device_names) {
   DCHECK(device_names->empty());
-  GetAlsaAudioInputDevices(device_names);
+  GetAlsaAudioDevices(kStreamCapture, device_names);
+}
+
+void AudioManagerLinux::GetAudioOutputDeviceNames(
+    media::AudioDeviceNames* device_names) {
+  DCHECK(device_names->empty());
+  GetAlsaAudioDevices(kStreamPlayback, device_names);
 }
 
 AudioParameters AudioManagerLinux::GetInputStreamParameters(
@@ -117,7 +123,8 @@ AudioParameters AudioManagerLinux::GetInputStreamParameters(
       kDefaultSampleRate, 16, kDefaultInputBufferSize);
 }
 
-void AudioManagerLinux::GetAlsaAudioInputDevices(
+void AudioManagerLinux::GetAlsaAudioDevices(
+    StreamType type,
     media::AudioDeviceNames* device_names) {
   // Constants specified by the ALSA API for device hints.
   static const char kPcmInterfaceName[] = "pcm";
@@ -128,37 +135,40 @@ void AudioManagerLinux::GetAlsaAudioInputDevices(
     void** hints = NULL;
     int error = wrapper_->DeviceNameHint(card, kPcmInterfaceName, &hints);
     if (!error) {
-      GetAlsaDevicesInfo(hints, device_names);
+      GetAlsaDevicesInfo(type, hints, device_names);
 
       // Destroy the hints now that we're done with it.
       wrapper_->DeviceNameFreeHint(hints);
     } else {
-      DLOG(WARNING) << "GetAudioInputDevices: unable to get device hints: "
+      DLOG(WARNING) << "GetAlsaAudioDevices: unable to get device hints: "
                     << wrapper_->StrError(error);
     }
   }
 }
 
 void AudioManagerLinux::GetAlsaDevicesInfo(
-    void** hints, media::AudioDeviceNames* device_names) {
+    AudioManagerLinux::StreamType type,
+    void** hints,
+    media::AudioDeviceNames* device_names) {
   static const char kIoHintName[] = "IOID";
   static const char kNameHintName[] = "NAME";
   static const char kDescriptionHintName[] = "DESC";
-  static const char kOutputDevice[] = "Output";
+
+  const char* unwanted_device_type = UnwantedDeviceTypeWhenEnumerating(type);
 
   for (void** hint_iter = hints; *hint_iter != NULL; hint_iter++) {
-    // Only examine devices that are input capable.  Valid values are
+    // Only examine devices of the right type.  Valid values are
     // "Input", "Output", and NULL which means both input and output.
     scoped_ptr_malloc<char> io(wrapper_->DeviceNameGetHint(*hint_iter,
                                                            kIoHintName));
-    if (io != NULL && strcmp(kOutputDevice, io.get()) == 0)
+    if (io != NULL && strcmp(unwanted_device_type, io.get()) == 0)
       continue;
 
-    // Found an input device, prepend the default device since we always want
-    // it to be on the top of the list for all platforms. And there is no
-    // duplicate counting here since it is only done if the list is still empty.
-    // Note, pulse has exclusively opened the default device, so we must open
-    // the device via the "default" moniker.
+    // Found a device, prepend the default device since we always want
+    // it to be on the top of the list for all platforms. And there is
+    // no duplicate counting here since it is only done if the list is
+    // still empty.  Note, pulse has exclusively opened the default
+    // device, so we must open the device via the "default" moniker.
     if (device_names->empty()) {
       device_names->push_front(media::AudioDeviceName(
           AudioManagerBase::kDefaultDeviceName,
@@ -170,7 +180,7 @@ void AudioManagerLinux::GetAlsaDevicesInfo(
         wrapper_->DeviceNameGetHint(*hint_iter, kNameHintName));
 
     // Find out if the device is available.
-    if (IsAlsaDeviceAvailable(unique_device_name.get())) {
+    if (IsAlsaDeviceAvailable(type, unique_device_name.get())) {
       // Get the description for the device.
       scoped_ptr_malloc<char> desc(wrapper_->DeviceNameGetHint(
           *hint_iter, kDescriptionHintName));
@@ -196,25 +206,46 @@ void AudioManagerLinux::GetAlsaDevicesInfo(
   }
 }
 
-bool AudioManagerLinux::IsAlsaDeviceAvailable(const char* device_name) {
+// static
+bool AudioManagerLinux::IsAlsaDeviceAvailable(
+    AudioManagerLinux::StreamType type,
+    const char* device_name) {
   if (!device_name)
     return false;
 
-  // Check if the device is in the list of invalid devices.
-  for (size_t i = 0; i < arraysize(kInvalidAudioInputDevices); ++i) {
-    if (strncmp(kInvalidAudioInputDevices[i], device_name,
-                strlen(kInvalidAudioInputDevices[i])) == 0)
-      return false;
+  // We do prefix matches on the device name to see whether to include
+  // it or not.
+  if (type == kStreamCapture) {
+    // Check if the device is in the list of invalid devices.
+    for (size_t i = 0; i < arraysize(kInvalidAudioInputDevices); ++i) {
+      if (strncmp(kInvalidAudioInputDevices[i], device_name,
+                  strlen(kInvalidAudioInputDevices[i])) == 0)
+        return false;
+    }
+    return true;
+  } else {
+    DCHECK_EQ(kStreamPlayback, type);
+    // We prefer the device type that maps straight to hardware but
+    // goes through software conversion if needed (e.g. incompatible
+    // sample rate).
+    // TODO(joi): Should we prefer "hw" instead?
+    static const char kDeviceTypeDesired[] = "plughw";
+    return strncmp(kDeviceTypeDesired,
+                   device_name,
+                   arraysize(kDeviceTypeDesired) - 1) == 0;
   }
+}
 
-  return true;
+// static
+const char* AudioManagerLinux::UnwantedDeviceTypeWhenEnumerating(
+    AudioManagerLinux::StreamType wanted_type) {
+  return wanted_type == kStreamPlayback ? "Input" : "Output";
 }
 
-bool AudioManagerLinux::HasAnyAlsaAudioDevice(StreamType stream) {
+bool AudioManagerLinux::HasAnyAlsaAudioDevice(
+    AudioManagerLinux::StreamType stream) {
   static const char kPcmInterfaceName[] = "pcm";
   static const char kIoHintName[] = "IOID";
-  const char* kNotWantedDevice =
-      (stream == kStreamPlayback ? "Input" : "Output");
   void** hints = NULL;
   bool has_device = false;
   int card = -1;
@@ -230,7 +261,8 @@ bool AudioManagerLinux::HasAnyAlsaAudioDevice(StreamType stream) {
         // "Input", "Output", and NULL which means both input and output.
         scoped_ptr_malloc<char> io(wrapper_->DeviceNameGetHint(*hint_iter,
                                                                kIoHintName));
-        if (io != NULL && strcmp(kNotWantedDevice, io.get()) == 0)
+        const char* unwanted_type = UnwantedDeviceTypeWhenEnumerating(stream);
+        if (io != NULL && strcmp(unwanted_type, io.get()) == 0)
           continue;  // Wrong type, skip the device.
 
         // Found an input device.

media/audio/linux/audio_manager_linux.h

@@ -27,6 +27,8 @@ class MEDIA_EXPORT AudioManagerLinux : public AudioManagerBase {
   virtual void ShowAudioInputSettings() OVERRIDE;
   virtual void GetAudioInputDeviceNames(media::AudioDeviceNames* device_names)
       OVERRIDE;
+  virtual void GetAudioOutputDeviceNames(media::AudioDeviceNames* device_names)
+      OVERRIDE;
   virtual AudioParameters GetInputStreamParameters(
       const std::string& device_id) OVERRIDE;
 
@@ -55,14 +57,22 @@ class MEDIA_EXPORT AudioManagerLinux : public AudioManagerBase {
     kStreamCapture,
   };
 
-  // Gets a list of available ALSA input devices.
-  void GetAlsaAudioInputDevices(media::AudioDeviceNames* device_names);
+  // Gets a list of available ALSA devices.
+  void GetAlsaAudioDevices(StreamType type,
+                           media::AudioDeviceNames* device_names);
 
-  // Gets the ALSA devices' names and ids.
-  void GetAlsaDevicesInfo(void** hint, media::AudioDeviceNames* device_names);
+  // Gets the ALSA devices' names and ids that support streams of the
+  // given type.
+  void GetAlsaDevicesInfo(StreamType type,
+                          void** hint,
+                          media::AudioDeviceNames* device_names);
 
   // Checks if the specific ALSA device is available.
-  bool IsAlsaDeviceAvailable(const char* device_name);
+  static bool IsAlsaDeviceAvailable(StreamType type,
+                                    const char* device_name);
+
+  static const char* UnwantedDeviceTypeWhenEnumerating(
+      StreamType wanted_type);
 
   // Returns true if a device is present for the given stream type.
   bool HasAnyAlsaAudioDevice(StreamType stream);

media/media.gyp

@@ -1042,6 +1042,11 @@
             'base/media_file_checker_unittest.cc',
           ],
         }],
+        ['use_alsa==1', {
+          'defines': [
+            'USE_ALSA',
+          ],
+        }],
         ['use_pulseaudio==1', {
           'defines': [
             'USE_PULSEAUDIO',