properly detect is_default in Device::new() for MacOS

CHANGELOG.md

@@ -1,7 +1,8 @@
 # Unreleased
 
-- ALSA(process_output): pass `silent=true` to `PCM.try_recover`, so it doesn't write to stderr.
+- ALSA(process_output): Pass `silent=true` to `PCM.try_recover`, so it doesn't write to stderr.
 - CoreAudio: `Device::supported_configs` now returns a single element containing the available sample rate range when all elements have the same `mMinimum` and `mMaximum` values (which is the most common case).
+- CoreAudio: Detect default audio device lazily when building a stream, instead of during device enumeration.
 - iOS: Fix example by properly activating audio session.
 - WASAPI: Expose IMMDevice from WASAPI host Device.
 

src/host/coreaudio/macos/enumerate.rs

@@ -81,7 +81,6 @@ impl Iterator for Devices {
     fn next(&mut self) -> Option<Device> {
         self.0.next().map(|id| Device {
             audio_device_id: id,
-            is_default: false,
         })
     }
 }
@@ -109,10 +108,7 @@ pub fn default_input_device() -> Option<Device> {
         return None;
     }
 
-    let device = Device {
-        audio_device_id,
-        is_default: true,
-    };
+    let device = Device { audio_device_id };
     Some(device)
 }
 
@@ -139,10 +135,7 @@ pub fn default_output_device() -> Option<Device> {
         return None;
     }
 
-    let device = Device {
-        audio_device_id,
-        is_default: true,
-    };
+    let device = Device { audio_device_id };
     Some(device)
 }
 

src/host/coreaudio/macos/mod.rs

@@ -159,18 +159,22 @@ impl DeviceTrait for Device {
 #[derive(Clone, PartialEq, Eq)]
 pub struct Device {
     pub(crate) audio_device_id: AudioDeviceID,
-    is_default: bool,
+}
+
+fn is_default_device(device: &Device) -> bool {
+    default_input_device()
+        .map(|d| d.audio_device_id == device.audio_device_id)
+        .unwrap_or(false)
+        || default_output_device()
+            .map(|d| d.audio_device_id == device.audio_device_id)
+            .unwrap_or(false)
 }
 
 impl Device {
     /// Construct a new device given its ID.
     /// Useful for constructing hidden devices.
     pub fn new(audio_device_id: AudioDeviceID) -> Self {
-        Device {
-            audio_device_id,
-            // TODO: This could be made to detect the default device properly.
-            is_default: false,
-        }
+        Self { audio_device_id }
     }
 
     fn name(&self) -> Result<String, DeviceNameError> {
@@ -523,7 +527,7 @@ where
 }
 
 fn audio_unit_from_device(device: &Device, input: bool) -> Result<AudioUnit, coreaudio::Error> {
-    let output_type = if device.is_default && !input {
+    let output_type = if is_default_device(device) && !input {
         coreaudio::audio_unit::IOType::DefaultOutput
     } else {
         coreaudio::audio_unit::IOType::HalOutput
@@ -665,7 +669,7 @@ impl Device {
 
         // If we didn't request the default device, stop the stream if the
         // device disconnects.
-        if !self.is_default {
+        if !is_default_device(self) {
             add_disconnect_listener(&stream, error_callback_disconnect)?;
         }
 
@@ -770,7 +774,7 @@ impl Device {
 
         // If we didn't request the default device, stop the stream if the
         // device disconnects.
-        if !self.is_default {
+        if !is_default_device(self) {
             add_disconnect_listener(&stream, error_callback_disconnect)?;
         }
 

src/samples_formats.rs

@@ -48,13 +48,11 @@ pub enum SampleFormat {
 
     /// `U24` with a valid range of '0..16777216' with `1 << 23 == 8388608` being the origin
     // U24,
-
     /// `u32` with a valid range of `u32::MIN..=u32::MAX` with `1 << 31` being the origin.
     U32,
 
     /// `U48` with a valid range of '0..(1 << 48)' with `1 << 47` being the origin
     // U48,
-
     /// `u64` with a valid range of `u64::MIN..=u64::MAX` with `1 << 63` being the origin.
     U64,