Merge pull request #350 from jiminycrick/fix-stream-panic

Better error handling for stream creation

src/lib.rs

@@ -97,8 +97,8 @@
 //!
 #![cfg_attr(test, deny(missing_docs))]
 pub use cpal::{
-    traits::DeviceTrait, Device, Devices, DevicesError, InputDevices, OutputDevices,
-    SupportedStreamConfig, self,
+    self, traits::DeviceTrait, Device, Devices, DevicesError, InputDevices, OutputDevices,
+    SupportedStreamConfig,
 };
 
 mod conversions;

src/stream.rs

@@ -105,9 +105,30 @@ impl error::Error for PlayError {
 #[derive(Debug)]
 pub enum StreamError {
     PlayStreamError(cpal::PlayStreamError),
+    DefaultStreamConfigError(cpal::DefaultStreamConfigError),
+    BuildStreamError(cpal::BuildStreamError),
+    SupportedStreamConfigsError(cpal::SupportedStreamConfigsError),
     NoDevice,
 }
 
+impl From<cpal::DefaultStreamConfigError> for StreamError {
+    fn from(err: cpal::DefaultStreamConfigError) -> Self {
+        Self::DefaultStreamConfigError(err)
+    }
+}
+
+impl From<cpal::SupportedStreamConfigsError> for StreamError {
+    fn from(err: cpal::SupportedStreamConfigsError) -> Self {
+        Self::SupportedStreamConfigsError(err)
+    }
+}
+
+impl From<cpal::BuildStreamError> for StreamError {
+    fn from(err: cpal::BuildStreamError) -> Self {
+        Self::BuildStreamError(err)
+    }
+}
+
 impl From<cpal::PlayStreamError> for StreamError {
     fn from(err: cpal::PlayStreamError) -> Self {
         Self::PlayStreamError(err)
@@ -118,6 +139,9 @@ impl fmt::Display for StreamError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             Self::PlayStreamError(e) => e.fmt(f),
+            Self::BuildStreamError(e) => e.fmt(f),
+            Self::DefaultStreamConfigError(e) => e.fmt(f),
+            Self::SupportedStreamConfigsError(e) => e.fmt(f),
             Self::NoDevice => write!(f, "NoDevice"),
         }
     }
@@ -127,6 +151,9 @@ impl error::Error for StreamError {
     fn source(&self) -> Option<&(dyn error::Error + 'static)> {
         match self {
             Self::PlayStreamError(e) => Some(e),
+            Self::BuildStreamError(e) => Some(e),
+            Self::DefaultStreamConfigError(e) => Some(e),
+            Self::SupportedStreamConfigsError(e) => Some(e),
             Self::NoDevice => None,
         }
     }
@@ -142,7 +169,6 @@ pub(crate) trait CpalDeviceExt {
     fn try_new_output_stream(
         &self,
     ) -> Result<(Arc<DynamicMixerController<f32>>, cpal::Stream), StreamError>;
-    fn new_output_stream(&self) -> (Arc<DynamicMixerController<f32>>, cpal::Stream);
 }
 
 impl CpalDeviceExt for cpal::Device {
@@ -192,37 +218,16 @@ impl CpalDeviceExt for cpal::Device {
         &self,
     ) -> Result<(Arc<DynamicMixerController<f32>>, cpal::Stream), StreamError> {
         // Determine the format to use for the new stream.
-        let default_format = match self.default_output_config() {
-            Ok(f) => f,
-            Err(_) => return Err(StreamError::NoDevice),
-        };
-
-        Ok(self
-            .new_output_stream_with_format(default_format)
-            .unwrap_or_else(|err| {
-                // look through all supported formats to see if another works
-                supported_output_formats(self)
-                    .filter_map(|format| self.new_output_stream_with_format(format).ok())
-                    .next()
-                    .ok_or(err)
-                    .expect("build_output_stream failed with all supported formats")
-            }))
-    }
-
-    fn new_output_stream(&self) -> (Arc<DynamicMixerController<f32>>, cpal::Stream) {
-        // Determine the format to use for the new stream.
-        let default_format = self
-            .default_output_config()
-            .expect("The device doesn't support any format!?");
+        let default_format = self.default_output_config()?;
 
         self.new_output_stream_with_format(default_format)
-            .unwrap_or_else(|err| {
+            .or_else(|err| {
                 // look through all supported formats to see if another works
-                supported_output_formats(self)
-                    .filter_map(|format| self.new_output_stream_with_format(format).ok())
-                    .next()
-                    .ok_or(err)
-                    .expect("build_output_stream failed with all supported formats")
+                supported_output_formats(self)?
+                .filter_map(|format| self.new_output_stream_with_format(format).ok())
+                .next()
+                // return original error if nothing works
+                .ok_or(StreamError::BuildStreamError(err))
             })
     }
 }
@@ -230,16 +235,13 @@ impl CpalDeviceExt for cpal::Device {
 /// All the supported output formats with sample rates
 fn supported_output_formats(
     device: &cpal::Device,
-) -> impl Iterator<Item = cpal::SupportedStreamConfig> {
+) -> Result<impl Iterator<Item = cpal::SupportedStreamConfig>, StreamError> {
     const HZ_44100: cpal::SampleRate = cpal::SampleRate(44_100);
 
-    let mut supported: Vec<_> = device
-        .supported_output_configs()
-        .expect("No supported output formats")
-        .collect();
+    let mut supported: Vec<_> = device.supported_output_configs()?.collect();
     supported.sort_by(|a, b| b.cmp_default_heuristics(a));
 
-    supported.into_iter().flat_map(|sf| {
+    Ok(supported.into_iter().flat_map(|sf| {
         let max_rate = sf.max_sample_rate();
         let min_rate = sf.min_sample_rate();
         let mut formats = vec![sf.clone().with_max_sample_rate()];
@@ -248,5 +250,5 @@ fn supported_output_formats(
         }
         formats.push(sf.with_sample_rate(min_rate));
         formats
-    })
+    }))
 }