Fix null host

examples/custom.rs

@@ -48,6 +48,10 @@ impl HostTrait for MyHost {
         true
     }
 
+    fn new() -> Result<Self, Error> {
+        Ok(Self)
+    }
+
     fn devices(&self) -> Result<Self::Devices, Error> {
         Ok(std::iter::once(MyDevice))
     }

src/host/aaudio/mod.rs

@@ -158,16 +158,14 @@ struct BufferTuningState {
 pub use crate::iter::{SupportedInputConfigs, SupportedOutputConfigs};
 pub type Devices = std::vec::IntoIter<Device>;
 
-impl Host {
-    pub fn new() -> Result<Self, Error> {
-        Ok(Host)
-    }
-}
-
 impl HostTrait for Host {
     type Devices = Devices;
     type Device = Device;
 
+    fn new() -> Result<Self, Error> {
+        Ok(Host)
+    }
+
     fn is_available() -> bool {
         true
     }

src/host/alsa/mod.rs

@@ -37,18 +37,6 @@ pub struct Host {
 }
 
 impl Host {
-    pub fn new() -> Result<Self, Error> {
-        let inner = AlsaContext::new().map_err(|e| {
-            Error::with_message(
-                ErrorKind::HostUnavailable,
-                format!("ALSA is not available: {e}"),
-            )
-        })?;
-        Ok(Self {
-            inner: Arc::new(inner),
-        })
-    }
-
     // "default" is a virtual ALSA device that redirects to the configured default. We cannot
     // determine its actual capabilities without opening it, so we return Unknown direction.
     fn default_device(&self) -> Device {
@@ -65,6 +53,18 @@ impl HostTrait for Host {
     type Devices = Devices;
     type Device = Device;
 
+    fn new() -> Result<Self, Error> {
+        let inner = AlsaContext::new().map_err(|e| {
+            Error::with_message(
+                ErrorKind::HostUnavailable,
+                format!("ALSA is not available: {e}"),
+            )
+        })?;
+        Ok(Self {
+            inner: Arc::new(inner),
+        })
+    }
+
     fn is_available() -> bool {
         // Assume ALSA is always available on Linux and BSD.
         true

src/host/asio/mod.rs

@@ -36,20 +36,18 @@ pub struct Host {
     asio: Arc<sys::Asio>,
 }
 
-impl Host {
-    pub fn new() -> Result<Self, Error> {
+impl HostTrait for Host {
+    type Devices = Devices;
+    type Device = Device;
+
+    fn new() -> Result<Self, Error> {
         com::com_initialized();
         let asio = GLOBAL_ASIO
             .get_or_init(|| Arc::new(sys::Asio::new()))
             .clone();
         let host = Host { asio };
         Ok(host)
     }
-}
-
-impl HostTrait for Host {
-    type Devices = Devices;
-    type Device = Device;
 
     fn is_available() -> bool {
         true

src/host/audioworklet/mod.rs

@@ -203,8 +203,11 @@ enum Command {
     Pause,
 }
 
-impl Host {
-    pub fn new() -> Result<Self, Error> {
+impl HostTrait for Host {
+    type Devices = Devices;
+    type Device = Device;
+
+    fn new() -> Result<Self, Error> {
         if Self::is_available() {
             Ok(Host)
         } else {
@@ -214,11 +217,6 @@ impl Host {
             ))
         }
     }
-}
-
-impl HostTrait for Host {
-    type Devices = Devices;
-    type Device = Device;
 
     fn is_available() -> bool {
         if let Some(window) = web_sys::window() {

src/host/coreaudio/ios/mod.rs

@@ -54,16 +54,14 @@ impl fmt::Display for Device {
 
 pub struct Host;
 
-impl Host {
-    pub fn new() -> Result<Self, Error> {
-        Ok(Host)
-    }
-}
-
 impl HostTrait for Host {
     type Devices = Devices;
     type Device = Device;
 
+    fn new() -> Result<Self, Error> {
+        Ok(Host)
+    }
+
     fn is_available() -> bool {
         true
     }

src/host/coreaudio/macos/mod.rs

@@ -34,16 +34,14 @@ pub use device::Device;
 #[derive(Debug)]
 pub struct Host;
 
-impl Host {
-    pub fn new() -> Result<Self, Error> {
-        Ok(Host)
-    }
-}
-
 impl HostTrait for Host {
     type Devices = Devices;
     type Device = Device;
 
+    fn new() -> Result<Self, Error> {
+        Ok(Host)
+    }
+
     fn is_available() -> bool {
         // Assume coreaudio is always available
         true

src/host/custom/mod.rs

@@ -28,11 +28,6 @@ use crate::{
 pub struct Host(Box<dyn HostErased>);
 
 impl Host {
-    // this only exists for impl_platform_host, which requires it
-    pub(crate) fn new() -> Result<Self, Error> {
-        Err(Error::new(ErrorKind::HostUnavailable))
-    }
-
     /// Construct a custom host from an arbitrary [`HostTrait`] implementation.
     pub fn from_host<T>(host: T) -> Self
     where
@@ -356,6 +351,10 @@ impl HostTrait for Host {
     type Devices = Devices;
     type Device = Device;
 
+    fn new() -> Result<Self, Error> {
+        Err(Error::new(ErrorKind::HostUnavailable))
+    }
+
     fn is_available() -> bool {
         false
     }

src/host/jack/mod.rs

@@ -44,17 +44,6 @@ pub struct Host {
 }
 
 impl Host {
-    pub fn new() -> Result<Self, Error> {
-        let mut host = Host {
-            name: format!("cpal_client_{}", std::process::id()),
-            connect_ports_automatically: true,
-            start_server_automatically: false,
-            devices_created: vec![],
-        };
-        // Devices don't exist for JACK, they have to be created
-        host.initialize_default_devices();
-        Ok(host)
-    }
     /// Configures whether created ports should automatically connect to system playback/capture
     /// ports.
     ///
@@ -129,6 +118,18 @@ impl HostTrait for Host {
     type Devices = Devices;
     type Device = Device;
 
+    fn new() -> Result<Self, Error> {
+        let mut host = Host {
+            name: format!("cpal_client_{}", std::process::id()),
+            connect_ports_automatically: true,
+            start_server_automatically: false,
+            devices_created: vec![],
+        };
+        // Devices don't exist for JACK, they have to be created
+        host.initialize_default_devices();
+        Ok(host)
+    }
+
     /// JACK is available if
     /// - the jack feature flag is set
     /// - libjack is installed (wouldn't compile without it)

src/host/mod.rs

@@ -86,20 +86,23 @@ pub(crate) mod webaudio;
 #[cfg(feature = "custom")]
 pub(crate) mod custom;
 
-#[cfg(not(any(
-    windows,
-    target_os = "linux",
-    target_os = "dragonfly",
-    target_os = "freebsd",
-    target_os = "netbsd",
-    target_vendor = "apple",
-    target_os = "android",
-    all(
-        target_arch = "wasm32",
-        any(target_os = "emscripten", target_os = "unknown"),
-        feature = "wasm-bindgen"
-    ),
-)))]
+#[cfg(all(
+    not(feature = "custom"),
+    not(any(
+        windows,
+        target_os = "linux",
+        target_os = "dragonfly",
+        target_os = "freebsd",
+        target_os = "netbsd",
+        target_vendor = "apple",
+        target_os = "android",
+        all(
+            target_arch = "wasm32",
+            any(target_os = "emscripten", target_os = "unknown"),
+            feature = "wasm-bindgen"
+        ),
+    )),
+))]
 pub(crate) mod null;
 
 #[cfg(any(

src/host/null/mod.rs

@@ -6,8 +6,10 @@ use std::fmt;
 use std::time::Duration;
 
 use crate::{
-    CallbackInfo, Data, DeviceDescription, DeviceDescriptionBuilder, DeviceId, Error, FrameCount,
-    SampleFormat, StreamConfig, StreamInstant, SupportedStreamConfig, SupportedStreamConfigRange,
+    CallbackInfo, Data, DeviceDescription, DeviceDescriptionBuilder, DeviceId, Error,
+    ErrorKind::DeviceNotAvailable,
+    FrameCount, SampleFormat, StreamConfig, StreamInstant, SupportedStreamConfig,
+    SupportedStreamConfigRange,
     traits::{DeviceTrait, HostTrait, StreamTrait},
 };
 
@@ -33,13 +35,6 @@ pub struct SupportedInputConfigs;
 #[derive(Clone)]
 pub struct SupportedOutputConfigs;
 
-impl Host {
-    #[allow(dead_code)]
-    pub fn new() -> Result<Self, Error> {
-        Ok(Self)
-    }
-}
-
 impl DeviceTrait for Device {
     type SupportedInputConfigs = SupportedInputConfigs;
     type SupportedOutputConfigs = SupportedOutputConfigs;
@@ -54,19 +49,19 @@ impl DeviceTrait for Device {
     }
 
     fn supported_input_configs(&self) -> Result<SupportedInputConfigs, Error> {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 
     fn supported_output_configs(&self) -> Result<SupportedOutputConfigs, Error> {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 
     fn default_input_config(&self) -> Result<SupportedStreamConfig, Error> {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 
     fn default_output_config(&self) -> Result<SupportedStreamConfig, Error> {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 
     fn build_input_stream_raw<D, E>(
@@ -81,7 +76,7 @@ impl DeviceTrait for Device {
         D: FnMut(&Data, &CallbackInfo) + Send + 'static,
         E: FnMut(Error) + Send + 'static,
     {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 
     /// Create an output stream.
@@ -97,14 +92,18 @@ impl DeviceTrait for Device {
         D: FnMut(&mut Data, &CallbackInfo) + Send + 'static,
         E: FnMut(Error) + Send + 'static,
     {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 }
 
 impl HostTrait for Host {
     type Devices = Devices;
     type Device = Device;
 
+    fn new() -> Result<Self, Error> {
+        Ok(Self)
+    }
+
     fn is_available() -> bool {
         false
     }
@@ -124,23 +123,23 @@ impl HostTrait for Host {
 
 impl StreamTrait for Stream {
     fn start(&self) -> Result<(), Error> {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 
     fn pause(&self) -> Result<(), Error> {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 
     fn stop(&self, _timeout: Option<std::time::Duration>) -> Result<(), Error> {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 
     fn now(&self) -> StreamInstant {
-        unimplemented!()
+        StreamInstant::ZERO
     }
 
     fn buffer_size(&self) -> Result<FrameCount, Error> {
-        unimplemented!()
+        Err(Error::with_message(DeviceNotAvailable, "Null host in use"))
     }
 }