ASIO: Extension trait + open control panel

Author: Sin-tel

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `DeviceBusy` error variant for retriable device access errors (EBUSY, EAGAIN).
 - **ALSA**: `Debug` implementations for `Host`, `Device`, `Stream`, and internal types.
 - **ALSA**: Example demonstrating ALSA error suppression during enumeration.
+- **ASIO**: Extension trait for ASIO devices, which allows opening the control panel.
 - **WASAPI**: Allow non-native sample rates to be used via as-necessary resampling in the WASAPI server process.
 
 ### Changed

asio-sys/build.rs

@@ -72,6 +72,7 @@ fn main() {
     // Print out links to needed libraries
     println!("cargo:rustc-link-lib=dylib=ole32");
     println!("cargo:rustc-link-lib=dylib=user32");
+    println!("cargo:rustc-link-lib=dylib=Advapi32");
     println!("cargo:rustc-link-search={}", out_dir.display());
     println!("cargo:rustc-link-lib=static=asio");
     println!("cargo:rustc-cfg=asio");
@@ -237,6 +238,7 @@ fn create_bindings(cpal_asio_dir: &PathBuf) {
         .allowlist_function("ASIOStart")
         .allowlist_function("ASIOStop")
         .allowlist_function("ASIODisposeBuffers")
+        .allowlist_function("ASIOControlPanel")
         .allowlist_function("ASIOExit")
         .allowlist_function("load_asio_driver")
         .allowlist_function("remove_current_driver")

asio-sys/src/bindings/mod.rs

@@ -788,6 +788,11 @@ impl Driver {
         let mut mcb = MESSAGE_CALLBACKS.lock().unwrap();
         mcb.retain(|&(id, _)| id != rem_id);
     }
+
+    /// Opens the ASIO driver's control panel window.
+    pub fn open_control_panel(&self) -> Result<(), AsioError> {
+        unsafe { asio_result!(ai::ASIOControlPanel()) }
+    }
 }
 
 impl DriverState {

src/platform/asio.rs

@@ -0,0 +1,67 @@
+//! Implementations for ASIO-specific device functionality.
+
+use crate::BackendSpecificError;
+use crate::Device;
+
+/// Extension trait for ASIO-specific device functionality.
+pub trait AsioDeviceExt {
+    /// Returns `true` if this device is an ASIO device.
+    fn is_asio_device(&self) -> bool;
+
+    /// Opens the ASIO driver's control panel window.
+    ///
+    /// This provides access to device-specific settings like buffer size,
+    /// sample rate, input/output routing, and hardware-specific features.
+    ///
+    /// # Blocking Behavior
+    ///
+    /// **WARNING**: This call may block until the user closes the control panel.
+    /// Consider spawning a thread to avoid blocking the main thread.
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if this device is not an ASIO device.
+    fn asio_open_control_panel(&self) -> Result<(), BackendSpecificError>;
+}
+
+#[cfg(all(target_os = "windows", feature = "asio"))]
+impl AsioDeviceExt for Device {
+    fn is_asio_device(&self) -> bool {
+        matches!(self.as_inner(), crate::platform::DeviceInner::Asio(_))
+    }
+
+    fn asio_open_control_panel(&self) -> Result<(), BackendSpecificError> {
+        use crate::platform::DeviceInner;
+
+        if let DeviceInner::Asio(ref asio_device) = self.as_inner() {
+            asio_device
+                .driver
+                .open_control_panel()
+                .map_err(|e| BackendSpecificError {
+                    description: format!("Failed to open control panel: {:?}", e),
+                })
+        } else {
+            Err(BackendSpecificError {
+                description: "Not an ASIO device".to_string(),
+            })
+        }
+    }
+}
+
+#[cfg(not(all(target_os = "windows", feature = "asio")))]
+impl AsioDeviceExt for Device {
+    fn is_asio_device(&self) -> bool {
+        false
+    }
+
+    fn asio_open_control_panel(&self) -> Result<(), BackendSpecificError> {
+        Err(not_available())
+    }
+}
+
+#[cfg(not(all(target_os = "windows", feature = "asio")))]
+fn not_available() -> BackendSpecificError {
+    BackendSpecificError {
+        description: "ASIO is not available on this platform".to_string(),
+    }
+}

src/platform/mod.rs

@@ -10,6 +10,8 @@ pub use self::platform_impl::*;
 #[cfg(feature = "custom")]
 pub use crate::host::custom::{Device as CustomDevice, Host as CustomHost, Stream as CustomStream};
 
+pub mod asio;
+
 /// A macro to assist with implementing a platform's dynamically dispatched [`Host`] type.
 ///
 /// These dynamically dispatched types are necessary to allow for users to switch between hosts at