Add support for OpenBSD platform via sndio host

.github/workflows/cpal.yml

@@ -83,6 +83,17 @@ jobs:
       run: sudo apt-get install libasound2-dev
     - name: Install libjack
       run: sudo apt-get install libjack-jackd2-dev libjack-jackd2-0
+    - name: Install sndio
+      run: |
+        sudo apt-get install build-essential &&
+        git clone https://caoua.org/git/sndio &&
+        cd sndio &&
+        ./configure &&
+        make &&
+        sudo mkdir /var/run/sndiod &&
+        sudo useradd -r -g audio -s /sbin/nologin -d /var/run/sndiod sndiod &&
+        sudo make install &&
+        sudo ldconfig 
     - name: Install stable
       uses: actions-rs/toolchain@v1
       with:
@@ -99,6 +110,11 @@ jobs:
       with:
         command: test
         args: --all --all-features --verbose
+    - name: Run with jack feature
+      uses: actions-rs/cargo@v1
+      with:
+        command: test
+        args: --all --features jack --verbose
 
   linux-check-and-test-armv7:
     runs-on: ubuntu-latest

.gitignore

@@ -4,3 +4,4 @@
 .DS_Store
 recorded.wav
 rls*.log
+rusty-tags.*

Cargo.toml

@@ -10,6 +10,7 @@ keywords = ["audio", "sound"]
 
 [features]
 asio = ["asio-sys", "num-traits"] # Only available on Windows. See README for setup instructions.
+linux-sndio = ["sndio-sys", "libc"]  # sndio on Linux (normally this is only used on OpenBSD)
 
 [dependencies]
 thiserror = "1.0.2"
@@ -34,6 +35,14 @@ libc = "0.2.65"
 parking_lot = "0.11"
 jack = { version = "0.7.0", optional = true }
 
+[target.'cfg(target_os = "linux")'.dependencies]
+sndio-sys = { version = "0.0.*", optional = true }
+libc = { version = "0.2.65", optional = true }
+
+[target.'cfg(target_os = "openbsd")'.dependencies]
+sndio-sys = "0.0.*"
+libc = "0.2.65"
+
 [target.'cfg(any(target_os = "macos", target_os = "ios"))'.dependencies]
 core-foundation-sys = "0.8.2" # For linking to CoreFoundation.framework and handling device name `CFString`s.
 mach = "0.3" # For access to mach_timebase type.

README.md

@@ -21,6 +21,7 @@ Currently, supported hosts include:
 - macOS (via CoreAudio)
 - iOS (via CoreAudio)
 - Android (via Oboe)
+- OpenBSD (via sndio)
 - Emscripten
 
 Note that on Linux, the ALSA development files are required. These are provided

src/error.rs

@@ -147,7 +147,7 @@ pub enum PauseStreamError {
 }
 
 /// Errors that might occur while a stream is running.
-#[derive(Debug, Error)]
+#[derive(Debug, Error, Clone)]
 pub enum StreamError {
     /// The device no longer exists. This can happen if the device is disconnected while the
     /// program is running.

src/host/mod.rs

@@ -14,6 +14,11 @@ pub(crate) mod jack;
 pub(crate) mod null;
 #[cfg(target_os = "android")]
 pub(crate) mod oboe;
+#[cfg(any(
+    target_os = "openbsd",
+    all(target_os = "linux", feature = "linux-sndio")
+))]
+pub(crate) mod sndio;
 #[cfg(windows)]
 pub(crate) mod wasapi;
 #[cfg(all(target_arch = "wasm32", feature = "wasm-bindgen"))]

src/host/sndio/adapters.rs

@@ -0,0 +1,70 @@
+use crate::{Data, FrameCount, InputCallbackInfo, OutputCallbackInfo, Sample};
+use samples_formats::TypeSampleFormat;
+
+/// When given an input data callback that expects samples in the specified sample format, return
+/// an input data callback that expects samples in the I16 sample format. The `buffer_size` is in
+/// samples.
+pub(super) fn input_adapter_callback<T, D>(
+    mut original_data_callback: D,
+    buffer_size: FrameCount,
+) -> Box<dyn FnMut(&Data, &InputCallbackInfo) + Send + 'static>
+where
+    D: FnMut(&Data, &InputCallbackInfo) + Send + 'static,
+    T: Sample + TypeSampleFormat + Copy + Send + Default + 'static,
+{
+    let mut adapted_buf = vec![T::default(); buffer_size as usize];
+
+    Box::new(move |data: &Data, info: &InputCallbackInfo| {
+        let data_slice: &[i16] = data.as_slice().unwrap(); // unwrap OK because data is always i16
+        let adapted_slice = &mut adapted_buf;
+        assert_eq!(data_slice.len(), adapted_slice.len());
+        for (adapted_ref, data_element) in adapted_slice.iter_mut().zip(data_slice.iter()) {
+            *adapted_ref = T::from(data_element);
+        }
+
+        // Note: we construct adapted_data here instead of in the parent function because adapted_buf needs
+        // to be owned by the closure.
+        let adapted_data = unsafe { data_from_vec(&mut adapted_buf) };
+        original_data_callback(&adapted_data, info);
+    })
+}
+
+/// When given an output data callback that expects a place to write samples in the specified
+/// sample format, return an output data callback that expects a place to write samples in the I16
+/// sample format. The `buffer_size` is in samples.
+pub(super) fn output_adapter_callback<T, D>(
+    mut original_data_callback: D,
+    buffer_size: FrameCount,
+) -> Box<dyn FnMut(&mut Data, &OutputCallbackInfo) + Send + 'static>
+where
+    D: FnMut(&mut Data, &OutputCallbackInfo) + Send + 'static,
+    T: Sample + TypeSampleFormat + Copy + Send + Default + 'static,
+{
+    let mut adapted_buf = vec![T::default(); buffer_size as usize];
+    Box::new(move |data: &mut Data, info: &OutputCallbackInfo| {
+        // Note: we construct adapted_data here instead of in the parent function because
+        // adapted_buf needs to be owned by the closure.
+        let mut adapted_data = unsafe { data_from_vec(&mut adapted_buf) };
+
+        // Populate adapted_buf / adapted_data.
+        original_data_callback(&mut adapted_data, info);
+
+        let data_slice: &mut [i16] = data.as_slice_mut().unwrap(); // unwrap OK because data is always i16
+        let adapted_slice = &adapted_buf;
+        assert_eq!(data_slice.len(), adapted_slice.len());
+        for (data_ref, adapted_element) in data_slice.iter_mut().zip(adapted_slice.iter()) {
+            *data_ref = adapted_element.to_i16();
+        }
+    })
+}
+
+unsafe fn data_from_vec<T>(adapted_buf: &mut Vec<T>) -> Data
+where
+    T: TypeSampleFormat,
+{
+    Data::from_parts(
+        adapted_buf.as_mut_ptr() as *mut _,
+        adapted_buf.len(), // TODO: this is converting a FrameCount to a number of samples; invalid for stereo!
+        T::sample_format(),
+    )
+}