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Remove EventLoop and port the ALSA backend

This commit is contained in:
Tatsuyuki Ishi 2019-07-09 15:47:33 +09:00 committed by mitchmindtree
parent 700bef79d9
commit c97d1dd3fa
8 changed files with 519 additions and 951 deletions
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26
examples/beep.rs
View File

@ -1,37 +1,34 @@
extern crate anyhow;
extern crate cpal;
use cpal::traits::{DeviceTrait, EventLoopTrait, HostTrait};
use cpal::traits::{DeviceTrait, StreamTrait, HostTrait};
fn main() -> Result<(), anyhow::Error> {
let host = cpal::default_host();
let device = host.default_output_device().expect("failed to find a default output device");
let format = device.default_output_format()?;
let event_loop = host.event_loop();
let stream_id = event_loop.build_output_stream(&device, &format)?;
event_loop.play_stream(stream_id.clone())?;
let sample_rate = format.sample_rate.0 as f32;
let channels = format.channels;
let mut sample_clock = 0f32;
// Produce a sinusoid of maximum amplitude.
let mut next_value = || {
let mut next_value = move || {
sample_clock = (sample_clock + 1.0) % sample_rate;
(sample_clock * 440.0 * 2.0 * 3.141592 / sample_rate).sin()
};
event_loop.run(move |id, result| {
let stream = device.build_output_stream(&format, move |result| {
let data = match result {
Ok(data) => data,
Err(err) => {
eprintln!("an error occurred on stream {:?}: {}", id, err);
eprintln!("an error occurred on stream: {}", err);
return;
}
};
match data {
cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::U16(mut buffer) } => {
for sample in buffer.chunks_mut(format.channels as usize) {
for sample in buffer.chunks_mut(channels as usize) {
let value = ((next_value() * 0.5 + 0.5) * std::u16::MAX as f32) as u16;
for out in sample.iter_mut() {
*out = value;
@ -39,7 +36,7 @@ fn main() -> Result<(), anyhow::Error> {
}
},
cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::I16(mut buffer) } => {
for sample in buffer.chunks_mut(format.channels as usize) {
for sample in buffer.chunks_mut(channels as usize) {
let value = (next_value() * std::i16::MAX as f32) as i16;
for out in sample.iter_mut() {
*out = value;
@ -47,7 +44,7 @@ fn main() -> Result<(), anyhow::Error> {
}
},
cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::F32(mut buffer) } => {
for sample in buffer.chunks_mut(format.channels as usize) {
for sample in buffer.chunks_mut(channels as usize) {
let value = next_value();
for out in sample.iter_mut() {
*out = value;
@ -56,5 +53,10 @@ fn main() -> Result<(), anyhow::Error> {
},
_ => (),
}
});
})?;
stream.play()?;
std::thread::sleep(std::time::Duration::from_millis(1000));
Ok(())
}

74
examples/feedback.rs
View File

@ -10,18 +10,21 @@ extern crate anyhow;
extern crate cpal;
extern crate ringbuf;
use cpal::traits::{DeviceTrait, EventLoopTrait, HostTrait};
use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
use ringbuf::RingBuffer;
const LATENCY_MS: f32 = 150.0;
fn main() -> Result<(), anyhow::Error> {
let host = cpal::default_host();
let event_loop = host.event_loop();
// Default devices.
let input_device = host.default_input_device().expect("failed to get default input device");
let output_device = host.default_output_device().expect("failed to get default output device");
let input_device = host
.default_input_device()
.expect("failed to get default input device");
let output_device = host
.default_output_device()
.expect("failed to get default output device");
println!("Using default input device: \"{}\"", input_device.name()?);
println!("Using default output device: \"{}\"", output_device.name()?);
@ -29,12 +32,6 @@ fn main() -> Result<(), anyhow::Error> {
let mut format = input_device.default_input_format()?;
format.data_type = cpal::SampleFormat::F32;
// Build streams.
println!("Attempting to build both streams with `{:?}`.", format);
let input_stream_id = event_loop.build_input_stream(&input_device, &format)?;
let output_stream_id = event_loop.build_output_stream(&output_device, &format)?;
println!("Successfully built streams.");
// Create a delay in case the input and output devices aren't synced.
let latency_frames = (LATENCY_MS / 1_000.0) * format.sample_rate.0 as f32;
let latency_samples = latency_frames as usize * format.channels as usize;
@ -50,25 +47,21 @@ fn main() -> Result<(), anyhow::Error> {
producer.push(0.0).unwrap();
}
// Play the streams.
println!("Starting the input and output streams with `{}` milliseconds of latency.", LATENCY_MS);
event_loop.play_stream(input_stream_id.clone())?;
event_loop.play_stream(output_stream_id.clone())?;
// Run the event loop on a separate thread.
std::thread::spawn(move || {
event_loop.run(move |id, result| {
// Build streams.
println!("Attempting to build both streams with `{:?}`.", format);
let input_stream = input_device.build_input_stream(&format, move |result| {
let data = match result {
Ok(data) => data,
Err(err) => {
eprintln!("an error occurred on stream {:?}: {}", id, err);
eprintln!("an error occurred on input stream: {}", err);
return;
}
},
};
match data {
cpal::StreamData::Input { buffer: cpal::UnknownTypeInputBuffer::F32(buffer) } => {
assert_eq!(id, input_stream_id);
cpal::StreamData::Input {
buffer: cpal::UnknownTypeInputBuffer::F32(buffer),
} => {
let mut output_fell_behind = false;
for &sample in buffer.iter() {
if producer.push(sample).is_err() {
@ -79,8 +72,21 @@ fn main() -> Result<(), anyhow::Error> {
eprintln!("output stream fell behind: try increasing latency");
}
},
cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::F32(mut buffer) } => {
assert_eq!(id, output_stream_id);
_ => panic!("Expected input with f32 data"),
}
})?;
let output_stream = output_device.build_output_stream(&format, move |result| {
let data = match result {
Ok(data) => data,
Err(err) => {
eprintln!("an error occurred on output stream: {}", err);
return;
},
};
match data {
cpal::StreamData::Output {
buffer: cpal::UnknownTypeOutputBuffer::F32(mut buffer),
} => {
let mut input_fell_behind = None;
for sample in buffer.iter_mut() {
*sample = match consumer.pop() {
@ -91,18 +97,28 @@ fn main() -> Result<(), anyhow::Error> {
},
};
}
if let Some(_) = input_fell_behind {
eprintln!("input stream fell behind: try increasing latency");
if let Some(err) = input_fell_behind {
eprintln!("input stream fell behind: {:?}: try increasing latency", err);
}
},
_ => panic!("we're expecting f32 data"),
_ => panic!("Expected output with f32 data"),
}
});
});
})?;
println!("Successfully built streams.");
// Play the streams.
println!(
"Starting the input and output streams with `{}` milliseconds of latency.",
LATENCY_MS
);
input_stream.play()?;
output_stream.play()?;
// Run for 3 seconds before closing.
println!("Playing for 3 seconds... ");
std::thread::sleep(std::time::Duration::from_secs(3));
drop(input_stream);
drop(output_stream);
println!("Done!");
Ok(())
}

45
examples/record_wav.rs
View File

@ -6,21 +6,21 @@ extern crate anyhow;
extern crate cpal;
extern crate hound;
use cpal::traits::{DeviceTrait, EventLoopTrait, HostTrait};
use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
fn main() -> Result<(), anyhow::Error> {
// Use the default host for working with audio devices.
let host = cpal::default_host();
// Setup the default input device and stream with the default input format.
let device = host.default_input_device().expect("Failed to get default input device");
let device = host
.default_input_device()
.expect("Failed to get default input device");
println!("Default input device: {}", device.name()?);
let format = device.default_input_format().expect("Failed to get default input format");
let format = device
.default_input_format()
.expect("Failed to get default input format");
println!("Default input format: {:?}", format);
let event_loop = host.event_loop();
let stream_id = event_loop.build_input_stream(&device, &format)?;
event_loop.play_stream(stream_id)?;
// The WAV file we're recording to.
const PATH: &'static str = concat!(env!("CARGO_MANIFEST_DIR"), "/recorded.wav");
let spec = wav_spec_from_format(&format);
@ -29,28 +29,23 @@ fn main() -> Result<(), anyhow::Error> {
// A flag to indicate that recording is in progress.
println!("Begin recording...");
let recording = std::sync::Arc::new(std::sync::atomic::AtomicBool::new(true));
// Run the input stream on a separate thread.
let writer_2 = writer.clone();
let recording_2 = recording.clone();
std::thread::spawn(move || {
event_loop.run(move |id, event| {
let stream = device.build_input_stream(&format, move |event| {
let data = match event {
Ok(data) => data,
Err(err) => {
eprintln!("an error occurred on stream {:?}: {}", id, err);
eprintln!("an error occurred on stream: {}", err);
return;
}
},
};
// If we're done recording, return early.
if !recording_2.load(std::sync::atomic::Ordering::Relaxed) {
return;
}
// Otherwise write to the wav writer.
match data {
cpal::StreamData::Input { buffer: cpal::UnknownTypeInputBuffer::U16(buffer) } => {
cpal::StreamData::Input {
buffer: cpal::UnknownTypeInputBuffer::U16(buffer),
} => {
if let Ok(mut guard) = writer_2.try_lock() {
if let Some(writer) = guard.as_mut() {
for sample in buffer.iter() {
@ -60,7 +55,9 @@ fn main() -> Result<(), anyhow::Error> {
}
}
},
cpal::StreamData::Input { buffer: cpal::UnknownTypeInputBuffer::I16(buffer) } => {
cpal::StreamData::Input {
buffer: cpal::UnknownTypeInputBuffer::I16(buffer),
} => {
if let Ok(mut guard) = writer_2.try_lock() {
if let Some(writer) = guard.as_mut() {
for &sample in buffer.iter() {
@ -69,7 +66,9 @@ fn main() -> Result<(), anyhow::Error> {
}
}
},
cpal::StreamData::Input { buffer: cpal::UnknownTypeInputBuffer::F32(buffer) } => {
cpal::StreamData::Input {
buffer: cpal::UnknownTypeInputBuffer::F32(buffer),
} => {
if let Ok(mut guard) = writer_2.try_lock() {
if let Some(writer) = guard.as_mut() {
for &sample in buffer.iter() {
@ -80,12 +79,12 @@ fn main() -> Result<(), anyhow::Error> {
},
_ => (),
}
});
});
})?;
stream.play()?;
// Let recording go for roughly three seconds.
std::thread::sleep(std::time::Duration::from_secs(3));
recording.store(false, std::sync::atomic::Ordering::Relaxed);
drop(stream);
writer.lock().unwrap().take().unwrap().finalize()?;
println!("Recording {} complete!", PATH);
Ok(())

721
src/host/alsa/mod.rs
View File

@ -1,11 +1,14 @@
extern crate alsa_sys as alsa;
extern crate libc;
pub use self::enumerate::{Devices, default_input_device, default_output_device};
use std::{cmp, ffi, io, mem, ptr};
use std::sync::Arc;
use std::thread::{self, JoinHandle};
use std::vec::IntoIter as VecIntoIter;
use ChannelCount;
use BackendSpecificError;
use BuildStreamError;
use ChannelCount;
use DefaultFormatError;
use DeviceNameError;
use DevicesError;
@ -14,20 +17,15 @@ use PauseStreamError;
use PlayStreamError;
use SampleFormat;
use SampleRate;
use SupportedFormatsError;
use StreamData;
use StreamDataResult;
use StreamError;
use SupportedFormat;
use SupportedFormatsError;
use traits::{DeviceTrait, HostTrait, StreamTrait};
use UnknownTypeInputBuffer;
use UnknownTypeOutputBuffer;
use traits::{DeviceTrait, EventLoopTrait, HostTrait, StreamIdTrait};
use std::{cmp, ffi, ptr};
use std::sync::Mutex;
use std::sync::mpsc::{channel, Sender, Receiver};
use std::sync::atomic::{AtomicUsize, Ordering};
use std::vec::IntoIter as VecIntoIter;
pub use self::enumerate::{default_input_device, default_output_device, Devices};
pub type SupportedInputFormats = VecIntoIter<SupportedFormat>;
pub type SupportedOutputFormats = VecIntoIter<SupportedFormat>;
@ -47,7 +45,6 @@ impl Host {
impl HostTrait for Host {
type Devices = Devices;
type Device = Device;
type EventLoop = EventLoop;
fn is_available() -> bool {
// Assume ALSA is always available on linux/freebsd.
@ -65,15 +62,12 @@ impl HostTrait for Host {
fn default_output_device(&self) -> Option<Self::Device> {
default_output_device()
}
fn event_loop(&self) -> Self::EventLoop {
EventLoop::new()
}
}
impl DeviceTrait for Device {
type SupportedInputFormats = SupportedInputFormats;
type SupportedOutputFormats = SupportedOutputFormats;
type Stream = Stream;
fn name(&self) -> Result<String, DeviceNameError> {
Device::name(self)
@ -94,95 +88,132 @@ impl DeviceTrait for Device {
fn default_output_format(&self) -> Result<Format, DefaultFormatError> {
Device::default_output_format(self)
}
}
impl EventLoopTrait for EventLoop {
type Device = Device;
type StreamId = StreamId;
fn build_input_stream(
&self,
device: &Self::Device,
format: &Format,
) -> Result<Self::StreamId, BuildStreamError> {
EventLoop::build_input_stream(self, device, format)
fn build_input_stream<F>(&self, format: &Format, callback: F) -> Result<Self::Stream, BuildStreamError> where F: FnMut(StreamDataResult) + Send + 'static {
Ok(Stream::new(Arc::new(self.build_stream_inner(format, alsa::SND_PCM_STREAM_CAPTURE)?), callback))
}
fn build_output_stream(
&self,
device: &Self::Device,
format: &Format,
) -> Result<Self::StreamId, BuildStreamError> {
EventLoop::build_output_stream(self, device, format)
}
fn play_stream(&self, stream: Self::StreamId) -> Result<(), PlayStreamError> {
EventLoop::play_stream(self, stream)
}
fn pause_stream(&self, stream: Self::StreamId) -> Result<(), PauseStreamError> {
EventLoop::pause_stream(self, stream)
}
fn destroy_stream(&self, stream: Self::StreamId) {
EventLoop::destroy_stream(self, stream)
}
fn run<F>(&self, callback: F) -> !
where
F: FnMut(Self::StreamId, StreamDataResult) + Send,
{
EventLoop::run(self, callback)
fn build_output_stream<F>(&self, format: &Format, callback: F) -> Result<Self::Stream, BuildStreamError> where F: FnMut(StreamDataResult) + Send + 'static {
Ok(Stream::new(Arc::new(self.build_stream_inner(format, alsa::SND_PCM_STREAM_PLAYBACK)?), callback))
}
}
impl StreamIdTrait for StreamId {}
struct Trigger {
// [read fd, write fd]
fds: [libc::c_int; 2],
}
struct TriggerSender(libc::c_int);
impl Trigger {
fn new() -> Self {
let mut fds = [0, 0];
match unsafe { libc::pipe(fds.as_mut_ptr()) } {
0 => Trigger { fds: fds },
_ => panic!("Could not create pipe"),
}
}
fn read_fd(&self) -> libc::c_int {
self.fds[0]
}
fn write_fd(&self) -> libc::c_int {
self.fds[1]
}
struct TriggerReceiver(libc::c_int);
impl TriggerSender {
fn wakeup(&self) {
let buf = 1u64;
let ret = unsafe { libc::write(self.write_fd(), &buf as *const u64 as *const _, 8) };
let ret = unsafe { libc::write(self.0, &buf as *const u64 as *const _, 8) };
assert!(ret == 8);
}
}
impl TriggerReceiver {
fn clear_pipe(&self) {
let mut out = 0u64;
let ret = unsafe { libc::read(self.read_fd(), &mut out as *mut u64 as *mut _, 8) };
let ret = unsafe { libc::read(self.0, &mut out as *mut u64 as *mut _, 8) };
assert_eq!(ret, 8);
}
}
impl Drop for Trigger {
fn trigger() -> (TriggerSender, TriggerReceiver) {
let mut fds = [0, 0];
match unsafe { libc::pipe(fds.as_mut_ptr()) } {
0 => (TriggerSender(fds[1]), TriggerReceiver(fds[0])),
_ => panic!("Could not create pipe"),
}
}
impl Drop for TriggerSender {
fn drop(&mut self) {
unsafe {
libc::close(self.fds[0]);
libc::close(self.fds[1]);
libc::close(self.0);
}
}
}
impl Drop for TriggerReceiver {
fn drop(&mut self) {
unsafe {
libc::close(self.0);
}
}
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Device(String);
impl Device {
fn build_stream_inner(&self, format: &Format, stream_type: alsa::snd_pcm_stream_t) -> Result<StreamInner, BuildStreamError> {
let name = ffi::CString::new(self.0.clone()).expect("unable to clone device");
let handle = unsafe {
let mut handle = ptr::null_mut();
match alsa::snd_pcm_open(
&mut handle,
name.as_ptr(),
stream_type,
alsa::SND_PCM_NONBLOCK,
) {
-16 /* determined empirically */ => return Err(BuildStreamError::DeviceNotAvailable),
-22 => return Err(BuildStreamError::InvalidArgument),
e => if let Err(description) = check_errors(e) {
let err = BackendSpecificError { description };
return Err(err.into());
}
}
handle
};
let can_pause = unsafe {
let hw_params = HwParams::alloc();
set_hw_params_from_format(handle, &hw_params, format)
.map_err(|description| BackendSpecificError { description })?;
alsa::snd_pcm_hw_params_can_pause(hw_params.0) == 1
};
let (buffer_len, period_len) = unsafe {
set_sw_params_from_format(handle, format)
.map_err(|description| BackendSpecificError { description })?
};
if let Err(desc) = check_errors(unsafe { alsa::snd_pcm_prepare(handle) }) {
let description = format!("could not get handle: {}", desc);
let err = BackendSpecificError { description };
return Err(err.into());
}
let num_descriptors = {
let num_descriptors = unsafe { alsa::snd_pcm_poll_descriptors_count(handle) };
if num_descriptors == 0 {
let description = "poll descriptor count for stream was 0".to_string();
let err = BackendSpecificError { description };
return Err(err.into());
}
num_descriptors as usize
};
let stream_inner = StreamInner {
channel: handle,
sample_format: format.data_type,
num_descriptors,
num_channels: format.channels as u16,
buffer_len,
period_len,
can_pause,
};
if let Err(desc) = check_errors(unsafe { alsa::snd_pcm_start(handle) }) {
let description = format!("could not start stream: {}", desc);
let err = BackendSpecificError { description };
return Err(err.into());
}
Ok(stream_inner)
}
#[inline]
fn name(&self) -> Result<String, DeviceNameError> {
Ok(self.0.clone())
@ -450,48 +481,7 @@ impl Device {
}
}
pub struct EventLoop {
// Each newly-created stream gets a new ID from this counter. The counter is then incremented.
next_stream_id: AtomicUsize, // TODO: use AtomicU64 when stable?
// A trigger that uses a `pipe()` as backend. Signalled whenever a new command is ready, so
// that `poll()` can wake up and pick the changes.
pending_command_trigger: Trigger,
// This field is locked by the `run()` method.
// The mutex also ensures that only one thread at a time has `run()` running.
run_context: Mutex<RunContext>,
// Commands processed by the `run()` method that is currently running.
commands: Sender<Command>,
}
unsafe impl Send for EventLoop {
}
unsafe impl Sync for EventLoop {
}
enum Command {
NewStream(StreamInner),
PlayStream(StreamId),
PauseStream(StreamId),
DestroyStream(StreamId),
}
struct RunContext {
// Descriptors to wait for. Always contains `pending_command_trigger.read_fd()` as first element.
descriptors: Vec<libc::pollfd>,
// List of streams that are written in `descriptors`.
streams: Vec<StreamInner>,
commands: Receiver<Command>,
}
struct StreamInner {
// The id of the stream.
id: StreamId,
// The ALSA channel.
channel: *mut alsa::snd_pcm_t,
@ -513,209 +503,174 @@ struct StreamInner {
// Whether or not the hardware supports pausing the stream.
can_pause: bool,
// Whether or not the sample stream is currently paused.
is_paused: bool,
// A file descriptor opened with `eventfd`.
// It is used to wait for resume signal.
resume_trigger: Trigger,
// Lazily allocated buffer that is reused inside the loop.
// Zero-allocate a new buffer (the fastest way to have zeroed memory) at the first time this is
// used.
buffer: Vec<u8>,
}
#[derive(Copy, Debug, Clone, PartialEq, Eq, Hash)]
pub struct StreamId(usize);
// Assume that the ALSA library is built with thread safe option.
unsafe impl Send for StreamInner {}
unsafe impl Sync for StreamInner {}
enum StreamType { Input, Output }
pub struct Stream {
/// The high-priority audio processing thread calling callbacks.
/// Option used for moving out in destructor.
thread: Option<JoinHandle<()>>,
impl EventLoop {
#[inline]
fn new() -> EventLoop {
let pending_command_trigger = Trigger::new();
/// Handle to the underlying stream for playback controls.
inner: Arc<StreamInner>,
let mut initial_descriptors = vec![];
reset_descriptors_with_pending_command_trigger(
&mut initial_descriptors,
&pending_command_trigger,
);
/// Used to signal to stop processing.
trigger: TriggerSender,
}
let (tx, rx) = channel();
let run_context = Mutex::new(RunContext {
descriptors: initial_descriptors,
streams: Vec::new(),
commands: rx,
/// The inner body of the audio processing thread. Takes the polymorphic
/// callback to avoid generating too much generic code.
fn stream_worker(rx: TriggerReceiver, stream: &StreamInner, callback: &mut (dyn FnMut(StreamDataResult) + Send + 'static)) {
let mut descriptors = Vec::new();
let mut buffer = Vec::new();
loop {
descriptors.clear();
// Add the self-pipe for signaling termination.
descriptors.push(libc::pollfd {
fd: rx.0,
events: libc::POLLIN,
revents: 0,
});
EventLoop {
next_stream_id: AtomicUsize::new(0),
pending_command_trigger: pending_command_trigger,
run_context,
commands: tx,
}
}
#[inline]
fn run<F>(&self, mut callback: F) -> !
where F: FnMut(StreamId, StreamDataResult)
{
self.run_inner(&mut callback)
}
fn run_inner(&self, callback: &mut dyn FnMut(StreamId, StreamDataResult)) -> ! {
// Add ALSA polling fds.
descriptors.reserve(stream.num_descriptors);
let len = descriptors.len();
let filled = unsafe {
alsa::snd_pcm_poll_descriptors(
stream.channel,
descriptors[len..].as_mut_ptr(),
stream.num_descriptors as libc::c_uint,
)
};
debug_assert_eq!(filled, stream.num_descriptors as libc::c_int);
unsafe {
let mut run_context = self.run_context.lock().unwrap();
let run_context = &mut *run_context;
'stream_loop: loop {
process_commands(run_context);
reset_descriptors_with_pending_command_trigger(
&mut run_context.descriptors,
&self.pending_command_trigger,
);
append_stream_poll_descriptors(run_context);
// At this point, this should include the command `pending_commands_trigger` along
// with the poll descriptors for each stream.
match poll_all_descriptors(&mut run_context.descriptors) {
Ok(true) => (),
Ok(false) => continue,
Err(err) => {
for stream in run_context.streams.iter() {
let result = Err(err.clone().into());
callback(stream.id, result);
}
run_context.streams.clear();
break 'stream_loop;
}
descriptors.set_len(len + stream.num_descriptors);
}
// If the `pending_command_trigger` was signaled, we need to process the comands.
if run_context.descriptors[0].revents != 0 {
run_context.descriptors[0].revents = 0;
self.pending_command_trigger.clear_pipe();
let res = unsafe {
// Don't timeout, wait forever.
libc::poll(descriptors.as_mut_ptr(), descriptors.len() as libc::nfds_t, -1)
};
if res < 0 {
let description = format!("`libc::poll()` failed: {}", io::Error::last_os_error());
callback(Err(BackendSpecificError { description }.into()));
continue;
} else if res == 0 {
let description = String::from("`libc::poll()` spuriously returned");
callback(Err(BackendSpecificError { description }.into()));
continue;
}
// The set of streams that error within the following loop and should be removed.
let mut streams_to_remove: Vec<(StreamId, StreamError)> = vec![];
if descriptors[0].revents != 0 {
// The stream has been requested to be destroyed.
rx.clear_pipe();
return;
}
// Iterate over each individual stream/descriptor.
let mut i_stream = 0;
let mut i_descriptor = 1;
while (i_descriptor as usize) < run_context.descriptors.len() {
let stream = &mut run_context.streams[i_stream];
let stream_descriptor_ptr = run_context.descriptors.as_mut_ptr().offset(i_descriptor);
// Only go on if this event was a pollout or pollin event.
let stream_type = match check_for_pollout_or_pollin(stream, stream_descriptor_ptr) {
let stream_type = match check_for_pollout_or_pollin(stream, descriptors[1..].as_mut_ptr()) {
Ok(Some(ty)) => ty,
Ok(None) => {
i_descriptor += stream.num_descriptors as isize;
i_stream += 1;
// Nothing to process, poll again
continue;
},
Err(err) => {
streams_to_remove.push((stream.id, err.into()));
i_descriptor += stream.num_descriptors as isize;
i_stream += 1;
// TODO: signal errors
continue;
}
};
// Get the number of available samples for reading/writing.
let available_samples = match get_available_samples(stream) {
Ok(n) => n,
Err(err) => {
streams_to_remove.push((stream.id, err.into()));
i_descriptor += stream.num_descriptors as isize;
i_stream += 1;
let description = format!("Failed to query the number of available samples: {}", err);
callback(Err(BackendSpecificError { description }.into()));
continue;
}
};
// Only go on if there is at least `stream.period_len` samples.
if available_samples < stream.period_len {
i_descriptor += stream.num_descriptors as isize;
i_stream += 1;
continue;
}
// Prepare the data buffer.
let buffer_size = stream.sample_format.sample_size() * available_samples;
stream.buffer.resize(buffer_size, 0u8);
buffer.resize(buffer_size, 0u8);
let available_frames = available_samples / stream.num_channels as usize;
match stream_type {
StreamType::Input => {
let result = alsa::snd_pcm_readi(
let result = unsafe {
alsa::snd_pcm_readi(
stream.channel,
stream.buffer.as_mut_ptr() as *mut _,
buffer.as_mut_ptr() as *mut _,
available_frames as alsa::snd_pcm_uframes_t,
);
)
};
if let Err(err) = check_errors(result as _) {
let description = format!("`snd_pcm_readi` failed: {}", err);
let err = BackendSpecificError { description };
streams_to_remove.push((stream.id, err.into()));
callback(Err(BackendSpecificError { description }.into()));
continue;
}
let input_buffer = match stream.sample_format {
SampleFormat::I16 => UnknownTypeInputBuffer::I16(::InputBuffer {
buffer: cast_input_buffer(&mut stream.buffer),
buffer: unsafe { cast_input_buffer(&mut buffer) },
}),
SampleFormat::U16 => UnknownTypeInputBuffer::U16(::InputBuffer {
buffer: cast_input_buffer(&mut stream.buffer),
buffer: unsafe { cast_input_buffer(&mut buffer) },
}),
SampleFormat::F32 => UnknownTypeInputBuffer::F32(::InputBuffer {
buffer: cast_input_buffer(&mut stream.buffer),
buffer: unsafe { cast_input_buffer(&mut buffer) },
}),
};
let stream_data = StreamData::Input {
buffer: input_buffer,
};
callback(stream.id, Ok(stream_data));
callback(Ok(stream_data));
},
StreamType::Output => {
{
// We're now sure that we're ready to write data.
let output_buffer = match stream.sample_format {
SampleFormat::I16 => UnknownTypeOutputBuffer::I16(::OutputBuffer {
buffer: cast_output_buffer(&mut stream.buffer),
buffer: unsafe { cast_output_buffer(&mut buffer) },
}),
SampleFormat::U16 => UnknownTypeOutputBuffer::U16(::OutputBuffer {
buffer: cast_output_buffer(&mut stream.buffer),
buffer: unsafe { cast_output_buffer(&mut buffer) },
}),
SampleFormat::F32 => UnknownTypeOutputBuffer::F32(::OutputBuffer {
buffer: cast_output_buffer(&mut stream.buffer),
buffer: unsafe { cast_output_buffer(&mut buffer) },
}),
};
let stream_data = StreamData::Output {
buffer: output_buffer,
};
callback(stream.id, Ok(stream_data));
callback(Ok(stream_data));
}
loop {
let result = alsa::snd_pcm_writei(
let result = unsafe {
alsa::snd_pcm_writei(
stream.channel,
stream.buffer.as_ptr() as *const _,
buffer.as_ptr() as *const _,
available_frames as alsa::snd_pcm_uframes_t,
);
)
};
if result as i32 == -libc::EPIPE {
if result == -libc::EPIPE as i64 {
// buffer underrun
// TODO: Notify the user of this.
alsa::snd_pcm_recover(stream.channel, result as i32, 0);
unsafe { alsa::snd_pcm_recover(stream.channel, result as i32, 0) };
} else if let Err(err) = check_errors(result as _) {
let description = format!("`snd_pcm_writei` failed: {}", err);
let err = BackendSpecificError { description };
streams_to_remove.push((stream.id, err.into()));
callback(Err(BackendSpecificError { description }.into()));
continue;
} else if result as usize != available_frames {
let description = format!(
@ -724,8 +679,7 @@ impl EventLoop {
available_frames,
result,
);
let err = BackendSpecificError { description };
streams_to_remove.push((stream.id, err.into()));
callback(Err(BackendSpecificError { description }.into()));
continue;
} else {
break;
@ -734,280 +688,45 @@ impl EventLoop {
},
}
}
// Remove any streams that have errored and notify the user.
for (stream_id, err) in streams_to_remove {
run_context.streams.retain(|s| s.id != stream_id);
callback(stream_id, Err(err.into()));
}
}
}
panic!("`cpal::EventLoop::run` API currently disallows returning");
}
fn build_input_stream(
&self,
device: &Device,
format: &Format,
) -> Result<StreamId, BuildStreamError>
{
unsafe {
let name = ffi::CString::new(device.0.clone()).expect("unable to clone device");
let mut capture_handle = ptr::null_mut();
match alsa::snd_pcm_open(
&mut capture_handle,
name.as_ptr(),
alsa::SND_PCM_STREAM_CAPTURE,
alsa::SND_PCM_NONBLOCK,
) {
-16 /* determined empirically */ => return Err(BuildStreamError::DeviceNotAvailable),
-22 => return Err(BuildStreamError::InvalidArgument),
e => if let Err(description) = check_errors(e) {
let err = BackendSpecificError { description };
return Err(err.into());
}
}
let hw_params = HwParams::alloc();
set_hw_params_from_format(capture_handle, &hw_params, format)
.map_err(|description| BackendSpecificError { description })?;
let can_pause = alsa::snd_pcm_hw_params_can_pause(hw_params.0) == 1;
let (buffer_len, period_len) = set_sw_params_from_format(capture_handle, format)
.map_err(|description| BackendSpecificError { description })?;
if let Err(desc) = check_errors(alsa::snd_pcm_prepare(capture_handle)) {
let description = format!("could not get capture handle: {}", desc);
let err = BackendSpecificError { description };
return Err(err.into());
}
let num_descriptors = {
let num_descriptors = alsa::snd_pcm_poll_descriptors_count(capture_handle);
if num_descriptors == 0 {
let description = "poll descriptor count for capture stream was 0".to_string();
let err = BackendSpecificError { description };
return Err(err.into());
}
num_descriptors as usize
};
let new_stream_id = StreamId(self.next_stream_id.fetch_add(1, Ordering::Relaxed));
if new_stream_id.0 == usize::max_value() {
panic!("number of streams used has overflowed usize");
}
let stream_inner = StreamInner {
id: new_stream_id.clone(),
channel: capture_handle,
sample_format: format.data_type,
num_descriptors: num_descriptors,
num_channels: format.channels as u16,
buffer_len: buffer_len,
period_len: period_len,
can_pause: can_pause,
is_paused: false,
resume_trigger: Trigger::new(),
buffer: vec![],
};
if let Err(desc) = check_errors(alsa::snd_pcm_start(capture_handle)) {
let description = format!("could not start capture stream: {}", desc);
let err = BackendSpecificError { description };
return Err(err.into());
}
self.push_command(Command::NewStream(stream_inner));
Ok(new_stream_id)
}
}
fn build_output_stream(
&self,
device: &Device,
format: &Format,
) -> Result<StreamId, BuildStreamError>
{
unsafe {
let name = ffi::CString::new(device.0.clone()).expect("unable to clone device");
let mut playback_handle = ptr::null_mut();
match alsa::snd_pcm_open(
&mut playback_handle,
name.as_ptr(),
alsa::SND_PCM_STREAM_PLAYBACK,
alsa::SND_PCM_NONBLOCK,
) {
-16 /* determined empirically */ => return Err(BuildStreamError::DeviceNotAvailable),
-22 => return Err(BuildStreamError::InvalidArgument),
e => if let Err(description) = check_errors(e) {
let err = BackendSpecificError { description };
return Err(err.into())
}
}
let hw_params = HwParams::alloc();
set_hw_params_from_format(playback_handle, &hw_params, format)
.map_err(|description| BackendSpecificError { description })?;
let can_pause = alsa::snd_pcm_hw_params_can_pause(hw_params.0) == 1;
let (buffer_len, period_len) = set_sw_params_from_format(playback_handle, format)
.map_err(|description| BackendSpecificError { description })?;
if let Err(desc) = check_errors(alsa::snd_pcm_prepare(playback_handle)) {
let description = format!("could not get playback handle: {}", desc);
let err = BackendSpecificError { description };
return Err(err.into());
}
let num_descriptors = {
let num_descriptors = alsa::snd_pcm_poll_descriptors_count(playback_handle);
if num_descriptors == 0 {
let description = "poll descriptor count for playback stream was 0".to_string();
let err = BackendSpecificError { description };
return Err(err.into());
}
num_descriptors as usize
};
let new_stream_id = StreamId(self.next_stream_id.fetch_add(1, Ordering::Relaxed));
if new_stream_id.0 == usize::max_value() {
return Err(BuildStreamError::StreamIdOverflow);
}
let stream_inner = StreamInner {
id: new_stream_id.clone(),
channel: playback_handle,
sample_format: format.data_type,
num_descriptors: num_descriptors,
num_channels: format.channels as u16,
buffer_len: buffer_len,
period_len: period_len,
can_pause: can_pause,
is_paused: false,
resume_trigger: Trigger::new(),
buffer: vec![],
};
self.push_command(Command::NewStream(stream_inner));
Ok(new_stream_id)
}
}
#[inline]
fn push_command(&self, command: Command) {
// Safe to unwrap: sender outlives receiver.
self.commands.send(command).unwrap();
self.pending_command_trigger.wakeup();
}
#[inline]
fn destroy_stream(&self, stream_id: StreamId) {
self.push_command(Command::DestroyStream(stream_id));
}
#[inline]
fn play_stream(&self, stream_id: StreamId) -> Result<(), PlayStreamError> {
self.push_command(Command::PlayStream(stream_id));
Ok(())
}
#[inline]
fn pause_stream(&self, stream_id: StreamId) -> Result<(), PauseStreamError> {
self.push_command(Command::PauseStream(stream_id));
Ok(())
}
}
// Process any pending `Command`s within the `RunContext`'s queue.
fn process_commands(run_context: &mut RunContext) {
for command in run_context.commands.try_iter() {
match command {
Command::DestroyStream(stream_id) => {
run_context.streams.retain(|s| s.id != stream_id);
},
Command::PlayStream(stream_id) => {
if let Some(stream) = run_context.streams.iter_mut()
.find(|stream| stream.can_pause && stream.id == stream_id)
{
unsafe {
alsa::snd_pcm_pause(stream.channel, 0);
}
stream.is_paused = false;
}
},
Command::PauseStream(stream_id) => {
if let Some(stream) = run_context.streams.iter_mut()
.find(|stream| stream.can_pause && stream.id == stream_id)
{
unsafe {
alsa::snd_pcm_pause(stream.channel, 1);
}
stream.is_paused = true;
}
},
Command::NewStream(stream_inner) => {
run_context.streams.push(stream_inner);
},
}
}
}
// Resets the descriptors so that only `pending_command_trigger.read_fd()` is contained.
fn reset_descriptors_with_pending_command_trigger(
descriptors: &mut Vec<libc::pollfd>,
pending_command_trigger: &Trigger,
) {
descriptors.clear();
descriptors.push(libc::pollfd {
fd: pending_command_trigger.read_fd(),
events: libc::POLLIN,
revents: 0,
impl Stream {
fn new<F>(inner: Arc<StreamInner>, mut callback: F) -> Stream where F: FnMut(StreamDataResult) + Send + 'static {
let (tx, rx) = trigger();
// Clone the handle for passing into worker thread.
let stream = inner.clone();
let thread = thread::spawn(move || {
stream_worker(rx, &*stream, &mut callback);
});
Stream {
thread: Some(thread),
inner,
trigger: tx,
}
}
}
// Appends the `poll` descriptors for each stream onto the `RunContext`'s descriptor slice, ready
// for a call to `libc::poll`.
fn append_stream_poll_descriptors(run_context: &mut RunContext) {
for stream in run_context.streams.iter() {
run_context.descriptors.reserve(stream.num_descriptors);
let len = run_context.descriptors.len();
let filled = unsafe {
alsa::snd_pcm_poll_descriptors(
stream.channel,
run_context.descriptors.as_mut_ptr().offset(len as isize),
stream.num_descriptors as libc::c_uint,
)
};
debug_assert_eq!(filled, stream.num_descriptors as libc::c_int);
impl Drop for Stream {
fn drop(&mut self) {
self.trigger.wakeup();
self.thread.take().unwrap().join().unwrap();
}
}
impl StreamTrait for Stream {
fn play(&self) -> Result<(), PlayStreamError> {
unsafe {
run_context.descriptors.set_len(len + stream.num_descriptors);
alsa::snd_pcm_pause(self.inner.channel, 0);
}
// TODO: error handling
Ok(())
}
}
// Poll all descriptors within the given set.
//
// Returns `Ok(true)` if some event has occurred or `Ok(false)` if no events have
// occurred.
//
// Returns an `Err` if `libc::poll` returns a negative value for some reason.
fn poll_all_descriptors(descriptors: &mut [libc::pollfd]) -> Result<bool, BackendSpecificError> {
let res = unsafe {
// Don't timeout, wait forever.
libc::poll(descriptors.as_mut_ptr(), descriptors.len() as libc::nfds_t, -1)
};
if res < 0 {
let description = format!("`libc::poll()` failed: {}", res);
Err(BackendSpecificError { description })
} else if res == 0 {
Ok(false)
} else {
Ok(true)
fn pause(&self)-> Result<(), PauseStreamError> {
unsafe {
alsa::snd_pcm_pause(self.inner.channel, 1);
}
// TODO: error handling
Ok(())
}
}

58
src/host/null/mod.rs
View File

@ -10,7 +10,7 @@ use PlayStreamError;
use StreamDataResult;
use SupportedFormatsError;
use SupportedFormat;
use traits::{DeviceTrait, EventLoopTrait, HostTrait, StreamIdTrait};
use traits::{DeviceTrait, HostTrait, StreamTrait};
#[derive(Default)]
pub struct Devices;
@ -23,7 +23,7 @@ pub struct EventLoop;
pub struct Host;
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct StreamId;
pub struct Stream;
pub struct SupportedInputFormats;
pub struct SupportedOutputFormats;
@ -49,6 +49,7 @@ impl EventLoop {
impl DeviceTrait for Device {
type SupportedInputFormats = SupportedInputFormats;
type SupportedOutputFormats = SupportedOutputFormats;
type Stream = Stream;
#[inline]
fn name(&self) -> Result<String, DeviceNameError> {
@ -74,49 +75,22 @@ impl DeviceTrait for Device {
fn default_output_format(&self) -> Result<Format, DefaultFormatError> {
unimplemented!()
}
}
impl EventLoopTrait for EventLoop {
type Device = Device;
type StreamId = StreamId;
#[inline]
fn run<F>(&self, _callback: F) -> !
where F: FnMut(StreamId, StreamDataResult)
{
loop { /* TODO: don't spin */ }
}
#[inline]
fn build_input_stream(&self, _: &Device, _: &Format) -> Result<StreamId, BuildStreamError> {
Err(BuildStreamError::DeviceNotAvailable)
}
#[inline]
fn build_output_stream(&self, _: &Device, _: &Format) -> Result<StreamId, BuildStreamError> {
Err(BuildStreamError::DeviceNotAvailable)
}
#[inline]
fn destroy_stream(&self, _: StreamId) {
fn build_input_stream<F>(&self, format: &Format, callback: F) -> Result<Self::Stream, BuildStreamError>
where F: FnMut(StreamDataResult) + Send + 'static {
unimplemented!()
}
#[inline]
fn play_stream(&self, _: StreamId) -> Result<(), PlayStreamError> {
panic!()
}
#[inline]
fn pause_stream(&self, _: StreamId) -> Result<(), PauseStreamError> {
panic!()
/// Create an output stream.
fn build_output_stream<F>(&self, format: &Format, callback: F) -> Result<Self::Stream, BuildStreamError>
where F: FnMut(StreamDataResult) + Send + 'static{
unimplemented!()
}
}
impl HostTrait for Host {
type Device = Device;
type Devices = Devices;
type EventLoop = EventLoop;
fn is_available() -> bool {
false
@ -133,13 +107,17 @@ impl HostTrait for Host {
fn default_output_device(&self) -> Option<Device> {
None
}
fn event_loop(&self) -> Self::EventLoop {
EventLoop::new()
}
}
impl StreamIdTrait for StreamId {}
impl StreamTrait for Stream {
fn play(&self) -> Result<(), PlayStreamError> {
unimplemented!()
}
fn pause(&self) -> Result<(), PauseStreamError> {
unimplemented!()
}
}
impl Iterator for Devices {
type Item = Device;

5
src/lib.rs
View File

@ -151,11 +151,10 @@ extern crate thiserror;
pub use error::*;
pub use platform::{
ALL_HOSTS, Device, Devices, EventLoop, Host, HostId, SupportedInputFormats,
SupportedOutputFormats, StreamId, available_hosts, default_host, host_from_id,
ALL_HOSTS, available_hosts, default_host, Device, Devices, Host, host_from_id,
HostId, Stream, SupportedInputFormats, SupportedOutputFormats,
};
pub use samples_formats::{Sample, SampleFormat};
use std::ops::{Deref, DerefMut};
mod error;

160
src/platform/mod.rs
View File

@ -58,14 +58,9 @@ macro_rules! impl_platform_host {
/// type.
pub struct Devices(DevicesInner);
/// The **EventLoop** implementation associated with the platform's dynamically dispatched
/// The **Stream** implementation associated with the platform's dynamically dispatched
/// **Host** type.
pub struct EventLoop(EventLoopInner);
/// The **StreamId** implementation associated with the platform's dynamically dispatched
/// **Host** type.
#[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub struct StreamId(StreamIdInner);
pub struct Stream(StreamInner);
/// The **SupportedInputFormats** iterator associated with the platform's dynamically
/// dispatched **Host** type.
@ -95,22 +90,15 @@ macro_rules! impl_platform_host {
)*
}
enum EventLoopInner {
$(
$HostVariant(crate::host::$host_mod::EventLoop),
)*
}
enum HostInner {
$(
$HostVariant(crate::host::$host_mod::Host),
)*
}
#[derive(Clone, Debug, Eq, Hash, PartialEq)]
enum StreamIdInner {
enum StreamInner {
$(
$HostVariant(crate::host::$host_mod::StreamId),
$HostVariant(crate::host::$host_mod::Stream),
)*
}
@ -212,6 +200,7 @@ macro_rules! impl_platform_host {
impl crate::traits::DeviceTrait for Device {
type SupportedInputFormats = SupportedInputFormats;
type SupportedOutputFormats = SupportedOutputFormats;
type Stream = Stream;
fn name(&self) -> Result<String, crate::DeviceNameError> {
match self.0 {
@ -260,96 +249,25 @@ macro_rules! impl_platform_host {
)*
}
}
}
impl crate::traits::EventLoopTrait for EventLoop {
type StreamId = StreamId;
type Device = Device;
#[allow(unreachable_patterns)]
fn build_input_stream(
&self,
device: &Self::Device,
format: &crate::Format,
) -> Result<Self::StreamId, crate::BuildStreamError> {
match (&self.0, &device.0) {
$(
(&EventLoopInner::$HostVariant(ref e), &DeviceInner::$HostVariant(ref d)) => {
e.build_input_stream(d, format)
.map(StreamIdInner::$HostVariant)
.map(StreamId)
}
)*
_ => panic!("tried to build a stream with a device from another host"),
}
}
#[allow(unreachable_patterns)]
fn build_output_stream(
&self,
device: &Self::Device,
format: &crate::Format,
) -> Result<Self::StreamId, crate::BuildStreamError> {
match (&self.0, &device.0) {
$(
(&EventLoopInner::$HostVariant(ref e), &DeviceInner::$HostVariant(ref d)) => {
e.build_output_stream(d, format)
.map(StreamIdInner::$HostVariant)
.map(StreamId)
}
)*
_ => panic!("tried to build a stream with a device from another host"),
}
}
#[allow(unreachable_patterns)]
fn play_stream(&self, stream: Self::StreamId) -> Result<(), crate::PlayStreamError> {
match (&self.0, stream.0) {
$(
(&EventLoopInner::$HostVariant(ref e), StreamIdInner::$HostVariant(ref s)) => {
e.play_stream(s.clone())
}
)*
_ => panic!("tried to play a stream with an ID associated with another host"),
}
}
#[allow(unreachable_patterns)]
fn pause_stream(&self, stream: Self::StreamId) -> Result<(), crate::PauseStreamError> {
match (&self.0, stream.0) {
$(
(&EventLoopInner::$HostVariant(ref e), StreamIdInner::$HostVariant(ref s)) => {
e.pause_stream(s.clone())
}
)*
_ => panic!("tried to pause a stream with an ID associated with another host"),
}
}
#[allow(unreachable_patterns)]
fn destroy_stream(&self, stream: Self::StreamId) {
match (&self.0, stream.0) {
$(
(&EventLoopInner::$HostVariant(ref e), StreamIdInner::$HostVariant(ref s)) => {
e.destroy_stream(s.clone())
}
)*
_ => panic!("tried to destroy a stream with an ID associated with another host"),
}
}
fn run<F>(&self, mut callback: F) -> !
where
F: FnMut(Self::StreamId, crate::StreamDataResult) + Send
{
fn build_input_stream<F>(&self, format: &crate::Format, callback: F) -> Result<Self::Stream, crate::BuildStreamError>
where F: FnMut(crate::StreamDataResult) + Send + 'static {
match self.0 {
$(
EventLoopInner::$HostVariant(ref e) => {
e.run(|id, result| {
let result = result;
callback(StreamId(StreamIdInner::$HostVariant(id)), result);
});
},
DeviceInner::$HostVariant(ref d) => d.build_input_stream(format, callback)
.map(StreamInner::$HostVariant)
.map(Stream),
)*
}
}
fn build_output_stream<F>(&self, format: &crate::Format, callback: F) -> Result<Self::Stream, crate::BuildStreamError>
where F: FnMut(crate::StreamDataResult) + Send + 'static {
match self.0 {
$(
DeviceInner::$HostVariant(ref d) => d.build_output_stream(format, callback)
.map(StreamInner::$HostVariant)
.map(Stream),
)*
}
}
@ -358,7 +276,6 @@ macro_rules! impl_platform_host {
impl crate::traits::HostTrait for Host {
type Devices = Devices;
type Device = Device;
type EventLoop = EventLoop;
fn is_available() -> bool {
$( crate::host::$host_mod::Host::is_available() ||)* false
@ -393,20 +310,30 @@ macro_rules! impl_platform_host {
)*
}
}
}
fn event_loop(&self) -> Self::EventLoop {
impl crate::traits::StreamTrait for Stream {
fn play(&self) -> Result<(), crate::PlayStreamError> {
match self.0 {
$(
HostInner::$HostVariant(ref h) => {
EventLoop(EventLoopInner::$HostVariant(h.event_loop()))
StreamInner::$HostVariant(ref s) => {
s.play()
}
)*
}
}
fn pause(&self) -> Result<(), crate::PauseStreamError> {
match self.0 {
$(
StreamInner::$HostVariant(ref s) => {
s.pause()
}
)*
}
}
}
impl crate::traits::StreamIdTrait for StreamId {}
$(
impl From<crate::host::$host_mod::Device> for Device {
fn from(h: crate::host::$host_mod::Device) -> Self {
@ -420,21 +347,15 @@ macro_rules! impl_platform_host {
}
}
impl From<crate::host::$host_mod::EventLoop> for EventLoop {
fn from(h: crate::host::$host_mod::EventLoop) -> Self {
EventLoop(EventLoopInner::$HostVariant(h))
}
}
impl From<crate::host::$host_mod::Host> for Host {
fn from(h: crate::host::$host_mod::Host) -> Self {
Host(HostInner::$HostVariant(h))
}
}
impl From<crate::host::$host_mod::StreamId> for StreamId {
fn from(h: crate::host::$host_mod::StreamId) -> Self {
StreamId(StreamIdInner::$HostVariant(h))
impl From<crate::host::$host_mod::Stream> for Stream {
fn from(h: crate::host::$host_mod::Stream) -> Self {
Stream(StreamInner::$HostVariant(h))
}
}
)*
@ -471,9 +392,8 @@ mod platform_impl {
pub use crate::host::alsa::{
Device as AlsaDevice,
Devices as AlsaDevices,
EventLoop as AlsaEventLoop,
Host as AlsaHost,
StreamId as AlsaStreamId,
Stream as AlsaStream,
SupportedInputFormats as AlsaSupportedInputFormats,
SupportedOutputFormats as AlsaSupportedOutputFormats,
};

93
src/traits.rs
View File

@ -39,8 +39,6 @@ pub trait HostTrait {
type Devices: Iterator<Item = Self::Device>;
/// The `Device` type yielded by the host.
type Device: DeviceTrait;
/// The event loop type used by the `Host`
type EventLoop: EventLoopTrait<Device = Self::Device>;
/// Whether or not the host is available on the system.
fn is_available() -> bool;
@ -60,9 +58,6 @@ pub trait HostTrait {
/// Returns `None` if no output device is available.
fn default_output_device(&self) -> Option<Self::Device>;
/// Initialise the event loop, ready for managing audio streams.
fn event_loop(&self) -> Self::EventLoop;
/// An iterator yielding all `Device`s currently available to the system that support one or more
/// input stream formats.
///
@ -99,6 +94,8 @@ pub trait DeviceTrait {
type SupportedInputFormats: Iterator<Item = SupportedFormat>;
/// The iterator type yielding supported output stream formats.
type SupportedOutputFormats: Iterator<Item = SupportedFormat>;
/// The stream type created by `build_input_stream` and `build_output_stream`.
type Stream: StreamTrait;
/// The human-readable name of the device.
fn name(&self) -> Result<String, DeviceNameError>;
@ -118,81 +115,19 @@ pub trait DeviceTrait {
/// The default output stream format for the device.
fn default_output_format(&self) -> Result<Format, DefaultFormatError>;
/// Create an input stream.
fn build_input_stream<F>(&self, format: &Format, callback: F) -> Result<Self::Stream, BuildStreamError>
where F: FnMut(StreamDataResult) + Send + 'static;
/// Create an output stream.
fn build_output_stream<F>(&self, format: &Format, callback: F) -> Result<Self::Stream, BuildStreamError>
where F: FnMut(StreamDataResult) + Send + 'static;
}
/// Collection of streams managed together.
///
/// Created with the `Host::event_loop` method.
pub trait EventLoopTrait {
/// The `Device` type yielded by the host.
type Device: DeviceTrait;
/// The type used to uniquely distinguish between streams.
type StreamId: StreamIdTrait;
/// A stream created from `Device`, with methods to control playback.
pub trait StreamTrait {
fn play(&self) -> Result<(), PlayStreamError>;
/// Creates a new input stream that will run from the given device and with the given format.
///
/// On success, returns an identifier for the stream.
///
/// Can return an error if the device is no longer valid, or if the input stream format is not
/// supported by the device.
fn build_input_stream(
&self,
device: &Self::Device,
format: &Format,
) -> Result<Self::StreamId, BuildStreamError>;
/// Creates a new output stream that will play on the given device and with the given format.
///
/// On success, returns an identifier for the stream.
///
/// Can return an error if the device is no longer valid, or if the output stream format is not
/// supported by the device.
fn build_output_stream(
&self,
device: &Self::Device,
format: &Format,
) -> Result<Self::StreamId, BuildStreamError>;
/// Instructs the audio device that it should start playing the stream with the given ID.
///
/// Has no effect is the stream was already playing.
///
/// Only call this after you have submitted some data, otherwise you may hear some glitches.
///
/// # Panic
///
/// If the stream does not exist, this function can either panic or be a no-op.
fn play_stream(&self, stream: Self::StreamId) -> Result<(), PlayStreamError>;
/// Instructs the audio device that it should stop playing the stream with the given ID.
///
/// Has no effect is the stream was already paused.
///
/// If you call `play` afterwards, the playback will resume where it was.
///
/// # Panic
///
/// If the stream does not exist, this function can either panic or be a no-op.
fn pause_stream(&self, stream: Self::StreamId) -> Result<(), PauseStreamError>;
/// Destroys an existing stream.
///
/// # Panic
///
/// If the stream does not exist, this function can either panic or be a no-op.
fn destroy_stream(&self, stream: Self::StreamId);
/// Takes control of the current thread and begins the stream processing.
///
/// > **Note**: Since it takes control of the thread, this method is best called on a separate
/// > thread.
///
/// Whenever a stream needs to be fed some data, the closure passed as parameter is called.
/// You can call the other methods of `EventLoop` without getting a deadlock.
fn run<F>(&self, callback: F) -> !
where
F: FnMut(Self::StreamId, StreamDataResult) + Send;
fn pause(&self) -> Result<(), PauseStreamError>;
}
/// The set of required bounds for host `StreamId` types.
pub trait StreamIdTrait: Clone + std::fmt::Debug + std::hash::Hash + PartialEq + Eq {}