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Draft for switching to futures

This commit is contained in:
Pierre Krieger 2016-08-02 16:13:59 +02:00
parent 47fec7e846
commit be8310da51
5 changed files with 322 additions and 184 deletions
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2
Cargo.toml
View File

@ -10,10 +10,12 @@ license = "Apache-2.0"
keywords = ["audio", "sound"]
[dependencies]
futures = { git = "https://github.com/alexcrichton/futures-rs" }
libc = "0.2"
lazy_static = "0.2"
winapi = "0.2.8"
ole32-sys = "0.2"
kernel32-sys = "0.2"
[target.arm-unknown-linux-gnueabihf.dependencies.alsa-sys]
version = "0"

27
examples/beep.rs
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@ -1,16 +1,25 @@
extern crate cpal;
extern crate futures;
use futures::Future;
use futures::stream::Stream;
fn main() {
let endpoint = cpal::get_default_endpoint().expect("Failed to get default endpoint");
let format = endpoint.get_supported_formats_list().unwrap().next().expect("Failed to get endpoint format");
let mut channel = cpal::Voice::new(&endpoint, &format).expect("Failed to create a channel");
let event_loop = cpal::EventLoop::new();
let (mut voice, stream) = cpal::Voice::new(&endpoint, &format, &event_loop).expect("Failed to create a voice");
// Produce a sinusoid of maximum amplitude.
let mut data_source = (0u64..).map(|t| t as f32 * 440.0 * 2.0 * 3.141592 / format.samples_rate.0 as f32) // 440 Hz
.map(|t| t.sin());
let samples_rate = format.samples_rate.0 as f32;
let mut data_source = (0u64..).map(move |t| t as f32 * 440.0 * 2.0 * 3.141592 / samples_rate) // 440 Hz
.map(move |t| t.sin());
loop {
match channel.append_data(32768) {
voice.play();
stream.for_each(move |buffer| -> Result<_, ()> {
match buffer {
cpal::UnknownTypeBuffer::U16(mut buffer) => {
for (sample, value) in buffer.chunks_mut(format.channels.len()).zip(&mut data_source) {
let value = ((value * 0.5 + 0.5) * std::u16::MAX as f32) as u16;
@ -30,8 +39,10 @@ fn main() {
for out in sample.iter_mut() { *out = value; }
}
},
}
};
channel.play();
}
Ok(())
}).forget();
event_loop.run();
}

122
src/lib.rs
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@ -37,6 +37,8 @@ reaches the end of the data, it will stop playing. You must continuously fill th
calling `append_data` repeatedly if you don't want the audio to stop playing.
*/
extern crate futures;
#[macro_use]
extern crate lazy_static;
extern crate libc;
@ -50,6 +52,10 @@ use std::fmt;
use std::error::Error;
use std::ops::{Deref, DerefMut};
use futures::stream::Stream;
use futures::Poll;
use futures::Task;
mod null;
mod samples_formats;
@ -169,29 +175,43 @@ impl Iterator for SupportedFormatsIterator {
}
}
pub struct EventLoop(cpal_impl::EventLoop);
impl EventLoop {
#[inline]
pub fn new() -> EventLoop {
EventLoop(cpal_impl::EventLoop::new())
}
#[inline]
pub fn run(&self) {
self.0.run()
}
}
/// Represents a buffer that must be filled with audio data.
///
/// You should destroy this object as soon as possible. Data is only committed when it
/// is destroyed.
#[must_use]
pub struct Buffer<'a, T: 'a> where T: Sample {
pub struct Buffer<T> where T: Sample {
// also contains something, taken by `Drop`
target: Option<cpal_impl::Buffer<'a, T>>,
target: Option<cpal_impl::Buffer<T>>,
}
/// This is the struct that is provided to you by cpal when you want to write samples to a buffer.
///
/// Since the type of data is only known at runtime, you have to fill the right buffer.
pub enum UnknownTypeBuffer<'a> {
pub enum UnknownTypeBuffer {
/// Samples whose format is `u16`.
U16(Buffer<'a, u16>),
U16(Buffer<u16>),
/// Samples whose format is `i16`.
I16(Buffer<'a, i16>),
I16(Buffer<i16>),
/// Samples whose format is `f32`.
F32(Buffer<'a, f32>),
F32(Buffer<f32>),
}
impl<'a> UnknownTypeBuffer<'a> {
impl UnknownTypeBuffer {
/// Returns the length of the buffer in number of samples.
#[inline]
pub fn len(&self) -> usize {
@ -282,13 +302,19 @@ pub struct Voice {
impl Voice {
/// Builds a new channel.
#[inline]
pub fn new(endpoint: &Endpoint, format: &Format) -> Result<Voice, CreationError> {
let channel = try!(cpal_impl::Voice::new(&endpoint.0, format));
pub fn new(endpoint: &Endpoint, format: &Format, event_loop: &EventLoop)
-> Result<(Voice, SamplesStream), CreationError>
{
let (voice, stream) = try!(cpal_impl::Voice::new(&endpoint.0, format, &event_loop.0));
Ok(Voice {
voice: channel,
let voice = Voice {
voice: voice,
format: format.clone(),
})
};
let stream = SamplesStream(stream);
Ok((voice, stream))
}
/// Returns the format used by the voice.
@ -324,51 +350,6 @@ impl Voice {
self.format().data_type
}
/// Returns the minimum number of samples that should be put in a buffer before it is
/// processable by the audio output.
///
/// If you put less than this value in the buffer, the buffer will not be processed and you
/// risk an underrun.
#[inline]
pub fn get_period(&self) -> usize {
self.voice.get_period()
}
/// Adds some PCM data to the voice's buffer.
///
/// This function indirectly returns a `Buffer` object that must be filled with the audio data.
/// The size of the buffer being returned depends on the current state of the backend
/// and can't be known in advance. However it is never greater than `max_samples`.
///
/// You must fill the buffer *entirely*, so do not set `max_samples` to a value greater
/// than the amount of data available to you.
///
/// Channels are interleaved. For example if you have two channels, you must write
/// the first sample of the first channel, then the first sample of the second channel,
/// then the second sample of the first channel, then the second sample of the second
/// channel, etc.
///
/// ## Panic
///
/// Panics if `max_samples` is 0.
///
#[inline]
pub fn append_data(&mut self, max_samples: usize) -> UnknownTypeBuffer {
assert!(max_samples != 0);
match self.get_samples_format() {
SampleFormat::U16 => UnknownTypeBuffer::U16(Buffer {
target: Some(self.voice.append_data(max_samples))
}),
SampleFormat::I16 => UnknownTypeBuffer::I16(Buffer {
target: Some(self.voice.append_data(max_samples))
}),
SampleFormat::F32 => UnknownTypeBuffer::F32(Buffer {
target: Some(self.voice.append_data(max_samples))
}),
}
}
/// Sends a command to the audio device that it should start playing.
///
/// Has no effect is the voice was already playing.
@ -389,25 +370,26 @@ impl Voice {
pub fn pause(&mut self) {
self.voice.pause()
}
}
pub struct SamplesStream(cpal_impl::SamplesStream);
impl Stream for SamplesStream {
type Item = UnknownTypeBuffer;
type Error = ();
/// Returns the number of samples in the buffer that are currently being processed by the
/// audio playback backend.
///
/// This function is useful to determine how much time it will take to finish playing the
/// current sound.
#[inline]
pub fn get_pending_samples(&self) -> usize {
self.voice.get_pending_samples()
fn poll(&mut self, task: &mut Task) -> Poll<Option<Self::Item>, Self::Error> {
self.0.poll(task)
}
/// Returns true if the voice has finished reading all the data you sent to it.
#[inline]
pub fn underflowed(&self) -> bool {
self.voice.underflowed()
fn schedule(&mut self, task: &mut Task) {
self.0.schedule(task)
}
}
impl<'a, T> Deref for Buffer<'a, T> where T: Sample {
impl<T> Deref for Buffer<T> where T: Sample {
type Target = [T];
#[inline]
@ -416,14 +398,14 @@ impl<'a, T> Deref for Buffer<'a, T> where T: Sample {
}
}
impl<'a, T> DerefMut for Buffer<'a, T> where T: Sample {
impl<T> DerefMut for Buffer<T> where T: Sample {
#[inline]
fn deref_mut(&mut self) -> &mut [T] {
self.target.as_mut().unwrap().get_buffer()
}
}
impl<'a, T> Drop for Buffer<'a, T> where T: Sample {
impl<T> Drop for Buffer<T> where T: Sample {
#[inline]
fn drop(&mut self) {
self.target.take().unwrap().finish();

3
src/wasapi/mod.rs
View File

@ -1,5 +1,6 @@
extern crate winapi;
extern crate ole32;
extern crate kernel32;
use std::io::Error as IoError;
use std::os::windows::ffi::OsStringExt;
@ -17,7 +18,7 @@ use SampleFormat;
pub use std::option::IntoIter as OptionIntoIter;
pub use self::enumerate::{EndpointsIterator, get_default_endpoint};
pub use self::voice::{Voice, Buffer};
pub use self::voice::{Voice, Buffer, EventLoop, SamplesStream};
pub type SupportedFormatsIterator = OptionIntoIter<Format>;

352
src/wasapi/voice.rs
View File

@ -1,4 +1,5 @@
use super::com;
use super::kernel32;
use super::ole32;
use super::winapi;
use super::Endpoint;
@ -9,25 +10,141 @@ use std::slice;
use std::mem;
use std::ptr;
use std::marker::PhantomData;
use std::sync::atomic::AtomicBool;
use std::sync::atomic::Ordering;
use std::sync::Arc;
use std::sync::Mutex;
use futures::Poll;
use futures::Task;
use futures::TaskHandle;
use futures::stream::Stream;
use CreationError;
use ChannelPosition;
use Format;
use SampleFormat;
use UnknownTypeBuffer;
pub struct EventLoop {
inner: Arc<EventLoopInner>,
}
unsafe impl Send for EventLoop {}
unsafe impl Sync for EventLoop {}
struct EventLoopInner {
// This event is signalled after elements have been added to `pending_scheduled`.
pending_scheduled_event: winapi::HANDLE,
scheduled: Mutex<EventLoopScheduled>,
pending_scheduled: Mutex<EventLoopScheduled>,
}
struct EventLoopScheduled {
// List of handles that correspond to voices.
// They are linked to `task_handles`, but we store them separately in order to easily call
// `WaitForMultipleObjectsEx` on the array without having to perform any conversion.
handles: Vec<winapi::HANDLE>,
// List of task handles corresponding to `handles`.
task_handles: Vec<(TaskHandle, Arc<AtomicBool>)>,
}
impl EventLoop {
pub fn new() -> EventLoop {
let pending_scheduled_event = unsafe {
kernel32::CreateEventA(ptr::null_mut(), 0, 0, ptr::null())
};
EventLoop {
inner: Arc::new(EventLoopInner {
pending_scheduled_event: pending_scheduled_event,
scheduled: Mutex::new(EventLoopScheduled {
handles: vec![pending_scheduled_event],
task_handles: vec![],
}),
pending_scheduled: Mutex::new(EventLoopScheduled {
handles: vec![],
task_handles: vec![],
})
})
}
}
pub fn run(&self) {
unsafe {
let mut scheduled = self.inner.scheduled.lock().unwrap();
loop {
// Creating a voice checks for the MAXIMUM_WAIT_OBJECTS limit.
debug_assert!(scheduled.handles.len() <= winapi::MAXIMUM_WAIT_OBJECTS as usize);
// Wait for any of the handles to be signalled, which means that the corresponding
// sound needs a buffer.
let result = kernel32::WaitForMultipleObjectsEx(scheduled.handles.len() as u32,
scheduled.handles.as_ptr(),
winapi::FALSE, winapi::INFINITE, /* TODO: allow setting a timeout */
winapi::FALSE /* irrelevant parameter here */);
// Notifying the corresponding task handler.
assert!(result >= winapi::WAIT_OBJECT_0);
let handle_id = (result - winapi::WAIT_OBJECT_0) as usize;
if handle_id == 0 {
let mut pending = self.inner.pending_scheduled.lock().unwrap();
scheduled.handles.append(&mut pending.handles);
scheduled.task_handles.append(&mut pending.task_handles);
} else {
scheduled.handles.remove(handle_id);
let (task_handle, ready) = scheduled.task_handles.remove(handle_id - 1);
ready.store(true, Ordering::Relaxed);
task_handle.notify();
}
}
}
}
}
impl Drop for EventLoop {
#[inline]
fn drop(&mut self) {
unsafe {
kernel32::CloseHandle(self.inner.pending_scheduled_event);
}
}
}
pub struct Voice {
audio_client: *mut winapi::IAudioClient,
render_client: *mut winapi::IAudioRenderClient,
inner: Arc<Mutex<VoiceInner>>,
playing: bool,
}
pub struct SamplesStream {
event_loop: Arc<EventLoopInner>,
inner: Arc<Mutex<VoiceInner>>,
// The event that is signalled whenever a buffer is ready to be submitted to the voice.
event: winapi::HANDLE, // TODO: not deleted
max_frames_in_buffer: winapi::UINT32,
bytes_per_frame: winapi::WORD,
playing: bool,
ready: Arc<AtomicBool>,
}
unsafe impl Send for SamplesStream {}
unsafe impl Sync for SamplesStream {}
struct VoiceInner {
audio_client: *mut winapi::IAudioClient,
render_client: *mut winapi::IAudioRenderClient,
}
unsafe impl Send for Voice {}
unsafe impl Sync for Voice {}
impl Voice {
pub fn new(end_point: &Endpoint, format: &Format) -> Result<Voice, CreationError> {
pub fn new(end_point: &Endpoint, format: &Format, event_loop: &EventLoop)
-> Result<(Voice, SamplesStream), CreationError>
{
unsafe {
// making sure that COM is initialized
// it's not actually sure that this is required, but when in doubt do it
@ -76,8 +193,9 @@ impl Voice {
};
// finally initializing the audio client
let hresult = (*audio_client).Initialize(share_mode, 0, 10000000, 0,
&format_attempt.Format, ptr::null());
let hresult = (*audio_client).Initialize(share_mode,
winapi::AUDCLNT_STREAMFLAGS_EVENTCALLBACK,
0, 0, &format_attempt.Format, ptr::null());
match check_result(hresult) {
Err(ref e) if e.raw_os_error() == Some(winapi::AUDCLNT_E_DEVICE_INVALIDATED) =>
{
@ -94,6 +212,25 @@ impl Voice {
format_attempt.Format
};
// Creating the event that will be signalled whenever we need to submit some samples.
let event = {
let event = kernel32::CreateEventA(ptr::null_mut(), 0, 0, ptr::null());
if event == ptr::null_mut() {
(*audio_client).Release();
panic!("Failed to create event");
}
match check_result((*audio_client).SetEventHandle(event)) {
Err(e) => {
(*audio_client).Release();
panic!("Failed to call SetEventHandle")
},
Ok(_) => ()
};
event
};
// obtaining the size of the samples buffer in number of frames
let max_frames_in_buffer = {
let mut max_frames_in_buffer = mem::uninitialized();
@ -115,7 +252,7 @@ impl Voice {
max_frames_in_buffer
};
// building a `IAudioRenderClient` that will be used to fill the samples buffer
// Building a `IAudioRenderClient` that will be used to fill the samples buffer.
let render_client = {
let mut render_client: *mut winapi::IAudioRenderClient = mem::uninitialized();
let hresult = (*audio_client).GetService(&winapi::IID_IAudioRenderClient,
@ -139,79 +276,37 @@ impl Voice {
&mut *render_client
};
// everything went fine
Ok(Voice {
// Everything went fine.
let inner = Arc::new(Mutex::new(VoiceInner {
audio_client: audio_client,
render_client: render_client,
}));
let voice = Voice {
inner: inner.clone(),
playing: false,
};
let samples_stream = SamplesStream {
event_loop: event_loop.inner.clone(),
inner: inner,
event: event,
max_frames_in_buffer: max_frames_in_buffer,
bytes_per_frame: format.nBlockAlign,
playing: false,
})
}
}
pub fn append_data<'a, T>(&'a mut self, max_elements: usize) -> Buffer<'a, T> {
unsafe {
// obtaining the number of frames that are available to be written
let frames_available = {
let mut padding = mem::uninitialized();
let hresult = (*self.audio_client).GetCurrentPadding(&mut padding);
check_result(hresult).unwrap();
self.max_frames_in_buffer - padding
ready: Arc::new(AtomicBool::new(false)),
};
// making sure `frames_available` is inferior to `max_elements`
let frames_available = cmp::min(frames_available,
max_elements as u32 * mem::size_of::<T>() as u32 /
self.bytes_per_frame as u32);
// the WASAPI has some weird behaviors when the buffer size is zero, so we handle this
// ourselves
if frames_available == 0 {
return Buffer::Empty;
}
// obtaining a pointer to the buffer
let (buffer_data, buffer_len) = {
let mut buffer: *mut winapi::BYTE = mem::uninitialized();
let hresult = (*self.render_client).GetBuffer(frames_available,
&mut buffer as *mut *mut _);
check_result(hresult).unwrap(); // FIXME: can return `AUDCLNT_E_DEVICE_INVALIDATED`
debug_assert!(!buffer.is_null());
(buffer as *mut T,
frames_available as usize * self.bytes_per_frame as usize / mem::size_of::<T>())
};
Buffer::Buffer {
render_client: self.render_client,
buffer_data: buffer_data,
buffer_len: buffer_len,
frames: frames_available,
marker: PhantomData,
}
}
}
#[inline]
pub fn get_period(&self) -> usize {
0
}
pub fn get_pending_samples(&self) -> usize {
unsafe {
let mut padding = mem::uninitialized();
let hresult = (*self.audio_client).GetCurrentPadding(&mut padding);
check_result(hresult).unwrap();
padding as usize
Ok((voice, samples_stream))
}
}
#[inline]
pub fn play(&mut self) {
if !self.playing {
let mut inner = self.inner.lock().unwrap();
unsafe {
let hresult = (*self.audio_client).Start();
let hresult = (*inner.audio_client).Start();
check_result(hresult).unwrap();
}
}
@ -222,27 +317,82 @@ impl Voice {
#[inline]
pub fn pause(&mut self) {
if self.playing {
let mut inner = self.inner.lock().unwrap();
unsafe {
let hresult = (*self.audio_client).Stop();
let hresult = (*inner.audio_client).Stop();
check_result(hresult).unwrap();
}
}
self.playing = false;
}
}
pub fn underflowed(&self) -> bool {
impl Stream for SamplesStream {
type Item = UnknownTypeBuffer;
type Error = ();
fn poll(&mut self, task: &mut Task) -> Poll<Option<Self::Item>, Self::Error> {
unsafe {
let mut padding = mem::uninitialized();
let hresult = (*self.audio_client).GetCurrentPadding(&mut padding);
check_result(hresult).unwrap();
padding == 0
if self.ready.swap(false, Ordering::Relaxed) == false {
let result = kernel32::WaitForSingleObject(self.event, 0);
// Returning if timeout.
match result {
winapi::WAIT_OBJECT_0 => (),
winapi::WAIT_TIMEOUT => return Poll::NotReady,
_ => unreachable!()
};
}
let mut inner = self.inner.lock().unwrap();
// Obtaining the number of frames that are available to be written.
let frames_available = {
let mut padding = mem::uninitialized();
let hresult = (*inner.audio_client).GetCurrentPadding(&mut padding);
check_result(hresult).unwrap();
self.max_frames_in_buffer - padding
};
assert!(frames_available >= 0);
// Obtaining a pointer to the buffer.
let (buffer_data, buffer_len) = {
let mut buffer: *mut winapi::BYTE = mem::uninitialized();
let hresult = (*inner.render_client).GetBuffer(frames_available,
&mut buffer as *mut *mut _);
check_result(hresult).unwrap(); // FIXME: can return `AUDCLNT_E_DEVICE_INVALIDATED`
debug_assert!(!buffer.is_null());
(buffer as *mut _,
frames_available as usize * self.bytes_per_frame as usize / mem::size_of::<f32>()) // FIXME: correct size
};
let buffer = Buffer {
voice: self.inner.clone(),
buffer_data: buffer_data,
buffer_len: buffer_len,
frames: frames_available,
};
Poll::Ok(Some(UnknownTypeBuffer::F32(::Buffer { target: Some(buffer) }))) // FIXME: not necessarily F32
}
}
fn schedule(&mut self, task: &mut Task) {
let mut pending = self.event_loop.pending_scheduled.lock().unwrap();
pending.handles.push(self.event);
pending.task_handles.push((task.handle().clone(), self.ready.clone()));
drop(pending);
let result = unsafe { kernel32::SetEvent(self.event_loop.pending_scheduled_event) };
assert!(result != 0);
}
}
impl Drop for Voice {
impl Drop for VoiceInner {
#[inline]
fn drop(&mut self) {
unsafe {
@ -252,48 +402,40 @@ impl Drop for Voice {
}
}
pub enum Buffer<'a, T: 'a> {
Empty,
Buffer {
render_client: *mut winapi::IAudioRenderClient,
buffer_data: *mut T,
buffer_len: usize,
frames: winapi::UINT32,
marker: PhantomData<&'a mut T>,
},
pub struct Buffer<T> {
voice: Arc<Mutex<VoiceInner>>,
buffer_data: *mut T,
buffer_len: usize,
frames: winapi::UINT32,
}
impl<'a, T> Buffer<'a, T> {
unsafe impl<T> Send for Buffer<T> {}
impl<T> Buffer<T> {
#[inline]
pub fn get_buffer<'b>(&'b mut self) -> &'b mut [T] {
match self {
&mut Buffer::Empty => &mut [],
&mut Buffer::Buffer { buffer_data, buffer_len, .. } => unsafe {
slice::from_raw_parts_mut(buffer_data, buffer_len)
},
pub fn get_buffer(&mut self) -> &mut [T] {
unsafe {
slice::from_raw_parts_mut(self.buffer_data, self.buffer_len)
}
}
#[inline]
pub fn len(&self) -> usize {
match self {
&Buffer::Empty => 0,
&Buffer::Buffer { buffer_len, .. } => buffer_len,
}
self.buffer_len
}
#[inline]
pub fn finish(self) {
if let Buffer::Buffer { render_client, frames, .. } = self {
unsafe {
let hresult = (*render_client).ReleaseBuffer(frames as u32, 0);
match check_result(hresult) {
// ignoring the error that is produced if the device has been disconnected
Err(ref e)
if e.raw_os_error() == Some(winapi::AUDCLNT_E_DEVICE_INVALIDATED) => (),
e => e.unwrap(),
};
}
unsafe {
let mut inner = self.voice.lock().unwrap();
let hresult = (*inner.render_client).ReleaseBuffer(self.frames as u32, 0);
match check_result(hresult) {
// ignoring the error that is produced if the device has been disconnected
Err(ref e)
if e.raw_os_error() == Some(winapi::AUDCLNT_E_DEVICE_INVALIDATED) => (),
e => e.unwrap(),
};
}
}
}