1018 lines
39 KiB
Rust
1018 lines
39 KiB
Rust
extern crate alsa_sys as alsa;
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extern crate libc;
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pub use self::enumerate::{Devices, default_input_device, default_output_device};
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use ChannelCount;
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use BackendSpecificError;
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use BuildStreamError;
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use DefaultFormatError;
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use DeviceNameError;
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use Format;
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use PauseStreamError;
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use PlayStreamError;
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use SupportedFormatsError;
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use SampleFormat;
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use SampleRate;
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use StreamData;
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use SupportedFormat;
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use UnknownTypeInputBuffer;
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use UnknownTypeOutputBuffer;
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use std::{cmp, ffi, mem, ptr};
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use std::sync::Mutex;
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use std::sync::mpsc::{channel, Sender, Receiver};
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use std::sync::atomic::{AtomicUsize, Ordering};
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use std::vec::IntoIter as VecIntoIter;
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pub type SupportedInputFormats = VecIntoIter<SupportedFormat>;
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pub type SupportedOutputFormats = VecIntoIter<SupportedFormat>;
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mod enumerate;
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struct Trigger {
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// [read fd, write fd]
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fds: [libc::c_int; 2],
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}
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impl Trigger {
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fn new() -> Self {
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let mut fds = [0, 0];
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match unsafe { libc::pipe(fds.as_mut_ptr()) } {
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0 => Trigger { fds: fds },
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_ => panic!("Could not create pipe"),
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}
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}
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fn read_fd(&self) -> libc::c_int {
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self.fds[0]
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}
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fn write_fd(&self) -> libc::c_int {
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self.fds[1]
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}
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fn wakeup(&self) {
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let buf = 1u64;
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let ret = unsafe { libc::write(self.write_fd(), &buf as *const u64 as *const _, 8) };
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assert!(ret == 8);
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}
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fn clear_pipe(&self) {
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let mut out = 0u64;
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let ret = unsafe { libc::read(self.read_fd(), &mut out as *mut u64 as *mut _, 8) };
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assert_eq!(ret, 8);
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}
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}
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impl Drop for Trigger {
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fn drop(&mut self) {
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unsafe {
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libc::close(self.fds[0]);
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libc::close(self.fds[1]);
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}
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}
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}
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#[derive(Clone, Debug, PartialEq, Eq)]
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pub struct Device(String);
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impl Device {
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#[inline]
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pub fn name(&self) -> Result<String, DeviceNameError> {
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Ok(self.0.clone())
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}
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unsafe fn supported_formats(
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&self,
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stream_t: alsa::snd_pcm_stream_t,
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) -> Result<VecIntoIter<SupportedFormat>, SupportedFormatsError>
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{
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let mut handle = mem::uninitialized();
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let device_name = match ffi::CString::new(&self.0[..]) {
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Ok(name) => name,
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Err(err) => {
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let description = format!("failed to retrieve device name: {}", err);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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};
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match alsa::snd_pcm_open(
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&mut handle,
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device_name.as_ptr() as *const _,
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stream_t,
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alsa::SND_PCM_NONBLOCK,
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) {
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-2 |
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-16 /* determined empirically */ => return Err(SupportedFormatsError::DeviceNotAvailable),
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-22 => return Err(SupportedFormatsError::InvalidArgument),
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e => if let Err(description) = check_errors(e) {
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let err = BackendSpecificError { description };
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return Err(err.into())
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}
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}
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let hw_params = HwParams::alloc();
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match check_errors(alsa::snd_pcm_hw_params_any(handle, hw_params.0)) {
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Err(description) => {
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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Ok(_) => (),
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};
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// TODO: check endianess
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const FORMATS: [(SampleFormat, alsa::snd_pcm_format_t); 3] =
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[
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//SND_PCM_FORMAT_S8,
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//SND_PCM_FORMAT_U8,
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(SampleFormat::I16, alsa::SND_PCM_FORMAT_S16_LE),
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//SND_PCM_FORMAT_S16_BE,
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(SampleFormat::U16, alsa::SND_PCM_FORMAT_U16_LE),
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//SND_PCM_FORMAT_U16_BE,
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/*SND_PCM_FORMAT_S24_LE,
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SND_PCM_FORMAT_S24_BE,
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SND_PCM_FORMAT_U24_LE,
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SND_PCM_FORMAT_U24_BE,
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SND_PCM_FORMAT_S32_LE,
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SND_PCM_FORMAT_S32_BE,
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SND_PCM_FORMAT_U32_LE,
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SND_PCM_FORMAT_U32_BE,*/
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(SampleFormat::F32, alsa::SND_PCM_FORMAT_FLOAT_LE) /*SND_PCM_FORMAT_FLOAT_BE,
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SND_PCM_FORMAT_FLOAT64_LE,
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SND_PCM_FORMAT_FLOAT64_BE,
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SND_PCM_FORMAT_IEC958_SUBFRAME_LE,
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SND_PCM_FORMAT_IEC958_SUBFRAME_BE,
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SND_PCM_FORMAT_MU_LAW,
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SND_PCM_FORMAT_A_LAW,
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SND_PCM_FORMAT_IMA_ADPCM,
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SND_PCM_FORMAT_MPEG,
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SND_PCM_FORMAT_GSM,
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SND_PCM_FORMAT_SPECIAL,
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SND_PCM_FORMAT_S24_3LE,
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SND_PCM_FORMAT_S24_3BE,
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SND_PCM_FORMAT_U24_3LE,
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SND_PCM_FORMAT_U24_3BE,
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SND_PCM_FORMAT_S20_3LE,
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SND_PCM_FORMAT_S20_3BE,
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SND_PCM_FORMAT_U20_3LE,
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SND_PCM_FORMAT_U20_3BE,
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SND_PCM_FORMAT_S18_3LE,
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SND_PCM_FORMAT_S18_3BE,
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SND_PCM_FORMAT_U18_3LE,
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SND_PCM_FORMAT_U18_3BE,*/,
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];
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let mut supported_formats = Vec::new();
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for &(sample_format, alsa_format) in FORMATS.iter() {
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if alsa::snd_pcm_hw_params_test_format(handle,
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hw_params.0,
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alsa_format) == 0
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{
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supported_formats.push(sample_format);
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}
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}
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let mut min_rate = mem::uninitialized();
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if let Err(desc) = check_errors(alsa::snd_pcm_hw_params_get_rate_min(
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hw_params.0,
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&mut min_rate,
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ptr::null_mut(),
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)) {
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let description = format!("unable to get minimum supported rate: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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let mut max_rate = mem::uninitialized();
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if let Err(desc) = check_errors(alsa::snd_pcm_hw_params_get_rate_max(
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hw_params.0,
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&mut max_rate,
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ptr::null_mut(),
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)) {
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let description = format!("unable to get maximum supported rate: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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let sample_rates = if min_rate == max_rate {
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vec![(min_rate, max_rate)]
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} else if alsa::snd_pcm_hw_params_test_rate(handle,
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hw_params.0,
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min_rate + 1,
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0) == 0
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{
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vec![(min_rate, max_rate)]
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} else {
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const RATES: [libc::c_uint; 13] = [
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5512,
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8000,
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11025,
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16000,
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22050,
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32000,
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44100,
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48000,
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64000,
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88200,
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96000,
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176400,
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192000,
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];
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let mut rates = Vec::new();
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for &rate in RATES.iter() {
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if alsa::snd_pcm_hw_params_test_rate(handle,
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hw_params.0,
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rate,
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0) == 0
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{
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rates.push((rate, rate));
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}
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}
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if rates.len() == 0 {
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vec![(min_rate, max_rate)]
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} else {
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rates
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}
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};
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let mut min_channels = mem::uninitialized();
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if let Err(desc) = check_errors(alsa::snd_pcm_hw_params_get_channels_min(hw_params.0, &mut min_channels)) {
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let description = format!("unable to get minimum supported channel count: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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let mut max_channels = mem::uninitialized();
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if let Err(desc) = check_errors(alsa::snd_pcm_hw_params_get_channels_max(hw_params.0, &mut max_channels)) {
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let description = format!("unable to get maximum supported channel count: {}", desc);
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let err = BackendSpecificError { description };
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return Err(err.into());
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}
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let max_channels = cmp::min(max_channels, 32); // TODO: limiting to 32 channels or too much stuff is returned
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let supported_channels = (min_channels .. max_channels + 1)
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.filter_map(|num| if alsa::snd_pcm_hw_params_test_channels(
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handle,
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hw_params.0,
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num,
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) == 0
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{
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Some(num as ChannelCount)
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} else {
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None
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})
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.collect::<Vec<_>>();
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let mut output = Vec::with_capacity(supported_formats.len() * supported_channels.len() *
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sample_rates.len());
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for &data_type in supported_formats.iter() {
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for channels in supported_channels.iter() {
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for &(min_rate, max_rate) in sample_rates.iter() {
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output.push(SupportedFormat {
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channels: channels.clone(),
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min_sample_rate: SampleRate(min_rate as u32),
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max_sample_rate: SampleRate(max_rate as u32),
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data_type: data_type,
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});
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}
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}
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}
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// TODO: RAII
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alsa::snd_pcm_close(handle);
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Ok(output.into_iter())
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}
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pub fn supported_input_formats(&self) -> Result<SupportedInputFormats, SupportedFormatsError> {
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unsafe {
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self.supported_formats(alsa::SND_PCM_STREAM_CAPTURE)
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}
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}
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pub fn supported_output_formats(&self) -> Result<SupportedOutputFormats, SupportedFormatsError> {
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unsafe {
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self.supported_formats(alsa::SND_PCM_STREAM_PLAYBACK)
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}
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}
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// ALSA does not offer default stream formats, so instead we compare all supported formats by
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// the `SupportedFormat::cmp_default_heuristics` order and select the greatest.
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fn default_format(
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&self,
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stream_t: alsa::snd_pcm_stream_t,
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) -> Result<Format, DefaultFormatError>
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{
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let mut formats: Vec<_> = unsafe {
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match self.supported_formats(stream_t) {
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Err(SupportedFormatsError::DeviceNotAvailable) => {
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return Err(DefaultFormatError::DeviceNotAvailable);
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},
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Err(SupportedFormatsError::InvalidArgument) => {
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// this happens sometimes when querying for input and output capabilities but
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// the device supports only one
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return Err(DefaultFormatError::StreamTypeNotSupported);
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}
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Err(SupportedFormatsError::BackendSpecific { err }) => {
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return Err(err.into());
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}
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Ok(fmts) => fmts.collect(),
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}
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};
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formats.sort_by(|a, b| a.cmp_default_heuristics(b));
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match formats.into_iter().last() {
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Some(f) => {
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let min_r = f.min_sample_rate;
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let max_r = f.max_sample_rate;
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let mut format = f.with_max_sample_rate();
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const HZ_44100: SampleRate = SampleRate(44_100);
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if min_r <= HZ_44100 && HZ_44100 <= max_r {
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format.sample_rate = HZ_44100;
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}
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Ok(format)
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},
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None => Err(DefaultFormatError::StreamTypeNotSupported)
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}
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}
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pub fn default_input_format(&self) -> Result<Format, DefaultFormatError> {
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self.default_format(alsa::SND_PCM_STREAM_CAPTURE)
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}
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pub fn default_output_format(&self) -> Result<Format, DefaultFormatError> {
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self.default_format(alsa::SND_PCM_STREAM_PLAYBACK)
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}
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}
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pub struct EventLoop {
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// Each newly-created stream gets a new ID from this counter. The counter is then incremented.
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next_stream_id: AtomicUsize, // TODO: use AtomicU64 when stable?
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// A trigger that uses a `pipe()` as backend. Signalled whenever a new command is ready, so
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// that `poll()` can wake up and pick the changes.
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pending_trigger: Trigger,
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// This field is locked by the `run()` method.
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// The mutex also ensures that only one thread at a time has `run()` running.
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run_context: Mutex<RunContext>,
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// Commands processed by the `run()` method that is currently running.
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commands: Sender<Command>,
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}
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unsafe impl Send for EventLoop {
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}
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unsafe impl Sync for EventLoop {
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}
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enum Command {
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NewStream(StreamInner),
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PlayStream(StreamId),
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PauseStream(StreamId),
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DestroyStream(StreamId),
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}
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struct RunContext {
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// Descriptors to wait for. Always contains `pending_trigger.read_fd()` as first element.
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descriptors: Vec<libc::pollfd>,
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// List of streams that are written in `descriptors`.
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streams: Vec<StreamInner>,
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commands: Receiver<Command>,
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}
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struct StreamInner {
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// The id of the stream.
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id: StreamId,
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// The ALSA channel.
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channel: *mut alsa::snd_pcm_t,
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// When converting between file descriptors and `snd_pcm_t`, this is the number of
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// file descriptors that this `snd_pcm_t` uses.
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num_descriptors: usize,
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// Format of the samples.
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sample_format: SampleFormat,
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// Number of channels, ie. number of samples per frame.
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num_channels: u16,
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// Number of samples that can fit in the buffer.
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buffer_len: usize,
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// Minimum number of samples to put in the buffer.
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period_len: usize,
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// Whether or not the hardware supports pausing the stream.
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can_pause: bool,
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// Whether or not the sample stream is currently paused.
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is_paused: bool,
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// A file descriptor opened with `eventfd`.
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// It is used to wait for resume signal.
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resume_trigger: Trigger,
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// Lazily allocated buffer that is reused inside the loop.
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// Zero-allocate a new buffer (the fastest way to have zeroed memory) at the first time this is
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// used.
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buffer: Option<Vec<u8>>,
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}
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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pub struct StreamId(usize);
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impl EventLoop {
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#[inline]
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pub fn new() -> EventLoop {
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let pending_trigger = Trigger::new();
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let initial_descriptors = vec![
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libc::pollfd {
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fd: pending_trigger.read_fd(),
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events: libc::POLLIN,
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revents: 0,
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},
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];
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let (tx, rx) = channel();
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let run_context = Mutex::new(RunContext {
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descriptors: initial_descriptors,
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streams: Vec::new(),
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commands: rx,
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});
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EventLoop {
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next_stream_id: AtomicUsize::new(0),
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pending_trigger: pending_trigger,
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run_context,
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commands: tx,
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}
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}
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#[inline]
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pub fn run<F>(&self, mut callback: F) -> !
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where F: FnMut(StreamId, StreamData)
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{
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self.run_inner(&mut callback)
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}
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fn run_inner(&self, callback: &mut FnMut(StreamId, StreamData)) -> ! {
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unsafe {
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let mut run_context = self.run_context.lock().unwrap();
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let run_context = &mut *run_context;
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loop {
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{
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for command in run_context.commands.try_iter() {
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match command {
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Command::DestroyStream(stream_id) => {
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run_context.streams.retain(|s| s.id != stream_id);
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},
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Command::PlayStream(stream_id) => {
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if let Some(stream) = run_context.streams.iter_mut()
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.find(|stream| stream.can_pause && stream.id == stream_id)
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{
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alsa::snd_pcm_pause(stream.channel, 0);
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stream.is_paused = false;
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}
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},
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Command::PauseStream(stream_id) => {
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if let Some(stream) = run_context.streams.iter_mut()
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.find(|stream| stream.can_pause && stream.id == stream_id)
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{
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alsa::snd_pcm_pause(stream.channel, 1);
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stream.is_paused = true;
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}
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},
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Command::NewStream(stream_inner) => {
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run_context.streams.push(stream_inner);
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},
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}
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}
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run_context.descriptors = vec![
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libc::pollfd {
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fd: self.pending_trigger.read_fd(),
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events: libc::POLLIN,
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revents: 0,
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},
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];
|
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for stream in run_context.streams.iter() {
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run_context.descriptors.reserve(stream.num_descriptors);
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let len = run_context.descriptors.len();
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let filled = alsa::snd_pcm_poll_descriptors(stream.channel,
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run_context
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.descriptors
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.as_mut_ptr()
|
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.offset(len as isize),
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stream.num_descriptors as
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libc::c_uint);
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debug_assert_eq!(filled, stream.num_descriptors as libc::c_int);
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run_context.descriptors.set_len(len + stream.num_descriptors);
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}
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}
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let ret = libc::poll(run_context.descriptors.as_mut_ptr(),
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run_context.descriptors.len() as libc::nfds_t,
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-1 /* infinite */);
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assert!(ret >= 0, "poll() failed");
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|
|
|
if ret == 0 {
|
|
continue;
|
|
}
|
|
|
|
// If the `pending_trigger` was signaled, we need to process the comands.
|
|
if run_context.descriptors[0].revents != 0 {
|
|
run_context.descriptors[0].revents = 0;
|
|
self.pending_trigger.clear_pipe();
|
|
}
|
|
|
|
// 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() {
|
|
enum StreamType { Input, Output }
|
|
let stream_type;
|
|
let stream_inner = run_context.streams.get_mut(i_stream).unwrap();
|
|
|
|
// Check whether the event is `POLLOUT` or `POLLIN`. If neither, `continue`.
|
|
{
|
|
let mut revent = mem::uninitialized();
|
|
|
|
{
|
|
let num_descriptors = stream_inner.num_descriptors as libc::c_uint;
|
|
let desc_ptr =
|
|
run_context.descriptors.as_mut_ptr().offset(i_descriptor);
|
|
let res = alsa::snd_pcm_poll_descriptors_revents(stream_inner.channel,
|
|
desc_ptr,
|
|
num_descriptors,
|
|
&mut revent);
|
|
check_errors(res).unwrap();
|
|
}
|
|
|
|
if revent as i16 == libc::POLLOUT {
|
|
stream_type = StreamType::Output;
|
|
} else if revent as i16 == libc::POLLIN {
|
|
stream_type = StreamType::Input;
|
|
} else {
|
|
i_descriptor += stream_inner.num_descriptors as isize;
|
|
i_stream += 1;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Determine the number of samples that are available to read/write.
|
|
let available_samples = {
|
|
let available = alsa::snd_pcm_avail(stream_inner.channel); // TODO: what about snd_pcm_avail_update?
|
|
|
|
if available == -32 {
|
|
// buffer underrun
|
|
stream_inner.buffer_len
|
|
} else if available < 0 {
|
|
check_errors(available as libc::c_int)
|
|
.expect("buffer is not available");
|
|
unreachable!()
|
|
} else {
|
|
(available * stream_inner.num_channels as alsa::snd_pcm_sframes_t) as
|
|
usize
|
|
}
|
|
};
|
|
|
|
if available_samples < stream_inner.period_len {
|
|
i_descriptor += stream_inner.num_descriptors as isize;
|
|
i_stream += 1;
|
|
continue;
|
|
}
|
|
|
|
let stream_id = stream_inner.id.clone();
|
|
|
|
let available_frames = available_samples / stream_inner.num_channels as usize;
|
|
|
|
let buffer_size = stream_inner.sample_format.sample_size() * available_samples;
|
|
// Could be written with a match with improved borrow checking
|
|
if stream_inner.buffer.is_none() {
|
|
stream_inner.buffer = Some(vec![0u8; buffer_size]);
|
|
} else {
|
|
stream_inner.buffer.as_mut().unwrap().resize(buffer_size, 0u8);
|
|
}
|
|
let buffer = stream_inner.buffer.as_mut().unwrap();
|
|
|
|
match stream_type {
|
|
StreamType::Input => {
|
|
let err = alsa::snd_pcm_readi(
|
|
stream_inner.channel,
|
|
buffer.as_mut_ptr() as *mut _,
|
|
available_frames as alsa::snd_pcm_uframes_t,
|
|
);
|
|
check_errors(err as _).expect("snd_pcm_readi error");
|
|
|
|
let input_buffer = match stream_inner.sample_format {
|
|
SampleFormat::I16 => UnknownTypeInputBuffer::I16(::InputBuffer {
|
|
buffer: cast_input_buffer(buffer),
|
|
}),
|
|
SampleFormat::U16 => UnknownTypeInputBuffer::U16(::InputBuffer {
|
|
buffer: cast_input_buffer(buffer),
|
|
}),
|
|
SampleFormat::F32 => UnknownTypeInputBuffer::F32(::InputBuffer {
|
|
buffer: cast_input_buffer(buffer),
|
|
}),
|
|
};
|
|
let stream_data = StreamData::Input {
|
|
buffer: input_buffer,
|
|
};
|
|
callback(stream_id, stream_data);
|
|
},
|
|
StreamType::Output => {
|
|
{
|
|
// We're now sure that we're ready to write data.
|
|
let output_buffer = match stream_inner.sample_format {
|
|
SampleFormat::I16 => UnknownTypeOutputBuffer::I16(::OutputBuffer {
|
|
buffer: cast_output_buffer(buffer),
|
|
}),
|
|
SampleFormat::U16 => UnknownTypeOutputBuffer::U16(::OutputBuffer {
|
|
buffer: cast_output_buffer(buffer),
|
|
}),
|
|
SampleFormat::F32 => UnknownTypeOutputBuffer::F32(::OutputBuffer {
|
|
buffer: cast_output_buffer(buffer),
|
|
}),
|
|
};
|
|
|
|
let stream_data = StreamData::Output {
|
|
buffer: output_buffer,
|
|
};
|
|
callback(stream_id, stream_data);
|
|
}
|
|
loop {
|
|
let result = alsa::snd_pcm_writei(
|
|
stream_inner.channel,
|
|
buffer.as_ptr() as *const _,
|
|
available_frames as alsa::snd_pcm_uframes_t,
|
|
);
|
|
|
|
if result == -32 {
|
|
// buffer underrun
|
|
alsa::snd_pcm_prepare(stream_inner.channel);
|
|
} else if result < 0 {
|
|
check_errors(result as libc::c_int)
|
|
.expect("could not write pcm");
|
|
} else {
|
|
assert_eq!(result as usize, available_frames);
|
|
break;
|
|
}
|
|
}
|
|
},
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pub 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 = mem::uninitialized();
|
|
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() {
|
|
return Err(BuildStreamError::StreamIdOverflow);
|
|
}
|
|
|
|
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: None,
|
|
};
|
|
|
|
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)
|
|
}
|
|
}
|
|
|
|
pub 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 = mem::uninitialized();
|
|
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: None,
|
|
};
|
|
|
|
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_trigger.wakeup();
|
|
}
|
|
|
|
#[inline]
|
|
pub fn destroy_stream(&self, stream_id: StreamId) {
|
|
self.push_command(Command::DestroyStream(stream_id));
|
|
}
|
|
|
|
#[inline]
|
|
pub fn play_stream(&self, stream_id: StreamId) -> Result<(), PlayStreamError> {
|
|
self.push_command(Command::PlayStream(stream_id));
|
|
Ok(())
|
|
}
|
|
|
|
#[inline]
|
|
pub fn pause_stream(&self, stream_id: StreamId) -> Result<(), PauseStreamError> {
|
|
self.push_command(Command::PauseStream(stream_id));
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
unsafe fn set_hw_params_from_format(
|
|
pcm_handle: *mut alsa::snd_pcm_t,
|
|
hw_params: &HwParams,
|
|
format: &Format,
|
|
) -> Result<(), String> {
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_any(pcm_handle, hw_params.0)) {
|
|
return Err(format!("errors on pcm handle: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_access(pcm_handle,
|
|
hw_params.0,
|
|
alsa::SND_PCM_ACCESS_RW_INTERLEAVED)) {
|
|
return Err(format!("handle not acessible: {}", e));
|
|
}
|
|
|
|
let data_type = if cfg!(target_endian = "big") {
|
|
match format.data_type {
|
|
SampleFormat::I16 => alsa::SND_PCM_FORMAT_S16_BE,
|
|
SampleFormat::U16 => alsa::SND_PCM_FORMAT_U16_BE,
|
|
SampleFormat::F32 => alsa::SND_PCM_FORMAT_FLOAT_BE,
|
|
}
|
|
} else {
|
|
match format.data_type {
|
|
SampleFormat::I16 => alsa::SND_PCM_FORMAT_S16_LE,
|
|
SampleFormat::U16 => alsa::SND_PCM_FORMAT_U16_LE,
|
|
SampleFormat::F32 => alsa::SND_PCM_FORMAT_FLOAT_LE,
|
|
}
|
|
};
|
|
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_format(pcm_handle,
|
|
hw_params.0,
|
|
data_type)) {
|
|
return Err(format!("format could not be set: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_rate(pcm_handle,
|
|
hw_params.0,
|
|
format.sample_rate.0 as libc::c_uint,
|
|
0)) {
|
|
return Err(format!("sample rate could not be set: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_channels(pcm_handle,
|
|
hw_params.0,
|
|
format.channels as
|
|
libc::c_uint)) {
|
|
return Err(format!("channel count could not be set: {}", e));
|
|
}
|
|
|
|
// TODO: Review this. 200ms seems arbitrary...
|
|
let mut max_buffer_size = format.sample_rate.0 as alsa::snd_pcm_uframes_t /
|
|
format.channels as alsa::snd_pcm_uframes_t /
|
|
5; // 200ms of buffer
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params_set_buffer_size_max(pcm_handle,
|
|
hw_params.0,
|
|
&mut max_buffer_size))
|
|
{
|
|
return Err(format!("max buffer size could not be set: {}", e));
|
|
}
|
|
|
|
if let Err(e) = check_errors(alsa::snd_pcm_hw_params(pcm_handle, hw_params.0)) {
|
|
return Err(format!("hardware params could not be set: {}", e));
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
unsafe fn set_sw_params_from_format(
|
|
pcm_handle: *mut alsa::snd_pcm_t,
|
|
format: &Format,
|
|
) -> Result<(usize, usize), String>
|
|
{
|
|
let mut sw_params = mem::uninitialized(); // TODO: RAII
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params_malloc(&mut sw_params)) {
|
|
return Err(format!("snd_pcm_sw_params_malloc failed: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params_current(pcm_handle, sw_params)) {
|
|
return Err(format!("snd_pcm_sw_params_current failed: {}", e));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params_set_start_threshold(pcm_handle, sw_params, 0)) {
|
|
return Err(format!("snd_pcm_sw_params_set_start_threshold failed: {}", e));
|
|
}
|
|
|
|
let (buffer_len, period_len) = {
|
|
let mut buffer = mem::uninitialized();
|
|
let mut period = mem::uninitialized();
|
|
if let Err(e) = check_errors(alsa::snd_pcm_get_params(pcm_handle, &mut buffer, &mut period)) {
|
|
return Err(format!("failed to initialize buffer: {}", e));
|
|
}
|
|
if buffer == 0 {
|
|
return Err(format!("initialization resulted in a null buffer"));
|
|
}
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params_set_avail_min(pcm_handle, sw_params, period)) {
|
|
return Err(format!("snd_pcm_sw_params_set_avail_min failed: {}", e));
|
|
}
|
|
let buffer = buffer as usize * format.channels as usize;
|
|
let period = period as usize * format.channels as usize;
|
|
(buffer, period)
|
|
};
|
|
|
|
if let Err(e) = check_errors(alsa::snd_pcm_sw_params(pcm_handle, sw_params)) {
|
|
return Err(format!("snd_pcm_sw_params failed: {}", e));
|
|
}
|
|
|
|
alsa::snd_pcm_sw_params_free(sw_params);
|
|
Ok((buffer_len, period_len))
|
|
}
|
|
|
|
/// Wrapper around `hw_params`.
|
|
struct HwParams(*mut alsa::snd_pcm_hw_params_t);
|
|
|
|
impl HwParams {
|
|
pub fn alloc() -> HwParams {
|
|
unsafe {
|
|
let mut hw_params = mem::uninitialized();
|
|
check_errors(alsa::snd_pcm_hw_params_malloc(&mut hw_params))
|
|
.expect("unable to get hardware parameters");
|
|
HwParams(hw_params)
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Drop for HwParams {
|
|
fn drop(&mut self) {
|
|
unsafe {
|
|
alsa::snd_pcm_hw_params_free(self.0);
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Drop for StreamInner {
|
|
#[inline]
|
|
fn drop(&mut self) {
|
|
unsafe {
|
|
alsa::snd_pcm_close(self.channel);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
fn check_errors(err: libc::c_int) -> Result<(), String> {
|
|
if err < 0 {
|
|
unsafe {
|
|
let s = ffi::CStr::from_ptr(alsa::snd_strerror(err))
|
|
.to_bytes()
|
|
.to_vec();
|
|
let s = String::from_utf8(s).expect("Streaming error occured");
|
|
return Err(s);
|
|
}
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
|
|
/// Cast a byte slice into a (immutable) slice of desired type.
|
|
/// Safety: it's up to the caller to ensure that the input slice has valid bit representations.
|
|
unsafe fn cast_input_buffer<T>(v: &[u8]) -> &[T] {
|
|
debug_assert!(v.len() % std::mem::size_of::<T>() == 0);
|
|
std::slice::from_raw_parts(v.as_ptr() as *const T, v.len() / std::mem::size_of::<T>())
|
|
}
|
|
|
|
/// Cast a byte slice into a mutable slice of desired type.
|
|
/// Safety: it's up to the caller to ensure that the input slice has valid bit representations.
|
|
unsafe fn cast_output_buffer<T>(v: &mut [u8]) -> &mut [T] {
|
|
debug_assert!(v.len() % std::mem::size_of::<T>() == 0);
|
|
std::slice::from_raw_parts_mut(v.as_mut_ptr() as *mut T, v.len() / std::mem::size_of::<T>())
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}
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