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#![macro_use]
use libc::{c_void, c_int, c_char, free};
use std::{fmt, str};
use std::ffi::CStr;
use std::error::Error as StdError;
/// ALSA error
///
/// Most ALSA functions can return a negative error code.
/// If so, then that error code is wrapped into this `Error` struct.
/// An Error is also returned in case ALSA returns a string that
/// cannot be translated into Rust's UTF-8 strings.
#[derive(Debug, Clone, PartialEq, Copy)]
pub struct Error(&'static str, nix::Error);
pub type Result<T> = ::std::result::Result<T, Error>;
macro_rules! acheck {
($f: ident ( $($x: expr),* ) ) => {{
let r = unsafe { alsa::$f( $($x),* ) };
if r < 0 { Err(Error::new(stringify!($f), -r as ::libc::c_int)) }
else { Ok(r) }
}}
}
pub fn from_const<'a>(func: &'static str, s: *const c_char) -> Result<&'a str> {
if s.is_null() { return Err(invalid_str(func)) };
let cc = unsafe { CStr::from_ptr(s) };
str::from_utf8(cc.to_bytes()).map_err(|_| invalid_str(func))
}
pub fn from_alloc(func: &'static str, s: *mut c_char) -> Result<String> {
if s.is_null() { return Err(invalid_str(func)) };
let c = unsafe { CStr::from_ptr(s) };
let ss = str::from_utf8(c.to_bytes()).map_err(|_| {
unsafe { free(s as *mut c_void); }
invalid_str(func)
})?.to_string();
unsafe { free(s as *mut c_void); }
Ok(ss)
}
pub fn from_code(func: &'static str, r: c_int) -> Result<c_int> {
if r < 0 { Err(Error::new(func, r)) }
else { Ok(r) }
}
impl Error {
pub fn new(func: &'static str, res: c_int) -> Error {
let errno = nix::errno::Errno::from_i32(res as i32);
Error(func, errno)
}
pub fn unsupported(func: &'static str) -> Error {
Error(func, nix::Error::ENOTSUP)
}
/// The function which failed.
pub fn func(&self) -> &'static str { self.0 }
/// Underlying error
///
/// Match this against the re-export of `nix::Error` in this crate, not against a specific version
/// of the nix crate. The nix crate version might be updated with minor updates of this library.
pub fn errno(&self) -> nix::Error { self.1 }
/// Underlying error
///
/// Match this against the re-export of `nix::Error` in this crate, not against a specific version
/// of the nix crate. The nix crate version might be updated with minor updates of this library.
pub fn nix_error(&self) -> nix::Error { self.1 }
}
pub fn invalid_str(func: &'static str) -> Error { Error(func, nix::Error::EILSEQ) }
impl StdError for Error {
fn source(&self) -> Option<&(dyn StdError + 'static)> { Some(&self.1) }
fn description(&self) -> &str { "ALSA error" }
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "ALSA function '{}' failed with error '{}'", self.0, self.1)
}
}
impl From<Error> for fmt::Error {
fn from(_: Error) -> fmt::Error { fmt::Error }
}
#[test]
fn broken_pcm_name() {
use std::ffi::CString;
let e = crate::PCM::open(&*CString::new("this_PCM_does_not_exist").unwrap(), crate::Direction::Playback, false).err().unwrap();
assert_eq!(e.func(), "snd_pcm_open");
assert_eq!(e.errno(), nix::errno::Errno::ENOENT);
}