alsa/
error.rs

1#![macro_use]
2
3use libc::{c_char, c_int, c_void, free};
4use core::error::Error as StdError;
5use core::ffi::CStr;
6use core::{fmt, str};
7use ::alloc::string::{String, ToString};
8
9/// ALSA error
10///
11/// Most ALSA functions can return a negative error code.
12/// If so, then that error code is wrapped into this `Error` struct.
13/// An Error is also returned in case ALSA returns a string that
14/// cannot be translated into Rust's UTF-8 strings.
15#[derive(Clone, PartialEq, Copy)]
16pub struct Error(&'static str, c_int);
17
18pub type Result<T> = ::core::result::Result<T, Error>;
19
20#[cfg(not(feature = "std"))]
21extern "C" {
22    pub(crate) static errno: c_int;
23}
24
25macro_rules! acheck {
26    ($f: ident ( $($x: expr),* ) ) => {{
27        let r = unsafe { alsa::$f( $($x),* ) };
28        if r < 0 { Err(Error::new(stringify!($f), -r as ::libc::c_int)) }
29        else { Ok(r) }
30    }}
31}
32
33pub fn from_const<'a>(func: &'static str, s: *const c_char) -> Result<&'a str> {
34    if s.is_null() {
35        return Err(invalid_str(func));
36    };
37    let cc = unsafe { CStr::from_ptr(s) };
38    str::from_utf8(cc.to_bytes()).map_err(|_| invalid_str(func))
39}
40
41pub fn from_alloc(func: &'static str, s: *mut c_char) -> Result<String> {
42    if s.is_null() {
43        return Err(invalid_str(func));
44    };
45    let c = unsafe { CStr::from_ptr(s) };
46    let ss = str::from_utf8(c.to_bytes())
47        .map_err(|_| {
48            unsafe {
49                free(s as *mut c_void);
50            }
51            invalid_str(func)
52        })?
53        .to_string();
54    unsafe {
55        free(s as *mut c_void);
56    }
57    Ok(ss)
58}
59
60pub fn from_code(func: &'static str, r: c_int) -> Result<c_int> {
61    if r < 0 {
62        Err(Error::new(func, r))
63    } else {
64        Ok(r)
65    }
66}
67
68impl Error {
69    pub fn new(func: &'static str, res: c_int) -> Error {
70        Self(func, res)
71    }
72
73    pub fn last(func: &'static str) -> Error {
74        #[cfg(feature = "std")] {
75            Self(
76                func,
77                std::io::Error::last_os_error().raw_os_error().unwrap_or_default(),
78            )
79        }
80        #[cfg(not(feature = "std"))] {
81            Self(
82                func,
83                unsafe {errno},
84            )
85        }
86    }
87
88    pub fn unsupported(func: &'static str) -> Error {
89        Error(func, libc::ENOTSUP)
90    }
91
92    /// The function which failed.
93    pub fn func(&self) -> &'static str {
94        self.0
95    }
96
97    /// Underlying error
98    ///
99    /// Match this against the re-export of `nix::Error` in this crate, not against a specific version
100    /// of the nix crate. The nix crate version might be updated with minor updates of this library.
101    pub fn errno(&self) -> i32 {
102        self.1
103    }
104}
105
106pub fn invalid_str(func: &'static str) -> Error {
107    Error(func, libc::EILSEQ)
108}
109
110impl StdError for Error {
111    fn description(&self) -> &str {
112        "ALSA error"
113    }
114}
115
116impl fmt::Debug for Error {
117    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
118        write!(f, "{}", self)
119    }
120}
121
122impl fmt::Display for Error {
123    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
124        write!(
125            f,
126            "ALSA function '{}' failed with error '{} ({})'",
127            self.0,
128            desc(self.1),
129            self.1,
130        )
131    }
132}
133
134/// See <https://github.com/nix-rust/nix/blob/197f55b3ccbce3273bf6ce119d1a8541b5df5d66/src/errno.rs#L198>
135///
136/// Note this doesn't include the total set of possible errno variants, but they
137/// can easily be added in the future for better error messages
138fn desc(err: i32) -> &'static str {
139    match err {
140        libc::EPERM => "Operation not permitted",
141        libc::ENOENT => "No such file or directory",
142        libc::ESRCH => "No such process",
143        libc::EINTR => "Interrupted system call",
144        libc::EIO => "I/O error",
145        libc::ENXIO => "No such device or address",
146        libc::E2BIG => "Argument list too long",
147        libc::ENOEXEC => "Exec format error",
148        libc::EBADF => "Bad file number",
149        libc::ECHILD => "No child processes",
150        libc::EAGAIN => "Try again",
151        libc::ENOMEM => "Out of memory",
152        libc::EACCES => "Permission denied",
153        libc::EFAULT => "Bad address",
154        libc::ENOTBLK => "Block device required",
155        libc::EBUSY => "Device or resource busy",
156        libc::EEXIST => "File exists",
157        libc::EXDEV => "Cross-device link",
158        libc::ENODEV => "No such device",
159        libc::ENOTDIR => "Not a directory",
160        libc::EISDIR => "Is a directory",
161        libc::EINVAL => "Invalid argument",
162        libc::ENFILE => "File table overflow",
163        libc::EMFILE => "Too many open files",
164        libc::ENOTTY => "Not a typewriter",
165        libc::ETXTBSY => "Text file busy",
166        libc::EFBIG => "File too large",
167        libc::ENOSPC => "No space left on device",
168        libc::ESPIPE => "Illegal seek",
169        libc::EROFS => "Read-only file system",
170        libc::EMLINK => "Too many links",
171        libc::EPIPE => "Broken pipe",
172        libc::EDOM => "Math argument out of domain of func",
173        libc::ERANGE => "Math result not representable",
174        libc::EDEADLK => "Resource deadlock would occur",
175        libc::ENAMETOOLONG => "File name too long",
176        libc::ENOLCK => "No record locks available",
177        libc::ENOSYS => "Function not implemented",
178        libc::ENOTEMPTY => "Directory not empty",
179        libc::ELOOP => "Too many symbolic links encountered",
180        libc::ENOMSG => "No message of desired type",
181        libc::EIDRM => "Identifier removed",
182        libc::EINPROGRESS => "Operation now in progress",
183        libc::EALREADY => "Operation already in progress",
184        libc::ENOTSOCK => "Socket operation on non-socket",
185        libc::EDESTADDRREQ => "Destination address required",
186        libc::EMSGSIZE => "Message too long",
187        libc::EPROTOTYPE => "Protocol wrong type for socket",
188        libc::ENOPROTOOPT => "Protocol not available",
189        libc::EPROTONOSUPPORT => "Protocol not supported",
190        libc::ESOCKTNOSUPPORT => "Socket type not supported",
191        libc::EPFNOSUPPORT => "Protocol family not supported",
192        libc::EAFNOSUPPORT => "Address family not supported by protocol",
193        libc::EADDRINUSE => "Address already in use",
194        libc::EADDRNOTAVAIL => "Cannot assign requested address",
195        libc::ENETDOWN => "Network is down",
196        libc::ENETUNREACH => "Network is unreachable",
197        libc::ENETRESET => "Network dropped connection because of reset",
198        libc::ECONNABORTED => "Software caused connection abort",
199        libc::ECONNRESET => "Connection reset by peer",
200        libc::ENOBUFS => "No buffer space available",
201        libc::EISCONN => "Transport endpoint is already connected",
202        libc::ENOTCONN => "Transport endpoint is not connected",
203        libc::ESHUTDOWN => "Cannot send after transport endpoint shutdown",
204        libc::ETOOMANYREFS => "Too many references: cannot splice",
205        libc::ETIMEDOUT => "Connection timed out",
206        libc::ECONNREFUSED => "Connection refused",
207        libc::EHOSTDOWN => "Host is down",
208        libc::EHOSTUNREACH => "No route to host",
209        libc::ENOTSUP => "Operation not supported",
210        _ => "Unknown errno",
211    }
212}
213
214impl From<Error> for fmt::Error {
215    fn from(_: Error) -> fmt::Error {
216        fmt::Error
217    }
218}
219
220#[test]
221fn broken_pcm_name() {
222    use ::alloc::ffi::CString;
223    let e = crate::PCM::open(
224        &*CString::new("this_PCM_does_not_exist").unwrap(),
225        crate::Direction::Playback,
226        false,
227    )
228    .err()
229    .unwrap();
230    assert_eq!(e.func(), "snd_pcm_open");
231    assert_eq!(e.errno(), libc::ENOENT);
232}
alsa/error.rs

alsa/
error.rs
