alsa/
error.rs

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

alsa/
error.rs
