vendor/errno-0.2.8/src/lib.rs

   1 //! Cross-platform interface to the `errno` variable.
   2 //!
   3 //! # Examples
   4 //! ```
   5 //! use errno::{Errno, errno, set_errno};
   6 //!
   7 //! // Get the current value of errno
   8 //! let e = errno();
   9 //!
  10 //! // Set the current value of errno
  11 //! set_errno(e);
  12 //!
  13 //! // Extract the error code as an i32
  14 //! let code = e.0;
  15 //!
  16 //! // Display a human-friendly error message
  17 //! println!("Error {}: {}", code, e);
  18 //! ```
  19
  20 #![cfg_attr(target_os = "wasi", feature(thread_local))]
  21 #![cfg_attr(not(feature = "std"), no_std)]
  22
  23 #[cfg(unix)] extern crate libc;
  24 #[cfg(windows)] extern crate winapi;
  25 #[cfg(target_os = "dragonfly")] extern crate errno_dragonfly;
  26 #[cfg(target_os = "wasi")] extern crate libc;
  27 #[cfg(target_os = "hermit")] extern crate libc;
  28
  29 #[cfg_attr(unix, path = "unix.rs")]
  30 #[cfg_attr(windows, path = "windows.rs")]
  31 #[cfg_attr(target_os = "wasi", path = "wasi.rs")]
  32 #[cfg_attr(target_os = "hermit", path = "hermit.rs")]
  33 mod sys;
  34
  35 #[cfg(feature = "std")]
  36 use std::fmt;
  37 #[cfg(feature = "std")]
  38 use std::io;
  39 #[cfg(feature = "std")]
  40 use std::error::Error;
  41
  42 /// Wraps a platform-specific error code.
  43 ///
  44 /// The `Display` instance maps the code to a human-readable string. It
  45 /// calls [`strerror_r`][1] under POSIX, and [`FormatMessageW`][2] on
  46 /// Windows.
  47 ///
  48 /// [1]: http://pubs.opengroup.org/onlinepubs/009695399/functions/strerror.html
  49 /// [2]: https://msdn.microsoft.com/en-us/library/windows/desktop/ms679351%28v=vs.85%29.aspx
  50 #[derive(Copy, Clone, Eq, Ord, PartialEq, PartialOrd, Hash)]
  51 pub struct Errno(pub i32);
  52
  53 #[cfg(feature = "std")]
  54 impl fmt::Debug for Errno {
  55     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
  56         sys::with_description(*self, |desc| {
  57             fmt.debug_struct("Errno")
  58                 .field("code", &self.0)
  59                 .field("description", &desc.ok())
  60                 .finish()
  61         })
  62     }
  63 }
  64
  65 #[cfg(feature = "std")]
  66 impl fmt::Display for Errno {
  67     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
  68         sys::with_description(*self, |desc| match desc {
  69             Ok(desc) => fmt.write_str(&desc),
  70             Err(fm_err) => write!(
  71                 fmt, "OS error {} ({} returned error {})",
  72                 self.0, sys::STRERROR_NAME, fm_err.0),
  73         })
  74     }
  75 }
  76
  77 impl Into<i32> for Errno {
  78     fn into(self) -> i32 {
  79         self.0
  80     }
  81 }
  82
  83 #[cfg(feature = "std")]
  84 impl Error for Errno {
  85     // TODO: Remove when MSRV >= 1.27
  86     #[allow(deprecated)]
  87     fn description(&self) -> &str {
  88         "system error"
  89     }
  90 }
  91
  92 #[cfg(feature = "std")]
  93 impl From<Errno> for io::Error {
  94     fn from(errno: Errno) -> Self {
  95         io::Error::from_raw_os_error(errno.0)
  96     }
  97 }
  98
  99 /// Returns the platform-specific value of `errno`.
 100 pub fn errno() -> Errno {
 101     sys::errno()
 102 }
 103
 104 /// Sets the platform-specific value of `errno`.
 105 pub fn set_errno(err: Errno) {
 106     sys::set_errno(err)
 107 }
 108
 109 #[test]
 110 fn it_works() {
 111     let x = errno();
 112     set_errno(x);
 113 }
 114
 115 #[cfg(feature = "std")]
 116 #[test]
 117 fn it_works_with_to_string() {
 118     let x = errno();
 119     let _ = x.to_string();
 120 }
 121
 122 #[cfg(feature = "std")]
 123 #[test]
 124 fn check_description() {
 125     let expect = if cfg!(windows) {
 126         "Incorrect function."
 127     } else if cfg!(target_os = "illumos") {
 128         "Not owner"
 129     } else if cfg!(target_os = "wasi") {
 130         "Argument list too long"
 131     } else {
 132         "Operation not permitted"
 133     };
 134
 135     set_errno(Errno(1));
 136
 137     assert_eq!(errno().to_string(), expect);
 138     assert_eq!(
 139         format!("{:?}", errno()),
 140         format!("Errno {{ code: 1, description: Some({:?}) }}", expect));
 141 }
 142
 143 #[cfg(feature = "std")]
 144 #[test]
 145 fn check_error_into_errno() {
 146     const ERROR_CODE: i32 = 1;
 147
 148     let error = io::Error::from_raw_os_error(ERROR_CODE);
 149     let new_error: io::Error = Errno(ERROR_CODE).into();
 150     assert_eq!(error.kind(), new_error.kind());
 151 }