lib.rs

//! Preferred system exit codes as defined by sysexits.h
//!
//! Exit code constants intended to be passed to
//! `std::process::exit()`
//!
//! # Example:
//! ```
//! extern crate exitcode;
//!
//! ::std::process::exit(exitcode::OK);
//! ```

/// Alias for the numeric type that holds system exit codes.
#[derive(Copy, Clone, PartialEq, Eq)]
pub struct ExitCode(i32);

impl From<ExitCode> for i32 {
    fn from(ec: ExitCode) -> i32 {
        ec.0
    }
}

impl std::fmt::Display for ExitCode {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

impl std::process::Termination for ExitCode {
    fn report(self) -> std::process::ExitCode {
        std::process::ExitCode::from(self.0 as u8) // safe because our highest exit code fits in u8
    }
}

/// Successful exit
pub const OK: ExitCode = ExitCode(0);

/// The command was used incorrectly, e.g., with the
/// wrong number of arguments, a bad flag, a bad syntax
/// in a parameter, etc.
pub const USAGE: ExitCode = ExitCode(64);

/// The input data was incorrect in some way.  This
/// should only be used for user's data and not system
/// files.
pub const DATAERR: ExitCode = ExitCode(65);

/// An input file (not a system file) did not exist or
/// was not readable.  This could also include errors
/// like "No message" to a mailer (if it cared to
/// catch it).
pub const NOINPUT: ExitCode = ExitCode(66);

/// The user specified did not exist.  This might be
/// used for mail addresses or remote logins.
pub const NOUSER: ExitCode = ExitCode(67);

/// The host specified did not exist.  This is used in
/// mail addresses or network requests.
pub const NOHOST: ExitCode = ExitCode(68);

/// A service is unavailable.  This can occur if a
/// support program or file does not exist. This can also
/// be used as a catchall message when something you
/// wanted to do doesn't work, but you don't know why.
pub const UNAVAILABLE: ExitCode = ExitCode(69);

/// An internal software error has been detected.  This
/// should be limited to non-operating system related
/// errors as possible.
pub const SOFTWARE: ExitCode = ExitCode(70);

/// An operating system error has been detected.  This
/// is intended to be used for such things as "cannot
/// fork", "cannot create pipe", or the like.  It
/// includes things like getuid returning a user that
/// does not exist in the passwd file.
pub const OSERR: ExitCode = ExitCode(71);

/// Some system file (e.g., /etc/passwd, /var/run/utmp,
/// etc.) does not exist, cannot be opened, or has some
/// sort of error (e.g., syntax error).
pub const OSFILE: ExitCode = ExitCode(72);

/// A (user specified) output file cannot be created.
pub const CANTCREAT: ExitCode = ExitCode(73);

/// An error occurred while doing I/O on some file.
pub const IOERR: ExitCode = ExitCode(74);

/// Temporary failure, indicating something that is not
/// really an error.  In sendmail, this means that a
/// mailer (e.g.) could not create a connection, and
/// the request should be reattempted later.
pub const TEMPFAIL: ExitCode = ExitCode(75);

/// The remote system returned something that was
/// "not possible" during a protocol exchange.
pub const PROTOCOL: ExitCode = ExitCode(76);

/// You did not have sufficient permission to perform
/// the operation.  This is not intended for file system
/// problems, which should use `NOINPUT` or `CANTCREAT`,
/// but rather for higher level permissions.
pub const NOPERM: ExitCode = ExitCode(77);

/// Something was found in an unconfigured or misconfigured state.
pub const CONFIG: ExitCode = ExitCode(78);

/// Check if exit code given by `code` is successful
///
/// # Example:
/// ```
/// extern crate exitcode;
///
/// assert!(exitcode::is_success(exitcode::OK));
/// assert!(!exitcode::is_success(exitcode::USAGE));
/// assert!(exitcode::is_success(0));
/// ```
pub fn is_success(code: ExitCode) -> bool {
    code == OK
}

/// Check if exit code given by `code` is an error
///
/// # Example:
/// ```
/// extern crate exitcode;
///
/// assert!(exitcode::is_error(exitcode::USAGE));
/// assert!(!exitcode::is_error(exitcode::OK));
/// assert!(exitcode::is_error(1));
/// ```
pub fn is_error(code: ExitCode) -> bool {
    !is_success(code)
}