#
cargo_util/
process_error.rs

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    //! Error value for [`crate::ProcessBuilder`] when a process fails.

    use std::fmt;
    use std::process::{ExitStatus, Output};
    use std::str;

    #[derive(Debug)]
    pub struct ProcessError {
        /// A detailed description to show to the user why the process failed.
        pub desc: String,

        /// The exit status of the process.
        ///
        /// This can be `None` if the process failed to launch (like process not
        /// found) or if the exit status wasn't a code but was instead something
        /// like termination via a signal.
        pub code: Option<i32>,

        /// The stdout from the process.
        ///
        /// This can be `None` if the process failed to launch, or the output was
        /// not captured.
        pub stdout: Option<Vec<u8>>,

        /// The stderr from the process.
        ///
        /// This can be `None` if the process failed to launch, or the output was
        /// not captured.
        pub stderr: Option<Vec<u8>>,
    }

    impl fmt::Display for ProcessError {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            self.desc.fmt(f)
        }
    }

    impl std::error::Error for ProcessError {}

    impl ProcessError {
        /// Creates a new [`ProcessError`].
        ///
        /// * `status` can be `None` if the process did not launch.
        /// * `output` can be `None` if the process did not launch, or output was not captured.
        pub fn new(msg: &str, status: Option<ExitStatus>, output: Option<&Output>) -> ProcessError {
            let exit = match status {
                Some(s) => exit_status_to_string(s),
                None => "never executed".to_string(),
            };

            Self::new_raw(
                msg,
                status.and_then(|s| s.code()),
                &exit,
                output.map(|s| s.stdout.as_slice()),
                output.map(|s| s.stderr.as_slice()),
            )
        }

        /// Creates a new [`ProcessError`] with the raw output data.
        ///
        /// * `code` can be `None` for situations like being killed by a signal on unix.
        pub fn new_raw(
            msg: &str,
            code: Option<i32>,
            status: &str,
            stdout: Option<&[u8]>,
            stderr: Option<&[u8]>,
        ) -> ProcessError {
            let mut desc = format!("{} ({})", msg, status);

            if let Some(out) = stdout {
                match str::from_utf8(out) {
                    Ok(s) if !s.trim().is_empty() => {
                        desc.push_str("\n--- stdout\n");
                        desc.push_str(s);
                    }
                    Ok(..) | Err(..) => {}
                }
            }
            if let Some(out) = stderr {
                match str::from_utf8(out) {
                    Ok(s) if !s.trim().is_empty() => {
                        desc.push_str("\n--- stderr\n");
                        desc.push_str(s);
                    }
                    Ok(..) | Err(..) => {}
                }
            }

            ProcessError {
                desc,
                code,
                stdout: stdout.map(|s| s.to_vec()),
                stderr: stderr.map(|s| s.to_vec()),
            }
        }

        /// Creates a [`ProcessError`] with "could not execute process {cmd}".
        ///
        /// * `cmd` is usually but not limited to [`std::process::Command`].
        pub fn could_not_execute(cmd: impl fmt::Display) -> ProcessError {
            ProcessError::new(&format!("could not execute process {cmd}"), None, None)
        }
    }

    /// Converts an [`ExitStatus`]  to a human-readable string suitable for
    /// displaying to a user.
    pub fn exit_status_to_string(status: ExitStatus) -> String {
        return status_to_string(status);

        #[cfg(unix)]
        fn status_to_string(status: ExitStatus) -> String {
            use std::os::unix::process::*;

            if let Some(signal) = status.signal() {
                let name = match signal as libc::c_int {
                    libc::SIGABRT => ", SIGABRT: process abort signal",
                    libc::SIGALRM => ", SIGALRM: alarm clock",
                    libc::SIGFPE => ", SIGFPE: erroneous arithmetic operation",
                    libc::SIGHUP => ", SIGHUP: hangup",
                    libc::SIGILL => ", SIGILL: illegal instruction",
                    libc::SIGINT => ", SIGINT: terminal interrupt signal",
                    libc::SIGKILL => ", SIGKILL: kill",
                    libc::SIGPIPE => ", SIGPIPE: write on a pipe with no one to read",
                    libc::SIGQUIT => ", SIGQUIT: terminal quit signal",
                    libc::SIGSEGV => ", SIGSEGV: invalid memory reference",
                    libc::SIGTERM => ", SIGTERM: termination signal",
                    libc::SIGBUS => ", SIGBUS: access to undefined memory",
                    #[cfg(not(target_os = "haiku"))]
                    libc::SIGSYS => ", SIGSYS: bad system call",
                    libc::SIGTRAP => ", SIGTRAP: trace/breakpoint trap",
                    _ => "",
                };
                format!("signal: {}{}", signal, name)
            } else {
                status.to_string()
            }
        }

        #[cfg(windows)]
        fn status_to_string(status: ExitStatus) -> String {
            use windows_sys::Win32::Foundation::*;

            let mut base = status.to_string();
            let extra = match status.code().unwrap() as i32 {
                STATUS_ACCESS_VIOLATION => "STATUS_ACCESS_VIOLATION",
                STATUS_IN_PAGE_ERROR => "STATUS_IN_PAGE_ERROR",
                STATUS_INVALID_HANDLE => "STATUS_INVALID_HANDLE",
                STATUS_INVALID_PARAMETER => "STATUS_INVALID_PARAMETER",
                STATUS_NO_MEMORY => "STATUS_NO_MEMORY",
                STATUS_ILLEGAL_INSTRUCTION => "STATUS_ILLEGAL_INSTRUCTION",
                STATUS_NONCONTINUABLE_EXCEPTION => "STATUS_NONCONTINUABLE_EXCEPTION",
                STATUS_INVALID_DISPOSITION => "STATUS_INVALID_DISPOSITION",
                STATUS_ARRAY_BOUNDS_EXCEEDED => "STATUS_ARRAY_BOUNDS_EXCEEDED",
                STATUS_FLOAT_DENORMAL_OPERAND => "STATUS_FLOAT_DENORMAL_OPERAND",
                STATUS_FLOAT_DIVIDE_BY_ZERO => "STATUS_FLOAT_DIVIDE_BY_ZERO",
                STATUS_FLOAT_INEXACT_RESULT => "STATUS_FLOAT_INEXACT_RESULT",
                STATUS_FLOAT_INVALID_OPERATION => "STATUS_FLOAT_INVALID_OPERATION",
                STATUS_FLOAT_OVERFLOW => "STATUS_FLOAT_OVERFLOW",
                STATUS_FLOAT_STACK_CHECK => "STATUS_FLOAT_STACK_CHECK",
                STATUS_FLOAT_UNDERFLOW => "STATUS_FLOAT_UNDERFLOW",
                STATUS_INTEGER_DIVIDE_BY_ZERO => "STATUS_INTEGER_DIVIDE_BY_ZERO",
                STATUS_INTEGER_OVERFLOW => "STATUS_INTEGER_OVERFLOW",
                STATUS_PRIVILEGED_INSTRUCTION => "STATUS_PRIVILEGED_INSTRUCTION",
                STATUS_STACK_OVERFLOW => "STATUS_STACK_OVERFLOW",
                STATUS_DLL_NOT_FOUND => "STATUS_DLL_NOT_FOUND",
                STATUS_ORDINAL_NOT_FOUND => "STATUS_ORDINAL_NOT_FOUND",
                STATUS_ENTRYPOINT_NOT_FOUND => "STATUS_ENTRYPOINT_NOT_FOUND",
                STATUS_CONTROL_C_EXIT => "STATUS_CONTROL_C_EXIT",
                STATUS_DLL_INIT_FAILED => "STATUS_DLL_INIT_FAILED",
                STATUS_FLOAT_MULTIPLE_FAULTS => "STATUS_FLOAT_MULTIPLE_FAULTS",
                STATUS_FLOAT_MULTIPLE_TRAPS => "STATUS_FLOAT_MULTIPLE_TRAPS",
                STATUS_REG_NAT_CONSUMPTION => "STATUS_REG_NAT_CONSUMPTION",
                STATUS_HEAP_CORRUPTION => "STATUS_HEAP_CORRUPTION",
                STATUS_STACK_BUFFER_OVERRUN => "STATUS_STACK_BUFFER_OVERRUN",
                STATUS_ASSERTION_FAILURE => "STATUS_ASSERTION_FAILURE",
                _ => return base,
            };
            base.push_str(", ");
            base.push_str(extra);
            base
        }
    }

    /// Returns `true` if the given process exit code is something a normal
    /// process would exit with.
    ///
    /// This helps differentiate from abnormal termination codes, such as
    /// segmentation faults or signals.
    pub fn is_simple_exit_code(code: i32) -> bool {
        // Typical unix exit codes are 0 to 127.
        // Windows doesn't have anything "typical", and is a
        // 32-bit number (which appears signed here, but is really
        // unsigned). However, most of the interesting NTSTATUS
        // codes are very large. This is just a rough
        // approximation of which codes are "normal" and which
        // ones are abnormal termination.
        code >= 0 && code <= 127
    }