one_err

OneErr 一统天下。

有些出色的错误辅助 crate，我最喜欢的有 thiserror 和 anyhow。

但有时候你需要一些不同的东西。随着时间的推移，thiserror crate 可能会导致巨大的嵌套错误枚举树，而 anyhow 很难匹配。

有时候你需要与 std::io::Error 交互，但这种类型难以构造，不是 Clone，并且无法序列化。

OneErr 是在 std::io::Error 上的新类型，但使其可克隆、可序列化，并希望更易于使用。

std::io::ErrorKind 匹配

use one_err::*;

for res in [
    Ok("not-error"),
    Err(OneErr::from(std::io::ErrorKind::InvalidInput)),
    Err(OneErr::from(std::io::ErrorKind::ConnectionRefused)),
] {
    match res.map_err(|e| e.kind()) {
        Ok(ok) => assert_eq!("not-error", ok),
        Err(std::io::ErrorKind::InvalidInput) => (),
        Err(std::io::ErrorKind::ConnectionRefused) => (),
        oth => panic!("unexpected: {:?}", oth),
    }
}

ErrNo 匹配

use one_err::*;

for res in [
    Ok("not-error"),
    Err(OneErr::from(ErrNo::NoData)),
    Err(OneErr::from(ErrNo::Proto)),
] {
    match res.map_err(|e| e.errno()) {
        Ok(ok) => assert_eq!("not-error", ok),
        Err(ErrNo::NoData) => (),
        Err(ErrNo::Proto) => (),
        oth => panic!("unexpected: {:?}", oth),
    }
}

自定义匹配

use one_err::*;

const ERR_FOO: &str = "FOO";
const ERR_BAR: &str = "BAR";

for res in [
    Ok("not-error"),
    Err(OneErr::with_message(ERR_FOO, "foo test")),
    Err(OneErr::with_message(ERR_BAR, "bar test")),
] {
    match res.as_ref().map_err(|e| (e.str_kind(), e)) {
        Ok(ok) => assert_eq!("not-error", *ok),
        Err((ERR_FOO, e)) => assert_eq!("foo test", e.get_message().unwrap()),
        Err((ERR_BAR, e)) => assert_eq!("bar test", e.get_message().unwrap()),
        oth => panic!("unexpected: {:?}", oth),
    }
}

std::io 互操作性

use one_err::*;
use std::io::Read;

const CUSTOM_ERR: &str = "CustomError";

/// My custom Read that always errors.
pub struct ErrReader;

impl Read for ErrReader {
    fn read(&mut self, _buf: &mut [u8]) -> std::io::Result<usize> {
        Err(OneErr::new(CUSTOM_ERR).into())
    }
}

assert_eq!(
    r#"{"error":"CustomError"}"#,
    &ErrReader.read(&mut []).unwrap_err().to_string(),
);

序列化和解析

use one_err::*;

const CUSTOM_ERR: &str = "CustomError";

let err = OneErr::new(CUSTOM_ERR);
let enc = err.to_string();

assert_eq!(
    r#"{"error":"CustomError"}"#,
    &enc,
);

let dec: OneErr = enc.parse().unwrap();
assert_eq!(err, dec);

许可：Apache-2.0