securefmt 0.1.5

Drop-in replacement for the Debug derive macro that hides fields marked as sensitive.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

use core::fmt::{Display, Formatter};
use proc_macro2::Span;
use thiserror::Error;

pub type Result<T> = core::result::Result<T, SecureFmtError>;

#[derive(Error, Debug)]
pub struct SecureFmtError {
    pub call_site: Span,
    pub message: String,
}

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

macro_rules! secure_fmt_error {
    ($call_site:expr, $($arg:tt)+) => {{
        let message = std::fmt::format(std::format_args!($($arg)*));
        Err($crate::errors::SecureFmtError { call_site: $call_site, message })
    }}
}

#[cfg(test)]
mod tests {
    use super::Result;
    use pretty_assertions::assert_eq;
    use proc_macro2::Span;

    #[test]
    fn should_create_secure_fmt_error_with_message() {
        let result: Result<()> = secure_fmt_error!(Span::call_site(), "Bad stuff: {}", 42);
        let err = result.expect_err("Should have been an error");

        assert_eq!(
            format!("{:?}", err.call_site),
            format!("{:?}", Span::call_site())
        );
        assert_eq!(err.message, "Bad stuff: 42");
    }
}