feat(text)!: add Masked to display secure data

[joshka]

Adds a new type Masked that can mask data with a mask character, and can be used anywhere we expect Cow<'a, str> or Text<'a>. E.g. Paragraph, ListItem, Table Cells etc.

BREAKING CHANGE:
Because Masked implements From for Text<'a>, code that binds Into<Text<'a>> without type annotations may no longer compile (e.g. Paragraph::new("".as_ref()))
To fix this, annotate or call to_string() / to_owned() / as_str()

This is an alternative to #32

[mindoodoo]

Awesome stuff, this looks great. Breaking change is relatively small and isn't an issue IMHO. I'd also add I much prefer this as opposed to #32, although it has the one of advantage of not having a breaking change.

[joshka]

Awesome stuff, this looks great. Breaking change is relatively small and isn't an issue IMHO. I'd also add I much prefer this as opposed to #32, although it has the one of advantage of not having a breaking change.

Yeah, I'm not sure I'd have noticed the breaking change if it wasn't for the two places where we have as_ref() calls. The impact is only really felt when there is some large string that's being copied (and the largest string that can be reasonably rendered on a screen isn't likely to ever be a perf issue, so meh). For this change I wouldn't bother with a major version bump ever. I only called it out as it's useful to have notes on what to fix when something breaks (or when assumptions about impact are wrong).

[mindoodoo]

For this change I wouldn't bother with a major version bump ever. I only called it out as it's useful to have notes on what to fix when something breaks (or when assumptions about impact are wrong).

I think the next release will most likely have breaking changes anyways so might as well slip it in with it.

[mindoodoo]

@joshka Regarding the information about the breaking change, did you find a way to be able to keep the commit footer and body on github ?

[joshka]

@joshka Regarding the information about the breaking change, did you find a way to be able to keep the commit footer and body on github ?

Yep merge / push changes via the cli rather than github. Rebase on main, test, push. Done. :)

[sophacles]

I like it. Nice feature.

Idea for expansion of it in the future:
Have an option to mask only a subset of the text, for example:

Choose how you'd like to receive your authorization code:
 Email: a*****@gmail.com
 Phone: ***-***-1234

Etc.

Maybe in the form of

// constructor or setter on Masked
// args to masker: input txt, mask_char
fn masker(self, masker: Fn(&str, &str) -> &str) -> Self {...}

[joshka]

Idea for expansion of it in the future:
Have an option to mask only a subset of the text, for example:

The main benefit of having this as part of the library is that it is useful in its simple form, but I think once you go beyond a certain complexity on this, it's probably more the user's responsibility to be the one that handles their own input / output, and this isn't all that difficult. An example of keeping that idea super simple:

struct MaskedCreditCard<'a> {
    card_number: &'a str,
}

impl<'a> MaskedCreditCard<'a> {
    pub fn new(card_number: &'a str) -> Self {
        // in a real app, should never have anything more than the last 4 digit available
        // but for the sake of an example
        MaskedCreditCard { card_number }
    }
}

impl Default for MaskedCreditCard<'_> {
    fn default() -> Self {
        MaskedCreditCard::new("0000-0000-0000-0000")
    }
}

impl<'a> From<MaskedCreditCard<'a>> for Cow<'a, str> {
    fn from(value: MaskedCreditCard) -> Self {
        ("****-****-****-".to_string() + value.card_number.rsplit_once('-').unwrap().1).into()
    }
}

[joshka]

Rebased on main

[sophacles]

Sure, not looking to make it complex, just was thinking it would allow the suer to handle the masking functionality for their own cases that aren't "all the text":

fn masked_credit_card(ccn: &str) -> Masked<'a> {
    Masked::new(ccn, "*").masker(|txt, mask| {
        let (to_mask, plain) = txt.rsplit_once('-').unwrap();
        let mut s = to_mask.replace(['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'], mask);
        s.push_str("-");
        s.push_str(plain);
    })
}

and the user could call it in something like:

Paragraph::new(masked_credit_card(ccn).mask_char("!"))