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//! HTML escaping.
//!
//! This module contains one unit struct, which can be used to HTML-escape a
//! string of text (for use in a format string).
use std::fmt;
/// Wrapper struct which will emit the HTML-escaped version of the contained
/// string when passed to a format string.
pub(crate) struct Escape<'a>(pub &'a str);
impl<'a> fmt::Display for Escape<'a> {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
// Because the internet is always right, turns out there's not that many
// characters to escape: http://stackoverflow.com/questions/7381974
let Escape(s) = *self;
let pile_o_bits = s;
let mut last = 0;
for (i, ch) in s.char_indices() {
let s = match ch {
'>' => ">",
'<' => "<",
'&' => "&",
'\'' => "'",
'"' => """,
_ => continue,
};
fmt.write_str(&pile_o_bits[last..i])?;
fmt.write_str(s)?;
// NOTE: we only expect single byte characters here - which is fine as long as we
// only match single byte characters
last = i + 1;
}
if last < s.len() {
fmt.write_str(&pile_o_bits[last..])?;
}
Ok(())
}
}