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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;
use unicode_segmentation::UnicodeSegmentation;
/// 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(())
}
}
/// Wrapper struct which will emit the HTML-escaped version of the contained
/// string when passed to a format string.
///
/// This is only safe to use for text nodes. If you need your output to be
/// safely contained in an attribute, use [`Escape`]. If you don't know the
/// difference, use [`Escape`].
pub(crate) struct EscapeBodyText<'a>(pub &'a str);
impl<'a> fmt::Display for EscapeBodyText<'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 EscapeBodyText(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(())
}
}
/// Wrapper struct which will emit the HTML-escaped version of the contained
/// string when passed to a format string. This function also word-breaks
/// CamelCase and snake_case word names.
///
/// This is only safe to use for text nodes. If you need your output to be
/// safely contained in an attribute, use [`Escape`]. If you don't know the
/// difference, use [`Escape`].
pub(crate) struct EscapeBodyTextWithWbr<'a>(pub &'a str);
impl<'a> fmt::Display for EscapeBodyTextWithWbr<'a> {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
let EscapeBodyTextWithWbr(text) = *self;
if text.len() < 8 {
return EscapeBodyText(text).fmt(fmt);
}
let mut last = 0;
let mut it = text.grapheme_indices(true).peekable();
let _ = it.next(); // don't insert wbr before first char
while let Some((i, s)) = it.next() {
let pk = it.peek();
if s.chars().all(|c| c.is_whitespace()) {
// don't need "First <wbr>Second"; the space is enough
EscapeBodyText(&text[last..i]).fmt(fmt)?;
last = i;
continue;
}
let is_uppercase = || s.chars().any(|c| c.is_uppercase());
let next_is_uppercase =
|| pk.map_or(true, |(_, t)| t.chars().any(|c| c.is_uppercase()));
let next_is_underscore = || pk.map_or(true, |(_, t)| t.contains('_'));
let next_is_colon = || pk.map_or(true, |(_, t)| t.contains(':'));
if i - last > 3 && is_uppercase() && !next_is_uppercase() {
EscapeBodyText(&text[last..i]).fmt(fmt)?;
fmt.write_str("<wbr>")?;
last = i;
} else if (s.contains(':') && !next_is_colon())
|| (s.contains('_') && !next_is_underscore())
{
EscapeBodyText(&text[last..i + 1]).fmt(fmt)?;
fmt.write_str("<wbr>")?;
last = i + 1;
}
}
if last < text.len() {
EscapeBodyText(&text[last..]).fmt(fmt)?;
}
Ok(())
}
}
#[cfg(test)]
mod tests;