src/librustdoc/html/escape.rs

   1 //! HTML escaping.
   2 //!
   3 //! This module contains one unit struct, which can be used to HTML-escape a
   4 //! string of text (for use in a format string).
   5
   6 use std::fmt;
   7
   8 /// Wrapper struct which will emit the HTML-escaped version of the contained
   9 /// string when passed to a format string.
  10 crate struct Escape<'a>(pub &'a str);
  11
  12 impl<'a> fmt::Display for Escape<'a> {
  13     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
  14         // Because the internet is always right, turns out there's not that many
  15         // characters to escape: http://stackoverflow.com/questions/7381974
  16         let Escape(s) = *self;
  17         let pile_o_bits = s;
  18         let mut last = 0;
  19         for (i, ch) in s.char_indices() {
  20             let s = match ch {
  21                 '>' => "&gt;",
  22                 '<' => "&lt;",
  23                 '&' => "&amp;",
  24                 '\'' => "&#39;",
  25                 '"' => "&quot;",
  26                 _ => continue,
  27             };
  28             fmt.write_str(&pile_o_bits[last..i])?;
  29             fmt.write_str(s)?;
  30             // NOTE: we only expect single byte characters here - which is fine as long as we
  31             // only match single byte characters
  32             last = i + 1;
  33         }
  34
  35         if last < s.len() {
  36             fmt.write_str(&pile_o_bits[last..])?;
  37         }
  38         Ok(())
  39     }
  40 }