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 pub 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.bytes().enumerate() {
  20             match ch as char {
  21                 '<' | '>' | '&' | '\'' | '"' => {
  22                     fmt.write_str(&pile_o_bits[last.. i])?;
  23                     let s = match ch as char {
  24                         '>' => "&gt;",
  25                         '<' => "&lt;",
  26                         '&' => "&amp;",
  27                         '\'' => "&#39;",
  28                         '"' => "&quot;",
  29                         _ => unreachable!()
  30                     };
  31                     fmt.write_str(s)?;
  32                     last = i + 1;
  33                 }
  34                 _ => {}
  35             }
  36         }
  37
  38         if last < s.len() {
  39             fmt.write_str(&pile_o_bits[last..])?;
  40         }
  41         Ok(())
  42     }
  43 }