src/librustdoc/html/escape.rs

   1 // Copyright 2013 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 //! HTML Escaping
  12 //!
  13 //! This module contains one unit-struct which can be used to HTML-escape a
  14 //! string of text (for use in a format string).
  15
  16 use std::fmt;
  17
  18 /// Wrapper struct which will emit the HTML-escaped version of the contained
  19 /// string when passed to a format string.
  20 pub struct Escape<'a>(pub &'a str);
  21
  22 impl<'a> fmt::Display for Escape<'a> {
  23     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
  24         // Because the internet is always right, turns out there's not that many
  25         // characters to escape: http://stackoverflow.com/questions/7381974
  26         let Escape(s) = *self;
  27         let pile_o_bits = s;
  28         let mut last = 0;
  29         for (i, ch) in s.bytes().enumerate() {
  30             match ch as char {
  31                 '<' | '>' | '&' | '\'' | '"' => {
  32                     fmt.write_str(&pile_o_bits[last.. i])?;
  33                     let s = match ch as char {
  34                         '>' => "&gt;",
  35                         '<' => "&lt;",
  36                         '&' => "&amp;",
  37                         '\'' => "&#39;",
  38                         '"' => "&quot;",
  39                         _ => unreachable!()
  40                     };
  41                     fmt.write_str(s)?;
  42                     last = i + 1;
  43                 }
  44                 _ => {}
  45             }
  46         }
  47
  48         if last < s.len() {
  49             fmt.write_str(&pile_o_bits[last..])?;
  50         }
  51         Ok(())
  52     }
  53 }