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::Show 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.as_slice();
28 let mut last = 0;
29 for (i, ch) in s.bytes().enumerate() {
30 match ch as char {
31 '<' | '>' | '&' | '\'' | '"' => {
32 try!(fmt.buf.write(pile_o_bits.slice(last, i).as_bytes()));
33 let s = match ch as char {
34 '>' => ">",
35 '<' => "<",
36 '&' => "&",
37 '\'' => "'",
38 '"' => """,
39 _ => unreachable!()
40 };
41 try!(fmt.buf.write(s.as_bytes()));
42 last = i + 1;
43 }
44 _ => {}
45 }
46 }
47
48 if last < s.len() {
49 try!(fmt.buf.write(pile_o_bits.slice_from(last).as_bytes()));
50 }
51 Ok(())
52 }
53 }