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Remove unsafe { … } code from askama_escape

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Using only safe code is actually same as fast as the previous "unsafe"
code according to the crate's benchmark.

The code was extracted from [markup]'s escape function in [escape.rs],
written by Utkarsh Kukreti <utkarshkukreti@gmail.com>, licensed as
`MIT OR Apache-2.0`.

[markup]: https://crates.io/crates/markup
[escape.rs]: 8ec4042848/markup/src/escape.rs (L1-L21)
This commit is contained in:
René Kijewski 2022-04-13 11:50:10 +02:00 committed by Dirkjan Ochtman
parent ab39ced64e
commit fc779e22c3
1 changed files with 34 additions and 50 deletions
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84
askama_escape/src/lib.rs
View File

@ -107,40 +107,31 @@ where
pub struct Html;
macro_rules! escaping_body {
($start:ident, $i:ident, $fmt:ident, $bytes:ident, $quote:expr) => {{
if $start < $i {
$fmt.write_str(unsafe { str::from_utf8_unchecked(&$bytes[$start..$i]) })?;
}
$fmt.write_str($quote)?;
$start = $i + 1;
}};
}
impl Escaper for Html {
fn write_escaped<W>(&self, mut fmt: W, string: &str) -> fmt::Result
where
W: Write,
{
let bytes = string.as_bytes();
let mut start = 0;
for (i, b) in bytes.iter().enumerate() {
if b.wrapping_sub(b'"') <= FLAG {
match *b {
b'<' => escaping_body!(start, i, fmt, bytes, "&lt;"),
b'>' => escaping_body!(start, i, fmt, bytes, "&gt;"),
b'&' => escaping_body!(start, i, fmt, bytes, "&amp;"),
b'"' => escaping_body!(start, i, fmt, bytes, "&quot;"),
b'\'' => escaping_body!(start, i, fmt, bytes, "&#x27;"),
_ => (),
}
let mut last = 0;
for (index, byte) in string.bytes().enumerate() {
macro_rules! go {
($expr:expr) => {{
fmt.write_str(&string[last..index])?;
fmt.write_str($expr)?;
last = index + 1;
}};
}
match byte {
b'<' => go!("&lt;"),
b'>' => go!("&gt;"),
b'&' => go!("&amp;"),
b'"' => go!("&quot;"),
b'\'' => go!("&#x27;"),
_ => {}
}
}
if start < bytes.len() {
fmt.write_str(unsafe { str::from_utf8_unchecked(&bytes[start..]) })
} else {
Ok(())
}
fmt.write_str(&string[last..])
}
}
@ -170,8 +161,6 @@ pub trait Escaper {
W: Write;
}
const FLAG: u8 = b'>' - b'"';
/// Escape chevrons, ampersand and apostrophes for use in JSON
#[cfg(feature = "json")]
#[derive(Debug, Clone, Default)]
@ -191,30 +180,25 @@ impl JsonEscapeBuffer {
#[cfg(feature = "json")]
impl std::io::Write for JsonEscapeBuffer {
fn write(&mut self, bytes: &[u8]) -> std::io::Result<usize> {
macro_rules! push_esc_sequence {
($start:ident, $i:ident, $self:ident, $bytes:ident, $quote:expr) => {{
if $start < $i {
$self.0.extend_from_slice(&$bytes[$start..$i]);
}
$self.0.extend_from_slice($quote);
$start = $i + 1;
}};
}
let mut last = 0;
for (index, byte) in bytes.iter().enumerate() {
macro_rules! go {
($expr:expr) => {{
self.0.extend(&bytes[last..index]);
self.0.extend($expr);
last = index + 1;
}};
}
self.0.reserve(bytes.len());
let mut start = 0;
for (i, b) in bytes.iter().enumerate() {
match *b {
b'&' => push_esc_sequence!(start, i, self, bytes, br#"\u0026"#),
b'\'' => push_esc_sequence!(start, i, self, bytes, br#"\u0027"#),
b'<' => push_esc_sequence!(start, i, self, bytes, br#"\u003c"#),
b'>' => push_esc_sequence!(start, i, self, bytes, br#"\u003e"#),
_ => (),
match byte {
b'&' => go!(br#"\u0026"#),
b'\'' => go!(br#"\u0027"#),
b'<' => go!(br#"\u003c"#),
b'>' => go!(br#"\u003e"#),
_ => {}
}
}
if start < bytes.len() {
self.0.extend_from_slice(&bytes[start..]);
}
self.0.extend(&bytes[last..]);
Ok(bytes.len())
}