minify-html/rust/common/src/spec/entity/encode.rs

63 lines
2.6 KiB
Rust

use aho_corasick::{AhoCorasick, AhoCorasickBuilder, MatchKind};
use lazy_static::lazy_static;
use memchr::memchr;
use crate::gen::codepoints::ALPHANUMERIC_OR_EQUALS;
use crate::gen::entities::{
EntityType, ENTITY, SHORTER_ENCODED_ENTITIES_DECODED, SHORTER_ENCODED_ENTITIES_ENCODED,
};
use crate::pattern::TrieNodeMatch;
lazy_static! {
static ref SHORTER_ENCODED_ENTITIES_ENCODED_SEARCHER: AhoCorasick = AhoCorasickBuilder::new()
.dfa(true)
.match_kind(MatchKind::LeftmostLongest)
.build(SHORTER_ENCODED_ENTITIES_DECODED);
}
// Encodes ampersands when necessary, as well as UTF-8 sequences that are shorter encoded.
// Does not handle context-specific escaping e.g. `>`, `'`, `"`.
pub fn encode_entities(mut code: &[u8], in_attr_val: bool) -> Vec<u8> {
let mut res = Vec::<u8>::new();
while !code.is_empty() {
let (before, matched) = match memchr(b'&', code) {
None => (code.len(), false),
Some(n) => (n, true),
};
res.extend_from_slice(&code[..before]);
code = &code[before..];
if matched {
let (start, end) = match ENTITY.longest_matching_prefix(code) {
// Entity is malformed, so we can just ignore it.
TrieNodeMatch::NotFound { reached } => (0, reached),
TrieNodeMatch::Found { len, value } => (
match value {
EntityType::Named(_)
if in_attr_val
&& code[len - 1] != b';'
&& code
.get(len)
.filter(|&&c| ALPHANUMERIC_OR_EQUALS[c])
.is_some() =>
{
// A named entity inside an attribute value that doesn't end with semicolon but is followed by an alphanumeric or `=` character is not decoded, so we don't need to encode.
// https://html.spec.whatwg.org/multipage/parsing.html#named-character-reference-state.
0
}
_ => {
res.extend_from_slice(b"&amp");
// Skip the leading ampersand, as it will be replaced by `&amp`.
1
}
},
len,
),
};
res.extend_from_slice(&code[start..end]);
code = &code[end..];
};
}
SHORTER_ENCODED_ENTITIES_ENCODED_SEARCHER
.replace_all_bytes(&res, SHORTER_ENCODED_ENTITIES_ENCODED)
}