script: Move extended_filtering to the style crate.

We'll need to call it from the style crate in later patches, when matching
:lang() against element snapshots.
This commit is contained in:
Cameron McCormack 2017-06-06 12:44:17 +08:00
parent 07b0770d21
commit 524794c09a
4 changed files with 69 additions and 64 deletions

View file

@ -113,63 +113,6 @@ pub fn is_token(s: &[u8]) -> bool {
})
}
/// Returns whether the language is matched, as defined by
/// [RFC 4647](https://tools.ietf.org/html/rfc4647#section-3.3.2).
pub fn extended_filtering(tag: &str, range: &str) -> bool {
let lang_ranges: Vec<&str> = range.split(',').collect();
lang_ranges.iter().any(|&lang_range| {
// step 1
let range_subtags: Vec<&str> = lang_range.split('\x2d').collect();
let tag_subtags: Vec<&str> = tag.split('\x2d').collect();
let mut range_iter = range_subtags.iter();
let mut tag_iter = tag_subtags.iter();
// step 2
// Note: [Level-4 spec](https://drafts.csswg.org/selectors/#lang-pseudo) check for wild card
if let (Some(range_subtag), Some(tag_subtag)) = (range_iter.next(), tag_iter.next()) {
if !(range_subtag.eq_ignore_ascii_case(tag_subtag) || range_subtag.eq_ignore_ascii_case("*")) {
return false;
}
}
let mut current_tag_subtag = tag_iter.next();
// step 3
for range_subtag in range_iter {
// step 3a
if range_subtag.eq_ignore_ascii_case("*") {
continue;
}
match current_tag_subtag.clone() {
Some(tag_subtag) => {
// step 3c
if range_subtag.eq_ignore_ascii_case(tag_subtag) {
current_tag_subtag = tag_iter.next();
continue;
} else {
// step 3d
if tag_subtag.len() == 1 {
return false;
} else {
// else step 3e - continue with loop
current_tag_subtag = tag_iter.next();
if current_tag_subtag.is_none() {
return false;
}
}
}
},
// step 3b
None => { return false; }
}
}
// step 4
true
})
}
/// A DOMString.
///