329 lines
8.9 KiB
Rust
329 lines
8.9 KiB
Rust
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use crate::CowStr;
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use crate::DiscontinuousString;
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use crate::Span;
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use State::*;
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pub fn valid<I: Iterator<Item = char>>(chars: I) -> bool {
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!Parser::new(chars).any(|e| matches!(e, Element::Invalid))
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}
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// Attributes are relatively rare, we choose to pay 8 bytes always and sometimes an extra
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// indirection instead of always 24 bytes.
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#[derive(Debug, Clone, PartialEq, Eq, Default)]
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pub struct Attributes<'s>(Option<Box<Vec<(&'s str, CowStr<'s>)>>>);
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impl<'s> Attributes<'s> {
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#[must_use]
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pub fn new() -> Self {
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Self::default()
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}
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#[must_use]
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pub fn take(&mut self) -> Self {
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Self(self.0.take())
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}
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pub(crate) fn parse<S: DiscontinuousString<'s>>(&mut self, input: &S) -> bool {
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for elem in Parser::new(input.chars()) {
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match elem {
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Element::Class(c) => self.add("class", input.src(c)),
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Element::Identifier(i) => self.add("id", input.src(i)),
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Element::Attribute(a, v) => self.add(
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match input.src(a) {
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CowStr::Owned(_) => panic!(),
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CowStr::Borrowed(s) => s,
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},
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input.src(v),
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),
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Element::Invalid => return false,
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}
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}
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true
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}
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fn add(&mut self, attr: &'s str, val: CowStr<'s>) {
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if self.0.is_none() {
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self.0 = Some(Vec::new().into());
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};
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let attrs = self.0.as_mut().unwrap();
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attrs.push((attr, val));
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}
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#[cfg(test)]
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pub fn iter(&self) -> impl Iterator<Item = (&'s str, &str)> + '_ {
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self.0
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.iter()
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.flat_map(|v| v.iter().map(|(a, b)| (*a, b.as_ref())))
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}
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}
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#[cfg(test)]
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impl<'s> FromIterator<(&'s str, &'s str)> for Attributes<'s> {
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fn from_iter<I: IntoIterator<Item = (&'s str, &'s str)>>(iter: I) -> Self {
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let attrs = iter
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.into_iter()
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.map(|(a, v)| (a, v.into()))
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.collect::<Vec<_>>();
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if attrs.is_empty() {
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Attributes::new()
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} else {
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Attributes(Some(attrs.into()))
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}
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}
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}
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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enum State {
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Start,
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Whitespace,
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Comment,
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ClassFirst,
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Class,
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IdentifierFirst,
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Identifier,
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Attribute,
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ValueFirst,
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Value,
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ValueQuoted,
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Done,
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Invalid,
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}
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struct Parser<I> {
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chars: I,
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pos: usize,
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state: State,
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}
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impl<I: Iterator<Item = char>> Parser<I> {
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fn new(chars: I) -> Self {
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Parser {
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chars,
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pos: 0,
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state: Start,
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}
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}
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fn step_char(&mut self) -> Option<State> {
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self.chars.next().map(|c| {
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self.pos += c.len_utf8();
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match self.state {
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Start => match c {
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'{' => Whitespace,
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c if c.is_whitespace() => Start,
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_ => Invalid,
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},
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Whitespace => match c {
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'}' => Done,
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'.' => ClassFirst,
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'#' => IdentifierFirst,
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'%' => Comment,
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c if c.is_ascii_alphanumeric() || matches!(c, '_' | ':' | '-') => Attribute,
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c if c.is_whitespace() => Whitespace,
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_ => Invalid,
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},
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Comment => {
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if c == '%' {
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Whitespace
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} else {
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Comment
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}
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}
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s @ (ClassFirst | IdentifierFirst) => {
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if is_name_start(c) {
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match s {
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ClassFirst => Class,
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IdentifierFirst => Identifier,
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_ => panic!(),
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}
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} else {
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Invalid
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}
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}
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s @ (Class | Identifier | Value) => {
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if is_name(c) {
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s
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} else if c.is_whitespace() {
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Whitespace
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} else if c == '}' {
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Done
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} else {
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Invalid
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}
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}
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Attribute => {
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if is_name(c) {
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Attribute
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} else if c == '=' {
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ValueFirst
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} else {
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Invalid
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}
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}
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ValueFirst => {
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if is_name(c) {
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Value
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} else if c == '"' {
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ValueQuoted
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} else {
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Invalid
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}
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}
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ValueQuoted => {
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if c == '"' {
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Whitespace
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} else {
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ValueQuoted
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}
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}
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Done => {
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if c.is_whitespace() {
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Done
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} else {
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Invalid
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}
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}
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Invalid => panic!(),
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}
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})
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}
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fn step(&mut self) -> (State, Span) {
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let start = self.pos.saturating_sub(1);
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while let Some(state_next) = self.step_char() {
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if self.state != state_next {
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return (
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std::mem::replace(&mut self.state, state_next),
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Span::new(start, self.pos - 1),
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);
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}
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}
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(
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if self.state == Done { Done } else { Invalid },
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Span::new(start, self.pos),
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)
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}
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}
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fn is_name_start(c: char) -> bool {
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c.is_ascii_alphanumeric() || matches!(c, '_' | ':')
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}
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fn is_name(c: char) -> bool {
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is_name_start(c) || c.is_ascii_digit() || matches!(c, '-' | '.')
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}
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enum Element {
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Class(Span),
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Identifier(Span),
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Attribute(Span, Span),
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Invalid,
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}
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impl<I: Iterator<Item = char>> Iterator for Parser<I> {
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type Item = Element;
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fn next(&mut self) -> Option<Self::Item> {
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loop {
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let (st, span0) = self.step();
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return match st {
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ClassFirst | IdentifierFirst => {
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let (st, span1) = self.step();
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Some(match st {
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Class => Element::Class(span1),
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Identifier => Element::Identifier(span1),
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_ => return Some(Element::Invalid),
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})
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}
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Attribute => {
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let (st, _span1) = self.step();
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match st {
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ValueFirst => {
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let (st, span2) = self.step();
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match st {
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Value => Some(Element::Attribute(span0, span2)),
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ValueQuoted => Some(Element::Attribute(span0, span2.skip(1))),
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Invalid => Some(Element::Invalid),
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_ => panic!("{:?}", st),
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}
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}
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Invalid => Some(Element::Invalid),
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_ => panic!("{:?}", st),
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}
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}
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Comment | Start | Whitespace => continue,
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Done => None,
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Invalid => Some(Element::Invalid),
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_ => panic!("{:?}", st),
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};
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}
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}
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}
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#[cfg(test)]
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mod test {
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macro_rules! test_attr {
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($src:expr $(,$($av:expr),* $(,)?)?) => {
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#[allow(unused)]
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let mut attr =super::Attributes::new();
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attr.parse(&$src);
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let actual = attr.iter().collect::<Vec<_>>();
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let expected = &[$($($av),*,)?];
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assert_eq!(actual, expected, "\n\n{}\n\n", $src);
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};
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}
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#[test]
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fn empty() {
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test_attr!("{}");
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}
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#[test]
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fn class_id() {
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test_attr!(
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"{.some_class #some_id}",
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("class", "some_class"),
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("id", "some_id"),
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);
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}
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#[test]
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fn value_unquoted() {
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test_attr!(
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"{attr0=val0 attr1=val1}",
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("attr0", "val0"),
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("attr1", "val1"),
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);
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}
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#[test]
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fn value_quoted() {
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test_attr!(
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r#"{attr0="val0" attr1="val1"}"#,
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("attr0", "val0"),
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("attr1", "val1"),
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);
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test_attr!(
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r#"{#id .class style="color:red"}"#,
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("id", "id"),
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("class", "class"),
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("style", "color:red")
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);
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}
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#[test]
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fn comment() {
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test_attr!("{%%}");
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test_attr!("{ % abc % }");
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test_attr!(
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"{ .some_class % abc % #some_id}",
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("class", "some_class"),
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("id", "some_id"),
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);
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}
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}
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