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use std::mem;
use crate::{
ParserError,
SyntaxKind::{self, *},
TreeSink,
};
#[derive(Debug, Clone)]
pub enum Event {
Start {
kind: SyntaxKind,
start: usize,
forward_parent: Option<u32>,
},
Finish {
end: usize,
},
Token {
kind: SyntaxKind,
},
Error {
err: ParserError,
},
}
impl Event {
pub fn tombstone(start: usize) -> Self {
Event::Start {
kind: TOMBSTONE,
forward_parent: None,
start,
}
}
}
#[inline]
pub fn process(sink: &mut dyn TreeSink, mut events: Vec<Event>) {
let mut forward_parents = Vec::new();
for i in 0..events.len() {
match mem::replace(&mut events[i], Event::tombstone(0)) {
Event::Start {
kind: TOMBSTONE, ..
} => (),
Event::Start {
kind,
forward_parent,
..
} => {
forward_parents.push(kind);
let mut idx = i;
let mut fp = forward_parent;
while let Some(fwd) = fp {
idx += fwd as usize;
fp = match mem::replace(&mut events[idx], Event::tombstone(0)) {
Event::Start {
kind,
forward_parent,
..
} => {
if kind != TOMBSTONE {
forward_parents.push(kind);
}
forward_parent
}
_ => unreachable!(),
};
}
for kind in forward_parents.drain(..).rev() {
sink.start_node(kind);
}
}
Event::Finish { .. } => sink.finish_node(),
Event::Token { kind } => {
sink.token(kind);
}
Event::Error { err } => sink.error(err),
}
}
}