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|
//! FIXME: write short doc here
use std::mem;
use parser::{ParseError, TreeSink};
use crate::{
ast,
parsing::Token,
syntax_node::GreenNode,
SyntaxError,
SyntaxKind::{self, *},
SyntaxTreeBuilder, TextRange, TextSize,
};
/// Bridges the parser with our specific syntax tree representation.
///
/// `TextTreeSink` also handles attachment of trivia (whitespace) to nodes.
pub(crate) struct TextTreeSink<'a> {
text: &'a str,
tokens: &'a [Token],
text_pos: TextSize,
token_pos: usize,
state: State,
inner: SyntaxTreeBuilder,
}
enum State {
PendingStart,
Normal,
PendingFinish,
}
impl<'a> TreeSink for TextTreeSink<'a> {
fn token(&mut self, kind: SyntaxKind, n_tokens: u8) {
match mem::replace(&mut self.state, State::Normal) {
State::PendingStart => unreachable!(),
State::PendingFinish => self.inner.finish_node(),
State::Normal => (),
}
self.eat_trivias();
let n_tokens = n_tokens as usize;
let len = self.tokens[self.token_pos..self.token_pos + n_tokens]
.iter()
.map(|it| it.len)
.sum::<TextSize>();
self.do_token(kind, len, n_tokens);
}
fn start_node(&mut self, kind: SyntaxKind) {
match mem::replace(&mut self.state, State::Normal) {
State::PendingStart => {
self.inner.start_node(kind);
// No need to attach trivias to previous node: there is no
// previous node.
return;
}
State::PendingFinish => self.inner.finish_node(),
State::Normal => (),
}
let n_trivias =
self.tokens[self.token_pos..].iter().take_while(|it| it.kind.is_trivia()).count();
let leading_trivias = &self.tokens[self.token_pos..self.token_pos + n_trivias];
let mut trivia_end =
self.text_pos + leading_trivias.iter().map(|it| it.len).sum::<TextSize>();
let n_attached_trivias = {
let leading_trivias = leading_trivias.iter().rev().map(|it| {
let next_end = trivia_end - it.len;
let range = TextRange::new(next_end, trivia_end);
trivia_end = next_end;
(it.kind, &self.text[range])
});
n_attached_trivias(kind, leading_trivias)
};
self.eat_n_trivias(n_trivias - n_attached_trivias);
self.inner.start_node(kind);
self.eat_n_trivias(n_attached_trivias);
}
fn finish_node(&mut self) {
match mem::replace(&mut self.state, State::PendingFinish) {
State::PendingStart => unreachable!(),
State::PendingFinish => self.inner.finish_node(),
State::Normal => (),
}
}
fn error(&mut self, error: ParseError) {
self.inner.error(error, self.text_pos)
}
}
impl<'a> TextTreeSink<'a> {
pub(super) fn new(text: &'a str, tokens: &'a [Token]) -> Self {
Self {
text,
tokens,
text_pos: 0.into(),
token_pos: 0,
state: State::PendingStart,
inner: SyntaxTreeBuilder::default(),
}
}
pub(super) fn finish(mut self) -> (GreenNode, Vec<SyntaxError>) {
match mem::replace(&mut self.state, State::Normal) {
State::PendingFinish => {
self.eat_trivias();
self.inner.finish_node()
}
State::PendingStart | State::Normal => unreachable!(),
}
self.inner.finish_raw()
}
fn eat_trivias(&mut self) {
while let Some(&token) = self.tokens.get(self.token_pos) {
if !token.kind.is_trivia() {
break;
}
self.do_token(token.kind, token.len, 1);
}
}
fn eat_n_trivias(&mut self, n: usize) {
for _ in 0..n {
let token = self.tokens[self.token_pos];
assert!(token.kind.is_trivia());
self.do_token(token.kind, token.len, 1);
}
}
fn do_token(&mut self, kind: SyntaxKind, len: TextSize, n_tokens: usize) {
let range = TextRange::at(self.text_pos, len);
let text = &self.text[range];
self.text_pos += len;
self.token_pos += n_tokens;
self.inner.token(kind, text);
}
}
fn n_attached_trivias<'a>(
kind: SyntaxKind,
trivias: impl Iterator<Item = (SyntaxKind, &'a str)>,
) -> usize {
match kind {
CONST | ENUM | FN | IMPL | MACRO_CALL | MACRO_DEF | MACRO_RULES | MODULE | RECORD_FIELD
| STATIC | STRUCT | TRAIT | TUPLE_FIELD | TYPE_ALIAS | UNION | USE | VARIANT => {
let mut res = 0;
let mut trivias = trivias.enumerate().peekable();
while let Some((i, (kind, text))) = trivias.next() {
match kind {
WHITESPACE if text.contains("\n\n") => {
// we check whether the next token is a doc-comment
// and skip the whitespace in this case
if let Some((COMMENT, peek_text)) = trivias.peek().map(|(_, pair)| pair) {
let comment_kind = ast::CommentKind::from_text(peek_text);
if comment_kind.doc == Some(ast::CommentPlacement::Outer) {
continue;
}
}
break;
}
COMMENT => {
let comment_kind = ast::CommentKind::from_text(text);
if comment_kind.doc == Some(ast::CommentPlacement::Inner) {
break;
}
res = i + 1;
}
_ => (),
}
}
res
}
_ => 0,
}
}
|
