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|
use rustc_hash::FxHashSet;
use ra_syntax::{
ast, AstNode, Direction, File,
SyntaxKind::{self, *},
SyntaxNodeRef, TextRange,
};
#[derive(Debug, PartialEq, Eq)]
pub enum FoldKind {
Comment,
Imports,
}
#[derive(Debug)]
pub struct Fold {
pub range: TextRange,
pub kind: FoldKind,
}
pub fn folding_ranges(file: &File) -> Vec<Fold> {
let mut res = vec![];
let mut visited_comments = FxHashSet::default();
for node in file.syntax().descendants() {
// Fold items that span multiple lines
if let Some(kind) = fold_kind(node.kind()) {
if has_newline(node) {
res.push(Fold {
range: node.range(),
kind,
});
}
}
// Also fold groups of comments
if visited_comments.contains(&node) {
continue;
}
if node.kind() == COMMENT {
if let Some(range) = contiguous_range_for_comment(node, &mut visited_comments) {
res.push(Fold {
range,
kind: FoldKind::Comment,
})
}
}
}
res
}
fn fold_kind(kind: SyntaxKind) -> Option<FoldKind> {
match kind {
COMMENT => Some(FoldKind::Comment),
USE_ITEM => Some(FoldKind::Imports),
_ => None,
}
}
fn has_newline(node: SyntaxNodeRef) -> bool {
for descendant in node.descendants() {
if let Some(ws) = ast::Whitespace::cast(descendant) {
if ws.has_newlines() {
return true;
}
} else if let Some(comment) = ast::Comment::cast(descendant) {
if comment.has_newlines() {
return true;
}
}
}
false
}
fn contiguous_range_for_comment<'a>(
first: SyntaxNodeRef<'a>,
visited: &mut FxHashSet<SyntaxNodeRef<'a>>,
) -> Option<TextRange> {
visited.insert(first);
// Only fold comments of the same flavor
let group_flavor = ast::Comment::cast(first)?.flavor();
let mut last = first;
for node in first.siblings(Direction::Next) {
if let Some(ws) = ast::Whitespace::cast(node) {
// There is a blank line, which means the group ends here
if ws.count_newlines_lazy().take(2).count() == 2 {
break;
}
// Ignore whitespace without blank lines
continue;
}
match ast::Comment::cast(node) {
Some(next_comment) if next_comment.flavor() == group_flavor => {
visited.insert(node);
last = node;
}
// The comment group ends because either:
// * An element of a different kind was reached
// * A comment of a different flavor was reached
_ => break,
}
}
if first != last {
Some(TextRange::from_to(
first.range().start(),
last.range().end(),
))
} else {
// The group consists of only one element, therefore it cannot be folded
None
}
}
#[cfg(test)]
mod tests {
use super::*;
use test_utils::extract_ranges;
fn do_check(text: &str, fold_kinds: &[FoldKind]) {
let (ranges, text) = extract_ranges(text);
let file = File::parse(&text);
let folds = folding_ranges(&file);
assert_eq!(folds.len(), ranges.len());
for ((fold, range), fold_kind) in folds
.into_iter()
.zip(ranges.into_iter())
.zip(fold_kinds.into_iter())
{
assert_eq!(fold.range.start(), range.start());
assert_eq!(fold.range.end(), range.end());
assert_eq!(&fold.kind, fold_kind);
}
}
#[test]
fn test_fold_comments() {
let text = r#"
<|>// Hello
// this is a multiline
// comment
//<|>
// But this is not
fn main() {
<|>// We should
// also
// fold
// this one.<|>
<|>//! But this one is different
//! because it has another flavor<|>
<|>/* As does this
multiline comment */<|>
}"#;
let fold_kinds = &[
FoldKind::Comment,
FoldKind::Comment,
FoldKind::Comment,
FoldKind::Comment,
];
do_check(text, fold_kinds);
}
#[test]
fn test_fold_imports() {
let text = r#"
<|>use std::{
str,
vec,
io as iop
};<|>
fn main() {
}"#;
let folds = &[FoldKind::Imports];
do_check(text, folds);
}
}
|
