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|
use rustc_hash::FxHashSet;
use ra_syntax::{
ast,
AstNode,
File, TextRange, SyntaxNodeRef,
SyntaxKind,
Direction,
};
#[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 = FxHashSet::default();
for node in file.syntax().descendants() {
if visited.contains(&node) {
continue;
}
if let Some(comment) = ast::Comment::cast(node) {
// Multiline comments (`/* ... */`) can only be folded if they span multiple lines
let range = if let ast::CommentFlavor::Multiline = comment.flavor() {
if comment.text().contains('\n') {
Some(comment.syntax().range())
} else {
None
}
} else {
contiguous_range_for(SyntaxKind::COMMENT, node, &mut visited)
};
range.map(|range| res.push(Fold { range, kind: FoldKind::Comment }));
}
if let SyntaxKind::USE_ITEM = node.kind() {
contiguous_range_for(SyntaxKind::USE_ITEM, node, &mut visited)
.map(|range| res.push(Fold { range, kind: FoldKind::Imports}));
};
}
res
}
fn contiguous_range_for<'a>(
kind: SyntaxKind,
node: SyntaxNodeRef<'a>,
visited: &mut FxHashSet<SyntaxNodeRef<'a>>,
) -> Option<TextRange> {
visited.insert(node);
let left = node;
let mut right = node;
for node in node.siblings(Direction::Next) {
visited.insert(node);
match node.kind() {
SyntaxKind::WHITESPACE if !node.leaf_text().unwrap().as_str().contains("\n\n") => (),
k => {
if k == kind {
right = node
} else {
break;
}
}
}
}
if left != right {
Some(TextRange::from_to(
left.range().start(),
right.range().end(),
))
} else {
None
}
}
#[cfg(test)]
mod tests {
use super::*;
#[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.
}"#;
let file = File::parse(&text);
let folds = folding_ranges(&file);
assert_eq!(folds.len(), 2);
assert_eq!(folds[0].range.start(), 1.into());
assert_eq!(folds[0].range.end(), 46.into());
assert_eq!(folds[0].kind, FoldKind::Comment);
assert_eq!(folds[1].range.start(), 84.into());
assert_eq!(folds[1].range.end(), 137.into());
assert_eq!(folds[1].kind, FoldKind::Comment);
}
#[test]
fn test_fold_imports() {
let text = r#"
use std::str;
use std::vec;
use std::io as iop;
fn main() {
}"#;
let file = File::parse(&text);
let folds = folding_ranges(&file);
assert_eq!(folds.len(), 1);
assert_eq!(folds[0].range.start(), 1.into());
assert_eq!(folds[0].range.end(), 48.into());
assert_eq!(folds[0].kind, FoldKind::Imports);
}
}
|
