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|
use libsyntax2::{
File, TextRange, SyntaxNodeRef, TextUnit,
SyntaxKind::*,
algo::{find_leaf_at_offset, LeafAtOffset, find_covering_node, ancestors, Direction, siblings},
};
pub fn extend_selection(file: &File, range: TextRange) -> Option<TextRange> {
let syntax = file.syntax();
extend(syntax.borrowed(), range)
}
pub(crate) fn extend(root: SyntaxNodeRef, range: TextRange) -> Option<TextRange> {
if range.is_empty() {
let offset = range.start();
let mut leaves = find_leaf_at_offset(root, offset);
if leaves.clone().all(|it| it.kind() == WHITESPACE) {
return Some(extend_ws(root, leaves.next()?, offset));
}
let leaf = match leaves {
LeafAtOffset::None => return None,
LeafAtOffset::Single(l) => l,
LeafAtOffset::Between(l, r) => pick_best(l, r),
};
return Some(leaf.range());
};
let node = find_covering_node(root, range);
if node.kind() == COMMENT && range == node.range() {
if let Some(range) = extend_comments(node) {
return Some(range);
}
}
match ancestors(node).skip_while(|n| n.range() == range).next() {
None => None,
Some(parent) => Some(parent.range()),
}
}
fn extend_ws(root: SyntaxNodeRef, ws: SyntaxNodeRef, offset: TextUnit) -> TextRange {
let ws_text = ws.leaf_text().unwrap();
let suffix = TextRange::from_to(offset, ws.range().end()) - ws.range().start();
let prefix = TextRange::from_to(ws.range().start(), offset) - ws.range().start();
let ws_suffix = &ws_text.as_str()[suffix];
let ws_prefix = &ws_text.as_str()[prefix];
if ws_text.contains("\n") && !ws_suffix.contains("\n") {
if let Some(node) = ws.next_sibling() {
let start = match ws_prefix.rfind('\n') {
Some(idx) => ws.range().start() + TextUnit::from((idx + 1) as u32),
None => node.range().start()
};
let end = if root.text().char_at(node.range().end()) == Some('\n') {
node.range().end() + TextUnit::of_char('\n')
} else {
node.range().end()
};
return TextRange::from_to(start, end);
}
}
ws.range()
}
fn pick_best<'a>(l: SyntaxNodeRef<'a>, r: SyntaxNodeRef<'a>) -> SyntaxNodeRef<'a> {
return if priority(r) > priority(l) { r } else { l };
fn priority(n: SyntaxNodeRef) -> usize {
match n.kind() {
WHITESPACE => 0,
IDENT | SELF_KW | SUPER_KW | CRATE_KW => 2,
_ => 1,
}
}
}
fn extend_comments(node: SyntaxNodeRef) -> Option<TextRange> {
let left = adj_comments(node, Direction::Backward);
let right = adj_comments(node, Direction::Forward);
if left != right {
Some(TextRange::from_to(
left.range().start(),
right.range().end(),
))
} else {
None
}
}
fn adj_comments(node: SyntaxNodeRef, dir: Direction) -> SyntaxNodeRef {
let mut res = node;
for node in siblings(node, dir) {
match node.kind() {
COMMENT => res = node,
WHITESPACE if !node.leaf_text().unwrap().as_str().contains("\n\n") => (),
_ => break
}
}
res
}
#[cfg(test)]
mod tests {
use super::*;
use test_utils::extract_offset;
fn do_check(before: &str, afters: &[&str]) {
let (cursor, before) = extract_offset(before);
let file = File::parse(&before);
let mut range = TextRange::offset_len(cursor, 0.into());
for &after in afters {
range = extend_selection(&file, range)
.unwrap();
let actual = &before[range];
assert_eq!(after, actual);
}
}
#[test]
fn test_extend_selection_arith() {
do_check(
r#"fn foo() { <|>1 + 1 }"#,
&["1", "1 + 1", "{ 1 + 1 }"],
);
}
#[test]
fn test_extend_selection_start_of_the_lind() {
do_check(
r#"
impl S {
<|> fn foo() {
}
}"#,
&[" fn foo() {\n\n }\n"]
);
}
#[test]
fn test_extend_selection_comments() {
do_check(
r#"
fn bar(){}
// fn foo() {
// 1 + <|>1
// }
// fn foo(){}
"#,
&["// 1 + 1", "// fn foo() {\n// 1 + 1\n// }"]
);
}
#[test]
fn test_extend_selection_prefer_idents() {
do_check(
r#"
fn main() { foo<|>+bar;}
"#,
&["foo", "foo+bar"]
);
do_check(
r#"
fn main() { foo+<|>bar;}
"#,
&["bar", "foo+bar"]
);
}
}
|
