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 { let syntax = file.syntax(); extend(syntax.borrowed(), range) } pub(crate) fn extend(root: SyntaxNodeRef, range: TextRange) -> Option { 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 { 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"] ); } }