46 lines
1.4 KiB
Rust
46 lines
1.4 KiB
Rust
use ra_syntax::{
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SourceFile, TextUnit,
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algo::find_token_at_offset,
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SyntaxKind::{self},
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ast::AstNode,
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T
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};
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pub fn matching_brace(file: &SourceFile, offset: TextUnit) -> Option<TextUnit> {
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const BRACES: &[SyntaxKind] =
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&[T!['{'], T!['}'], T!['['], T![']'], T!['('], T![')'], T![<], T![>]];
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let (brace_node, brace_idx) = find_token_at_offset(file.syntax(), offset)
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.filter_map(|node| {
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let idx = BRACES.iter().position(|&brace| brace == node.kind())?;
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Some((node, idx))
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})
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.next()?;
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let parent = brace_node.parent();
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let matching_kind = BRACES[brace_idx ^ 1];
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let matching_node = parent.children_with_tokens().find(|node| node.kind() == matching_kind)?;
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Some(matching_node.range().start())
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}
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#[cfg(test)]
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mod tests {
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use test_utils::{add_cursor, assert_eq_text, extract_offset};
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use super::*;
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#[test]
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fn test_matching_brace() {
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fn do_check(before: &str, after: &str) {
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let (pos, before) = extract_offset(before);
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let file = SourceFile::parse(&before).tree;
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let new_pos = match matching_brace(&file, pos) {
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None => pos,
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Some(pos) => pos,
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};
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let actual = add_cursor(&before, new_pos);
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assert_eq_text!(after, &actual);
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}
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do_check("struct Foo { a: i32, }<|>", "struct Foo <|>{ a: i32, }");
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}
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}
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