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use tree_sitter::Node;
use crate::{Rope, Syntax};
const MAX_PLAINTEXT_SCAN: usize = 10000;
// Limit matching pairs to only ( ) { } [ ] < > ' ' " "
const PAIRS: &[(char, char)] = &[
('(', ')'),
('{', '}'),
('[', ']'),
('<', '>'),
('\'', '\''),
('\"', '\"'),
];
/// Returns the position of the matching bracket under cursor.
///
/// If the cursor is on the opening bracket, the position of
/// the closing bracket is returned. If the cursor on the closing
/// bracket, the position of the opening bracket is returned.
///
/// If the cursor is not on a bracket, `None` is returned.
///
/// If no matching bracket is found, `None` is returned.
#[must_use]
pub fn find_matching_bracket(syntax: &Syntax, doc: &Rope, pos: usize) -> Option<usize> {
if pos >= doc.len_chars() || !is_valid_bracket(doc.char(pos)) {
return None;
}
find_pair(syntax, doc, pos, false)
}
// Returns the position of the bracket that is closing the current scope.
//
// If the cursor is on an opening or closing bracket, the function
// behaves equivalent to [`find_matching_bracket`].
//
// If the cursor position is within a scope, the function searches
// for the surrounding scope that is surrounded by brackets and
// returns the position of the closing bracket for that scope.
//
// If no surrounding scope is found, the function returns `None`.
#[must_use]
pub fn find_matching_bracket_fuzzy(syntax: &Syntax, doc: &Rope, pos: usize) -> Option<usize> {
find_pair(syntax, doc, pos, true)
}
fn find_pair(syntax: &Syntax, doc: &Rope, pos: usize, traverse_parents: bool) -> Option<usize> {
let tree = syntax.tree();
let pos = doc.char_to_byte(pos);
let mut node = tree.root_node().named_descendant_for_byte_range(pos, pos)?;
loop {
let (start_byte, end_byte) = surrounding_bytes(doc, &node)?;
let (start_char, end_char) = (doc.byte_to_char(start_byte), doc.byte_to_char(end_byte));
if is_valid_pair(doc, start_char, end_char) {
if end_byte == pos {
return Some(start_char);
}
// We return the end char if the cursor is either on the start char
// or at some arbitrary position between start and end char.
return Some(end_char);
}
if traverse_parents {
node = node.parent()?;
} else {
return None;
}
}
}
/// Returns the position of the matching bracket under cursor.
/// This function works on plain text and ignores tree-sitter grammar.
/// The search is limited to `MAX_PLAINTEXT_SCAN` characters
///
/// If the cursor is on the opening bracket, the position of
/// the closing bracket is returned. If the cursor on the closing
/// bracket, the position of the opening bracket is returned.
///
/// If the cursor is not on a bracket, `None` is returned.
///
/// If no matching bracket is found, `None` is returned.
#[must_use]
pub fn find_matching_bracket_current_line_plaintext(
doc: &Rope,
cursor_pos: usize,
) -> Option<usize> {
// Don't do anything when the cursor is not on top of a bracket.
let bracket = doc.char(cursor_pos);
if !is_valid_bracket(bracket) {
return None;
}
// Determine the direction of the matching.
let is_fwd = is_forward_bracket(bracket);
let chars_iter = if is_fwd {
doc.chars_at(cursor_pos + 1)
} else {
doc.chars_at(cursor_pos).reversed()
};
let mut open_cnt = 1;
for (i, candidate) in chars_iter.take(MAX_PLAINTEXT_SCAN).enumerate() {
if candidate == bracket {
open_cnt += 1;
} else if is_valid_pair(
doc,
if is_fwd {
cursor_pos
} else {
cursor_pos - i - 1
},
if is_fwd {
cursor_pos + i + 1
} else {
cursor_pos
},
) {
// Return when all pending brackets have been closed.
if open_cnt == 1 {
return Some(if is_fwd {
cursor_pos + i + 1
} else {
cursor_pos - i - 1
});
}
open_cnt -= 1;
}
}
None
}
fn is_valid_bracket(c: char) -> bool {
PAIRS.iter().any(|(l, r)| *l == c || *r == c)
}
fn is_forward_bracket(c: char) -> bool {
PAIRS.iter().any(|(l, _)| *l == c)
}
fn is_valid_pair(doc: &Rope, start_char: usize, end_char: usize) -> bool {
PAIRS.contains(&(doc.char(start_char), doc.char(end_char)))
}
fn surrounding_bytes(doc: &Rope, node: &Node) -> Option<(usize, usize)> {
let len = doc.len_bytes();
let start_byte = node.start_byte();
let end_byte = node.end_byte().saturating_sub(1);
if start_byte >= len || end_byte >= len {
return None;
}
Some((start_byte, end_byte))
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_find_matching_bracket_current_line_plaintext() {
let assert = |input: &str, pos, expected| {
let input = &Rope::from(input);
let actual = find_matching_bracket_current_line_plaintext(input, pos);
assert_eq!(expected, actual.unwrap());
let actual = find_matching_bracket_current_line_plaintext(input, expected);
assert_eq!(pos, actual.unwrap(), "expected symmetrical behaviour");
};
assert("(hello)", 0, 6);
assert("((hello))", 0, 8);
assert("((hello))", 1, 7);
assert("(((hello)))", 2, 8);
assert("key: ${value}", 6, 12);
assert("key: ${value} # (some comment)", 16, 29);
assert("(paren (paren {bracket}))", 0, 24);
assert("(paren (paren {bracket}))", 7, 23);
assert("(paren (paren {bracket}))", 14, 22);
assert("(prev line\n ) (middle) ( \n next line)", 0, 12);
assert("(prev line\n ) (middle) ( \n next line)", 14, 21);
assert("(prev line\n ) (middle) ( \n next line)", 23, 36);
}
}
|
