ide_db/
range_mapper.rs

1//! Maps between ranges in documents.
2
3use std::cmp::Ordering;
4
5use stdx::equal_range_by;
6use syntax::{TextRange, TextSize};
7
8#[derive(Default)]
9pub struct RangeMapper {
10    buf: String,
11    ranges: Vec<(TextRange, Option<TextRange>)>,
12}
13
14impl RangeMapper {
15    pub fn add(&mut self, text: &str, source_range: TextRange) {
16        let len = TextSize::of(text);
17        assert_eq!(len, source_range.len());
18        self.add_impl(text, Some(source_range.start()));
19    }
20
21    pub fn add_unmapped(&mut self, text: &str) {
22        self.add_impl(text, None);
23    }
24
25    fn add_impl(&mut self, text: &str, source: Option<TextSize>) {
26        let len = TextSize::of(text);
27        let target_range = TextRange::at(TextSize::of(&self.buf), len);
28        self.ranges.push((target_range, source.map(|it| TextRange::at(it, len))));
29        self.buf.push_str(text);
30    }
31
32    pub fn take_text(&mut self) -> String {
33        std::mem::take(&mut self.buf)
34    }
35
36    pub fn map_range_up(&self, range: TextRange) -> impl Iterator<Item = TextRange> + '_ {
37        equal_range_by(&self.ranges, |&(r, _)| {
38            if range.is_empty() && r.contains(range.start()) {
39                Ordering::Equal
40            } else {
41                TextRange::ordering(r, range)
42            }
43        })
44        .filter_map(move |i| {
45            let (target_range, source_range) = self.ranges[i];
46            let intersection = target_range.intersect(range).unwrap();
47            let source_range = source_range?;
48            Some(intersection - target_range.start() + source_range.start())
49        })
50    }
51
52    pub fn map_offset_down(&self, offset: TextSize) -> Option<TextSize> {
53        // Using a binary search here is a bit complicated because of the `None` entries.
54        // But the number of lines in fixtures is usually low.
55        let (target_range, source_range) =
56            self.ranges.iter().find_map(|&(target_range, source_range)| {
57                let source_range = source_range?;
58                if !source_range.contains(offset) {
59                    return None;
60                }
61                Some((target_range, source_range))
62            })?;
63        Some(offset - source_range.start() + target_range.start())
64    }
65}
ide_db/range_mapper.rs

ide_db/
range_mapper.rs
