rust/crates/ra_ide_api/src/line_index.rs
2019-06-04 18:05:07 -04:00

281 lines
8.9 KiB
Rust

use crate::TextUnit;
use rustc_hash::FxHashMap;
use superslice::Ext;
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct LineIndex {
pub(crate) newlines: Vec<TextUnit>,
pub(crate) utf16_lines: FxHashMap<u32, Vec<Utf16Char>>,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub struct LineCol {
pub line: u32,
pub col_utf16: u32,
}
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub(crate) struct Utf16Char {
pub(crate) start: TextUnit,
pub(crate) end: TextUnit,
}
impl Utf16Char {
fn len(&self) -> TextUnit {
self.end - self.start
}
}
impl LineIndex {
pub fn new(text: &str) -> LineIndex {
let mut utf16_lines = FxHashMap::default();
let mut utf16_chars = Vec::new();
let mut newlines = vec![0.into()];
let mut curr_row = 0.into();
let mut curr_col = 0.into();
let mut line = 0;
for c in text.chars() {
curr_row += TextUnit::of_char(c);
if c == '\n' {
newlines.push(curr_row);
// Save any utf-16 characters seen in the previous line
if !utf16_chars.is_empty() {
utf16_lines.insert(line, utf16_chars);
utf16_chars = Vec::new();
}
// Prepare for processing the next line
curr_col = 0.into();
line += 1;
continue;
}
let char_len = TextUnit::of_char(c);
if char_len.to_usize() > 1 {
utf16_chars.push(Utf16Char { start: curr_col, end: curr_col + char_len });
}
curr_col += char_len;
}
// Save any utf-16 characters seen in the last line
if !utf16_chars.is_empty() {
utf16_lines.insert(line, utf16_chars);
}
LineIndex { newlines, utf16_lines }
}
pub fn line_col(&self, offset: TextUnit) -> LineCol {
let line = self.newlines.upper_bound(&offset) - 1;
let line_start_offset = self.newlines[line];
let col = offset - line_start_offset;
LineCol { line: line as u32, col_utf16: self.utf8_to_utf16_col(line as u32, col) as u32 }
}
pub fn offset(&self, line_col: LineCol) -> TextUnit {
//FIXME: return Result
let col = self.utf16_to_utf8_col(line_col.line, line_col.col_utf16);
self.newlines[line_col.line as usize] + col
}
fn utf8_to_utf16_col(&self, line: u32, mut col: TextUnit) -> usize {
if let Some(utf16_chars) = self.utf16_lines.get(&line) {
let mut correction = TextUnit::from_usize(0);
for c in utf16_chars {
if col >= c.end {
correction += c.len() - TextUnit::from_usize(1);
} else {
// From here on, all utf16 characters come *after* the character we are mapping,
// so we don't need to take them into account
break;
}
}
col -= correction;
}
col.to_usize()
}
fn utf16_to_utf8_col(&self, line: u32, col: u32) -> TextUnit {
let mut col: TextUnit = col.into();
if let Some(utf16_chars) = self.utf16_lines.get(&line) {
for c in utf16_chars {
if col >= c.start {
col += c.len() - TextUnit::from_usize(1);
} else {
// From here on, all utf16 characters come *after* the character we are mapping,
// so we don't need to take them into account
break;
}
}
}
col
}
}
#[cfg(test)]
/// Simple reference implementation to use in proptests
pub fn to_line_col(text: &str, offset: TextUnit) -> LineCol {
let mut res = LineCol { line: 0, col_utf16: 0 };
for (i, c) in text.char_indices() {
if i + c.len_utf8() > offset.to_usize() {
// if it's an invalid offset, inside a multibyte char
// return as if it was at the start of the char
break;
}
if c == '\n' {
res.line += 1;
res.col_utf16 = 0;
} else {
res.col_utf16 += 1;
}
}
res
}
#[cfg(test)]
mod test_line_index {
use super::*;
use proptest::{prelude::*, proptest};
use ra_text_edit::test_utils::{arb_text, arb_offset};
#[test]
fn test_line_index() {
let text = "hello\nworld";
let index = LineIndex::new(text);
assert_eq!(index.line_col(0.into()), LineCol { line: 0, col_utf16: 0 });
assert_eq!(index.line_col(1.into()), LineCol { line: 0, col_utf16: 1 });
assert_eq!(index.line_col(5.into()), LineCol { line: 0, col_utf16: 5 });
assert_eq!(index.line_col(6.into()), LineCol { line: 1, col_utf16: 0 });
assert_eq!(index.line_col(7.into()), LineCol { line: 1, col_utf16: 1 });
assert_eq!(index.line_col(8.into()), LineCol { line: 1, col_utf16: 2 });
assert_eq!(index.line_col(10.into()), LineCol { line: 1, col_utf16: 4 });
assert_eq!(index.line_col(11.into()), LineCol { line: 1, col_utf16: 5 });
assert_eq!(index.line_col(12.into()), LineCol { line: 1, col_utf16: 6 });
let text = "\nhello\nworld";
let index = LineIndex::new(text);
assert_eq!(index.line_col(0.into()), LineCol { line: 0, col_utf16: 0 });
assert_eq!(index.line_col(1.into()), LineCol { line: 1, col_utf16: 0 });
assert_eq!(index.line_col(2.into()), LineCol { line: 1, col_utf16: 1 });
assert_eq!(index.line_col(6.into()), LineCol { line: 1, col_utf16: 5 });
assert_eq!(index.line_col(7.into()), LineCol { line: 2, col_utf16: 0 });
}
fn arb_text_with_offset() -> BoxedStrategy<(TextUnit, String)> {
arb_text().prop_flat_map(|text| (arb_offset(&text), Just(text))).boxed()
}
fn to_line_col(text: &str, offset: TextUnit) -> LineCol {
let mut res = LineCol { line: 0, col_utf16: 0 };
for (i, c) in text.char_indices() {
if i + c.len_utf8() > offset.to_usize() {
// if it's an invalid offset, inside a multibyte char
// return as if it was at the start of the char
break;
}
if c == '\n' {
res.line += 1;
res.col_utf16 = 0;
} else {
res.col_utf16 += 1;
}
}
res
}
proptest! {
#[test]
fn test_line_index_proptest((offset, text) in arb_text_with_offset()) {
let expected = to_line_col(&text, offset);
let line_index = LineIndex::new(&text);
let actual = line_index.line_col(offset);
assert_eq!(actual, expected);
}
}
}
#[cfg(test)]
mod test_utf8_utf16_conv {
use super::*;
#[test]
fn test_char_len() {
assert_eq!('メ'.len_utf8(), 3);
assert_eq!('メ'.len_utf16(), 1);
}
#[test]
fn test_empty_index() {
let col_index = LineIndex::new(
"
const C: char = 'x';
",
);
assert_eq!(col_index.utf16_lines.len(), 0);
}
#[test]
fn test_single_char() {
let col_index = LineIndex::new(
"
const C: char = 'メ';
",
);
assert_eq!(col_index.utf16_lines.len(), 1);
assert_eq!(col_index.utf16_lines[&1].len(), 1);
assert_eq!(col_index.utf16_lines[&1][0], Utf16Char { start: 17.into(), end: 20.into() });
// UTF-8 to UTF-16, no changes
assert_eq!(col_index.utf8_to_utf16_col(1, 15.into()), 15);
// UTF-8 to UTF-16
assert_eq!(col_index.utf8_to_utf16_col(1, 22.into()), 20);
// UTF-16 to UTF-8, no changes
assert_eq!(col_index.utf16_to_utf8_col(1, 15), TextUnit::from(15));
// UTF-16 to UTF-8
assert_eq!(col_index.utf16_to_utf8_col(1, 19), TextUnit::from(21));
}
#[test]
fn test_string() {
let col_index = LineIndex::new(
"
const C: char = \"メ メ\";
",
);
assert_eq!(col_index.utf16_lines.len(), 1);
assert_eq!(col_index.utf16_lines[&1].len(), 2);
assert_eq!(col_index.utf16_lines[&1][0], Utf16Char { start: 17.into(), end: 20.into() });
assert_eq!(col_index.utf16_lines[&1][1], Utf16Char { start: 21.into(), end: 24.into() });
// UTF-8 to UTF-16
assert_eq!(col_index.utf8_to_utf16_col(1, 15.into()), 15);
assert_eq!(col_index.utf8_to_utf16_col(1, 21.into()), 19);
assert_eq!(col_index.utf8_to_utf16_col(1, 25.into()), 21);
assert!(col_index.utf8_to_utf16_col(2, 15.into()) == 15);
// UTF-16 to UTF-8
assert_eq!(col_index.utf16_to_utf8_col(1, 15), TextUnit::from_usize(15));
assert_eq!(col_index.utf16_to_utf8_col(1, 18), TextUnit::from_usize(20));
assert_eq!(col_index.utf16_to_utf8_col(1, 19), TextUnit::from_usize(23));
assert_eq!(col_index.utf16_to_utf8_col(2, 15), TextUnit::from_usize(15));
}
}