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use crate::source_map::SourceMap;
use crate::{BytePos, SourceFile, SpanData};
use rustc_data_structures::sync::Lrc;
use std::ops::Range;
#[derive(Clone)]
struct CacheEntry {
time_stamp: usize,
line_number: usize,
line: Range<BytePos>,
file: Lrc<SourceFile>,
file_index: usize,
}
impl CacheEntry {
#[inline]
fn update(
&mut self,
new_file_and_idx: Option<(Lrc<SourceFile>, usize)>,
pos: BytePos,
time_stamp: usize,
) {
if let Some((file, file_idx)) = new_file_and_idx {
self.file = file;
self.file_index = file_idx;
}
let line_index = self.file.lookup_line(pos).unwrap();
let line_bounds = self.file.line_bounds(line_index);
self.line_number = line_index + 1;
self.line = line_bounds;
self.touch(time_stamp);
}
#[inline]
fn touch(&mut self, time_stamp: usize) {
self.time_stamp = time_stamp;
}
}
#[derive(Clone)]
pub struct CachingSourceMapView<'sm> {
source_map: &'sm SourceMap,
line_cache: [CacheEntry; 3],
time_stamp: usize,
}
impl<'sm> CachingSourceMapView<'sm> {
pub fn new(source_map: &'sm SourceMap) -> CachingSourceMapView<'sm> {
let files = source_map.files();
let first_file = files[0].clone();
let entry = CacheEntry {
time_stamp: 0,
line_number: 0,
line: BytePos(0)..BytePos(0),
file: first_file,
file_index: 0,
};
CachingSourceMapView {
source_map,
line_cache: [entry.clone(), entry.clone(), entry],
time_stamp: 0,
}
}
pub fn byte_pos_to_line_and_col(
&mut self,
pos: BytePos,
) -> Option<(Lrc<SourceFile>, usize, BytePos)> {
self.time_stamp += 1;
let cache_idx = self.cache_entry_index(pos);
if cache_idx != -1 {
let cache_entry = &mut self.line_cache[cache_idx as usize];
cache_entry.touch(self.time_stamp);
return Some((
cache_entry.file.clone(),
cache_entry.line_number,
pos - cache_entry.line.start,
));
}
let oldest = self.oldest_cache_entry_index();
let new_file_and_idx = if !file_contains(&self.line_cache[oldest].file, pos) {
Some(self.file_for_position(pos)?)
} else {
None
};
let cache_entry = &mut self.line_cache[oldest];
cache_entry.update(new_file_and_idx, pos, self.time_stamp);
Some((cache_entry.file.clone(), cache_entry.line_number, pos - cache_entry.line.start))
}
pub fn span_data_to_lines_and_cols(
&mut self,
span_data: &SpanData,
) -> Option<(Lrc<SourceFile>, usize, BytePos, usize, BytePos)> {
self.time_stamp += 1;
let lo_cache_idx = self.cache_entry_index(span_data.lo);
let hi_cache_idx = self.cache_entry_index(span_data.hi);
if lo_cache_idx != -1 && hi_cache_idx != -1 {
let result = {
let lo = &self.line_cache[lo_cache_idx as usize];
let hi = &self.line_cache[hi_cache_idx as usize];
if lo.file_index != hi.file_index {
return None;
}
(
lo.file.clone(),
lo.line_number,
span_data.lo - lo.line.start,
hi.line_number,
span_data.hi - hi.line.start,
)
};
self.line_cache[lo_cache_idx as usize].touch(self.time_stamp);
self.line_cache[hi_cache_idx as usize].touch(self.time_stamp);
return Some(result);
}
let oldest = if lo_cache_idx != -1 || hi_cache_idx != -1 {
let avoid_idx = if lo_cache_idx != -1 { lo_cache_idx } else { hi_cache_idx };
self.oldest_cache_entry_index_avoid(avoid_idx as usize)
} else {
self.oldest_cache_entry_index()
};
let new_file_and_idx = if !file_contains(&self.line_cache[oldest].file, span_data.lo) {
let new_file_and_idx = self.file_for_position(span_data.lo)?;
if !file_contains(&new_file_and_idx.0, span_data.hi) {
return None;
}
Some(new_file_and_idx)
} else {
let file = &self.line_cache[oldest].file;
if !file_contains(&file, span_data.hi) {
return None;
}
None
};
let (lo_idx, hi_idx) = match (lo_cache_idx, hi_cache_idx) {
(-1, -1) => {
let lo = &mut self.line_cache[oldest];
lo.update(new_file_and_idx, span_data.lo, self.time_stamp);
if !lo.line.contains(&span_data.hi) {
let new_file_and_idx = Some((lo.file.clone(), lo.file_index));
let next_oldest = self.oldest_cache_entry_index_avoid(oldest);
let hi = &mut self.line_cache[next_oldest];
hi.update(new_file_and_idx, span_data.hi, self.time_stamp);
(oldest, next_oldest)
} else {
(oldest, oldest)
}
}
(-1, _) => {
let lo = &mut self.line_cache[oldest];
lo.update(new_file_and_idx, span_data.lo, self.time_stamp);
let hi = &mut self.line_cache[hi_cache_idx as usize];
hi.touch(self.time_stamp);
(oldest, hi_cache_idx as usize)
}
(_, -1) => {
let hi = &mut self.line_cache[oldest];
hi.update(new_file_and_idx, span_data.hi, self.time_stamp);
let lo = &mut self.line_cache[lo_cache_idx as usize];
lo.touch(self.time_stamp);
(lo_cache_idx as usize, oldest)
}
_ => {
panic!();
}
};
let lo = &self.line_cache[lo_idx];
let hi = &self.line_cache[hi_idx];
assert!(span_data.lo >= lo.line.start);
assert!(span_data.lo <= lo.line.end);
assert!(span_data.hi >= hi.line.start);
assert!(span_data.hi <= hi.line.end);
assert!(lo.file.contains(span_data.lo));
assert!(lo.file.contains(span_data.hi));
assert_eq!(lo.file_index, hi.file_index);
Some((
lo.file.clone(),
lo.line_number,
span_data.lo - lo.line.start,
hi.line_number,
span_data.hi - hi.line.start,
))
}
fn cache_entry_index(&self, pos: BytePos) -> isize {
for (idx, cache_entry) in self.line_cache.iter().enumerate() {
if cache_entry.line.contains(&pos) {
return idx as isize;
}
}
-1
}
fn oldest_cache_entry_index(&self) -> usize {
let mut oldest = 0;
for idx in 1..self.line_cache.len() {
if self.line_cache[idx].time_stamp < self.line_cache[oldest].time_stamp {
oldest = idx;
}
}
oldest
}
fn oldest_cache_entry_index_avoid(&self, avoid_idx: usize) -> usize {
let mut oldest = if avoid_idx != 0 { 0 } else { 1 };
for idx in 0..self.line_cache.len() {
if idx != avoid_idx
&& self.line_cache[idx].time_stamp < self.line_cache[oldest].time_stamp
{
oldest = idx;
}
}
oldest
}
fn file_for_position(&self, pos: BytePos) -> Option<(Lrc<SourceFile>, usize)> {
if !self.source_map.files().is_empty() {
let file_idx = self.source_map.lookup_source_file_idx(pos);
let file = &self.source_map.files()[file_idx];
if file_contains(file, pos) {
return Some((file.clone(), file_idx));
}
}
None
}
}
#[inline]
fn file_contains(file: &SourceFile, pos: BytePos) -> bool {
file.contains(pos) && !file.is_empty()
}