105 lines
3.1 KiB
Rust
105 lines
3.1 KiB
Rust
use crate::source_map::SourceMap;
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use crate::{BytePos, SourceFile};
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use rustc_data_structures::sync::Lrc;
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#[derive(Clone)]
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struct CacheEntry {
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time_stamp: usize,
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line_number: usize,
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line_start: BytePos,
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line_end: BytePos,
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file: Lrc<SourceFile>,
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file_index: usize,
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}
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#[derive(Clone)]
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pub struct CachingSourceMapView<'sm> {
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source_map: &'sm SourceMap,
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line_cache: [CacheEntry; 3],
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time_stamp: usize,
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}
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impl<'sm> CachingSourceMapView<'sm> {
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pub fn new(source_map: &'sm SourceMap) -> CachingSourceMapView<'sm> {
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let files = source_map.files();
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let first_file = files[0].clone();
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let entry = CacheEntry {
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time_stamp: 0,
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line_number: 0,
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line_start: BytePos(0),
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line_end: BytePos(0),
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file: first_file,
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file_index: 0,
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};
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CachingSourceMapView {
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source_map,
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line_cache: [entry.clone(), entry.clone(), entry],
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time_stamp: 0,
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}
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}
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pub fn byte_pos_to_line_and_col(
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&mut self,
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pos: BytePos,
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) -> Option<(Lrc<SourceFile>, usize, BytePos)> {
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self.time_stamp += 1;
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// Check if the position is in one of the cached lines
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for cache_entry in self.line_cache.iter_mut() {
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if pos >= cache_entry.line_start && pos < cache_entry.line_end {
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cache_entry.time_stamp = self.time_stamp;
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return Some((
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cache_entry.file.clone(),
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cache_entry.line_number,
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pos - cache_entry.line_start,
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));
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}
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}
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// No cache hit ...
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let mut oldest = 0;
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for index in 1..self.line_cache.len() {
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if self.line_cache[index].time_stamp < self.line_cache[oldest].time_stamp {
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oldest = index;
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}
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}
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let cache_entry = &mut self.line_cache[oldest];
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// If the entry doesn't point to the correct file, fix it up
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if pos < cache_entry.file.start_pos || pos >= cache_entry.file.end_pos {
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let file_valid;
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if self.source_map.files().len() > 0 {
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let file_index = self.source_map.lookup_source_file_idx(pos);
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let file = self.source_map.files()[file_index].clone();
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if pos >= file.start_pos && pos < file.end_pos {
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cache_entry.file = file;
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cache_entry.file_index = file_index;
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file_valid = true;
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} else {
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file_valid = false;
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}
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} else {
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file_valid = false;
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}
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if !file_valid {
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return None;
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}
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}
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let line_index = cache_entry.file.lookup_line(pos).unwrap();
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let line_bounds = cache_entry.file.line_bounds(line_index);
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cache_entry.line_number = line_index + 1;
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cache_entry.line_start = line_bounds.0;
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cache_entry.line_end = line_bounds.1;
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cache_entry.time_stamp = self.time_stamp;
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Some((cache_entry.file.clone(), cache_entry.line_number, pos - cache_entry.line_start))
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}
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}
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