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x/deno/core/source_map.rs

A modern runtime for JavaScript and TypeScript.
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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
//! This mod provides functions to remap a `JsError` based on a source map.
use crate::resolve_url;pub use sourcemap::SourceMap;use std::collections::HashMap;use std::str;
pub trait SourceMapGetter { /// Returns the raw source map file. fn get_source_map(&self, file_name: &str) -> Option<Vec<u8>>; fn get_source_line( &self, file_name: &str, line_number: usize, ) -> Option<String>;}
#[derive(Debug, Default)]pub struct SourceMapCache { maps: HashMap<String, Option<SourceMap>>, source_lines: HashMap<(String, i64), Option<String>>,}
pub fn apply_source_map<G: SourceMapGetter + ?Sized>( file_name: String, line_number: i64, column_number: i64, cache: &mut SourceMapCache, getter: &G,) -> (String, i64, i64) { // Lookup expects 0-based line and column numbers, but ours are 1-based. let line_number = line_number - 1; let column_number = column_number - 1;
let default_pos = (file_name.clone(), line_number, column_number); let maybe_source_map = cache.maps.entry(file_name.clone()).or_insert_with(|| { getter .get_source_map(&file_name) .and_then(|raw_source_map| SourceMap::from_slice(&raw_source_map).ok()) }); let (file_name, line_number, column_number) = match maybe_source_map { None => default_pos, Some(source_map) => { match source_map.lookup_token(line_number as u32, column_number as u32) { None => default_pos, Some(token) => match token.get_source() { None => default_pos, Some(source_file_name) => { // The `source_file_name` written by tsc in the source map is // sometimes only the basename of the URL, or has unwanted `<`/`>` // around it. Use the `file_name` we get from V8 if // `source_file_name` does not parse as a URL. let file_name = match resolve_url(source_file_name) { Ok(m) if m.scheme() == "blob" => file_name, Ok(m) => m.to_string(), Err(_) => file_name, }; ( file_name, i64::from(token.get_src_line()), i64::from(token.get_src_col()), ) } }, } } }; (file_name, line_number + 1, column_number + 1)}
const MAX_SOURCE_LINE_LENGTH: usize = 150;
pub fn get_source_line<G: SourceMapGetter + ?Sized>( file_name: &str, line_number: i64, cache: &mut SourceMapCache, getter: &G,) -> Option<String> { cache .source_lines .entry((file_name.to_string(), line_number)) .or_insert_with(|| { // Source lookup expects a 0-based line number, ours are 1-based. let s = getter.get_source_line(file_name, (line_number - 1) as usize); s.filter(|s| s.len() <= MAX_SOURCE_LINE_LENGTH) }) .clone()}