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denoland-deno/core/source_map.rs
Nayeem Rahman 8b31fc23cd
refactor: Move source map lookups to core (#14274)
The following transformations gradually faced by "JsError" have all been 
moved up front to "JsError::from_v8_exception()": 

- finding the first non-"deno:" source line; 
- moving "JsError::script_resource_name" etc. into the first error stack 
in case of syntax errors; 
- source mapping "JsError::script_resource_name" etc. when wrapping 
the error even though the frame locations are source mapped earlier; 
- removing "JsError::{script_resource_name,line_number,start_column,end_column}"
entirely in favour of "js_error.frames.get(0)". 

We also no longer pass a js-side callback to "core/02_error.js" from cli. 
I avoided doing this on previous occasions because the source map lookups 
were in an awkward place.
2022-04-15 16:08:09 +02:00

99 lines
3.3 KiB
Rust

// 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: Sync + Send {
/// 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>;
}
/// Cached filename lookups. The key can be None if a previous lookup failed to
/// find a SourceMap.
pub type CachedMaps = HashMap<String, Option<SourceMap>>;
pub fn apply_source_map<G: SourceMapGetter + ?Sized>(
file_name: String,
line_number: i64,
column_number: i64,
mappings_map: &mut CachedMaps,
getter: &G,
) -> (String, i64, i64, Option<String>) {
// 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, None);
let maybe_source_map = get_mappings(&file_name, mappings_map, getter);
let (file_name, line_number, column_number, source_line) =
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,
};
let source_line =
if let Some(source_view) = token.get_source_view() {
source_view
.get_line(token.get_src_line())
.map(|s| s.to_string())
} else {
None
};
(
file_name,
i64::from(token.get_src_line()),
i64::from(token.get_src_col()),
source_line,
)
}
},
}
}
};
let source_line = source_line
.or_else(|| getter.get_source_line(&file_name, line_number as usize));
(file_name, line_number + 1, column_number + 1, source_line)
}
fn get_mappings<'a, G: SourceMapGetter + ?Sized>(
file_name: &str,
mappings_map: &'a mut CachedMaps,
getter: &G,
) -> &'a Option<SourceMap> {
mappings_map
.entry(file_name.to_string())
.or_insert_with(|| parse_map_string(file_name, getter))
}
// TODO(kitsonk) parsed source maps should probably be cached in state in
// the module meta data.
fn parse_map_string<G: SourceMapGetter + ?Sized>(
file_name: &str,
getter: &G,
) -> Option<SourceMap> {
getter
.get_source_map(file_name)
.and_then(|raw_source_map| SourceMap::from_slice(&raw_source_map).ok())
}