blob: 51df77d95d50114b138a9332810786f80c76191a [file] [log] [blame]
// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
// @dart = 2.9
/// Standalone utility that manages loading source maps for all Dart scripts
/// on the page compiled with DDC.
/// Example JavaScript usage:
/// $dartStackTraceUtility.addLoadedListener(function() {
/// // All Dart source maps are now loaded. It is now safe to start your
/// // Dart application compiled with DDC.
/// dart_library.start('your_dart_application');
/// })
/// If $dartStackTraceUtility is set, the dart:core StackTrace class calls
/// $dartStackTraceUtility.mapper(someJSStackTrace)
/// to apply source maps.
/// This utility can be compiled to JavaScript using Dart2JS while the rest
/// of the application is compiled with DDC or could be compiled with DDC.
library stack_trace_mapper;
import 'package:js/js.dart';
import 'package:path/path.dart' as p;
import 'package:source_maps/source_maps.dart';
import 'package:source_span/source_span.dart';
import 'package:stack_trace/stack_trace.dart';
import 'source_map_stack_trace.dart';
typedef ReadyCallback = void Function();
/// Global object DDC uses to see if a stack trace utility has been registered.
external set dartStackTraceUtility(DartStackTraceUtility value);
external List get rootDirectories;
typedef StackTraceMapper = String Function(String stackTrace);
typedef SourceMapProvider = dynamic Function(String modulePath);
typedef SetSourceMapProvider = void Function(SourceMapProvider);
class DartStackTraceUtility {
external factory DartStackTraceUtility(
{StackTraceMapper mapper, SetSourceMapProvider setSourceMapProvider});
external String _stringify(dynamic json);
/// Source mapping that is waits to parse source maps until they match the uri
/// of a requested source map.
/// This improves startup performance compared to using MappingBundle directly.
/// The unparsed data for the source maps must still be loaded before
/// LazyMapping is used.
class LazyMapping extends Mapping {
final MappingBundle _bundle = MappingBundle();
final SourceMapProvider _provider;
List toJson() => _bundle.toJson();
SourceMapSpan spanFor(int line, int column,
{Map<String, SourceFile> files, String uri}) {
if (uri == null) {
throw ArgumentError.notNull('uri');
if (!_bundle.containsMapping(uri)) {
var rawMap = _provider(uri);
if (rawMap != null) {
var strMap = rawMap is String ? rawMap : _stringify(rawMap);
var mapping = parse(strMap) as SingleMapping;
..targetUrl = uri
..sourceRoot = '${p.dirname(uri)}/';
var span = _bundle.spanFor(line, column, files: files, uri: uri);
// TODO(jacobr): we shouldn't have to filter out invalid sourceUrl entries
// here.
if (span == null || span.start.sourceUrl == null) return null;
var pathSegments = span.start.sourceUrl.pathSegments;
if (pathSegments.isNotEmpty && pathSegments.last == 'null') return null;
return span;
LazyMapping _mapping;
List<String> roots = => '$s').toList();
String mapper(String rawStackTrace) {
if (_mapping == null) {
// This should not happen if the user has waited for the ReadyCallback
// to start the application.
throw StateError('Source maps are not done loading.');
var trace = Trace.parse(rawStackTrace);
return mapStackTrace(_mapping, trace, roots: roots).toString();
void setSourceMapProvider(SourceMapProvider provider) {
_mapping = LazyMapping(provider);
void main() {
// Register with DDC.
dartStackTraceUtility = DartStackTraceUtility(
mapper: allowInterop(mapper),
setSourceMapProvider: allowInterop(setSourceMapProvider));