blob: 091e220c5c13d57133fff267aa8ff153d93506c9 [file] [log] [blame]
// Copyright (c) 2013, 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.
/// Contains a builder object useful for creating source maps programatically.
library source_maps.builder;
// TODO(sigmund): add a builder for multi-section mappings.
import 'dart:convert';
import 'package:source_span/source_span.dart';
import 'parser.dart';
import 'src/source_map_span.dart';
/// Builds a source map given a set of mappings.
class SourceMapBuilder {
final List<Entry> _entries = <Entry>[];
/// Adds an entry mapping the [targetOffset] to [source].
void addFromOffset(SourceLocation source, SourceFile targetFile,
int targetOffset, String identifier) {
if (targetFile == null) {
throw new ArgumentError('targetFile cannot be null');
new Entry(source, targetFile.location(targetOffset), identifier));
/// Adds an entry mapping [target] to [source].
/// If [isIdentifier] is true or if [target] is a [SourceMapSpan] with
/// `isIdentifier` set to true, this entry is considered to represent an
/// identifier whose value will be stored in the source map. [isIdenfier]
/// takes precedence over [target]'s `isIdentifier` value.
void addSpan(SourceSpan source, SourceSpan target, {bool isIdentifier}) {
if (isIdentifier == null) {
isIdentifier = source is SourceMapSpan ? source.isIdentifier : false;
var name = isIdentifier ? source.text : null;
_entries.add(new Entry(source.start, target.start, name));
/// Adds an entry mapping [target] to [source].
void addLocation(SourceLocation source, SourceLocation target,
String identifier) {
_entries.add(new Entry(source, target, identifier));
/// Encodes all mappings added to this builder as a json map.
Map build(String fileUrl) {
return new SingleMapping.fromEntries(this._entries, fileUrl).toJson();
/// Encodes all mappings added to this builder as a json string.
String toJson(String fileUrl) => JSON.encode(build(fileUrl));
/// An entry in the source map builder.
class Entry implements Comparable {
/// Span denoting the original location in the input source file
final SourceLocation source;
/// Span indicating the corresponding location in the target file.
final SourceLocation target;
/// An identifier name, when this location is the start of an identifier.
final String identifierName;
/// Creates a new [Entry] mapping [target] to [source].
Entry(this.source,, this.identifierName);
/// Implements [Comparable] to ensure that entries are ordered by their
/// location in the target file. We sort primarily by the target offset
/// because source map files are encoded by printing each mapping in order as
/// they appear in the target file.
int compareTo(Entry other) {
int res = target.compareTo(;
if (res != 0) return res;
res = source.sourceUrl.toString().compareTo(
if (res != 0) return res;
return source.compareTo(other.source);