blob: 767ab1fe8d7d00e265f7d08c7d106e1d165da33e [file] [log] [blame]
#!/usr/bin/env dart
// Copyright (c) 2015, 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.
/// Command line tool to merge the SDK libraries and our patch files.
/// This is currently designed as an offline tool, but we could automate it.
import 'dart:io';
import 'dart:isolate' show RawReceivePort;
import 'dart:async';
import 'dart:math' as math;
import 'dart:convert' show JSON;
import 'package:analyzer/analyzer.dart';
import 'package:analyzer/src/generated/sdk.dart';
import 'package:path/path.dart' as path;
import 'package:front_end/front_end.dart';
import 'package:front_end/src/base/processed_options.dart';
import 'package:front_end/src/kernel_generator_impl.dart';
import 'package:front_end/src/fasta/util/relativize.dart' show relativizeUri;
import 'package:front_end/src/fasta/get_dependencies.dart' show getDependencies;
import 'package:front_end/src/fasta/kernel/utils.dart' show writeProgramToFile;
import 'package:kernel/target/targets.dart';
import 'package:kernel/target/vm.dart' show VmTarget;
import 'package:kernel/target/flutter.dart' show FlutterTarget;
import 'package:compiler/src/kernel/dart2js_target.dart' show Dart2jsTarget;
/// Set of input files that were read by this script to generate patched SDK.
/// We will dump it out into the depfile for ninja to use.
/// For more information see GN and Ninja references:
final deps = new Set<Uri>();
/// Create [File] object from the given path and register it as a dependency.
File getInputFile(String path, {canBeMissing: false}) {
final file = new File(path);
if (!file.existsSync()) {
if (!canBeMissing)
throw "patch_sdk.dart expects all inputs to exist, missing: $path";
return null;
return file;
/// Read the given file synchronously as a string and register this path as
/// a dependency.
String readInputFile(String path, {canBeMissing: false}) =>
getInputFile(path, canBeMissing: canBeMissing)?.readAsStringSync();
Future main(List<String> argv) async {
var port = new RawReceivePort();
try {
await _main(argv);
} finally {
void usage(String mode) {
var base = path.fromUri(Platform.script);
final self = path.relative(base);
print('Usage: $self $mode SDK_DIR PATCH_DIR OUTPUT_DIR PACKAGES');
final repositoryDir = path.relative(path.dirname(path.dirname(base)));
final sdkExample = path.relative(path.join(repositoryDir, 'sdk'));
final patchExample = path.relative(
path.join(repositoryDir, 'out', 'DebugX64', 'obj', 'gen', 'patch'));
final outExample = path.relative(
path.join(repositoryDir, 'out', 'DebugX64', 'obj', 'gen', 'patched_sdk'));
final packagesExample = path.relative(path.join(repositoryDir, '.packages'));
print('For example:');
print('\$ $self vm $sdkExample $patchExample $outExample $packagesExample');
const validModes = const [
String mode;
bool get forVm => mode == 'vm';
bool get forFlutter => mode == 'flutter' || mode == 'flutter_release';
bool get forFlutterRelease => mode == 'flutter_release';
bool get forDart2js => mode == 'dart2js';
bool get forVipunen => mode == 'vipunen';
Future _main(List<String> argv) async {
if (argv.isEmpty) usage('[${validModes.join('|')}]');
mode = argv.first;
if (!validModes.contains(mode)) usage('[${validModes.join('|')}]');
if (argv.length != 5) usage(mode);
var input = argv[1];
var sdkLibIn = path.join(input, 'lib');
var patchIn = argv[2];
var outDir = argv[3];
var outDirUri = Uri.base.resolveUri(new;
var sdkOut = path.join(outDir, 'lib');
var packagesFile = argv[4];
await new Directory.fromUri(outDirUri).delete(recursive: true);
// Parse libraries.dart
var libContents = readInputFile(path.join(
sdkLibIn, '_internal', 'sdk_library_metadata', 'lib', 'libraries.dart'));
libContents = _updateLibraryMetadata(sdkOut, libContents);
var sdkLibraries = _getSdkLibraries(libContents);
var locations = <String, Map<String, String>>{};
// Enumerate core libraries and apply patches
for (SdkLibrary library in sdkLibraries) {
if (forDart2js && library.isVmLibrary) continue;
if (!forDart2js && library.isDart2JsLibrary) continue;
_applyPatch(library, sdkLibIn, patchIn, sdkOut, locations);
_copyExtraLibraries(sdkOut, locations);
final Uri platform = outDirUri.resolve('platform.dill.tmp');
final Uri librariesJson = outDirUri.resolve("lib/libraries.json");
final Uri packages = Uri.base.resolveUri(new Uri.file(packagesFile));
TargetFlags flags = new TargetFlags();
Target target;
switch (mode) {
case 'vm':
case 'vipunen':
target = new VmTarget(flags);
case 'flutter':
case 'flutter_release':
target = new FlutterTarget(flags);
case 'dart2js':
target = new Dart2jsTarget(flags);
throw "Unknown mode: $mode";
await _writeSync(
(forVipunen ? "vm" : mode): {"libraries": locations}
await compilePlatform(outDirUri, target, packages, platform);
// We generate a dependency file for GN to properly regenerate the patched sdk
// folder, outline.dill and platform.dill files when necessary: either when
// the sdk sources change or when this script is updated. In particular:
// - sdk changes: we track the actual sources we are compiling. If we are
// building the dart2js sdk, this includes the dart2js-specific patch
// files.
// These files are tracked by [deps] and passed below to [writeDepsFile] in
// the extraDependencies argument.
// - script updates: we track this script file and any code it imports (even
// sdk libraries). Note that this script runs on the standalone VM, so any
// sdk library used by this script indirectly depends on a VM-specific
// patch file.
// These set of files is discovered by `getDependencies` below, and the
// [platformForDeps] is always the VM-specific `platform.dill` file.
var platformForDeps = platform;
var sdkDir = outDirUri;
if (forDart2js || forFlutter) {
// Note: this fails if `$root_out_dir/vm_platform.dill` doesn't exist. The
// target //utils/compiler:patched_dart2js_sdk depends on
// //runtime/vm:kernel_platform_files to ensure this file exists.
platformForDeps = outDirUri.resolve('../vm_platform.dill');
sdkDir = null;
deps.addAll(await getDependencies(Platform.script,
sdk: sdkDir, packages: packages, platform: platformForDeps));
await writeDepsFile(
librariesJson, Uri.base.resolveUri(new Uri.file("$outDir.d")), deps);
/// Generates an outline.dill and platform.dill file containing the result of
/// compiling a platform's SDK.
/// Returns a list of dependencies read by the compiler. This list can be used
/// to create GN dependency files.
Future<List<Uri>> compilePlatform(
Uri patchedSdk, Target target, Uri packages, Uri output) async {
var options = new CompilerOptions()
..setExitCodeOnProblem = true
..strongMode = forVipunen
..compileSdk = true
..sdkRoot = patchedSdk
..packagesFileUri = packages
..chaseDependencies = true = target;
var inputs = [Uri.parse('dart:core')];
if (forFlutter && !forFlutterRelease) {
[Uri.parse('dart:vmservice_sky'), Uri.parse('dart:diagnostic_server')]);
var result = await generateKernel(
new ProcessedOptions(
// TODO(sigmund): pass all sdk libraries needed here, and make this
// hermetic.
buildSummary: true,
buildProgram: true);
await writeProgramToFile(result.program, output);
return result.deps;
Future writeDepsFile(
Uri output, Uri depsFile, Iterable<Uri> allDependencies) async {
if (allDependencies.isEmpty) return;
String toRelativeFilePath(Uri uri) {
// Ninja expects to find file names relative to the current working
// directory. We've tried making them relative to the deps file, but that
// doesn't work for downstream projects. Making them absolute also
// doesn't work.
// We can test if it works by running ninja twice, for example:
// ninja -C xcodebuild/ReleaseX64 runtime_kernel -d explain
// ninja -C xcodebuild/ReleaseX64 runtime_kernel -d explain
// The second time, ninja should say:
// ninja: Entering directory `xcodebuild/ReleaseX64'
// ninja: no work to do.
// It's broken if it says something like this:
// ninja explain: expected depfile 'patched_sdk.d' to mention
// 'patched_sdk/platform.dill', got
// '/.../xcodebuild/ReleaseX64/patched_sdk/platform.dill'
return Uri.parse(relativizeUri(uri, base: Uri.base)).toFilePath();
StringBuffer sb = new StringBuffer();
for (Uri uri in allDependencies) {
sb.write(" ");
await new File.fromUri(depsFile).writeAsString("$sb");
/// Updates the contents of
/// sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart to include
/// declarations for vm internal libraries.
String _updateLibraryMetadata(String sdkOut, String libContents) {
if (!forVm && !forFlutter && !forVipunen) return libContents;
var extraLibraries = new StringBuffer();
"_builtin": const LibraryInfo(
categories: "Client,Server",
implementation: true,
documented: false,
platforms: VM_PLATFORM),
"profiler": const LibraryInfo(
maturity: Maturity.DEPRECATED,
documented: false),
if (forFlutter) {
"ui": const LibraryInfo(
categories: "Client,Server",
implementation: true,
documented: false,
platforms: VM_PLATFORM),
if (!forFlutterRelease) {
// vmservice should be present unless we build release flavor of Flutter.
"_vmservice": const LibraryInfo(
categories: "Client,Server",
implementation: true,
documented: false,
platforms: VM_PLATFORM),
"vmservice_sky": const LibraryInfo(
categories: "Client,Server",
implementation: true,
documented: false,
platforms: VM_PLATFORM),
"diagnostic_server": const LibraryInfo(
categories: "Client,Server",
implementation: true,
documented: false,
platforms: VM_PLATFORM),
libContents = libContents.replaceAll(
' libraries = const {', ' libraries = const { $extraLibraries');
sdkOut, '_internal', 'sdk_library_metadata', 'lib', 'libraries.dart'),
return libContents;
/// Copy internal libraries that are developed outside the sdk folder into the
/// patched_sdk folder. For the VM< this includes files under 'runtime/bin/',
/// for flutter, this is includes also the ui library.
_copyExtraLibraries(String sdkOut, Map<String, Map<String, String>> locations) {
if (forDart2js) return;
var base = path.fromUri(Platform.script);
var dartDir = path.dirname(path.dirname(path.absolute(base)));
var builtinLibraryIn = path.join(dartDir, 'runtime', 'bin', 'builtin.dart');
var builtinLibraryOut = path.join(sdkOut, '_builtin', '_builtin.dart');
_writeSync(builtinLibraryOut, readInputFile(builtinLibraryIn));
addLocation(locations, '_builtin', path.join('_builtin', '_builtin.dart'));
if (forFlutter) {
// Flutter repo has this layout:
// engine/src/
// third_party/dart/
// [third_party/]flutter/
var srcDir = path
var flutterDir = new Directory(path.join(srcDir, 'flutter'));
if (!flutterDir.existsSync()) {
// In Fuchsia Flutter is under 'third_party'.
flutterDir = new Directory(path.join(srcDir, 'third_party', 'flutter'));
var uiLibraryInDir = new Directory(path.join(flutterDir.path, 'lib', 'ui'));
for (var file in uiLibraryInDir.listSync()) {
if (!file.path.endsWith('.dart')) continue;
var name = path.basename(file.path);
var uiLibraryOut = path.join(sdkOut, 'ui', name);
_writeSync(uiLibraryOut, readInputFile(file.path));
addLocation(locations, 'ui', path.join('ui', 'ui.dart'));
if (!forFlutterRelease) {
// vmservice should be present unless we build release flavor of Flutter.
// TODO( Consider producing separate Flutter
// vmservice.dill with these vmservice libraries.
for (var file in ['loader.dart', 'server.dart', 'vmservice_io.dart']) {
var libraryIn = path.join(dartDir, 'runtime', 'bin', 'vmservice', file);
var libraryOut = path.join(sdkOut, 'vmservice_io', file);
_writeSync(libraryOut, readInputFile(libraryIn));
addLocation(locations, 'vmservice_sky',
path.join('vmservice_io', 'vmservice_io.dart'));
locations, '_vmservice', path.join('vmservice', 'vmservice.dart'));
path.join(sdkOut, 'diagnostic_server.dart'),
readInputFile(path.join(flutterDir.path, 'shell', 'common',
'diagnostic', 'diagnostic_server.dart')));
addLocation(locations, 'diagnostic_server', 'diagnostic_server.dart');
_applyPatch(SdkLibrary library, String sdkLibIn, String patchIn, String sdkOut,
Map<String, Map<String, String>> locations) {
var libraryOut = path.join(sdkLibIn, library.path);
var libraryIn = libraryOut;
var libraryFile = getInputFile(libraryIn, canBeMissing: true);
if (libraryFile != null) {
addLocation(locations, Uri.parse(library.shortName).path,
path.relative(libraryOut, from: sdkLibIn));
var outPaths = <String>[libraryOut];
var libraryContents = libraryFile.readAsStringSync();
int inputModifyTime = libraryFile.lastModifiedSync().millisecondsSinceEpoch;
var partFiles = <File>[];
for (var part in parseDirectives(libraryContents).directives) {
if (part is PartDirective) {
var partPath = part.uri.stringValue;
outPaths.add(path.join(path.dirname(libraryOut), partPath));
var partFile =
getInputFile(path.join(path.dirname(libraryIn), partPath));
inputModifyTime = math.max(inputModifyTime,
// See if we can find a patch file.
var patchPath;
var patchFile;
if (forVipunen) {
patchPath = path.join(sdkLibIn, '../../vipunen/patches/' + path.basenameWithoutExtension(libraryIn) + '_patch.dart');
patchFile = getInputFile(patchPath, canBeMissing: true);
print('${patchPath} -> ${patchFile}');
if (patchFile == null) {
patchPath = path.join(
patchIn, path.basenameWithoutExtension(libraryIn) + '_patch.dart');
patchFile = getInputFile(patchPath, canBeMissing: true);
if (patchFile != null) {
inputModifyTime = math.max(
inputModifyTime, patchFile.lastModifiedSync().millisecondsSinceEpoch);
// Compute output paths
outPaths = outPaths
.map((p) => path.join(sdkOut, path.relative(p, from: sdkLibIn)))
// Compare output modify time with input modify time.
bool needsUpdate = false;
for (var outPath in outPaths) {
var outFile = new File(outPath);
if (!outFile.existsSync() ||
outFile.lastModifiedSync().millisecondsSinceEpoch < inputModifyTime) {
needsUpdate = true;
if (needsUpdate) {
var contents = <String>[libraryContents];
contents.addAll( => f.readAsStringSync()));
if (patchFile != null) {
var patchContents = patchFile.readAsStringSync();
contents = _patchLibrary(patchFile.path, contents, patchContents);
for (var i = 0; i < outPaths.length; i++) {
_writeSync(outPaths[i], contents[i]);
/// Writes a file, creating the directory if needed.
void _writeSync(String filePath, String contents) {
var outDir = new Directory(path.dirname(filePath));
if (!outDir.existsSync()) outDir.createSync(recursive: true);
new File(filePath).writeAsStringSync(contents);
/// Merges dart:* library code with code from *_patch.dart file.
/// Takes a list of the library's parts contents, with the main library contents
/// first in the list, and the contents of the patch file.
/// The result will have `@patch` implementations merged into the correct place
/// (e.g. the class or top-level function declaration) and all other
/// declarations introduced by the patch will be placed into the main library
/// file.
/// This is purely a syntactic transformation. Unlike dart2js patch files, there
/// is no semantic meaning given to the *_patch files, and they do not magically
/// get their own library scope, etc.
/// Editorializing: the dart2js approach requires a Dart front end such as
/// package:analyzer to semantically model a feature beyond what is specified
/// in the Dart language. Since this feature is only for the convenience of
/// writing the dart:* libraries, and not a tool given to Dart developers, it
/// seems like a non-ideal situation. Instead we keep the preprocessing simple.
List<String> _patchLibrary(
String name, List<String> partsContents, String patchContents) {
var results = <StringEditBuffer>[];
// Parse the patch first. We'll need to extract bits of this as we go through
// the other files.
final patchFinder = new PatchFinder.parseAndVisit(name, patchContents);
// Merge `external` declarations with the corresponding `@patch` code.
for (var partContent in partsContents) {
var partEdits = new StringEditBuffer(partContent);
var partUnit = parseCompilationUnit(partContent);
partUnit.accept(new PatchApplier(partEdits, patchFinder));
if (patchFinder.patches.length != patchFinder.applied.length) {
print('Some elements marked as @patch do not have corresponding elements:');
for (var patched in patchFinder.patches.keys) {
if (!patchFinder.applied.contains(patched)) {
print('*** ${patched}');
throw "Failed to apply all @patch-es";
return new List<String>.from( => e.toString()));
final String injectedCidFields = [
].map((name) => "static final int cid${name} = 0;").join('\n');
/// Merge `@patch` declarations into `external` declarations.
class PatchApplier extends GeneralizingAstVisitor {
final StringEditBuffer edits;
final PatchFinder patch;
bool _isLibrary = true; // until proven otherwise.
PatchApplier(this.edits, this.patch);
visitCompilationUnit(CompilationUnit node) {
if (_isLibrary) _mergeUnpatched(node);
void _merge(AstNode node, int pos) {
var code = patch.contents.substring(node.offset, node.end);
// We inject a number of static fields into dart:internal.ClassID class.
// These fields represent various VM class ids and are only used to
// make core libraries compile. Kernel reader will actually ignore these
// fields and instead inject concrete constants into this class.
if (node is ClassDeclaration && == 'ClassID') {
code = code.replaceFirst(new RegExp(r'}$'), injectedCidFields + '}');
edits.insert(pos, '\n' + code);
/// Merges directives and declarations that are not `@patch` into the library.
void _mergeUnpatched(CompilationUnit unit) {
// Merge imports from the patch
// TODO(jmesserly): remove duplicate imports
// To patch a library, we must have a library directive
var libDir = unit.directives.first as LibraryDirective;
int importPos = unit.directives
.lastWhere((d) => d is ImportDirective, orElse: () => libDir)
for (var d in patch.unit.directives.where((d) => d is ImportDirective)) {
_merge(d, importPos);
int partPos = unit.directives.last.end;
for (var d in patch.unit.directives.where((d) => d is PartDirective)) {
_merge(d, partPos);
// Merge declarations from the patch
int declPos = edits.original.length;
for (var d in patch.mergeDeclarations) {
_merge(d, declPos);
visitPartOfDirective(PartOfDirective node) {
_isLibrary = false;
visitFunctionDeclaration(FunctionDeclaration node) {
/// Merge patches and extensions into the class
visitClassDeclaration(ClassDeclaration node) {
final qname = _qualifiedName(node);
if (patch.erase.contains(qname)) {
print('${node.leftBracket.end} ${node.rightBracket.offset}');
edits.replace(node.leftBracket.end, node.rightBracket.offset, '');
final extendsPatch = patch.extendsPatches[qname];
if (extendsPatch != null) {
edits.replace(node.extendsClause.offset, node.extendsClause.end, 'extends ${extendsPatch}');
var mergeMembers = patch.mergeMembers[_qualifiedName(node)];
if (mergeMembers == null) return;
// Merge members from the patch
var pos = node.members.last.end;
for (var member in mergeMembers) {
var code = patch.contents.substring(member.offset, member.end);
edits.insert(pos, '\n\n ' + code);
void _maybePatch(AstNode node) {
if (node is FieldDeclaration) return;
var externalKeyword = (node as dynamic).externalKeyword;
var name = _qualifiedName(node);
var patchNode = patch.patches[name];
if (patchNode == null) {
if (externalKeyword != null && _shouldHaveImplementation(name)) {
print('warning: patch not found for $name: $node');
exitCode = 1;
Annotation patchMeta = patchNode.metadata.lastWhere(_isPatchAnnotation);
int start =;
var code = patch.contents.substring(start, patchNode.end);
// For some node like static fields, the node's offset doesn't include
// the external keyword. Also starting from the keyword lets us preserve
// documentation comments.
edits.replace(externalKeyword?.offset ?? node.offset, node.end, code);
/// Whether a member should have an implementation after patching the SDK.
/// True for most members except for the *.fromEnvironment constructors under
/// the dart2js target.
bool _shouldHaveImplementation(String qualifiedName) {
if (!forDart2js) return true;
// Note: dart2js implements int.fromEnvironment, bool.fromEnvironment
// and String.fromEnvironment directly and expects the SDK code to
// have an external declaration.
var isFromEnvironment = const [
return !isFromEnvironment;
class PatchFinder extends GeneralizingAstVisitor {
final String contents;
final CompilationUnit unit;
final Map patches = <String, Declaration>{};
final Map mergeMembers = <String, List<ClassMember>>{};
final List mergeDeclarations = <CompilationUnitMember>[];
final Set<String> applied = new Set<String>();
final Set<String> erase = new Set<String>();
final Map<String, String> extendsPatches = <String, String>{};
PatchFinder.parseAndVisit(String name, String contents)
: contents = contents,
unit = parseCompilationUnit(contents, name: name) {
visitCompilationUnitMember(CompilationUnitMember node) {
visitClassDeclaration(ClassDeclaration node) {
if (_isPatch(node)) {
if (_hasAnnotation(node, 'erase')) {
if (_hasAnnotation(node, 'patchExtends')) {
extendsPatches[_qualifiedName(node)] = node.extendsClause != null ? : 'Object';
var members = <ClassMember>[];
for (var member in node.members) {
if (_isPatch(member)) {
patches[_qualifiedName(member)] = member;
} else {
if (members.isNotEmpty) {
mergeMembers[_qualifiedName(node)] = members;
} else {
visitFunctionDeclaration(FunctionDeclaration node) {
if (_isPatch(node)) {
patches[_qualifiedName(node)] = node;
} else {
visitFunctionBody(node) {} // skip method bodies
String _qualifiedName(Declaration node) {
var parent = node.parent;
var className = '';
if (parent is ClassDeclaration) {
className = + '.';
var name = (node as dynamic).name;
name = (name != null ? : '');
var accessor = '';
if (node is MethodDeclaration) {
if (node.isGetter)
accessor = 'get:';
else if (node.isSetter) accessor = 'set:';
if (name == '-' && node.isOperator && node.parameters.parameters.length == 0) {
name = 'unary-';
return className + accessor + name;
bool _isPatch(AnnotatedNode node) => node.metadata.any(_isPatchAnnotation);
bool _hasAnnotation(AnnotatedNode node, String name) => node.metadata.any((ann) => _isAnnotation(ann, name));
bool _isAnnotation(Annotation m, String name) => == name && m.constructorName == null && m.arguments == null;
bool _isPatchAnnotation(Annotation m) => _isAnnotation(m, 'patch');
/// Editable string buffer.
/// Applies a series of edits (insertions, removals, replacements) using
/// original location information, and composes them into the edited string.
/// For example, starting with a parsed AST with original source locations,
/// this type allows edits to be made without regards to other edits.
class StringEditBuffer {
final String original;
final _edits = <_StringEdit>[];
/// Creates a new transaction.
bool get hasEdits => _edits.length > 0;
/// Edit the original text, replacing text on the range [begin] and
/// exclusive [end] with the [replacement] string.
void replace(int begin, int end, String replacement) {
_edits.add(new _StringEdit(begin, end, replacement));
/// Insert [string] at [offset].
/// Equivalent to `replace(offset, offset, string)`.
void insert(int offset, String string) => replace(offset, offset, string);
/// Remove text from the range [begin] to exclusive [end].
/// Equivalent to `replace(begin, end, '')`.
void remove(int begin, int end) => replace(begin, end, '');
/// Applies all pending [edit]s and returns a new string.
/// This method is non-destructive: it does not discard existing edits or
/// change the [original] string. Further edits can be added and this method
/// can be called again.
/// Throws [UnsupportedError] if the edits were overlapping. If no edits were
/// made, the original string will be returned.
String toString() {
var sb = new StringBuffer();
if (_edits.length == 0) return original;
// Sort edits by start location.
int consumed = 0;
for (var edit in _edits) {
if (consumed > edit.begin) {
sb = new StringBuffer();
sb.write('overlapping edits. Insert at offset ');
sb.write(' but have consumed ');
sb.write(' input characters. List of edits:');
for (var e in _edits) {
sb.write('\n ');
throw new UnsupportedError(sb.toString());
// Add characters from the original string between this edit and the last
// one, if any.
var betweenEdits = original.substring(consumed, edit.begin);
consumed = edit.end;
// Add any text from the end of the original string that was not replaced.
return sb.toString();
class _StringEdit implements Comparable<_StringEdit> {
final int begin;
final int end;
final String replace;
_StringEdit(this.begin, this.end, this.replace);
int get length => end - begin;
String toString() => '(Edit @ $begin,$end: "$replace")';
int compareTo(_StringEdit other) {
int diff = begin - other.begin;
if (diff != 0) return diff;
return end - other.end;
List<SdkLibrary> _getSdkLibraries(String contents) {
var libraryBuilder = new SdkLibrariesReader_LibraryBuilder(forDart2js);
return libraryBuilder.librariesMap.sdkLibraries;
void addLocation(Map<String, Map<String, String>> locations, String libraryName,
String libraryPath) {
assert(locations[libraryName] == null);
locations[libraryName] = {'uri': '${path.toUri(libraryPath)}'};