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// Copyright (c) 2016, 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.
library dev_compiler.web.web_command;
import 'dart:async';
import 'dart:convert';
import 'dart:math' as math;
import 'dart:html' show HttpRequest;
import 'dart:typed_data';
import 'package:analyzer/file_system/file_system.dart' show ResourceUriResolver;
import 'package:analyzer/file_system/memory_file_system.dart'
show MemoryResourceProvider;
import 'package:analyzer/src/summary/idl.dart' show PackageBundle;
import 'package:analyzer/src/summary/package_bundle_reader.dart'
show SummaryDataStore;
import 'package:analyzer/src/dart/resolver/scope.dart' show Scope;
import 'package:args/command_runner.dart';
import 'package:dev_compiler/src/analyzer/context.dart' show AnalyzerOptions;
import 'package:dev_compiler/src/analyzer/command.dart';
import 'package:dev_compiler/src/analyzer/driver.dart';
import 'package:dev_compiler/src/analyzer/module_compiler.dart';
import 'package:dev_compiler/src/compiler/module_builder.dart';
import 'package:js/js.dart';
import 'package:path/path.dart' as p;
typedef void MessageHandler(Object message);
class JSIterator<V> {}
class JSMap<K, V> {
external V get(K v);
external set(K k, V v);
external JSIterator<K> keys();
external JSIterator<V> values();
external int get size;
external List<V> iteratorToList<V>(JSIterator<V> iterator);
class CompileResult {
external factory CompileResult(
{String code, List<String> errors, bool isValid});
typedef CompileModule(String imports, String body, String libraryName,
String existingLibrary, String fileName);
/// The command for invoking the modular compiler.
class WebCompileCommand extends Command {
get name => 'compile';
get description => 'Compile a set of Dart files into a JavaScript module.';
final MessageHandler messageHandler;
WebCompileCommand({MessageHandler messageHandler})
: this.messageHandler = messageHandler ?? print {
ddcArgParser(argParser: argParser, help: false);
Function run() {
return requestSummaries;
Future<Null> requestSummaries(String sdkUrl, JSMap<String, String> summaryMap,
Function onCompileReady, Function onError, Function onProgress) async {
var sdkRequest;
var progress = 0;
// Add 1 to the count for the SDK summary.
var total = summaryMap.size + 1;
// No need to report after every summary is loaded. Posting about 100
// progress updates should be more than sufficient for users to understand
// how long loading will take.
num progressDelta = math.max(total / 100, 1);
num nextProgressToReport = 0;
maybeReportProgress() {
if (nextProgressToReport > progress && progress != total) return;
nextProgressToReport += progressDelta;
if (onProgress != null) onProgress(progress, total);
try {
sdkRequest = await HttpRequest.request(sdkUrl,
responseType: "arraybuffer",
mimeType: "application/octet-stream",
withCredentials: true);
} catch (error) {
onError('Dart sdk summaries failed to load: $error. url: $sdkUrl');
return null;
var sdkBytes = (sdkRequest.response as ByteBuffer).asUint8List();
// Map summary URLs to HttpRequests.
var summaryRequests =
iteratorToList(summaryMap.values()).map((String summaryUrl) async {
var request = await HttpRequest.request(summaryUrl,
responseType: "arraybuffer", mimeType: "application/octet-stream");
return request;
try {
var summaryResponses = await Future.wait(summaryRequests);
// Map summary responses to summary bytes.
List<List<int>> summaryBytes = summaryResponses
.map((response) => (response.response as ByteBuffer).asUint8List())
sdkBytes, summaryBytes, iteratorToList(summaryMap.keys())));
} catch (error) {
onError('Summaries failed to load: $error');
List<Function> setUpCompile(List<int> sdkBytes, List<List<int>> summaryBytes,
List<String> moduleIds) {
var dartSdkSummaryPath = '/dart-sdk/lib/_internal/web_sdk.sum';
var resources = MemoryResourceProvider()
..newFileWithBytes(dartSdkSummaryPath, sdkBytes);
var options = AnalyzerOptions.basic(
dartSdkPath: '/dart-sdk', dartSdkSummaryPath: dartSdkSummaryPath);
var summaryData = SummaryDataStore([], resourceProvider: resources);
var compilerOptions = CompilerOptions.fromArguments(argResults);
compilerOptions.replCompile = true;
compilerOptions.libraryRoot = '/';
for (var i = 0; i < summaryBytes.length; i++) {
var bytes = summaryBytes[i];
// Packages with no dart source files will have empty invalid summaries.
if (bytes.isEmpty) continue;
var moduleId = moduleIds[i];
var url = '/$moduleId.api.ds';
summaryData.addBundle(url, PackageBundle.fromBuffer(bytes));
compilerOptions.summaryModules[url] = moduleId;
options.analysisRoot = '/web-compile-root';
options.fileResolvers = [ResourceUriResolver(resources)];
options.resourceProvider = resources;
var driver = CompilerAnalysisDriver(options, summaryData: summaryData);
var resolveFn = (String url) {
var packagePrefix = 'package:';
var uri = Uri.parse(url);
var base = p.basename(url);
var parts = uri.pathSegments;
var match;
int bestScore = 0;
for (var candidate in summaryData.uriToSummaryPath.keys) {
if (p.basename(candidate) != base) continue;
List<String> candidateParts = p.dirname(candidate).split('/');
var first = candidateParts.first;
// Process and strip "package:" prefix.
if (first.startsWith(packagePrefix)) {
first = first.substring(packagePrefix.length);
candidateParts[0] = first;
// Handle convention that directory foo/bar/baz is given package name
if (first.contains('.')) {
candidateParts = (first.split('.'))..addAll(candidateParts.skip(1));
// If file name and extension don't match... give up.
int i = parts.length - 1;
int j = candidateParts.length - 1;
int score = 1;
// Greedy algorithm finding matching path segments from right to left
// skipping segments on the candidate path unless the target path
// segment is named lib.
while (i >= 0 && j >= 0) {
if (parts[i] == candidateParts[j]) {
if (j == 0 && i == 0) {
// Arbitrary bonus if we matched all parts of the input
// and used up all parts of the output.
score += 10;
} else {
// skip unmatched lib directories from the input
// otherwise skip unmatched parts of the candidate.
if (parts[i] == 'lib') {
} else {
if (score > bestScore) {
match = candidate;
return match;
CompileModule compileFn = (String imports, String body, String libraryName,
String existingLibrary, String fileName) {
// Instead of returning a single function, return a pair of functions.
// Create a new virtual File that contains the given Dart source.
String sourceCode;
if (existingLibrary == null) {
sourceCode = imports + body;
} else {
var dir = p.dirname(existingLibrary);
// Need to pull in all the imports from the existing library and
// re-export all privates as privates in this library.
// Assumption: summaries are available for all libraries, including any
// source files that were compiled; we do not need to reconstruct any
// summary data here.
var unlinked = driver.summaryData.unlinkedMap[existingLibrary];
if (unlinked == null) {
throw "Unable to get library element for `$existingLibrary`.";
var sb = StringBuffer(imports);
// TODO(jacobr): we need to add a proper Analyzer flag specifing that
// cross-library privates should be in scope instead of this hack.
// We set the private name prefix for scope resolution to an invalid
// character code so that the analyzer ignores normal Dart private
// scoping rules for top level names allowing REPL users to access
// privates in arbitrary libraries. The downside of this scheme is it is
// possible to get errors if privates in the current library and
// imported libraries happen to have exactly the same name.
// We emulate running code in the context of an existing library by
// importing that library and all libraries it imports.
sb.write('import ${json.encode(existingLibrary)};\n');
for (var import in unlinked.imports) {
if (import.uri == null || import.isImplicit) continue;
var uri = import.uri;
// dart: and package: uris are not relative but the path package
// thinks they are. We have to provide absolute uris as our library
// has a different directory than the library we are pretending to be.
if (p.isRelative(uri) &&
!uri.startsWith('package:') &&
!uri.startsWith('dart:')) {
uri = p.normalize(p.join(dir, uri));
sb.write('import ${json.encode(uri)}');
if (import.prefixReference != 0) {
var prefix = unlinked.references[import.prefixReference].name;
sb.write(' as $prefix');
for (var combinator in import.combinators) {
if (combinator.shows.isNotEmpty) {
sb.write(' show ${combinator.shows.join(', ')}');
} else if (combinator.hides.isNotEmpty) {
sb.write(' hide ${combinator.hides.join(', ')}');
} else {
throw 'Unexpected element combinator';
sourceCode = sb.toString();
resources.newFile(fileName, sourceCode);
var name = p.toUri(libraryName).toString();
compilerOptions.moduleName = name;
JSModuleFile module =
compileWithAnalyzer(driver, [fileName], options, compilerOptions);
var moduleCode = '';
if (module.isValid) {
moduleCode =
module.getCode(ModuleFormat.legacyConcat, name, name + '.map').code;
return CompileResult(
code: moduleCode, isValid: module.isValid, errors: module.errors);
return [allowInterop(compileFn), allowInterop(resolveFn)];
/// Thrown when the input source code has errors.
class CompileErrorException implements Exception {
toString() => '\nPlease fix all errors before compiling (warnings are okay).';