Make Sky example game run offline

sky/sdk/lib/mojo/asset_bundle.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:async';
 import 'dart:sky' as sky;
-import "dart:sky.internals" as internals;
+import 'dart:sky.internals' as internals;
+import 'dart:typed_data';
 
 import 'package:mojo/core.dart' as core;
 import 'package:mojom/mojo/asset_bundle/asset_bundle.mojom.dart';
 
 import 'net/fetch.dart';
 import 'net/image_cache.dart' as image_cache;
 import 'shell.dart' as shell;
 
 abstract class AssetBundle {
   void close();
   Future<sky.Image> loadImage(String key);
+  Future<String> loadString(String key);
 }
 
 class NetworkAssetBundle extends AssetBundle {
   NetworkAssetBundle(Uri baseUrl) : _baseUrl = baseUrl;
 
   final Uri _baseUrl;
 
   void close() { }
 
-  Future<sky.Image> loadImage(String name) {
-    Uri url = _baseUrl.resolve(name);
-    return image_cache.load(url.toString());
+  Future<sky.Image> loadImage(String key) {
+    return image_cache.load(_baseUrl.resolve(key).toString());
+  }
+
+  Future<String> loadString(String key) {

[viktorl, 2015/07/10 16:39:37]

It may be worth thinking of calling this loadText or loadTextFile and also have
the option of passing the text encoding.

[abarth-chromium, 2015/07/10 16:42:28]

Yeah, that might be worthwhile.  I was hoping to strongly encourage UTF-8, but
maybe that's not realistic.

+    return fetchString(_baseUrl.resolve(key).toString());
   }
 }
 
 Future _fetchAndUnpackBundle(String relativeUrl, AssetBundleProxy bundle) async {
   core.MojoDataPipeConsumer bundleData = (await fetchUrl(relativeUrl)).body;
   AssetUnpackerProxy unpacker = new AssetUnpackerProxy.unbound();
   shell.requestService("mojo:asset_bundle", unpacker);
   unpacker.ptr.unpackZipStream(bundleData, bundle);
   unpacker.close();
 }
 
 class MojoAssetBundle extends AssetBundle {
   MojoAssetBundle(AssetBundleProxy this._bundle);
 
   factory MojoAssetBundle.fromNetwork(String relativeUrl) {
     AssetBundleProxy bundle = new AssetBundleProxy.unbound();
     _fetchAndUnpackBundle(relativeUrl, bundle);
     return new MojoAssetBundle(bundle);
   }
 
-  AssetBundleProxy _bundle;
+  final AssetBundleProxy _bundle;
   Map<String, Future<sky.Image>> _imageCache = new Map<String, Future<sky.Image>>();
+  Map<String, Future<String>> _stringCache = new Map<String, Future<String>>();
 
   void close() {
     _bundle.close();
     _bundle = null;
     _imageCache = null;
   }
 
-  Future<sky.Image> loadImage(String name) {
-    return _imageCache.putIfAbsent(name, () {
+  Future<sky.Image> loadImage(String key) {
+    return _imageCache.putIfAbsent(key, () {
       Completer<sky.Image> completer = new Completer<sky.Image>();
-      _bundle.ptr.getAsStream(name).then((response) {
+      _bundle.ptr.getAsStream(key).then((response) {
         new sky.ImageDecoder(response.assetData.handle.h, completer.complete);
       });
       return completer.future;
     });
   }
+
+  Future<String> _fetchString(String key) async {
+    core.MojoDataPipeConsumer pipe = (await _bundle.ptr.getAsStream(key)).assetData;
+    ByteData data = await core.DataPipeDrainer.drainHandle(pipe);
+    return new String.fromCharCodes(new Uint8List.view(data.buffer));
+  }
+
+  Future<String> loadString(String key) {
+    return _stringCache.putIfAbsent(key, () => _fetchString(key));
+  }
 }
 
 AssetBundle _initRootBundle() {
   try {
     AssetBundleProxy bundle = new AssetBundleProxy.fromHandle(
         new core.MojoHandle(internals.takeRootBundleHandle()));
     return new MojoAssetBundle(bundle);
   } catch (e) {
     return null;
   }
 }
 
 final AssetBundle rootBundle = _initRootBundle();