Support specifying a fixed list of assets on the command line (#6857)

packages/flutter_tools/lib/src/asset.dart

@@ -52,9 +52,33 @@ class AssetBundle {
   static const String _kFontSetMaterial = 'material';
   static const String _kFontSetRoboto = 'roboto';
 
+  bool _fixed = false;
   DateTime _lastBuildTimestamp;
 
+  /// Constructs an [AssetBundle] that gathers the set of assets from the
+  /// flutter.yaml manifest.
+  AssetBundle();
+
+  /// Constructs an [AssetBundle] with a fixed set of assets.
+  /// [projectRoot] The absolute path to the project root.
+  /// [projectAssets] comma separated list of assets.
+  AssetBundle.fixed(String projectRoot, String projectAssets) {
+    _fixed = true;
+    if ((projectRoot == null) || (projectAssets == null))
+      return;
+
+    List<String> assets = projectAssets.split(',');
+    for (String asset in assets) {
+      final String assetPath = path.join(projectRoot, asset);
+      final String archivePath = asset;
+      entries.add(
+          new AssetBundleEntry.fromFile(archivePath, new File(assetPath)));
+    }
+  }
+
   bool needsBuild({String manifestPath: defaultManifestPath}) {
+    if (_fixed)
+      return false;
     if (_lastBuildTimestamp == null)
       return true;
 

packages/flutter_tools/lib/src/commands/run.dart

@@ -63,9 +63,12 @@ class RunCommand extends RunCommandBase {
     argParser.addOption('packages',
         hide: !verboseHelp,
         help: 'Specify the path to the .packages file.');
-    argParser.addOption('project_root',
+    argParser.addOption('project-root',
         hide: !verboseHelp,
         help: 'Specify the project root directory.');
+    argParser.addOption('project-assets',
+        hide: !verboseHelp,
+        help: 'Specify the project assets relative to the root directory.');
     argParser.addFlag('machine',
         hide: !verboseHelp,
         help: 'Handle machine structured JSON command input\n'
@@ -219,8 +222,9 @@ class RunCommand extends RunCommandBase {
         debuggingOptions: options,
         benchmarkMode: argResults['benchmark'],
         applicationBinary: argResults['use-application-binary'],
-        projectRootPath: argResults['project_root'],
+        projectRootPath: argResults['project-root'],
         packagesFilePath: argResults['packages'],
+        projectAssets: argResults['project-assets']
       );
     } else {
       runner = new RunAndStayResident(

packages/flutter_tools/lib/src/hot.dart

@@ -99,6 +99,7 @@ class HotRunner extends ResidentRunner {
     this.applicationBinary,
     String projectRootPath,
     String packagesFilePath,
+    String projectAssets,
   }) : super(device,
              target: target,
              debuggingOptions: debuggingOptions,
@@ -106,6 +107,10 @@ class HotRunner extends ResidentRunner {
     _projectRootPath = projectRootPath ?? Directory.current.path;
     _packagesFilePath =
             packagesFilePath ?? path.absolute(PackageMap.globalPackagesPath);
+    if (projectAssets != null)
+      _bundle = new AssetBundle.fixed(_projectRootPath, projectAssets);
+    else
+      _bundle = new AssetBundle();
   }
 
   ApplicationPackage _package;
@@ -116,7 +121,8 @@ class HotRunner extends ResidentRunner {
   bool get prebuiltMode => applicationBinary != null;
   Set<String> _dartDependencies;
   int _observatoryPort;
-  final AssetBundle bundle = new AssetBundle();
+  AssetBundle _bundle;
+  AssetBundle get bundle => _bundle;
   final bool benchmarkMode;
   final Map<String, int> benchmarkData = new Map<String, int>();
 

packages/flutter_tools/test/all.dart

@@ -15,6 +15,7 @@ import 'analyze_duplicate_names_test.dart' as analyze_duplicate_names_test;
 import 'analyze_test.dart' as analyze_test;
 import 'android_device_test.dart' as android_device_test;
 import 'android_sdk_test.dart' as android_sdk_test;
+import 'asset_bundle_test.dart' as asset_bundle_test;
 import 'application_package_test.dart' as application_package_test;
 import 'base_utils_test.dart' as base_utils_test;
 import 'channel_test.dart' as channel_test;
@@ -49,6 +50,7 @@ void main() {
   android_device_test.main();
   android_sdk_test.main();
   application_package_test.main();
+  asset_bundle_test.main();
   base_utils_test.main();
   channel_test.main();
   config_test.main();

packages/flutter_tools/test/asset_bundle_test.dart

@@ -0,0 +1,60 @@
+// Copyright 2016 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:io';
+import 'dart:convert';
+import 'package:flutter_tools/src/asset.dart';
+import 'package:path/path.dart' as path;
+import 'package:test/test.dart';
+
+void main()  {
+  // Create a temporary directory and write a single file into it.
+  Directory tempDir = Directory.systemTemp.createTempSync();
+  String projectRoot = tempDir.path;
+  String assetPath = 'banana.txt';
+  String assetContents = 'banana';
+  File tempFile = new File(path.join(projectRoot, assetPath));
+  tempFile.parent.createSync(recursive: true);
+  tempFile.writeAsBytesSync(UTF8.encode(assetContents));
+
+  // Fixed asset bundle tests.
+  group('AssetBundle.fixed', () {
+    test('empty strings', () async {
+      expect(new AssetBundle.fixed(null, null), isNotNull);
+      expect(new AssetBundle.fixed('', ''), isNotNull);
+      expect(new AssetBundle.fixed(null, null).entries, isEmpty);
+    });
+    test('does not need a rebuild', () async {
+      expect(new AssetBundle.fixed(null, null).needsBuild(), isFalse);
+    });
+    test('single entry', () async {
+      AssetBundle ab = new AssetBundle.fixed('', 'apple.txt');
+      expect(ab.entries, isNotEmpty);
+      expect(ab.entries.length, 1);
+      AssetBundleEntry entry = ab.entries.first;
+      expect(entry, isNotNull);
+      expect(entry.archivePath, 'apple.txt');
+    });
+    test('two entries', () async {
+      AssetBundle ab = new AssetBundle.fixed('', 'apple.txt,packages/flutter_gallery_assets/shrine/products/heels.png');
+      expect(ab.entries, isNotEmpty);
+      expect(ab.entries.length, 2);
+      AssetBundleEntry firstEntry = ab.entries.first;
+      expect(firstEntry, isNotNull);
+      expect(firstEntry.archivePath, 'apple.txt');
+      AssetBundleEntry lastEntry = ab.entries.last;
+      expect(lastEntry, isNotNull);
+      expect(lastEntry.archivePath, 'packages/flutter_gallery_assets/shrine/products/heels.png');
+    });
+    test('file contents', () async {
+      AssetBundle ab = new AssetBundle.fixed(projectRoot, assetPath);
+      expect(ab.entries, isNotEmpty);
+      expect(ab.entries.length, 1);
+      AssetBundleEntry entry = ab.entries.first;
+      expect(entry, isNotNull);
+      expect(entry.archivePath, assetPath);
+      expect(assetContents, UTF8.decode(entry.contentsAsBytes()));
+    });
+  });
+}