'flutter start' calls 'flutter apk' if necessary.

flutter start no longer depends on a pre-built SkyShell.apk. It builds a
new one, as long as an AndroidManifest.xml exists.

We rebuild the .apk every time either AndroidManifest.xml or
flutter.yaml changes.

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

@@ -8,15 +8,19 @@ import 'dart:io';
 
 import 'package:path/path.dart' as path;
 import 'package:yaml/yaml.dart';
+import 'package:xml/xml.dart' as xml;
 
 import '../android/device_android.dart';
+import '../application_package.dart';
 import '../artifacts.dart';
 import '../base/context.dart';
 import '../base/file_system.dart';
 import '../base/process.dart';
 import '../build_configuration.dart';
+import '../device.dart';
 import '../flx.dart' as flx;
 import '../runner/flutter_command.dart';
+import '../toolchain.dart';
 import 'start.dart';
 
 const String _kDefaultAndroidManifestPath = 'apk/AndroidManifest.xml';
@@ -25,6 +29,7 @@ const String _kDefaultResourcesPath = 'apk/res';
 
 const String _kFlutterManifestPath = 'flutter.yaml';
 const String _kPubspecYamlPath = 'pubspec.yaml';
+const String _kPackagesStatusPath = '.packages';
 
 // Alias of the key provided in the Chromium debug keystore
 const String _kDebugKeystoreKeyAlias = "chromiumdebugkey";
@@ -132,6 +137,14 @@ class _ApkComponents {
   Directory resources;
 }
 
+class ApkKeystoreInfo {
+  String keystore;
+  String password;
+  String keyAlias;
+  String keyPassword;
+  ApkKeystoreInfo({ this.keystore, this.password, this.keyAlias, this.keyPassword });
+}
+
 // TODO(mpcomplete): find a better home for this.
 dynamic _loadYamlFile(String path) {
   if (!FileSystemEntity.isFileSync(path))
@@ -179,7 +192,30 @@ class ApkCommand extends FlutterCommand {
         help: 'Password for the entry within the keystore.');
   }
 
-  Future _findServices(_ApkComponents components) async {
+  @override
+  Future<int> runInProject() async {
+    await downloadToolchain();
+    return await buildAndroid(
+      toolchain: toolchain,
+      configs: buildConfigurations,
+      enginePath: runner.enginePath,
+      force: true,
+      manifest: argResults['manifest'],
+      resources: argResults['resources'],
+      outputFile: argResults['output-file'],
+      target: argResults['target'],
+      flxPath: argResults['flx'],
+      keystore: argResults['keystore'].isEmpty ? null : new ApkKeystoreInfo(
+        keystore: argResults['keystore'],
+        password: argResults['keystore-password'],
+        keyAlias: argResults['keystore-key-alias'],
+        keyPassword: argResults['keystore-key-password']
+      )
+    );
+  }
+}
+
+Future _findServices(_ApkComponents components) async {
   if (!ArtifactStore.isPackageRootValid)
     return;
 
@@ -208,24 +244,25 @@ class ApkCommand extends FlutterCommand {
       }
     }
   }
-  }
+}
 
-  Future<_ApkComponents> _findApkComponents(BuildConfiguration config) async {
+Future<_ApkComponents> _findApkComponents(
+  BuildConfiguration config, String enginePath, String manifest, String resources
+) async {
   String androidSdkPath;
   List<String> artifactPaths;
-    if (runner.enginePath != null) {
-      androidSdkPath = '${runner.enginePath}/third_party/android_tools/sdk';
+  if (enginePath != null) {
+    androidSdkPath = '$enginePath/third_party/android_tools/sdk';
     artifactPaths = [
-        '${runner.enginePath}/third_party/icu/android/icudtl.dat',
+      '$enginePath/third_party/icu/android/icudtl.dat',
       '${config.buildDir}/gen/sky/shell/shell/classes.dex.jar',
       '${config.buildDir}/gen/sky/shell/shell/shell/libs/armeabi-v7a/libsky_shell.so',
-        '${runner.enginePath}/build/android/ant/chromium-debug.keystore',
+      '$enginePath/build/android/ant/chromium-debug.keystore',
     ];
   } else {
     androidSdkPath = AndroidDevice.getAndroidSdkPath();
-      if (androidSdkPath == null) {
+    if (androidSdkPath == null)
       return null;
-      }
     List<ArtifactType> artifactTypes = <ArtifactType>[
       ArtifactType.androidIcuData,
       ArtifactType.androidClassesJar,
@@ -240,12 +277,12 @@ class ApkCommand extends FlutterCommand {
 
   _ApkComponents components = new _ApkComponents();
   components.androidSdk = new Directory(androidSdkPath);
-    components.manifest = new File(argResults['manifest']);
+  components.manifest = new File(manifest);
   components.icuData = new File(artifactPaths[0]);
   components.jars = [new File(artifactPaths[1])];
   components.libSkyShell = new File(artifactPaths[2]);
   components.debugKeystore = new File(artifactPaths[3]);
-    components.resources = new Directory(argResults['resources']);
+  components.resources = new Directory(resources);
 
   await _findServices(components);
 
@@ -275,16 +312,16 @@ class ApkCommand extends FlutterCommand {
   }
 
   return components;
-  }
+}
 
-  // Outputs a services.json file for the flutter engine to read. Format:
-  // {
-  //   services: [
-  //     { name: string, class: string },
-  //     ...
-  //   ]
-  // }
-  void _generateServicesConfig(File servicesConfig, List<Map<String, String>> servicesIn) {
+// Outputs a services.json file for the flutter engine to read. Format:
+// {
+//   services: [
+//     { name: string, class: string },
+//     ...
+//   ]
+// }
+void _generateServicesConfig(File servicesConfig, List<Map<String, String>> servicesIn) {
   List<Map<String, String>> services =
       servicesIn.map((Map<String, String> service) => {
         'name': service['name'],
@@ -293,9 +330,11 @@ class ApkCommand extends FlutterCommand {
 
   Map<String, dynamic> json = { 'services': services };
   servicesConfig.writeAsStringSync(JSON.encode(json), mode: FileMode.WRITE, flush: true);
-  }
+}
 
-  int _buildApk(_ApkComponents components, String flxPath) {
+int _buildApk(
+  _ApkComponents components, String flxPath, ApkKeystoreInfo keystore, String outputFile
+) {
   Directory tempDir = Directory.systemTemp.createTempSync('flutter_tools');
   try {
     _ApkBuilder builder = new _ApkBuilder(components.androidSdk.path);
@@ -319,11 +358,11 @@ class ApkCommand extends FlutterCommand {
     builder.package(unalignedApk, components.manifest, assetBuilder.directory,
                     artifactBuilder.directory, components.resources);
 
-      int signResult = _signApk(builder, components, unalignedApk);
+    int signResult = _signApk(builder, components, unalignedApk, keystore);
     if (signResult != 0)
       return signResult;
 
-      File finalApk = new File(argResults['output-file']);
+    File finalApk = new File(outputFile);
     ensureDirectoryExists(finalApk.path);
     builder.align(unalignedApk, finalApk);
 
@@ -333,51 +372,115 @@ class ApkCommand extends FlutterCommand {
   } finally {
     tempDir.deleteSync(recursive: true);
   }
-  }
+}
 
-  int _signApk(_ApkBuilder builder, _ApkComponents components, File apk) {
+int _signApk(
+  _ApkBuilder builder, _ApkComponents components, File apk, ApkKeystoreInfo keystoreInfo
+) {
   File keystore;
   String keystorePassword;
   String keyAlias;
   String keyPassword;
 
-    if (argResults['keystore'].isEmpty) {
-      printError('Signing the APK using the debug keystore');
+  if (keystoreInfo == null) {
+    printError('Signing the APK using the debug keystore.');
     keystore = components.debugKeystore;
     keystorePassword = _kDebugKeystorePassword;
     keyAlias = _kDebugKeystoreKeyAlias;
     keyPassword = _kDebugKeystorePassword;
   } else {
-      keystore = new File(argResults['keystore']);
-      keystorePassword = argResults['keystore-password'];
-      keyAlias = argResults['keystore-key-alias'];
+    keystore = new File(keystoreInfo.keystore);
+    keystorePassword = keystoreInfo.password;
+    keyAlias = keystoreInfo.keyAlias;
     if (keystorePassword.isEmpty || keyAlias.isEmpty) {
-        printError('Must provide a keystore password and a key alias');
+      printError('Must provide a keystore password and a key alias.');
       return 1;
     }
-      keyPassword = argResults['keystore-key-password'];
+    keyPassword = keystoreInfo.keyPassword;
     if (keyPassword.isEmpty)
       keyPassword = keystorePassword;
   }
 
   builder.sign(keystore, keystorePassword, keyAlias, keyPassword, apk);
 
+  return 0;
+}
+
+// Creates a new ApplicationPackage from the Android manifest.
+AndroidApk _getApplicationPackage(String apkPath, String manifest) {
+  if (!FileSystemEntity.isFileSync(manifest))
+    return null;
+  String manifestString = new File(manifest).readAsStringSync();
+  xml.XmlDocument document = xml.parse(manifestString);
+
+  Iterable<xml.XmlElement> manifests = document.findElements('manifest');
+  if (manifests.isEmpty)
+    return null;
+  String id = manifests.toList()[0].getAttribute('package');
+
+  String launchActivity;
+  for (xml.XmlElement category in document.findAllElements('category')) {
+    if (category.getAttribute('android:name') == 'android.intent.category.LAUNCHER') {
+      xml.XmlElement activity = category.parent.parent as xml.XmlElement;
+      String activityName = activity.getAttribute('android:name');
+      launchActivity = "$id/$activityName";
+      break;
+    }
+  }
+  if (id == null || launchActivity == null)
+    return null;
+
+  return new AndroidApk(localPath: apkPath, id: id, launchActivity: launchActivity);
+}
+
+// Returns true if the apk is out of date and needs to be rebuilt.
+bool _needsRebuild(String apkPath, String manifest) {
+  FileStat apkStat = FileStat.statSync(apkPath);
+  // Note: This list of dependencies is imperfect, but will do for now. We
+  // purposely don't include the .dart files, because we can load those
+  // over the network without needing to rebuild (at least on Android).
+  List<FileStat> dependenciesStat = [
+    manifest,
+    _kFlutterManifestPath,
+    _kPackagesStatusPath
+  ].map((String path) => FileStat.statSync(path));
+
+  if (apkStat.type == FileSystemEntityType.NOT_FOUND)
+    return true;
+  for (FileStat dep in dependenciesStat) {
+    if (dep.modified.isAfter(apkStat.modified))
+      return true;
+  }
+  return false;
+}
+
+Future<int> buildAndroid({
+  Toolchain toolchain,
+  List<BuildConfiguration> configs,
+  String enginePath,
+  bool force: false,
+  String manifest: _kDefaultAndroidManifestPath,
+  String resources: _kDefaultResourcesPath,
+  String outputFile: _kDefaultOutputPath,
+  String target: '',
+  String flxPath: '',
+  ApkKeystoreInfo keystore
+}) async {
+  if (!_needsRebuild(outputFile, manifest)) {
+    printTrace('APK up to date. Skipping build step.');
     return 0;
   }
 
-  @override
-  Future<int> runInProject() async {
-    BuildConfiguration config = buildConfigurations.firstWhere(
+  BuildConfiguration config = configs.firstWhere(
       (BuildConfiguration bc) => bc.targetPlatform == TargetPlatform.android
   );
-
-    _ApkComponents components = await _findApkComponents(config);
+  _ApkComponents components = await _findApkComponents(config, enginePath, manifest, resources);
   if (components == null) {
-      printError('Unable to build APK.');
+    printError('Failure building APK. Unable to find components.');
     return 1;
   }
 
-    String flxPath = argResults['flx'];
+  printStatus('Building APK...');
 
   if (!flxPath.isEmpty) {
     if (!FileSystemEntity.isFileSync(flxPath)) {
@@ -385,21 +488,56 @@ class ApkCommand extends FlutterCommand {
       printError('(Omit the --flx option to build the FLX automatically)');
       return 1;
     }
-      return _buildApk(components, flxPath);
+    return _buildApk(components, flxPath, keystore, outputFile);
   } else {
-      await downloadToolchain();
-
     // Find the path to the main Dart file.
-      String mainPath = findMainDartFile(argResults['target']);
+    String mainPath = findMainDartFile(target);
 
     // Build the FLX.
     flx.DirectoryResult buildResult = await flx.buildInTempDir(toolchain, mainPath: mainPath);
 
     try {
-        return _buildApk(components, buildResult.localBundlePath);
+      return _buildApk(components, buildResult.localBundlePath, keystore, outputFile);
     } finally {
       buildResult.dispose();
     }
   }
+}
+
+Future<ApplicationPackageStore> buildAll(
+  DeviceStore devices,
+  ApplicationPackageStore applicationPackages,
+  Toolchain toolchain,
+  List<BuildConfiguration> configs, {
+  String enginePath,
+  String target: ''
+}) async {
+  for (Device device in devices.all) {
+    ApplicationPackage package = applicationPackages.getPackageForPlatform(device.platform);
+    if (package == null || !device.isConnected())
+      continue;
+
+    // TODO(mpcomplete): Temporary hack. We only support the apk builder atm.
+    if (package == applicationPackages.android) {
+      if (!FileSystemEntity.isFileSync(_kDefaultAndroidManifestPath)) {
+        printStatus('Using pre-built SkyShell.apk');
+        continue;
+      }
+
+      await buildAndroid(
+        toolchain: toolchain,
+        configs: configs,
+        enginePath: enginePath,
+        force: false,
+        target: target
+      );
+      // Replace our pre-built AndroidApk with this custom-built one.
+      applicationPackages = new ApplicationPackageStore(
+        android: _getApplicationPackage(_kDefaultOutputPath, _kDefaultAndroidManifestPath),
+        iOS: applicationPackages.iOS,
+        iOSSimulator: applicationPackages.iOSSimulator
+      );
+    }
   }
+  return applicationPackages;
 }

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

@@ -253,6 +253,7 @@ class AppDomain extends Domain {
         command.devices,
         command.applicationPackages,
         command.toolchain,
+        command.buildConfigurations,
         target: args['target'],
         route: args['route'],
         checked: args['checked'] ?? true

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

@@ -41,6 +41,7 @@ class ListenCommand extends StartCommandBase {
         devices,
         applicationPackages,
         toolchain,
+        buildConfigurations,
         target: argResults['target'],
         install: firstTime,
         stop: true,

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

@@ -10,9 +10,11 @@ import 'package:path/path.dart' as path;
 import '../application_package.dart';
 import '../base/common.dart';
 import '../base/context.dart';
+import '../build_configuration.dart';
 import '../device.dart';
 import '../runner/flutter_command.dart';
 import '../toolchain.dart';
+import 'apk.dart';
 import 'install.dart';
 import 'stop.dart';
 
@@ -92,7 +94,9 @@ class StartCommand extends StartCommandBase {
       devices,
       applicationPackages,
       toolchain,
+      buildConfigurations,
       target: argResults['target'],
+      enginePath: runner.enginePath,
       install: true,
       stop: argResults['full-restart'],
       checked: argResults['checked'],
@@ -111,8 +115,10 @@ class StartCommand extends StartCommandBase {
 Future<int> startApp(
   DeviceStore devices,
   ApplicationPackageStore applicationPackages,
-  Toolchain toolchain, {
+  Toolchain toolchain,
+  List<BuildConfiguration> configs, {
   String target,
+  String enginePath,
   bool stop: true,
   bool install: true,
   bool checked: true,
@@ -132,6 +138,14 @@ Future<int> startApp(
     return 1;
   }
 
+  if (install) {
+    printTrace('Running build command.');
+    applicationPackages = await buildAll(
+      devices, applicationPackages, toolchain, configs,
+      enginePath: enginePath,
+      target: target);
+  }
+
   if (stop) {
     printTrace('Running stop command.');
     stopAll(devices, applicationPackages);

packages/flutter_tools/lib/src/ios/device_ios.dart

@@ -614,7 +614,7 @@ class _IOSSimulatorLogReader extends DeviceLogReader {
       }
     );
 
-    return result;
+    return await result;
   }
 
   int get hashCode => device.logFilePath.hashCode;

packages/flutter_tools/pubspec.yaml

@@ -18,6 +18,7 @@ dependencies:
   stack_trace: ^1.4.0
   test: 0.12.6+1 # see note below
   yaml: ^2.1.3
+  xml: ^2.4.1
 
   flx:
     path: ../flx

packages/flutter_tools/test/listen_test.dart

@@ -4,6 +4,7 @@
 
 import 'package:args/command_runner.dart';
 import 'package:flutter_tools/src/commands/listen.dart';
+import 'package:flutter_tools/src/runner/flutter_command_runner.dart';
 import 'package:mockito/mockito.dart';
 import 'package:test/test.dart';
 
@@ -22,8 +23,7 @@ defineTests() {
       when(mockDevices.iOS.isConnected()).thenReturn(false);
       when(mockDevices.iOSSimulator.isConnected()).thenReturn(false);
 
-      CommandRunner runner = new CommandRunner('test_flutter', '')
-        ..addCommand(command);
+      CommandRunner runner = new FlutterCommandRunner()..addCommand(command);
       runner.run(['listen']).then((int code) => expect(code, equals(0)));
     });
   });