Refactor listen in terms of start.

Fixes #1034, at least for start and listen.

packages/flutter_tools/lib/src/base/process.dart

@@ -62,12 +62,14 @@ Future<Process> runDetached(List<String> cmd) {
 
 /// Run cmd and return stdout.
 /// Throws an error if cmd exits with a non-zero value.
-String runCheckedSync(List<String> cmd, { String workingDirectory }) =>
-    _runWithLoggingSync(cmd, workingDirectory: workingDirectory, checked: true);
+String runCheckedSync(List<String> cmd, { String workingDirectory }) {
+  return _runWithLoggingSync(cmd, workingDirectory: workingDirectory, checked: true);
+}
 
 /// Run cmd and return stdout.
-String runSync(List<String> cmd, { String workingDirectory }) =>
-    _runWithLoggingSync(cmd, workingDirectory: workingDirectory);
+String runSync(List<String> cmd, { String workingDirectory }) {
+  return _runWithLoggingSync(cmd, workingDirectory: workingDirectory);
+}
 
 /// Return the platform specific name for the given Dart SDK binary. So, `pub`
 /// ==> `pub.bat`.

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

@@ -252,7 +252,7 @@ class ApkCommand extends FlutterCommand {
       await downloadToolchain();
 
       // Find the path to the main Dart file.
-      String mainPath = StartCommand.findMainDartFile(argResults['target']);
+      String mainPath = StartCommandBase.findMainDartFile(argResults['target']);
 
       // Build the FLX.
       BuildCommand builder = new BuildCommand();

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

@@ -5,104 +5,67 @@
 import 'dart:async';
 import 'dart:io';
 
-import '../application_package.dart';
 import '../base/logging.dart';
 import '../base/process.dart';
-import '../device.dart';
-import '../runner/flutter_command.dart';
-import 'build.dart';
+import 'start.dart';
 
-class ListenCommand extends FlutterCommand {
+class ListenCommand extends StartCommandBase {
   final String name = 'listen';
-  final String description = 'Listen for changes to files and reload the running app on all connected devices.';
-  List<String> watchCommand;
+  final String description = 'Listen for changes to files and reload the running app on all connected devices. (Android only.)'
+      'By default, only listens to "./" and "./lib/". To listen to additional directories, list them on the command line.';
 
   /// Only run once.  Used for testing.
-  bool singleRun;
+  final bool singleRun;
 
-  ListenCommand({ this.singleRun: false }) {
-    argParser.addFlag('checked',
-        negatable: true,
-        defaultsTo: true,
-        help: 'Toggle Dart\'s checked mode.');
-    argParser.addOption('target',
-        defaultsTo: '.',
-        abbr: 't',
-        help: 'Target app path or filename to start.');
-  }
-
-  static const String _remoteFlutterBundle = 'Documents/app.flx';
+  ListenCommand({ this.singleRun: false });
 
   @override
   Future<int> runInProject() async {
     await downloadApplicationPackagesAndConnectToDevices();
     await downloadToolchain();
 
-    if (argResults.rest.length > 0) {
-      watchCommand = _initWatchCommand(argResults.rest);
-    } else {
-      watchCommand = _initWatchCommand(['.']);
-    }
+    List<String> watchCommand = _constructWatchCommand(() sync* {
+      yield* argResults.rest;
+      yield '.';
+      yield 'lib';
+    }());
 
-    while (true) {
+    int result = 0;
+    bool firstTime = true;
+    do {
       logging.info('Updating running Flutter apps...');
-
-      BuildCommand builder = new BuildCommand();
-      builder.inheritFromParent(this);
-      await builder.buildInTempDir(
-        onBundleAvailable: (String localBundlePath) {
-          for (Device device in devices.all) {
-            ApplicationPackage package = applicationPackages.getPackageForPlatform(device.platform);
-            if (package == null || !device.isConnected())
-              continue;
-            if (device is AndroidDevice) {
-              device.startBundle(package, localBundlePath, poke: true, checked: argResults['checked']);
-            } else if (device is IOSDevice) {
-              device.pushFile(package, localBundlePath, _remoteFlutterBundle);
-            } else if (device is IOSSimulator) {
-              // TODO(abarth): Move pushFile up to Device once Android supports
-              // pushing new bundles.
-              device.pushFile(package, localBundlePath, _remoteFlutterBundle);
-            } else {
-              assert(false);
-            }
-          }
-        }
-      );
-
-      if (singleRun || !watchDirectory())
-        break;
-    }
-
+      result = await startApp(install: firstTime, stop: true);
+      firstTime = false;
+    } while (!singleRun && result == 0 && _watchDirectory(watchCommand));
     return 0;
   }
 
-  List<String> _initWatchCommand(List<String> directories) {
+  List<String> _constructWatchCommand(Iterable<String> directories) {
     if (Platform.isMacOS) {
       try {
-        runCheckedSync(['which', 'fswatch']);
+        runCheckedSync(<String>['which', 'fswatch']);
       } catch (e) {
         logging.severe('"listen" command is only useful if you have installed '
             'fswatch on Mac.  Run "brew install fswatch" to install it with '
             'homebrew.');
         return null;
       }
-      return ['fswatch', '-r', '-v', '-1']..addAll(directories);
+      return <String>['fswatch', '-r', '-v', '-1']..addAll(directories);
     } else if (Platform.isLinux) {
       try {
-        runCheckedSync(['which', 'inotifywait']);
+        runCheckedSync(<String>['which', 'inotifywait']);
       } catch (e) {
         logging.severe('"listen" command is only useful if you have installed '
             'inotifywait on Linux.  Run "apt-get install inotify-tools" or '
             'equivalent to install it.');
         return null;
       }
-      return [
+      return <String>[
         'inotifywait',
         '-r',
         '-e',
         // Only listen for events that matter, to avoid triggering constantly
-        // from the editor watching files
+        // from the editor watching files.
         'modify,close_write,move,create,delete',
       ]..addAll(directories);
     } else {
@@ -111,17 +74,15 @@ class ListenCommand extends FlutterCommand {
     return null;
   }
 
-  bool watchDirectory() {
-    if (watchCommand == null)
-      return false;
-
+  bool _watchDirectory(List<String> watchCommand) {
+    logging.info('Attempting to listen to these directories: ${watchCommand.join(", ")}');
+    assert(watchCommand != null);
     try {
       runCheckedSync(watchCommand);
     } catch (e) {
       logging.warning('Watching directories failed.', e);
       return false;
     }
-
     return true;
   }
 }

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

@@ -154,7 +154,7 @@ class RunMojoCommand extends FlutterCommand {
     if (bundlePath == null) {
       bundlePath = _kDefaultBundlePath;
 
-      String mainPath = StartCommand.findMainDartFile(argResults['target']);
+      String mainPath = StartCommandBase.findMainDartFile(argResults['target']);
 
       BuildCommand builder = new BuildCommand();
       builder.inheritFromParent(this);

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

@@ -15,14 +15,10 @@ import 'build.dart';
 import 'install.dart';
 import 'stop.dart';
 
-class StartCommand extends FlutterCommand {
-  final String name = 'start';
-  final String description = 'Start your Flutter app on attached devices.';
+// We don't yet support iOS here. https://github.com/flutter/flutter/issues/1036
 
-  StartCommand() {
-    argParser.addFlag('poke',
-        negatable: false,
-        help: 'Restart the connection to the server (Android only).');
+abstract class StartCommandBase extends FlutterCommand {
+  StartCommandBase() {
     argParser.addFlag('checked',
         negatable: true,
         defaultsTo: true,
@@ -35,9 +31,8 @@ class StartCommand extends FlutterCommand {
         defaultsTo: '',
         abbr: 't',
         help: 'Target app path or filename to start.');
-    argParser.addOption('route', help: 'Which route to load when starting the app.');
-    argParser.addFlag('boot',
-        help: 'Boot the iOS Simulator if it isn\'t already running.');
+    argParser.addOption('route',
+        help: 'Which route to load when starting the app.');
   }
 
   /// Given the value of the --target option, return the path of the Dart file
@@ -51,29 +46,29 @@ class StartCommand extends FlutterCommand {
     }
   }
 
-  @override
-  Future<int> runInProject() async {
-    logging.fine('downloading toolchain');
-
-    await Future.wait([
-      downloadToolchain(),
-      downloadApplicationPackagesAndConnectToDevices(),
-    ]);
+  Future<int> startApp({ bool stop: true, bool install: true, bool poke: false }) async {
 
-    bool poke = argResults['poke'];
-    if (!poke) {
-      logging.fine('running stop command');
+    String mainPath = findMainDartFile(argResults['target']);
+    if (!FileSystemEntity.isFileSync(mainPath)) {
+      String message = 'Tried to run $mainPath, but that file does not exist.';
+      if (!argResults.wasParsed('target'))
+        message += '\nConsider using the -t option to specify that Dart file to start.';
+      logging.severe(message);
+      return 1;
+    }
 
+    if (stop) {
+      logging.fine('Running stop command.');
       StopCommand stopper = new StopCommand();
       stopper.inheritFromParent(this);
       stopper.stop();
-
-      logging.fine('running install command');
-
-      // Only install if the user did not specify a poke
+    }
+ 
+    if (install) {
+      logging.fine('Running install command.');
       InstallCommand installer = new InstallCommand();
       installer.inheritFromParent(this);
-      installer.install(boot: argResults['boot']);
+      installer.install();
     }
 
     bool startedSomething = false;
@@ -83,39 +78,22 @@ class StartCommand extends FlutterCommand {
       if (package == null || !device.isConnected())
         continue;
 
-      if (device is AndroidDevice) {
-        String mainPath = findMainDartFile(argResults['target']);
-        if (!FileSystemEntity.isFileSync(mainPath)) {
-          String message = 'Tried to run $mainPath, but that file does not exist.';
-          if (!argResults.wasParsed('target'))
-            message += '\nConsider using the -t option to specify that Dart file to start.';
-          stderr.writeln(message);
-          continue;
+      logging.fine('Running build command for $device.');
+      BuildCommand builder = new BuildCommand();
+      builder.inheritFromParent(this);
+      await builder.buildInTempDir(
+        mainPath: mainPath,
+        onBundleAvailable: (String localBundlePath) {
+          logging.fine('Starting bundle for $device.');
+          final AndroidDevice androidDevice = device; // https://github.com/flutter/flutter/issues/1035
+          if (androidDevice.startBundle(package, localBundlePath,
+                                        poke: poke,
+                                        checked: argResults['checked'],
+                                        traceStartup: argResults['trace-startup'],
+                                        route: argResults['route']))
+            startedSomething = true;
         }
-
-        logging.fine('running build command for $device');
-
-        BuildCommand builder = new BuildCommand();
-        builder.inheritFromParent(this);
-        await builder.buildInTempDir(
-          mainPath: mainPath,
-          onBundleAvailable: (String localBundlePath) {
-            logging.fine('running start bundle for $device');
-
-            if (device.startBundle(package, localBundlePath,
-                                   poke: poke,
-                                   checked: argResults['checked'],
-                                   traceStartup: argResults['trace-startup'],
-                                   route: argResults['route']))
-              startedSomething = true;
-          }
-        );
-      } else {
-        logging.fine('running start command for $device');
-
-        if (await device.startApp(package))
-          startedSomething = true;
-      }
+      );
     }
 
     if (!startedSomething) {
@@ -126,8 +104,35 @@ class StartCommand extends FlutterCommand {
       }
     }
 
-    logging.fine('finished start command');
-
     return startedSomething ? 0 : 2;
   }
 }
+
+class StartCommand extends StartCommandBase {
+  final String name = 'start';
+  final String description = 'Start your Flutter app on attached devices. (Android only.)';
+
+  StartCommand() {
+    argParser.addFlag('poke',
+        negatable: false,
+        help: 'Restart the connection to the server.');
+  }
+
+  @override
+  Future<int> runInProject() async {
+    logging.fine('Downloading toolchain.');
+
+    await Future.wait([
+      downloadToolchain(),
+      downloadApplicationPackagesAndConnectToDevices(),
+    ]);
+
+    bool poke = argResults['poke'];
+
+    // Only stop and reinstall if the user did not specify a poke
+    int result = await startApp(stop: !poke, install: !poke, poke: poke);
+
+    logging.fine('Finished start command.');
+    return result;
+  }
+}