Add a 'flutter ios --init' command that fetches the Xcode project from the cloud and configures it for a given flutter project

packages/flutter_tools/lib/executable.dart

@@ -17,6 +17,7 @@ import 'src/commands/cache.dart';
 import 'src/commands/daemon.dart';
 import 'src/commands/init.dart';
 import 'src/commands/install.dart';
+import 'src/commands/ios.dart';
 import 'src/commands/list.dart';
 import 'src/commands/listen.dart';
 import 'src/commands/logs.dart';
@@ -62,6 +63,7 @@ Future main(List<String> args) async {
     ..addCommand(new DaemonCommand())
     ..addCommand(new InitCommand())
     ..addCommand(new InstallCommand())
+    ..addCommand(new IOSCommand())
     ..addCommand(new ListCommand())
     ..addCommand(new ListenCommand())
     ..addCommand(new LogsCommand())

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

@@ -0,0 +1,155 @@
+// 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:io";
+
+import "package:path/path.dart" as path;
+
+import "../runner/flutter_command_runner.dart";
+import "../runner/flutter_command.dart";
+
+class IOSCommand extends FlutterCommand {
+  final String name = "ios";
+
+  final String description = "Commands for creating and updating Flutter iOS projects";
+
+  final bool requiresProjectRoot = true;
+
+  IOSCommand() {
+    argParser.addFlag('init', help: 'Initialize the Xcode project for building the iOS application');
+  }
+
+  static Uri _xcodeProjectUri(String revision) {
+    return Uri.parse("https://storage.googleapis.com/flutter_infra/flutter/${revision}/ios/FlutterXcode.zip");
+  }
+
+  Future<List<int>> _fetchXcodeArchive() async {
+    print("Fetching the Xcode project archive from the cloud...");
+
+    HttpClient client = new HttpClient();
+    // TODO(chinmaygarde): Currently, engine releases are not tied to the release of the Xcode project
+    // archive. So use a "Current" tag. This will need to be replaced once releases
+    // are in lockstep with the engine
+    HttpClientRequest request = await client.getUrl(_xcodeProjectUri("Current"));
+    HttpClientResponse response = await request.close();
+
+    if (response.statusCode != 200)
+      throw new Exception(response.reasonPhrase);
+
+    BytesBuilder bytesBuilder = new BytesBuilder(copy: false);
+    await for (List<int> chunk in response)
+      bytesBuilder.add(chunk);
+
+    return bytesBuilder.takeBytes();
+  }
+
+  Future<bool> _inflateXcodeArchive(String directory, List<int> archiveBytes) async {
+    print("Unzipping Xcode project to local directory...");
+
+    if (archiveBytes.isEmpty)
+      return false;
+
+    // We cannot use ArchiveFile because this archive contains file that are exectuable
+    // and there is currently no provision to modify file permissions during
+    // or after creation. See https://github.com/dart-lang/sdk/issues/15078
+    // So we depend on the platform to unzip the archive for us.
+
+    Directory tempDir = await Directory.systemTemp.create();
+    File tempFile = await new File(path.join(tempDir.path, "FlutterXcode.zip")).create();
+    IOSink writeSink = tempFile.openWrite();
+    writeSink.add(archiveBytes);
+    await writeSink.close();
+
+    ProcessResult result = await Process.run('/usr/bin/unzip', [tempFile.path, '-d', directory]);
+
+    // Cleanup the temp directory after unzipping
+    await Process.run('/bin/rm', ['rf', tempDir.path]);
+
+    if (result.exitCode != 0)
+      return false;
+
+    Directory flutterDir = new Directory(path.join(directory, 'Flutter'));
+    bool flutterDirExists = await flutterDir.exists();
+    if (!flutterDirExists)
+      return false;
+
+    // Move contents of the Flutter directory one level up
+    // There is no dart:io API to do this. See https://github.com/dart-lang/sdk/issues/8148
+
+    bool moveFailed = false;
+    for (FileSystemEntity file in flutterDir.listSync()) {
+      ProcessResult result = await Process.run('/bin/mv', [file.path, directory]);
+      moveFailed = result.exitCode != 0;
+      if (moveFailed)
+        break;
+    }
+
+    ProcessResult rmResult = await Process.run('/bin/rm', ["-rf", flutterDir.path]);
+
+    return !moveFailed && rmResult.exitCode == 0;
+  }
+
+  Future<bool> _setupXcodeProjXcconfig(String filePath) async {
+    StringBuffer localsBuffer = new StringBuffer();
+
+    localsBuffer.writeln("// Generated. Do not edit or check into version control!!");
+    localsBuffer.writeln("// Recreate using `flutter ios`");
+
+    String flutterRoot = path.normalize(Platform.environment[kFlutterRootEnvironmentVariableName]);
+    localsBuffer.writeln("FLUTTER_ROOT=${flutterRoot}");
+
+    // This holds because requiresProjectRoot is true for this command
+    String applicationRoot = path.normalize(Directory.current.path);
+    localsBuffer.writeln("FLUTTER_APPLICATION_PATH=${applicationRoot}");
+
+    String dartSDKPath = path.normalize(path.join(Platform.resolvedExecutable, "..", ".."));
+    localsBuffer.writeln("DART_SDK_PATH=${dartSDKPath}");
+
+    File localsFile = new File(filePath);
+    await localsFile.create(recursive: true);
+    await localsFile.writeAsString(localsBuffer.toString());
+
+    return true;
+  }
+
+  Future<int> _runInitCommand() async {
+    // Step 1: Fetch the archive from the cloud
+    String xcodeprojPath = path.join(Directory.current.path, "ios");
+    List<int> archiveBytes = await _fetchXcodeArchive();
+
+    // Step 2: Inflate the archive into the user project directory
+    bool result = await _inflateXcodeArchive(xcodeprojPath, archiveBytes);
+    if (!result) {
+      print("Could not fetch the Xcode project from the cloud...");
+      return -1;
+    }
+
+    // Step 3: Populate the Local.xcconfig with project specific paths
+    result = await _setupXcodeProjXcconfig(path.join(xcodeprojPath, "Local.xcconfig"));
+    if (!result) {
+      print("Could not setup local properties file");
+      return -1;
+    }
+
+    // Step 4: Launch Xcode and let the user edit plist, resources, provisioning, etc.
+    print("Launching project in Xcode...");
+    ProcessResult launch = await Process.run("/usr/bin/open", ["ios/FlutterApplication.xcodeproj"]);
+    return launch.exitCode;
+  }
+
+  @override
+  Future<int> runInProject() async {
+    if (!Platform.isMacOS) {
+      print("iOS specific commands may only be run on a Mac.");
+      return -1;
+    }
+
+    if (argResults['init'])
+      return _runInitCommand();
+
+    print("No flags specified...");
+    return -1;
+  }
+}