blob: 36fd063b2b49f6679ce552022372d2e468689392 [file] [log] [blame]
// Copyright 2013 The Flutter 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:convert';
import 'dart:io' as io;
import 'package:file/file.dart';
import 'package:http/http.dart' as http;
import 'package:meta/meta.dart';
import 'package:platform/platform.dart';
import 'common/core.dart';
import 'common/package_command.dart';
import 'common/process_runner.dart';
/// In theory this should be 8191, but in practice that was still resulting in
/// "The input line is too long" errors. This was chosen as a value that worked
/// in practice via trial and error, but may need to be adjusted based on
/// further experience.
const int windowsCommandLineMax = 8000;
/// This value is picked somewhat arbitrarily based on checking `ARG_MAX` on a
/// macOS and Linux machine. If anyone encounters a lower limit in pratice, it
/// can be lowered accordingly.
const int nonWindowsCommandLineMax = 1000000;
const int _exitClangFormatFailed = 3;
const int _exitFlutterFormatFailed = 4;
const int _exitJavaFormatFailed = 5;
const int _exitGitFailed = 6;
const int _exitDependencyMissing = 7;
final Uri _googleFormatterUrl = Uri.https('',
/// A command to format all package code.
class FormatCommand extends PackageCommand {
/// Creates an instance of the format command.
Directory packagesDir, {
ProcessRunner processRunner = const ProcessRunner(),
Platform platform = const LocalPlatform(),
}) : super(packagesDir, processRunner: processRunner, platform: platform) {
argParser.addFlag('fail-on-change', hide: true);
defaultsTo: 'clang-format', help: 'Path to "clang-format" executable.');
defaultsTo: 'java', help: 'Path to "java" executable.');
final String name = 'format';
final String description =
'Formats the code of all packages (Java, Objective-C, C++, and Dart).\n\n'
'This command requires "git", "flutter" and "clang-format" v5 to be in '
'your path.';
Future<void> run() async {
final String googleFormatterPath = await _getGoogleFormatterPath();
// This class is not based on PackageLoopingCommand because running the
// formatters separately for each package is an order of magnitude slower,
// due to the startup overhead of the formatters.
final Iterable<String> files =
await _getFilteredFilePaths(getFiles(), relativeTo: packagesDir);
await _formatDart(files);
await _formatJava(files, googleFormatterPath);
await _formatCppAndObjectiveC(files);
if (getBoolArg('fail-on-change')) {
final bool modified = await _didModifyAnything();
if (modified) {
throw ToolExit(exitCommandFoundErrors);
Future<bool> _didModifyAnything() async {
final io.ProcessResult modifiedFiles = await
<String>['ls-files', '--modified'],
workingDir: packagesDir,
logOnError: true,
if (modifiedFiles.exitCode != 0) {
printError('Unable to determine changed files.');
throw ToolExit(_exitGitFailed);
final String stdout = modifiedFiles.stdout as String;
if (stdout.isEmpty) {
print('All files formatted correctly.');
return false;
print('These files are not formatted correctly (see diff below):');
LineSplitter.split(stdout).map((String line) => ' $line').forEach(print);
print('\nTo fix run "dart pub global activate flutter_plugin_tools && '
'dart pub global run flutter_plugin_tools format" or copy-paste '
'this command into your terminal:');
final io.ProcessResult diff = await
workingDir: packagesDir,
logOnError: true,
if (diff.exitCode != 0) {
printError('Unable to determine diff.');
throw ToolExit(_exitGitFailed);
print('patch -p1 <<DONE');
return true;
Future<void> _formatCppAndObjectiveC(Iterable<String> files) async {
final Iterable<String> clangFiles = _getPathsWithExtensions(
files, <String>{'.h', '.m', '.mm', '.cc', '.cpp'});
if (clangFiles.isNotEmpty) {
final String clangFormat = await _findValidClangFormat();
print('Formatting .cc, .cpp, .h, .m, and .mm files...');
final int exitCode = await _runBatched(
clangFormat, <String>['-i', '--style=file'],
files: clangFiles);
if (exitCode != 0) {
'Failed to format C, C++, and Objective-C files: exit code $exitCode.');
throw ToolExit(_exitClangFormatFailed);
Future<String> _findValidClangFormat() async {
final String clangFormatArg = getStringArg('clang-format');
if (await _hasDependency(clangFormatArg)) {
return clangFormatArg;
// There is a known issue where "chromium/depot_tools/clang-format"
// fails with "Problem while looking for clang-format in Chromium source tree".
// Loop through all "clang-format"s in PATH until a working one is found,
// for example "/usr/local/bin/clang-format" or a "brew" installed version.
for (final String clangFormatPath in await _whichAll('clang-format')) {
if (await _hasDependency(clangFormatPath)) {
return clangFormatPath;
printError('Unable to run "clang-format". Make sure that it is in your '
'path, or provide a full path with --clang-format.');
throw ToolExit(_exitDependencyMissing);
Future<void> _formatJava(
Iterable<String> files, String googleFormatterPath) async {
final Iterable<String> javaFiles =
_getPathsWithExtensions(files, <String>{'.java'});
if (javaFiles.isNotEmpty) {
final String java = getStringArg('java');
if (!await _hasDependency(java)) {
'Unable to run "java". Make sure that it is in your path, or '
'provide a full path with --java.');
throw ToolExit(_exitDependencyMissing);
print('Formatting .java files...');
final int exitCode = await _runBatched(
java, <String>['-jar', googleFormatterPath, '--replace'],
files: javaFiles);
if (exitCode != 0) {
printError('Failed to format Java files: exit code $exitCode.');
throw ToolExit(_exitJavaFormatFailed);
Future<void> _formatDart(Iterable<String> files) async {
final Iterable<String> dartFiles =
_getPathsWithExtensions(files, <String>{'.dart'});
if (dartFiles.isNotEmpty) {
print('Formatting .dart files...');
final int exitCode =
await _runBatched('dart', <String>['format'], files: dartFiles);
if (exitCode != 0) {
printError('Failed to format Dart files: exit code $exitCode.');
throw ToolExit(_exitFlutterFormatFailed);
/// Given a stream of [files], returns the paths of any that are not in known
/// locations to ignore, relative to [relativeTo].
Future<Iterable<String>> _getFilteredFilePaths(
Stream<File> files, {
required Directory relativeTo,
}) async {
// Returns a pattern to check for [directories] as a subset of a file path.
RegExp pathFragmentForDirectories(List<String> directories) {
String s = path.separator;
// Escape the separator for use in the regex.
if (s == r'\') {
s = r'\\';
return RegExp('(?:^|$s)${path.joinAll(directories)}$s');
final String fromPath = relativeTo.path;
// Dart files are allowed to have a pragma to disable auto-formatting. This
// was added because Hixie hurts when dealing with what dartfmt does to
// artisanally-formatted Dart, while Stuart gets really frustrated when
// dealing with PRs from newer contributors who don't know how to make Dart
// readable. After much discussion, it was decided that files in the plugins
// and packages repos that really benefit from hand-formatting (e.g. files
// with large blobs of hex literals) could be opted-out of the requirement
// that they be autoformatted, so long as the code's owner was willing to
// bear the cost of this during code reviews.
// In the event that code ownership moves to someone who does not hold the
// same views as the original owner, the pragma can be removed and the file
// auto-formatted.
const String handFormattedExtension = '.dart';
const String handFormattedPragma = '// This file is hand-formatted.';
return files
.where((File file) {
// See comment above near [handFormattedPragma].
return path.extension(file.path) != handFormattedExtension ||
.map((File file) => path.relative(file.path, from: fromPath))
.where((String path) =>
// Ignore files in build/ directories (e.g., headers of frameworks)
// to avoid useless extra work in local repositories.
pathFragmentForDirectories(<String>['example', 'build'])) &&
// Ignore files in Pods, which are not part of the repository.
!path.contains(pathFragmentForDirectories(<String>['Pods'])) &&
// Ignore .dart_tool/, which can have various intermediate files.
Iterable<String> _getPathsWithExtensions(
Iterable<String> files, Set<String> extensions) {
return files.where(
(String filePath) => extensions.contains(path.extension(filePath)));
Future<String> _getGoogleFormatterPath() async {
final String javaFormatterPath = path.join(
final File javaFormatterFile =
if (!javaFormatterFile.existsSync()) {
print('Downloading Google Java Format...');
final http.Response response = await http.get(_googleFormatterUrl);
return javaFormatterPath;
/// Returns true if [command] can be run successfully.
Future<bool> _hasDependency(String command) async {
// Some versions of Java accept both -version and --version, but some only
// accept -version.
final String versionFlag = command == 'java' ? '-version' : '--version';
try {
final io.ProcessResult result =
await, <String>[versionFlag]);
if (result.exitCode != 0) {
return false;
} on io.ProcessException {
// Thrown when the binary is missing entirely.
return false;
return true;
/// Returns all instances of [command] executable found on user path.
Future<List<String>> _whichAll(String command) async {
try {
final io.ProcessResult result =
await'which', <String>['-a', command]);
if (result.exitCode != 0) {
return <String>[];
final String stdout = (result.stdout as String).trim();
if (stdout.isEmpty) {
return <String>[];
return LineSplitter.split(stdout).toList();
} on io.ProcessException {
return <String>[];
/// Runs [command] on [arguments] on all of the files in [files], batched as
/// necessary to avoid OS command-line length limits.
/// Returns the exit code of the first failure, which stops the run, or 0
/// on success.
Future<int> _runBatched(
String command,
List<String> arguments, {
required Iterable<String> files,
}) async {
final int commandLineMax =
platform.isWindows ? windowsCommandLineMax : nonWindowsCommandLineMax;
// Compute the max length of the file argument portion of a batch.
// Add one to each argument's length for the space before it.
final int argumentTotalLength =
arguments.fold(0, (int sum, String arg) => sum + arg.length + 1);
final int batchMaxTotalLength =
commandLineMax - command.length - argumentTotalLength;
// Run the command in batches.
final List<List<String>> batches =
_partitionFileList(files, maxStringLength: batchMaxTotalLength);
for (final List<String> batch in batches) {
batch.sort(); // For ease of testing.
final int exitCode = await processRunner.runAndStream(
command, <String>[...arguments, ...batch],
workingDir: packagesDir);
if (exitCode != 0) {
return exitCode;
return 0;
/// Partitions [files] into batches whose max string length as parameters to
/// a command (including the spaces between them, and between the list and
/// the command itself) is no longer than [maxStringLength].
List<List<String>> _partitionFileList(Iterable<String> files,
{required int maxStringLength}) {
final List<List<String>> batches = <List<String>>[<String>[]];
int currentBatchTotalLength = 0;
for (final String file in files) {
final int length = file.length + 1 /* for the space */;
if (currentBatchTotalLength + length > maxStringLength) {
// Start a new batch.
currentBatchTotalLength = 0;
currentBatchTotalLength += length;
return batches;