Reland: [flutter_tools] File system utilities (#48757)

* Reland: [flutter_tools] File system utilities

* Remove unused imports

packages/flutter_tools/lib/runner.dart

@@ -17,7 +17,6 @@ import 'src/base/io.dart';
 import 'src/base/logger.dart';
 import 'src/base/process.dart';
 import 'src/base/terminal.dart';
-import 'src/base/utils.dart';
 import 'src/context_runner.dart';
 import 'src/doctor.dart';
 import 'src/globals.dart' as globals;
@@ -191,7 +190,7 @@ FileSystem crashFileSystem = const LocalFileSystem();
 
 /// Saves the crash report to a local file.
 Future<File> _createLocalCrashReport(List<String> args, dynamic error, StackTrace stackTrace, String doctorText) async {
-  File crashFile = getUniqueFile(crashFileSystem.currentDirectory, 'flutter', 'log');
+  File crashFile = fsUtils.getUniqueFile(crashFileSystem.currentDirectory, 'flutter', 'log');
 
   final StringBuffer buffer = StringBuffer();
 
@@ -211,7 +210,7 @@ Future<File> _createLocalCrashReport(List<String> args, dynamic error, StackTrac
     crashFile.writeAsStringSync(buffer.toString());
   } on FileSystemException catch (_) {
     // Fallback to the system temporary directory.
-    crashFile = getUniqueFile(crashFileSystem.systemTempDirectory, 'flutter', 'log');
+    crashFile = fsUtils.getUniqueFile(crashFileSystem.systemTempDirectory, 'flutter', 'log');
     try {
       crashFile.writeAsStringSync(buffer.toString());
     } on FileSystemException catch (e) {

packages/flutter_tools/lib/src/android/gradle_utils.dart

@@ -98,7 +98,7 @@ class GradleUtils {
 
   /// Injects the Gradle wrapper files if any of these files don't exist in [directory].
   void injectGradleWrapperIfNeeded(Directory directory) {
-    copyDirectorySync(
+    fsUtils.copyDirectorySync(
       globals.cache.getArtifactDirectory('gradle_wrapper'),
       directory,
       shouldCopyFile: (File sourceFile, File destinationFile) {
@@ -267,10 +267,10 @@ void updateLocalProperties({
   }
 
   if (androidSdk != null) {
-    changeIfNecessary('sdk.dir', escapePath(androidSdk.directory));
+    changeIfNecessary('sdk.dir', fsUtils.escapePath(androidSdk.directory));
   }
 
-  changeIfNecessary('flutter.sdk', escapePath(Cache.flutterRoot));
+  changeIfNecessary('flutter.sdk', fsUtils.escapePath(Cache.flutterRoot));
   if (buildInfo != null) {
     changeIfNecessary('flutter.buildMode', buildInfo.modeName);
     final String buildName = validatedBuildNameForPlatform(
@@ -296,7 +296,7 @@ void updateLocalProperties({
 void writeLocalProperties(File properties) {
   final SettingsFile settings = SettingsFile();
   if (androidSdk != null) {
-    settings.values['sdk.dir'] = escapePath(androidSdk.directory);
+    settings.values['sdk.dir'] = fsUtils.escapePath(androidSdk.directory);
   }
   settings.writeContents(properties);
 }

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

@@ -11,7 +11,10 @@ import 'utils.dart';
 class Config {
   Config([File configFile, Logger localLogger]) {
     final Logger loggerInstance = localLogger ?? globals.logger;
-    _configFile = configFile ?? globals.fs.file(globals.fs.path.join(userHomePath(), '.flutter_settings'));
+    _configFile = configFile ?? globals.fs.file(globals.fs.path.join(
+      fsUtils.userHomePath,
+      '.flutter_settings',
+    ));
     if (_configFile.existsSync()) {
       try {
         _values = castStringKeyedMap(json.decode(_configFile.readAsStringSync()));

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

@@ -4,108 +4,149 @@
 
 import 'package:file/file.dart';
 import 'package:meta/meta.dart';
+import 'package:platform/platform.dart';
 
 import '../globals.dart' as globals;
 import 'common.dart' show throwToolExit;
+import 'context.dart';
 
 export 'package:file/file.dart';
 export 'package:file/local.dart';
 
-/// Create the ancestor directories of a file path if they do not already exist.
-void ensureDirectoryExists(String filePath) {
-  final String dirPath = globals.fs.path.dirname(filePath);
-  if (globals.fs.isDirectorySync(dirPath)) {
-    return;
-  }
-  try {
-    globals.fs.directory(dirPath).createSync(recursive: true);
-  } on FileSystemException catch (e) {
-    throwToolExit('Failed to create directory "$dirPath": ${e.osError.message}');
-  }
+/// Exception indicating that a file that was expected to exist was not found.
+class FileNotFoundException implements IOException {
+  const FileNotFoundException(this.path);
+
+  final String path;
+
+  @override
+  String toString() => 'File not found: $path';
 }
 
-/// Creates `destDir` if needed, then recursively copies `srcDir` to `destDir`,
-/// invoking [onFileCopied], if specified, for each source/destination file pair.
-///
-/// Skips files if [shouldCopyFile] returns `false`.
-void copyDirectorySync(
-  Directory srcDir,
-  Directory destDir, {
-  bool shouldCopyFile(File srcFile, File destFile),
-  void onFileCopied(File srcFile, File destFile),
-}) {
-  if (!srcDir.existsSync()) {
-    throw Exception('Source directory "${srcDir.path}" does not exist, nothing to copy');
-  }
+final FileSystemUtils _defaultFileSystemUtils = FileSystemUtils(
+  fileSystem: globals.fs,
+  platform: globals.platform,
+);
+
+FileSystemUtils get fsUtils => context.get<FileSystemUtils>() ?? _defaultFileSystemUtils;
+
+/// Various convenience file system methods.
+class FileSystemUtils {
+  FileSystemUtils({
+    @required FileSystem fileSystem,
+    @required Platform platform,
+  }) : _fileSystem = fileSystem,
+       _platform = platform;
+
+  final FileSystem _fileSystem;
+
+  final Platform _platform;
 
-  if (!destDir.existsSync()) {
-    destDir.createSync(recursive: true);
+  /// Create the ancestor directories of a file path if they do not already exist.
+  void ensureDirectoryExists(String filePath) {
+    final String dirPath = _fileSystem.path.dirname(filePath);
+    if (_fileSystem.isDirectorySync(dirPath)) {
+      return;
+    }
+    try {
+      _fileSystem.directory(dirPath).createSync(recursive: true);
+    } on FileSystemException catch (e) {
+      throwToolExit('Failed to create directory "$dirPath": ${e.osError.message}');
+    }
   }
 
-  for (final FileSystemEntity entity in srcDir.listSync()) {
-    final String newPath = destDir.fileSystem.path.join(destDir.path, entity.basename);
-    if (entity is File) {
-      final File newFile = destDir.fileSystem.file(newPath);
-      if (shouldCopyFile != null && !shouldCopyFile(entity, newFile)) {
-        continue;
+  /// Creates `destDir` if needed, then recursively copies `srcDir` to
+  /// `destDir`, invoking [onFileCopied], if specified, for each
+  /// source/destination file pair.
+  ///
+  /// Skips files if [shouldCopyFile] returns `false`.
+  void copyDirectorySync(
+    Directory srcDir,
+    Directory destDir, {
+    bool shouldCopyFile(File srcFile, File destFile),
+    void onFileCopied(File srcFile, File destFile),
+  }) {
+    if (!srcDir.existsSync()) {
+      throw Exception('Source directory "${srcDir.path}" does not exist, nothing to copy');
+    }
+
+    if (!destDir.existsSync()) {
+      destDir.createSync(recursive: true);
+    }
+
+    for (final FileSystemEntity entity in srcDir.listSync()) {
+      final String newPath = destDir.fileSystem.path.join(destDir.path, entity.basename);
+      if (entity is File) {
+        final File newFile = destDir.fileSystem.file(newPath);
+        if (shouldCopyFile != null && !shouldCopyFile(entity, newFile)) {
+          continue;
+        }
+        newFile.writeAsBytesSync(entity.readAsBytesSync());
+        onFileCopied?.call(entity, newFile);
+      } else if (entity is Directory) {
+        copyDirectorySync(
+          entity,
+          destDir.fileSystem.directory(newPath),
+          shouldCopyFile: shouldCopyFile,
+          onFileCopied: onFileCopied,
+        );
+      } else {
+        throw Exception('${entity.path} is neither File nor Directory');
       }
-      newFile.writeAsBytesSync(entity.readAsBytesSync());
-      onFileCopied?.call(entity, newFile);
-    } else if (entity is Directory) {
-      copyDirectorySync(
-        entity,
-        destDir.fileSystem.directory(newPath),
-        shouldCopyFile: shouldCopyFile,
-        onFileCopied: onFileCopied,
-      );
-    } else {
-      throw Exception('${entity.path} is neither File nor Directory');
     }
   }
-}
 
-/// Canonicalizes [path].
-///
-/// This function implements the behavior of `canonicalize` from
-/// `package:path`. However, unlike the original, it does not change the ASCII
-/// case of the path. Changing the case can break hot reload in some situations,
-/// for an example see: https://github.com/flutter/flutter/issues/9539.
-String canonicalizePath(String path) => globals.fs.path.normalize(globals.fs.path.absolute(path));
-
-/// Escapes [path].
-///
-/// On Windows it replaces all '\' with '\\'. On other platforms, it returns the
-/// path unchanged.
-String escapePath(String path) => globals.platform.isWindows ? path.replaceAll('\\', '\\\\') : path;
-
-/// Returns true if the file system [entity] has not been modified since the
-/// latest modification to [referenceFile].
-///
-/// Returns true, if [entity] does not exist.
-///
-/// Returns false, if [entity] exists, but [referenceFile] does not.
-bool isOlderThanReference({ @required FileSystemEntity entity, @required File referenceFile }) {
-  if (!entity.existsSync()) {
-    return true;
+  /// Appends a number to a filename in order to make it unique under a
+  /// directory.
+  File getUniqueFile(Directory dir, String baseName, String ext) {
+    final FileSystem fs = dir.fileSystem;
+    int i = 1;
+
+    while (true) {
+      final String name = '${baseName}_${i.toString().padLeft(2, '0')}.$ext';
+      final File file = fs.file(_fileSystem.path.join(dir.path, name));
+      if (!file.existsSync()) {
+        return file;
+      }
+      i++;
+    }
   }
-  return referenceFile.existsSync()
-      && referenceFile.statSync().modified.isAfter(entity.statSync().modified);
-}
 
-/// Exception indicating that a file that was expected to exist was not found.
-class FileNotFoundException implements IOException {
-  const FileNotFoundException(this.path);
+  /// Return a relative path if [fullPath] is contained by the cwd, else return an
+  /// absolute path.
+  String getDisplayPath(String fullPath) {
+    final String cwd = _fileSystem.currentDirectory.path + _fileSystem.path.separator;
+    return fullPath.startsWith(cwd) ? fullPath.substring(cwd.length) : fullPath;
+  }
 
-  final String path;
+  /// Escapes [path].
+  ///
+  /// On Windows it replaces all '\' with '\\'. On other platforms, it returns the
+  /// path unchanged.
+  String escapePath(String path) => _platform.isWindows ? path.replaceAll('\\', '\\\\') : path;
 
-  @override
-  String toString() => 'File not found: $path';
-}
+  /// Returns true if the file system [entity] has not been modified since the
+  /// latest modification to [referenceFile].
+  ///
+  /// Returns true, if [entity] does not exist.
+  ///
+  /// Returns false, if [entity] exists, but [referenceFile] does not.
+  bool isOlderThanReference({
+    @required FileSystemEntity entity,
+    @required File referenceFile,
+  }) {
+    if (!entity.existsSync()) {
+      return true;
+    }
+    return referenceFile.existsSync()
+        && referenceFile.statSync().modified.isAfter(entity.statSync().modified);
+  }
 
-/// Reads the process environment to find the current user's home directory.
-///
-/// If the searched environment variables are not set, '.' is returned instead.
-String userHomePath() {
-  final String envKey = globals.platform.operatingSystem == 'windows' ? 'APPDATA' : 'HOME';
-  return globals.platform.environment[envKey] ?? '.';
+  /// Reads the process environment to find the current user's home directory.
+  ///
+  /// If the searched environment variables are not set, '.' is returned instead.
+  String get userHomePath {
+    final String envKey = _platform.operatingSystem == 'windows' ? 'APPDATA' : 'HOME';
+    return _platform.environment[envKey] ?? '.';
+  }
 }

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

@@ -33,6 +33,7 @@ import 'dart:io' as io
     InternetAddressType,
     IOSink,
     NetworkInterface,
+    pid,
     Process,
     ProcessInfo,
     ProcessSignal,
@@ -252,6 +253,14 @@ Stream<List<int>> get stdin => globals.stdio.stdin;
 io.IOSink get stderr => globals.stdio.stderr;
 bool get stdinHasTerminal => globals.stdio.stdinHasTerminal;
 
+// TODO(zra): Move pid and writePidFile into `ProcessInfo`.
+void writePidFile(String pidFile) {
+  if (pidFile != null) {
+    // Write our pid to the file.
+    globals.fs.file(pidFile).writeAsStringSync(io.pid.toString());
+  }
+}
+
 /// An overridable version of io.ProcessInfo.
 abstract class ProcessInfo {
   factory ProcessInfo() => _DefaultProcessInfo();

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

@@ -9,9 +9,7 @@ import 'package:intl/intl.dart';
 import 'package:meta/meta.dart';
 
 import '../convert.dart';
-import '../globals.dart' as globals;
 import 'file_system.dart';
-import 'io.dart' as io;
 import 'terminal.dart';
 
 /// Convert `foo_bar` to `fooBar`.
@@ -51,29 +49,10 @@ String getEnumName(dynamic enumItem) {
   return index == -1 ? name : name.substring(index + 1);
 }
 
-File getUniqueFile(Directory dir, String baseName, String ext) {
-  final FileSystem fs = dir.fileSystem;
-  int i = 1;
-
-  while (true) {
-    final String name = '${baseName}_${i.toString().padLeft(2, '0')}.$ext';
-    final File file = fs.file(globals.fs.path.join(dir.path, name));
-    if (!file.existsSync()) {
-      return file;
-    }
-    i++;
-  }
-}
-
 String toPrettyJson(Object jsonable) {
   return const JsonEncoder.withIndent('  ').convert(jsonable) + '\n';
 }
 
-/// Return a String - with units - for the size in MB of the given number of bytes.
-String getSizeAsMB(int bytesLength) {
-  return '${(bytesLength / (1024 * 1024)).toStringAsFixed(1)}MB';
-}
-
 final NumberFormat kSecondsFormat = NumberFormat('0.0');
 final NumberFormat kMillisecondsFormat = NumberFormat.decimalPattern();
 
@@ -86,11 +65,9 @@ String getElapsedAsMilliseconds(Duration duration) {
   return '${kMillisecondsFormat.format(duration.inMilliseconds)}ms';
 }
 
-/// Return a relative path if [fullPath] is contained by the cwd, else return an
-/// absolute path.
-String getDisplayPath(String fullPath) {
-  final String cwd = globals.fs.currentDirectory.path + globals.fs.path.separator;
-  return fullPath.startsWith(cwd) ? fullPath.substring(cwd.length) : fullPath;
+/// Return a String - with units - for the size in MB of the given number of bytes.
+String getSizeAsMB(int bytesLength) {
+  return '${(bytesLength / (1024 * 1024)).toStringAsFixed(1)}MB';
 }
 
 /// A class to maintain a list of items, fire events when items are added or
@@ -315,13 +292,6 @@ String wrapText(String text, { int columnWidth, int hangingIndent, int indent, b
   return result.join('\n');
 }
 
-void writePidFile(String pidFile) {
-  if (pidFile != null) {
-    // Write our pid to the file.
-    globals.fs.file(pidFile).writeAsStringSync(io.pid.toString());
-  }
-}
-
 // Used to represent a run of ANSI control sequences next to a visible
 // character.
 class _AnsiRun {

packages/flutter_tools/lib/src/build_runner/resident_web_runner.dart

@@ -14,6 +14,7 @@ import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart'
 import '../application_package.dart';
 import '../base/async_guard.dart';
 import '../base/common.dart';
+import '../base/file_system.dart';
 import '../base/io.dart';
 import '../base/logger.dart';
 import '../base/net.dart';
@@ -388,7 +389,10 @@ class _ExperimentalResidentWebRunner extends ResidentWebRunner {
       return 1;
     }
     final String modeName = debuggingOptions.buildInfo.friendlyModeName;
-    globals.printStatus('Launching ${getDisplayPath(target)} on ${device.device.name} in $modeName mode...');
+    globals.printStatus(
+      'Launching ${fsUtils.getDisplayPath(target)} '
+      'on ${device.device.name} in $modeName mode...',
+    );
     final String effectiveHostname = debuggingOptions.hostname ?? 'localhost';
     final int hostPort = debuggingOptions.port == null
         ? await os.findFreePort()
@@ -587,7 +591,9 @@ class _DwdsResidentWebRunner extends ResidentWebRunner {
     }
     final String modeName = debuggingOptions.buildInfo.friendlyModeName;
     globals.printStatus(
-        'Launching ${getDisplayPath(target)} on ${device.device.name} in $modeName mode...');
+      'Launching ${fsUtils.getDisplayPath(target)} '
+      'on ${device.device.name} in $modeName mode...',
+    );
     Status buildStatus;
     bool statusActive = false;
     try {

packages/flutter_tools/lib/src/build_runner/web_compilation_delegate.dart

@@ -82,14 +82,23 @@ class BuildRunnerWebCompilationProxy extends WebCompilationProxy {
         .listSync()
         .whereType<Directory>();
       for (final Directory childDirectory in childDirectories) {
-        final String path = globals.fs.path.join(testOutputDir, 'packages',
-            globals.fs.path.basename(childDirectory.path));
-        copyDirectorySync(childDirectory.childDirectory('lib'), globals.fs.directory(path));
+        final String path = globals.fs.path.join(
+          testOutputDir,
+          'packages',
+          globals.fs.path.basename(childDirectory.path),
+        );
+        fsUtils.copyDirectorySync(
+          childDirectory.childDirectory('lib'),
+          globals.fs.directory(path),
+        );
       }
       final Directory outputDirectory = rootDirectory
-          .childDirectory(projectName)
-          .childDirectory('test');
-      copyDirectorySync(outputDirectory, globals.fs.directory(globals.fs.path.join(testOutputDir)));
+        .childDirectory(projectName)
+        .childDirectory('test');
+      fsUtils.copyDirectorySync(
+        outputDirectory,
+        globals.fs.directory(globals.fs.path.join(testOutputDir)),
+      );
     }
     return success;
   }

packages/flutter_tools/lib/src/build_system/targets/assets.dart

@@ -124,8 +124,8 @@ class FlutterPlugins extends Target {
     final FlutterProject project = FlutterProject.fromDirectory(environment.projectDir);
     final List<Plugin> plugins = findPlugins(project);
     final String pluginManifest = plugins
-        .map<String>((Plugin p) => '${p.name}=${escapePath(p.path)}')
-        .join('\n');
+      .map<String>((Plugin p) => '${p.name}=${fsUtils.escapePath(p.path)}')
+      .join('\n');
     final File flutterPluginsFile = environment.projectDir.childFile('.flutter-plugins');
     if (!flutterPluginsFile.existsSync() || flutterPluginsFile.readAsStringSync() != pluginManifest) {
       flutterPluginsFile.writeAsStringSync(pluginManifest);

packages/flutter_tools/lib/src/cache.dart

@@ -346,7 +346,10 @@ class Cache {
   /// [entity] doesn't exist.
   bool isOlderThanToolsStamp(FileSystemEntity entity) {
     final File flutterToolsStamp = getStampFileFor('flutter_tools');
-    return isOlderThanReference(entity: entity, referenceFile: flutterToolsStamp);
+    return fsUtils.isOlderThanReference(
+      entity: entity,
+      referenceFile: flutterToolsStamp,
+    );
   }
 
   bool isUpToDate() => _artifacts.every((ArtifactSet artifact) => artifact.isUpToDate());
@@ -912,7 +915,7 @@ class AndroidMavenArtifacts extends ArtifactSet {
       );
     try {
       final String gradleExecutable = gradle.absolute.path;
-      final String flutterSdk = escapePath(Cache.flutterRoot);
+      final String flutterSdk = fsUtils.escapePath(Cache.flutterRoot);
       final RunResult processResult = await processUtils.run(
         <String>[
           gradleExecutable,

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

@@ -11,7 +11,6 @@ import '../base/common.dart';
 import '../base/context.dart';
 import '../base/file_system.dart';
 import '../base/io.dart';
-import '../base/utils.dart';
 import '../cache.dart';
 import '../commands/daemon.dart';
 import '../compile.dart';

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

@@ -650,7 +650,7 @@ To edit platform code in an IDE see https://flutter.dev/developing-packages/#edi
 
   int _injectGradleWrapper(FlutterProject project) {
     int filesCreated = 0;
-    copyDirectorySync(
+    fsUtils.copyDirectorySync(
       globals.cache.getArtifactDirectory('gradle_wrapper'),
       project.android.hostAppGradleRoot,
       onFileCopied: (File sourceFile, File destinationFile) {

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

@@ -8,6 +8,7 @@ import 'package:args/command_runner.dart';
 
 import '../base/common.dart';
 import '../base/file_system.dart';
+import '../base/io.dart';
 import '../base/time.dart';
 import '../base/utils.dart';
 import '../build_info.dart';

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

@@ -6,7 +6,6 @@ import 'dart:async';
 
 import '../base/common.dart';
 import '../base/file_system.dart';
-import '../base/utils.dart';
 import '../convert.dart';
 import '../device.dart';
 import '../globals.dart' as globals;
@@ -110,7 +109,11 @@ class ScreenshotCommand extends FlutterCommand {
   }
 
   Future<void> runScreenshot(File outputFile) async {
-    outputFile ??= getUniqueFile(globals.fs.currentDirectory, 'flutter', 'png');
+    outputFile ??= fsUtils.getUniqueFile(
+      globals.fs.currentDirectory,
+      'flutter',
+      'png',
+    );
     try {
       await device.takeScreenshot(outputFile);
     } catch (error) {
@@ -121,7 +124,11 @@ class ScreenshotCommand extends FlutterCommand {
 
   Future<void> runSkia(File outputFile) async {
     final Map<String, dynamic> skp = await _invokeVmServiceRpc('_flutter.screenshotSkp');
-    outputFile ??= getUniqueFile(globals.fs.currentDirectory, 'flutter', 'skp');
+    outputFile ??= fsUtils.getUniqueFile(
+      globals.fs.currentDirectory,
+      'flutter',
+      'skp',
+    );
     final IOSink sink = outputFile.openWrite();
     sink.add(base64.decode(skp['skp'] as String));
     await sink.close();
@@ -131,7 +138,11 @@ class ScreenshotCommand extends FlutterCommand {
 
   Future<void> runRasterizer(File outputFile) async {
     final Map<String, dynamic> response = await _invokeVmServiceRpc('_flutter.screenshot');
-    outputFile ??= getUniqueFile(globals.fs.currentDirectory, 'flutter', 'png');
+    outputFile ??= fsUtils.getUniqueFile(
+      globals.fs.currentDirectory,
+      'flutter',
+      'png',
+    );
     final IOSink sink = outputFile.openWrite();
     sink.add(base64.decode(response['screenshot'] as String));
     await sink.close();

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

@@ -189,7 +189,7 @@ class ArtifactUnpacker {
         final String sourcePath = globals.fs.path.join(sourceDirectory, entityName);
         final String targetPath = globals.fs.path.join(targetDirectory, entityName);
         if (entityName.endsWith('/')) {
-          copyDirectorySync(
+          fsUtils.copyDirectorySync(
             globals.fs.directory(sourcePath),
             globals.fs.directory(targetPath),
           );

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

@@ -551,7 +551,10 @@ Future<XcodeBuildResult> buildXcodeProject({
         // (for example, kernel binary files produced from previous run).
         globals.fs.directory(outputDir).deleteSync(recursive: true);
       }
-      copyDirectorySync(globals.fs.directory(expectedOutputDirectory), globals.fs.directory(outputDir));
+      fsUtils.copyDirectorySync(
+        globals.fs.directory(expectedOutputDirectory),
+        globals.fs.directory(outputDir),
+      );
     } else {
       globals.printError('Build succeeded but the expected app at $expectedOutputDirectory not found');
     }

packages/flutter_tools/lib/src/persistent_tool_state.dart

@@ -25,7 +25,10 @@ abstract class PersistentToolState {
 
 class _DefaultPersistentToolState implements PersistentToolState {
   _DefaultPersistentToolState([File configFile]) :
-    _config = Config(configFile ?? globals.fs.file(globals.fs.path.join(userHomePath(), _kFileName)));
+    _config = Config(configFile ?? globals.fs.file(globals.fs.path.join(
+      fsUtils.userHomePath,
+      _kFileName,
+    )));
 
   static const String _kFileName = '.flutter_tool_state';
   static const String _kRedisplayWelcomeMessage = 'redisplay-welcome-message';

packages/flutter_tools/lib/src/plugins.dart

@@ -325,7 +325,7 @@ bool _writeFlutterPluginsList(FlutterProject project, List<Plugin> plugins) {
     pluginNames.add(plugin.name);
   }
   for (final Plugin plugin in plugins) {
-    flutterPluginsBuffer.write('${plugin.name}=${escapePath(plugin.path)}\n');
+    flutterPluginsBuffer.write('${plugin.name}=${fsUtils.escapePath(plugin.path)}\n');
     directAppDependencies.add(<String, dynamic>{
       'name': plugin.name,
       // Extract the plugin dependencies which happen to be plugins.

packages/flutter_tools/lib/src/project.dart

@@ -467,7 +467,10 @@ class IosProject implements XcodeBasedProject {
     if (!isModule) {
       return;
     }
-    final bool pubspecChanged = isOlderThanReference(entity: ephemeralDirectory, referenceFile: parent.pubspecFile);
+    final bool pubspecChanged = fsUtils.isOlderThanReference(
+      entity: ephemeralDirectory,
+      referenceFile: parent.pubspecFile,
+    );
     final bool toolingChanged = globals.cache.isOlderThanToolsStamp(ephemeralDirectory);
     if (!pubspecChanged && !toolingChanged) {
       return;
@@ -478,22 +481,37 @@ class IosProject implements XcodeBasedProject {
       .childDirectory('engine');
 
     _deleteIfExistsSync(ephemeralDirectory);
-    _overwriteFromTemplate(globals.fs.path.join('module', 'ios', 'library'), ephemeralDirectory);
+    _overwriteFromTemplate(
+      globals.fs.path.join('module', 'ios', 'library'),
+      ephemeralDirectory,
+    );
     // Add ephemeral host app, if a editable host app does not already exist.
     if (!_editableDirectory.existsSync()) {
-      _overwriteFromTemplate(globals.fs.path.join('module', 'ios', 'host_app_ephemeral'), ephemeralDirectory);
+      _overwriteFromTemplate(
+        globals.fs.path.join('module', 'ios', 'host_app_ephemeral'),
+        ephemeralDirectory,
+      );
       if (hasPlugins(parent)) {
-        _overwriteFromTemplate(globals.fs.path.join('module', 'ios', 'host_app_ephemeral_cocoapods'), ephemeralDirectory);
+        _overwriteFromTemplate(
+          globals.fs.path.join('module', 'ios', 'host_app_ephemeral_cocoapods'),
+          ephemeralDirectory,
+        );
       }
       // Copy podspec and framework from engine cache. The actual build mode
       // doesn't actually matter as it will be overwritten by xcode_backend.sh.
       // However, cocoapods will run before that script and requires something
       // to be in this location.
-      final Directory framework = globals.fs.directory(globals.artifacts.getArtifactPath(Artifact.flutterFramework,
-        platform: TargetPlatform.ios, mode: BuildMode.debug));
+      final Directory framework = globals.fs.directory(
+        globals.artifacts.getArtifactPath(Artifact.flutterFramework,
+        platform: TargetPlatform.ios,
+        mode: BuildMode.debug,
+      ));
       if (framework.existsSync()) {
         final File podspec = framework.parent.childFile('Flutter.podspec');
-        copyDirectorySync(framework, engineDest.childDirectory('Flutter.framework'));
+        fsUtils.copyDirectorySync(
+          framework,
+          engineDest.childDirectory('Flutter.framework'),
+        );
         podspec.copySync(engineDest.childFile('Flutter.podspec').path);
       }
     }
@@ -505,20 +523,36 @@ class IosProject implements XcodeBasedProject {
       throwToolExit('iOS host app is already editable. To start fresh, delete the ios/ folder.');
     }
     _deleteIfExistsSync(ephemeralDirectory);
-    _overwriteFromTemplate(globals.fs.path.join('module', 'ios', 'library'), ephemeralDirectory);
-    _overwriteFromTemplate(globals.fs.path.join('module', 'ios', 'host_app_ephemeral'), _editableDirectory);
-    _overwriteFromTemplate(globals.fs.path.join('module', 'ios', 'host_app_ephemeral_cocoapods'), _editableDirectory);
-    _overwriteFromTemplate(globals.fs.path.join('module', 'ios', 'host_app_editable_cocoapods'), _editableDirectory);
+    _overwriteFromTemplate(
+      globals.fs.path.join('module', 'ios', 'library'),
+      ephemeralDirectory,
+    );
+    _overwriteFromTemplate(
+      globals.fs.path.join('module', 'ios', 'host_app_ephemeral'),
+      _editableDirectory,
+    );
+    _overwriteFromTemplate(
+      globals.fs.path.join('module', 'ios', 'host_app_ephemeral_cocoapods'),
+      _editableDirectory,
+    );
+    _overwriteFromTemplate(
+      globals.fs.path.join('module', 'ios', 'host_app_editable_cocoapods'),
+      _editableDirectory,
+    );
     await _updateGeneratedXcodeConfigIfNeeded();
     await injectPlugins(parent);
   }
 
   @override
-  File get generatedXcodePropertiesFile => _flutterLibRoot.childDirectory('Flutter').childFile('Generated.xcconfig');
+  File get generatedXcodePropertiesFile => _flutterLibRoot
+    .childDirectory('Flutter')
+    .childFile('Generated.xcconfig');
 
   Directory get pluginRegistrantHost {
     return isModule
-        ? _flutterLibRoot.childDirectory('Flutter').childDirectory('FlutterPluginRegistrant')
+        ? _flutterLibRoot
+            .childDirectory('Flutter')
+            .childDirectory('FlutterPluginRegistrant')
         : hostAppRoot.childDirectory(_hostAppBundleName);
   }
 
@@ -632,8 +666,10 @@ class AndroidProject {
   }
 
   bool _shouldRegenerateFromTemplate() {
-    return isOlderThanReference(entity: ephemeralDirectory, referenceFile: parent.pubspecFile)
-        || globals.cache.isOlderThanToolsStamp(ephemeralDirectory);
+    return fsUtils.isOlderThanReference(
+      entity: ephemeralDirectory,
+      referenceFile: parent.pubspecFile,
+    ) || globals.cache.isOlderThanToolsStamp(ephemeralDirectory);
   }
 
   Future<void> makeHostAppEditable() async {

packages/flutter_tools/lib/src/resident_runner.dart

@@ -405,7 +405,10 @@ class FlutterDevice {
   }) async {
     final bool prebuiltMode = hotRunner.applicationBinary != null;
     final String modeName = hotRunner.debuggingOptions.buildInfo.friendlyModeName;
-    globals.printStatus('Launching ${getDisplayPath(hotRunner.mainPath)} on ${device.name} in $modeName mode...');
+    globals.printStatus(
+      'Launching ${fsUtils.getDisplayPath(hotRunner.mainPath)} '
+      'on ${device.name} in $modeName mode...',
+    );
 
     final TargetPlatform targetPlatform = await device.targetPlatform;
     package = await ApplicationPackageFactory.instance.getPackageForPlatform(
@@ -472,9 +475,15 @@ class FlutterDevice {
     final bool prebuiltMode = coldRunner.applicationBinary != null;
     if (coldRunner.mainPath == null) {
       assert(prebuiltMode);
-      globals.printStatus('Launching ${package.displayName} on ${device.name} in $modeName mode...');
+      globals.printStatus(
+        'Launching ${package.displayName} '
+        'on ${device.name} in $modeName mode...',
+      );
     } else {
-      globals.printStatus('Launching ${getDisplayPath(coldRunner.mainPath)} on ${device.name} in $modeName mode...');
+      globals.printStatus(
+        'Launching ${fsUtils.getDisplayPath(coldRunner.mainPath)} '
+        'on ${device.name} in $modeName mode...',
+      );
     }
 
     if (package == null) {
@@ -849,8 +858,15 @@ abstract class ResidentRunner {
   Future<void> screenshot(FlutterDevice device) async {
     assert(device.device.supportsScreenshot);
 
-    final Status status = globals.logger.startProgress('Taking screenshot for ${device.device.name}...', timeout: timeoutConfiguration.fastOperation);
-    final File outputFile = getUniqueFile(globals.fs.currentDirectory, 'flutter', 'png');
+    final Status status = globals.logger.startProgress(
+      'Taking screenshot for ${device.device.name}...',
+      timeout: timeoutConfiguration.fastOperation,
+    );
+    final File outputFile = fsUtils.getUniqueFile(
+      globals.fs.currentDirectory,
+      'flutter',
+      'png',
+    );
     try {
       if (supportsServiceProtocol && isRunningDebug) {
         await device.refreshViews();
@@ -881,7 +897,9 @@ abstract class ResidentRunner {
       }
       final int sizeKB = outputFile.lengthSync() ~/ 1024;
       status.stop();
-      globals.printStatus('Screenshot written to ${globals.fs.path.relative(outputFile.path)} (${sizeKB}kB).');
+      globals.printStatus(
+        'Screenshot written to ${globals.fs.path.relative(outputFile.path)} (${sizeKB}kB).',
+      );
     } catch (error) {
       status.cancel();
       globals.printError('Error taking screenshot: $error');

packages/flutter_tools/lib/src/test/test_compiler.dart

@@ -160,7 +160,7 @@ class TestCompiler {
           // The idea is to keep the cache file up-to-date and include as
           // much as possible in an effort to re-use as many packages as
           // possible.
-          ensureDirectoryExists(testFilePath);
+          fsUtils.ensureDirectoryExists(testFilePath);
           await outputFile.copy(testFilePath);
         }
         request.result.complete(kernelReadyToRun.path);

packages/flutter_tools/test/general.shard/base/file_system_test.dart

@@ -4,41 +4,41 @@
 
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
-import 'package:flutter_tools/src/globals.dart' as globals;
+import 'package:mockito/mockito.dart';
 import 'package:platform/platform.dart';
 
 import '../../src/common.dart';
-import '../../src/context.dart';
+
+class MockPlatform extends Mock implements Platform {}
 
 void main() {
   group('ensureDirectoryExists', () {
     MemoryFileSystem fs;
+    FileSystemUtils fsUtils;
 
     setUp(() {
       fs = MemoryFileSystem();
+      fsUtils = FileSystemUtils(
+        fileSystem: fs,
+        platform: MockPlatform(),
+      );
     });
 
-    testUsingContext('recursively creates a directory if it does not exist', () async {
-      ensureDirectoryExists('foo/bar/baz.flx');
+    testWithoutContext('recursively creates a directory if it does not exist', () async {
+      fsUtils.ensureDirectoryExists('foo/bar/baz.flx');
       expect(fs.isDirectorySync('foo/bar'), true);
-    }, overrides: <Type, Generator>{
-      FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager.any(),
     });
 
-    testUsingContext('throws tool exit on failure to create', () async {
+    testWithoutContext('throws tool exit on failure to create', () async {
       fs.file('foo').createSync();
-      expect(() => ensureDirectoryExists('foo/bar.flx'), throwsToolExit());
-    }, overrides: <Type, Generator>{
-      FileSystem: () => fs,
-      ProcessManager: () => FakeProcessManager.any(),
+      expect(() => fsUtils.ensureDirectoryExists('foo/bar.flx'), throwsToolExit());
     });
   });
 
   group('copyDirectorySync', () {
     /// Test file_systems.copyDirectorySync() using MemoryFileSystem.
     /// Copies between 2 instances of file systems which is also supported by copyDirectorySync().
-    test('test directory copy', () async {
+    testWithoutContext('test directory copy', () async {
       final MemoryFileSystem sourceMemoryFs = MemoryFileSystem();
       const String sourcePath = '/some/origin';
       final Directory sourceDirectory = await sourceMemoryFs.directory(sourcePath).create(recursive: true);
@@ -52,7 +52,12 @@ void main() {
       final MemoryFileSystem targetMemoryFs = MemoryFileSystem();
       const String targetPath = '/some/non-existent/target';
       final Directory targetDirectory = targetMemoryFs.directory(targetPath);
-      copyDirectorySync(sourceDirectory, targetDirectory);
+
+      final FileSystemUtils fsUtils = FileSystemUtils(
+        fileSystem: sourceMemoryFs,
+        platform: MockPlatform(),
+      );
+      fsUtils.copyDirectorySync(sourceDirectory, targetDirectory);
 
       expect(targetDirectory.existsSync(), true);
       targetMemoryFs.currentDirectory = targetPath;
@@ -66,16 +71,21 @@ void main() {
       expect(sourceMemoryFs.directory(sourcePath).listSync().length, 3);
     });
 
-    testUsingContext('Skip files if shouldCopyFile returns false', () {
-      final Directory origin = globals.fs.directory('/origin');
+    testWithoutContext('Skip files if shouldCopyFile returns false', () {
+      final MemoryFileSystem fileSystem = MemoryFileSystem();
+      final FileSystemUtils fsUtils = FileSystemUtils(
+        fileSystem: fileSystem,
+        platform: MockPlatform(),
+      );
+      final Directory origin = fileSystem.directory('/origin');
       origin.createSync();
-      globals.fs.file(globals.fs.path.join('origin', 'a.txt')).writeAsStringSync('irrelevant');
-      globals.fs.directory('/origin/nested').createSync();
-      globals.fs.file(globals.fs.path.join('origin', 'nested', 'a.txt')).writeAsStringSync('irrelevant');
-      globals.fs.file(globals.fs.path.join('origin', 'nested', 'b.txt')).writeAsStringSync('irrelevant');
+      fileSystem.file(fileSystem.path.join('origin', 'a.txt')).writeAsStringSync('irrelevant');
+      fileSystem.directory('/origin/nested').createSync();
+      fileSystem.file(fileSystem.path.join('origin', 'nested', 'a.txt')).writeAsStringSync('irrelevant');
+      fileSystem.file(fileSystem.path.join('origin', 'nested', 'b.txt')).writeAsStringSync('irrelevant');
 
-      final Directory destination = globals.fs.directory('/destination');
-      copyDirectorySync(origin, destination, shouldCopyFile: (File origin, File dest) {
+      final Directory destination = fileSystem.directory('/destination');
+      fsUtils.copyDirectorySync(origin, destination, shouldCopyFile: (File origin, File dest) {
         return origin.basename == 'b.txt';
       });
 
@@ -85,53 +95,30 @@ void main() {
 
       expect(destination.childFile('a.txt').existsSync(), isFalse);
       expect(destination.childDirectory('nested').childFile('a.txt').existsSync(), isFalse);
-    }, overrides: <Type, Generator>{
-      FileSystem: () => MemoryFileSystem(),
-      ProcessManager: () => FakeProcessManager.any(),
     });
   });
 
-  group('canonicalizePath', () {
-    test('does not lowercase on Windows', () {
-      String path = 'C:\\Foo\\bAr\\cOOL.dart';
-      expect(canonicalizePath(path), path);
-      // globals.fs.path.canonicalize does lowercase on Windows
-      expect(globals.fs.path.canonicalize(path), isNot(path));
-
-      path = '..\\bar\\.\\\\Foo';
-      final String expected = globals.fs.path.join(globals.fs.currentDirectory.parent.absolute.path, 'bar', 'Foo');
-      expect(canonicalizePath(path), expected);
-      // globals.fs.path.canonicalize should return the same result (modulo casing)
-      expect(globals.fs.path.canonicalize(path), expected.toLowerCase());
-    }, testOn: 'windows');
-
-    test('does not lowercase on posix', () {
-      String path = '/Foo/bAr/cOOL.dart';
-      expect(canonicalizePath(path), path);
-      // globals.fs.path.canonicalize and canonicalizePath should be the same on Posix
-      expect(globals.fs.path.canonicalize(path), path);
-
-      path = '../bar/.//Foo';
-      final String expected = globals.fs.path.join(globals.fs.currentDirectory.parent.absolute.path, 'bar', 'Foo');
-      expect(canonicalizePath(path), expected);
-    }, testOn: 'posix');
-  });
-
   group('escapePath', () {
-    testUsingContext('on Windows', () {
-      expect(escapePath('C:\\foo\\bar\\cool.dart'), 'C:\\\\foo\\\\bar\\\\cool.dart');
-      expect(escapePath('foo\\bar\\cool.dart'), 'foo\\\\bar\\\\cool.dart');
-      expect(escapePath('C:/foo/bar/cool.dart'), 'C:/foo/bar/cool.dart');
-    }, overrides: <Type, Generator>{
-      Platform: () => FakePlatform(operatingSystem: 'windows'),
+    testWithoutContext('on Windows', () {
+      final MemoryFileSystem fileSystem = MemoryFileSystem();
+      final FileSystemUtils fsUtils = FileSystemUtils(
+        fileSystem: fileSystem,
+        platform: FakePlatform(operatingSystem: 'windows'),
+      );
+      expect(fsUtils.escapePath('C:\\foo\\bar\\cool.dart'), 'C:\\\\foo\\\\bar\\\\cool.dart');
+      expect(fsUtils.escapePath('foo\\bar\\cool.dart'), 'foo\\\\bar\\\\cool.dart');
+      expect(fsUtils.escapePath('C:/foo/bar/cool.dart'), 'C:/foo/bar/cool.dart');
     });
 
-    testUsingContext('on Linux', () {
-      expect(escapePath('/foo/bar/cool.dart'), '/foo/bar/cool.dart');
-      expect(escapePath('foo/bar/cool.dart'), 'foo/bar/cool.dart');
-      expect(escapePath('foo\\cool.dart'), 'foo\\cool.dart');
-    }, overrides: <Type, Generator>{
-      Platform: () => FakePlatform(operatingSystem: 'linux'),
+    testWithoutContext('on Linux', () {
+      final MemoryFileSystem fileSystem = MemoryFileSystem();
+      final FileSystemUtils fsUtils = FileSystemUtils(
+        fileSystem: fileSystem,
+        platform: FakePlatform(operatingSystem: 'linux'),
+      );
+      expect(fsUtils.escapePath('/foo/bar/cool.dart'), '/foo/bar/cool.dart');
+      expect(fsUtils.escapePath('foo/bar/cool.dart'), 'foo/bar/cool.dart');
+      expect(fsUtils.escapePath('foo\\cool.dart'), 'foo\\cool.dart');
     });
   });
 }