Fix newly enforced package:pedantic lints (flutter#78)

- always_declare_return_types
- annotate_overrides
- prefer_collection_literals
- prefer_conditional_assignment
- prefer_final_fields
- prefer_if_null_operators
- prefer_single_quotes
- use_function_type_syntax_for_parameters

Bump min SDK to 2.2.0 to allow Set literals.

Author: natebosch

.travis.yml

@@ -2,7 +2,7 @@ language: dart
 
 dart:
 - dev
-- 2.0.0
+- 2.2.0
 
 dart_task:
 - test

benchmark/path_set.dart

@@ -13,11 +13,11 @@ import 'package:path/path.dart' as p;
 
 import 'package:watcher/src/path_set.dart';
 
-final String root = Platform.isWindows ? r"C:\root" : "/root";
+final String root = Platform.isWindows ? r'C:\root' : '/root';
 
 /// Base class for benchmarks on [PathSet].
 abstract class PathSetBenchmark extends BenchmarkBase {
-  PathSetBenchmark(String method) : super("PathSet.$method");
+  PathSetBenchmark(String method) : super('PathSet.$method');
 
   final PathSet pathSet = PathSet(root);
 
@@ -30,14 +30,14 @@ abstract class PathSetBenchmark extends BenchmarkBase {
   ///
   /// Each virtual directory contains ten entries: either subdirectories or
   /// files.
-  void walkTree(int depth, callback(String path)) {
-    recurse(String path, remainingDepth) {
+  void walkTree(int depth, void Function(String) callback) {
+    void recurse(String path, remainingDepth) {
       for (var i = 0; i < 10; i++) {
         var padded = i.toString().padLeft(2, '0');
         if (remainingDepth == 0) {
-          callback(p.join(path, "file_$padded.txt"));
+          callback(p.join(path, 'file_$padded.txt'));
         } else {
-          var subdir = p.join(path, "subdirectory_$padded");
+          var subdir = p.join(path, 'subdirectory_$padded');
           recurse(subdir, remainingDepth - 1);
         }
       }
@@ -48,16 +48,18 @@ abstract class PathSetBenchmark extends BenchmarkBase {
 }
 
 class AddBenchmark extends PathSetBenchmark {
-  AddBenchmark() : super("add()");
+  AddBenchmark() : super('add()');
 
   final List<String> paths = [];
 
+  @override
   void setup() {
     // Make a bunch of paths in about the same order we expect to get them from
     // Directory.list().
     walkTree(3, paths.add);
   }
 
+  @override
   void run() {
     for (var path in paths) {
       pathSet.add(path);
@@ -66,10 +68,11 @@ class AddBenchmark extends PathSetBenchmark {
 }
 
 class ContainsBenchmark extends PathSetBenchmark {
-  ContainsBenchmark() : super("contains()");
+  ContainsBenchmark() : super('contains()');
 
   final List<String> paths = [];
 
+  @override
   void setup() {
     // Add a bunch of paths to the set.
     walkTree(3, (path) {
@@ -80,48 +83,52 @@ class ContainsBenchmark extends PathSetBenchmark {
     // Add some non-existent paths to test the false case.
     for (var i = 0; i < 100; i++) {
       paths.addAll([
-        "/nope",
-        "/root/nope",
-        "/root/subdirectory_04/nope",
-        "/root/subdirectory_04/subdirectory_04/nope",
-        "/root/subdirectory_04/subdirectory_04/subdirectory_04/nope",
-        "/root/subdirectory_04/subdirectory_04/subdirectory_04/nope/file_04.txt",
+        '/nope',
+        '/root/nope',
+        '/root/subdirectory_04/nope',
+        '/root/subdirectory_04/subdirectory_04/nope',
+        '/root/subdirectory_04/subdirectory_04/subdirectory_04/nope',
+        '/root/subdirectory_04/subdirectory_04/subdirectory_04/nope/file_04.txt',
       ]);
     }
   }
 
+  @override
   void run() {
     var contained = 0;
     for (var path in paths) {
       if (pathSet.contains(path)) contained++;
     }
 
-    if (contained != 10000) throw "Wrong result: $contained";
+    if (contained != 10000) throw 'Wrong result: $contained';
   }
 }
 
 class PathsBenchmark extends PathSetBenchmark {
-  PathsBenchmark() : super("toSet()");
+  PathsBenchmark() : super('toSet()');
 
+  @override
   void setup() {
     walkTree(3, pathSet.add);
   }
 
+  @override
   void run() {
     var count = 0;
     for (var _ in pathSet.paths) {
       count++;
     }
 
-    if (count != 10000) throw "Wrong result: $count";
+    if (count != 10000) throw 'Wrong result: $count';
   }
 }
 
 class RemoveBenchmark extends PathSetBenchmark {
-  RemoveBenchmark() : super("remove()");
+  RemoveBenchmark() : super('remove()');
 
   final List<String> paths = [];
 
+  @override
   void setup() {
     // Make a bunch of paths. Do this here so that we don't spend benchmarked
     // time synthesizing paths.
@@ -136,14 +143,15 @@ class RemoveBenchmark extends PathSetBenchmark {
     paths.shuffle(random);
   }
 
+  @override
   void run() {
     for (var path in paths) {
       pathSet.remove(path);
     }
   }
 }
 
-main() {
+void main() {
   AddBenchmark().report();
   ContainsBenchmark().report();
   PathsBenchmark().report();

example/watch.dart

@@ -8,9 +8,9 @@ library watch;
 import 'package:path/path.dart' as p;
 import 'package:watcher/watcher.dart';
 
-main(List<String> arguments) {
+void main(List<String> arguments) {
   if (arguments.length != 1) {
-    print("Usage: watch <directory path>");
+    print('Usage: watch <directory path>');
     return;
   }
 

lib/src/constructable_file_system_event.dart

@@ -5,54 +5,67 @@
 import 'dart:io';
 
 abstract class _ConstructableFileSystemEvent implements FileSystemEvent {
+  @override
   final bool isDirectory;
+  @override
   final String path;
+  @override
   int get type;
 
   _ConstructableFileSystemEvent(this.path, this.isDirectory);
 }
 
 class ConstructableFileSystemCreateEvent extends _ConstructableFileSystemEvent
     implements FileSystemCreateEvent {
+  @override
   final type = FileSystemEvent.create;
 
   ConstructableFileSystemCreateEvent(String path, bool isDirectory)
       : super(path, isDirectory);
 
+  @override
   String toString() => "FileSystemCreateEvent('$path')";
 }
 
 class ConstructableFileSystemDeleteEvent extends _ConstructableFileSystemEvent
     implements FileSystemDeleteEvent {
+  @override
   final type = FileSystemEvent.delete;
 
   ConstructableFileSystemDeleteEvent(String path, bool isDirectory)
       : super(path, isDirectory);
 
+  @override
   String toString() => "FileSystemDeleteEvent('$path')";
 }
 
 class ConstructableFileSystemModifyEvent extends _ConstructableFileSystemEvent
     implements FileSystemModifyEvent {
+  @override
   final bool contentChanged;
+  @override
   final type = FileSystemEvent.modify;
 
   ConstructableFileSystemModifyEvent(
       String path, bool isDirectory, this.contentChanged)
       : super(path, isDirectory);
 
+  @override
   String toString() =>
       "FileSystemModifyEvent('$path', contentChanged=$contentChanged)";
 }
 
 class ConstructableFileSystemMoveEvent extends _ConstructableFileSystemEvent
     implements FileSystemMoveEvent {
+  @override
   final String destination;
+  @override
   final type = FileSystemEvent.move;
 
   ConstructableFileSystemMoveEvent(
       String path, bool isDirectory, this.destination)
       : super(path, isDirectory);
 
+  @override
   String toString() => "FileSystemMoveEvent('$path', '$destination')";
 }

lib/src/directory_watcher.dart

@@ -14,7 +14,7 @@ import 'directory_watcher/polling.dart';
 /// in the directory has changed.
 abstract class DirectoryWatcher implements Watcher {
   /// The directory whose contents are being monitored.
-  @Deprecated("Expires in 1.0.0. Use DirectoryWatcher.path instead.")
+  @Deprecated('Expires in 1.0.0. Use DirectoryWatcher.path instead.')
   String get directory;
 
   /// Creates a new [DirectoryWatcher] monitoring [directory].

lib/src/directory_watcher/linux.dart

@@ -25,6 +25,7 @@ import '../watch_event.dart';
 /// (issue 14424).
 class LinuxDirectoryWatcher extends ResubscribableWatcher
     implements DirectoryWatcher {
+  @override
   String get directory => path;
 
   LinuxDirectoryWatcher(String directory)
@@ -33,20 +34,25 @@ class LinuxDirectoryWatcher extends ResubscribableWatcher
 
 class _LinuxDirectoryWatcher
     implements DirectoryWatcher, ManuallyClosedWatcher {
+  @override
   String get directory => _files.root;
+  @override
   String get path => _files.root;
 
+  @override
   Stream<WatchEvent> get events => _eventsController.stream;
   final _eventsController = StreamController<WatchEvent>.broadcast();
 
+  @override
   bool get isReady => _readyCompleter.isCompleted;
 
+  @override
   Future get ready => _readyCompleter.future;
   final _readyCompleter = Completer();
 
   /// A stream group for the [Directory.watch] events of [path] and all its
   /// subdirectories.
-  var _nativeEvents = StreamGroup<FileSystemEvent>();
+  final _nativeEvents = StreamGroup<FileSystemEvent>();
 
   /// All known files recursively within [path].
   final PathSet _files;
@@ -60,7 +66,7 @@ class _LinuxDirectoryWatcher
   ///
   /// These are gathered together so that they may all be canceled when the
   /// watcher is closed.
-  final _subscriptions = Set<StreamSubscription>();
+  final _subscriptions = <StreamSubscription>{};
 
   _LinuxDirectoryWatcher(String path) : _files = PathSet(path) {
     _nativeEvents.add(Directory(path)
@@ -93,6 +99,7 @@ class _LinuxDirectoryWatcher
     }, cancelOnError: true);
   }
 
+  @override
   void close() {
     for (var subscription in _subscriptions) {
       subscription.cancel();
@@ -128,9 +135,9 @@ class _LinuxDirectoryWatcher
 
   /// The callback that's run when a batch of changes comes in.
   void _onBatch(List<FileSystemEvent> batch) {
-    var files = Set<String>();
-    var dirs = Set<String>();
-    var changed = Set<String>();
+    var files = <String>{};
+    var dirs = <String>{};
+    var changed = <String>{};
 
     // inotify event batches are ordered by occurrence, so we treat them as a
     // log of what happened to a file. We only emit events based on the
@@ -250,8 +257,8 @@ class _LinuxDirectoryWatcher
 
   /// Like [Stream.listen], but automatically adds the subscription to
   /// [_subscriptions] so that it can be canceled when [close] is called.
-  void _listen<T>(Stream<T> stream, void onData(T event),
-      {Function onError, void onDone(), bool cancelOnError}) {
+  void _listen<T>(Stream<T> stream, void Function(T) onData,
+      {Function onError, void Function() onDone, bool cancelOnError}) {
     StreamSubscription subscription;
     subscription = stream.listen(onData, onError: onError, onDone: () {
       _subscriptions.remove(subscription);

lib/src/directory_watcher/mac_os.dart

@@ -24,6 +24,7 @@ import '../watch_event.dart';
 /// [Directory.watch].
 class MacOSDirectoryWatcher extends ResubscribableWatcher
     implements DirectoryWatcher {
+  @override
   String get directory => path;
 
   MacOSDirectoryWatcher(String directory)
@@ -32,14 +33,19 @@ class MacOSDirectoryWatcher extends ResubscribableWatcher
 
 class _MacOSDirectoryWatcher
     implements DirectoryWatcher, ManuallyClosedWatcher {
+  @override
   String get directory => path;
+  @override
   final String path;
 
+  @override
   Stream<WatchEvent> get events => _eventsController.stream;
   final _eventsController = StreamController<WatchEvent>.broadcast();
 
+  @override
   bool get isReady => _readyCompleter.isCompleted;
 
+  @override
   Future get ready => _readyCompleter.future;
   final _readyCompleter = Completer();
 
@@ -64,7 +70,7 @@ class _MacOSDirectoryWatcher
 
   /// The subscriptions to [Directory.list] calls for listing the contents of a
   /// subdirectory that was moved into the watched directory.
-  final _listSubscriptions = Set<StreamSubscription<FileSystemEntity>>();
+  final _listSubscriptions = <StreamSubscription<FileSystemEntity>>{};
 
   /// The timer for tracking how long we wait for an initial batch of bogus
   /// events (see issue 14373).
@@ -85,6 +91,7 @@ class _MacOSDirectoryWatcher
         .then((_) => _readyCompleter.complete());
   }
 
+  @override
   void close() {
     if (_watchSubscription != null) _watchSubscription.cancel();
     if (_initialListSubscription != null) _initialListSubscription.cancel();
@@ -181,19 +188,19 @@ class _MacOSDirectoryWatcher
     // directory's full contents will be examined anyway, so we ignore such
     // events. Emitting them could cause useless or out-of-order events.
     var directories = unionAll(batch.map((event) {
-      if (!event.isDirectory) return Set<String>();
+      if (!event.isDirectory) return <String>{};
       if (event is FileSystemMoveEvent) {
-        return Set<String>.from([event.path, event.destination]);
+        return {event.path, event.destination};
       }
-      return Set<String>.from([event.path]);
+      return {event.path};
     }));
 
-    isInModifiedDirectory(String path) =>
+    bool isInModifiedDirectory(String path) =>
         directories.any((dir) => path != dir && path.startsWith(dir));
 
-    addEvent(String path, FileSystemEvent event) {
+    void addEvent(String path, FileSystemEvent event) {
       if (isInModifiedDirectory(path)) return;
-      eventsForPaths.putIfAbsent(path, () => Set<FileSystemEvent>()).add(event);
+      eventsForPaths.putIfAbsent(path, () => <FileSystemEvent>{}).add(event);
     }
 
     for (var event in batch) {