Use more async/await (#70)
* Use more async/await
- Change some bare `Future` into `Future<void>` to make sure we aren't
silently passing state where we don't expect.
- Change some methods with `.then` calls inside to `async`.
* Add another await
diff --git a/lib/src/async_queue.dart b/lib/src/async_queue.dart
index d864b1b..9f8bedf 100644
--- a/lib/src/async_queue.dart
+++ b/lib/src/async_queue.dart
@@ -5,7 +5,7 @@
import 'dart:async';
import 'dart:collection';
-typedef ItemProcessor<T> = Future Function(T item);
+typedef ItemProcessor<T> = Future<void> Function(T item);
/// A queue of items that are sequentially, asynchronously processed.
///
@@ -57,15 +57,14 @@
///
/// When complete, recursively calls itself to continue processing unless
/// the process was cancelled.
- Future _processNextItem() {
+ Future<void> _processNextItem() async {
var item = _items.removeFirst();
- return _processor(item).then((_) async {
- if (_items.isNotEmpty) return await _processNextItem();
+ await _processor(item);
+ if (_items.isNotEmpty) return _processNextItem();
- // We have drained the queue, stop processing and wait until something
- // has been enqueued.
- _isProcessing = false;
- return null;
- });
+ // We have drained the queue, stop processing and wait until something
+ // has been enqueued.
+ _isProcessing = false;
+ return null;
}
}
diff --git a/lib/src/directory_watcher/polling.dart b/lib/src/directory_watcher/polling.dart
index 735a807..f21a239 100644
--- a/lib/src/directory_watcher/polling.dart
+++ b/lib/src/directory_watcher/polling.dart
@@ -40,8 +40,8 @@
bool get isReady => _ready.isCompleted;
- Future get ready => _ready.future;
- final _ready = Completer();
+ Future<void> get ready => _ready.future;
+ final _ready = Completer<void>();
/// The amount of time the watcher pauses between successive polls of the
/// directory contents.
@@ -129,38 +129,41 @@
/// Processes [file] to determine if it has been modified since the last
/// time it was scanned.
- Future _processFile(String file) {
+ Future<void> _processFile(String file) async {
// `null` is the sentinel which means the directory listing is complete.
- if (file == null) return _completePoll();
+ if (file == null) {
+ await _completePoll();
+ return;
+ }
- return getModificationTime(file).then((modified) {
- if (_events.isClosed) return null;
+ final modified = await modificationTime(file);
- var lastModified = _lastModifieds[file];
+ if (_events.isClosed) return;
- // If its modification time hasn't changed, assume the file is unchanged.
- if (lastModified != null && lastModified == modified) {
- // The file is still here.
- _polledFiles.add(file);
- return null;
- }
+ var lastModified = _lastModifieds[file];
- if (_events.isClosed) return null;
-
- _lastModifieds[file] = modified;
+ // If its modification time hasn't changed, assume the file is unchanged.
+ if (lastModified != null && lastModified == modified) {
+ // The file is still here.
_polledFiles.add(file);
+ return;
+ }
- // Only notify if we're ready to emit events.
- if (!isReady) return null;
+ if (_events.isClosed) return;
- var type = lastModified == null ? ChangeType.ADD : ChangeType.MODIFY;
- _events.add(WatchEvent(type, file));
- });
+ _lastModifieds[file] = modified;
+ _polledFiles.add(file);
+
+ // Only notify if we're ready to emit events.
+ if (!isReady) return;
+
+ var type = lastModified == null ? ChangeType.ADD : ChangeType.MODIFY;
+ _events.add(WatchEvent(type, file));
}
/// After the directory listing is complete, this determines which files were
/// removed and then restarts the next poll.
- Future _completePoll() {
+ Future<void> _completePoll() async {
// Any files that were not seen in the last poll but that we have a
// status for must have been removed.
var removedFiles = _lastModifieds.keys.toSet().difference(_polledFiles);
@@ -172,9 +175,8 @@
if (!isReady) _ready.complete();
// Wait and then poll again.
- return Future.delayed(_pollingDelay).then((_) {
- if (_events.isClosed) return;
- _poll();
- });
+ await Future.delayed(_pollingDelay);
+ if (_events.isClosed) return;
+ _poll();
}
}
diff --git a/lib/src/directory_watcher/windows.dart b/lib/src/directory_watcher/windows.dart
index 7294c17..85fef5f 100644
--- a/lib/src/directory_watcher/windows.dart
+++ b/lib/src/directory_watcher/windows.dart
@@ -52,7 +52,7 @@
bool get isReady => _readyCompleter.isCompleted;
- Future get ready => _readyCompleter.future;
+ Future<void> get ready => _readyCompleter.future;
final _readyCompleter = Completer();
final Map<String, _EventBatcher> _eventBatchers =
@@ -380,7 +380,7 @@
/// Starts or restarts listing the watched directory to get an initial picture
/// of its state.
- Future _listDir() {
+ Future<void> _listDir() {
assert(!isReady);
if (_initialListSubscription != null) _initialListSubscription.cancel();
diff --git a/lib/src/file_watcher/polling.dart b/lib/src/file_watcher/polling.dart
index a0466b5..e2bf5dd 100644
--- a/lib/src/file_watcher/polling.dart
+++ b/lib/src/file_watcher/polling.dart
@@ -62,7 +62,7 @@
DateTime modified;
try {
- modified = await getModificationTime(path);
+ modified = await modificationTime(path);
} on FileSystemException catch (error, stackTrace) {
if (!_eventsController.isClosed) {
_eventsController.addError(error, stackTrace);
diff --git a/lib/src/resubscribable.dart b/lib/src/resubscribable.dart
index e00ebb0..8de3dfb 100644
--- a/lib/src/resubscribable.dart
+++ b/lib/src/resubscribable.dart
@@ -31,8 +31,8 @@
bool get isReady => _readyCompleter.isCompleted;
- Future get ready => _readyCompleter.future;
- var _readyCompleter = Completer();
+ Future<void> get ready => _readyCompleter.future;
+ var _readyCompleter = Completer<void>();
/// Creates a new [ResubscribableWatcher] wrapping the watchers
/// emitted by [_factory].
@@ -41,16 +41,17 @@
StreamSubscription subscription;
_eventsController = StreamController<WatchEvent>.broadcast(
- onListen: () {
+ onListen: () async {
watcher = _factory();
subscription = watcher.events.listen(_eventsController.add,
onError: _eventsController.addError,
onDone: _eventsController.close);
- // It's important that we complete the value of [_readyCompleter] at the
- // time [onListen] is called, as opposed to the value when [watcher.ready]
- // fires. A new completer may be created by that time.
- watcher.ready.then(_readyCompleter.complete);
+ // It's important that we complete the value of [_readyCompleter] at
+ // the time [onListen] is called, as opposed to the value when
+ // [watcher.ready] fires. A new completer may be created by that time.
+ await watcher.ready;
+ _readyCompleter.complete();
},
onCancel: () {
// Cancel the subscription before closing the watcher so that the
diff --git a/lib/src/stat.dart b/lib/src/stat.dart
index a569208..6430d0b 100644
--- a/lib/src/stat.dart
+++ b/lib/src/stat.dart
@@ -22,10 +22,11 @@
}
/// Gets the modification time for the file at [path].
-Future<DateTime> getModificationTime(String path) {
+Future<DateTime> modificationTime(String path) async {
if (_mockTimeCallback != null) {
- return Future.value(_mockTimeCallback(path));
+ return _mockTimeCallback(path);
}
- return FileStat.stat(path).then((stat) => stat.modified);
+ final stat = await FileStat.stat(path);
+ return stat.modified;
}
diff --git a/test/utils.dart b/test/utils.dart
index 57b4563..2e0ad01 100644
--- a/test/utils.dart
+++ b/test/utils.dart
@@ -79,8 +79,9 @@
/// at the end of a test. Otherwise, if they don't occur, the test will wait
/// indefinitely because they might in the future and because the watcher is
/// normally only closed after the test completes.
-void startClosingEventStream() {
- pumpEventQueue().then((_) => _watcherEvents.cancel(immediate: true));
+void startClosingEventStream() async {
+ await pumpEventQueue();
+ await _watcherEvents.cancel(immediate: true);
}
/// A list of [StreamMatcher]s that have been collected using
