Index: mojo/public/dart/third_party/glob/lib/src/stream_pool.dart |
diff --git a/mojo/public/dart/third_party/glob/lib/src/stream_pool.dart b/mojo/public/dart/third_party/glob/lib/src/stream_pool.dart |
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index 0000000000000000000000000000000000000000..641751333426d903d2f021515bd30a5fb6034225 |
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+++ b/mojo/public/dart/third_party/glob/lib/src/stream_pool.dart |
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+// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
+// for details. All rights reserved. Use of this source code is governed by a |
+// BSD-style license that can be found in the LICENSE file. |
+ |
+library glob.stream_pool; |
+ |
+import 'dart:async'; |
+ |
+/// A pool of streams whose events are unified and emitted through a central |
+/// stream. |
+class StreamPool<T> { |
+ /// The stream through which all events from streams in the pool are emitted. |
+ Stream<T> get stream => _controller.stream; |
+ final StreamController<T> _controller; |
+ |
+ /// Subscriptions to the streams that make up the pool. |
+ final _subscriptions = new Map<Stream<T>, StreamSubscription<T>>(); |
+ |
+ /// Whether this pool should be closed when it becomes empty. |
+ bool _closeWhenEmpty = false; |
+ |
+ /// Creates a new stream pool that only supports a single subscriber. |
+ /// |
+ /// Any events from broadcast streams in the pool will be buffered until a |
+ /// listener is subscribed. |
+ StreamPool() |
+ // Create the controller as sync so that any sync input streams will be |
+ // forwarded synchronously. Async input streams will have their asynchrony |
+ // preserved, since _controller.add will be called asynchronously. |
+ : _controller = new StreamController<T>(sync: true); |
+ |
+ /// Creates a new stream pool where [stream] can be listened to more than |
+ /// once. |
+ /// |
+ /// Any events from buffered streams in the pool will be emitted immediately, |
+ /// regardless of whether [stream] has any subscribers. |
+ StreamPool.broadcast() |
+ // Create the controller as sync so that any sync input streams will be |
+ // forwarded synchronously. Async input streams will have their asynchrony |
+ // preserved, since _controller.add will be called asynchronously. |
+ : _controller = new StreamController<T>.broadcast(sync: true); |
+ |
+ /// Adds [stream] as a member of this pool. |
+ /// |
+ /// Any events from [stream] will be emitted through [this.stream]. If |
+ /// [stream] is sync, they'll be emitted synchronously; if [stream] is async, |
+ /// they'll be emitted asynchronously. |
+ void add(Stream<T> stream) { |
+ if (_subscriptions.containsKey(stream)) return; |
+ _subscriptions[stream] = stream.listen(_controller.add, |
+ onError: _controller.addError, |
+ onDone: () => remove(stream)); |
+ } |
+ |
+ /// Removes [stream] as a member of this pool. |
+ void remove(Stream<T> stream) { |
+ var subscription = _subscriptions.remove(stream); |
+ if (subscription != null) subscription.cancel(); |
+ if (_closeWhenEmpty && _subscriptions.isEmpty) close(); |
+ } |
+ |
+ /// Removes all streams from this pool and closes [stream]. |
+ void close() { |
+ for (var subscription in _subscriptions.values) { |
+ subscription.cancel(); |
+ } |
+ _subscriptions.clear(); |
+ _controller.close(); |
+ } |
+ |
+ /// The next time this pool becomes empty, close it. |
+ void closeWhenEmpty() { |
+ if (_subscriptions.isEmpty) close(); |
+ _closeWhenEmpty = true; |
+ } |
+} |