Index: lib/src/stream_sink_transformer/stream_transformer_wrapper.dart |
diff --git a/lib/src/stream_sink_transformer/stream_transformer_wrapper.dart b/lib/src/stream_sink_transformer/stream_transformer_wrapper.dart |
new file mode 100644 |
index 0000000000000000000000000000000000000000..b53f20865c92edf5fd6ec50702faa1dd31311dc6 |
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+++ b/lib/src/stream_sink_transformer/stream_transformer_wrapper.dart |
@@ -0,0 +1,62 @@ |
+// Copyright (c) 2016, 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 async.stream_sink_transformer.stream_transformer_wrapper; |
+ |
+import 'dart:async'; |
+ |
+import '../stream_sink_transformer.dart'; |
+ |
+/// A [StreamSinkTransformer] that wraps a pre-existing [StreamTransformer]. |
+class StreamTransformerWrapper<S, T> implements StreamSinkTransformer<S, T> { |
+ /// The wrapped transformer. |
+ final StreamTransformer<S, T> _transformer; |
+ |
+ const StreamTransformerWrapper(this._transformer); |
+ |
+ StreamSink<S> bind(StreamSink<T> sink) => |
+ new _StreamTransformerWrapperSink<S, T>(_transformer, sink); |
+} |
+ |
+/// A sink created by [StreamTransformerWrapper]. |
+class _StreamTransformerWrapperSink<S, T> implements StreamSink<S> { |
+ /// The controller through which events are passed. |
+ /// |
+ /// This is used to create a stream that can be transformed by the wrapped |
+ /// transformer. |
+ final _controller = new StreamController<S>(sync: true); |
+ |
+ /// The original sink that's being transformed. |
+ final StreamSink<T> _inner; |
+ |
+ Future get done => _inner.done; |
+ |
+ _StreamTransformerWrapperSink(StreamTransformer<S, T> transformer, |
+ this._inner) { |
+ _controller.stream.transform(transformer).listen( |
+ _inner.add, |
+ onError: _inner.addError, |
+ onDone: () { |
+ // Ignore any errors that come from this call to [_inner.close]. The |
+ // user can access them through [done] or the value returned from |
+ // [this.close], and we don't want them to get top-leveled. |
+ _inner.close().catchError((_) {}); |
+ }); |
+ } |
+ |
+ void add(S event) { |
+ _controller.add(event); |
+ } |
+ |
+ void addError(error, [StackTrace stackTrace]) { |
+ _controller.addError(error, stackTrace); |
+ } |
+ |
+ Future addStream(Stream<S> stream) => _controller.addStream(stream); |
+ |
+ Future close() { |
+ _controller.close(); |
+ return _inner.done; |
+ } |
+} |