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1 // Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file | |
2 // for details. All rights reserved. Use of this source code is governed by a | |
3 // BSD-style license that can be found in the LICENSE file. | |
4 | |
5 library async.closed_stream_sink; | |
6 | |
7 import 'dart:async'; | |
8 | |
9 /// A [StreamSink] that's created in a closed state. | |
10 /// | |
11 /// The sink silently drops events until [close] is called, at which point it | |
12 /// throws [StateError]s when events are added. | |
Lasse Reichstein Nielsen
2016/01/22 09:13:46
It confuses me that it's "in a closed state" befor
nweiz
2016/01/25 22:39:24
Done.
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13 /// | |
14 /// This can be used when a sink is needed but no events are actually intended | |
15 /// to be added. The [new ClosedStreamSink.error] constructor can be used to | |
Lasse Reichstein Nielsen
2016/01/22 09:13:46
If it's not intended to receive events, why not th
nweiz
2016/01/25 22:39:24
It's meant to be used to mimic the remote stream b
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16 /// represent errors in creating a sink. | |
Lasse Reichstein Nielsen
2016/01/22 09:13:46
How does errors in a done future represent errors
nweiz
2016/01/25 22:39:24
From the StreamSink documentation: "If the StreamS
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17 class ClosedStreamSink<T> implements StreamSink<T> { | |
18 final Future done; | |
19 | |
20 /// Whether the sink has been closed. | |
21 /// | |
22 /// To be consistent with other stream sinks that have been closed remotely, | |
Lasse Reichstein Nielsen
2016/01/22 09:13:46
I would use the name "canceled" for what the recei
nweiz
2016/01/25 22:39:24
I think changing the name and updating the class d
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23 /// this ignores events until [close] is called. After that, it throws | |
24 /// [StateError]s. | |
25 var _closed = false; | |
26 | |
27 /// Creates a closed sink. | |
28 /// | |
29 /// If [done] is passed, it's used as the [Sink.done] future. Otherwise, a | |
30 /// completed future is used. | |
31 ClosedStreamSink({Future done}) : done = done ?? new Future.value(); | |
32 | |
33 /// Creates a closed sink whose [done] future emits [error]. | |
34 ClosedStreamSink.error(error, [StackTrace stackTrace]) | |
35 : done = new Future.error(error, stackTrace); | |
Lasse Reichstein Nielsen
2016/01/22 09:13:46
This will cause the error to be uncaught in the ne
nweiz
2016/01/25 22:39:24
Done.
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36 | |
37 void add(T data) { | |
38 if (!_closed) return; | |
39 throw new StateError("Cannot add to a closed sink."); | |
Lasse Reichstein Nielsen
2016/01/22 09:13:46
How about just:
if (_closed) throw ...;
The curr
nweiz
2016/01/25 22:39:24
Done.
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40 } | |
41 | |
42 void addError(error, [StackTrace stackTrace]) { | |
43 if (!_closed) return; | |
44 throw new StateError("Cannot add to a closed sink."); | |
45 } | |
46 | |
47 Future addStream(Stream<T> stream) { | |
48 if (_closed) { | |
49 throw new StateError("Cannot add to a closed sink."); | |
50 } | |
51 | |
Lasse Reichstein Nielsen
2016/01/22 09:13:46
You need a bit here to remember that you are addin
nweiz
2016/01/25 22:39:24
Done.
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52 return stream.listen(null).cancel() ?? new Future.value(); | |
Lasse Reichstein Nielsen
2016/01/22 09:13:46
In dart:async we have a Future<dynamic> completed
nweiz
2016/01/25 22:39:24
I don't think it's worth the complexity.
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53 } | |
54 | |
55 Future close() { | |
56 _closed = true; | |
57 return done; | |
58 } | |
59 } | |
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