Fix subscription handling in stream decoder

Fix subscription handling in stream decoder

The _StringDecoder did not handle unsubscribe correctly (the added
test did not terminate as the unsubscribe did not cause stdin to be
closed)

Fixed by extending StreamEventTransformer which has all the
logic. Changed a number of other transformers to use
StreamEventTransformer as well.

Fixed a bug in the StreamEventTransformer implementation.

R=floitsch@google.com

BUG=

Committed: https://code.google.com/p/dart/source/detail?r=19046

[floitsch, 2013-02-26 14:47:25]

LGTM.

Consider switching to map, as in https://codereview.chromium.org/12335093

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/async/stream.dart
File sdk/lib/async/stream.dart (right):

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/async/stream.dart#...
sdk/lib/async/stream.dart:1019: true == unsubscribeOnError);
I prefer identical(unsubscribeOnError, true) to switching the order of the
operands. It shows the intent.

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/io/string_transfor...
File sdk/lib/io/string_transformer.dart (right):

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/io/string_transfor...
sdk/lib/io/string_transformer.dart:163: void handle(String data,
StreamSink<String> sink, bool isClosing) {
make it private.

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/io/string_transfor...
sdk/lib/io/string_transformer.dart:210: handle("", sink, true);
sink.close()

[Søren Gjesse, 2013-02-26 15:23:32]

Kept all classes extending StreamEventTransformer for consistency. From the
tests I did it also does try...catch as I could just throw in handleData.

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/async/stream.dart
File sdk/lib/async/stream.dart (right):

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/async/stream.dart#...
sdk/lib/async/stream.dart:1019: true == unsubscribeOnError);
On 2013/02/26 14:47:26, floitsch wrote:
> I prefer identical(unsubscribeOnError, true) to switching the order of the
> operands. It shows the intent.

Done.

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/io/string_transfor...
File sdk/lib/io/string_transformer.dart (right):

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/io/string_transfor...
sdk/lib/io/string_transformer.dart:163: void handle(String data,
StreamSink<String> sink, bool isClosing) {
On 2013/02/26 14:47:26, floitsch wrote:
> make it private.

Done.

https://codereview.chromium.org/12313127/diff/2001/sdk/lib/io/string_transfor...
sdk/lib/io/string_transformer.dart:210: handle("", sink, true);
On 2013/02/26 14:47:26, floitsch wrote:
> sink.close()

Thanks.

[Søren Gjesse, 2013-02-26 15:24:33]

Committed patchset #3 manually as r19046 (presubmit successful).