Remove transformEvents and make StreamEventTransformer extend StreamTransformer.

Remove transformEvents and make StreamEventTransformer extend StreamTransformer.

Make a StreamEventTransformer the default for the StreamTransformer
factory constructor, and remove the old implementation.

Committed: https://code.google.com/p/dart/source/detail?r=17761

[floitsch, 2013-01-29 13:37:04]

LGTM.

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream.dart
File sdk/lib/async/stream.dart (right):

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream.dart#new...
sdk/lib/async/stream.dart:933: *     someTypeStream.transform(new
StreamTransformer<Type, Type>(
Make it a real example.
stringStream.transform(new StreamTransformer<String, String>(
    handleData: (String value, StreamSink<String> sink) {
      sink.add(value);
      sink.add(value);  // Double the incoming events.
    }));

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream.dart#new...
sdk/lib/async/stream.dart:962: * types of events for each incoming event. Pauses
on the returned
The pause needs more description:
- does the StreamEventTransformer buffer if necessary?
- I guess that your sentence means that pauses are forwarded to the stream's
input-stream.

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream_pipe.dart
File sdk/lib/async/stream_pipe.dart (left):

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream_pipe.dar...
sdk/lib/async/stream_pipe.dart:576: try {
Do we really need to remove the try?
I would expect throwing handlers to behave similar to where/mappedBy.
new StreamTransformer(handleData: (data, sink) {
  throw "foo";
})
should thus be in the error-stream.

Or is this caught somewhere else?

https://codereview.chromium.org/12082047/diff/1/tests/lib/async/stream_contro...
File tests/lib/async/stream_controller_test.dart (right):

https://codereview.chromium.org/12082047/diff/1/tests/lib/async/stream_contro...
tests/lib/async/stream_controller_test.dart:98: handleError: (e, s) {
s.add(e.error); },
The e.error is not necessary anymore. Is it?

[Lasse Reichstein Nielsen, 2013-01-29 14:04:14]

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream.dart
File sdk/lib/async/stream.dart (right):

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream.dart#new...
sdk/lib/async/stream.dart:933: *     someTypeStream.transform(new
StreamTransformer<Type, Type>(
On 2013/01/29 13:37:04, floitsch wrote:
> Make it a real example.
> stringStream.transform(new StreamTransformer<String, String>(
>     handleData: (String value, StreamSink<String> sink) {
>       sink.add(value);
>       sink.add(value);  // Double the incoming events.
>     }));

Done.

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream.dart#new...
sdk/lib/async/stream.dart:962: * types of events for each incoming event. Pauses
on the returned
The latter. The returned stream can't buffer at all, it can just wrap a
subscription in another and transform events on the way. All pauses and
unsubscribes are forwarded.
Reworded slightly.

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream_pipe.dart
File sdk/lib/async/stream_pipe.dart (left):

https://codereview.chromium.org/12082047/diff/1/sdk/lib/async/stream_pipe.dar...
sdk/lib/async/stream_pipe.dart:576: try {
We don't need to remove them. Let's keep them for consistency.
It's different from what the methods on StreamEventTransformer do - if they
throw it will sent to the global event handler.
The same happens here.
I'll add try/catch around the call in the wrapping subscription, so both are
handled.

https://codereview.chromium.org/12082047/diff/1/tests/lib/async/stream_contro...
File tests/lib/async/stream_controller_test.dart (right):

https://codereview.chromium.org/12082047/diff/1/tests/lib/async/stream_contro...
tests/lib/async/stream_controller_test.dart:98: handleError: (e, s) {
s.add(e.error); },
In this case, I convert the thrown value to a data event, so this is what I
want. I don't want the AsyncError as the data event.