Revert "Make Stream.where, etc., be documented as inheriting broadcast state."

sdk/lib/async/stream.dart

Index: sdk/lib/async/stream.dart
diff --git a/sdk/lib/async/stream.dart b/sdk/lib/async/stream.dart
index a55d7c8cf4bfa104774903b623e7adf27536bcba..a3b266f4f3b37b990dd777fe8fa1a4233bcd9e49 100644
--- a/sdk/lib/async/stream.dart
+++ b/sdk/lib/async/stream.dart
@@ -49,11 +49,8 @@ part of dart.async;
  *
  * Broadcast streams are used for independent events/observers.
  *
- * Stream transformations, such as [where] and [skip],
- * return the same type of stream as the one the method was called on,
- * unless otherwise noted.
- *
- * If several listeners want to listen to the returned
+ * Stream transformations, such as [where] and [skip], always return
+ * non-broadcast streams. If several listeners want to listen to the returned
  * stream, use [asBroadcastStream] to create a broadcast stream on top of the
  * non-broadcast stream.
  *
@@ -265,7 +262,7 @@ abstract class Stream<T> {
    * The new stream sends the same error and done events as this stream,
    * but it only sends the data events that satisfy the [test].
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream<T> where(bool test(T event)) {
     return new _WhereStream<T>(this, test);
@@ -275,7 +272,7 @@ abstract class Stream<T> {
    * Creates a new stream that converts each element of this stream
    * to a new value using the [convert] function.
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream map(convert(T event)) {
     return new _MapStream<T, dynamic>(this, convert);
@@ -288,8 +285,6 @@ abstract class Stream<T> {
    * This acts like [map], except that [convert] may return a [Future],
    * and in that case, the stream waits for that future to complete before
    * continuing with its result.
-   *
-   * The returned stream is not a broadcast stream.
    */
   Stream asyncMap(convert(T event)) {
     StreamController controller;
@@ -337,8 +332,6 @@ abstract class Stream<T> {
    *
    * If [convert] returns `null`, no value is put on the output stream,
    * just as if it returned an empty stream.
-   *
-   * The returned stream is a not a broadcast stream.
    */
   Stream asyncExpand(Stream convert(T event)) {
     StreamController controller;
@@ -395,7 +388,7 @@ abstract class Stream<T> {
    * [Stream.transform] to handle the event by writing a data event to
    * the output sink
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream<T> handleError(Function onError, { bool test(error) }) {
     return new _HandleErrorStream<T>(this, onError, test);
@@ -409,7 +402,7 @@ abstract class Stream<T> {
    * and each of these new events are then sent by the returned stream
    * in order.
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream expand(Iterable convert(T value)) {
     return new _ExpandStream<T, dynamic>(this, convert);
@@ -426,9 +419,6 @@ abstract class Stream<T> {
    * Chains this stream as the input of the provided [StreamTransformer].
    *
    * Returns the result of [:streamTransformer.bind:] itself.
-   *
-   * The `streamTransformer` can decide whether it wants to return a
-   * broadcast stream or not.
    */
   Stream transform(StreamTransformer<T, dynamic> streamTransformer) {
     return streamTransformer.bind(this);
@@ -748,7 +738,7 @@ abstract class Stream<T> {
    * means that single-subscription (non-broadcast) streams are closed and
    * cannot be reused after a call to this method.
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream<T> take(int count) {
     return new _TakeStream(this, count);
@@ -768,7 +758,7 @@ abstract class Stream<T> {
    * means that single-subscription (non-broadcast) streams are closed and
    * cannot be reused after a call to this method.
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream<T> takeWhile(bool test(T element)) {
     return new _TakeWhileStream(this, test);
@@ -777,7 +767,7 @@ abstract class Stream<T> {
   /**
    * Skips the first [count] data events from this stream.
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream<T> skip(int count) {
     return new _SkipStream(this, count);
@@ -791,7 +781,7 @@ abstract class Stream<T> {
    * Starting with the first data event where [test] returns false for the
    * event data, the returned stream will have the same events as this stream.
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream<T> skipWhile(bool test(T element)) {
     return new _SkipWhileStream(this, test);
@@ -806,7 +796,7 @@ abstract class Stream<T> {
    * Equality is determined by the provided [equals] method. If that is
    * omitted, the '==' operator on the last provided data element is used.
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream<T> distinct([bool equals(T previous, T next)]) {
     return new _DistinctStream(this, equals);
@@ -1098,12 +1088,12 @@ abstract class Stream<T> {
    * If `onTimeout` is omitted, a timeout will just put a [TimeoutException]
    * into the error channel of the returned stream.
    *
-   * The returned stream is a broadcast stream if this stream is.
+   * The returned stream is not a broadcast stream, even if this stream is.
    */
   Stream timeout(Duration timeLimit, {void onTimeout(EventSink sink)}) {
-    StreamController controller;
-    // The following variables are set on listen.
     StreamSubscription<T> subscription;
+    _StreamController controller;
+    // The following variables are set on listen.
     Timer timer;
     Zone zone;
     Function timeout;
@@ -1122,51 +1112,46 @@ abstract class Stream<T> {
       timer.cancel();
       controller.close();
     }
-    void onListen() {
-      // This is the onListen callback for of controller.
-      // It runs in the same zone that the subscription was created in.
-      // Use that zone for creating timers and running the onTimeout
-      // callback.
-      zone = Zone.current;
-      if (onTimeout == null) {
-        timeout = () {
-          controller.addError(new TimeoutException("No stream event",
-                                                   timeLimit));
-        };
-      } else {
-        onTimeout = zone.registerUnaryCallback(onTimeout);
-        _ControllerEventSinkWrapper wrapper =
-            new _ControllerEventSinkWrapper(null);
-        timeout = () {
-          wrapper._sink = controller;  // Only valid during call.
-          zone.runUnaryGuarded(onTimeout, wrapper);
-          wrapper._sink = null;
-        };
-      }
-
-      subscription = this.listen(onData, onError: onError, onDone: onDone);
-      timer = zone.createTimer(timeLimit, timeout);
-    }
-    Future onCancel() {
-      timer.cancel();
-      Future result = subscription.cancel();
-      subscription = null;
-      return result;
-    }
-    controller = isBroadcast
-        ? new _SyncBroadcastStreamController(onListen, onCancel)
-        : new _SyncStreamController(
-              onListen,
-              () {
-                // Don't null the timer, onCancel may call cancel again.
-                timer.cancel();
-                subscription.pause();
-              },
-              () {
-                subscription.resume();
-                timer = zone.createTimer(timeLimit, timeout);
-              },
-              onCancel);
+    controller = new _SyncStreamController(
+        () {
+          // This is the onListen callback for of controller.
+          // It runs in the same zone that the subscription was created in.
+          // Use that zone for creating timers and running the onTimeout
+          // callback.
+          zone = Zone.current;
+          if (onTimeout == null) {
+            timeout = () {
+              controller.addError(new TimeoutException("No stream event",
+                                                       timeLimit));
+            };
+          } else {
+            onTimeout = zone.registerUnaryCallback(onTimeout);
+            _ControllerEventSinkWrapper wrapper =
+                new _ControllerEventSinkWrapper(null);
+            timeout = () {
+              wrapper._sink = controller;  // Only valid during call.
+              zone.runUnaryGuarded(onTimeout, wrapper);
+              wrapper._sink = null;
+            };
+          }
+
+          subscription = this.listen(onData, onError: onError, onDone: onDone);
+          timer = zone.createTimer(timeLimit, timeout);
+        },
+        () {
+          timer.cancel();
+          subscription.pause();
+        },
+        () {
+          subscription.resume();
+          timer = zone.createTimer(timeLimit, timeout);
+        },
+        () {
+          timer.cancel();
+          Future result = subscription.cancel();
+          subscription = null;
+          return result;
+        });
     return controller.stream;
   }
 }