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| 1 // Copyright (c) 2014, 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 /// Functions go in this file as opposed to lib/src/utils.dart if they need to | |
| 6 /// be accessible to the transformer-loading isolate. | |
| 7 library pub.asset.utils; | |
| 8 | |
| 9 import 'dart:async'; | |
| 10 | |
| 11 /// A regular expression to match the exception prefix that some exceptions' | |
| 12 /// [Object.toString] values contain. | |
| 13 final _exceptionPrefix = new RegExp(r'^([A-Z][a-zA-Z]*)?(Exception|Error): '); | |
| 14 | |
| 15 /// Get a string description of an exception. | |
| 16 /// | |
| 17 /// Many exceptions include the exception class name at the beginning of their | |
| 18 /// [toString], so we remove that if it exists. | |
| 19 String getErrorMessage(error) => | |
| 20 error.toString().replaceFirst(_exceptionPrefix, ''); | |
| 21 | |
| 22 /// Returns a buffered stream that will emit the same values as the stream | |
| 23 /// returned by [future] once [future] completes. | |
| 24 /// | |
| 25 /// If [future] completes to an error, the return value will emit that error and | |
| 26 /// then close. | |
| 27 /// | |
| 28 /// If [broadcast] is true, a broadcast stream is returned. This assumes that | |
| 29 /// the stream returned by [future] will be a broadcast stream as well. | |
| 30 /// [broadcast] defaults to false. | |
| 31 Stream futureStream(Future<Stream> future, {bool broadcast: false}) { | |
| 32 var subscription; | |
| 33 var controller; | |
| 34 | |
| 35 future = future.catchError((e, stackTrace) { | |
| 36 // Since [controller] is synchronous, it's likely that emitting an error | |
| 37 // will cause it to be cancelled before we call close. | |
| 38 if (controller != null) controller.addError(e, stackTrace); | |
| 39 if (controller != null) controller.close(); | |
| 40 controller = null; | |
| 41 }); | |
| 42 | |
| 43 onListen() { | |
| 44 future.then((stream) { | |
| 45 if (controller == null) return; | |
| 46 subscription = stream.listen( | |
| 47 controller.add, | |
| 48 onError: controller.addError, | |
| 49 onDone: controller.close); | |
| 50 }); | |
| 51 } | |
| 52 | |
| 53 onCancel() { | |
| 54 if (subscription != null) subscription.cancel(); | |
| 55 subscription = null; | |
| 56 controller = null; | |
| 57 } | |
| 58 | |
| 59 if (broadcast) { | |
| 60 controller = new StreamController.broadcast( | |
| 61 sync: true, onListen: onListen, onCancel: onCancel); | |
| 62 } else { | |
| 63 controller = new StreamController( | |
| 64 sync: true, onListen: onListen, onCancel: onCancel); | |
| 65 } | |
| 66 return controller.stream; | |
| 67 } | |
| 68 | |
| 69 /// Returns a [Stream] that will emit the same values as the stream returned by | |
| 70 /// [callback]. | |
| 71 /// | |
| 72 /// [callback] will only be called when the returned [Stream] gets a subscriber. | |
| 73 Stream callbackStream(Stream callback()) { | |
| 74 var subscription; | |
| 75 var controller; | |
| 76 controller = new StreamController(onListen: () { | |
| 77 subscription = callback().listen(controller.add, | |
| 78 onError: controller.addError, | |
| 79 onDone: controller.close); | |
| 80 }, | |
| 81 onCancel: () => subscription.cancel(), | |
| 82 onPause: () => subscription.pause(), | |
| 83 onResume: () => subscription.resume(), | |
| 84 sync: true); | |
| 85 return controller.stream; | |
| 86 } | |
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Chromium Code Reviews
Issue 896623005:
Use native async/await support in pub. (Closed)
Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart