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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 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. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 /// Generic utility functions. Stuff that should possibly be in core. | 5 /// Generic utility functions. Stuff that should possibly be in core. |
6 library utils; | 6 library utils; |
7 | 7 |
8 import 'dart:async'; | 8 import 'dart:async'; |
9 import 'dart:crypto'; | 9 import 'dart:crypto'; |
10 import 'dart:isolate'; | 10 import 'dart:isolate'; |
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111 return completer.future; | 111 return completer.future; |
112 } | 112 } |
113 | 113 |
114 /// Configures [future] so that its result (success or exception) is passed on | 114 /// Configures [future] so that its result (success or exception) is passed on |
115 /// to [completer]. | 115 /// to [completer]. |
116 void chainToCompleter(Future future, Completer completer) { | 116 void chainToCompleter(Future future, Completer completer) { |
117 future.then((value) => completer.complete(value), | 117 future.then((value) => completer.complete(value), |
118 onError: (e) => completer.completeError(e.error, e.stackTrace)); | 118 onError: (e) => completer.completeError(e.error, e.stackTrace)); |
119 } | 119 } |
120 | 120 |
121 // TODO(nweiz): remove this when issue 7964 is fixed. | |
122 /// Returns a [Future] that will complete to the first element of [stream]. | |
123 /// Unlike [Stream.first], this is safe to use with single-subscription streams. | |
124 Future streamFirst(Stream stream) { | |
125 var completer = new Completer(); | |
126 var subscription; | |
127 subscription = stream.listen((value) { | |
128 subscription.cancel(); | |
129 completer.complete(value); | |
130 }, | |
131 onError: (e) => completer.completeError(e.error, e.stackTrace), | |
132 onDone: () => completer.completeError(new StateError("No elements")), | |
133 unsubscribeOnError: true); | |
134 return completer.future; | |
135 } | |
136 | |
137 /// Returns a wrapped version of [stream] along with a [StreamSubscription] that | |
138 /// can be used to control the wrapped stream. | |
139 Pair<Stream, StreamSubscription> streamWithSubscription(Stream stream) { | |
140 var controller = stream.isSingleSubscription ? | |
141 new StreamController() : | |
142 new StreamController.multiSubscription(); | |
143 var subscription = stream.listen(controller.add, | |
144 onError: controller.signalError, | |
145 onDone: controller.close); | |
146 return new Pair<Stream, StreamSubscription>(controller.stream, subscription); | |
147 } | |
148 | |
149 // TODO(nweiz): remove this when issue 7787 is fixed. | |
150 /// Creates two single-subscription [Stream]s that each emit all values and | |
151 /// errors from [stream]. This is useful if [stream] is single-subscription but | |
152 /// multiple subscribers are necessary. | |
153 Pair<Stream, Stream> tee(Stream stream) { | |
154 var controller1 = new StreamController(); | |
155 var controller2 = new StreamController(); | |
156 stream.listen((value) { | |
157 controller1.add(value); | |
158 controller2.add(value); | |
159 }, onError: (error) { | |
160 controller1.signalError(error); | |
161 controller2.signalError(error); | |
162 }, onDone: () { | |
163 controller1.close(); | |
164 controller2.close(); | |
165 }); | |
166 return new Pair<Stream, Stream>(controller1.stream, controller2.stream); | |
167 } | |
168 | |
169 /// A regular expression matching a line termination character or character | |
170 /// sequence. | |
171 final RegExp _lineRegexp = new RegExp(r"\r\n|\r|\n"); | |
172 | |
173 /// Converts a stream of arbitrarily chunked strings into a line-by-line stream. | |
174 /// The lines don't include line termination characters. A single trailing | |
175 /// newline is ignored. | |
176 Stream<String> streamToLines(Stream<String> stream) { | |
177 var buffer = new StringBuffer(); | |
178 return stream.transform(new StreamTransformer.from( | |
179 onData: (chunk, sink) { | |
180 var lines = chunk.split(_lineRegexp); | |
181 var leftover = lines.removeLast(); | |
182 for (var line in lines) { | |
183 if (!buffer.isEmpty) { | |
184 buffer.add(line); | |
185 line = buffer.toString(); | |
186 buffer.clear(); | |
187 } | |
188 | |
189 sink.add(line); | |
190 } | |
191 buffer.add(leftover); | |
192 }, onDone: (sink) { | |
193 if (!buffer.isEmpty) sink.add(buffer.toString()); | |
194 sink.close(); | |
195 })); | |
196 } | |
197 | |
198 // TODO(nweiz): unify the following functions with the utility functions in | 121 // TODO(nweiz): unify the following functions with the utility functions in |
199 // pkg/http. | 122 // pkg/http. |
200 | 123 |
201 /// Like [String.split], but only splits on the first occurrence of the pattern. | 124 /// Like [String.split], but only splits on the first occurrence of the pattern. |
202 /// This will always return an array of two elements or fewer. | 125 /// This will always return an array of two elements or fewer. |
203 List<String> split1(String toSplit, String pattern) { | 126 List<String> split1(String toSplit, String pattern) { |
204 if (toSplit.isEmpty) return <String>[]; | 127 if (toSplit.isEmpty) return <String>[]; |
205 | 128 |
206 var index = toSplit.indexOf(pattern); | 129 var index = toSplit.indexOf(pattern); |
207 if (index == -1) return [toSplit]; | 130 if (index == -1) return [toSplit]; |
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247 | 170 |
248 /// Add all key/value pairs from [source] to [destination], overwriting any | 171 /// Add all key/value pairs from [source] to [destination], overwriting any |
249 /// pre-existing values. | 172 /// pre-existing values. |
250 void mapAddAll(Map destination, Map source) => | 173 void mapAddAll(Map destination, Map source) => |
251 source.forEach((key, value) => destination[key] = value); | 174 source.forEach((key, value) => destination[key] = value); |
252 | 175 |
253 /// Decodes a URL-encoded string. Unlike [decodeUriComponent], this includes | 176 /// Decodes a URL-encoded string. Unlike [decodeUriComponent], this includes |
254 /// replacing `+` with ` `. | 177 /// replacing `+` with ` `. |
255 String urlDecode(String encoded) => | 178 String urlDecode(String encoded) => |
256 decodeUriComponent(encoded.replaceAll("+", " ")); | 179 decodeUriComponent(encoded.replaceAll("+", " ")); |
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