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| 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 | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 part of dart.async; | |
| 6 | |
| 7 class _BroadcastStream<T> extends _ControllerStream<T> { | |
| 8 _BroadcastStream(_StreamControllerLifecycle<T> controller) | |
| 9 : super(controller); | |
| 10 | |
| 11 bool get isBroadcast => true; | |
| 12 } | |
| 13 | |
| 14 class _BroadcastSubscription<T> extends _ControllerSubscription<T> { | |
| 15 static const int _STATE_EVENT_ID = 1; | |
| 16 static const int _STATE_FIRING = 2; | |
| 17 static const int _STATE_REMOVE_AFTER_FIRING = 4; | |
| 18 // TODO(lrn): Use the _state field on _ControllerSubscription to | |
| 19 // also store this state. Requires that the subscription implementation | |
| 20 // does not assume that it's use of the state integer is the only use. | |
| 21 int _eventState = 0; // Initialized to help dart2js type inference. | |
| 22 | |
| 23 _BroadcastSubscription<T> _next; | |
| 24 _BroadcastSubscription<T> _previous; | |
| 25 | |
| 26 _BroadcastSubscription(_StreamControllerLifecycle<T> controller, | |
| 27 void onData(T data), | |
| 28 Function onError, | |
| 29 void onDone(), | |
| 30 bool cancelOnError) | |
| 31 : super(controller, onData, onError, onDone, cancelOnError) { | |
| 32 _next = _previous = this; | |
| 33 } | |
| 34 | |
| 35 bool _expectsEvent(int eventId) => | |
| 36 (_eventState & _STATE_EVENT_ID) == eventId; | |
| 37 | |
| 38 void _toggleEventId() { | |
| 39 _eventState ^= _STATE_EVENT_ID; | |
| 40 } | |
| 41 | |
| 42 bool get _isFiring => (_eventState & _STATE_FIRING) != 0; | |
| 43 | |
| 44 void _setRemoveAfterFiring() { | |
| 45 assert(_isFiring); | |
| 46 _eventState |= _STATE_REMOVE_AFTER_FIRING; | |
| 47 } | |
| 48 | |
| 49 bool get _removeAfterFiring => | |
| 50 (_eventState & _STATE_REMOVE_AFTER_FIRING) != 0; | |
| 51 | |
| 52 // The controller._recordPause doesn't do anything for a broadcast controller, | |
| 53 // so we don't bother calling it. | |
| 54 void _onPause() { } | |
| 55 | |
| 56 // The controller._recordResume doesn't do anything for a broadcast | |
| 57 // controller, so we don't bother calling it. | |
| 58 void _onResume() { } | |
| 59 | |
| 60 // _onCancel is inherited. | |
| 61 } | |
| 62 | |
| 63 abstract class _BroadcastStreamController<T> | |
| 64 implements StreamController<T>, | |
| 65 _StreamControllerLifecycle<T>, | |
| 66 _EventSink<T>, | |
| 67 _EventDispatch<T> { | |
| 68 static const int _STATE_INITIAL = 0; | |
| 69 static const int _STATE_EVENT_ID = 1; | |
| 70 static const int _STATE_FIRING = 2; | |
| 71 static const int _STATE_CLOSED = 4; | |
| 72 static const int _STATE_ADDSTREAM = 8; | |
| 73 | |
| 74 ControllerCallback onListen; | |
| 75 ControllerCancelCallback onCancel; | |
| 76 | |
| 77 // State of the controller. | |
| 78 int _state; | |
| 79 | |
| 80 // Double-linked list of active listeners. | |
| 81 _BroadcastSubscription<T> _firstSubscription; | |
| 82 _BroadcastSubscription<T> _lastSubscription; | |
| 83 | |
| 84 // Extra state used during an [addStream] call. | |
| 85 _AddStreamState<T> _addStreamState; | |
| 86 | |
| 87 /** | |
| 88 * Future returned by [close] and [done]. | |
| 89 * | |
| 90 * The future is completed whenever the done event has been sent to all | |
| 91 * relevant listeners. | |
| 92 * The relevant listeners are the ones that were listening when [close] was | |
| 93 * called. When all of these have been canceled (sending the done event makes | |
| 94 * them cancel, but they can also be canceled before sending the event), | |
| 95 * this future completes. | |
| 96 * | |
| 97 * Any attempt to listen after calling [close] will throw, so there won't | |
| 98 * be any further listeners. | |
| 99 */ | |
| 100 _Future _doneFuture; | |
| 101 | |
| 102 _BroadcastStreamController(this.onListen, this.onCancel) | |
| 103 : _state = _STATE_INITIAL; | |
| 104 | |
| 105 ControllerCallback get onPause { | |
| 106 throw new UnsupportedError( | |
| 107 "Broadcast stream controllers do not support pause callbacks"); | |
| 108 } | |
| 109 | |
| 110 void set onPause(void onPauseHandler()) { | |
| 111 throw new UnsupportedError( | |
| 112 "Broadcast stream controllers do not support pause callbacks"); | |
| 113 } | |
| 114 | |
| 115 ControllerCallback get onResume { | |
| 116 throw new UnsupportedError( | |
| 117 "Broadcast stream controllers do not support pause callbacks"); | |
| 118 } | |
| 119 | |
| 120 void set onResume(void onResumeHandler()) { | |
| 121 throw new UnsupportedError( | |
| 122 "Broadcast stream controllers do not support pause callbacks"); | |
| 123 } | |
| 124 | |
| 125 // StreamController interface. | |
| 126 | |
| 127 Stream<T> get stream => new _BroadcastStream<T>(this); | |
| 128 | |
| 129 StreamSink<T> get sink => new _StreamSinkWrapper<T>(this); | |
| 130 | |
| 131 bool get isClosed => (_state & _STATE_CLOSED) != 0; | |
| 132 | |
| 133 /** | |
| 134 * A broadcast controller is never paused. | |
| 135 * | |
| 136 * Each receiving stream may be paused individually, and they handle their | |
| 137 * own buffering. | |
| 138 */ | |
| 139 bool get isPaused => false; | |
| 140 | |
| 141 /** Whether there are currently one or more subscribers. */ | |
| 142 bool get hasListener => !_isEmpty; | |
| 143 | |
| 144 /** | |
| 145 * Test whether the stream has exactly one listener. | |
| 146 * | |
| 147 * Assumes that the stream has a listener (not [_isEmpty]). | |
| 148 */ | |
| 149 bool get _hasOneListener { | |
| 150 assert(!_isEmpty); | |
| 151 return identical(_firstSubscription, _lastSubscription); | |
| 152 } | |
| 153 | |
| 154 /** Whether an event is being fired (sent to some, but not all, listeners). */ | |
| 155 bool get _isFiring => (_state & _STATE_FIRING) != 0; | |
| 156 | |
| 157 bool get _isAddingStream => (_state & _STATE_ADDSTREAM) != 0; | |
| 158 | |
| 159 bool get _mayAddEvent => (_state < _STATE_CLOSED); | |
| 160 | |
| 161 _Future _ensureDoneFuture() { | |
| 162 if (_doneFuture != null) return _doneFuture; | |
| 163 return _doneFuture = new _Future(); | |
| 164 } | |
| 165 | |
| 166 // Linked list helpers | |
| 167 | |
| 168 bool get _isEmpty => _firstSubscription == null; | |
| 169 | |
| 170 /** Adds subscription to linked list of active listeners. */ | |
| 171 void _addListener(_BroadcastSubscription<T> subscription) { | |
| 172 assert(identical(subscription._next, subscription)); | |
| 173 subscription._eventState = (_state & _STATE_EVENT_ID); | |
| 174 // Insert in linked list as last subscription. | |
| 175 _BroadcastSubscription<T> oldLast = _lastSubscription; | |
| 176 _lastSubscription = subscription; | |
| 177 subscription._next = null; | |
| 178 subscription._previous = oldLast; | |
| 179 if (oldLast == null) { | |
| 180 _firstSubscription = subscription; | |
| 181 } else { | |
| 182 oldLast._next = subscription; | |
| 183 } | |
| 184 } | |
| 185 | |
| 186 void _removeListener(_BroadcastSubscription<T> subscription) { | |
| 187 assert(identical(subscription._controller, this)); | |
| 188 assert(!identical(subscription._next, subscription)); | |
| 189 _BroadcastSubscription<T> previous = subscription._previous; | |
| 190 _BroadcastSubscription<T> next = subscription._next; | |
| 191 if (previous == null) { | |
| 192 // This was the first subscription. | |
| 193 _firstSubscription = next; | |
| 194 } else { | |
| 195 previous._next = next; | |
| 196 } | |
| 197 if (next == null) { | |
| 198 // This was the last subscription. | |
| 199 _lastSubscription = previous; | |
| 200 } else { | |
| 201 next._previous = previous; | |
| 202 } | |
| 203 | |
| 204 subscription._next = subscription._previous = subscription; | |
| 205 } | |
| 206 | |
| 207 // _StreamControllerLifecycle interface. | |
| 208 | |
| 209 StreamSubscription<T> _subscribe( | |
| 210 void onData(T data), | |
| 211 Function onError, | |
| 212 void onDone(), | |
| 213 bool cancelOnError) { | |
| 214 if (isClosed) { | |
| 215 if (onDone == null) onDone = _nullDoneHandler; | |
| 216 return new _DoneStreamSubscription<T>(onDone); | |
| 217 } | |
| 218 StreamSubscription<T> subscription = | |
| 219 new _BroadcastSubscription<T>(this, onData, onError, onDone, | |
| 220 cancelOnError); | |
| 221 _addListener(subscription); | |
| 222 if (identical(_firstSubscription, _lastSubscription)) { | |
| 223 // Only one listener, so it must be the first listener. | |
| 224 _runGuarded(onListen); | |
| 225 } | |
| 226 return subscription; | |
| 227 } | |
| 228 | |
| 229 Future _recordCancel(StreamSubscription<T> sub) { | |
| 230 _BroadcastSubscription<T> subscription = sub; | |
| 231 // If already removed by the stream, don't remove it again. | |
| 232 if (identical(subscription._next, subscription)) return null; | |
| 233 if (subscription._isFiring) { | |
| 234 subscription._setRemoveAfterFiring(); | |
| 235 } else { | |
| 236 _removeListener(subscription); | |
| 237 // If we are currently firing an event, the empty-check is performed at | |
| 238 // the end of the listener loop instead of here. | |
| 239 if (!_isFiring && _isEmpty) { | |
| 240 _callOnCancel(); | |
| 241 } | |
| 242 } | |
| 243 return null; | |
| 244 } | |
| 245 | |
| 246 void _recordPause(StreamSubscription<T> subscription) {} | |
| 247 void _recordResume(StreamSubscription<T> subscription) {} | |
| 248 | |
| 249 // EventSink interface. | |
| 250 | |
| 251 Error _addEventError() { | |
| 252 if (isClosed) { | |
| 253 return new StateError("Cannot add new events after calling close"); | |
| 254 } | |
| 255 assert(_isAddingStream); | |
| 256 return new StateError("Cannot add new events while doing an addStream"); | |
| 257 } | |
| 258 | |
| 259 void add(T data) { | |
| 260 if (!_mayAddEvent) throw _addEventError(); | |
| 261 _sendData(data); | |
| 262 } | |
| 263 | |
| 264 void addError(Object error, [StackTrace stackTrace]) { | |
| 265 error = _nonNullError(error); | |
| 266 if (!_mayAddEvent) throw _addEventError(); | |
| 267 AsyncError replacement = Zone.current.errorCallback(error, stackTrace); | |
| 268 if (replacement != null) { | |
| 269 error = _nonNullError(replacement.error); | |
| 270 stackTrace = replacement.stackTrace; | |
| 271 } | |
| 272 _sendError(error, stackTrace); | |
| 273 } | |
| 274 | |
| 275 Future close() { | |
| 276 if (isClosed) { | |
| 277 assert(_doneFuture != null); | |
| 278 return _doneFuture; | |
| 279 } | |
| 280 if (!_mayAddEvent) throw _addEventError(); | |
| 281 _state |= _STATE_CLOSED; | |
| 282 Future doneFuture = _ensureDoneFuture(); | |
| 283 _sendDone(); | |
| 284 return doneFuture; | |
| 285 } | |
| 286 | |
| 287 Future get done => _ensureDoneFuture(); | |
| 288 | |
| 289 Future addStream(Stream<T> stream, {bool cancelOnError: true}) { | |
| 290 if (!_mayAddEvent) throw _addEventError(); | |
| 291 _state |= _STATE_ADDSTREAM; | |
| 292 _addStreamState = new _AddStreamState(this, stream, cancelOnError); | |
| 293 return _addStreamState.addStreamFuture; | |
| 294 } | |
| 295 | |
| 296 // _EventSink interface, called from AddStreamState. | |
| 297 void _add(T data) { | |
| 298 _sendData(data); | |
| 299 } | |
| 300 | |
| 301 void _addError(Object error, StackTrace stackTrace) { | |
| 302 _sendError(error, stackTrace); | |
| 303 } | |
| 304 | |
| 305 void _close() { | |
| 306 assert(_isAddingStream); | |
| 307 _AddStreamState addState = _addStreamState; | |
| 308 _addStreamState = null; | |
| 309 _state &= ~_STATE_ADDSTREAM; | |
| 310 addState.complete(); | |
| 311 } | |
| 312 | |
| 313 // Event handling. | |
| 314 void _forEachListener( | |
| 315 void action(_BufferingStreamSubscription<T> subscription)) { | |
| 316 if (_isFiring) { | |
| 317 throw new StateError( | |
| 318 "Cannot fire new event. Controller is already firing an event"); | |
| 319 } | |
| 320 if (_isEmpty) return; | |
| 321 | |
| 322 // Get event id of this event. | |
| 323 int id = (_state & _STATE_EVENT_ID); | |
| 324 // Start firing (set the _STATE_FIRING bit). We don't do [onCancel] | |
| 325 // callbacks while firing, and we prevent reentrancy of this function. | |
| 326 // | |
| 327 // Set [_state]'s event id to the next event's id. | |
| 328 // Any listeners added while firing this event will expect the next event, | |
| 329 // not this one, and won't get notified. | |
| 330 _state ^= _STATE_EVENT_ID | _STATE_FIRING; | |
| 331 _BroadcastSubscription<T> subscription = _firstSubscription; | |
| 332 while (subscription != null) { | |
| 333 if (subscription._expectsEvent(id)) { | |
| 334 subscription._eventState |= _BroadcastSubscription._STATE_FIRING; | |
| 335 action(subscription); | |
| 336 subscription._toggleEventId(); | |
| 337 _BroadcastSubscription<T> next = subscription._next; | |
| 338 if (subscription._removeAfterFiring) { | |
| 339 _removeListener(subscription); | |
| 340 } | |
| 341 subscription._eventState &= ~_BroadcastSubscription._STATE_FIRING; | |
| 342 subscription = next; | |
| 343 } else { | |
| 344 subscription = subscription._next; | |
| 345 } | |
| 346 } | |
| 347 _state &= ~_STATE_FIRING; | |
| 348 | |
| 349 if (_isEmpty) { | |
| 350 _callOnCancel(); | |
| 351 } | |
| 352 } | |
| 353 | |
| 354 void _callOnCancel() { | |
| 355 assert(_isEmpty); | |
| 356 if (isClosed && _doneFuture._mayComplete) { | |
| 357 // When closed, _doneFuture is not null. | |
| 358 _doneFuture._asyncComplete(null); | |
| 359 } | |
| 360 _runGuarded(onCancel); | |
| 361 } | |
| 362 } | |
| 363 | |
| 364 class _SyncBroadcastStreamController<T> extends _BroadcastStreamController<T> | |
| 365 implements SynchronousStreamController<T> { | |
| 366 _SyncBroadcastStreamController(void onListen(), void onCancel()) | |
| 367 : super(onListen, onCancel); | |
| 368 | |
| 369 // EventDispatch interface. | |
| 370 | |
| 371 bool get _mayAddEvent => super._mayAddEvent && !_isFiring; | |
| 372 | |
| 373 _addEventError() { | |
| 374 if (_isFiring) { | |
| 375 return new StateError( | |
| 376 "Cannot fire new event. Controller is already firing an event"); | |
| 377 } | |
| 378 return super._addEventError(); | |
| 379 } | |
| 380 | |
| 381 void _sendData(T data) { | |
| 382 if (_isEmpty) return; | |
| 383 if (_hasOneListener) { | |
| 384 _state |= _BroadcastStreamController._STATE_FIRING; | |
| 385 _BroadcastSubscription<T> subscription = _firstSubscription; | |
| 386 subscription._add(data); | |
| 387 _state &= ~_BroadcastStreamController._STATE_FIRING; | |
| 388 if (_isEmpty) { | |
| 389 _callOnCancel(); | |
| 390 } | |
| 391 return; | |
| 392 } | |
| 393 _forEachListener((_BufferingStreamSubscription<T> subscription) { | |
| 394 subscription._add(data); | |
| 395 }); | |
| 396 } | |
| 397 | |
| 398 void _sendError(Object error, StackTrace stackTrace) { | |
| 399 if (_isEmpty) return; | |
| 400 _forEachListener((_BufferingStreamSubscription<T> subscription) { | |
| 401 subscription._addError(error, stackTrace); | |
| 402 }); | |
| 403 } | |
| 404 | |
| 405 void _sendDone() { | |
| 406 if (!_isEmpty) { | |
| 407 _forEachListener((_BufferingStreamSubscription<T> subscription) { | |
| 408 subscription._close(); | |
| 409 }); | |
| 410 } else { | |
| 411 assert(_doneFuture != null); | |
| 412 assert(_doneFuture._mayComplete); | |
| 413 _doneFuture._asyncComplete(null); | |
| 414 } | |
| 415 } | |
| 416 } | |
| 417 | |
| 418 class _AsyncBroadcastStreamController<T> extends _BroadcastStreamController<T> { | |
| 419 _AsyncBroadcastStreamController(void onListen(), void onCancel()) | |
| 420 : super(onListen, onCancel); | |
| 421 | |
| 422 // EventDispatch interface. | |
| 423 | |
| 424 void _sendData(T data) { | |
| 425 for (_BroadcastSubscription<T> subscription = _firstSubscription; | |
| 426 subscription != null; | |
| 427 subscription = subscription._next) { | |
| 428 subscription._addPending(new _DelayedData<T>(data)); | |
| 429 } | |
| 430 } | |
| 431 | |
| 432 void _sendError(Object error, StackTrace stackTrace) { | |
| 433 for (_BroadcastSubscription<T> subscription = _firstSubscription; | |
| 434 subscription != null; | |
| 435 subscription = subscription._next) { | |
| 436 subscription._addPending(new _DelayedError(error, stackTrace)); | |
| 437 } | |
| 438 } | |
| 439 | |
| 440 void _sendDone() { | |
| 441 if (!_isEmpty) { | |
| 442 for (_BroadcastSubscription<T> subscription = _firstSubscription; | |
| 443 subscription != null; | |
| 444 subscription = subscription._next) { | |
| 445 subscription._addPending(const _DelayedDone()); | |
| 446 } | |
| 447 } else { | |
| 448 assert(_doneFuture != null); | |
| 449 assert(_doneFuture._mayComplete); | |
| 450 _doneFuture._asyncComplete(null); | |
| 451 } | |
| 452 } | |
| 453 } | |
| 454 | |
| 455 /** | |
| 456 * Stream controller that is used by [Stream.asBroadcastStream]. | |
| 457 * | |
| 458 * This stream controller allows incoming events while it is firing | |
| 459 * other events. This is handled by delaying the events until the | |
| 460 * current event is done firing, and then fire the pending events. | |
| 461 * | |
| 462 * This class extends [_SyncBroadcastStreamController]. Events of | |
| 463 * an "asBroadcastStream" stream are always initiated by events | |
| 464 * on another stream, and it is fine to forward them synchronously. | |
| 465 */ | |
| 466 class _AsBroadcastStreamController<T> | |
| 467 extends _SyncBroadcastStreamController<T> | |
| 468 implements _EventDispatch<T> { | |
| 469 _StreamImplEvents<T> _pending; | |
| 470 | |
| 471 _AsBroadcastStreamController(void onListen(), void onCancel()) | |
| 472 : super(onListen, onCancel); | |
| 473 | |
| 474 bool get _hasPending => _pending != null && ! _pending.isEmpty; | |
| 475 | |
| 476 void _addPendingEvent(_DelayedEvent event) { | |
| 477 if (_pending == null) { | |
| 478 _pending = new _StreamImplEvents<T>(); | |
| 479 } | |
| 480 _pending.add(event); | |
| 481 } | |
| 482 | |
| 483 void add(T data) { | |
| 484 if (!isClosed && _isFiring) { | |
| 485 _addPendingEvent(new _DelayedData<T>(data)); | |
| 486 return; | |
| 487 } | |
| 488 super.add(data); | |
| 489 while (_hasPending) { | |
| 490 _pending.handleNext(this); | |
| 491 } | |
| 492 } | |
| 493 | |
| 494 void addError(Object error, [StackTrace stackTrace]) { | |
| 495 if (!isClosed && _isFiring) { | |
| 496 _addPendingEvent(new _DelayedError(error, stackTrace)); | |
| 497 return; | |
| 498 } | |
| 499 if (!_mayAddEvent) throw _addEventError(); | |
| 500 _sendError(error, stackTrace); | |
| 501 while (_hasPending) { | |
| 502 _pending.handleNext(this); | |
| 503 } | |
| 504 } | |
| 505 | |
| 506 Future close() { | |
| 507 if (!isClosed && _isFiring) { | |
| 508 _addPendingEvent(const _DelayedDone()); | |
| 509 _state |= _BroadcastStreamController._STATE_CLOSED; | |
| 510 return super.done; | |
| 511 } | |
| 512 Future result = super.close(); | |
| 513 assert(!_hasPending); | |
| 514 return result; | |
| 515 } | |
| 516 | |
| 517 void _callOnCancel() { | |
| 518 if (_hasPending) { | |
| 519 _pending.clear(); | |
| 520 _pending = null; | |
| 521 } | |
| 522 super._callOnCancel(); | |
| 523 } | |
| 524 } | |
| 525 | |
| 526 // A subscription that never receives any events. | |
| 527 // It can simulate pauses, but otherwise does nothing. | |
| 528 class _DoneSubscription<T> implements StreamSubscription<T> { | |
| 529 int _pauseCount = 0; | |
| 530 void onData(void handleData(T data)) {} | |
| 531 void onError(Function handleError) {} | |
| 532 void onDone(void handleDone()) {} | |
| 533 void pause([Future resumeSignal]) { | |
| 534 if (resumeSignal != null) resumeSignal.then(_resume); | |
| 535 _pauseCount++; | |
| 536 } | |
| 537 void resume() { _resume(null); } | |
| 538 void _resume(_) { | |
| 539 if (_pauseCount > 0) _pauseCount--; | |
| 540 } | |
| 541 Future cancel() { return new _Future.immediate(null); } | |
| 542 bool get isPaused => _pauseCount > 0; | |
| 543 Future/*<E>*/ asFuture/*<E>*/([Object/*=E*/ value]) => new _Future/*<E>*/(); | |
| 544 } | |
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Chromium Code Reviews
Issue 2698353003:
unfork DDC's copy of most SDK libraries (Closed)
