1 | // Copyright 2011 Software Freedom Conservancy. All Rights Reserved. |
2 | // |
3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
4 | // you may not use this file except in compliance with the License. |
5 | // You may obtain a copy of the License at |
6 | // |
7 | // http://www.apache.org/licenses/LICENSE-2.0 |
8 | // |
9 | // Unless required by applicable law or agreed to in writing, software |
10 | // distributed under the License is distributed on an "AS IS" BASIS, |
11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
12 | // See the License for the specific language governing permissions and |
13 | // limitations under the License. |
14 | |
15 | /** |
16 | * @license Portions of this code are from the Dojo toolkit, received under the |
17 | * BSD License: |
18 | * Redistribution and use in source and binary forms, with or without |
19 | * modification, are permitted provided that the following conditions are met: |
20 | * |
21 | * * Redistributions of source code must retain the above copyright notice, |
22 | * this list of conditions and the following disclaimer. |
23 | * * Redistributions in binary form must reproduce the above copyright notice, |
24 | * this list of conditions and the following disclaimer in the documentation |
25 | * and/or other materials provided with the distribution. |
26 | * * Neither the name of the Dojo Foundation nor the names of its contributors |
27 | * may be used to endorse or promote products derived from this software |
28 | * without specific prior written permission. |
29 | * |
30 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
31 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
32 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
33 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
34 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
35 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
36 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
37 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
38 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
39 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
40 | * POSSIBILITY OF SUCH DAMAGE. |
41 | */ |
42 | |
43 | /** |
44 | * @fileoverview A promise implementation based on the CommonJS promise/A and |
45 | * promise/B proposals. For more information, see |
46 | * http://wiki.commonjs.org/wiki/Promises. |
47 | */ |
48 | |
49 | goog.provide('webdriver.promise'); |
50 | goog.provide('webdriver.promise.ControlFlow'); |
51 | goog.provide('webdriver.promise.ControlFlow.Timer'); |
52 | goog.provide('webdriver.promise.Deferred'); |
53 | goog.provide('webdriver.promise.Promise'); |
54 | |
55 | goog.require('goog.array'); |
56 | goog.require('goog.debug.Error'); |
57 | goog.require('goog.object'); |
58 | goog.require('webdriver.EventEmitter'); |
59 | goog.require('webdriver.stacktrace.Snapshot'); |
60 | |
61 | |
62 | |
63 | /** |
64 | * Represents the eventual value of a completed operation. Each promise may be |
65 | * in one of three states: pending, resolved, or rejected. Each promise starts |
66 | * in the pending state and may make a single transition to either a |
67 | * fulfilled or failed state. |
68 | * |
69 | * <p/>This class is based on the Promise/A proposal from CommonJS. Additional |
70 | * functions are provided for API compatibility with Dojo Deferred objects. |
71 | * |
72 | * @constructor |
73 | * @see http://wiki.commonjs.org/wiki/Promises/A |
74 | */ |
75 | webdriver.promise.Promise = function() { |
76 | }; |
77 | |
78 | |
79 | /** |
80 | * Cancels the computation of this promise's value, rejecting the promise in the |
81 | * process. |
82 | * @param {*} reason The reason this promise is being cancelled. If not an |
83 | * {@code Error}, one will be created using the value's string |
84 | * representation. |
85 | */ |
86 | webdriver.promise.Promise.prototype.cancel = function(reason) { |
87 | throw new TypeError('Unimplemented function: "cancel"'); |
88 | }; |
89 | |
90 | |
91 | /** @return {boolean} Whether this promise's value is still being computed. */ |
92 | webdriver.promise.Promise.prototype.isPending = function() { |
93 | throw new TypeError('Unimplemented function: "isPending"'); |
94 | }; |
95 | |
96 | |
97 | /** |
98 | * Registers listeners for when this instance is resolved. This function most |
99 | * overridden by subtypes. |
100 | * |
101 | * @param {Function=} opt_callback The function to call if this promise is |
102 | * successfully resolved. The function should expect a single argument: the |
103 | * promise's resolved value. |
104 | * @param {Function=} opt_errback The function to call if this promise is |
105 | * rejected. The function should expect a single argument: the rejection |
106 | * reason. |
107 | * @return {!webdriver.promise.Promise} A new promise which will be resolved |
108 | * with the result of the invoked callback. |
109 | */ |
110 | webdriver.promise.Promise.prototype.then = function( |
111 | opt_callback, opt_errback) { |
112 | throw new TypeError('Unimplemented function: "then"'); |
113 | }; |
114 | |
115 | |
116 | /** |
117 | * Registers a listener for when this promise is rejected. This is synonymous |
118 | * with the {@code catch} clause in a synchronous API: |
119 | * <pre><code> |
120 | * // Synchronous API: |
121 | * try { |
122 | * doSynchronousWork(); |
123 | * } catch (ex) { |
124 | * console.error(ex); |
125 | * } |
126 | * |
127 | * // Asynchronous promise API: |
128 | * doAsynchronousWork().thenCatch(function(ex) { |
129 | * console.error(ex); |
130 | * }); |
131 | * </code></pre> |
132 | * |
133 | * @param {!Function} errback The function to call if this promise is |
134 | * rejected. The function should expect a single argument: the rejection |
135 | * reason. |
136 | * @return {!webdriver.promise.Promise} A new promise which will be resolved |
137 | * with the result of the invoked callback. |
138 | */ |
139 | webdriver.promise.Promise.prototype.thenCatch = function(errback) { |
140 | return this.then(null, errback); |
141 | }; |
142 | |
143 | |
144 | /** |
145 | * Registers a listener to invoke when this promise is resolved, regardless |
146 | * of whether the promise's value was successfully computed. This function |
147 | * is synonymous with the {@code finally} clause in a synchronous API: |
148 | * <pre><code> |
149 | * // Synchronous API: |
150 | * try { |
151 | * doSynchronousWork(); |
152 | * } finally { |
153 | * cleanUp(); |
154 | * } |
155 | * |
156 | * // Asynchronous promise API: |
157 | * doAsynchronousWork().thenFinally(cleanUp); |
158 | * </code></pre> |
159 | * |
160 | * <b>Note:</b> similar to the {@code finally} clause, if the registered |
161 | * callback returns a rejected promise or throws an error, it will silently |
162 | * replace the rejection error (if any) from this promise: |
163 | * <pre><code> |
164 | * try { |
165 | * throw Error('one'); |
166 | * } finally { |
167 | * throw Error('two'); // Hides Error: one |
168 | * } |
169 | * |
170 | * webdriver.promise.rejected(Error('one')) |
171 | * .thenFinally(function() { |
172 | * throw Error('two'); // Hides Error: one |
173 | * }); |
174 | * </code></pre> |
175 | * |
176 | * |
177 | * @param callback |
178 | * @returns {!webdriver.promise.Promise} |
179 | */ |
180 | webdriver.promise.Promise.prototype.thenFinally = function(callback) { |
181 | return this.then(callback, callback); |
182 | }; |
183 | |
184 | |
185 | /** |
186 | * Registers a function to be invoked when this promise is successfully |
187 | * resolved. This function is provided for backwards compatibility with the |
188 | * Dojo Deferred API. |
189 | * |
190 | * @param {Function} callback The function to call if this promise is |
191 | * successfully resolved. The function should expect a single argument: the |
192 | * promise's resolved value. |
193 | * @param {!Object=} opt_self The object which |this| should refer to when the |
194 | * function is invoked. |
195 | * @return {!webdriver.promise.Promise} A new promise which will be resolved |
196 | * with the result of the invoked callback. |
197 | * @deprecated Use {@link #then()} instead. |
198 | */ |
199 | webdriver.promise.Promise.prototype.addCallback = function(callback, opt_self) { |
200 | return this.then(goog.bind(callback, opt_self)); |
201 | }; |
202 | |
203 | |
204 | /** |
205 | * Registers a function to be invoked when this promise is rejected. |
206 | * This function is provided for backwards compatibility with the |
207 | * Dojo Deferred API. |
208 | * |
209 | * @param {Function} errback The function to call if this promise is |
210 | * rejected. The function should expect a single argument: the rejection |
211 | * reason. |
212 | * @param {!Object=} opt_self The object which |this| should refer to when the |
213 | * function is invoked. |
214 | * @return {!webdriver.promise.Promise} A new promise which will be resolved |
215 | * with the result of the invoked callback. |
216 | * @deprecated Use {@link #thenCatch()} instead. |
217 | */ |
218 | webdriver.promise.Promise.prototype.addErrback = function(errback, opt_self) { |
219 | return this.thenCatch(goog.bind(errback, opt_self)); |
220 | }; |
221 | |
222 | |
223 | /** |
224 | * Registers a function to be invoked when this promise is either rejected or |
225 | * resolved. This function is provided for backwards compatibility with the |
226 | * Dojo Deferred API. |
227 | * |
228 | * @param {Function} callback The function to call when this promise is |
229 | * either resolved or rejected. The function should expect a single |
230 | * argument: the resolved value or rejection error. |
231 | * @param {!Object=} opt_self The object which |this| should refer to when the |
232 | * function is invoked. |
233 | * @return {!webdriver.promise.Promise} A new promise which will be resolved |
234 | * with the result of the invoked callback. |
235 | * @deprecated Use {@link #thenFinally()} instead. |
236 | */ |
237 | webdriver.promise.Promise.prototype.addBoth = function(callback, opt_self) { |
238 | return this.thenFinally(goog.bind(callback, opt_self)); |
239 | }; |
240 | |
241 | |
242 | /** |
243 | * An alias for {@code webdriver.promise.Promise.prototype.then} that permits |
244 | * the scope of the invoked function to be specified. This function is provided |
245 | * for backwards compatibility with the Dojo Deferred API. |
246 | * |
247 | * @param {Function} callback The function to call if this promise is |
248 | * successfully resolved. The function should expect a single argument: the |
249 | * promise's resolved value. |
250 | * @param {Function} errback The function to call if this promise is |
251 | * rejected. The function should expect a single argument: the rejection |
252 | * reason. |
253 | * @param {!Object=} opt_self The object which |this| should refer to when the |
254 | * function is invoked. |
255 | * @return {!webdriver.promise.Promise} A new promise which will be resolved |
256 | * with the result of the invoked callback. |
257 | * @deprecated Use {@link #then()} instead. |
258 | */ |
259 | webdriver.promise.Promise.prototype.addCallbacks = function( |
260 | callback, errback, opt_self) { |
261 | return this.then(goog.bind(callback, opt_self), |
262 | goog.bind(errback, opt_self)); |
263 | }; |
264 | |
265 | |
266 | |
267 | /** |
268 | * Represents a value that will be resolved at some point in the future. This |
269 | * class represents the protected "producer" half of a Promise - each Deferred |
270 | * has a {@code promise} property that may be returned to consumers for |
271 | * registering callbacks, reserving the ability to resolve the deferred to the |
272 | * producer. |
273 | * |
274 | * <p>If this Deferred is rejected and there are no listeners registered before |
275 | * the next turn of the event loop, the rejection will be passed to the |
276 | * {@link webdriver.promise.ControlFlow} as an unhandled failure. |
277 | * |
278 | * <p>If this Deferred is cancelled, the cancellation reason will be forward to |
279 | * the Deferred's canceller function (if provided). The canceller may return a |
280 | * truth-y value to override the reason provided for rejection. |
281 | * |
282 | * @param {Function=} opt_canceller Function to call when cancelling the |
283 | * computation of this instance's value. |
284 | * @param {webdriver.promise.ControlFlow=} opt_flow The control flow |
285 | * this instance was created under. This should only be provided during |
286 | * unit tests. |
287 | * @constructor |
288 | * @extends {webdriver.promise.Promise} |
289 | */ |
290 | webdriver.promise.Deferred = function(opt_canceller, opt_flow) { |
291 | /* NOTE: This class's implementation diverges from the prototypical style |
292 | * used in the rest of the atoms library. This was done intentionally to |
293 | * protect the internal Deferred state from consumers, as outlined by |
294 | * http://wiki.commonjs.org/wiki/Promises |
295 | */ |
296 | goog.base(this); |
297 | |
298 | var flow = opt_flow || webdriver.promise.controlFlow(); |
299 | |
300 | /** |
301 | * The listeners registered with this Deferred. Each element in the list will |
302 | * be a 3-tuple of the callback function, errback function, and the |
303 | * corresponding deferred object. |
304 | * @type {!Array.<!webdriver.promise.Deferred.Listener_>} |
305 | */ |
306 | var listeners = []; |
307 | |
308 | /** |
309 | * Whether this Deferred's resolution was ever handled by a listener. |
310 | * If the Deferred is rejected and its value is not handled by a listener |
311 | * before the next turn of the event loop, the error will be passed to the |
312 | * global error handler. |
313 | * @type {boolean} |
314 | */ |
315 | var handled = false; |
316 | |
317 | /** |
318 | * Key for the timeout used to delay reproting an unhandled rejection to the |
319 | * parent {@link webdriver.promise.ControlFlow}. |
320 | * @type {?number} |
321 | */ |
322 | var pendingRejectionKey = null; |
323 | |
324 | /** |
325 | * This Deferred's current state. |
326 | * @type {!webdriver.promise.Deferred.State_} |
327 | */ |
328 | var state = webdriver.promise.Deferred.State_.PENDING; |
329 | |
330 | /** |
331 | * This Deferred's resolved value; set when the state transitions from |
332 | * {@code webdriver.promise.Deferred.State_.PENDING}. |
333 | * @type {*} |
334 | */ |
335 | var value; |
336 | |
337 | /** @return {boolean} Whether this promise's value is still pending. */ |
338 | function isPending() { |
339 | return state == webdriver.promise.Deferred.State_.PENDING; |
340 | } |
341 | |
342 | /** |
343 | * Removes all of the listeners previously registered on this deferred. |
344 | * @throws {Error} If this deferred has already been resolved. |
345 | */ |
346 | function removeAll() { |
347 | listeners = []; |
348 | } |
349 | |
350 | /** |
351 | * Resolves this deferred. If the new value is a promise, this function will |
352 | * wait for it to be resolved before notifying the registered listeners. |
353 | * @param {!webdriver.promise.Deferred.State_} newState The deferred's new |
354 | * state. |
355 | * @param {*} newValue The deferred's new value. |
356 | */ |
357 | function resolve(newState, newValue) { |
358 | if (webdriver.promise.Deferred.State_.PENDING !== state) { |
359 | return; |
360 | } |
361 | |
362 | state = webdriver.promise.Deferred.State_.BLOCKED; |
363 | |
364 | if (webdriver.promise.isPromise(newValue) && newValue !== self) { |
365 | var onFulfill = goog.partial(notifyAll, newState); |
366 | var onReject = goog.partial( |
367 | notifyAll, webdriver.promise.Deferred.State_.REJECTED); |
368 | if (newValue instanceof webdriver.promise.Deferred) { |
369 | newValue.then(onFulfill, onReject); |
370 | } else { |
371 | webdriver.promise.asap(newValue, onFulfill, onReject); |
372 | } |
373 | |
374 | } else { |
375 | notifyAll(newState, newValue); |
376 | } |
377 | } |
378 | |
379 | /** |
380 | * Notifies all of the listeners registered with this Deferred that its state |
381 | * has changed. |
382 | * @param {!webdriver.promise.Deferred.State_} newState The deferred's new |
383 | * state. |
384 | * @param {*} newValue The deferred's new value. |
385 | */ |
386 | function notifyAll(newState, newValue) { |
387 | if (newState === webdriver.promise.Deferred.State_.REJECTED && |
388 | // We cannot check instanceof Error since the object may have been |
389 | // created in a different JS context. |
390 | goog.isObject(newValue) && goog.isString(newValue.message)) { |
391 | newValue = flow.annotateError(/** @type {!Error} */(newValue)); |
392 | } |
393 | |
394 | state = newState; |
395 | value = newValue; |
396 | while (listeners.length) { |
397 | notify(listeners.shift()); |
398 | } |
399 | |
400 | if (!handled && state == webdriver.promise.Deferred.State_.REJECTED) { |
401 | pendingRejectionKey = propagateError(value); |
402 | } |
403 | } |
404 | |
405 | /** |
406 | * Propagates an unhandled rejection to the parent ControlFlow in a |
407 | * future turn of the JavaScript event loop. |
408 | * @param {*} error The error value to report. |
409 | * @return {number} The key for the registered timeout. |
410 | */ |
411 | function propagateError(error) { |
412 | flow.pendingRejections_ += 1; |
413 | return flow.timer.setTimeout(function() { |
414 | flow.pendingRejections_ -= 1; |
415 | flow.abortFrame_(error); |
416 | }, 0); |
417 | } |
418 | |
419 | /** |
420 | * Notifies a single listener of this Deferred's change in state. |
421 | * @param {!webdriver.promise.Deferred.Listener_} listener The listener to |
422 | * notify. |
423 | */ |
424 | function notify(listener) { |
425 | var func = state == webdriver.promise.Deferred.State_.RESOLVED ? |
426 | listener.callback : listener.errback; |
427 | if (func) { |
428 | flow.runInNewFrame_(goog.partial(func, value), |
429 | listener.fulfill, listener.reject); |
430 | } else if (state == webdriver.promise.Deferred.State_.REJECTED) { |
431 | listener.reject(value); |
432 | } else { |
433 | listener.fulfill(value); |
434 | } |
435 | } |
436 | |
437 | /** |
438 | * The consumer promise for this instance. Provides protected access to the |
439 | * callback registering functions. |
440 | * @type {!webdriver.promise.Promise} |
441 | */ |
442 | var promise = new webdriver.promise.Promise(); |
443 | |
444 | /** |
445 | * Registers a callback on this Deferred. |
446 | * @param {Function=} opt_callback The callback. |
447 | * @param {Function=} opt_errback The errback. |
448 | * @return {!webdriver.promise.Promise} A new promise representing the result |
449 | * of the callback. |
450 | * @see webdriver.promise.Promise#then |
451 | */ |
452 | function then(opt_callback, opt_errback) { |
453 | // Avoid unnecessary allocations if we weren't given any callback functions. |
454 | if (!opt_callback && !opt_errback) { |
455 | return promise; |
456 | } |
457 | |
458 | // The moment a listener is registered, we consider this deferred to be |
459 | // handled; the callback must handle any rejection errors. |
460 | handled = true; |
461 | if (pendingRejectionKey) { |
462 | flow.pendingRejections_ -= 1; |
463 | flow.timer.clearTimeout(pendingRejectionKey); |
464 | } |
465 | |
466 | var deferred = new webdriver.promise.Deferred(cancel, flow); |
467 | var listener = { |
468 | callback: opt_callback, |
469 | errback: opt_errback, |
470 | fulfill: deferred.fulfill, |
471 | reject: deferred.reject |
472 | }; |
473 | |
474 | if (state == webdriver.promise.Deferred.State_.PENDING || |
475 | state == webdriver.promise.Deferred.State_.BLOCKED) { |
476 | listeners.push(listener); |
477 | } else { |
478 | notify(listener); |
479 | } |
480 | |
481 | return deferred.promise; |
482 | } |
483 | |
484 | var self = this; |
485 | |
486 | /** |
487 | * Resolves this promise with the given value. If the value is itself a |
488 | * promise and not a reference to this deferred, this instance will wait for |
489 | * it before resolving. |
490 | * @param {*=} opt_value The resolved value. |
491 | */ |
492 | function fulfill(opt_value) { |
493 | resolve(webdriver.promise.Deferred.State_.RESOLVED, opt_value); |
494 | } |
495 | |
496 | /** |
497 | * Rejects this promise. If the error is itself a promise, this instance will |
498 | * be chained to it and be rejected with the error's resolved value. |
499 | * @param {*=} opt_error The rejection reason, typically either a |
500 | * {@code Error} or a {@code string}. |
501 | */ |
502 | function reject(opt_error) { |
503 | resolve(webdriver.promise.Deferred.State_.REJECTED, opt_error); |
504 | } |
505 | |
506 | /** |
507 | * Attempts to cancel the computation of this instance's value. This attempt |
508 | * will silently fail if this instance has already resolved. |
509 | * @param {*=} opt_reason The reason for cancelling this promise. |
510 | */ |
511 | function cancel(opt_reason) { |
512 | if (!isPending()) { |
513 | return; |
514 | } |
515 | |
516 | if (opt_canceller) { |
517 | opt_reason = opt_canceller(opt_reason) || opt_reason; |
518 | } |
519 | |
520 | reject(opt_reason); |
521 | } |
522 | |
523 | this.promise = promise; |
524 | this.promise.then = this.then = then; |
525 | this.promise.cancel = this.cancel = cancel; |
526 | this.promise.isPending = this.isPending = isPending; |
527 | this.fulfill = fulfill; |
528 | this.reject = this.errback = reject; |
529 | |
530 | // Only expose this function to our internal classes. |
531 | // TODO: find a cleaner way of handling this. |
532 | if (this instanceof webdriver.promise.Task_) { |
533 | this.removeAll = removeAll; |
534 | } |
535 | |
536 | // Export symbols necessary for the contract on this object to work in |
537 | // compiled mode. |
538 | goog.exportProperty(this, 'then', this.then); |
539 | goog.exportProperty(this, 'cancel', cancel); |
540 | goog.exportProperty(this, 'fulfill', fulfill); |
541 | goog.exportProperty(this, 'reject', reject); |
542 | goog.exportProperty(this, 'isPending', isPending); |
543 | goog.exportProperty(this, 'promise', this.promise); |
544 | goog.exportProperty(this.promise, 'then', this.then); |
545 | goog.exportProperty(this.promise, 'cancel', cancel); |
546 | goog.exportProperty(this.promise, 'isPending', isPending); |
547 | }; |
548 | goog.inherits(webdriver.promise.Deferred, webdriver.promise.Promise); |
549 | |
550 | |
551 | /** |
552 | * Type definition for a listener registered on a Deferred object. |
553 | * @typedef {{callback:(Function|undefined), |
554 | * errback:(Function|undefined), |
555 | * fulfill: function(*), reject: function(*)}} |
556 | * @private |
557 | */ |
558 | webdriver.promise.Deferred.Listener_; |
559 | |
560 | |
561 | /** |
562 | * The three states a {@link webdriver.promise.Deferred} object may be in. |
563 | * @enum {number} |
564 | * @private |
565 | */ |
566 | webdriver.promise.Deferred.State_ = { |
567 | REJECTED: -1, |
568 | PENDING: 0, |
569 | BLOCKED: 1, |
570 | RESOLVED: 2 |
571 | }; |
572 | |
573 | |
574 | /** |
575 | * Tests if a value is an Error-like object. This is more than an straight |
576 | * instanceof check since the value may originate from another context. |
577 | * @param {*} value The value to test. |
578 | * @return {boolean} Whether the value is an error. |
579 | * @private |
580 | */ |
581 | webdriver.promise.isError_ = function(value) { |
582 | return value instanceof Error || |
583 | goog.isObject(value) && |
584 | (Object.prototype.toString.call(value) === '[object Error]' || |
585 | // A special test for goog.testing.JsUnitException. |
586 | value.isJsUnitException); |
587 | |
588 | }; |
589 | |
590 | |
591 | /** |
592 | * Determines whether a {@code value} should be treated as a promise. |
593 | * Any object whose "then" property is a function will be considered a promise. |
594 | * |
595 | * @param {*} value The value to test. |
596 | * @return {boolean} Whether the value is a promise. |
597 | */ |
598 | webdriver.promise.isPromise = function(value) { |
599 | return !!value && goog.isObject(value) && |
600 | // Use array notation so the Closure compiler does not obfuscate away our |
601 | // contract. |
602 | goog.isFunction(value['then']); |
603 | }; |
604 | |
605 | |
606 | /** |
607 | * Creates a promise that will be resolved at a set time in the future. |
608 | * @param {number} ms The amount of time, in milliseconds, to wait before |
609 | * resolving the promise. |
610 | * @return {!webdriver.promise.Promise} The promise. |
611 | */ |
612 | webdriver.promise.delayed = function(ms) { |
613 | var timer = webdriver.promise.controlFlow().timer; |
614 | var key; |
615 | var deferred = new webdriver.promise.Deferred(function() { |
616 | timer.clearTimeout(key); |
617 | }); |
618 | key = timer.setTimeout(deferred.fulfill, ms); |
619 | return deferred.promise; |
620 | }; |
621 | |
622 | |
623 | /** |
624 | * Creates a new deferred object. |
625 | * @param {Function=} opt_canceller Function to call when cancelling the |
626 | * computation of this instance's value. |
627 | * @return {!webdriver.promise.Deferred} The new deferred object. |
628 | */ |
629 | webdriver.promise.defer = function(opt_canceller) { |
630 | return new webdriver.promise.Deferred(opt_canceller); |
631 | }; |
632 | |
633 | |
634 | /** |
635 | * Creates a promise that has been resolved with the given value. |
636 | * @param {*=} opt_value The resolved value. |
637 | * @return {!webdriver.promise.Promise} The resolved promise. |
638 | */ |
639 | webdriver.promise.fulfilled = function(opt_value) { |
640 | if (opt_value instanceof webdriver.promise.Promise) { |
641 | return opt_value; |
642 | } |
643 | var deferred = new webdriver.promise.Deferred(); |
644 | deferred.fulfill(opt_value); |
645 | return deferred.promise; |
646 | }; |
647 | |
648 | |
649 | /** |
650 | * Creates a promise that has been rejected with the given reason. |
651 | * @param {*=} opt_reason The rejection reason; may be any value, but is |
652 | * usually an Error or a string. |
653 | * @return {!webdriver.promise.Promise} The rejected promise. |
654 | */ |
655 | webdriver.promise.rejected = function(opt_reason) { |
656 | var deferred = new webdriver.promise.Deferred(); |
657 | deferred.reject(opt_reason); |
658 | return deferred.promise; |
659 | }; |
660 | |
661 | |
662 | /** |
663 | * Wraps a function that is assumed to be a node-style callback as its final |
664 | * argument. This callback takes two arguments: an error value (which will be |
665 | * null if the call succeeded), and the success value as the second argument. |
666 | * If the call fails, the returned promise will be rejected, otherwise it will |
667 | * be resolved with the result. |
668 | * @param {!Function} fn The function to wrap. |
669 | * @return {!webdriver.promise.Promise} A promise that will be resolved with the |
670 | * result of the provided function's callback. |
671 | */ |
672 | webdriver.promise.checkedNodeCall = function(fn) { |
673 | var deferred = new webdriver.promise.Deferred(function() { |
674 | throw Error('This Deferred may not be cancelled'); |
675 | }); |
676 | try { |
677 | fn(function(error, value) { |
678 | error ? deferred.reject(error) : deferred.fulfill(value); |
679 | }); |
680 | } catch (ex) { |
681 | deferred.reject(ex); |
682 | } |
683 | return deferred.promise; |
684 | }; |
685 | |
686 | |
687 | /** |
688 | * Registers an observer on a promised {@code value}, returning a new promise |
689 | * that will be resolved when the value is. If {@code value} is not a promise, |
690 | * then the return promise will be immediately resolved. |
691 | * @param {*} value The value to observe. |
692 | * @param {Function=} opt_callback The function to call when the value is |
693 | * resolved successfully. |
694 | * @param {Function=} opt_errback The function to call when the value is |
695 | * rejected. |
696 | * @return {!webdriver.promise.Promise} A new promise. |
697 | */ |
698 | webdriver.promise.when = function(value, opt_callback, opt_errback) { |
699 | if (value instanceof webdriver.promise.Promise) { |
700 | return value.then(opt_callback, opt_errback); |
701 | } |
702 | |
703 | var deferred = new webdriver.promise.Deferred(); |
704 | |
705 | webdriver.promise.asap(value, deferred.fulfill, deferred.reject); |
706 | |
707 | return deferred.then(opt_callback, opt_errback); |
708 | }; |
709 | |
710 | |
711 | /** |
712 | * Invokes the appropriate callback function as soon as a promised |
713 | * {@code value} is resolved. This function is similar to |
714 | * {@link webdriver.promise.when}, except it does not return a new promise. |
715 | * @param {*} value The value to observe. |
716 | * @param {Function} callback The function to call when the value is |
717 | * resolved successfully. |
718 | * @param {Function=} opt_errback The function to call when the value is |
719 | * rejected. |
720 | */ |
721 | webdriver.promise.asap = function(value, callback, opt_errback) { |
722 | if (webdriver.promise.isPromise(value)) { |
723 | value.then(callback, opt_errback); |
724 | |
725 | // Maybe a Dojo-like deferred object? |
726 | } else if (!!value && goog.isObject(value) && |
727 | goog.isFunction(value.addCallbacks)) { |
728 | value.addCallbacks(callback, opt_errback); |
729 | |
730 | // A raw value, return a resolved promise. |
731 | } else if (callback) { |
732 | callback(value); |
733 | } |
734 | }; |
735 | |
736 | |
737 | /** |
738 | * Given an array of promises, will return a promise that will be fulfilled |
739 | * with the fulfillment values of the input array's values. If any of the |
740 | * input array's promises are rejected, the returned promise will be rejected |
741 | * with the same reason. |
742 | * |
743 | * @param {!Array.<(T|!webdriver.promise.Promise.<T>)>} arr An array of |
744 | * promises to wait on. |
745 | * @return {!webdriver.promise.Promise.<!Array.<T>>} A promise that is |
746 | * fulfilled with an array containing the fulfilled values of the |
747 | * input array, or rejected with the same reason as the first |
748 | * rejected value. |
749 | * @template T |
750 | */ |
751 | webdriver.promise.all = function(arr) { |
752 | var n = arr.length; |
753 | if (!n) { |
754 | return webdriver.promise.fulfilled([]); |
755 | } |
756 | |
757 | var toFulfill = n; |
758 | var result = webdriver.promise.defer(); |
759 | var values = []; |
760 | |
761 | var onFulfill = function(index, value) { |
762 | values[index] = value; |
763 | toFulfill--; |
764 | if (toFulfill == 0) { |
765 | result.fulfill(values); |
766 | } |
767 | }; |
768 | |
769 | for (var i = 0; i < n; ++i) { |
770 | webdriver.promise.asap( |
771 | arr[i], goog.partial(onFulfill, i), result.reject); |
772 | } |
773 | |
774 | return result.promise; |
775 | }; |
776 | |
777 | |
778 | /** |
779 | * Calls a function for each element in an array and inserts the result into a |
780 | * new array, which is used as the fulfillment value of the promise returned |
781 | * by this function. |
782 | * |
783 | * <p>If the return value of the mapping function is a promise, this function |
784 | * will wait for it to be fulfilled before inserting it into the new array. |
785 | * |
786 | * <p>If the mapping function throws or returns a rejected promise, the |
787 | * promise returned by this function will be rejected with the same reason. |
788 | * Only the first failure will be reported; all subsequent errors will be |
789 | * silently ignored. |
790 | * |
791 | * @param {!(Array.<TYPE>|webdriver.promise.Promise.<!Array.<TYPE>>)} arr The |
792 | * array to iterator over, or a promise that will resolve to said array. |
793 | * @param {function(this: SELF, TYPE, number, !Array.<TYPE>): ?} fn The |
794 | * function to call for each element in the array. This function should |
795 | * expect three arguments (the element, the index, and the array itself. |
796 | * @param {SELF=} opt_self The object to be used as the value of 'this' within |
797 | * {@code fn}. |
798 | * @template TYPE, SELF |
799 | */ |
800 | webdriver.promise.map = function(arr, fn, opt_self) { |
801 | return webdriver.promise.when(arr, function(arr) { |
802 | var result = goog.array.map(arr, fn, opt_self); |
803 | return webdriver.promise.all(result); |
804 | }); |
805 | }; |
806 | |
807 | |
808 | /** |
809 | * Calls a function for each element in an array, and if the function returns |
810 | * true adds the element to a new array. |
811 | * |
812 | * <p>If the return value of the filter function is a promise, this function |
813 | * will wait for it to be fulfilled before determining whether to insert the |
814 | * element into the new array. |
815 | * |
816 | * <p>If the filter function throws or returns a rejected promise, the promise |
817 | * returned by this function will be rejected with the same reason. Only the |
818 | * first failure will be reported; all subsequent errors will be silently |
819 | * ignored. |
820 | * |
821 | * @param {!(Array.<TYPE>|webdriver.promise.Promise.<!Array.<TYPE>>)} arr The |
822 | * array to iterator over, or a promise that will resolve to said array. |
823 | * @param {function(this: SELF, TYPE, number, !Array.<TYPE>): ( |
824 | * boolean|webdriver.promise.Promise.<boolean>)} fn The function |
825 | * to call for each element in the array. |
826 | * @param {SELF=} opt_self The object to be used as the value of 'this' within |
827 | * {@code fn}. |
828 | * @template TYPE, SELF |
829 | */ |
830 | webdriver.promise.filter = function(arr, fn, opt_self) { |
831 | return webdriver.promise.when(arr, function(arr) { |
832 | var originalValues = goog.array.clone(arr); |
833 | return webdriver.promise.map(arr, fn, opt_self).then(function(include) { |
834 | return goog.array.filter(originalValues, function(value, index) { |
835 | return include[index]; |
836 | }); |
837 | }); |
838 | }); |
839 | }; |
840 | |
841 | |
842 | /** |
843 | * Returns a promise that will be resolved with the input value in a |
844 | * fully-resolved state. If the value is an array, each element will be fully |
845 | * resolved. Likewise, if the value is an object, all keys will be fully |
846 | * resolved. In both cases, all nested arrays and objects will also be |
847 | * fully resolved. All fields are resolved in place; the returned promise will |
848 | * resolve on {@code value} and not a copy. |
849 | * |
850 | * Warning: This function makes no checks against objects that contain |
851 | * cyclical references: |
852 | * <pre><code> |
853 | * var value = {}; |
854 | * value['self'] = value; |
855 | * webdriver.promise.fullyResolved(value); // Stack overflow. |
856 | * </code></pre> |
857 | * |
858 | * @param {*} value The value to fully resolve. |
859 | * @return {!webdriver.promise.Promise} A promise for a fully resolved version |
860 | * of the input value. |
861 | */ |
862 | webdriver.promise.fullyResolved = function(value) { |
863 | if (webdriver.promise.isPromise(value)) { |
864 | return webdriver.promise.when(value, webdriver.promise.fullyResolveValue_); |
865 | } |
866 | return webdriver.promise.fullyResolveValue_(value); |
867 | }; |
868 | |
869 | |
870 | /** |
871 | * @param {*} value The value to fully resolve. If a promise, assumed to |
872 | * already be resolved. |
873 | * @return {!webdriver.promise.Promise} A promise for a fully resolved version |
874 | * of the input value. |
875 | * @private |
876 | */ |
877 | webdriver.promise.fullyResolveValue_ = function(value) { |
878 | switch (goog.typeOf(value)) { |
879 | case 'array': |
880 | return webdriver.promise.fullyResolveKeys_( |
881 | /** @type {!Array} */ (value)); |
882 | |
883 | case 'object': |
884 | if (webdriver.promise.isPromise(value)) { |
885 | // We get here when the original input value is a promise that |
886 | // resolves to itself. When the user provides us with such a promise, |
887 | // trust that it counts as a "fully resolved" value and return it. |
888 | // Of course, since it's already a promise, we can just return it |
889 | // to the user instead of wrapping it in another promise. |
890 | return /** @type {!webdriver.promise.Promise} */ (value); |
891 | } |
892 | |
893 | if (goog.isNumber(value.nodeType) && |
894 | goog.isObject(value.ownerDocument) && |
895 | goog.isNumber(value.ownerDocument.nodeType)) { |
896 | // DOM node; return early to avoid infinite recursion. Should we |
897 | // only support objects with a certain level of nesting? |
898 | return webdriver.promise.fulfilled(value); |
899 | } |
900 | |
901 | return webdriver.promise.fullyResolveKeys_( |
902 | /** @type {!Object} */ (value)); |
903 | |
904 | default: // boolean, function, null, number, string, undefined |
905 | return webdriver.promise.fulfilled(value); |
906 | } |
907 | }; |
908 | |
909 | |
910 | /** |
911 | * @param {!(Array|Object)} obj the object to resolve. |
912 | * @return {!webdriver.promise.Promise} A promise that will be resolved with the |
913 | * input object once all of its values have been fully resolved. |
914 | * @private |
915 | */ |
916 | webdriver.promise.fullyResolveKeys_ = function(obj) { |
917 | var isArray = goog.isArray(obj); |
918 | var numKeys = isArray ? obj.length : goog.object.getCount(obj); |
919 | if (!numKeys) { |
920 | return webdriver.promise.fulfilled(obj); |
921 | } |
922 | |
923 | var numResolved = 0; |
924 | var deferred = new webdriver.promise.Deferred(); |
925 | |
926 | // In pre-IE9, goog.array.forEach will not iterate properly over arrays |
927 | // containing undefined values because "index in array" returns false |
928 | // when array[index] === undefined (even for x = [undefined, 1]). To get |
929 | // around this, we need to use our own forEach implementation. |
930 | // DO NOT REMOVE THIS UNTIL WE NO LONGER SUPPORT IE8. This cannot be |
931 | // reproduced in IE9 by changing the browser/document modes, it requires an |
932 | // actual pre-IE9 browser. Yay, IE! |
933 | var forEachKey = !isArray ? goog.object.forEach : function(arr, fn) { |
934 | var n = arr.length; |
935 | for (var i = 0; i < n; ++i) { |
936 | fn.call(null, arr[i], i, arr); |
937 | } |
938 | }; |
939 | |
940 | forEachKey(obj, function(partialValue, key) { |
941 | var type = goog.typeOf(partialValue); |
942 | if (type != 'array' && type != 'object') { |
943 | maybeResolveValue(); |
944 | return; |
945 | } |
946 | |
947 | webdriver.promise.fullyResolved(partialValue).then( |
948 | function(resolvedValue) { |
949 | obj[key] = resolvedValue; |
950 | maybeResolveValue(); |
951 | }, |
952 | deferred.reject); |
953 | }); |
954 | |
955 | return deferred.promise; |
956 | |
957 | function maybeResolveValue() { |
958 | if (++numResolved == numKeys) { |
959 | deferred.fulfill(obj); |
960 | } |
961 | } |
962 | }; |
963 | |
964 | |
965 | ////////////////////////////////////////////////////////////////////////////// |
966 | // |
967 | // webdriver.promise.ControlFlow |
968 | // |
969 | ////////////////////////////////////////////////////////////////////////////// |
970 | |
971 | |
972 | |
973 | /** |
974 | * Handles the execution of scheduled tasks, each of which may be an |
975 | * asynchronous operation. The control flow will ensure tasks are executed in |
976 | * the ordered scheduled, starting each task only once those before it have |
977 | * completed. |
978 | * |
979 | * <p>Each task scheduled within this flow may return a |
980 | * {@link webdriver.promise.Promise} to indicate it is an asynchronous |
981 | * operation. The ControlFlow will wait for such promises to be resolved before |
982 | * marking the task as completed. |
983 | * |
984 | * <p>Tasks and each callback registered on a {@link webdriver.promise.Deferred} |
985 | * will be run in their own ControlFlow frame. Any tasks scheduled within a |
986 | * frame will have priority over previously scheduled tasks. Furthermore, if |
987 | * any of the tasks in the frame fails, the remainder of the tasks in that frame |
988 | * will be discarded and the failure will be propagated to the user through the |
989 | * callback/task's promised result. |
990 | * |
991 | * <p>Each time a ControlFlow empties its task queue, it will fire an |
992 | * {@link webdriver.promise.ControlFlow.EventType.IDLE} event. Conversely, |
993 | * whenever the flow terminates due to an unhandled error, it will remove all |
994 | * remaining tasks in its queue and fire an |
995 | * {@link webdriver.promise.ControlFlow.EventType.UNCAUGHT_EXCEPTION} event. If |
996 | * there are no listeners registered with the flow, the error will be |
997 | * rethrown to the global error handler. |
998 | * |
999 | * @param {webdriver.promise.ControlFlow.Timer=} opt_timer The timer object |
1000 | * to use. Should only be set for testing. |
1001 | * @constructor |
1002 | * @extends {webdriver.EventEmitter} |
1003 | */ |
1004 | webdriver.promise.ControlFlow = function(opt_timer) { |
1005 | webdriver.EventEmitter.call(this); |
1006 | |
1007 | /** |
1008 | * The timer used by this instance. |
1009 | * @type {webdriver.promise.ControlFlow.Timer} |
1010 | */ |
1011 | this.timer = opt_timer || webdriver.promise.ControlFlow.defaultTimer; |
1012 | |
1013 | /** |
1014 | * A list of recent tasks. Each time a new task is started, or a frame is |
1015 | * completed, the previously recorded task is removed from this list. If |
1016 | * there are multiple tasks, task N+1 is considered a sub-task of task |
1017 | * N. |
1018 | * @private {!Array.<!webdriver.promise.Task_>} |
1019 | */ |
1020 | this.history_ = []; |
1021 | }; |
1022 | goog.inherits(webdriver.promise.ControlFlow, webdriver.EventEmitter); |
1023 | |
1024 | |
1025 | /** |
1026 | * @typedef {{clearInterval: function(number), |
1027 | * clearTimeout: function(number), |
1028 | * setInterval: function(!Function, number): number, |
1029 | * setTimeout: function(!Function, number): number}} |
1030 | */ |
1031 | webdriver.promise.ControlFlow.Timer; |
1032 | |
1033 | |
1034 | /** |
1035 | * The default timer object, which uses the global timer functions. |
1036 | * @type {webdriver.promise.ControlFlow.Timer} |
1037 | */ |
1038 | webdriver.promise.ControlFlow.defaultTimer = (function() { |
1039 | // The default timer functions may be defined as free variables for the |
1040 | // current context, so do not reference them using "window" or |
1041 | // "goog.global". Also, we must invoke them in a closure, and not using |
1042 | // bind(), so we do not get "TypeError: Illegal invocation" (WebKit) or |
1043 | // "Invalid calling object" (IE) errors. |
1044 | return { |
1045 | clearInterval: wrap(clearInterval), |
1046 | clearTimeout: wrap(clearTimeout), |
1047 | setInterval: wrap(setInterval), |
1048 | setTimeout: wrap(setTimeout) |
1049 | }; |
1050 | |
1051 | function wrap(fn) { |
1052 | return function() { |
1053 | // Cannot use .call() or .apply() since we do not know which variable |
1054 | // the function is bound to, and using the wrong one will generate |
1055 | // an error. |
1056 | return fn(arguments[0], arguments[1]); |
1057 | }; |
1058 | } |
1059 | })(); |
1060 | |
1061 | |
1062 | /** |
1063 | * Events that may be emitted by an {@link webdriver.promise.ControlFlow}. |
1064 | * @enum {string} |
1065 | */ |
1066 | webdriver.promise.ControlFlow.EventType = { |
1067 | |
1068 | /** Emitted when all tasks have been successfully executed. */ |
1069 | IDLE: 'idle', |
1070 | |
1071 | /** Emitted whenever a new task has been scheduled. */ |
1072 | SCHEDULE_TASK: 'scheduleTask', |
1073 | |
1074 | /** |
1075 | * Emitted whenever a control flow aborts due to an unhandled promise |
1076 | * rejection. This event will be emitted along with the offending rejection |
1077 | * reason. Upon emitting this event, the control flow will empty its task |
1078 | * queue and revert to its initial state. |
1079 | */ |
1080 | UNCAUGHT_EXCEPTION: 'uncaughtException' |
1081 | }; |
1082 | |
1083 | |
1084 | /** |
1085 | * How often, in milliseconds, the event loop should run. |
1086 | * @type {number} |
1087 | * @const |
1088 | */ |
1089 | webdriver.promise.ControlFlow.EVENT_LOOP_FREQUENCY = 10; |
1090 | |
1091 | |
1092 | /** |
1093 | * Tracks the active execution frame for this instance. Lazily initialized |
1094 | * when the first task is scheduled. |
1095 | * @private {webdriver.promise.Frame_} |
1096 | */ |
1097 | webdriver.promise.ControlFlow.prototype.activeFrame_ = null; |
1098 | |
1099 | |
1100 | /** |
1101 | * A reference to the frame in which new tasks should be scheduled. If |
1102 | * {@code null}, tasks will be scheduled within the active frame. When forcing |
1103 | * a function to run in the context of a new frame, this pointer is used to |
1104 | * ensure tasks are scheduled within the newly created frame, even though it |
1105 | * won't be active yet. |
1106 | * @private {webdriver.promise.Frame_} |
1107 | * @see {#runInNewFrame_} |
1108 | */ |
1109 | webdriver.promise.ControlFlow.prototype.schedulingFrame_ = null; |
1110 | |
1111 | |
1112 | /** |
1113 | * Timeout ID set when the flow is about to shutdown without any errors |
1114 | * being detected. Upon shutting down, the flow will emit an |
1115 | * {@link webdriver.promise.ControlFlow.EventType.IDLE} event. Idle events |
1116 | * always follow a brief timeout in order to catch latent errors from the last |
1117 | * completed task. If this task had a callback registered, but no errback, and |
1118 | * the task fails, the unhandled failure would not be reported by the promise |
1119 | * system until the next turn of the event loop: |
1120 | * |
1121 | * // Schedule 1 task that fails. |
1122 | * var result = webriver.promise.controlFlow().schedule('example', |
1123 | * function() { return webdriver.promise.rejected('failed'); }); |
1124 | * // Set a callback on the result. This delays reporting the unhandled |
1125 | * // failure for 1 turn of the event loop. |
1126 | * result.then(goog.nullFunction); |
1127 | * |
1128 | * @private {?number} |
1129 | */ |
1130 | webdriver.promise.ControlFlow.prototype.shutdownId_ = null; |
1131 | |
1132 | |
1133 | /** |
1134 | * Interval ID for this instance's event loop. |
1135 | * @private {?number} |
1136 | */ |
1137 | webdriver.promise.ControlFlow.prototype.eventLoopId_ = null; |
1138 | |
1139 | |
1140 | /** |
1141 | * The number of "pending" promise rejections. |
1142 | * |
1143 | * <p>Each time a promise is rejected and is not handled by a listener, it will |
1144 | * schedule a 0-based timeout to check if it is still unrejected in the next |
1145 | * turn of the JS-event loop. This allows listeners to attach to, and handle, |
1146 | * the rejected promise at any point in same turn of the event loop that the |
1147 | * promise was rejected. |
1148 | * |
1149 | * <p>When this flow's own event loop triggers, it will not run if there |
1150 | * are any outstanding promise rejections. This allows unhandled promises to |
1151 | * be reported before a new task is started, ensuring the error is reported to |
1152 | * the current task queue. |
1153 | * |
1154 | * @private {number} |
1155 | */ |
1156 | webdriver.promise.ControlFlow.prototype.pendingRejections_ = 0; |
1157 | |
1158 | |
1159 | /** |
1160 | * The number of aborted frames since the last time a task was executed or a |
1161 | * frame completed successfully. |
1162 | * @private {number} |
1163 | */ |
1164 | webdriver.promise.ControlFlow.prototype.numAbortedFrames_ = 0; |
1165 | |
1166 | |
1167 | /** |
1168 | * Resets this instance, clearing its queue and removing all event listeners. |
1169 | */ |
1170 | webdriver.promise.ControlFlow.prototype.reset = function() { |
1171 | this.activeFrame_ = null; |
1172 | this.clearHistory(); |
1173 | this.removeAllListeners(); |
1174 | this.cancelShutdown_(); |
1175 | this.cancelEventLoop_(); |
1176 | }; |
1177 | |
1178 | |
1179 | /** |
1180 | * Returns a summary of the recent task activity for this instance. This |
1181 | * includes the most recently completed task, as well as any parent tasks. In |
1182 | * the returned summary, the task at index N is considered a sub-task of the |
1183 | * task at index N+1. |
1184 | * @return {!Array.<string>} A summary of this instance's recent task |
1185 | * activity. |
1186 | */ |
1187 | webdriver.promise.ControlFlow.prototype.getHistory = function() { |
1188 | var pendingTasks = []; |
1189 | var currentFrame = this.activeFrame_; |
1190 | while (currentFrame) { |
1191 | var task = currentFrame.getPendingTask(); |
1192 | if (task) { |
1193 | pendingTasks.push(task); |
1194 | } |
1195 | // A frame's parent node will always be another frame. |
1196 | currentFrame = |
1197 | /** @type {webdriver.promise.Frame_} */ (currentFrame.getParent()); |
1198 | } |
1199 | |
1200 | var fullHistory = goog.array.concat(this.history_, pendingTasks); |
1201 | return goog.array.map(fullHistory, function(task) { |
1202 | return task.toString(); |
1203 | }); |
1204 | }; |
1205 | |
1206 | |
1207 | /** Clears this instance's task history. */ |
1208 | webdriver.promise.ControlFlow.prototype.clearHistory = function() { |
1209 | this.history_ = []; |
1210 | }; |
1211 | |
1212 | |
1213 | /** |
1214 | * Removes a completed task from this instance's history record. If any |
1215 | * tasks remain from aborted frames, those will be removed as well. |
1216 | * @private |
1217 | */ |
1218 | webdriver.promise.ControlFlow.prototype.trimHistory_ = function() { |
1219 | if (this.numAbortedFrames_) { |
1220 | goog.array.splice(this.history_, |
1221 | this.history_.length - this.numAbortedFrames_, |
1222 | this.numAbortedFrames_); |
1223 | this.numAbortedFrames_ = 0; |
1224 | } |
1225 | this.history_.pop(); |
1226 | }; |
1227 | |
1228 | |
1229 | /** |
1230 | * Property used to track whether an error has been annotated by |
1231 | * {@link webdriver.promise.ControlFlow#annotateError}. |
1232 | * @private {string} |
1233 | * @const |
1234 | */ |
1235 | webdriver.promise.ControlFlow.ANNOTATION_PROPERTY_ = |
1236 | 'webdriver_promise_error_'; |
1237 | |
1238 | |
1239 | /** |
1240 | * Appends a summary of this instance's recent task history to the given |
1241 | * error's stack trace. This function will also ensure the error's stack trace |
1242 | * is in canonical form. |
1243 | * @param {!(Error|goog.testing.JsUnitException)} e The error to annotate. |
1244 | * @return {!(Error|goog.testing.JsUnitException)} The annotated error. |
1245 | */ |
1246 | webdriver.promise.ControlFlow.prototype.annotateError = function(e) { |
1247 | if (!!e[webdriver.promise.ControlFlow.ANNOTATION_PROPERTY_]) { |
1248 | return e; |
1249 | } |
1250 | |
1251 | var history = this.getHistory(); |
1252 | if (history.length) { |
1253 | e = webdriver.stacktrace.format(e); |
1254 | |
1255 | /** @type {!Error} */(e).stack += [ |
1256 | '\n==== async task ====\n', |
1257 | history.join('\n==== async task ====\n') |
1258 | ].join(''); |
1259 | |
1260 | e[webdriver.promise.ControlFlow.ANNOTATION_PROPERTY_] = true; |
1261 | } |
1262 | |
1263 | return e; |
1264 | }; |
1265 | |
1266 | |
1267 | /** |
1268 | * @return {string} The scheduled tasks still pending with this instance. |
1269 | */ |
1270 | webdriver.promise.ControlFlow.prototype.getSchedule = function() { |
1271 | return this.activeFrame_ ? this.activeFrame_.getRoot().toString() : '[]'; |
1272 | }; |
1273 | |
1274 | |
1275 | /** |
1276 | * Schedules a task for execution. If there is nothing currently in the |
1277 | * queue, the task will be executed in the next turn of the event loop. |
1278 | * |
1279 | * @param {!Function} fn The function to call to start the task. If the |
1280 | * function returns a {@link webdriver.promise.Promise}, this instance |
1281 | * will wait for it to be resolved before starting the next task. |
1282 | * @param {string=} opt_description A description of the task. |
1283 | * @return {!webdriver.promise.Promise} A promise that will be resolved with |
1284 | * the result of the action. |
1285 | */ |
1286 | webdriver.promise.ControlFlow.prototype.execute = function( |
1287 | fn, opt_description) { |
1288 | this.cancelShutdown_(); |
1289 | |
1290 | if (!this.activeFrame_) { |
1291 | this.activeFrame_ = new webdriver.promise.Frame_(this); |
1292 | } |
1293 | |
1294 | // Trim an extra frame off the generated stack trace for the call to this |
1295 | // function. |
1296 | var snapshot = new webdriver.stacktrace.Snapshot(1); |
1297 | var task = new webdriver.promise.Task_( |
1298 | this, fn, opt_description || '', snapshot); |
1299 | var scheduleIn = this.schedulingFrame_ || this.activeFrame_; |
1300 | scheduleIn.addChild(task); |
1301 | |
1302 | this.emit(webdriver.promise.ControlFlow.EventType.SCHEDULE_TASK); |
1303 | |
1304 | this.scheduleEventLoopStart_(); |
1305 | return task.promise; |
1306 | }; |
1307 | |
1308 | |
1309 | /** |
1310 | * Inserts a {@code setTimeout} into the command queue. This is equivalent to |
1311 | * a thread sleep in a synchronous programming language. |
1312 | * |
1313 | * @param {number} ms The timeout delay, in milliseconds. |
1314 | * @param {string=} opt_description A description to accompany the timeout. |
1315 | * @return {!webdriver.promise.Promise} A promise that will be resolved with |
1316 | * the result of the action. |
1317 | */ |
1318 | webdriver.promise.ControlFlow.prototype.timeout = function( |
1319 | ms, opt_description) { |
1320 | return this.execute(function() { |
1321 | return webdriver.promise.delayed(ms); |
1322 | }, opt_description); |
1323 | }; |
1324 | |
1325 | |
1326 | /** |
1327 | * Schedules a task that shall wait for a condition to hold. Each condition |
1328 | * function may return any value, but it will always be evaluated as a boolean. |
1329 | * |
1330 | * <p>Condition functions may schedule sub-tasks with this instance, however, |
1331 | * their execution time will be factored into whether a wait has timed out. |
1332 | * |
1333 | * <p>In the event a condition returns a Promise, the polling loop will wait for |
1334 | * it to be resolved before evaluating whether the condition has been satisfied. |
1335 | * The resolution time for a promise is factored into whether a wait has timed |
1336 | * out. |
1337 | * |
1338 | * <p>If the condition function throws, or returns a rejected promise, the |
1339 | * wait task will fail. |
1340 | * |
1341 | * @param {!Function} condition The condition function to poll. |
1342 | * @param {number} timeout How long to wait, in milliseconds, for the condition |
1343 | * to hold before timing out. |
1344 | * @param {string=} opt_message An optional error message to include if the |
1345 | * wait times out; defaults to the empty string. |
1346 | * @return {!webdriver.promise.Promise} A promise that will be resolved when the |
1347 | * condition has been satisified. The promise shall be rejected if the wait |
1348 | * times out waiting for the condition. |
1349 | */ |
1350 | webdriver.promise.ControlFlow.prototype.wait = function( |
1351 | condition, timeout, opt_message) { |
1352 | var sleep = Math.min(timeout, 100); |
1353 | var self = this; |
1354 | |
1355 | return this.execute(function() { |
1356 | var startTime = goog.now(); |
1357 | var waitResult = new webdriver.promise.Deferred(); |
1358 | var waitFrame = self.activeFrame_; |
1359 | waitFrame.isWaiting = true; |
1360 | pollCondition(); |
1361 | return waitResult.promise; |
1362 | |
1363 | function pollCondition() { |
1364 | self.runInNewFrame_(condition, function(value) { |
1365 | var elapsed = goog.now() - startTime; |
1366 | if (!!value) { |
1367 | waitFrame.isWaiting = false; |
1368 | waitResult.fulfill(value); |
1369 | } else if (elapsed >= timeout) { |
1370 | waitResult.reject(new Error((opt_message ? opt_message + '\n' : '') + |
1371 | 'Wait timed out after ' + elapsed + 'ms')); |
1372 | } else { |
1373 | self.timer.setTimeout(pollCondition, sleep); |
1374 | } |
1375 | }, waitResult.reject, true); |
1376 | } |
1377 | }, opt_message); |
1378 | }; |
1379 | |
1380 | |
1381 | /** |
1382 | * Schedules a task that will wait for another promise to resolve. The resolved |
1383 | * promise's value will be returned as the task result. |
1384 | * @param {!webdriver.promise.Promise} promise The promise to wait on. |
1385 | * @return {!webdriver.promise.Promise} A promise that will resolve when the |
1386 | * task has completed. |
1387 | */ |
1388 | webdriver.promise.ControlFlow.prototype.await = function(promise) { |
1389 | return this.execute(function() { |
1390 | return promise; |
1391 | }); |
1392 | }; |
1393 | |
1394 | |
1395 | /** |
1396 | * Schedules the interval for this instance's event loop, if necessary. |
1397 | * @private |
1398 | */ |
1399 | webdriver.promise.ControlFlow.prototype.scheduleEventLoopStart_ = function() { |
1400 | if (!this.eventLoopId_) { |
1401 | this.eventLoopId_ = this.timer.setInterval( |
1402 | goog.bind(this.runEventLoop_, this), |
1403 | webdriver.promise.ControlFlow.EVENT_LOOP_FREQUENCY); |
1404 | } |
1405 | }; |
1406 | |
1407 | |
1408 | /** |
1409 | * Cancels the event loop, if necessary. |
1410 | * @private |
1411 | */ |
1412 | webdriver.promise.ControlFlow.prototype.cancelEventLoop_ = function() { |
1413 | if (this.eventLoopId_) { |
1414 | this.timer.clearInterval(this.eventLoopId_); |
1415 | this.eventLoopId_ = null; |
1416 | } |
1417 | }; |
1418 | |
1419 | |
1420 | /** |
1421 | * Executes the next task for the current frame. If the current frame has no |
1422 | * more tasks, the frame's result will be resolved, returning control to the |
1423 | * frame's creator. This will terminate the flow if the completed frame was at |
1424 | * the top of the stack. |
1425 | * @private |
1426 | */ |
1427 | webdriver.promise.ControlFlow.prototype.runEventLoop_ = function() { |
1428 | // If we get here and there are pending promise rejections, then those |
1429 | // promises are queued up to run as soon as this (JS) event loop terminates. |
1430 | // Short-circuit our loop to give those promises a chance to run. Otherwise, |
1431 | // we might start a new task only to have it fail because of one of these |
1432 | // pending rejections. |
1433 | if (this.pendingRejections_) { |
1434 | return; |
1435 | } |
1436 | |
1437 | // If the flow aborts due to an unhandled exception after we've scheduled |
1438 | // another turn of the execution loop, we can end up in here with no tasks |
1439 | // left. This is OK, just quietly return. |
1440 | if (!this.activeFrame_) { |
1441 | this.commenceShutdown_(); |
1442 | return; |
1443 | } |
1444 | |
1445 | var task; |
1446 | if (this.activeFrame_.getPendingTask() || !(task = this.getNextTask_())) { |
1447 | // Either the current frame is blocked on a pending task, or we don't have |
1448 | // a task to finish because we've completed a frame. When completing a |
1449 | // frame, we must abort the event loop to allow the frame's promise's |
1450 | // callbacks to execute. |
1451 | return; |
1452 | } |
1453 | |
1454 | var activeFrame = this.activeFrame_; |
1455 | activeFrame.setPendingTask(task); |
1456 | var markTaskComplete = goog.bind(function() { |
1457 | this.history_.push(/** @type {!webdriver.promise.Task_} */ (task)); |
1458 | activeFrame.setPendingTask(null); |
1459 | }, this); |
1460 | |
1461 | this.trimHistory_(); |
1462 | var self = this; |
1463 | this.runInNewFrame_(task.execute, function(result) { |
1464 | markTaskComplete(); |
1465 | task.fulfill(result); |
1466 | }, function(error) { |
1467 | markTaskComplete(); |
1468 | |
1469 | if (!webdriver.promise.isError_(error) && |
1470 | !webdriver.promise.isPromise(error)) { |
1471 | error = Error(error); |
1472 | } |
1473 | |
1474 | task.reject(self.annotateError(/** @type {!Error} */ (error))); |
1475 | }, true); |
1476 | }; |
1477 | |
1478 | |
1479 | /** |
1480 | * @return {webdriver.promise.Task_} The next task to execute, or |
1481 | * {@code null} if a frame was resolved. |
1482 | * @private |
1483 | */ |
1484 | webdriver.promise.ControlFlow.prototype.getNextTask_ = function() { |
1485 | var firstChild = this.activeFrame_.getFirstChild(); |
1486 | if (!firstChild) { |
1487 | if (!this.activeFrame_.isWaiting) { |
1488 | this.resolveFrame_(this.activeFrame_); |
1489 | } |
1490 | return null; |
1491 | } |
1492 | |
1493 | if (firstChild instanceof webdriver.promise.Frame_) { |
1494 | this.activeFrame_ = firstChild; |
1495 | return this.getNextTask_(); |
1496 | } |
1497 | |
1498 | firstChild.getParent().removeChild(firstChild); |
1499 | return firstChild; |
1500 | }; |
1501 | |
1502 | |
1503 | /** |
1504 | * @param {!webdriver.promise.Frame_} frame The frame to resolve. |
1505 | * @private |
1506 | */ |
1507 | webdriver.promise.ControlFlow.prototype.resolveFrame_ = function(frame) { |
1508 | if (this.activeFrame_ === frame) { |
1509 | // Frame parent is always another frame, but the compiler is not smart |
1510 | // enough to recognize this. |
1511 | this.activeFrame_ = |
1512 | /** @type {webdriver.promise.Frame_} */ (frame.getParent()); |
1513 | } |
1514 | |
1515 | if (frame.getParent()) { |
1516 | frame.getParent().removeChild(frame); |
1517 | } |
1518 | this.trimHistory_(); |
1519 | frame.fulfill(); |
1520 | |
1521 | if (!this.activeFrame_) { |
1522 | this.commenceShutdown_(); |
1523 | } |
1524 | }; |
1525 | |
1526 | |
1527 | /** |
1528 | * Aborts the current frame. The frame, and all of the tasks scheduled within it |
1529 | * will be discarded. If this instance does not have an active frame, it will |
1530 | * immediately terminate all execution. |
1531 | * @param {*} error The reason the frame is being aborted; typically either |
1532 | * an Error or string. |
1533 | * @private |
1534 | */ |
1535 | webdriver.promise.ControlFlow.prototype.abortFrame_ = function(error) { |
1536 | // Annotate the error value if it is Error-like. |
1537 | if (webdriver.promise.isError_(error)) { |
1538 | this.annotateError(/** @type {!Error} */ (error)); |
1539 | } |
1540 | this.numAbortedFrames_++; |
1541 | |
1542 | if (!this.activeFrame_) { |
1543 | this.abortNow_(error); |
1544 | return; |
1545 | } |
1546 | |
1547 | // Frame parent is always another frame, but the compiler is not smart |
1548 | // enough to recognize this. |
1549 | var parent = /** @type {webdriver.promise.Frame_} */ ( |
1550 | this.activeFrame_.getParent()); |
1551 | if (parent) { |
1552 | parent.removeChild(this.activeFrame_); |
1553 | } |
1554 | |
1555 | var frame = this.activeFrame_; |
1556 | this.activeFrame_ = parent; |
1557 | frame.reject(error); |
1558 | }; |
1559 | |
1560 | |
1561 | /** |
1562 | * Executes a function in a new frame. If the function does not schedule any new |
1563 | * tasks, the frame will be discarded and the function's result returned |
1564 | * immediately. Otherwise, a promise will be returned. This promise will be |
1565 | * resolved with the function's result once all of the tasks scheduled within |
1566 | * the function have been completed. If the function's frame is aborted, the |
1567 | * returned promise will be rejected. |
1568 | * |
1569 | * @param {!Function} fn The function to execute. |
1570 | * @param {function(*)} callback The function to call with a successful result. |
1571 | * @param {function(*)} errback The function to call if there is an error. |
1572 | * @param {boolean=} opt_activate Whether the active frame should be updated to |
1573 | * the newly created frame so tasks are treated as sub-tasks. |
1574 | * @private |
1575 | */ |
1576 | webdriver.promise.ControlFlow.prototype.runInNewFrame_ = function( |
1577 | fn, callback, errback, opt_activate) { |
1578 | var newFrame = new webdriver.promise.Frame_(this), |
1579 | self = this, |
1580 | oldFrame = this.activeFrame_; |
1581 | |
1582 | try { |
1583 | if (!this.activeFrame_) { |
1584 | this.activeFrame_ = newFrame; |
1585 | } else { |
1586 | this.activeFrame_.addChild(newFrame); |
1587 | } |
1588 | |
1589 | // Activate the new frame to force tasks to be treated as sub-tasks of |
1590 | // the parent frame. |
1591 | if (opt_activate) { |
1592 | this.activeFrame_ = newFrame; |
1593 | } |
1594 | |
1595 | try { |
1596 | this.schedulingFrame_ = newFrame; |
1597 | webdriver.promise.pushFlow_(this); |
1598 | var result = fn(); |
1599 | } finally { |
1600 | webdriver.promise.popFlow_(); |
1601 | this.schedulingFrame_ = null; |
1602 | } |
1603 | newFrame.lockFrame(); |
1604 | |
1605 | // If there was nothing scheduled in the new frame we can discard the |
1606 | // frame and return immediately. |
1607 | if (!newFrame.children_.length) { |
1608 | removeNewFrame(); |
1609 | webdriver.promise.asap(result, callback, errback); |
1610 | return; |
1611 | } |
1612 | |
1613 | newFrame.then(function() { |
1614 | webdriver.promise.asap(result, callback, errback); |
1615 | }, function(e) { |
1616 | if (result instanceof webdriver.promise.Promise && result.isPending()) { |
1617 | result.cancel(e); |
1618 | e = result; |
1619 | } |
1620 | errback(e); |
1621 | }); |
1622 | } catch (ex) { |
1623 | removeNewFrame(new webdriver.promise.CanceledTaskError_(ex)); |
1624 | errback(ex); |
1625 | } |
1626 | |
1627 | /** |
1628 | * @param {webdriver.promise.CanceledTaskError_=} opt_err If provided, the |
1629 | * error that triggered the removal of this frame. |
1630 | */ |
1631 | function removeNewFrame(opt_err) { |
1632 | var parent = newFrame.getParent(); |
1633 | if (parent) { |
1634 | parent.removeChild(newFrame); |
1635 | } |
1636 | |
1637 | if (opt_err) { |
1638 | newFrame.cancelRemainingTasks(opt_err); |
1639 | } |
1640 | self.activeFrame_ = oldFrame; |
1641 | } |
1642 | }; |
1643 | |
1644 | |
1645 | /** |
1646 | * Commences the shutdown sequence for this instance. After one turn of the |
1647 | * event loop, this object will emit the |
1648 | * {@link webdriver.promise.ControlFlow.EventType.IDLE} event to signal |
1649 | * listeners that it has completed. During this wait, if another task is |
1650 | * scheduled, the shutdown will be aborted. |
1651 | * @private |
1652 | */ |
1653 | webdriver.promise.ControlFlow.prototype.commenceShutdown_ = function() { |
1654 | if (!this.shutdownId_) { |
1655 | // Go ahead and stop the event loop now. If we're in here, then there are |
1656 | // no more frames with tasks to execute. If we waited to cancel the event |
1657 | // loop in our timeout below, the event loop could trigger *before* the |
1658 | // timeout, generating an error from there being no frames. |
1659 | // If #execute is called before the timeout below fires, it will cancel |
1660 | // the timeout and restart the event loop. |
1661 | this.cancelEventLoop_(); |
1662 | |
1663 | var self = this; |
1664 | self.shutdownId_ = self.timer.setTimeout(function() { |
1665 | self.shutdownId_ = null; |
1666 | self.emit(webdriver.promise.ControlFlow.EventType.IDLE); |
1667 | }, 0); |
1668 | } |
1669 | }; |
1670 | |
1671 | |
1672 | /** |
1673 | * Cancels the shutdown sequence if it is currently scheduled. |
1674 | * @private |
1675 | */ |
1676 | webdriver.promise.ControlFlow.prototype.cancelShutdown_ = function() { |
1677 | if (this.shutdownId_) { |
1678 | this.timer.clearTimeout(this.shutdownId_); |
1679 | this.shutdownId_ = null; |
1680 | } |
1681 | }; |
1682 | |
1683 | |
1684 | /** |
1685 | * Aborts this flow, abandoning all remaining tasks. If there are |
1686 | * listeners registered, an {@code UNCAUGHT_EXCEPTION} will be emitted with the |
1687 | * offending {@code error}, otherwise, the {@code error} will be rethrown to the |
1688 | * global error handler. |
1689 | * @param {*} error Object describing the error that caused the flow to |
1690 | * abort; usually either an Error or string value. |
1691 | * @private |
1692 | */ |
1693 | webdriver.promise.ControlFlow.prototype.abortNow_ = function(error) { |
1694 | this.activeFrame_ = null; |
1695 | this.cancelShutdown_(); |
1696 | this.cancelEventLoop_(); |
1697 | |
1698 | var listeners = this.listeners( |
1699 | webdriver.promise.ControlFlow.EventType.UNCAUGHT_EXCEPTION); |
1700 | if (!listeners.length) { |
1701 | this.timer.setTimeout(function() { |
1702 | throw error; |
1703 | }, 0); |
1704 | } else { |
1705 | this.emit(webdriver.promise.ControlFlow.EventType.UNCAUGHT_EXCEPTION, |
1706 | error); |
1707 | } |
1708 | }; |
1709 | |
1710 | |
1711 | |
1712 | /** |
1713 | * A single node in an {@link webdriver.promise.ControlFlow}'s task tree. |
1714 | * @param {!webdriver.promise.ControlFlow} flow The flow this instance belongs |
1715 | * to. |
1716 | * @constructor |
1717 | * @extends {webdriver.promise.Deferred} |
1718 | * @private |
1719 | */ |
1720 | webdriver.promise.Node_ = function(flow) { |
1721 | webdriver.promise.Deferred.call(this, null, flow); |
1722 | }; |
1723 | goog.inherits(webdriver.promise.Node_, webdriver.promise.Deferred); |
1724 | |
1725 | |
1726 | /** |
1727 | * This node's parent. |
1728 | * @private {webdriver.promise.Node_} |
1729 | */ |
1730 | webdriver.promise.Node_.prototype.parent_ = null; |
1731 | |
1732 | |
1733 | /** @return {webdriver.promise.Node_} This node's parent. */ |
1734 | webdriver.promise.Node_.prototype.getParent = function() { |
1735 | return this.parent_; |
1736 | }; |
1737 | |
1738 | |
1739 | /** |
1740 | * @param {webdriver.promise.Node_} parent This node's new parent. |
1741 | */ |
1742 | webdriver.promise.Node_.prototype.setParent = function(parent) { |
1743 | this.parent_ = parent; |
1744 | }; |
1745 | |
1746 | |
1747 | /** |
1748 | * @return {!webdriver.promise.Node_} The root of this node's tree. |
1749 | */ |
1750 | webdriver.promise.Node_.prototype.getRoot = function() { |
1751 | var root = this; |
1752 | while (root.parent_) { |
1753 | root = root.parent_; |
1754 | } |
1755 | return root; |
1756 | }; |
1757 | |
1758 | |
1759 | |
1760 | /** |
1761 | * An execution frame within a {@link webdriver.promise.ControlFlow}. Each |
1762 | * frame represents the execution context for either a |
1763 | * {@link webdriver.promise.Task_} or a callback on a |
1764 | * {@link webdriver.promise.Deferred}. |
1765 | * |
1766 | * <p>Each frame may contain sub-frames. If child N is a sub-frame, then the |
1767 | * items queued within it are given priority over child N+1. |
1768 | * |
1769 | * @param {!webdriver.promise.ControlFlow} flow The flow this instance belongs |
1770 | * to. |
1771 | * @constructor |
1772 | * @extends {webdriver.promise.Node_} |
1773 | * @private |
1774 | */ |
1775 | webdriver.promise.Frame_ = function(flow) { |
1776 | webdriver.promise.Node_.call(this, flow); |
1777 | |
1778 | var reject = goog.bind(this.reject, this); |
1779 | var cancelRemainingTasks = goog.bind(this.cancelRemainingTasks, this); |
1780 | |
1781 | /** @override */ |
1782 | this.reject = function(e) { |
1783 | cancelRemainingTasks(new webdriver.promise.CanceledTaskError_(e)); |
1784 | reject(e); |
1785 | }; |
1786 | |
1787 | /** |
1788 | * @private {!Array.<!(webdriver.promise.Frame_|webdriver.promise.Task_)>} |
1789 | */ |
1790 | this.children_ = []; |
1791 | }; |
1792 | goog.inherits(webdriver.promise.Frame_, webdriver.promise.Node_); |
1793 | |
1794 | |
1795 | /** |
1796 | * The task currently being executed within this frame. |
1797 | * @private {webdriver.promise.Task_} |
1798 | */ |
1799 | webdriver.promise.Frame_.prototype.pendingTask_ = null; |
1800 | |
1801 | |
1802 | /** |
1803 | * Whether this frame is active. A frame is considered active once one of its |
1804 | * descendants has been removed for execution. |
1805 | * |
1806 | * Adding a sub-frame as a child to an active frame is an indication that |
1807 | * a callback to a {@link webdriver.promise.Deferred} is being invoked and any |
1808 | * tasks scheduled within it should have priority over previously scheduled |
1809 | * tasks: |
1810 | * <code><pre> |
1811 | * var flow = webdriver.promise.controlFlow(); |
1812 | * flow.execute('start here', goog.nullFunction).then(function() { |
1813 | * flow.execute('this should execute 2nd', goog.nullFunction); |
1814 | * }); |
1815 | * flow.execute('this should execute last', goog.nullFunction); |
1816 | * </pre></code> |
1817 | * |
1818 | * @private {boolean} |
1819 | */ |
1820 | webdriver.promise.Frame_.prototype.isActive_ = false; |
1821 | |
1822 | |
1823 | /** |
1824 | * Whether this frame is currently locked. A locked frame represents a callback |
1825 | * or task function which has run to completion and scheduled all of its tasks. |
1826 | * |
1827 | * <p>Once a frame becomes {@link #isActive_ active}, any new frames which are |
1828 | * added represent callbacks on a {@link webdriver.promise.Deferred}, whose |
1829 | * tasks must be given priority over previously scheduled tasks. |
1830 | * |
1831 | * @private {boolean} |
1832 | */ |
1833 | webdriver.promise.Frame_.prototype.isLocked_ = false; |
1834 | |
1835 | |
1836 | /** |
1837 | * A reference to the last node inserted in this frame. |
1838 | * @private {webdriver.promise.Node_} |
1839 | */ |
1840 | webdriver.promise.Frame_.prototype.lastInsertedChild_ = null; |
1841 | |
1842 | |
1843 | /** |
1844 | * Marks all of the tasks that are descendants of this frame in the execution |
1845 | * tree as cancelled. This is necessary for callbacks scheduled asynchronous. |
1846 | * For example: |
1847 | * |
1848 | * var someResult; |
1849 | * webdriver.promise.createFlow(function(flow) { |
1850 | * someResult = flow.execute(function() {}); |
1851 | * throw Error(); |
1852 | * }).addErrback(function(err) { |
1853 | * console.log('flow failed: ' + err); |
1854 | * someResult.then(function() { |
1855 | * console.log('task succeeded!'); |
1856 | * }, function(err) { |
1857 | * console.log('task failed! ' + err); |
1858 | * }); |
1859 | * }); |
1860 | * // flow failed: Error: boom |
1861 | * // task failed! CanceledTaskError: Task discarded due to a previous |
1862 | * // task failure: Error: boom |
1863 | * |
1864 | * @param {!webdriver.promise.CanceledTaskError_} error The cancellation |
1865 | * error. |
1866 | */ |
1867 | webdriver.promise.Frame_.prototype.cancelRemainingTasks = function(error) { |
1868 | goog.array.forEach(this.children_, function(child) { |
1869 | if (child instanceof webdriver.promise.Frame_) { |
1870 | child.cancelRemainingTasks(error); |
1871 | } else { |
1872 | // None of the previously registered listeners should be notified that |
1873 | // the task is being canceled, however, we need at least one errback |
1874 | // to prevent the cancellation from bubbling up. |
1875 | child.removeAll(); |
1876 | child.thenCatch(goog.nullFunction); |
1877 | child.cancel(error); |
1878 | } |
1879 | }); |
1880 | }; |
1881 | |
1882 | |
1883 | /** |
1884 | * @return {webdriver.promise.Task_} The task currently executing |
1885 | * within this frame, if any. |
1886 | */ |
1887 | webdriver.promise.Frame_.prototype.getPendingTask = function() { |
1888 | return this.pendingTask_; |
1889 | }; |
1890 | |
1891 | |
1892 | /** |
1893 | * @param {webdriver.promise.Task_} task The task currently |
1894 | * executing within this frame, if any. |
1895 | */ |
1896 | webdriver.promise.Frame_.prototype.setPendingTask = function(task) { |
1897 | this.pendingTask_ = task; |
1898 | }; |
1899 | |
1900 | |
1901 | /** Locks this frame. */ |
1902 | webdriver.promise.Frame_.prototype.lockFrame = function() { |
1903 | this.isLocked_ = true; |
1904 | }; |
1905 | |
1906 | |
1907 | /** |
1908 | * Adds a new node to this frame. |
1909 | * @param {!(webdriver.promise.Frame_|webdriver.promise.Task_)} node |
1910 | * The node to insert. |
1911 | */ |
1912 | webdriver.promise.Frame_.prototype.addChild = function(node) { |
1913 | if (this.lastInsertedChild_ && |
1914 | this.lastInsertedChild_ instanceof webdriver.promise.Frame_ && |
1915 | !this.lastInsertedChild_.isLocked_) { |
1916 | this.lastInsertedChild_.addChild(node); |
1917 | return; |
1918 | } |
1919 | |
1920 | node.setParent(this); |
1921 | |
1922 | if (this.isActive_ && node instanceof webdriver.promise.Frame_) { |
1923 | var index = 0; |
1924 | if (this.lastInsertedChild_ instanceof |
1925 | webdriver.promise.Frame_) { |
1926 | index = goog.array.indexOf(this.children_, this.lastInsertedChild_) + 1; |
1927 | } |
1928 | goog.array.insertAt(this.children_, node, index); |
1929 | this.lastInsertedChild_ = node; |
1930 | return; |
1931 | } |
1932 | |
1933 | this.lastInsertedChild_ = node; |
1934 | this.children_.push(node); |
1935 | }; |
1936 | |
1937 | |
1938 | /** |
1939 | * @return {(webdriver.promise.Frame_|webdriver.promise.Task_)} This frame's |
1940 | * fist child. |
1941 | */ |
1942 | webdriver.promise.Frame_.prototype.getFirstChild = function() { |
1943 | this.isActive_ = true; |
1944 | this.lastInsertedChild_ = null; |
1945 | return this.children_[0]; |
1946 | }; |
1947 | |
1948 | |
1949 | /** |
1950 | * Removes a child from this frame. |
1951 | * @param {!(webdriver.promise.Frame_|webdriver.promise.Task_)} child |
1952 | * The child to remove. |
1953 | */ |
1954 | webdriver.promise.Frame_.prototype.removeChild = function(child) { |
1955 | var index = goog.array.indexOf(this.children_, child); |
1956 | child.setParent(null); |
1957 | goog.array.removeAt(this.children_, index); |
1958 | if (this.lastInsertedChild_ === child) { |
1959 | this.lastInsertedChild_ = null; |
1960 | } |
1961 | }; |
1962 | |
1963 | |
1964 | /** @override */ |
1965 | webdriver.promise.Frame_.prototype.toString = function() { |
1966 | return '[' + goog.array.map(this.children_, function(child) { |
1967 | return child.toString(); |
1968 | }).join(', ') + ']'; |
1969 | }; |
1970 | |
1971 | |
1972 | |
1973 | /** |
1974 | * A task to be executed by a {@link webdriver.promise.ControlFlow}. |
1975 | * |
1976 | * @param {!webdriver.promise.ControlFlow} flow The flow this instances belongs |
1977 | * to. |
1978 | * @param {!Function} fn The function to call when the task executes. If it |
1979 | * returns a {@code webdriver.promise.Promise}, the flow will wait |
1980 | * for it to be resolved before starting the next task. |
1981 | * @param {string} description A description of the task for debugging. |
1982 | * @param {!webdriver.stacktrace.Snapshot} snapshot A snapshot of the stack |
1983 | * when this task was scheduled. |
1984 | * @constructor |
1985 | * @extends {webdriver.promise.Node_} |
1986 | * @private |
1987 | */ |
1988 | webdriver.promise.Task_ = function(flow, fn, description, snapshot) { |
1989 | webdriver.promise.Node_.call(this, flow); |
1990 | |
1991 | /** |
1992 | * Executes this task. |
1993 | * @type {!Function} |
1994 | */ |
1995 | this.execute = fn; |
1996 | |
1997 | /** @private {string} */ |
1998 | this.description_ = description; |
1999 | |
2000 | /** @private {!webdriver.stacktrace.Snapshot} */ |
2001 | this.snapshot_ = snapshot; |
2002 | }; |
2003 | goog.inherits(webdriver.promise.Task_, webdriver.promise.Node_); |
2004 | |
2005 | |
2006 | /** @return {string} This task's description. */ |
2007 | webdriver.promise.Task_.prototype.getDescription = function() { |
2008 | return this.description_; |
2009 | }; |
2010 | |
2011 | |
2012 | /** @override */ |
2013 | webdriver.promise.Task_.prototype.toString = function() { |
2014 | var stack = this.snapshot_.getStacktrace(); |
2015 | var ret = this.description_; |
2016 | if (stack.length) { |
2017 | if (this.description_) { |
2018 | ret += '\n'; |
2019 | } |
2020 | ret += stack.join('\n'); |
2021 | } |
2022 | return ret; |
2023 | }; |
2024 | |
2025 | |
2026 | |
2027 | /** |
2028 | * Special error used to signal when a task is canceled because a previous |
2029 | * task in the same frame failed. |
2030 | * @param {*} err The error that caused the task cancellation. |
2031 | * @constructor |
2032 | * @extends {goog.debug.Error} |
2033 | * @private |
2034 | */ |
2035 | webdriver.promise.CanceledTaskError_ = function(err) { |
2036 | goog.base(this, 'Task discarded due to a previous task failure: ' + err); |
2037 | }; |
2038 | goog.inherits(webdriver.promise.CanceledTaskError_, goog.debug.Error); |
2039 | |
2040 | |
2041 | /** @override */ |
2042 | webdriver.promise.CanceledTaskError_.prototype.name = 'CanceledTaskError'; |
2043 | |
2044 | |
2045 | |
2046 | /** |
2047 | * The default flow to use if no others are active. |
2048 | * @private {!webdriver.promise.ControlFlow} |
2049 | */ |
2050 | webdriver.promise.defaultFlow_ = new webdriver.promise.ControlFlow(); |
2051 | |
2052 | |
2053 | /** |
2054 | * A stack of active control flows, with the top of the stack used to schedule |
2055 | * commands. When there are multiple flows on the stack, the flow at index N |
2056 | * represents a callback triggered within a task owned by the flow at index |
2057 | * N-1. |
2058 | * @private {!Array.<!webdriver.promise.ControlFlow>} |
2059 | */ |
2060 | webdriver.promise.activeFlows_ = []; |
2061 | |
2062 | |
2063 | /** |
2064 | * Changes the default flow to use when no others are active. |
2065 | * @param {!webdriver.promise.ControlFlow} flow The new default flow. |
2066 | * @throws {Error} If the default flow is not currently active. |
2067 | */ |
2068 | webdriver.promise.setDefaultFlow = function(flow) { |
2069 | if (webdriver.promise.activeFlows_.length) { |
2070 | throw Error('You may only change the default flow while it is active'); |
2071 | } |
2072 | webdriver.promise.defaultFlow_ = flow; |
2073 | }; |
2074 | |
2075 | |
2076 | /** |
2077 | * @return {!webdriver.promise.ControlFlow} The currently active control flow. |
2078 | */ |
2079 | webdriver.promise.controlFlow = function() { |
2080 | return /** @type {!webdriver.promise.ControlFlow} */ ( |
2081 | goog.array.peek(webdriver.promise.activeFlows_) || |
2082 | webdriver.promise.defaultFlow_); |
2083 | }; |
2084 | |
2085 | |
2086 | /** |
2087 | * @param {!webdriver.promise.ControlFlow} flow The new flow. |
2088 | * @private |
2089 | */ |
2090 | webdriver.promise.pushFlow_ = function(flow) { |
2091 | webdriver.promise.activeFlows_.push(flow); |
2092 | }; |
2093 | |
2094 | |
2095 | /** @private */ |
2096 | webdriver.promise.popFlow_ = function() { |
2097 | webdriver.promise.activeFlows_.pop(); |
2098 | }; |
2099 | |
2100 | |
2101 | /** |
2102 | * Creates a new control flow. The provided callback will be invoked as the |
2103 | * first task within the new flow, with the flow as its sole argument. Returns |
2104 | * a promise that resolves to the callback result. |
2105 | * @param {function(!webdriver.promise.ControlFlow)} callback The entry point |
2106 | * to the newly created flow. |
2107 | * @return {!webdriver.promise.Promise} A promise that resolves to the callback |
2108 | * result. |
2109 | */ |
2110 | webdriver.promise.createFlow = function(callback) { |
2111 | var flow = new webdriver.promise.ControlFlow( |
2112 | webdriver.promise.defaultFlow_.timer); |
2113 | return flow.execute(function() { |
2114 | return callback(flow); |
2115 | }); |
2116 | }; |