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 | goog.provide('webdriver.promise.Thenable'); |
55 | |
56 | goog.require('goog.array'); |
57 | goog.require('goog.debug.Error'); |
58 | goog.require('goog.object'); |
59 | goog.require('webdriver.EventEmitter'); |
60 | goog.require('webdriver.stacktrace.Snapshot'); |
61 | |
62 | |
63 | |
64 | /** |
65 | * Thenable is a promise-like object with a {@code then} method which may be |
66 | * used to schedule callbacks on a promised value. |
67 | * |
68 | * @interface |
69 | * @template T |
70 | */ |
71 | webdriver.promise.Thenable = function() {}; |
72 | |
73 | |
74 | /** |
75 | * Cancels the computation of this promise's value, rejecting the promise in the |
76 | * process. This method is a no-op if the promise has alreayd been resolved. |
77 | * |
78 | * @param {*=} opt_reason The reason this promise is being cancelled. If not an |
79 | * {@code Error}, one will be created using the value's string |
80 | * representation. |
81 | */ |
82 | webdriver.promise.Thenable.prototype.cancel = function(opt_reason) {}; |
83 | |
84 | |
85 | /** @return {boolean} Whether this promise's value is still being computed. */ |
86 | webdriver.promise.Thenable.prototype.isPending = function() {}; |
87 | |
88 | |
89 | /** |
90 | * Registers listeners for when this instance is resolved. |
91 | * |
92 | * @param {?(function(T): (R|webdriver.promise.Promise.<R>))=} opt_callback The |
93 | * function to call if this promise is successfully resolved. The function |
94 | * should expect a single argument: the promise's resolved value. |
95 | * @param {?(function(*): (R|webdriver.promise.Promise.<R>))=} opt_errback The |
96 | * function to call if this promise is rejected. The function should expect |
97 | * a single argument: the rejection reason. |
98 | * @return {!webdriver.promise.Promise.<R>} A new promise which will be |
99 | * resolved with the result of the invoked callback. |
100 | * @template R |
101 | */ |
102 | webdriver.promise.Thenable.prototype.then = function( |
103 | opt_callback, opt_errback) {}; |
104 | |
105 | |
106 | /** |
107 | * Registers a listener for when this promise is rejected. This is synonymous |
108 | * with the {@code catch} clause in a synchronous API: |
109 | * <pre><code> |
110 | * // Synchronous API: |
111 | * try { |
112 | * doSynchronousWork(); |
113 | * } catch (ex) { |
114 | * console.error(ex); |
115 | * } |
116 | * |
117 | * // Asynchronous promise API: |
118 | * doAsynchronousWork().thenCatch(function(ex) { |
119 | * console.error(ex); |
120 | * }); |
121 | * </code></pre> |
122 | * |
123 | * @param {function(*): (R|webdriver.promise.Promise.<R>)} errback The function |
124 | * to call if this promise is rejected. The function should expect a single |
125 | * argument: the rejection reason. |
126 | * @return {!webdriver.promise.Promise.<R>} A new promise which will be |
127 | * resolved with the result of the invoked callback. |
128 | * @template R |
129 | */ |
130 | webdriver.promise.Thenable.prototype.thenCatch = function(errback) {}; |
131 | |
132 | |
133 | /** |
134 | * Registers a listener to invoke when this promise is resolved, regardless |
135 | * of whether the promise's value was successfully computed. This function |
136 | * is synonymous with the {@code finally} clause in a synchronous API: |
137 | * <pre><code> |
138 | * // Synchronous API: |
139 | * try { |
140 | * doSynchronousWork(); |
141 | * } finally { |
142 | * cleanUp(); |
143 | * } |
144 | * |
145 | * // Asynchronous promise API: |
146 | * doAsynchronousWork().thenFinally(cleanUp); |
147 | * </code></pre> |
148 | * |
149 | * <b>Note:</b> similar to the {@code finally} clause, if the registered |
150 | * callback returns a rejected promise or throws an error, it will silently |
151 | * replace the rejection error (if any) from this promise: |
152 | * <pre><code> |
153 | * try { |
154 | * throw Error('one'); |
155 | * } finally { |
156 | * throw Error('two'); // Hides Error: one |
157 | * } |
158 | * |
159 | * webdriver.promise.rejected(Error('one')) |
160 | * .thenFinally(function() { |
161 | * throw Error('two'); // Hides Error: one |
162 | * }); |
163 | * </code></pre> |
164 | * |
165 | * |
166 | * @param {function(): (R|webdriver.promise.Promise.<R>)} callback The function |
167 | * to call when this promise is resolved. |
168 | * @return {!webdriver.promise.Promise.<R>} A promise that will be fulfilled |
169 | * with the callback result. |
170 | * @template R |
171 | */ |
172 | webdriver.promise.Thenable.prototype.thenFinally = function(callback) {}; |
173 | |
174 | |
175 | /** |
176 | * Property used to flag constructor's as implementing the Thenable interface |
177 | * for runtime type checking. |
178 | * @private {string} |
179 | * @const |
180 | */ |
181 | webdriver.promise.Thenable.IMPLEMENTED_BY_PROP_ = '$webdriver_Thenable'; |
182 | |
183 | |
184 | /** |
185 | * Adds a property to a class prototype to allow runtime checks of whether |
186 | * instances of that class implement the Thenable interface. This function will |
187 | * also ensure the prototype's {@code then} function is exported from compiled |
188 | * code. |
189 | * @param {function(new: webdriver.promise.Thenable, ...[?])} ctor The |
190 | * constructor whose prototype to modify. |
191 | */ |
192 | webdriver.promise.Thenable.addImplementation = function(ctor) { |
193 | // Based on goog.promise.Thenable.isImplementation. |
194 | ctor.prototype['then'] = ctor.prototype.then; |
195 | try { |
196 | // Old IE7 does not support defineProperty; IE8 only supports it for |
197 | // DOM elements. |
198 | Object.defineProperty( |
199 | ctor.prototype, |
200 | webdriver.promise.Thenable.IMPLEMENTED_BY_PROP_, |
201 | {'value': true, 'enumerable': false}); |
202 | } catch (ex) { |
203 | ctor.prototype[webdriver.promise.Thenable.IMPLEMENTED_BY_PROP_] = true; |
204 | } |
205 | }; |
206 | |
207 | |
208 | /** |
209 | * Checks if an object has been tagged for implementing the Thenable interface |
210 | * as defined by {@link webdriver.promise.Thenable.addImplementation}. |
211 | * @param {*} object The object to test. |
212 | * @return {boolean} Whether the object is an implementation of the Thenable |
213 | * interface. |
214 | */ |
215 | webdriver.promise.Thenable.isImplementation = function(object) { |
216 | // Based on goog.promise.Thenable.isImplementation. |
217 | if (!object) { |
218 | return false; |
219 | } |
220 | try { |
221 | return !!object[webdriver.promise.Thenable.IMPLEMENTED_BY_PROP_]; |
222 | } catch (e) { |
223 | return false; // Property access seems to be forbidden. |
224 | } |
225 | }; |
226 | |
227 | |
228 | |
229 | /** |
230 | * Represents the eventual value of a completed operation. Each promise may be |
231 | * in one of three states: pending, resolved, or rejected. Each promise starts |
232 | * in the pending state and may make a single transition to either a |
233 | * fulfilled or rejected state, at which point the promise is considered |
234 | * resolved. |
235 | * |
236 | * @constructor |
237 | * @implements {webdriver.promise.Thenable.<T>} |
238 | * @template T |
239 | * @see http://promises-aplus.github.io/promises-spec/ |
240 | */ |
241 | webdriver.promise.Promise = function() {}; |
242 | webdriver.promise.Thenable.addImplementation(webdriver.promise.Promise); |
243 | |
244 | |
245 | /** @override */ |
246 | webdriver.promise.Promise.prototype.cancel = function(reason) { |
247 | throw new TypeError('Unimplemented function: "cancel"'); |
248 | }; |
249 | |
250 | |
251 | /** @override */ |
252 | webdriver.promise.Promise.prototype.isPending = function() { |
253 | throw new TypeError('Unimplemented function: "isPending"'); |
254 | }; |
255 | |
256 | |
257 | /** @override */ |
258 | webdriver.promise.Promise.prototype.then = function( |
259 | opt_callback, opt_errback) { |
260 | throw new TypeError('Unimplemented function: "then"'); |
261 | }; |
262 | |
263 | |
264 | /** @override */ |
265 | webdriver.promise.Promise.prototype.thenCatch = function(errback) { |
266 | return this.then(null, errback); |
267 | }; |
268 | |
269 | |
270 | /** @override */ |
271 | webdriver.promise.Promise.prototype.thenFinally = function(callback) { |
272 | return this.then(callback, function(err) { |
273 | var value = callback(); |
274 | if (webdriver.promise.isPromise(value)) { |
275 | return value.then(function() { |
276 | throw err; |
277 | }); |
278 | } |
279 | throw err; |
280 | }); |
281 | }; |
282 | |
283 | |
284 | |
285 | /** |
286 | * Represents a value that will be resolved at some point in the future. This |
287 | * class represents the protected "producer" half of a Promise - each Deferred |
288 | * has a {@code promise} property that may be returned to consumers for |
289 | * registering callbacks, reserving the ability to resolve the deferred to the |
290 | * producer. |
291 | * |
292 | * <p>If this Deferred is rejected and there are no listeners registered before |
293 | * the next turn of the event loop, the rejection will be passed to the |
294 | * {@link webdriver.promise.ControlFlow} as an unhandled failure. |
295 | * |
296 | * <p>If this Deferred is cancelled, the cancellation reason will be forward to |
297 | * the Deferred's canceller function (if provided). The canceller may return a |
298 | * truth-y value to override the reason provided for rejection. |
299 | * |
300 | * @param {Function=} opt_canceller Function to call when cancelling the |
301 | * computation of this instance's value. |
302 | * @param {webdriver.promise.ControlFlow=} opt_flow The control flow |
303 | * this instance was created under. This should only be provided during |
304 | * unit tests. |
305 | * @constructor |
306 | * @extends {webdriver.promise.Promise.<T>} |
307 | * @template T |
308 | */ |
309 | webdriver.promise.Deferred = function(opt_canceller, opt_flow) { |
310 | /* NOTE: This class's implementation diverges from the prototypical style |
311 | * used in the rest of the atoms library. This was done intentionally to |
312 | * protect the internal Deferred state from consumers, as outlined by |
313 | * http://wiki.commonjs.org/wiki/Promises |
314 | */ |
315 | goog.base(this); |
316 | |
317 | var flow = opt_flow || webdriver.promise.controlFlow(); |
318 | |
319 | /** |
320 | * The listeners registered with this Deferred. Each element in the list will |
321 | * be a 3-tuple of the callback function, errback function, and the |
322 | * corresponding deferred object. |
323 | * @type {!Array.<!webdriver.promise.Deferred.Listener_>} |
324 | */ |
325 | var listeners = []; |
326 | |
327 | /** |
328 | * Whether this Deferred's resolution was ever handled by a listener. |
329 | * If the Deferred is rejected and its value is not handled by a listener |
330 | * before the next turn of the event loop, the error will be passed to the |
331 | * global error handler. |
332 | * @type {boolean} |
333 | */ |
334 | var handled = false; |
335 | |
336 | /** |
337 | * Key for the timeout used to delay reproting an unhandled rejection to the |
338 | * parent {@link webdriver.promise.ControlFlow}. |
339 | * @type {?number} |
340 | */ |
341 | var pendingRejectionKey = null; |
342 | |
343 | /** |
344 | * This Deferred's current state. |
345 | * @type {!webdriver.promise.Deferred.State_} |
346 | */ |
347 | var state = webdriver.promise.Deferred.State_.PENDING; |
348 | |
349 | /** |
350 | * This Deferred's resolved value; set when the state transitions from |
351 | * {@code webdriver.promise.Deferred.State_.PENDING}. |
352 | * @type {*} |
353 | */ |
354 | var value; |
355 | |
356 | /** @return {boolean} Whether this promise's value is still pending. */ |
357 | function isPending() { |
358 | return state == webdriver.promise.Deferred.State_.PENDING; |
359 | } |
360 | |
361 | /** |
362 | * Removes all of the listeners previously registered on this deferred. |
363 | * @throws {Error} If this deferred has already been resolved. |
364 | */ |
365 | function removeAll() { |
366 | listeners = []; |
367 | } |
368 | |
369 | /** |
370 | * Resolves this deferred. If the new value is a promise, this function will |
371 | * wait for it to be resolved before notifying the registered listeners. |
372 | * @param {!webdriver.promise.Deferred.State_} newState The deferred's new |
373 | * state. |
374 | * @param {*} newValue The deferred's new value. |
375 | */ |
376 | function resolve(newState, newValue) { |
377 | if (webdriver.promise.Deferred.State_.PENDING !== state) { |
378 | return; |
379 | } |
380 | |
381 | if (newValue === self) { |
382 | // See promise a+, 2.3.1 |
383 | // http://promises-aplus.github.io/promises-spec/#point-48 |
384 | throw TypeError('A promise may not resolve to itself'); |
385 | } |
386 | |
387 | state = webdriver.promise.Deferred.State_.BLOCKED; |
388 | |
389 | if (webdriver.promise.isPromise(newValue)) { |
390 | var onFulfill = goog.partial(notifyAll, newState); |
391 | var onReject = goog.partial( |
392 | notifyAll, webdriver.promise.Deferred.State_.REJECTED); |
393 | if (newValue instanceof webdriver.promise.Deferred) { |
394 | newValue.then(onFulfill, onReject); |
395 | } else { |
396 | webdriver.promise.asap(newValue, onFulfill, onReject); |
397 | } |
398 | |
399 | } else { |
400 | notifyAll(newState, newValue); |
401 | } |
402 | } |
403 | |
404 | /** |
405 | * Notifies all of the listeners registered with this Deferred that its state |
406 | * has changed. |
407 | * @param {!webdriver.promise.Deferred.State_} newState The deferred's new |
408 | * state. |
409 | * @param {*} newValue The deferred's new value. |
410 | */ |
411 | function notifyAll(newState, newValue) { |
412 | if (newState === webdriver.promise.Deferred.State_.REJECTED && |
413 | // We cannot check instanceof Error since the object may have been |
414 | // created in a different JS context. |
415 | goog.isObject(newValue) && goog.isString(newValue.message)) { |
416 | newValue = flow.annotateError(/** @type {!Error} */(newValue)); |
417 | } |
418 | |
419 | state = newState; |
420 | value = newValue; |
421 | while (listeners.length) { |
422 | notify(listeners.shift()); |
423 | } |
424 | |
425 | if (!handled && state == webdriver.promise.Deferred.State_.REJECTED) { |
426 | flow.pendingRejections_ += 1; |
427 | pendingRejectionKey = flow.timer.setTimeout(function() { |
428 | pendingRejectionKey = null; |
429 | flow.pendingRejections_ -= 1; |
430 | flow.abortFrame_(value); |
431 | }, 0); |
432 | } |
433 | } |
434 | |
435 | /** |
436 | * Notifies a single listener of this Deferred's change in state. |
437 | * @param {!webdriver.promise.Deferred.Listener_} listener The listener to |
438 | * notify. |
439 | */ |
440 | function notify(listener) { |
441 | var func = state == webdriver.promise.Deferred.State_.RESOLVED ? |
442 | listener.callback : listener.errback; |
443 | if (func) { |
444 | flow.runInNewFrame_(goog.partial(func, value), |
445 | listener.fulfill, listener.reject); |
446 | } else if (state == webdriver.promise.Deferred.State_.REJECTED) { |
447 | listener.reject(value); |
448 | } else { |
449 | listener.fulfill(value); |
450 | } |
451 | } |
452 | |
453 | /** |
454 | * The consumer promise for this instance. Provides protected access to the |
455 | * callback registering functions. |
456 | * @type {!webdriver.promise.Promise.<T>} |
457 | */ |
458 | var promise = new webdriver.promise.Promise(); |
459 | |
460 | /** |
461 | * Registers a callback on this Deferred. |
462 | * |
463 | * @param {?(function(T): (R|webdriver.promise.Promise.<R>))=} opt_callback . |
464 | * @param {?(function(*): (R|webdriver.promise.Promise.<R>))=} opt_errback . |
465 | * @return {!webdriver.promise.Promise.<R>} A new promise representing the |
466 | * result of the callback. |
467 | * @template R |
468 | * @see webdriver.promise.Promise#then |
469 | */ |
470 | function then(opt_callback, opt_errback) { |
471 | // Avoid unnecessary allocations if we weren't given any callback functions. |
472 | if (!opt_callback && !opt_errback) { |
473 | return promise; |
474 | } |
475 | |
476 | // The moment a listener is registered, we consider this deferred to be |
477 | // handled; the callback must handle any rejection errors. |
478 | handled = true; |
479 | if (pendingRejectionKey !== null) { |
480 | flow.pendingRejections_ -= 1; |
481 | flow.timer.clearTimeout(pendingRejectionKey); |
482 | pendingRejectionKey = null; |
483 | } |
484 | |
485 | var deferred = new webdriver.promise.Deferred(cancel, flow); |
486 | var listener = { |
487 | callback: opt_callback, |
488 | errback: opt_errback, |
489 | fulfill: deferred.fulfill, |
490 | reject: deferred.reject |
491 | }; |
492 | |
493 | if (state == webdriver.promise.Deferred.State_.PENDING || |
494 | state == webdriver.promise.Deferred.State_.BLOCKED) { |
495 | listeners.push(listener); |
496 | } else { |
497 | notify(listener); |
498 | } |
499 | |
500 | return deferred.promise; |
501 | } |
502 | |
503 | var self = this; |
504 | |
505 | /** |
506 | * Resolves this promise with the given value. If the value is itself a |
507 | * promise and not a reference to this deferred, this instance will wait for |
508 | * it before resolving. |
509 | * @param {T=} opt_value The fulfilled value. |
510 | */ |
511 | function fulfill(opt_value) { |
512 | resolve(webdriver.promise.Deferred.State_.RESOLVED, opt_value); |
513 | } |
514 | |
515 | /** |
516 | * Rejects this promise. If the error is itself a promise, this instance will |
517 | * be chained to it and be rejected with the error's resolved value. |
518 | * @param {*=} opt_error The rejection reason, typically either a |
519 | * {@code Error} or a {@code string}. |
520 | */ |
521 | function reject(opt_error) { |
522 | resolve(webdriver.promise.Deferred.State_.REJECTED, opt_error); |
523 | } |
524 | |
525 | /** |
526 | * Attempts to cancel the computation of this instance's value. This attempt |
527 | * will silently fail if this instance has already resolved. |
528 | * @param {*=} opt_reason The reason for cancelling this promise. |
529 | */ |
530 | function cancel(opt_reason) { |
531 | if (!isPending()) { |
532 | return; |
533 | } |
534 | |
535 | if (opt_canceller) { |
536 | opt_reason = opt_canceller(opt_reason) || opt_reason; |
537 | } |
538 | |
539 | reject(opt_reason); |
540 | } |
541 | |
542 | this.promise = promise; |
543 | this.promise.then = this.then = then; |
544 | this.promise.cancel = this.cancel = cancel; |
545 | this.promise.isPending = this.isPending = isPending; |
546 | this.fulfill = fulfill; |
547 | this.reject = this.errback = reject; |
548 | |
549 | // Only expose this function to our internal classes. |
550 | // TODO: find a cleaner way of handling this. |
551 | if (this instanceof webdriver.promise.Task_) { |
552 | this.removeAll = removeAll; |
553 | } |
554 | |
555 | // Export symbols necessary for the contract on this object to work in |
556 | // compiled mode. |
557 | goog.exportProperty(this, 'then', this.then); |
558 | goog.exportProperty(this, 'cancel', cancel); |
559 | goog.exportProperty(this, 'fulfill', fulfill); |
560 | goog.exportProperty(this, 'reject', reject); |
561 | goog.exportProperty(this, 'isPending', isPending); |
562 | goog.exportProperty(this, 'promise', this.promise); |
563 | goog.exportProperty(this.promise, 'then', this.then); |
564 | goog.exportProperty(this.promise, 'cancel', cancel); |
565 | goog.exportProperty(this.promise, 'isPending', isPending); |
566 | }; |
567 | goog.inherits(webdriver.promise.Deferred, webdriver.promise.Promise); |
568 | |
569 | |
570 | /** |
571 | * Type definition for a listener registered on a Deferred object. |
572 | * @typedef {{callback:(Function|undefined), |
573 | * errback:(Function|undefined), |
574 | * fulfill: function(*), reject: function(*)}} |
575 | * @private |
576 | */ |
577 | webdriver.promise.Deferred.Listener_; |
578 | |
579 | |
580 | /** |
581 | * The three states a {@link webdriver.promise.Deferred} object may be in. |
582 | * @enum {number} |
583 | * @private |
584 | */ |
585 | webdriver.promise.Deferred.State_ = { |
586 | REJECTED: -1, |
587 | PENDING: 0, |
588 | BLOCKED: 1, |
589 | RESOLVED: 2 |
590 | }; |
591 | |
592 | |
593 | /** |
594 | * Tests if a value is an Error-like object. This is more than an straight |
595 | * instanceof check since the value may originate from another context. |
596 | * @param {*} value The value to test. |
597 | * @return {boolean} Whether the value is an error. |
598 | * @private |
599 | */ |
600 | webdriver.promise.isError_ = function(value) { |
601 | return value instanceof Error || |
602 | goog.isObject(value) && |
603 | (Object.prototype.toString.call(value) === '[object Error]' || |
604 | // A special test for goog.testing.JsUnitException. |
605 | value.isJsUnitException); |
606 | |
607 | }; |
608 | |
609 | |
610 | /** |
611 | * Determines whether a {@code value} should be treated as a promise. |
612 | * Any object whose "then" property is a function will be considered a promise. |
613 | * |
614 | * @param {*} value The value to test. |
615 | * @return {boolean} Whether the value is a promise. |
616 | */ |
617 | webdriver.promise.isPromise = function(value) { |
618 | return !!value && goog.isObject(value) && |
619 | // Use array notation so the Closure compiler does not obfuscate away our |
620 | // contract. |
621 | goog.isFunction(value['then']); |
622 | }; |
623 | |
624 | |
625 | /** |
626 | * Creates a promise that will be resolved at a set time in the future. |
627 | * @param {number} ms The amount of time, in milliseconds, to wait before |
628 | * resolving the promise. |
629 | * @return {!webdriver.promise.Promise} The promise. |
630 | */ |
631 | webdriver.promise.delayed = function(ms) { |
632 | var timer = webdriver.promise.controlFlow().timer; |
633 | var key; |
634 | var deferred = new webdriver.promise.Deferred(function() { |
635 | timer.clearTimeout(key); |
636 | }); |
637 | key = timer.setTimeout(deferred.fulfill, ms); |
638 | return deferred.promise; |
639 | }; |
640 | |
641 | |
642 | /** |
643 | * Creates a new deferred object. |
644 | * @param {Function=} opt_canceller Function to call when cancelling the |
645 | * computation of this instance's value. |
646 | * @return {!webdriver.promise.Deferred.<T>} The new deferred object. |
647 | * @template T |
648 | */ |
649 | webdriver.promise.defer = function(opt_canceller) { |
650 | return new webdriver.promise.Deferred(opt_canceller); |
651 | }; |
652 | |
653 | |
654 | /** |
655 | * Creates a promise that has been resolved with the given value. |
656 | * @param {T=} opt_value The resolved value. |
657 | * @return {!webdriver.promise.Promise.<T>} The resolved promise. |
658 | * @template T |
659 | */ |
660 | webdriver.promise.fulfilled = function(opt_value) { |
661 | if (opt_value instanceof webdriver.promise.Promise) { |
662 | return opt_value; |
663 | } |
664 | var deferred = new webdriver.promise.Deferred(); |
665 | deferred.fulfill(opt_value); |
666 | return deferred.promise; |
667 | }; |
668 | |
669 | |
670 | /** |
671 | * Creates a promise that has been rejected with the given reason. |
672 | * @param {*=} opt_reason The rejection reason; may be any value, but is |
673 | * usually an Error or a string. |
674 | * @return {!webdriver.promise.Promise.<T>} The rejected promise. |
675 | * @template T |
676 | */ |
677 | webdriver.promise.rejected = function(opt_reason) { |
678 | var deferred = new webdriver.promise.Deferred(); |
679 | deferred.reject(opt_reason); |
680 | return deferred.promise; |
681 | }; |
682 | |
683 | |
684 | /** |
685 | * Wraps a function that is assumed to be a node-style callback as its final |
686 | * argument. This callback takes two arguments: an error value (which will be |
687 | * null if the call succeeded), and the success value as the second argument. |
688 | * If the call fails, the returned promise will be rejected, otherwise it will |
689 | * be resolved with the result. |
690 | * @param {!Function} fn The function to wrap. |
691 | * @param {...?} var_args The arguments to apply to the function, excluding the |
692 | * final callback. |
693 | * @return {!webdriver.promise.Promise} A promise that will be resolved with the |
694 | * result of the provided function's callback. |
695 | */ |
696 | webdriver.promise.checkedNodeCall = function(fn, var_args) { |
697 | var deferred = new webdriver.promise.Deferred(function() { |
698 | throw Error('This Deferred may not be cancelled'); |
699 | }); |
700 | try { |
701 | var args = goog.array.slice(arguments, 1); |
702 | args.push(function(error, value) { |
703 | error ? deferred.reject(error) : deferred.fulfill(value); |
704 | }); |
705 | fn.apply(null, args); |
706 | } catch (ex) { |
707 | deferred.reject(ex); |
708 | } |
709 | return deferred.promise; |
710 | }; |
711 | |
712 | |
713 | /** |
714 | * Registers an observer on a promised {@code value}, returning a new promise |
715 | * that will be resolved when the value is. If {@code value} is not a promise, |
716 | * then the return promise will be immediately resolved. |
717 | * @param {*} value The value to observe. |
718 | * @param {Function=} opt_callback The function to call when the value is |
719 | * resolved successfully. |
720 | * @param {Function=} opt_errback The function to call when the value is |
721 | * rejected. |
722 | * @return {!webdriver.promise.Promise} A new promise. |
723 | */ |
724 | webdriver.promise.when = function(value, opt_callback, opt_errback) { |
725 | if (webdriver.promise.Thenable.isImplementation(value)) { |
726 | return value.then(opt_callback, opt_errback); |
727 | } |
728 | |
729 | var deferred = new webdriver.promise.Deferred(); |
730 | |
731 | webdriver.promise.asap(value, deferred.fulfill, deferred.reject); |
732 | |
733 | return deferred.then(opt_callback, opt_errback); |
734 | }; |
735 | |
736 | |
737 | /** |
738 | * Invokes the appropriate callback function as soon as a promised |
739 | * {@code value} is resolved. This function is similar to |
740 | * {@link webdriver.promise.when}, except it does not return a new promise. |
741 | * @param {*} value The value to observe. |
742 | * @param {Function} callback The function to call when the value is |
743 | * resolved successfully. |
744 | * @param {Function=} opt_errback The function to call when the value is |
745 | * rejected. |
746 | */ |
747 | webdriver.promise.asap = function(value, callback, opt_errback) { |
748 | if (webdriver.promise.isPromise(value)) { |
749 | value.then(callback, opt_errback); |
750 | |
751 | // Maybe a Dojo-like deferred object? |
752 | } else if (!!value && goog.isObject(value) && |
753 | goog.isFunction(value.addCallbacks)) { |
754 | value.addCallbacks(callback, opt_errback); |
755 | |
756 | // A raw value, return a resolved promise. |
757 | } else if (callback) { |
758 | callback(value); |
759 | } |
760 | }; |
761 | |
762 | |
763 | /** |
764 | * Given an array of promises, will return a promise that will be fulfilled |
765 | * with the fulfillment values of the input array's values. If any of the |
766 | * input array's promises are rejected, the returned promise will be rejected |
767 | * with the same reason. |
768 | * |
769 | * @param {!Array.<(T|!webdriver.promise.Promise.<T>)>} arr An array of |
770 | * promises to wait on. |
771 | * @return {!webdriver.promise.Promise.<!Array.<T>>} A promise that is |
772 | * fulfilled with an array containing the fulfilled values of the |
773 | * input array, or rejected with the same reason as the first |
774 | * rejected value. |
775 | * @template T |
776 | */ |
777 | webdriver.promise.all = function(arr) { |
778 | var n = arr.length; |
779 | if (!n) { |
780 | return webdriver.promise.fulfilled([]); |
781 | } |
782 | |
783 | var toFulfill = n; |
784 | var result = webdriver.promise.defer(); |
785 | var values = []; |
786 | |
787 | var onFulfill = function(index, value) { |
788 | values[index] = value; |
789 | toFulfill--; |
790 | if (toFulfill == 0) { |
791 | result.fulfill(values); |
792 | } |
793 | }; |
794 | |
795 | for (var i = 0; i < n; ++i) { |
796 | webdriver.promise.asap( |
797 | arr[i], goog.partial(onFulfill, i), result.reject); |
798 | } |
799 | |
800 | return result.promise; |
801 | }; |
802 | |
803 | |
804 | /** |
805 | * Calls a function for each element in an array and inserts the result into a |
806 | * new array, which is used as the fulfillment value of the promise returned |
807 | * by this function. |
808 | * |
809 | * <p>If the return value of the mapping function is a promise, this function |
810 | * will wait for it to be fulfilled before inserting it into the new array. |
811 | * |
812 | * <p>If the mapping function throws or returns a rejected promise, the |
813 | * promise returned by this function will be rejected with the same reason. |
814 | * Only the first failure will be reported; all subsequent errors will be |
815 | * silently ignored. |
816 | * |
817 | * @param {!(Array.<TYPE>|webdriver.promise.Promise.<!Array.<TYPE>>)} arr The |
818 | * array to iterator over, or a promise that will resolve to said array. |
819 | * @param {function(this: SELF, TYPE, number, !Array.<TYPE>): ?} fn The |
820 | * function to call for each element in the array. This function should |
821 | * expect three arguments (the element, the index, and the array itself. |
822 | * @param {SELF=} opt_self The object to be used as the value of 'this' within |
823 | * {@code fn}. |
824 | * @template TYPE, SELF |
825 | */ |
826 | webdriver.promise.map = function(arr, fn, opt_self) { |
827 | return webdriver.promise.when(arr, function(arr) { |
828 | var result = goog.array.map(arr, fn, opt_self); |
829 | return webdriver.promise.all(result); |
830 | }); |
831 | }; |
832 | |
833 | |
834 | /** |
835 | * Calls a function for each element in an array, and if the function returns |
836 | * true adds the element to a new array. |
837 | * |
838 | * <p>If the return value of the filter function is a promise, this function |
839 | * will wait for it to be fulfilled before determining whether to insert the |
840 | * element into the new array. |
841 | * |
842 | * <p>If the filter function throws or returns a rejected promise, the promise |
843 | * returned by this function will be rejected with the same reason. Only the |
844 | * first failure will be reported; all subsequent errors will be silently |
845 | * ignored. |
846 | * |
847 | * @param {!(Array.<TYPE>|webdriver.promise.Promise.<!Array.<TYPE>>)} arr The |
848 | * array to iterator over, or a promise that will resolve to said array. |
849 | * @param {function(this: SELF, TYPE, number, !Array.<TYPE>): ( |
850 | * boolean|webdriver.promise.Promise.<boolean>)} fn The function |
851 | * to call for each element in the array. |
852 | * @param {SELF=} opt_self The object to be used as the value of 'this' within |
853 | * {@code fn}. |
854 | * @template TYPE, SELF |
855 | */ |
856 | webdriver.promise.filter = function(arr, fn, opt_self) { |
857 | return webdriver.promise.when(arr, function(arr) { |
858 | var originalValues = goog.array.clone(arr); |
859 | return webdriver.promise.map(arr, fn, opt_self).then(function(include) { |
860 | return goog.array.filter(originalValues, function(value, index) { |
861 | return include[index]; |
862 | }); |
863 | }); |
864 | }); |
865 | }; |
866 | |
867 | |
868 | /** |
869 | * Returns a promise that will be resolved with the input value in a |
870 | * fully-resolved state. If the value is an array, each element will be fully |
871 | * resolved. Likewise, if the value is an object, all keys will be fully |
872 | * resolved. In both cases, all nested arrays and objects will also be |
873 | * fully resolved. All fields are resolved in place; the returned promise will |
874 | * resolve on {@code value} and not a copy. |
875 | * |
876 | * Warning: This function makes no checks against objects that contain |
877 | * cyclical references: |
878 | * <pre><code> |
879 | * var value = {}; |
880 | * value['self'] = value; |
881 | * webdriver.promise.fullyResolved(value); // Stack overflow. |
882 | * </code></pre> |
883 | * |
884 | * @param {*} value The value to fully resolve. |
885 | * @return {!webdriver.promise.Promise} A promise for a fully resolved version |
886 | * of the input value. |
887 | */ |
888 | webdriver.promise.fullyResolved = function(value) { |
889 | if (webdriver.promise.isPromise(value)) { |
890 | return webdriver.promise.when(value, webdriver.promise.fullyResolveValue_); |
891 | } |
892 | return webdriver.promise.fullyResolveValue_(value); |
893 | }; |
894 | |
895 | |
896 | /** |
897 | * @param {*} value The value to fully resolve. If a promise, assumed to |
898 | * already be resolved. |
899 | * @return {!webdriver.promise.Promise} A promise for a fully resolved version |
900 | * of the input value. |
901 | * @private |
902 | */ |
903 | webdriver.promise.fullyResolveValue_ = function(value) { |
904 | switch (goog.typeOf(value)) { |
905 | case 'array': |
906 | return webdriver.promise.fullyResolveKeys_( |
907 | /** @type {!Array} */ (value)); |
908 | |
909 | case 'object': |
910 | if (webdriver.promise.isPromise(value)) { |
911 | // We get here when the original input value is a promise that |
912 | // resolves to itself. When the user provides us with such a promise, |
913 | // trust that it counts as a "fully resolved" value and return it. |
914 | // Of course, since it's already a promise, we can just return it |
915 | // to the user instead of wrapping it in another promise. |
916 | return /** @type {!webdriver.promise.Promise} */ (value); |
917 | } |
918 | |
919 | if (goog.isNumber(value.nodeType) && |
920 | goog.isObject(value.ownerDocument) && |
921 | goog.isNumber(value.ownerDocument.nodeType)) { |
922 | // DOM node; return early to avoid infinite recursion. Should we |
923 | // only support objects with a certain level of nesting? |
924 | return webdriver.promise.fulfilled(value); |
925 | } |
926 | |
927 | return webdriver.promise.fullyResolveKeys_( |
928 | /** @type {!Object} */ (value)); |
929 | |
930 | default: // boolean, function, null, number, string, undefined |
931 | return webdriver.promise.fulfilled(value); |
932 | } |
933 | }; |
934 | |
935 | |
936 | /** |
937 | * @param {!(Array|Object)} obj the object to resolve. |
938 | * @return {!webdriver.promise.Promise} A promise that will be resolved with the |
939 | * input object once all of its values have been fully resolved. |
940 | * @private |
941 | */ |
942 | webdriver.promise.fullyResolveKeys_ = function(obj) { |
943 | var isArray = goog.isArray(obj); |
944 | var numKeys = isArray ? obj.length : goog.object.getCount(obj); |
945 | if (!numKeys) { |
946 | return webdriver.promise.fulfilled(obj); |
947 | } |
948 | |
949 | var numResolved = 0; |
950 | var deferred = new webdriver.promise.Deferred(); |
951 | |
952 | // In pre-IE9, goog.array.forEach will not iterate properly over arrays |
953 | // containing undefined values because "index in array" returns false |
954 | // when array[index] === undefined (even for x = [undefined, 1]). To get |
955 | // around this, we need to use our own forEach implementation. |
956 | // DO NOT REMOVE THIS UNTIL WE NO LONGER SUPPORT IE8. This cannot be |
957 | // reproduced in IE9 by changing the browser/document modes, it requires an |
958 | // actual pre-IE9 browser. Yay, IE! |
959 | var forEachKey = !isArray ? goog.object.forEach : function(arr, fn) { |
960 | var n = arr.length; |
961 | for (var i = 0; i < n; ++i) { |
962 | fn.call(null, arr[i], i, arr); |
963 | } |
964 | }; |
965 | |
966 | forEachKey(obj, function(partialValue, key) { |
967 | var type = goog.typeOf(partialValue); |
968 | if (type != 'array' && type != 'object') { |
969 | maybeResolveValue(); |
970 | return; |
971 | } |
972 | |
973 | webdriver.promise.fullyResolved(partialValue).then( |
974 | function(resolvedValue) { |
975 | obj[key] = resolvedValue; |
976 | maybeResolveValue(); |
977 | }, |
978 | deferred.reject); |
979 | }); |
980 | |
981 | return deferred.promise; |
982 | |
983 | function maybeResolveValue() { |
984 | if (++numResolved == numKeys) { |
985 | deferred.fulfill(obj); |
986 | } |
987 | } |
988 | }; |
989 | |
990 | |
991 | ////////////////////////////////////////////////////////////////////////////// |
992 | // |
993 | // webdriver.promise.ControlFlow |
994 | // |
995 | ////////////////////////////////////////////////////////////////////////////// |
996 | |
997 | |
998 | |
999 | /** |
1000 | * Handles the execution of scheduled tasks, each of which may be an |
1001 | * asynchronous operation. The control flow will ensure tasks are executed in |
1002 | * the ordered scheduled, starting each task only once those before it have |
1003 | * completed. |
1004 | * |
1005 | * <p>Each task scheduled within this flow may return a |
1006 | * {@link webdriver.promise.Promise} to indicate it is an asynchronous |
1007 | * operation. The ControlFlow will wait for such promises to be resolved before |
1008 | * marking the task as completed. |
1009 | * |
1010 | * <p>Tasks and each callback registered on a {@link webdriver.promise.Deferred} |
1011 | * will be run in their own ControlFlow frame. Any tasks scheduled within a |
1012 | * frame will have priority over previously scheduled tasks. Furthermore, if |
1013 | * any of the tasks in the frame fails, the remainder of the tasks in that frame |
1014 | * will be discarded and the failure will be propagated to the user through the |
1015 | * callback/task's promised result. |
1016 | * |
1017 | * <p>Each time a ControlFlow empties its task queue, it will fire an |
1018 | * {@link webdriver.promise.ControlFlow.EventType.IDLE} event. Conversely, |
1019 | * whenever the flow terminates due to an unhandled error, it will remove all |
1020 | * remaining tasks in its queue and fire an |
1021 | * {@link webdriver.promise.ControlFlow.EventType.UNCAUGHT_EXCEPTION} event. If |
1022 | * there are no listeners registered with the flow, the error will be |
1023 | * rethrown to the global error handler. |
1024 | * |
1025 | * @param {webdriver.promise.ControlFlow.Timer=} opt_timer The timer object |
1026 | * to use. Should only be set for testing. |
1027 | * @constructor |
1028 | * @extends {webdriver.EventEmitter} |
1029 | */ |
1030 | webdriver.promise.ControlFlow = function(opt_timer) { |
1031 | webdriver.EventEmitter.call(this); |
1032 | |
1033 | /** |
1034 | * The timer used by this instance. |
1035 | * @type {webdriver.promise.ControlFlow.Timer} |
1036 | */ |
1037 | this.timer = opt_timer || webdriver.promise.ControlFlow.defaultTimer; |
1038 | |
1039 | /** |
1040 | * A list of recent tasks. Each time a new task is started, or a frame is |
1041 | * completed, the previously recorded task is removed from this list. If |
1042 | * there are multiple tasks, task N+1 is considered a sub-task of task |
1043 | * N. |
1044 | * @private {!Array.<!webdriver.promise.Task_>} |
1045 | */ |
1046 | this.history_ = []; |
1047 | }; |
1048 | goog.inherits(webdriver.promise.ControlFlow, webdriver.EventEmitter); |
1049 | |
1050 | |
1051 | /** |
1052 | * @typedef {{clearInterval: function(number), |
1053 | * clearTimeout: function(number), |
1054 | * setInterval: function(!Function, number): number, |
1055 | * setTimeout: function(!Function, number): number}} |
1056 | */ |
1057 | webdriver.promise.ControlFlow.Timer; |
1058 | |
1059 | |
1060 | /** |
1061 | * The default timer object, which uses the global timer functions. |
1062 | * @type {webdriver.promise.ControlFlow.Timer} |
1063 | */ |
1064 | webdriver.promise.ControlFlow.defaultTimer = (function() { |
1065 | // The default timer functions may be defined as free variables for the |
1066 | // current context, so do not reference them using "window" or |
1067 | // "goog.global". Also, we must invoke them in a closure, and not using |
1068 | // bind(), so we do not get "TypeError: Illegal invocation" (WebKit) or |
1069 | // "Invalid calling object" (IE) errors. |
1070 | return { |
1071 | clearInterval: wrap(clearInterval), |
1072 | clearTimeout: wrap(clearTimeout), |
1073 | setInterval: wrap(setInterval), |
1074 | setTimeout: wrap(setTimeout) |
1075 | }; |
1076 | |
1077 | function wrap(fn) { |
1078 | return function() { |
1079 | // Cannot use .call() or .apply() since we do not know which variable |
1080 | // the function is bound to, and using the wrong one will generate |
1081 | // an error. |
1082 | return fn(arguments[0], arguments[1]); |
1083 | }; |
1084 | } |
1085 | })(); |
1086 | |
1087 | |
1088 | /** |
1089 | * Events that may be emitted by an {@link webdriver.promise.ControlFlow}. |
1090 | * @enum {string} |
1091 | */ |
1092 | webdriver.promise.ControlFlow.EventType = { |
1093 | |
1094 | /** Emitted when all tasks have been successfully executed. */ |
1095 | IDLE: 'idle', |
1096 | |
1097 | /** Emitted when a ControlFlow has been reset. */ |
1098 | RESET: 'reset', |
1099 | |
1100 | /** Emitted whenever a new task has been scheduled. */ |
1101 | SCHEDULE_TASK: 'scheduleTask', |
1102 | |
1103 | /** |
1104 | * Emitted whenever a control flow aborts due to an unhandled promise |
1105 | * rejection. This event will be emitted along with the offending rejection |
1106 | * reason. Upon emitting this event, the control flow will empty its task |
1107 | * queue and revert to its initial state. |
1108 | */ |
1109 | UNCAUGHT_EXCEPTION: 'uncaughtException' |
1110 | }; |
1111 | |
1112 | |
1113 | /** |
1114 | * How often, in milliseconds, the event loop should run. |
1115 | * @type {number} |
1116 | * @const |
1117 | */ |
1118 | webdriver.promise.ControlFlow.EVENT_LOOP_FREQUENCY = 10; |
1119 | |
1120 | |
1121 | /** |
1122 | * Tracks the active execution frame for this instance. Lazily initialized |
1123 | * when the first task is scheduled. |
1124 | * @private {webdriver.promise.Frame_} |
1125 | */ |
1126 | webdriver.promise.ControlFlow.prototype.activeFrame_ = null; |
1127 | |
1128 | |
1129 | /** |
1130 | * A reference to the frame in which new tasks should be scheduled. If |
1131 | * {@code null}, tasks will be scheduled within the active frame. When forcing |
1132 | * a function to run in the context of a new frame, this pointer is used to |
1133 | * ensure tasks are scheduled within the newly created frame, even though it |
1134 | * won't be active yet. |
1135 | * @private {webdriver.promise.Frame_} |
1136 | * @see {#runInNewFrame_} |
1137 | */ |
1138 | webdriver.promise.ControlFlow.prototype.schedulingFrame_ = null; |
1139 | |
1140 | |
1141 | /** |
1142 | * Timeout ID set when the flow is about to shutdown without any errors |
1143 | * being detected. Upon shutting down, the flow will emit an |
1144 | * {@link webdriver.promise.ControlFlow.EventType.IDLE} event. Idle events |
1145 | * always follow a brief timeout in order to catch latent errors from the last |
1146 | * completed task. If this task had a callback registered, but no errback, and |
1147 | * the task fails, the unhandled failure would not be reported by the promise |
1148 | * system until the next turn of the event loop: |
1149 | * |
1150 | * // Schedule 1 task that fails. |
1151 | * var result = webriver.promise.controlFlow().schedule('example', |
1152 | * function() { return webdriver.promise.rejected('failed'); }); |
1153 | * // Set a callback on the result. This delays reporting the unhandled |
1154 | * // failure for 1 turn of the event loop. |
1155 | * result.then(goog.nullFunction); |
1156 | * |
1157 | * @private {?number} |
1158 | */ |
1159 | webdriver.promise.ControlFlow.prototype.shutdownId_ = null; |
1160 | |
1161 | |
1162 | /** |
1163 | * Interval ID for this instance's event loop. |
1164 | * @private {?number} |
1165 | */ |
1166 | webdriver.promise.ControlFlow.prototype.eventLoopId_ = null; |
1167 | |
1168 | |
1169 | /** |
1170 | * The number of "pending" promise rejections. |
1171 | * |
1172 | * <p>Each time a promise is rejected and is not handled by a listener, it will |
1173 | * schedule a 0-based timeout to check if it is still unrejected in the next |
1174 | * turn of the JS-event loop. This allows listeners to attach to, and handle, |
1175 | * the rejected promise at any point in same turn of the event loop that the |
1176 | * promise was rejected. |
1177 | * |
1178 | * <p>When this flow's own event loop triggers, it will not run if there |
1179 | * are any outstanding promise rejections. This allows unhandled promises to |
1180 | * be reported before a new task is started, ensuring the error is reported to |
1181 | * the current task queue. |
1182 | * |
1183 | * @private {number} |
1184 | */ |
1185 | webdriver.promise.ControlFlow.prototype.pendingRejections_ = 0; |
1186 | |
1187 | |
1188 | /** |
1189 | * The number of aborted frames since the last time a task was executed or a |
1190 | * frame completed successfully. |
1191 | * @private {number} |
1192 | */ |
1193 | webdriver.promise.ControlFlow.prototype.numAbortedFrames_ = 0; |
1194 | |
1195 | |
1196 | /** |
1197 | * Resets this instance, clearing its queue and removing all event listeners. |
1198 | */ |
1199 | webdriver.promise.ControlFlow.prototype.reset = function() { |
1200 | this.activeFrame_ = null; |
1201 | this.clearHistory(); |
1202 | this.emit(webdriver.promise.ControlFlow.EventType.RESET); |
1203 | this.removeAllListeners(); |
1204 | this.cancelShutdown_(); |
1205 | this.cancelEventLoop_(); |
1206 | }; |
1207 | |
1208 | |
1209 | /** |
1210 | * Returns a summary of the recent task activity for this instance. This |
1211 | * includes the most recently completed task, as well as any parent tasks. In |
1212 | * the returned summary, the task at index N is considered a sub-task of the |
1213 | * task at index N+1. |
1214 | * @return {!Array.<string>} A summary of this instance's recent task |
1215 | * activity. |
1216 | */ |
1217 | webdriver.promise.ControlFlow.prototype.getHistory = function() { |
1218 | var pendingTasks = []; |
1219 | var currentFrame = this.activeFrame_; |
1220 | while (currentFrame) { |
1221 | var task = currentFrame.getPendingTask(); |
1222 | if (task) { |
1223 | pendingTasks.push(task); |
1224 | } |
1225 | // A frame's parent node will always be another frame. |
1226 | currentFrame = |
1227 | /** @type {webdriver.promise.Frame_} */ (currentFrame.getParent()); |
1228 | } |
1229 | |
1230 | var fullHistory = goog.array.concat(this.history_, pendingTasks); |
1231 | return goog.array.map(fullHistory, function(task) { |
1232 | return task.toString(); |
1233 | }); |
1234 | }; |
1235 | |
1236 | |
1237 | /** Clears this instance's task history. */ |
1238 | webdriver.promise.ControlFlow.prototype.clearHistory = function() { |
1239 | this.history_ = []; |
1240 | }; |
1241 | |
1242 | |
1243 | /** |
1244 | * Removes a completed task from this instance's history record. If any |
1245 | * tasks remain from aborted frames, those will be removed as well. |
1246 | * @private |
1247 | */ |
1248 | webdriver.promise.ControlFlow.prototype.trimHistory_ = function() { |
1249 | if (this.numAbortedFrames_) { |
1250 | goog.array.splice(this.history_, |
1251 | this.history_.length - this.numAbortedFrames_, |
1252 | this.numAbortedFrames_); |
1253 | this.numAbortedFrames_ = 0; |
1254 | } |
1255 | this.history_.pop(); |
1256 | }; |
1257 | |
1258 | |
1259 | /** |
1260 | * Property used to track whether an error has been annotated by |
1261 | * {@link webdriver.promise.ControlFlow#annotateError}. |
1262 | * @private {string} |
1263 | * @const |
1264 | */ |
1265 | webdriver.promise.ControlFlow.ANNOTATION_PROPERTY_ = |
1266 | 'webdriver_promise_error_'; |
1267 | |
1268 | |
1269 | /** |
1270 | * Appends a summary of this instance's recent task history to the given |
1271 | * error's stack trace. This function will also ensure the error's stack trace |
1272 | * is in canonical form. |
1273 | * @param {!(Error|goog.testing.JsUnitException)} e The error to annotate. |
1274 | * @return {!(Error|goog.testing.JsUnitException)} The annotated error. |
1275 | */ |
1276 | webdriver.promise.ControlFlow.prototype.annotateError = function(e) { |
1277 | if (!!e[webdriver.promise.ControlFlow.ANNOTATION_PROPERTY_]) { |
1278 | return e; |
1279 | } |
1280 | |
1281 | var history = this.getHistory(); |
1282 | if (history.length) { |
1283 | e = webdriver.stacktrace.format(e); |
1284 | |
1285 | /** @type {!Error} */(e).stack += [ |
1286 | '\n==== async task ====\n', |
1287 | history.join('\n==== async task ====\n') |
1288 | ].join(''); |
1289 | |
1290 | e[webdriver.promise.ControlFlow.ANNOTATION_PROPERTY_] = true; |
1291 | } |
1292 | |
1293 | return e; |
1294 | }; |
1295 | |
1296 | |
1297 | /** |
1298 | * @return {string} The scheduled tasks still pending with this instance. |
1299 | */ |
1300 | webdriver.promise.ControlFlow.prototype.getSchedule = function() { |
1301 | return this.activeFrame_ ? this.activeFrame_.getRoot().toString() : '[]'; |
1302 | }; |
1303 | |
1304 | |
1305 | /** |
1306 | * Schedules a task for execution. If there is nothing currently in the |
1307 | * queue, the task will be executed in the next turn of the event loop. If |
1308 | * the task function is a generator, the task will be executed using |
1309 | * {@link webdriver.promise.consume}. |
1310 | * |
1311 | * @param {function(): (T|webdriver.promise.Promise.<T>)} fn The function to |
1312 | * call to start the task. If the function returns a |
1313 | * {@link webdriver.promise.Promise}, this instance will wait for it to be |
1314 | * resolved before starting the next task. |
1315 | * @param {string=} opt_description A description of the task. |
1316 | * @return {!webdriver.promise.Promise.<T>} A promise that will be resolved |
1317 | * with the result of the action. |
1318 | * @template T |
1319 | */ |
1320 | webdriver.promise.ControlFlow.prototype.execute = function( |
1321 | fn, opt_description) { |
1322 | if (webdriver.promise.isGenerator(fn)) { |
1323 | fn = goog.partial(webdriver.promise.consume, fn); |
1324 | } |
1325 | |
1326 | this.cancelShutdown_(); |
1327 | |
1328 | if (!this.activeFrame_) { |
1329 | this.activeFrame_ = new webdriver.promise.Frame_(this); |
1330 | } |
1331 | |
1332 | // Trim an extra frame off the generated stack trace for the call to this |
1333 | // function. |
1334 | var snapshot = new webdriver.stacktrace.Snapshot(1); |
1335 | var task = new webdriver.promise.Task_( |
1336 | this, fn, opt_description || '', snapshot); |
1337 | var scheduleIn = this.schedulingFrame_ || this.activeFrame_; |
1338 | scheduleIn.addChild(task); |
1339 | |
1340 | this.emit(webdriver.promise.ControlFlow.EventType.SCHEDULE_TASK, opt_description); |
1341 | |
1342 | this.scheduleEventLoopStart_(); |
1343 | return task.promise; |
1344 | }; |
1345 | |
1346 | |
1347 | /** |
1348 | * Inserts a {@code setTimeout} into the command queue. This is equivalent to |
1349 | * a thread sleep in a synchronous programming language. |
1350 | * |
1351 | * @param {number} ms The timeout delay, in milliseconds. |
1352 | * @param {string=} opt_description A description to accompany the timeout. |
1353 | * @return {!webdriver.promise.Promise} A promise that will be resolved with |
1354 | * the result of the action. |
1355 | */ |
1356 | webdriver.promise.ControlFlow.prototype.timeout = function( |
1357 | ms, opt_description) { |
1358 | return this.execute(function() { |
1359 | return webdriver.promise.delayed(ms); |
1360 | }, opt_description); |
1361 | }; |
1362 | |
1363 | |
1364 | /** |
1365 | * Schedules a task that shall wait for a condition to hold. Each condition |
1366 | * function may return any value, but it will always be evaluated as a boolean. |
1367 | * |
1368 | * <p>Condition functions may schedule sub-tasks with this instance, however, |
1369 | * their execution time will be factored into whether a wait has timed out. |
1370 | * |
1371 | * <p>In the event a condition returns a Promise, the polling loop will wait for |
1372 | * it to be resolved before evaluating whether the condition has been satisfied. |
1373 | * The resolution time for a promise is factored into whether a wait has timed |
1374 | * out. |
1375 | * |
1376 | * <p>If the condition function throws, or returns a rejected promise, the |
1377 | * wait task will fail. |
1378 | * |
1379 | * @param {!Function} condition The condition function to poll. |
1380 | * @param {number} timeout How long to wait, in milliseconds, for the condition |
1381 | * to hold before timing out. |
1382 | * @param {string=} opt_message An optional error message to include if the |
1383 | * wait times out; defaults to the empty string. |
1384 | * @return {!webdriver.promise.Promise} A promise that will be resolved when the |
1385 | * condition has been satisified. The promise shall be rejected if the wait |
1386 | * times out waiting for the condition. |
1387 | */ |
1388 | webdriver.promise.ControlFlow.prototype.wait = function( |
1389 | condition, timeout, opt_message) { |
1390 | var sleep = Math.min(timeout, 100); |
1391 | var self = this; |
1392 | |
1393 | if (webdriver.promise.isGenerator(condition)) { |
1394 | condition = goog.partial(webdriver.promise.consume, condition); |
1395 | } |
1396 | |
1397 | return this.execute(function() { |
1398 | var startTime = goog.now(); |
1399 | var waitResult = new webdriver.promise.Deferred(); |
1400 | var waitFrame = self.activeFrame_; |
1401 | waitFrame.isWaiting = true; |
1402 | pollCondition(); |
1403 | return waitResult.promise; |
1404 | |
1405 | function pollCondition() { |
1406 | self.runInNewFrame_(condition, function(value) { |
1407 | var elapsed = goog.now() - startTime; |
1408 | if (!!value) { |
1409 | waitFrame.isWaiting = false; |
1410 | waitResult.fulfill(value); |
1411 | } else if (elapsed >= timeout) { |
1412 | waitResult.reject(new Error((opt_message ? opt_message + '\n' : '') + |
1413 | 'Wait timed out after ' + elapsed + 'ms')); |
1414 | } else { |
1415 | self.timer.setTimeout(pollCondition, sleep); |
1416 | } |
1417 | }, waitResult.reject, true); |
1418 | } |
1419 | }, opt_message); |
1420 | }; |
1421 | |
1422 | |
1423 | /** |
1424 | * Schedules a task that will wait for another promise to resolve. The resolved |
1425 | * promise's value will be returned as the task result. |
1426 | * @param {!webdriver.promise.Promise} promise The promise to wait on. |
1427 | * @return {!webdriver.promise.Promise} A promise that will resolve when the |
1428 | * task has completed. |
1429 | */ |
1430 | webdriver.promise.ControlFlow.prototype.await = function(promise) { |
1431 | return this.execute(function() { |
1432 | return promise; |
1433 | }); |
1434 | }; |
1435 | |
1436 | |
1437 | /** |
1438 | * Schedules the interval for this instance's event loop, if necessary. |
1439 | * @private |
1440 | */ |
1441 | webdriver.promise.ControlFlow.prototype.scheduleEventLoopStart_ = function() { |
1442 | if (!this.eventLoopId_) { |
1443 | this.eventLoopId_ = this.timer.setInterval( |
1444 | goog.bind(this.runEventLoop_, this), |
1445 | webdriver.promise.ControlFlow.EVENT_LOOP_FREQUENCY); |
1446 | } |
1447 | }; |
1448 | |
1449 | |
1450 | /** |
1451 | * Cancels the event loop, if necessary. |
1452 | * @private |
1453 | */ |
1454 | webdriver.promise.ControlFlow.prototype.cancelEventLoop_ = function() { |
1455 | if (this.eventLoopId_) { |
1456 | this.timer.clearInterval(this.eventLoopId_); |
1457 | this.eventLoopId_ = null; |
1458 | } |
1459 | }; |
1460 | |
1461 | |
1462 | /** |
1463 | * Executes the next task for the current frame. If the current frame has no |
1464 | * more tasks, the frame's result will be resolved, returning control to the |
1465 | * frame's creator. This will terminate the flow if the completed frame was at |
1466 | * the top of the stack. |
1467 | * @private |
1468 | */ |
1469 | webdriver.promise.ControlFlow.prototype.runEventLoop_ = function() { |
1470 | // If we get here and there are pending promise rejections, then those |
1471 | // promises are queued up to run as soon as this (JS) event loop terminates. |
1472 | // Short-circuit our loop to give those promises a chance to run. Otherwise, |
1473 | // we might start a new task only to have it fail because of one of these |
1474 | // pending rejections. |
1475 | if (this.pendingRejections_) { |
1476 | return; |
1477 | } |
1478 | |
1479 | // If the flow aborts due to an unhandled exception after we've scheduled |
1480 | // another turn of the execution loop, we can end up in here with no tasks |
1481 | // left. This is OK, just quietly return. |
1482 | if (!this.activeFrame_) { |
1483 | this.commenceShutdown_(); |
1484 | return; |
1485 | } |
1486 | |
1487 | var task; |
1488 | if (this.activeFrame_.getPendingTask() || !(task = this.getNextTask_())) { |
1489 | // Either the current frame is blocked on a pending task, or we don't have |
1490 | // a task to finish because we've completed a frame. When completing a |
1491 | // frame, we must abort the event loop to allow the frame's promise's |
1492 | // callbacks to execute. |
1493 | return; |
1494 | } |
1495 | |
1496 | var activeFrame = this.activeFrame_; |
1497 | activeFrame.setPendingTask(task); |
1498 | var markTaskComplete = goog.bind(function() { |
1499 | this.history_.push(/** @type {!webdriver.promise.Task_} */ (task)); |
1500 | activeFrame.setPendingTask(null); |
1501 | }, this); |
1502 | |
1503 | this.trimHistory_(); |
1504 | var self = this; |
1505 | this.runInNewFrame_(task.execute, function(result) { |
1506 | markTaskComplete(); |
1507 | task.fulfill(result); |
1508 | }, function(error) { |
1509 | markTaskComplete(); |
1510 | |
1511 | if (!webdriver.promise.isError_(error) && |
1512 | !webdriver.promise.isPromise(error)) { |
1513 | error = Error(error); |
1514 | } |
1515 | |
1516 | task.reject(self.annotateError(/** @type {!Error} */ (error))); |
1517 | }, true); |
1518 | }; |
1519 | |
1520 | |
1521 | /** |
1522 | * @return {webdriver.promise.Task_} The next task to execute, or |
1523 | * {@code null} if a frame was resolved. |
1524 | * @private |
1525 | */ |
1526 | webdriver.promise.ControlFlow.prototype.getNextTask_ = function() { |
1527 | var firstChild = this.activeFrame_.getFirstChild(); |
1528 | if (!firstChild) { |
1529 | if (!this.activeFrame_.isWaiting) { |
1530 | this.resolveFrame_(this.activeFrame_); |
1531 | } |
1532 | return null; |
1533 | } |
1534 | |
1535 | if (firstChild instanceof webdriver.promise.Frame_) { |
1536 | this.activeFrame_ = firstChild; |
1537 | return this.getNextTask_(); |
1538 | } |
1539 | |
1540 | firstChild.getParent().removeChild(firstChild); |
1541 | return firstChild; |
1542 | }; |
1543 | |
1544 | |
1545 | /** |
1546 | * @param {!webdriver.promise.Frame_} frame The frame to resolve. |
1547 | * @private |
1548 | */ |
1549 | webdriver.promise.ControlFlow.prototype.resolveFrame_ = function(frame) { |
1550 | if (this.activeFrame_ === frame) { |
1551 | // Frame parent is always another frame, but the compiler is not smart |
1552 | // enough to recognize this. |
1553 | this.activeFrame_ = |
1554 | /** @type {webdriver.promise.Frame_} */ (frame.getParent()); |
1555 | } |
1556 | |
1557 | if (frame.getParent()) { |
1558 | frame.getParent().removeChild(frame); |
1559 | } |
1560 | this.trimHistory_(); |
1561 | frame.fulfill(); |
1562 | |
1563 | if (!this.activeFrame_) { |
1564 | this.commenceShutdown_(); |
1565 | } |
1566 | }; |
1567 | |
1568 | |
1569 | /** |
1570 | * Aborts the current frame. The frame, and all of the tasks scheduled within it |
1571 | * will be discarded. If this instance does not have an active frame, it will |
1572 | * immediately terminate all execution. |
1573 | * @param {*} error The reason the frame is being aborted; typically either |
1574 | * an Error or string. |
1575 | * @private |
1576 | */ |
1577 | webdriver.promise.ControlFlow.prototype.abortFrame_ = function(error) { |
1578 | // Annotate the error value if it is Error-like. |
1579 | if (webdriver.promise.isError_(error)) { |
1580 | this.annotateError(/** @type {!Error} */ (error)); |
1581 | } |
1582 | this.numAbortedFrames_++; |
1583 | |
1584 | if (!this.activeFrame_) { |
1585 | this.abortNow_(error); |
1586 | return; |
1587 | } |
1588 | |
1589 | // Frame parent is always another frame, but the compiler is not smart |
1590 | // enough to recognize this. |
1591 | var parent = /** @type {webdriver.promise.Frame_} */ ( |
1592 | this.activeFrame_.getParent()); |
1593 | if (parent) { |
1594 | parent.removeChild(this.activeFrame_); |
1595 | } |
1596 | |
1597 | var frame = this.activeFrame_; |
1598 | this.activeFrame_ = parent; |
1599 | frame.reject(error); |
1600 | }; |
1601 | |
1602 | |
1603 | /** |
1604 | * Executes a function in a new frame. If the function does not schedule any new |
1605 | * tasks, the frame will be discarded and the function's result returned |
1606 | * immediately. Otherwise, a promise will be returned. This promise will be |
1607 | * resolved with the function's result once all of the tasks scheduled within |
1608 | * the function have been completed. If the function's frame is aborted, the |
1609 | * returned promise will be rejected. |
1610 | * |
1611 | * @param {!Function} fn The function to execute. |
1612 | * @param {function(*)} callback The function to call with a successful result. |
1613 | * @param {function(*)} errback The function to call if there is an error. |
1614 | * @param {boolean=} opt_activate Whether the active frame should be updated to |
1615 | * the newly created frame so tasks are treated as sub-tasks. |
1616 | * @private |
1617 | */ |
1618 | webdriver.promise.ControlFlow.prototype.runInNewFrame_ = function( |
1619 | fn, callback, errback, opt_activate) { |
1620 | var newFrame = new webdriver.promise.Frame_(this), |
1621 | self = this, |
1622 | oldFrame = this.activeFrame_; |
1623 | |
1624 | try { |
1625 | if (!this.activeFrame_) { |
1626 | this.activeFrame_ = newFrame; |
1627 | } else { |
1628 | this.activeFrame_.addChild(newFrame); |
1629 | } |
1630 | |
1631 | // Activate the new frame to force tasks to be treated as sub-tasks of |
1632 | // the parent frame. |
1633 | if (opt_activate) { |
1634 | this.activeFrame_ = newFrame; |
1635 | } |
1636 | |
1637 | try { |
1638 | this.schedulingFrame_ = newFrame; |
1639 | webdriver.promise.pushFlow_(this); |
1640 | var result = fn(); |
1641 | } finally { |
1642 | webdriver.promise.popFlow_(); |
1643 | this.schedulingFrame_ = null; |
1644 | } |
1645 | newFrame.lockFrame(); |
1646 | |
1647 | // If there was nothing scheduled in the new frame we can discard the |
1648 | // frame and return immediately. |
1649 | if (!newFrame.children_.length) { |
1650 | removeNewFrame(); |
1651 | webdriver.promise.asap(result, callback, errback); |
1652 | return; |
1653 | } |
1654 | |
1655 | newFrame.then(function() { |
1656 | webdriver.promise.asap(result, callback, errback); |
1657 | }, function(e) { |
1658 | if (webdriver.promise.Thenable.isImplementation(result) && |
1659 | result.isPending()) { |
1660 | result.cancel(e); |
1661 | e = result; |
1662 | } |
1663 | errback(e); |
1664 | }); |
1665 | } catch (ex) { |
1666 | removeNewFrame(new webdriver.promise.CanceledTaskError_(ex)); |
1667 | errback(ex); |
1668 | } |
1669 | |
1670 | /** |
1671 | * @param {webdriver.promise.CanceledTaskError_=} opt_err If provided, the |
1672 | * error that triggered the removal of this frame. |
1673 | */ |
1674 | function removeNewFrame(opt_err) { |
1675 | var parent = newFrame.getParent(); |
1676 | if (parent) { |
1677 | parent.removeChild(newFrame); |
1678 | } |
1679 | |
1680 | if (opt_err) { |
1681 | newFrame.cancelRemainingTasks(opt_err); |
1682 | } |
1683 | self.activeFrame_ = oldFrame; |
1684 | } |
1685 | }; |
1686 | |
1687 | |
1688 | /** |
1689 | * Commences the shutdown sequence for this instance. After one turn of the |
1690 | * event loop, this object will emit the |
1691 | * {@link webdriver.promise.ControlFlow.EventType.IDLE} event to signal |
1692 | * listeners that it has completed. During this wait, if another task is |
1693 | * scheduled, the shutdown will be aborted. |
1694 | * @private |
1695 | */ |
1696 | webdriver.promise.ControlFlow.prototype.commenceShutdown_ = function() { |
1697 | if (!this.shutdownId_) { |
1698 | // Go ahead and stop the event loop now. If we're in here, then there are |
1699 | // no more frames with tasks to execute. If we waited to cancel the event |
1700 | // loop in our timeout below, the event loop could trigger *before* the |
1701 | // timeout, generating an error from there being no frames. |
1702 | // If #execute is called before the timeout below fires, it will cancel |
1703 | // the timeout and restart the event loop. |
1704 | this.cancelEventLoop_(); |
1705 | |
1706 | var self = this; |
1707 | self.shutdownId_ = self.timer.setTimeout(function() { |
1708 | self.shutdownId_ = null; |
1709 | self.emit(webdriver.promise.ControlFlow.EventType.IDLE); |
1710 | }, 0); |
1711 | } |
1712 | }; |
1713 | |
1714 | |
1715 | /** |
1716 | * Cancels the shutdown sequence if it is currently scheduled. |
1717 | * @private |
1718 | */ |
1719 | webdriver.promise.ControlFlow.prototype.cancelShutdown_ = function() { |
1720 | if (this.shutdownId_) { |
1721 | this.timer.clearTimeout(this.shutdownId_); |
1722 | this.shutdownId_ = null; |
1723 | } |
1724 | }; |
1725 | |
1726 | |
1727 | /** |
1728 | * Aborts this flow, abandoning all remaining tasks. If there are |
1729 | * listeners registered, an {@code UNCAUGHT_EXCEPTION} will be emitted with the |
1730 | * offending {@code error}, otherwise, the {@code error} will be rethrown to the |
1731 | * global error handler. |
1732 | * @param {*} error Object describing the error that caused the flow to |
1733 | * abort; usually either an Error or string value. |
1734 | * @private |
1735 | */ |
1736 | webdriver.promise.ControlFlow.prototype.abortNow_ = function(error) { |
1737 | this.activeFrame_ = null; |
1738 | this.cancelShutdown_(); |
1739 | this.cancelEventLoop_(); |
1740 | |
1741 | var listeners = this.listeners( |
1742 | webdriver.promise.ControlFlow.EventType.UNCAUGHT_EXCEPTION); |
1743 | if (!listeners.length) { |
1744 | this.timer.setTimeout(function() { |
1745 | throw error; |
1746 | }, 0); |
1747 | } else { |
1748 | this.emit(webdriver.promise.ControlFlow.EventType.UNCAUGHT_EXCEPTION, |
1749 | error); |
1750 | } |
1751 | }; |
1752 | |
1753 | |
1754 | |
1755 | /** |
1756 | * A single node in an {@link webdriver.promise.ControlFlow}'s task tree. |
1757 | * @param {!webdriver.promise.ControlFlow} flow The flow this instance belongs |
1758 | * to. |
1759 | * @constructor |
1760 | * @extends {webdriver.promise.Deferred} |
1761 | * @private |
1762 | */ |
1763 | webdriver.promise.Node_ = function(flow) { |
1764 | webdriver.promise.Deferred.call(this, null, flow); |
1765 | }; |
1766 | goog.inherits(webdriver.promise.Node_, webdriver.promise.Deferred); |
1767 | |
1768 | |
1769 | /** |
1770 | * This node's parent. |
1771 | * @private {webdriver.promise.Node_} |
1772 | */ |
1773 | webdriver.promise.Node_.prototype.parent_ = null; |
1774 | |
1775 | |
1776 | /** @return {webdriver.promise.Node_} This node's parent. */ |
1777 | webdriver.promise.Node_.prototype.getParent = function() { |
1778 | return this.parent_; |
1779 | }; |
1780 | |
1781 | |
1782 | /** |
1783 | * @param {webdriver.promise.Node_} parent This node's new parent. |
1784 | */ |
1785 | webdriver.promise.Node_.prototype.setParent = function(parent) { |
1786 | this.parent_ = parent; |
1787 | }; |
1788 | |
1789 | |
1790 | /** |
1791 | * @return {!webdriver.promise.Node_} The root of this node's tree. |
1792 | */ |
1793 | webdriver.promise.Node_.prototype.getRoot = function() { |
1794 | var root = this; |
1795 | while (root.parent_) { |
1796 | root = root.parent_; |
1797 | } |
1798 | return root; |
1799 | }; |
1800 | |
1801 | |
1802 | |
1803 | /** |
1804 | * An execution frame within a {@link webdriver.promise.ControlFlow}. Each |
1805 | * frame represents the execution context for either a |
1806 | * {@link webdriver.promise.Task_} or a callback on a |
1807 | * {@link webdriver.promise.Deferred}. |
1808 | * |
1809 | * <p>Each frame may contain sub-frames. If child N is a sub-frame, then the |
1810 | * items queued within it are given priority over child N+1. |
1811 | * |
1812 | * @param {!webdriver.promise.ControlFlow} flow The flow this instance belongs |
1813 | * to. |
1814 | * @constructor |
1815 | * @extends {webdriver.promise.Node_} |
1816 | * @private |
1817 | */ |
1818 | webdriver.promise.Frame_ = function(flow) { |
1819 | webdriver.promise.Node_.call(this, flow); |
1820 | |
1821 | var reject = goog.bind(this.reject, this); |
1822 | var cancelRemainingTasks = goog.bind(this.cancelRemainingTasks, this); |
1823 | |
1824 | /** @override */ |
1825 | this.reject = function(e) { |
1826 | cancelRemainingTasks(new webdriver.promise.CanceledTaskError_(e)); |
1827 | reject(e); |
1828 | }; |
1829 | |
1830 | /** |
1831 | * @private {!Array.<!(webdriver.promise.Frame_|webdriver.promise.Task_)>} |
1832 | */ |
1833 | this.children_ = []; |
1834 | }; |
1835 | goog.inherits(webdriver.promise.Frame_, webdriver.promise.Node_); |
1836 | |
1837 | |
1838 | /** |
1839 | * The task currently being executed within this frame. |
1840 | * @private {webdriver.promise.Task_} |
1841 | */ |
1842 | webdriver.promise.Frame_.prototype.pendingTask_ = null; |
1843 | |
1844 | |
1845 | /** |
1846 | * Whether this frame is active. A frame is considered active once one of its |
1847 | * descendants has been removed for execution. |
1848 | * |
1849 | * Adding a sub-frame as a child to an active frame is an indication that |
1850 | * a callback to a {@link webdriver.promise.Deferred} is being invoked and any |
1851 | * tasks scheduled within it should have priority over previously scheduled |
1852 | * tasks: |
1853 | * <code><pre> |
1854 | * var flow = webdriver.promise.controlFlow(); |
1855 | * flow.execute('start here', goog.nullFunction).then(function() { |
1856 | * flow.execute('this should execute 2nd', goog.nullFunction); |
1857 | * }); |
1858 | * flow.execute('this should execute last', goog.nullFunction); |
1859 | * </pre></code> |
1860 | * |
1861 | * @private {boolean} |
1862 | */ |
1863 | webdriver.promise.Frame_.prototype.isActive_ = false; |
1864 | |
1865 | |
1866 | /** |
1867 | * Whether this frame is currently locked. A locked frame represents a callback |
1868 | * or task function which has run to completion and scheduled all of its tasks. |
1869 | * |
1870 | * <p>Once a frame becomes {@link #isActive_ active}, any new frames which are |
1871 | * added represent callbacks on a {@link webdriver.promise.Deferred}, whose |
1872 | * tasks must be given priority over previously scheduled tasks. |
1873 | * |
1874 | * @private {boolean} |
1875 | */ |
1876 | webdriver.promise.Frame_.prototype.isLocked_ = false; |
1877 | |
1878 | |
1879 | /** |
1880 | * A reference to the last node inserted in this frame. |
1881 | * @private {webdriver.promise.Node_} |
1882 | */ |
1883 | webdriver.promise.Frame_.prototype.lastInsertedChild_ = null; |
1884 | |
1885 | |
1886 | /** |
1887 | * Marks all of the tasks that are descendants of this frame in the execution |
1888 | * tree as cancelled. This is necessary for callbacks scheduled asynchronous. |
1889 | * For example: |
1890 | * |
1891 | * var someResult; |
1892 | * webdriver.promise.createFlow(function(flow) { |
1893 | * someResult = flow.execute(function() {}); |
1894 | * throw Error(); |
1895 | * }).addErrback(function(err) { |
1896 | * console.log('flow failed: ' + err); |
1897 | * someResult.then(function() { |
1898 | * console.log('task succeeded!'); |
1899 | * }, function(err) { |
1900 | * console.log('task failed! ' + err); |
1901 | * }); |
1902 | * }); |
1903 | * // flow failed: Error: boom |
1904 | * // task failed! CanceledTaskError: Task discarded due to a previous |
1905 | * // task failure: Error: boom |
1906 | * |
1907 | * @param {!webdriver.promise.CanceledTaskError_} error The cancellation |
1908 | * error. |
1909 | */ |
1910 | webdriver.promise.Frame_.prototype.cancelRemainingTasks = function(error) { |
1911 | goog.array.forEach(this.children_, function(child) { |
1912 | if (child instanceof webdriver.promise.Frame_) { |
1913 | child.cancelRemainingTasks(error); |
1914 | } else { |
1915 | // None of the previously registered listeners should be notified that |
1916 | // the task is being canceled, however, we need at least one errback |
1917 | // to prevent the cancellation from bubbling up. |
1918 | child.removeAll(); |
1919 | child.thenCatch(goog.nullFunction); |
1920 | child.cancel(error); |
1921 | } |
1922 | }); |
1923 | }; |
1924 | |
1925 | |
1926 | /** |
1927 | * @return {webdriver.promise.Task_} The task currently executing |
1928 | * within this frame, if any. |
1929 | */ |
1930 | webdriver.promise.Frame_.prototype.getPendingTask = function() { |
1931 | return this.pendingTask_; |
1932 | }; |
1933 | |
1934 | |
1935 | /** |
1936 | * @param {webdriver.promise.Task_} task The task currently |
1937 | * executing within this frame, if any. |
1938 | */ |
1939 | webdriver.promise.Frame_.prototype.setPendingTask = function(task) { |
1940 | this.pendingTask_ = task; |
1941 | }; |
1942 | |
1943 | |
1944 | /** Locks this frame. */ |
1945 | webdriver.promise.Frame_.prototype.lockFrame = function() { |
1946 | this.isLocked_ = true; |
1947 | }; |
1948 | |
1949 | |
1950 | /** |
1951 | * Adds a new node to this frame. |
1952 | * @param {!(webdriver.promise.Frame_|webdriver.promise.Task_)} node |
1953 | * The node to insert. |
1954 | */ |
1955 | webdriver.promise.Frame_.prototype.addChild = function(node) { |
1956 | if (this.lastInsertedChild_ && |
1957 | this.lastInsertedChild_ instanceof webdriver.promise.Frame_ && |
1958 | !this.lastInsertedChild_.isLocked_) { |
1959 | this.lastInsertedChild_.addChild(node); |
1960 | return; |
1961 | } |
1962 | |
1963 | node.setParent(this); |
1964 | |
1965 | if (this.isActive_ && node instanceof webdriver.promise.Frame_) { |
1966 | var index = 0; |
1967 | if (this.lastInsertedChild_ instanceof |
1968 | webdriver.promise.Frame_) { |
1969 | index = goog.array.indexOf(this.children_, this.lastInsertedChild_) + 1; |
1970 | } |
1971 | goog.array.insertAt(this.children_, node, index); |
1972 | this.lastInsertedChild_ = node; |
1973 | return; |
1974 | } |
1975 | |
1976 | this.lastInsertedChild_ = node; |
1977 | this.children_.push(node); |
1978 | }; |
1979 | |
1980 | |
1981 | /** |
1982 | * @return {(webdriver.promise.Frame_|webdriver.promise.Task_)} This frame's |
1983 | * fist child. |
1984 | */ |
1985 | webdriver.promise.Frame_.prototype.getFirstChild = function() { |
1986 | this.isActive_ = true; |
1987 | this.lastInsertedChild_ = null; |
1988 | return this.children_[0]; |
1989 | }; |
1990 | |
1991 | |
1992 | /** |
1993 | * Removes a child from this frame. |
1994 | * @param {!(webdriver.promise.Frame_|webdriver.promise.Task_)} child |
1995 | * The child to remove. |
1996 | */ |
1997 | webdriver.promise.Frame_.prototype.removeChild = function(child) { |
1998 | var index = goog.array.indexOf(this.children_, child); |
1999 | child.setParent(null); |
2000 | goog.array.removeAt(this.children_, index); |
2001 | if (this.lastInsertedChild_ === child) { |
2002 | this.lastInsertedChild_ = null; |
2003 | } |
2004 | }; |
2005 | |
2006 | |
2007 | /** @override */ |
2008 | webdriver.promise.Frame_.prototype.toString = function() { |
2009 | return '[' + goog.array.map(this.children_, function(child) { |
2010 | return child.toString(); |
2011 | }).join(', ') + ']'; |
2012 | }; |
2013 | |
2014 | |
2015 | |
2016 | /** |
2017 | * A task to be executed by a {@link webdriver.promise.ControlFlow}. |
2018 | * |
2019 | * @param {!webdriver.promise.ControlFlow} flow The flow this instances belongs |
2020 | * to. |
2021 | * @param {!Function} fn The function to call when the task executes. If it |
2022 | * returns a {@code webdriver.promise.Promise}, the flow will wait |
2023 | * for it to be resolved before starting the next task. |
2024 | * @param {string} description A description of the task for debugging. |
2025 | * @param {!webdriver.stacktrace.Snapshot} snapshot A snapshot of the stack |
2026 | * when this task was scheduled. |
2027 | * @constructor |
2028 | * @extends {webdriver.promise.Node_} |
2029 | * @private |
2030 | */ |
2031 | webdriver.promise.Task_ = function(flow, fn, description, snapshot) { |
2032 | webdriver.promise.Node_.call(this, flow); |
2033 | |
2034 | /** |
2035 | * Executes this task. |
2036 | * @type {!Function} |
2037 | */ |
2038 | this.execute = fn; |
2039 | |
2040 | /** @private {string} */ |
2041 | this.description_ = description; |
2042 | |
2043 | /** @private {!webdriver.stacktrace.Snapshot} */ |
2044 | this.snapshot_ = snapshot; |
2045 | }; |
2046 | goog.inherits(webdriver.promise.Task_, webdriver.promise.Node_); |
2047 | |
2048 | |
2049 | /** @return {string} This task's description. */ |
2050 | webdriver.promise.Task_.prototype.getDescription = function() { |
2051 | return this.description_; |
2052 | }; |
2053 | |
2054 | |
2055 | /** @override */ |
2056 | webdriver.promise.Task_.prototype.toString = function() { |
2057 | var stack = this.snapshot_.getStacktrace(); |
2058 | var ret = this.description_; |
2059 | if (stack.length) { |
2060 | if (this.description_) { |
2061 | ret += '\n'; |
2062 | } |
2063 | ret += stack.join('\n'); |
2064 | } |
2065 | return ret; |
2066 | }; |
2067 | |
2068 | |
2069 | |
2070 | /** |
2071 | * Special error used to signal when a task is canceled because a previous |
2072 | * task in the same frame failed. |
2073 | * @param {*} err The error that caused the task cancellation. |
2074 | * @constructor |
2075 | * @extends {goog.debug.Error} |
2076 | * @private |
2077 | */ |
2078 | webdriver.promise.CanceledTaskError_ = function(err) { |
2079 | goog.base(this, 'Task discarded due to a previous task failure: ' + err); |
2080 | }; |
2081 | goog.inherits(webdriver.promise.CanceledTaskError_, goog.debug.Error); |
2082 | |
2083 | |
2084 | /** @override */ |
2085 | webdriver.promise.CanceledTaskError_.prototype.name = 'CanceledTaskError'; |
2086 | |
2087 | |
2088 | |
2089 | /** |
2090 | * The default flow to use if no others are active. |
2091 | * @private {!webdriver.promise.ControlFlow} |
2092 | */ |
2093 | webdriver.promise.defaultFlow_ = new webdriver.promise.ControlFlow(); |
2094 | |
2095 | |
2096 | /** |
2097 | * A stack of active control flows, with the top of the stack used to schedule |
2098 | * commands. When there are multiple flows on the stack, the flow at index N |
2099 | * represents a callback triggered within a task owned by the flow at index |
2100 | * N-1. |
2101 | * @private {!Array.<!webdriver.promise.ControlFlow>} |
2102 | */ |
2103 | webdriver.promise.activeFlows_ = []; |
2104 | |
2105 | |
2106 | /** |
2107 | * Changes the default flow to use when no others are active. |
2108 | * @param {!webdriver.promise.ControlFlow} flow The new default flow. |
2109 | * @throws {Error} If the default flow is not currently active. |
2110 | */ |
2111 | webdriver.promise.setDefaultFlow = function(flow) { |
2112 | if (webdriver.promise.activeFlows_.length) { |
2113 | throw Error('You may only change the default flow while it is active'); |
2114 | } |
2115 | webdriver.promise.defaultFlow_ = flow; |
2116 | }; |
2117 | |
2118 | |
2119 | /** |
2120 | * @return {!webdriver.promise.ControlFlow} The currently active control flow. |
2121 | */ |
2122 | webdriver.promise.controlFlow = function() { |
2123 | return /** @type {!webdriver.promise.ControlFlow} */ ( |
2124 | goog.array.peek(webdriver.promise.activeFlows_) || |
2125 | webdriver.promise.defaultFlow_); |
2126 | }; |
2127 | |
2128 | |
2129 | /** |
2130 | * @param {!webdriver.promise.ControlFlow} flow The new flow. |
2131 | * @private |
2132 | */ |
2133 | webdriver.promise.pushFlow_ = function(flow) { |
2134 | webdriver.promise.activeFlows_.push(flow); |
2135 | }; |
2136 | |
2137 | |
2138 | /** @private */ |
2139 | webdriver.promise.popFlow_ = function() { |
2140 | webdriver.promise.activeFlows_.pop(); |
2141 | }; |
2142 | |
2143 | |
2144 | /** |
2145 | * Creates a new control flow. The provided callback will be invoked as the |
2146 | * first task within the new flow, with the flow as its sole argument. Returns |
2147 | * a promise that resolves to the callback result. |
2148 | * @param {function(!webdriver.promise.ControlFlow)} callback The entry point |
2149 | * to the newly created flow. |
2150 | * @return {!webdriver.promise.Promise} A promise that resolves to the callback |
2151 | * result. |
2152 | */ |
2153 | webdriver.promise.createFlow = function(callback) { |
2154 | var flow = new webdriver.promise.ControlFlow( |
2155 | webdriver.promise.defaultFlow_.timer); |
2156 | return flow.execute(function() { |
2157 | return callback(flow); |
2158 | }); |
2159 | }; |
2160 | |
2161 | |
2162 | /** |
2163 | * Tests is a function is a generator. |
2164 | * @param {!Function} fn The function to test. |
2165 | * @return {boolean} Whether the function is a generator. |
2166 | */ |
2167 | webdriver.promise.isGenerator = function(fn) { |
2168 | return fn.constructor.name === 'GeneratorFunction'; |
2169 | }; |
2170 | |
2171 | |
2172 | /** |
2173 | * Consumes a {@code GeneratorFunction}. Each time the generator yields a |
2174 | * promise, this function will wait for it to be fulfilled before feeding the |
2175 | * fulfilled value back into {@code next}. Likewise, if a yielded promise is |
2176 | * rejected, the rejection error will be passed to {@code throw}. |
2177 | * |
2178 | * <p>Example 1: the Fibonacci Sequence. |
2179 | * <pre><code> |
2180 | * webdriver.promise.consume(function* fibonacci() { |
2181 | * var n1 = 1, n2 = 1; |
2182 | * for (var i = 0; i < 4; ++i) { |
2183 | * var tmp = yield n1 + n2; |
2184 | * n1 = n2; |
2185 | * n2 = tmp; |
2186 | * } |
2187 | * return n1 + n2; |
2188 | * }).then(function(result) { |
2189 | * console.log(result); // 13 |
2190 | * }); |
2191 | * </code></pre> |
2192 | * |
2193 | * <p>Example 2: a generator that throws. |
2194 | * <pre><code> |
2195 | * webdriver.promise.consume(function* () { |
2196 | * yield webdriver.promise.delayed(250).then(function() { |
2197 | * throw Error('boom'); |
2198 | * }); |
2199 | * }).thenCatch(function(e) { |
2200 | * console.log(e.toString()); // Error: boom |
2201 | * }); |
2202 | * </code></pre> |
2203 | * |
2204 | * @param {!Function} generatorFn The generator function to execute. |
2205 | * @param {Object=} opt_self The object to use as "this" when invoking the |
2206 | * initial generator. |
2207 | * @param {...*} var_args Any arguments to pass to the initial generator. |
2208 | * @return {!webdriver.promise.Promise.<?>} A promise that will resolve to the |
2209 | * generator's final result. |
2210 | * @throws {TypeError} If the given function is not a generator. |
2211 | */ |
2212 | webdriver.promise.consume = function(generatorFn, opt_self, var_args) { |
2213 | if (!webdriver.promise.isGenerator(generatorFn)) { |
2214 | throw TypeError('Input is not a GeneratorFunction: ' + |
2215 | generatorFn.constructor.name); |
2216 | } |
2217 | |
2218 | var deferred = webdriver.promise.defer(); |
2219 | var generator = generatorFn.apply(opt_self, goog.array.slice(arguments, 2)); |
2220 | callNext(); |
2221 | return deferred.promise; |
2222 | |
2223 | /** @param {*=} opt_value . */ |
2224 | function callNext(opt_value) { |
2225 | pump(generator.next, opt_value); |
2226 | } |
2227 | |
2228 | /** @param {*=} opt_error . */ |
2229 | function callThrow(opt_error) { |
2230 | // Dictionary lookup required because Closure compiler's built-in |
2231 | // externs does not include GeneratorFunction.prototype.throw. |
2232 | pump(generator['throw'], opt_error); |
2233 | } |
2234 | |
2235 | function pump(fn, opt_arg) { |
2236 | if (!deferred.isPending()) { |
2237 | return; // Defererd was cancelled; silently abort. |
2238 | } |
2239 | |
2240 | try { |
2241 | var result = fn.call(generator, opt_arg); |
2242 | } catch (ex) { |
2243 | deferred.reject(ex); |
2244 | return; |
2245 | } |
2246 | |
2247 | if (result.done) { |
2248 | deferred.fulfill(result.value); |
2249 | return; |
2250 | } |
2251 | |
2252 | webdriver.promise.asap(result.value, callNext, callThrow); |
2253 | } |
2254 | }; |