1345 lines
43 KiB
JavaScript
1345 lines
43 KiB
JavaScript
// Copyright 2013 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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goog.provide('goog.Promise');
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goog.require('goog.Thenable');
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goog.require('goog.asserts');
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goog.require('goog.async.FreeList');
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goog.require('goog.async.run');
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goog.require('goog.async.throwException');
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goog.require('goog.debug.Error');
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goog.require('goog.promise.Resolver');
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/**
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* NOTE: This class was created in anticipation of the built-in Promise type
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* being standardized and implemented across browsers. Now that Promise is
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* available in modern browsers, and is automatically polyfilled by the Closure
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* Compiler, by default, most new code should use native {@code Promise}
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* instead of {@code goog.Promise}. However, {@code goog.Promise} has the
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* concept of cancellation which native Promises do not yet have. So code
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* needing cancellation may still want to use {@code goog.Promise}.
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*
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* Promises provide a result that may be resolved asynchronously. A Promise may
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* be resolved by being fulfilled with a fulfillment value, rejected with a
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* rejection reason, or blocked by another Promise. A Promise is said to be
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* settled if it is either fulfilled or rejected. Once settled, the Promise
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* result is immutable.
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*
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* Promises may represent results of any type, including undefined. Rejection
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* reasons are typically Errors, but may also be of any type. Closure Promises
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* allow for optional type annotations that enforce that fulfillment values are
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* of the appropriate types at compile time.
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*
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* The result of a Promise is accessible by calling {@code then} and registering
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* {@code onFulfilled} and {@code onRejected} callbacks. Once the Promise
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* is settled, the relevant callbacks are invoked with the fulfillment value or
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* rejection reason as argument. Callbacks are always invoked in the order they
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* were registered, even when additional {@code then} calls are made from inside
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* another callback. A callback is always run asynchronously sometime after the
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* scope containing the registering {@code then} invocation has returned.
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*
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* If a Promise is resolved with another Promise, the first Promise will block
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* until the second is settled, and then assumes the same result as the second
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* Promise. This allows Promises to depend on the results of other Promises,
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* linking together multiple asynchronous operations.
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*
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* This implementation is compatible with the Promises/A+ specification and
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* passes that specification's conformance test suite. A Closure Promise may be
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* resolved with a Promise instance (or sufficiently compatible Promise-like
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* object) created by other Promise implementations. From the specification,
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* Promise-like objects are known as "Thenables".
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*
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* @see http://promisesaplus.com/
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*
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* @param {function(
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* this:RESOLVER_CONTEXT,
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* function((TYPE|IThenable<TYPE>|Thenable)=),
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* function(*=)): void} resolver
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* Initialization function that is invoked immediately with {@code resolve}
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* and {@code reject} functions as arguments. The Promise is resolved or
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* rejected with the first argument passed to either function.
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* @param {RESOLVER_CONTEXT=} opt_context An optional context for executing the
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* resolver function. If unspecified, the resolver function will be executed
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* in the default scope.
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* @constructor
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* @struct
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* @final
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* @implements {goog.Thenable<TYPE>}
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* @template TYPE,RESOLVER_CONTEXT
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*/
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goog.Promise = function(resolver, opt_context) {
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/**
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* The internal state of this Promise. Either PENDING, FULFILLED, REJECTED, or
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* BLOCKED.
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* @private {goog.Promise.State_}
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*/
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this.state_ = goog.Promise.State_.PENDING;
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/**
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* The settled result of the Promise. Immutable once set with either a
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* fulfillment value or rejection reason.
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* @private {*}
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*/
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this.result_ = undefined;
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/**
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* For Promises created by calling {@code then()}, the originating parent.
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* @private {goog.Promise}
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*/
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this.parent_ = null;
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/**
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* The linked list of {@code onFulfilled} and {@code onRejected} callbacks
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* added to this Promise by calls to {@code then()}.
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* @private {?goog.Promise.CallbackEntry_}
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*/
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this.callbackEntries_ = null;
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/**
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* The tail of the linked list of {@code onFulfilled} and {@code onRejected}
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* callbacks added to this Promise by calls to {@code then()}.
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* @private {?goog.Promise.CallbackEntry_}
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*/
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this.callbackEntriesTail_ = null;
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/**
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* Whether the Promise is in the queue of Promises to execute.
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* @private {boolean}
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*/
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this.executing_ = false;
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if (goog.Promise.UNHANDLED_REJECTION_DELAY > 0) {
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/**
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* A timeout ID used when the {@code UNHANDLED_REJECTION_DELAY} is greater
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* than 0 milliseconds. The ID is set when the Promise is rejected, and
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* cleared only if an {@code onRejected} callback is invoked for the
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* Promise (or one of its descendants) before the delay is exceeded.
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*
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* If the rejection is not handled before the timeout completes, the
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* rejection reason is passed to the unhandled rejection handler.
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* @private {number}
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*/
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this.unhandledRejectionId_ = 0;
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} else if (goog.Promise.UNHANDLED_REJECTION_DELAY == 0) {
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/**
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* When the {@code UNHANDLED_REJECTION_DELAY} is set to 0 milliseconds, a
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* boolean that is set if the Promise is rejected, and reset to false if an
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* {@code onRejected} callback is invoked for the Promise (or one of its
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* descendants). If the rejection is not handled before the next timestep,
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* the rejection reason is passed to the unhandled rejection handler.
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* @private {boolean}
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*/
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this.hadUnhandledRejection_ = false;
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}
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if (goog.Promise.LONG_STACK_TRACES) {
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/**
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* A list of stack trace frames pointing to the locations where this Promise
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* was created or had callbacks added to it. Saved to add additional context
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* to stack traces when an exception is thrown.
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* @private {!Array<string>}
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*/
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this.stack_ = [];
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this.addStackTrace_(new Error('created'));
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/**
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* Index of the most recently executed stack frame entry.
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* @private {number}
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*/
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this.currentStep_ = 0;
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}
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// As an optimization, we can skip this if resolver is goog.nullFunction.
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// This value is passed internally when creating a promise which will be
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// resolved through a more optimized path.
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if (resolver != goog.nullFunction) {
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try {
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var self = this;
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resolver.call(
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opt_context,
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function(value) {
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self.resolve_(goog.Promise.State_.FULFILLED, value);
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},
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function(reason) {
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if (goog.DEBUG &&
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!(reason instanceof goog.Promise.CancellationError)) {
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try {
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// Promise was rejected. Step up one call frame to see why.
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if (reason instanceof Error) {
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throw reason;
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} else {
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throw new Error('Promise rejected.');
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}
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} catch (e) {
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// Only thrown so browser dev tools can catch rejections of
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// promises when the option to break on caught exceptions is
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// activated.
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}
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}
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self.resolve_(goog.Promise.State_.REJECTED, reason);
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});
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} catch (e) {
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this.resolve_(goog.Promise.State_.REJECTED, e);
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}
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}
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};
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/**
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* @define {boolean} Whether traces of {@code then} calls should be included in
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* exceptions thrown
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*/
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goog.define('goog.Promise.LONG_STACK_TRACES', false);
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/**
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* @define {number} The delay in milliseconds before a rejected Promise's reason
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* is passed to the rejection handler. By default, the rejection handler
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* rethrows the rejection reason so that it appears in the developer console or
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* {@code window.onerror} handler.
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*
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* Rejections are rethrown as quickly as possible by default. A negative value
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* disables rejection handling entirely.
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*/
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goog.define('goog.Promise.UNHANDLED_REJECTION_DELAY', 0);
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/**
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* The possible internal states for a Promise. These states are not directly
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* observable to external callers.
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* @enum {number}
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* @private
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*/
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goog.Promise.State_ = {
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/** The Promise is waiting for resolution. */
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PENDING: 0,
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/** The Promise is blocked waiting for the result of another Thenable. */
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BLOCKED: 1,
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/** The Promise has been resolved with a fulfillment value. */
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FULFILLED: 2,
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/** The Promise has been resolved with a rejection reason. */
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REJECTED: 3
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};
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/**
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* Entries in the callback chain. Each call to {@code then},
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* {@code thenCatch}, or {@code thenAlways} creates an entry containing the
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* functions that may be invoked once the Promise is settled.
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*
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* @private @final @struct @constructor
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*/
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goog.Promise.CallbackEntry_ = function() {
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/** @type {?goog.Promise} */
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this.child = null;
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/** @type {Function} */
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this.onFulfilled = null;
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/** @type {Function} */
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this.onRejected = null;
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/** @type {?} */
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this.context = null;
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/** @type {?goog.Promise.CallbackEntry_} */
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this.next = null;
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/**
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* A boolean value to indicate this is a "thenAlways" callback entry.
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* Unlike a normal "then/thenVoid" a "thenAlways doesn't participate
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* in "cancel" considerations but is simply an observer and requires
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* special handling.
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* @type {boolean}
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*/
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this.always = false;
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};
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/** clear the object prior to reuse */
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goog.Promise.CallbackEntry_.prototype.reset = function() {
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this.child = null;
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this.onFulfilled = null;
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this.onRejected = null;
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this.context = null;
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this.always = false;
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};
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/**
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* @define {number} The number of currently unused objects to keep around for
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* reuse.
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*/
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goog.define('goog.Promise.DEFAULT_MAX_UNUSED', 100);
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/** @const @private {goog.async.FreeList<!goog.Promise.CallbackEntry_>} */
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goog.Promise.freelist_ = new goog.async.FreeList(
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function() { return new goog.Promise.CallbackEntry_(); },
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function(item) { item.reset(); }, goog.Promise.DEFAULT_MAX_UNUSED);
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/**
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* @param {Function} onFulfilled
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* @param {Function} onRejected
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* @param {?} context
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* @return {!goog.Promise.CallbackEntry_}
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* @private
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*/
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goog.Promise.getCallbackEntry_ = function(onFulfilled, onRejected, context) {
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var entry = goog.Promise.freelist_.get();
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entry.onFulfilled = onFulfilled;
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entry.onRejected = onRejected;
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entry.context = context;
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return entry;
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};
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/**
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* @param {!goog.Promise.CallbackEntry_} entry
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* @private
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*/
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goog.Promise.returnEntry_ = function(entry) {
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goog.Promise.freelist_.put(entry);
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};
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// NOTE: this is the same template expression as is used for
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// goog.IThenable.prototype.then
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/**
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* @param {VALUE=} opt_value
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* @return {RESULT} A new Promise that is immediately resolved
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* with the given value. If the input value is already a goog.Promise, it
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* will be returned immediately without creating a new instance.
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* @template VALUE
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* @template RESULT := type('goog.Promise',
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* cond(isUnknown(VALUE), unknown(),
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* mapunion(VALUE, (V) =>
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* cond(isTemplatized(V) && sub(rawTypeOf(V), 'IThenable'),
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* templateTypeOf(V, 0),
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* cond(sub(V, 'Thenable'),
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* unknown(),
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* V)))))
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* =:
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*/
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goog.Promise.resolve = function(opt_value) {
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if (opt_value instanceof goog.Promise) {
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// Avoid creating a new object if we already have a promise object
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// of the correct type.
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return opt_value;
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}
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// Passing goog.nullFunction will cause the constructor to take an optimized
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// path that skips calling the resolver function.
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var promise = new goog.Promise(goog.nullFunction);
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promise.resolve_(goog.Promise.State_.FULFILLED, opt_value);
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return promise;
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};
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/**
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* @param {*=} opt_reason
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* @return {!goog.Promise} A new Promise that is immediately rejected with the
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* given reason.
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*/
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goog.Promise.reject = function(opt_reason) {
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return new goog.Promise(function(resolve, reject) { reject(opt_reason); });
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};
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/**
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* This is identical to
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* {@code goog.Promise.resolve(value).then(onFulfilled, onRejected)}, but it
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* avoids creating an unnecessary wrapper Promise when {@code value} is already
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* thenable.
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*
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* @param {?(goog.Thenable<TYPE>|Thenable|TYPE)} value
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* @param {function(TYPE): ?} onFulfilled
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* @param {function(*): *} onRejected
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* @template TYPE
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* @private
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*/
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goog.Promise.resolveThen_ = function(value, onFulfilled, onRejected) {
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var isThenable =
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goog.Promise.maybeThen_(value, onFulfilled, onRejected, null);
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if (!isThenable) {
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goog.async.run(goog.partial(onFulfilled, value));
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}
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};
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/**
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* @param {!Array<?(goog.Promise<TYPE>|goog.Thenable<TYPE>|Thenable|*)>}
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* promises
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* @return {!goog.Promise<TYPE>} A Promise that receives the result of the
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* first Promise (or Promise-like) input to settle immediately after it
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* settles.
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* @template TYPE
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*/
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goog.Promise.race = function(promises) {
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return new goog.Promise(function(resolve, reject) {
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if (!promises.length) {
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resolve(undefined);
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}
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for (var i = 0, promise; i < promises.length; i++) {
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promise = promises[i];
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goog.Promise.resolveThen_(promise, resolve, reject);
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}
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});
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};
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/**
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* @param {!Array<?(goog.Promise<TYPE>|goog.Thenable<TYPE>|Thenable|*)>}
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* promises
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* @return {!goog.Promise<!Array<TYPE>>} A Promise that receives a list of
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* every fulfilled value once every input Promise (or Promise-like) is
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* successfully fulfilled, or is rejected with the first rejection reason
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* immediately after it is rejected.
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* @template TYPE
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*/
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goog.Promise.all = function(promises) {
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return new goog.Promise(function(resolve, reject) {
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var toFulfill = promises.length;
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var values = [];
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if (!toFulfill) {
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resolve(values);
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return;
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}
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var onFulfill = function(index, value) {
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toFulfill--;
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values[index] = value;
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if (toFulfill == 0) {
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resolve(values);
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}
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};
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var onReject = function(reason) { reject(reason); };
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for (var i = 0, promise; i < promises.length; i++) {
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promise = promises[i];
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goog.Promise.resolveThen_(promise, goog.partial(onFulfill, i), onReject);
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}
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});
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};
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/**
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* @param {!Array<?(goog.Promise<TYPE>|goog.Thenable<TYPE>|Thenable|*)>}
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* promises
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* @return {!goog.Promise<!Array<{
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* fulfilled: boolean,
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* value: (TYPE|undefined),
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* reason: (*|undefined)}>>} A Promise that resolves with a list of
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* result objects once all input Promises (or Promise-like) have
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* settled. Each result object contains a 'fulfilled' boolean indicating
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* whether an input Promise was fulfilled or rejected. For fulfilled
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* Promises, the resulting value is stored in the 'value' field. For
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* rejected Promises, the rejection reason is stored in the 'reason'
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* field.
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* @template TYPE
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*/
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goog.Promise.allSettled = function(promises) {
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return new goog.Promise(function(resolve, reject) {
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var toSettle = promises.length;
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var results = [];
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if (!toSettle) {
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resolve(results);
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return;
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}
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var onSettled = function(index, fulfilled, result) {
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toSettle--;
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results[index] = fulfilled ? {fulfilled: true, value: result} :
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{fulfilled: false, reason: result};
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if (toSettle == 0) {
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resolve(results);
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}
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};
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for (var i = 0, promise; i < promises.length; i++) {
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promise = promises[i];
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goog.Promise.resolveThen_(
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promise, goog.partial(onSettled, i, true /* fulfilled */),
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goog.partial(onSettled, i, false /* fulfilled */));
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}
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});
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};
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/**
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* @param {!Array<?(goog.Promise<TYPE>|goog.Thenable<TYPE>|Thenable|*)>}
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* promises
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* @return {!goog.Promise<TYPE>} A Promise that receives the value of the first
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* input to be fulfilled, or is rejected with a list of every rejection
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* reason if all inputs are rejected.
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* @template TYPE
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*/
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goog.Promise.firstFulfilled = function(promises) {
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return new goog.Promise(function(resolve, reject) {
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var toReject = promises.length;
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var reasons = [];
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if (!toReject) {
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resolve(undefined);
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return;
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}
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var onFulfill = function(value) { resolve(value); };
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var onReject = function(index, reason) {
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toReject--;
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reasons[index] = reason;
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if (toReject == 0) {
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reject(reasons);
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}
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};
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for (var i = 0, promise; i < promises.length; i++) {
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promise = promises[i];
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goog.Promise.resolveThen_(promise, onFulfill, goog.partial(onReject, i));
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}
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});
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};
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/**
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* @return {!goog.promise.Resolver<TYPE>} Resolver wrapping the promise and its
|
|
* resolve / reject functions. Resolving or rejecting the resolver
|
|
* resolves or rejects the promise.
|
|
* @template TYPE
|
|
*/
|
|
goog.Promise.withResolver = function() {
|
|
var resolve, reject;
|
|
var promise = new goog.Promise(function(rs, rj) {
|
|
resolve = rs;
|
|
reject = rj;
|
|
});
|
|
return new goog.Promise.Resolver_(promise, resolve, reject);
|
|
};
|
|
|
|
|
|
/**
|
|
* Adds callbacks that will operate on the result of the Promise, returning a
|
|
* new child Promise.
|
|
*
|
|
* If the Promise is fulfilled, the {@code onFulfilled} callback will be invoked
|
|
* with the fulfillment value as argument, and the child Promise will be
|
|
* fulfilled with the return value of the callback. If the callback throws an
|
|
* exception, the child Promise will be rejected with the thrown value instead.
|
|
*
|
|
* If the Promise is rejected, the {@code onRejected} callback will be invoked
|
|
* with the rejection reason as argument, and the child Promise will be resolved
|
|
* with the return value or rejected with the thrown value of the callback.
|
|
*
|
|
* @override
|
|
*/
|
|
goog.Promise.prototype.then = function(
|
|
opt_onFulfilled, opt_onRejected, opt_context) {
|
|
|
|
if (opt_onFulfilled != null) {
|
|
goog.asserts.assertFunction(
|
|
opt_onFulfilled, 'opt_onFulfilled should be a function.');
|
|
}
|
|
if (opt_onRejected != null) {
|
|
goog.asserts.assertFunction(
|
|
opt_onRejected,
|
|
'opt_onRejected should be a function. Did you pass opt_context ' +
|
|
'as the second argument instead of the third?');
|
|
}
|
|
|
|
if (goog.Promise.LONG_STACK_TRACES) {
|
|
this.addStackTrace_(new Error('then'));
|
|
}
|
|
|
|
return this.addChildPromise_(
|
|
goog.isFunction(opt_onFulfilled) ? opt_onFulfilled : null,
|
|
goog.isFunction(opt_onRejected) ? opt_onRejected : null, opt_context);
|
|
};
|
|
goog.Thenable.addImplementation(goog.Promise);
|
|
|
|
|
|
/**
|
|
* Adds callbacks that will operate on the result of the Promise without
|
|
* returning a child Promise (unlike "then").
|
|
*
|
|
* If the Promise is fulfilled, the {@code onFulfilled} callback will be invoked
|
|
* with the fulfillment value as argument.
|
|
*
|
|
* If the Promise is rejected, the {@code onRejected} callback will be invoked
|
|
* with the rejection reason as argument.
|
|
*
|
|
* @param {?(function(this:THIS, TYPE):?)=} opt_onFulfilled A
|
|
* function that will be invoked with the fulfillment value if the Promise
|
|
* is fulfilled.
|
|
* @param {?(function(this:THIS, *): *)=} opt_onRejected A function that will
|
|
* be invoked with the rejection reason if the Promise is rejected.
|
|
* @param {THIS=} opt_context An optional context object that will be the
|
|
* execution context for the callbacks. By default, functions are executed
|
|
* with the default this.
|
|
* @package
|
|
* @template THIS
|
|
*/
|
|
goog.Promise.prototype.thenVoid = function(
|
|
opt_onFulfilled, opt_onRejected, opt_context) {
|
|
|
|
if (opt_onFulfilled != null) {
|
|
goog.asserts.assertFunction(
|
|
opt_onFulfilled, 'opt_onFulfilled should be a function.');
|
|
}
|
|
if (opt_onRejected != null) {
|
|
goog.asserts.assertFunction(
|
|
opt_onRejected,
|
|
'opt_onRejected should be a function. Did you pass opt_context ' +
|
|
'as the second argument instead of the third?');
|
|
}
|
|
|
|
if (goog.Promise.LONG_STACK_TRACES) {
|
|
this.addStackTrace_(new Error('then'));
|
|
}
|
|
|
|
// Note: no default rejection handler is provided here as we need to
|
|
// distinguish unhandled rejections.
|
|
this.addCallbackEntry_(
|
|
goog.Promise.getCallbackEntry_(
|
|
opt_onFulfilled || goog.nullFunction, opt_onRejected || null,
|
|
opt_context));
|
|
};
|
|
|
|
|
|
/**
|
|
* Adds a callback that will be invoked when the Promise is settled (fulfilled
|
|
* or rejected). The callback receives no argument, and no new child Promise is
|
|
* created. This is useful for ensuring that cleanup takes place after certain
|
|
* asynchronous operations. Callbacks added with {@code thenAlways} will be
|
|
* executed in the same order with other calls to {@code then},
|
|
* {@code thenAlways}, or {@code thenCatch}.
|
|
*
|
|
* Since it does not produce a new child Promise, cancellation propagation is
|
|
* not prevented by adding callbacks with {@code thenAlways}. A Promise that has
|
|
* a cleanup handler added with {@code thenAlways} will be canceled if all of
|
|
* its children created by {@code then} (or {@code thenCatch}) are canceled.
|
|
* Additionally, since any rejections are not passed to the callback, it does
|
|
* not stop the unhandled rejection handler from running.
|
|
*
|
|
* @param {function(this:THIS): void} onSettled A function that will be invoked
|
|
* when the Promise is settled (fulfilled or rejected).
|
|
* @param {THIS=} opt_context An optional context object that will be the
|
|
* execution context for the callbacks. By default, functions are executed
|
|
* in the global scope.
|
|
* @return {!goog.Promise<TYPE>} This Promise, for chaining additional calls.
|
|
* @template THIS
|
|
*/
|
|
goog.Promise.prototype.thenAlways = function(onSettled, opt_context) {
|
|
if (goog.Promise.LONG_STACK_TRACES) {
|
|
this.addStackTrace_(new Error('thenAlways'));
|
|
}
|
|
|
|
var entry = goog.Promise.getCallbackEntry_(onSettled, onSettled, opt_context);
|
|
entry.always = true;
|
|
this.addCallbackEntry_(entry);
|
|
return this;
|
|
};
|
|
|
|
|
|
/**
|
|
* Adds a callback that will be invoked only if the Promise is rejected. This
|
|
* is equivalent to {@code then(null, onRejected)}.
|
|
*
|
|
* @param {function(this:THIS, *): *} onRejected A function that will be
|
|
* invoked with the rejection reason if the Promise is rejected.
|
|
* @param {THIS=} opt_context An optional context object that will be the
|
|
* execution context for the callbacks. By default, functions are executed
|
|
* in the global scope.
|
|
* @return {!goog.Promise} A new Promise that will receive the result of the
|
|
* callback.
|
|
* @template THIS
|
|
*/
|
|
goog.Promise.prototype.thenCatch = function(onRejected, opt_context) {
|
|
if (goog.Promise.LONG_STACK_TRACES) {
|
|
this.addStackTrace_(new Error('thenCatch'));
|
|
}
|
|
return this.addChildPromise_(null, onRejected, opt_context);
|
|
};
|
|
|
|
|
|
/**
|
|
* Cancels the Promise if it is still pending by rejecting it with a cancel
|
|
* Error. No action is performed if the Promise is already resolved.
|
|
*
|
|
* All child Promises of the canceled Promise will be rejected with the same
|
|
* cancel error, as with normal Promise rejection. If the Promise to be canceled
|
|
* is the only child of a pending Promise, the parent Promise will also be
|
|
* canceled. Cancellation may propagate upward through multiple generations.
|
|
*
|
|
* @param {string=} opt_message An optional debugging message for describing the
|
|
* cancellation reason.
|
|
*/
|
|
goog.Promise.prototype.cancel = function(opt_message) {
|
|
if (this.state_ == goog.Promise.State_.PENDING) {
|
|
goog.async.run(function() {
|
|
var err = new goog.Promise.CancellationError(opt_message);
|
|
this.cancelInternal_(err);
|
|
}, this);
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Cancels this Promise with the given error.
|
|
*
|
|
* @param {!Error} err The cancellation error.
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.cancelInternal_ = function(err) {
|
|
if (this.state_ == goog.Promise.State_.PENDING) {
|
|
if (this.parent_) {
|
|
// Cancel the Promise and remove it from the parent's child list.
|
|
this.parent_.cancelChild_(this, err);
|
|
this.parent_ = null;
|
|
} else {
|
|
this.resolve_(goog.Promise.State_.REJECTED, err);
|
|
}
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Cancels a child Promise from the list of callback entries. If the Promise has
|
|
* not already been resolved, reject it with a cancel error. If there are no
|
|
* other children in the list of callback entries, propagate the cancellation
|
|
* by canceling this Promise as well.
|
|
*
|
|
* @param {!goog.Promise} childPromise The Promise to cancel.
|
|
* @param {!Error} err The cancel error to use for rejecting the Promise.
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.cancelChild_ = function(childPromise, err) {
|
|
if (!this.callbackEntries_) {
|
|
return;
|
|
}
|
|
var childCount = 0;
|
|
var childEntry = null;
|
|
var beforeChildEntry = null;
|
|
|
|
// Find the callback entry for the childPromise, and count whether there are
|
|
// additional child Promises.
|
|
for (var entry = this.callbackEntries_; entry; entry = entry.next) {
|
|
if (!entry.always) {
|
|
childCount++;
|
|
if (entry.child == childPromise) {
|
|
childEntry = entry;
|
|
}
|
|
if (childEntry && childCount > 1) {
|
|
break;
|
|
}
|
|
}
|
|
if (!childEntry) {
|
|
beforeChildEntry = entry;
|
|
}
|
|
}
|
|
|
|
// Can a child entry be missing?
|
|
|
|
// If the child Promise was the only child, cancel this Promise as well.
|
|
// Otherwise, reject only the child Promise with the cancel error.
|
|
if (childEntry) {
|
|
if (this.state_ == goog.Promise.State_.PENDING && childCount == 1) {
|
|
this.cancelInternal_(err);
|
|
} else {
|
|
if (beforeChildEntry) {
|
|
this.removeEntryAfter_(beforeChildEntry);
|
|
} else {
|
|
this.popEntry_();
|
|
}
|
|
|
|
this.executeCallback_(childEntry, goog.Promise.State_.REJECTED, err);
|
|
}
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Adds a callback entry to the current Promise, and schedules callback
|
|
* execution if the Promise has already been settled.
|
|
*
|
|
* @param {goog.Promise.CallbackEntry_} callbackEntry Record containing
|
|
* {@code onFulfilled} and {@code onRejected} callbacks to execute after
|
|
* the Promise is settled.
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.addCallbackEntry_ = function(callbackEntry) {
|
|
if (!this.hasEntry_() && (this.state_ == goog.Promise.State_.FULFILLED ||
|
|
this.state_ == goog.Promise.State_.REJECTED)) {
|
|
this.scheduleCallbacks_();
|
|
}
|
|
this.queueEntry_(callbackEntry);
|
|
};
|
|
|
|
|
|
/**
|
|
* Creates a child Promise and adds it to the callback entry list. The result of
|
|
* the child Promise is determined by the state of the parent Promise and the
|
|
* result of the {@code onFulfilled} or {@code onRejected} callbacks as
|
|
* specified in the Promise resolution procedure.
|
|
*
|
|
* @see http://promisesaplus.com/#the__method
|
|
*
|
|
* @param {?function(this:THIS, TYPE):
|
|
* (RESULT|goog.Promise<RESULT>|Thenable)} onFulfilled A callback that
|
|
* will be invoked if the Promise is fulfilled, or null.
|
|
* @param {?function(this:THIS, *): *} onRejected A callback that will be
|
|
* invoked if the Promise is rejected, or null.
|
|
* @param {THIS=} opt_context An optional execution context for the callbacks.
|
|
* in the default calling context.
|
|
* @return {!goog.Promise} The child Promise.
|
|
* @template RESULT,THIS
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.addChildPromise_ = function(
|
|
onFulfilled, onRejected, opt_context) {
|
|
|
|
/** @type {goog.Promise.CallbackEntry_} */
|
|
var callbackEntry = goog.Promise.getCallbackEntry_(null, null, null);
|
|
|
|
callbackEntry.child = new goog.Promise(function(resolve, reject) {
|
|
// Invoke onFulfilled, or resolve with the parent's value if absent.
|
|
callbackEntry.onFulfilled = onFulfilled ? function(value) {
|
|
try {
|
|
var result = onFulfilled.call(opt_context, value);
|
|
resolve(result);
|
|
} catch (err) {
|
|
reject(err);
|
|
}
|
|
} : resolve;
|
|
|
|
// Invoke onRejected, or reject with the parent's reason if absent.
|
|
callbackEntry.onRejected = onRejected ? function(reason) {
|
|
try {
|
|
var result = onRejected.call(opt_context, reason);
|
|
if (!goog.isDef(result) &&
|
|
reason instanceof goog.Promise.CancellationError) {
|
|
// Propagate cancellation to children if no other result is returned.
|
|
reject(reason);
|
|
} else {
|
|
resolve(result);
|
|
}
|
|
} catch (err) {
|
|
reject(err);
|
|
}
|
|
} : reject;
|
|
});
|
|
|
|
callbackEntry.child.parent_ = this;
|
|
this.addCallbackEntry_(callbackEntry);
|
|
return callbackEntry.child;
|
|
};
|
|
|
|
|
|
/**
|
|
* Unblocks the Promise and fulfills it with the given value.
|
|
*
|
|
* @param {TYPE} value
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.unblockAndFulfill_ = function(value) {
|
|
goog.asserts.assert(this.state_ == goog.Promise.State_.BLOCKED);
|
|
this.state_ = goog.Promise.State_.PENDING;
|
|
this.resolve_(goog.Promise.State_.FULFILLED, value);
|
|
};
|
|
|
|
|
|
/**
|
|
* Unblocks the Promise and rejects it with the given rejection reason.
|
|
*
|
|
* @param {*} reason
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.unblockAndReject_ = function(reason) {
|
|
goog.asserts.assert(this.state_ == goog.Promise.State_.BLOCKED);
|
|
this.state_ = goog.Promise.State_.PENDING;
|
|
this.resolve_(goog.Promise.State_.REJECTED, reason);
|
|
};
|
|
|
|
|
|
/**
|
|
* Attempts to resolve a Promise with a given resolution state and value. This
|
|
* is a no-op if the given Promise has already been resolved.
|
|
*
|
|
* If the given result is a Thenable (such as another Promise), the Promise will
|
|
* be settled with the same state and result as the Thenable once it is itself
|
|
* settled.
|
|
*
|
|
* If the given result is not a Thenable, the Promise will be settled (fulfilled
|
|
* or rejected) with that result based on the given state.
|
|
*
|
|
* @see http://promisesaplus.com/#the_promise_resolution_procedure
|
|
*
|
|
* @param {goog.Promise.State_} state
|
|
* @param {*} x The result to apply to the Promise.
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.resolve_ = function(state, x) {
|
|
if (this.state_ != goog.Promise.State_.PENDING) {
|
|
return;
|
|
}
|
|
|
|
if (this === x) {
|
|
state = goog.Promise.State_.REJECTED;
|
|
x = new TypeError('Promise cannot resolve to itself');
|
|
}
|
|
|
|
this.state_ = goog.Promise.State_.BLOCKED;
|
|
var isThenable = goog.Promise.maybeThen_(
|
|
x, this.unblockAndFulfill_, this.unblockAndReject_, this);
|
|
if (isThenable) {
|
|
return;
|
|
}
|
|
|
|
this.result_ = x;
|
|
this.state_ = state;
|
|
// Since we can no longer be canceled, remove link to parent, so that the
|
|
// child promise does not keep the parent promise alive.
|
|
this.parent_ = null;
|
|
this.scheduleCallbacks_();
|
|
|
|
if (state == goog.Promise.State_.REJECTED &&
|
|
!(x instanceof goog.Promise.CancellationError)) {
|
|
goog.Promise.addUnhandledRejection_(this, x);
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Invokes the "then" method of an input value if that value is a Thenable. This
|
|
* is a no-op if the value is not thenable.
|
|
*
|
|
* @param {?} value A potentially thenable value.
|
|
* @param {!Function} onFulfilled
|
|
* @param {!Function} onRejected
|
|
* @param {?} context
|
|
* @return {boolean} Whether the input value was thenable.
|
|
* @private
|
|
*/
|
|
goog.Promise.maybeThen_ = function(value, onFulfilled, onRejected, context) {
|
|
if (value instanceof goog.Promise) {
|
|
value.thenVoid(onFulfilled, onRejected, context);
|
|
return true;
|
|
} else if (goog.Thenable.isImplementedBy(value)) {
|
|
value = /** @type {!goog.Thenable} */ (value);
|
|
value.then(onFulfilled, onRejected, context);
|
|
return true;
|
|
} else if (goog.isObject(value)) {
|
|
try {
|
|
var then = value['then'];
|
|
if (goog.isFunction(then)) {
|
|
goog.Promise.tryThen_(value, then, onFulfilled, onRejected, context);
|
|
return true;
|
|
}
|
|
} catch (e) {
|
|
onRejected.call(context, e);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
};
|
|
|
|
|
|
/**
|
|
* Attempts to call the {@code then} method on an object in the hopes that it is
|
|
* a Promise-compatible instance. This allows interoperation between different
|
|
* Promise implementations, however a non-compliant object may cause a Promise
|
|
* to hang indefinitely. If the {@code then} method throws an exception, the
|
|
* dependent Promise will be rejected with the thrown value.
|
|
*
|
|
* @see http://promisesaplus.com/#point-70
|
|
*
|
|
* @param {Thenable} thenable An object with a {@code then} method that may be
|
|
* compatible with the Promise/A+ specification.
|
|
* @param {!Function} then The {@code then} method of the Thenable object.
|
|
* @param {!Function} onFulfilled
|
|
* @param {!Function} onRejected
|
|
* @param {*} context
|
|
* @private
|
|
*/
|
|
goog.Promise.tryThen_ = function(
|
|
thenable, then, onFulfilled, onRejected, context) {
|
|
|
|
var called = false;
|
|
var resolve = function(value) {
|
|
if (!called) {
|
|
called = true;
|
|
onFulfilled.call(context, value);
|
|
}
|
|
};
|
|
|
|
var reject = function(reason) {
|
|
if (!called) {
|
|
called = true;
|
|
onRejected.call(context, reason);
|
|
}
|
|
};
|
|
|
|
try {
|
|
then.call(thenable, resolve, reject);
|
|
} catch (e) {
|
|
reject(e);
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Executes the pending callbacks of a settled Promise after a timeout.
|
|
*
|
|
* Section 2.2.4 of the Promises/A+ specification requires that Promise
|
|
* callbacks must only be invoked from a call stack that only contains Promise
|
|
* implementation code, which we accomplish by invoking callback execution after
|
|
* a timeout. If {@code startExecution_} is called multiple times for the same
|
|
* Promise, the callback chain will be evaluated only once. Additional callbacks
|
|
* may be added during the evaluation phase, and will be executed in the same
|
|
* event loop.
|
|
*
|
|
* All Promises added to the waiting list during the same browser event loop
|
|
* will be executed in one batch to avoid using a separate timeout per Promise.
|
|
*
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.scheduleCallbacks_ = function() {
|
|
if (!this.executing_) {
|
|
this.executing_ = true;
|
|
goog.async.run(this.executeCallbacks_, this);
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* @return {boolean} Whether there are any pending callbacks queued.
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.hasEntry_ = function() {
|
|
return !!this.callbackEntries_;
|
|
};
|
|
|
|
|
|
/**
|
|
* @param {goog.Promise.CallbackEntry_} entry
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.queueEntry_ = function(entry) {
|
|
goog.asserts.assert(entry.onFulfilled != null);
|
|
|
|
if (this.callbackEntriesTail_) {
|
|
this.callbackEntriesTail_.next = entry;
|
|
this.callbackEntriesTail_ = entry;
|
|
} else {
|
|
// It the work queue was empty set the head too.
|
|
this.callbackEntries_ = entry;
|
|
this.callbackEntriesTail_ = entry;
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* @return {goog.Promise.CallbackEntry_} entry
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.popEntry_ = function() {
|
|
var entry = null;
|
|
if (this.callbackEntries_) {
|
|
entry = this.callbackEntries_;
|
|
this.callbackEntries_ = entry.next;
|
|
entry.next = null;
|
|
}
|
|
// It the work queue is empty clear the tail too.
|
|
if (!this.callbackEntries_) {
|
|
this.callbackEntriesTail_ = null;
|
|
}
|
|
|
|
if (entry != null) {
|
|
goog.asserts.assert(entry.onFulfilled != null);
|
|
}
|
|
return entry;
|
|
};
|
|
|
|
|
|
/**
|
|
* @param {goog.Promise.CallbackEntry_} previous
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.removeEntryAfter_ = function(previous) {
|
|
goog.asserts.assert(this.callbackEntries_);
|
|
goog.asserts.assert(previous != null);
|
|
// If the last entry is being removed, update the tail
|
|
if (previous.next == this.callbackEntriesTail_) {
|
|
this.callbackEntriesTail_ = previous;
|
|
}
|
|
|
|
previous.next = previous.next.next;
|
|
};
|
|
|
|
|
|
/**
|
|
* Executes all pending callbacks for this Promise.
|
|
*
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.executeCallbacks_ = function() {
|
|
var entry = null;
|
|
while (entry = this.popEntry_()) {
|
|
if (goog.Promise.LONG_STACK_TRACES) {
|
|
this.currentStep_++;
|
|
}
|
|
this.executeCallback_(entry, this.state_, this.result_);
|
|
}
|
|
this.executing_ = false;
|
|
};
|
|
|
|
|
|
/**
|
|
* Executes a pending callback for this Promise. Invokes an {@code onFulfilled}
|
|
* or {@code onRejected} callback based on the settled state of the Promise.
|
|
*
|
|
* @param {!goog.Promise.CallbackEntry_} callbackEntry An entry containing the
|
|
* onFulfilled and/or onRejected callbacks for this step.
|
|
* @param {goog.Promise.State_} state The resolution status of the Promise,
|
|
* either FULFILLED or REJECTED.
|
|
* @param {*} result The settled result of the Promise.
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.executeCallback_ = function(
|
|
callbackEntry, state, result) {
|
|
// Cancel an unhandled rejection if the then/thenVoid call had an onRejected.
|
|
if (state == goog.Promise.State_.REJECTED && callbackEntry.onRejected &&
|
|
!callbackEntry.always) {
|
|
this.removeUnhandledRejection_();
|
|
}
|
|
|
|
if (callbackEntry.child) {
|
|
// When the parent is settled, the child no longer needs to hold on to it,
|
|
// as the parent can no longer be canceled.
|
|
callbackEntry.child.parent_ = null;
|
|
goog.Promise.invokeCallback_(callbackEntry, state, result);
|
|
} else {
|
|
// Callbacks created with thenAlways or thenVoid do not have the rejection
|
|
// handling code normally set up in the child Promise.
|
|
try {
|
|
callbackEntry.always ?
|
|
callbackEntry.onFulfilled.call(callbackEntry.context) :
|
|
goog.Promise.invokeCallback_(callbackEntry, state, result);
|
|
} catch (err) {
|
|
goog.Promise.handleRejection_.call(null, err);
|
|
}
|
|
}
|
|
goog.Promise.returnEntry_(callbackEntry);
|
|
};
|
|
|
|
|
|
/**
|
|
* Executes the onFulfilled or onRejected callback for a callbackEntry.
|
|
*
|
|
* @param {!goog.Promise.CallbackEntry_} callbackEntry
|
|
* @param {goog.Promise.State_} state
|
|
* @param {*} result
|
|
* @private
|
|
*/
|
|
goog.Promise.invokeCallback_ = function(callbackEntry, state, result) {
|
|
if (state == goog.Promise.State_.FULFILLED) {
|
|
callbackEntry.onFulfilled.call(callbackEntry.context, result);
|
|
} else if (callbackEntry.onRejected) {
|
|
callbackEntry.onRejected.call(callbackEntry.context, result);
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Records a stack trace entry for functions that call {@code then} or the
|
|
* Promise constructor. May be disabled by unsetting {@code LONG_STACK_TRACES}.
|
|
*
|
|
* @param {!Error} err An Error object created by the calling function for
|
|
* providing a stack trace.
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.addStackTrace_ = function(err) {
|
|
if (goog.Promise.LONG_STACK_TRACES && goog.isString(err.stack)) {
|
|
// Extract the third line of the stack trace, which is the entry for the
|
|
// user function that called into Promise code.
|
|
var trace = err.stack.split('\n', 4)[3];
|
|
var message = err.message;
|
|
|
|
// Pad the message to align the traces.
|
|
message += Array(11 - message.length).join(' ');
|
|
this.stack_.push(message + trace);
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Adds extra stack trace information to an exception for the list of
|
|
* asynchronous {@code then} calls that have been run for this Promise. Stack
|
|
* trace information is recorded in {@see #addStackTrace_}, and appended to
|
|
* rethrown errors when {@code LONG_STACK_TRACES} is enabled.
|
|
*
|
|
* @param {*} err An unhandled exception captured during callback execution.
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.appendLongStack_ = function(err) {
|
|
if (goog.Promise.LONG_STACK_TRACES && err && goog.isString(err.stack) &&
|
|
this.stack_.length) {
|
|
var longTrace = ['Promise trace:'];
|
|
|
|
for (var promise = this; promise; promise = promise.parent_) {
|
|
for (var i = this.currentStep_; i >= 0; i--) {
|
|
longTrace.push(promise.stack_[i]);
|
|
}
|
|
longTrace.push(
|
|
'Value: ' +
|
|
'[' + (promise.state_ == goog.Promise.State_.REJECTED ? 'REJECTED' :
|
|
'FULFILLED') +
|
|
'] ' +
|
|
'<' + String(promise.result_) + '>');
|
|
}
|
|
err.stack += '\n\n' + longTrace.join('\n');
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Marks this rejected Promise as having being handled. Also marks any parent
|
|
* Promises in the rejected state as handled. The rejection handler will no
|
|
* longer be invoked for this Promise (if it has not been called already).
|
|
*
|
|
* @private
|
|
*/
|
|
goog.Promise.prototype.removeUnhandledRejection_ = function() {
|
|
if (goog.Promise.UNHANDLED_REJECTION_DELAY > 0) {
|
|
for (var p = this; p && p.unhandledRejectionId_; p = p.parent_) {
|
|
goog.global.clearTimeout(p.unhandledRejectionId_);
|
|
p.unhandledRejectionId_ = 0;
|
|
}
|
|
} else if (goog.Promise.UNHANDLED_REJECTION_DELAY == 0) {
|
|
for (var p = this; p && p.hadUnhandledRejection_; p = p.parent_) {
|
|
p.hadUnhandledRejection_ = false;
|
|
}
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* Marks this rejected Promise as unhandled. If no {@code onRejected} callback
|
|
* is called for this Promise before the {@code UNHANDLED_REJECTION_DELAY}
|
|
* expires, the reason will be passed to the unhandled rejection handler. The
|
|
* handler typically rethrows the rejection reason so that it becomes visible in
|
|
* the developer console.
|
|
*
|
|
* @param {!goog.Promise} promise The rejected Promise.
|
|
* @param {*} reason The Promise rejection reason.
|
|
* @private
|
|
*/
|
|
goog.Promise.addUnhandledRejection_ = function(promise, reason) {
|
|
if (goog.Promise.UNHANDLED_REJECTION_DELAY > 0) {
|
|
promise.unhandledRejectionId_ = goog.global.setTimeout(function() {
|
|
promise.appendLongStack_(reason);
|
|
goog.Promise.handleRejection_.call(null, reason);
|
|
}, goog.Promise.UNHANDLED_REJECTION_DELAY);
|
|
|
|
} else if (goog.Promise.UNHANDLED_REJECTION_DELAY == 0) {
|
|
promise.hadUnhandledRejection_ = true;
|
|
goog.async.run(function() {
|
|
if (promise.hadUnhandledRejection_) {
|
|
promise.appendLongStack_(reason);
|
|
goog.Promise.handleRejection_.call(null, reason);
|
|
}
|
|
});
|
|
}
|
|
};
|
|
|
|
|
|
/**
|
|
* A method that is invoked with the rejection reasons for Promises that are
|
|
* rejected but have no {@code onRejected} callbacks registered yet.
|
|
* @type {function(*)}
|
|
* @private
|
|
*/
|
|
goog.Promise.handleRejection_ = goog.async.throwException;
|
|
|
|
|
|
/**
|
|
* Sets a handler that will be called with reasons from unhandled rejected
|
|
* Promises. If the rejected Promise (or one of its descendants) has an
|
|
* {@code onRejected} callback registered, the rejection will be considered
|
|
* handled, and the rejection handler will not be called.
|
|
*
|
|
* By default, unhandled rejections are rethrown so that the error may be
|
|
* captured by the developer console or a {@code window.onerror} handler.
|
|
*
|
|
* @param {function(*)} handler A function that will be called with reasons from
|
|
* rejected Promises. Defaults to {@code goog.async.throwException}.
|
|
*/
|
|
goog.Promise.setUnhandledRejectionHandler = function(handler) {
|
|
goog.Promise.handleRejection_ = handler;
|
|
};
|
|
|
|
|
|
|
|
/**
|
|
* Error used as a rejection reason for canceled Promises.
|
|
*
|
|
* @param {string=} opt_message
|
|
* @constructor
|
|
* @extends {goog.debug.Error}
|
|
* @final
|
|
*/
|
|
goog.Promise.CancellationError = function(opt_message) {
|
|
goog.Promise.CancellationError.base(this, 'constructor', opt_message);
|
|
};
|
|
goog.inherits(goog.Promise.CancellationError, goog.debug.Error);
|
|
|
|
|
|
/** @override */
|
|
goog.Promise.CancellationError.prototype.name = 'cancel';
|
|
|
|
|
|
|
|
/**
|
|
* Internal implementation of the resolver interface.
|
|
*
|
|
* @param {!goog.Promise<TYPE>} promise
|
|
* @param {function((TYPE|goog.Promise<TYPE>|Thenable)=)} resolve
|
|
* @param {function(*=): void} reject
|
|
* @implements {goog.promise.Resolver<TYPE>}
|
|
* @final @struct
|
|
* @constructor
|
|
* @private
|
|
* @template TYPE
|
|
*/
|
|
goog.Promise.Resolver_ = function(promise, resolve, reject) {
|
|
/** @const */
|
|
this.promise = promise;
|
|
|
|
/** @const */
|
|
this.resolve = resolve;
|
|
|
|
/** @const */
|
|
this.reject = reject;
|
|
};
|