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// Copyright 2012 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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/**
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 * @fileoverview Defines an interface that represents a Result.
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 *
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 * NOTE: goog.result is soft deprecated - we expect to replace this and
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 * {@link goog.async.Deferred} with {@link goog.Promise}.
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 */
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goog.provide('goog.result.Result');
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goog.require('goog.Thenable');
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/**
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 * A Result object represents a value returned by an asynchronous
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 * operation at some point in the future (e.g. a network fetch). This is akin
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 * to a 'Promise' or a 'Future' in other languages and frameworks.
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 *
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 * @interface
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 * @extends {goog.Thenable}
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 * @deprecated Use {@link goog.Promise} instead - http://go/promisemigration
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 */
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goog.result.Result = function() {};
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/**
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 * Attaches handlers to be called when the value of this Result is available.
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 * Handlers are called in the order they were added by wait.
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 *
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 * @param {function(this:T, !goog.result.Result)} handler The function called
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 *     when the value is available. The function is passed the Result object as
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 *     the only argument.
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 * @param {T=} opt_scope Optional scope for the handler.
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 * @template T
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 */
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goog.result.Result.prototype.wait = function(handler, opt_scope) {};
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/**
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 * The States this object can be in.
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 *
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 * @enum {string}
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 * @deprecated Use {@link goog.Promise} instead - http://go/promisemigration
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 */
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goog.result.Result.State = {
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  /** The operation was a success and the value is available. */
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  SUCCESS: 'success',
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  /** The operation resulted in an error. */
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  ERROR: 'error',
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  /** The operation is incomplete and the value is not yet available. */
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  PENDING: 'pending'
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};
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/**
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 * @return {!goog.result.Result.State} The state of this Result.
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 */
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goog.result.Result.prototype.getState = function() {};
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/**
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 * @return {*} The value of this Result. Will return undefined if the Result is
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 *     pending or was an error.
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 */
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goog.result.Result.prototype.getValue = function() {};
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/**
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 * @return {*} The error slug for this Result. Will return undefined if the
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 *     Result was a success, the error slug was not set, or if the Result is
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 *     pending.
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 */
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goog.result.Result.prototype.getError = function() {};
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/**
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 * Cancels the current Result, invoking the canceler function, if set.
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 *
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 * @return {boolean} Whether the Result was canceled.
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 */
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goog.result.Result.prototype.cancel = function() {};
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/**
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 * @return {boolean} Whether this Result was canceled.
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 */
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goog.result.Result.prototype.isCanceled = function() {};
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/**
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 * The value to be passed to the error handlers invoked upon cancellation.
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 * @constructor
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 * @extends {Error}
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 * @final
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 * @deprecated Use {@link goog.Promise} instead - http://go/promisemigration
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 */
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goog.result.Result.CancelError = function() {
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  // Note that this does not derive from goog.debug.Error in order to prevent
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  // stack trace capture and reduce the amount of garbage generated during a
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  // cancel() operation.
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};
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goog.inherits(goog.result.Result.CancelError, Error);
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