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// Copyright 2007 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 Definition the goog.debug.RelativeTimeProvider class.
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 *
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 */
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goog.provide('goog.debug.RelativeTimeProvider');
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/**
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 * A simple object to keep track of a timestamp considered the start of
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 * something. The main use is for the logger system to maintain a start time
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 * that is occasionally reset. For example, in Gmail, we reset this relative
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 * time at the start of a user action so that timings are offset from the
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 * beginning of the action. This class also provides a singleton as the default
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 * behavior for most use cases is to share the same start time.
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 *
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 * @constructor
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 * @final
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 */
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goog.debug.RelativeTimeProvider = function() {
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  /**
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   * The start time.
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   * @type {number}
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   * @private
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   */
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  this.relativeTimeStart_ = goog.now();
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};
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/**
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 * Default instance.
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 * @type {goog.debug.RelativeTimeProvider}
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 * @private
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 */
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goog.debug.RelativeTimeProvider.defaultInstance_ =
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    new goog.debug.RelativeTimeProvider();
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/**
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 * Sets the start time to the specified time.
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 * @param {number} timeStamp The start time.
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 */
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goog.debug.RelativeTimeProvider.prototype.set = function(timeStamp) {
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  this.relativeTimeStart_ = timeStamp;
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};
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/**
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 * Resets the start time to now.
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 */
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goog.debug.RelativeTimeProvider.prototype.reset = function() {
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  this.set(goog.now());
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};
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/**
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 * @return {number} The start time.
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 */
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goog.debug.RelativeTimeProvider.prototype.get = function() {
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  return this.relativeTimeStart_;
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};
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/**
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 * @return {goog.debug.RelativeTimeProvider} The default instance.
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 */
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goog.debug.RelativeTimeProvider.getDefaultInstance = function() {
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  return goog.debug.RelativeTimeProvider.defaultInstance_;
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};
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