Stops accumulating performance statistics on the Chrome App.

remoting/webapp/base/js/stats_accumulator.js

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-/**
- * @fileoverview
- * The webapp reads the plugin's connection statistics frequently (once per
- * second). It logs statistics to the server less frequently, to keep
- * bandwidth and storage costs down. This class bridges that gap, by
- * accumulating high-frequency numeric data, and providing statistics
- * summarising that data.
- */
-
-'use strict';
-
-/** @suppress {duplicate} */
-var remoting = remoting || {};
-
-(function() {
-
-/**
- * @constructor
- */
-remoting.StatsAccumulator = function() {
-  /**
-   * A map from names to lists of values.
-   * @private {Object<Array<number>>}
-   */
-  this.valueLists_ = {};
-
-  /**
-   * The first time, after this object was most recently initialized or emptied,
-   * at which a value was added to this object.
-   * @private {?number}
-   */
-  this.timeOfFirstValue_ = null;
-};
-
-/**
- * @param {Object<number>} stats
- * @return {boolean} true if there is any non-zero value in stats, false
- *     otherwise.
- */
-function hasValidField(stats) {
-  for (var key in stats) {
-    if (stats[key] !== 0) {
-      return true;
-    }
-  }
-  return false;
-}
-
-/**
- * Adds values to this object. Do nothing if newValues has no valid field.
- *
- * @param {Object<number>} newValues
- */
-remoting.StatsAccumulator.prototype.add = function(newValues) {
-  if (!hasValidField(newValues)) {
-    return;
-  }
-  for (var key in newValues) {
-    this.getValueList(key).push(newValues[key]);
-  }
-  if (this.timeOfFirstValue_ === null) {
-    this.timeOfFirstValue_ = new Date().getTime();
-  }
-};
-
-/**
- * Empties this object.
- */
-remoting.StatsAccumulator.prototype.empty = function() {
-  this.valueLists_ = {};
-  this.timeOfFirstValue_ = null;
-};
-
-/**
- * Gets the number of milliseconds since the first value was added to this
- * object, after this object was most recently initialized or emptied.
- *
- * @return {number} milliseconds since the first value
- */
-remoting.StatsAccumulator.prototype.getTimeSinceFirstValue = function() {
-  if (this.timeOfFirstValue_ === null) {
-    return 0;
-  }
-  return new Date().getTime() - this.timeOfFirstValue_;
-};
-
-/**
- * Calculates the mean of the values for a given key.
- *
- * @param {string} key
- * @return {number} the mean of the values for that key
- */
-remoting.StatsAccumulator.prototype.calcMean = function(key) {
-  /**
-   * @param {Array<number>} values
-   * @return {number}
-   */
-  var calcMean = function(values) {
-    if (values.length == 0) {
-      return 0.0;
-    }
-    var sum = 0;
-    for (var i = 0; i < values.length; i++) {
-      sum += values[i];
-    }
-    return sum / values.length;
-  };
-  return this.map(key, calcMean);
-};
-
-/**
- * Finds the max of the values for a given key.
- *
- * @param {string} key
- * @return {number} the max of the values for that key
- */
-remoting.StatsAccumulator.prototype.calcMax = function(key) {
-  /**
-   * @param {Array<number>} values
-   * @return {number}
-   */
-  var calcMax = function(values) {
-    if (!values || !values.length) {
-      return 0;
-    }
-    return Math.max.apply(null, values);
-  };
-  return this.map(key, calcMax);
-};
-
-/**
- * Applies a given map to the list of values for a given key.
- *
- * @param {string} key
- * @param {function(Array<number>): number} map
- * @return {number} the result of applying that map to the list of values for
- *     that key
- */
-remoting.StatsAccumulator.prototype.map = function(key, map) {
-  return map(this.getValueList(key));
-};
-
-/**
- * Gets the list of values for a given key.
- * If this object contains no values for that key, then this routine creates
- * an empty list, stores it in this object, and returns it.
- *
- * @private
- * @param {string} key
- * @return {Array<number>} the list of values for that key
- */
-remoting.StatsAccumulator.prototype.getValueList = function(key) {
-  var valueList = this.valueLists_[key];
-  if (!valueList) {
-    valueList = [];
-    this.valueLists_[key] = valueList;
-  }
-  return valueList;
-};
-
-/**
- * @return {?remoting.ClientSession.PerfStats} returns null if all fields are
- *     zero.
- */
-remoting.StatsAccumulator.prototype.getPerfStats = function() {
-  var stats = new remoting.ClientSession.PerfStats();
-  stats.videoBandwidth = this.calcMean('videoBandwidth');
-  stats.captureLatency = this.calcMean('captureLatency');
-  stats.maxCaptureLatency = this.calcMax('maxCaptureLatency');
-  stats.encodeLatency = this.calcMean('encodeLatency');
-  stats.maxEncodeLatency = this.calcMax('maxEncodeLatency');
-  stats.decodeLatency = this.calcMean('decodeLatency');
-  stats.maxDecodeLatency = this.calcMax('maxDecodeLatency');
-  stats.renderLatency = this.calcMean('renderLatency');
-  stats.maxRenderLatency = this.calcMax('maxRenderLatency');
-  stats.roundtripLatency = this.calcMean('roundtripLatency');
-  stats.maxRoundtripLatency = this.calcMax('maxRoundtripLatency');
-
-  return hasValidField(stats) ? stats : null;
-};
-
-})();