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1 /* This Source Code Form is subject to the terms of the Mozilla Public |
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2 * License, v. 2.0. If a copy of the MPL was not distributed with this file, |
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3 * You can obtain one at http://mozilla.org/MPL/2.0/. */ |
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4 |
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5 const Cc = Components.classes; |
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6 const Ci = Components.interfaces; |
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7 const Cu = Components.utils; |
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8 |
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9 this.EXPORTED_SYMBOLS = ["TelemetryStopwatch"]; |
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10 |
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11 let Telemetry = Cc["@mozilla.org/base/telemetry;1"] |
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12 .getService(Ci.nsITelemetry); |
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13 |
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14 // simpleTimers are directly associated with a histogram |
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15 // name. objectTimers are associated with an object _and_ |
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16 // a histogram name. |
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17 let simpleTimers = {}; |
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18 let objectTimers = new WeakMap(); |
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19 |
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20 this.TelemetryStopwatch = { |
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21 /** |
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22 * Starts a timer associated with a telemetry histogram. The timer can be |
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23 * directly associated with a histogram, or with a pair of a histogram and |
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24 * an object. |
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25 * |
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26 * @param aHistogram a string which must be a valid histogram name |
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27 * from TelemetryHistograms.h |
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28 * |
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29 * @param aObj Optional parameter. If specified, the timer is associated |
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30 * with this object, meaning that multiple timers for a same |
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31 * histogram may be run concurrently, as long as they are |
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32 * associated with different objects. |
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33 * |
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34 * @return true if the timer was successfully started, false otherwise. If a |
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35 * timer already exists, it can't be started again, and the existing |
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36 * one will be cleared in order to avoid measurements errors. |
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37 */ |
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38 start: function(aHistogram, aObj) { |
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39 if (!validTypes(aHistogram, aObj)) |
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40 return false; |
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41 |
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42 let timers; |
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43 if (aObj) { |
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44 timers = objectTimers.get(aObj, {}); |
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45 objectTimers.set(aObj, timers); |
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46 } else { |
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47 timers = simpleTimers; |
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48 } |
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49 |
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50 if (timers.hasOwnProperty(aHistogram)) { |
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51 delete timers[aHistogram]; |
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52 Cu.reportError("TelemetryStopwatch: key \"" + |
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53 aHistogram + "\" was already initialized"); |
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54 return false; |
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55 } |
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56 |
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57 timers[aHistogram] = Date.now(); |
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58 return true; |
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59 }, |
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60 |
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61 /** |
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62 * Deletes the timer associated with a telemetry histogram. The timer can be |
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63 * directly associated with a histogram, or with a pair of a histogram and |
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64 * an object. Important: Only use this method when a legitimate cancellation |
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65 * should be done. |
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66 * |
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67 * @param aHistogram a string which must be a valid histogram name |
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68 * from TelemetryHistograms.json |
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69 * |
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70 * @param aObj Optional parameter. If specified, the timer is associated |
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71 * with this object, meaning that multiple timers for a same |
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72 * histogram may be run concurrently, as long as they are |
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73 * associated with different objects. |
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74 * |
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75 * @return true if the timer exist and it was cleared, false otherwise. |
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76 */ |
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77 cancel: function ts_cancel(aHistogram, aObj) { |
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78 if (!validTypes(aHistogram, aObj)) |
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79 return false; |
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80 |
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81 let timers = aObj |
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82 ? objectTimers.get(aObj, {}) |
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83 : simpleTimers; |
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84 |
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85 if (timers.hasOwnProperty(aHistogram)) { |
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86 delete timers[aHistogram]; |
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87 return true; |
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88 } |
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89 |
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90 return false; |
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91 }, |
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92 |
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93 /** |
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94 * Stops the timer associated with the given histogram (and object), |
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95 * calculates the time delta between start and finish, and adds the value |
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96 * to the histogram. |
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97 * |
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98 * @param aHistogram a string which must be a valid histogram name |
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99 * from TelemetryHistograms.h. If an invalid name |
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100 * is given, the function will throw. |
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101 * |
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102 * @param aObj Optional parameter which associates the histogram timer with |
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103 * the given object. |
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104 * |
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105 * @return true if the timer was succesfully stopped and the data was |
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106 * added to the histogram, false otherwise. |
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107 */ |
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108 finish: function(aHistogram, aObj) { |
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109 if (!validTypes(aHistogram, aObj)) |
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110 return false; |
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111 |
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112 let timers = aObj |
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113 ? objectTimers.get(aObj, {}) |
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114 : simpleTimers; |
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115 |
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116 let start = timers[aHistogram]; |
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117 delete timers[aHistogram]; |
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118 |
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119 if (start) { |
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120 let delta = Date.now() - start; |
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121 let histogram = Telemetry.getHistogramById(aHistogram); |
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122 histogram.add(delta); |
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123 return true; |
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124 } |
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125 |
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126 return false; |
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127 } |
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128 } |
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129 |
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130 function validTypes(aKey, aObj) { |
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131 return (typeof aKey == "string") && |
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132 (aObj === undefined || typeof aObj == "object"); |
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133 } |