tools/telemetry/third_party/webpagereplay/deterministic.js

   1 (function () {
   2   var random_count = 0;
   3   var random_count_threshold = 25;
   4   var random_seed = 0.462;
   5   Math.random = function() {
   6     random_count++;
   7     if (random_count > random_count_threshold){
   8      random_seed += 0.1;
   9      random_count = 1;
  10     }
  11     return (random_seed % 1);
  12   };
  13   if (typeof(crypto) == 'object' &&
  14       typeof(crypto.getRandomValues) == 'function') {
  15     crypto.getRandomValues = function(arr) {
  16       var scale = Math.pow(256, arr.BYTES_PER_ELEMENT);
  17       for (var i = 0; i < arr.length; i++) {
  18         arr[i] = Math.floor(Math.random() * scale);
  19       }
  20       return arr;
  21     };
  22   }
  23 })();
  24 (function () {
  25   var date_count = 0;
  26   var date_count_threshold = 25;
  27   var orig_date = Date;
  28   var time_seed = 1204251968254;
  29   Date = function() {
  30     if (this instanceof Date) {
  31       date_count++;
  32       if (date_count > date_count_threshold){
  33         time_seed += 50;
  34         date_count = 1;
  35       }
  36       switch (arguments.length) {
  37       case 0: return new orig_date(time_seed);
  38       case 1: return new orig_date(arguments[0]);
  39       default: return new orig_date(arguments[0], arguments[1],
  40          arguments.length >= 3 ? arguments[2] : 1,
  41          arguments.length >= 4 ? arguments[3] : 0,
  42          arguments.length >= 5 ? arguments[4] : 0,
  43          arguments.length >= 6 ? arguments[5] : 0,
  44          arguments.length >= 7 ? arguments[6] : 0);
  45       }
  46     }
  47     return new Date().toString();
  48   };
  49   Date.__proto__ = orig_date;
  50   Date.prototype = orig_date.prototype;
  51   Date.prototype.constructor = Date;
  52   orig_date.now = function() {
  53     return new Date().getTime();
  54   };
  55   orig_date.prototype.getTimezoneOffset = function() {
  56     var dst2010Start = 1268560800000;
  57     var dst2010End = 1289120400000;
  58     if (this.getTime() >= dst2010Start && this.getTime() < dst2010End)
  59       return 420;
  60     return 480;
  61   };
  62 })();