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Bug 518146 - Generate shorter GUIDs than nsIUUIDGenerator

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Randomly generate 10 characters from a pool of 70 possible characters for an equivalent 61.29-bit GUID which should have around 1% chance of collision (within a collection) after ~100 million records.
This commit is contained in:
Edward Lee 2009-09-24 15:54:47 -07:00
parent 442f5ac9d3
commit 13ec4c4921
1 changed files with 22 additions and 3 deletions
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25
services/sync/modules/util.js
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@ -149,9 +149,28 @@ let Utils = {
// Generates a brand-new globally unique identifier (GUID).
makeGUID: function makeGUID() {
let uuidgen = Cc["@mozilla.org/uuid-generator;1"].
getService(Ci.nsIUUIDGenerator);
return uuidgen.generateUUID().toString().replace(/[{}]/g, '');
// 70 characters that are not-escaped URL-friendly
const code =
"!()*-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz~";
let guid = "";
let num = 0;
let val;
// Generate ten 70-value characters for a 70^10 (~61.29-bit) GUID
for (let i = 0; i < 10; i++) {
// Refresh the number source after using it a few times
if (i == 0 || i == 5)
num = Math.random();
// Figure out which code to use for the next GUID character
num *= 70;
val = Math.floor(num);
guid += code[val];
num -= val;
}
return guid;
},
anno: function anno(id, anno, val, expire) {