File

util/uuid.lua @ 9751:39ee70fbb009

mod_mam: Perform message expiry based on building an index by date For each day, store a set of users that have new messages. To expire messages, we collect the union of sets of users from dates that fall outside the cleanup range. The previous algoritm did not work well with many users, especially with the default settings.
author Kim Alvefur <zash@zash.se>
date Thu, 03 Jan 2019 17:25:43 +0100
parent 7078:ec17115e3721
child 12355:a0ff5c438e9d
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-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local random = require "util.random";
local random_bytes = random.bytes;
local hex = require "util.hex".to;
local m_ceil = math.ceil;

local function get_nibbles(n)
	return hex(random_bytes(m_ceil(n/2))):sub(1, n);
end

local function get_twobits()
	return ("%x"):format(random_bytes(1):byte() % 4 + 8);
end

local function generate()
	-- generate RFC 4122 complaint UUIDs (version 4 - random)
	return get_nibbles(8).."-"..get_nibbles(4).."-4"..get_nibbles(3).."-"..(get_twobits())..get_nibbles(3).."-"..get_nibbles(12);
end

return {
	get_nibbles=get_nibbles;
	generate = generate ;
	-- COMPAT
	seed = random.seed;
};