File

util/presence.lua @ 11661:735b8f4a6d7e

net.http: Send entire HTTP request header as one write When opportunistic writes are enabled this reduces the number of syscalls and TCP packets sent on the wire. Experiments with TCP Fast Open made this even more obvious. That table trick probably wasn't as efficient. Lua generates bytecode for a table with zero array slots and space for two entries in the hash part, plus code to set [2] and [4]. I didn't verify but I suspect it would have had to resize the table when setting [1] and [3], although probably only once. Concatenating the strings directly in Lua is easier to read and involves no extra table or function call.
author Kim Alvefur <zash@zash.se>
date Thu, 08 Jul 2021 18:21:59 +0200
parent 8885:d4f5d47f874d
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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 t_insert = table.insert;

local function select_top_resources(user)
	local priority = 0;
	local recipients = {};
	for _, session in pairs(user.sessions) do -- find resource with greatest priority
		if session.presence then
			local p = session.priority;
			if p > priority then
				priority = p;
				recipients = {session};
			elseif p == priority then
				t_insert(recipients, session);
			end
		end
	end
	return recipients;
end
local function recalc_resource_map(user)
	if user then
		user.top_resources = select_top_resources(user);
		if #user.top_resources == 0 then user.top_resources = nil; end
	end
end

return {
	select_top_resources = select_top_resources;
	recalc_resource_map = recalc_resource_map;
}