File

util/throttle.lua @ 13146:771eb453e03a

util.sqlite3: Deduplicate query methods There were 3 very similar methods: - :execute() - :execute_query() - :execute_update() The first one returns the prepared statement and is mainly used internally in the library for CREATE statements. The later two only really differ in how the results are returned. Those two are one main method and one small one that only picks out the iterator.
author Kim Alvefur <zash@zash.se>
date Sat, 10 Jun 2023 22:02:15 +0200
parent 12975:d10957394a3c
line wrap: on
line source


local gettime = require "prosody.util.time".now
local setmetatable = setmetatable;

local _ENV = nil;
-- luacheck: std none

local throttle = {};
local throttle_mt = { __index = throttle };

function throttle:update()
	local newt = gettime();
	local elapsed = newt - self.t;
	self.t = newt;
	local balance = (self.rate * elapsed) + self.balance;
	if balance > self.max then
		self.balance = self.max;
	else
		self.balance = balance;
	end
	return self.balance;
end

function throttle:peek(cost)
	cost = cost or 1;
	return self.balance >= cost or self:update() >= cost;
end

function throttle:poll(cost, split)
	if self:peek(cost) then
		self.balance = self.balance - cost;
		return true;
	else
		local balance = self.balance;
		if split then
			self.balance = 0;
		end
		return false, balance, (cost-balance);
	end
end

local function create(max, period)
	return setmetatable({ rate = max / period, max = max, t = gettime(), balance = max }, throttle_mt);
end

return {
	create = create;
};