prosody
cfeb0077c9e9
util/throttle.lua

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util/throttle.lua @ 10571:cfeb0077c9e9

net.server_epoll: Avoid concatenating buffer with single item Saves creating a string that'll be identical to buffer[1] anyways, as well as a C function call. Depending on Lua version and length of the string, this could be reusing an interned string, but a longer one would probably be duplicated for no reason. Having exactly one item in the buffer seems like it would be fairly common, but I have not done an extensive study. If opportunistic writes are enabled then it will be even more likely. This special case could be optimized like this in table.concat but it does not look like it is.
author Kim Alvefur <zash@zash.se>
date Sat, 28 Dec 2019 06:18:58 +0100
parent 8555:4f0f5b49bb03
child 12975:d10957394a3c
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851885cb332d util.throttle: Generic module by waqas to limit something over some time
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1
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2 local gettime = require "util.time".now
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3 local setmetatable = setmetatable;
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5 local _ENV = nil;
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6 -- luacheck: std none
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8 local throttle = {};
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9 local throttle_mt = { __index = throttle };
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11 function throttle:update()
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12 local newt = gettime();
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13 local elapsed = newt - self.t;
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14 self.t = newt;
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15 local balance = (self.rate * elapsed) + self.balance;
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16 if balance > self.max then
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17 self.balance = self.max;
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18 else
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19 self.balance = balance;
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20 end
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21 return self.balance;
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22 end
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24 function throttle:peek(cost)
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25 cost = cost or 1;
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26 return self.balance >= cost or self:update() >= cost;
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27 end
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29 function throttle:poll(cost, split)
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30 if self:peek(cost) then
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31 self.balance = self.balance - cost;
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32 return true;
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33 else
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34 local balance = self.balance;
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35 if split then
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36 self.balance = 0;
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37 end
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38 return false, balance, (cost-balance);
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39 end
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40 end
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42 local function create(max, period)
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43 return setmetatable({ rate = max / period, max = max, t = gettime(), balance = max }, throttle_mt);
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44 end
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46 return {
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47 create = create;
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48 };