prosody
9030b056bd4a
util/throttle.lua

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util/throttle.lua @ 6499:9030b056bd4a 0.9.7

Backout changeset 6e67c73f730c: not a major fix and it breaks interop with at least Isode M-Link, and possibly standards, while it's not clear it actually fixes the original problem either.
author Matthew Wild <mwild1@gmail.com>
date Fri, 24 Oct 2014 23:20:06 +0100
parent 4952:0e9a5b63206a
child 6777:5de6b93d0190
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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 "socket".gettime;
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3 local setmetatable = setmetatable;
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4 local floor = math.floor;
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6 module "throttle"
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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 = floor(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 function create(max, period)
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43 return setmetatable({ rate = max / period, max = max, t = 0, balance = max }, throttle_mt);
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44 end
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45
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46 return _M;