prosody
3f526f84dbbd
util/throttle.lua

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util/throttle.lua @ 4747:3f526f84dbbd

moduleapi: Remove unused variable 'module_items'
author Matthew Wild <mwild1@gmail.com>
date Sat, 28 Apr 2012 02:24:41 +0100
parent 4467:fc8a22936b3c
child 4952:0e9a5b63206a
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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
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5 module "throttle"
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7 local throttle = {};
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8 local throttle_mt = { __index = throttle };
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10 function throttle:update()
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11 local newt = gettime();
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12 local elapsed = newt - self.t;
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13 self.t = newt;
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14 local balance = self.rate * elapsed + self.balance;
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15 if balance > self.max then
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16 self.balance = self.max;
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17 else
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18 self.balance = balance;
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19 end
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20 return self.balance;
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21 end
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23 function throttle:peek(cost)
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24 cost = cost or 1;
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25 return self.balance >= cost or self:update() >= cost;
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26 end
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28 function throttle:poll(cost, split)
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29 if self:peek(cost) then
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30 self.balance = self.balance - cost;
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31 return true;
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32 else
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33 local balance = self.balance;
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34 if split then
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35 self.balance = 0;
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36 end
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fc8a22936b3c util.throttle: Fix 'outstanding' return value
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37 return false, balance, (cost-balance);
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38 end
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39 end
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41 function create(max, period)
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42 return setmetatable({ rate = max / period, max = max, t = 0, balance = max }, throttle_mt);
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43 end
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44
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45 return _M;