bugcore
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bugcore is a JavaScript library that provides a foundational architecture for object oriented JS
213 lines (169 loc) • 5.99 kB
JavaScript
/*
* Copyright (c) 2016 airbug Inc. http://airbug.com
*
* bugcore may be freely distributed under the MIT license.
*/
//-------------------------------------------------------------------------------
// Annotations
//-------------------------------------------------------------------------------
//@Export('RateLimiter')
//@Require('Class')
//@Require('Func')
//@Require('Obj')
//@Require('Queue')
//-------------------------------------------------------------------------------
// Context
//-------------------------------------------------------------------------------
require('bugpack').context("*", function(bugpack) {
//-------------------------------------------------------------------------------
// BugPack
//-------------------------------------------------------------------------------
var Class = bugpack.require('Class');
var Func = bugpack.require('Func');
var Obj = bugpack.require('Obj');
var Queue = bugpack.require('Queue');
//-------------------------------------------------------------------------------
// Declare Class
//-------------------------------------------------------------------------------
/**
* @class
* @extends {Obj}
*/
var RateLimiter = Class.extend(Obj, {
_name: "RateLimiter",
//-------------------------------------------------------------------------------
// Constructor
//-------------------------------------------------------------------------------
/**
* @constructs
* @param {number} permitsPerSecond
*/
_constructor: function(permitsPerSecond) {
this._super();
//-------------------------------------------------------------------------------
// Private Properties
//-------------------------------------------------------------------------------
/**
* @private
* @type {Queue.<function()>}
*/
this.acquisitionQueue = new Queue();
/**
* @private
* @type {number}
*/
this.lastAcqusitionTime = null;
/**
* @private
* @type {number}
*/
this.permitsPerSecond = permitsPerSecond;
/**
* @private
* @type {boolean}
*/
this.queueProcessingDelayed = false;
},
//-------------------------------------------------------------------------------
// Getters and Setters
//-------------------------------------------------------------------------------
/**
* @return {Queue.<function()>}
*/
getAcquisitionQueue: function() {
return this.acquisitionQueue;
},
/**
* @return {number}
*/
getLastAcquisitionTime: function() {
return this.lastAcqusitionTime;
},
/**
* @return {number}
*/
getPermitsPerSecond: function() {
return this.permitsPerSecond;
},
/**
* @param {number} permitsPerSecond
*/
setPermitsPerSecond: function(permitsPerSecond) {
this.permitsPerSecond = permitsPerSecond;
},
//-------------------------------------------------------------------------------
// Public Methods
//-------------------------------------------------------------------------------
/**
* @param {function()} method
*/
acquire: function(method) {
this.queueAcquisition(method);
this.tryProcessQueue();
},
//-------------------------------------------------------------------------------
// Private Methods
//-------------------------------------------------------------------------------
/**
* @private
*/
acquirePermit: function(method) {
this.lastAcqusitionTime = Date.now();
method();
},
/**
* @private
* @param {number} wait
*/
delayQueueProcessing: function(wait) {
if (!this.queueProcessingDelayed) {
this.queueProcessingDelayed = true;
Func.delayCall(this.delayQueueProcessingComplete, this, wait);
}
},
/**
* @private
*/
delayQueueProcessingComplete: function() {
this.queueProcessingDelayed = false;
this.tryProcessQueue();
},
/**
* @private
*/
processQueue: function() {
var method = this.acquisitionQueue.dequeue();
this.acquirePermit(method);
this.tryProcessQueue();
},
/**
* @private
* @param {function()} method
*/
queueAcquisition: function(method) {
this.acquisitionQueue.enqueue(method);
},
/**
* @private
*/
tryProcessQueue: function() {
if (!this.acquisitionQueue.isEmpty()) {
if (this.lastAcqusitionTime) {
var rate = 1000 / this.permitsPerSecond;
var elapsed = Date.now() - this.lastAcqusitionTime;
if (elapsed >= rate) {
this.processQueue();
} else {
this.delayQueueProcessing(rate - elapsed);
}
} else {
this.processQueue();
}
}
}
});
//-------------------------------------------------------------------------------
// Exports
//-------------------------------------------------------------------------------
bugpack.export('RateLimiter', RateLimiter);
});