174 lines
2.9 KiB
JavaScript
174 lines
2.9 KiB
JavaScript
/**
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* Module dependencies.
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*/
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try {
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var EventEmitter = require('events').EventEmitter;
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if (!EventEmitter) throw new Error();
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} catch (err) {
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var Emitter = require('emitter');
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}
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/**
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* Defer.
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*/
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var defer = typeof process !== 'undefined' && process && typeof process.nextTick === 'function'
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? process.nextTick
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: function(fn){ setTimeout(fn); };
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/**
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* Noop.
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*/
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function noop(){}
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/**
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* Expose `Batch`.
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*/
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module.exports = Batch;
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/**
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* Create a new Batch.
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*/
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function Batch() {
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if (!(this instanceof Batch)) return new Batch;
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this.fns = [];
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this.concurrency(Infinity);
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this.throws(true);
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for (var i = 0, len = arguments.length; i < len; ++i) {
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this.push(arguments[i]);
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}
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}
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/**
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* Inherit from `EventEmitter.prototype`.
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*/
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if (EventEmitter) {
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Batch.prototype.__proto__ = EventEmitter.prototype;
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} else {
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Emitter(Batch.prototype);
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}
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/**
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* Set concurrency to `n`.
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*
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* @param {Number} n
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* @return {Batch}
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* @api public
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*/
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Batch.prototype.concurrency = function(n){
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this.n = n;
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return this;
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};
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/**
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* Queue a function.
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*
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* @param {Function} fn
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* @return {Batch}
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* @api public
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*/
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Batch.prototype.push = function(fn){
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this.fns.push(fn);
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return this;
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};
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/**
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* Set wether Batch will or will not throw up.
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*
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* @param {Boolean} throws
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* @return {Batch}
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* @api public
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*/
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Batch.prototype.throws = function(throws) {
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this.e = !!throws;
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return this;
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};
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/**
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* Execute all queued functions in parallel,
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* executing `cb(err, results)`.
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*
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* @param {Function} cb
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* @return {Batch}
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* @api public
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*/
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Batch.prototype.end = function(cb){
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var self = this
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, total = this.fns.length
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, pending = total
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, results = []
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, errors = []
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, cb = cb || noop
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, fns = this.fns
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, max = this.n
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, throws = this.e
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, index = 0
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, done;
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// empty
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if (!fns.length) return defer(function(){
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cb(null, results);
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});
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// process
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function next() {
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var i = index++;
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var fn = fns[i];
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if (!fn) return;
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var start = new Date;
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try {
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fn(callback);
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} catch (err) {
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callback(err);
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}
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function callback(err, res){
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if (done) return;
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if (err && throws) return done = true, defer(function(){
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cb(err);
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});
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var complete = total - pending + 1;
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var end = new Date;
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results[i] = res;
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errors[i] = err;
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self.emit('progress', {
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index: i,
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value: res,
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error: err,
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pending: pending,
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total: total,
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complete: complete,
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percent: complete / total * 100 | 0,
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start: start,
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end: end,
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duration: end - start
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});
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if (--pending) next();
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else defer(function(){
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if(!throws) cb(errors, results);
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else cb(null, results);
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});
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}
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}
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// concurrency
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for (var i = 0; i < fns.length; i++) {
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if (i == max) break;
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next();
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}
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return this;
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};
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