aaac7fed
 liuqimichale
add
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'use strict';
function Queue(options) {
if (!(this instanceof Queue)) {
return new Queue(options);
}
options = options || {};
this.concurrency = options.concurrency || Infinity;
this.pending = 0;
this.jobs = [];
this.cbs = [];
this._done = done.bind(this);
}
var arrayAddMethods = [
'push',
'unshift',
'splice'
];
arrayAddMethods.forEach(function(method) {
Queue.prototype[method] = function() {
var methodResult = Array.prototype[method].apply(this.jobs, arguments);
this._run();
return methodResult;
};
});
Object.defineProperty(Queue.prototype, 'length', {
get: function() {
return this.pending + this.jobs.length;
}
});
Queue.prototype._run = function() {
if (this.pending === this.concurrency) {
return;
}
if (this.jobs.length) {
var job = this.jobs.shift();
this.pending++;
job(this._done);
this._run();
}
if (this.pending === 0) {
while (this.cbs.length !== 0) {
var cb = this.cbs.pop();
process.nextTick(cb);
}
}
};
Queue.prototype.onDone = function(cb) {
if (typeof cb === 'function') {
this.cbs.push(cb);
this._run();
}
};
function done() {
this.pending--;
this._run();
}
module.exports = Queue;
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