aaac7fed
 liuqimichale
add
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/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
class Semaphore {
constructor(available) {
this.available = available;
this.waiters = [];
}
acquire(callback) {
if(this.available > 0) {
this.available--;
callback();
} else {
this.waiters.push(callback);
}
}
release() {
if(this.waiters.length > 0) {
const callback = this.waiters.pop();
process.nextTick(callback);
} else {
this.available++;
}
}
}
module.exports = Semaphore;
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