mirror of https://github.com/webpack/webpack.git
42 lines
706 B
JavaScript
42 lines
706 B
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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class Semaphore {
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constructor(available) {
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this.available = available;
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this.waiters = [];
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this._continue = this._continue.bind(this);
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}
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acquire(callback) {
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if (this.available > 0) {
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this.available--;
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callback();
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} else {
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this.waiters.push(callback);
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}
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}
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release() {
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this.available++;
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if (this.waiters.length > 0) {
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process.nextTick(this._continue);
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}
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}
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_continue() {
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if (this.available > 0) {
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if (this.waiters.length > 0) {
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this.available--;
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const callback = this.waiters.pop();
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callback();
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}
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}
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}
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}
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module.exports = Semaphore;
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