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authorruki <waruqi@gmail.com>2018-11-08 00:38:48 +0800
committerruki <waruqi@gmail.com>2018-11-07 21:53:09 +0800
commit26105034da4fcce7ac883c899d781f016559310d (patch)
treec459a5dc4e3aa0972d9919033ece511ce76dd129 /node_modules/webpack/lib/util/Semaphore.js
parent2c77f00f1a7ecb6c8192f9c16d3b2001b254a107 (diff)
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diff --git a/node_modules/webpack/lib/util/Semaphore.js b/node_modules/webpack/lib/util/Semaphore.js
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+/*
+ MIT License http://www.opensource.org/licenses/mit-license.php
+ Author Tobias Koppers @sokra
+*/
+"use strict";
+
+class Semaphore {
+ /**
+ * Creates an instance of Semaphore.
+ *
+ * @param {number} available the amount available number of "tasks"
+ * in the Semaphore
+ */
+ constructor(available) {
+ this.available = available;
+ /** @type {(function(): void)[]} */
+ this.waiters = [];
+ /** @private */
+ this._continue = this._continue.bind(this);
+ }
+
+ /**
+ * @param {function(): void} callback function block to capture and run
+ * @returns {void}
+ */
+ acquire(callback) {
+ if (this.available > 0) {
+ this.available--;
+ callback();
+ } else {
+ this.waiters.push(callback);
+ }
+ }
+
+ release() {
+ this.available++;
+ if (this.waiters.length > 0) {
+ process.nextTick(this._continue);
+ }
+ }
+
+ _continue() {
+ if (this.available > 0) {
+ if (this.waiters.length > 0) {
+ this.available--;
+ const callback = this.waiters.pop();
+ callback();
+ }
+ }
+ }
+}
+
+module.exports = Semaphore;