| 1 | ;
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| 2 |
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| 3 | class Mutex {
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| 4 | constructor() {
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| 5 | this._locked = false;
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| 6 | this._queue = [];
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| 7 | }
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| 8 |
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| 9 | lock(fn) {
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| 10 | if (this._locked) {
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| 11 | this._queue.push(fn);
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| 12 | return;
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| 13 | }
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| 14 |
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| 15 | this._locked = true;
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| 16 | fn();
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| 17 | }
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| 18 |
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| 19 | unlock() {
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| 20 | if (!this._locked) return;
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| 21 |
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| 22 | const next = this._queue.shift();
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| 23 |
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| 24 | if (next) {
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| 25 | next();
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| 26 | } else {
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| 27 | this._locked = false;
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| 28 | }
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| 29 | }
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| 30 | }
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| 31 |
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| 32 | module.exports = Mutex;
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