36 lines
670 B
JavaScript
36 lines
670 B
JavaScript
import { Queue } from './queue.mjs';
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export class AsyncLock {
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constructor() {
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this.pending_queue = new Queue();
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this.state = false;
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this.lock_id = 0;
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}
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query() {
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return this.state;
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}
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acquire() {
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if (!this.state) {
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this.state = true;
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this.lock_id += 1;
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return Promise.resolve(this.lock_id);
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}
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return new Promise((resolve, _reject) => this.pending_queue.push(resolve));
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}
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release(lock_id) {
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if (lock_id != this.lock_id) { return; }
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if (this.pending_queue.empty()) {
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this.state = false;
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return;
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}
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let resolve = this.pending_queue.front();
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this.pending_queue.popFront();
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this.lock_id += 1;
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resolve(this.lock_id);
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}
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};
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