json-crdt-server/lib/util/Mutex.js

JSON CRDT server and syncing local-first browser client

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Mutex = void 0;
const Defer_1 = require("thingies/lib/Defer");
class Entry {
    constructor(code, future) {
        this.code = code;
        this.future = future;
    }
}
class Mutex {
    constructor() {
        this.queue = new Map();
        this.acquire = async (key, code) => {
            const queue = this.queue.get(key);
            const entry = new Entry(code, new Defer_1.Defer());
            if (queue instanceof Array)
                queue.push(entry);
            else {
                this.queue.set(key, []);
                this.run(key, entry).catch(() => { });
            }
            return await entry.future.promise;
        };
    }
    async run(key, entry) {
        try {
            const result = await entry.code();
            entry.future.resolve(result);
        }
        catch (error) {
            entry.future.reject(error);
        }
        finally {
            const queue = this.queue;
            const entries = queue.get(key);
            if (entries instanceof Array) {
                if (!entries.length)
                    queue.delete(key);
                else {
                    const next = entries.shift();
                    if (next instanceof Entry)
                        this.run(key, next).catch(() => { });
                }
            }
        }
    }
}
exports.Mutex = Mutex;