tav-media/lib/src/utils/dispatcher.js

Cross platform media editing framework

var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
/**
 * 异步任务调度器
 * @ignore
 * @internal
 */
export class Dispatcher {
    constructor() {
        this.taskInQueue = Promise.resolve(1);
        this.uniqueTaskCancelTokens = {};
        this.tasks = [];
        this.id = 0;
        this.waitForNextTask = null;
        this.run();
    }
    run() {
        return __awaiter(this, void 0, void 0, function* () {
            while (true) {
                const task = this.tasks.shift();
                if (!task) {
                    yield new Promise((resolve) => {
                        this.waitForNextTask = resolve;
                    });
                    continue;
                }
                yield task();
            }
        });
    }
    /**
     * 设定超时
     * @param time 超时时间 ms
     */
    delay(time, cb) {
        return new Promise((resolve) => setTimeout(() => {
            cb();
            resolve(undefined);
        }, time));
    }
    /**
     * 将任务加入队列，相同 uniqueId 的任务会被替换
     * @param task 任务函数
     * @param uniqueId 任务唯一标识，用于取消前置相同 uniqueId 的任务
     */
    queue(task, uniqueId, timeout = 500) {
        const id = this.id++;
        const printTaskLog = false;
        let cancelToken = null;
        if (uniqueId) {
            if (this.uniqueTaskCancelTokens[uniqueId]) {
                this.uniqueTaskCancelTokens[uniqueId].cancel = true;
            }
            // 此处不能加 else, 每个任务应该有自己的 cancel token
            // 否则可能会导致后置任务被取消
            cancelToken = { cancel: false };
            this.uniqueTaskCancelTokens[uniqueId] = cancelToken;
        }
        printTaskLog && console.log("task start", uniqueId, id);
        return new Promise((res, rej) => {
            const next = () => __awaiter(this, void 0, void 0, function* () {
                if (cancelToken === null || cancelToken === void 0 ? void 0 : cancelToken.cancel) {
                    printTaskLog && console.log("task cancel", uniqueId, id);
                    return res(undefined);
                }
                let resolved = false;
                const queued = Promise.race([
                    (() => __awaiter(this, void 0, void 0, function* () {
                        // wait for native calls
                        // await tav.webAssemblyQueue.exec(() => { }, null);
                        printTaskLog && console.log("task run", uniqueId, id);
                        const rt = yield task();
                        resolved = true;
                        printTaskLog && console.log("task end", uniqueId, id);
                        res(rt);
                    }))(),
                    this.delay(timeout, () => {
                        if (!resolved) {
                            printTaskLog && console.log("task timeout", uniqueId, id);
                        }
                        res(undefined);
                    }),
                ]);
                return queued;
            });
            this.tasks.push(next);
            this.waitForNextTask && this.waitForNextTask();
        });
    }
}