whale-plus/lib/upload-sdk/src/upload-core/TaskQueue.js

A Component Library for Vue 3

'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var EventEmitter = require('./EventEmitter.js');

class Task {
  constructor(fn, payload) {
    this.fn = fn;
    this.payload = payload;
  }
  run() {
    return this.fn(this.payload);
  }
}
class TaskQueue extends EventEmitter.EventEmitter {
  constructor(concurrency = 4) {
    super();
    this.tasks = /* @__PURE__ */ new Set();
    this.currentCount = 0;
    this.status = "paused";
    this.concurrency = 4;
    this.concurrency = concurrency;
  }
  add(...tasks) {
    for (const t of tasks) {
      this.tasks.add(t);
    }
  }
  addAndStart(...tasks) {
    this.add(...tasks);
    this.start();
  }
  start() {
    if (this.status === "running") {
      return;
    }
    if (this.tasks.size === 0) {
      this.emit("drain");
      return;
    }
    this.status = "running";
    this.emit("start");
    this.runNext();
  }
  takeHeadTask() {
    const task = this.tasks.values().next().value;
    if (task) {
      this.tasks.delete(task);
    }
    return task;
  }
  runNext() {
    if (this.status !== "running") {
      return;
    }
    if (this.currentCount >= this.concurrency) {
      return;
    }
    const task = this.takeHeadTask();
    if (!task) {
      this.status = "paused";
      this.emit("drain");
      return;
    }
    this.currentCount++;
    Promise.resolve(task.run()).finally(() => {
      this.currentCount--;
      this.runNext();
    });
  }
  pause() {
    this.status = "paused";
    this.emit("pause");
  }
}

exports.Task = Task;
exports.TaskQueue = TaskQueue;
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