41 lines
1.2 KiB
JavaScript
41 lines
1.2 KiB
JavaScript
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function Queue() {
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let waitingQueue = this.waitingQueue = [];
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let isRunning = this.isRunning = false; // 记录是否有未完成的任务
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function execute(task, resolve, reject) {
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task()
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.then((data) => {
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resolve(data);
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})
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.catch((e) => {
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reject(e);
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})
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.finally(() => {
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// 等待任务队列中如果有任务，则触发它；否则设置isRunning = false,表示无任务状态
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if (waitingQueue.length) {
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const next = waitingQueue.shift();
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execute(next.task, next.resolve, next.reject);
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} else {
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isRunning = false;
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}
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});
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}
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this.exec = function(task) {
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return new Promise((resolve, reject) => {
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if (isRunning) {
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waitingQueue.push({
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task,
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resolve,
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reject
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});
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} else {
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isRunning = true;
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execute(task, resolve, reject);
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}
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});
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}
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}
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/* 队列实例，某些平台一起使用多个组件时需要通过队列逐一绘制，否则部分绘制方法异常，nvue端的iOS gcanvas尤其明显，在不通过队列绘制时会出现图片丢失的情况 */
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export const queueDraw = new Queue();
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export const queueLoadImage = new Queue();
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