51 lines
1.5 KiB
TypeScript
51 lines
1.5 KiB
TypeScript
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const THREAD_ID = `${Math.floor(Math.random() * 1000)}-${Date.now()}`;
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const setItem = egret.localStorage.setItem.bind(localStorage);
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const getItem = egret.localStorage.getItem.bind(localStorage);
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const removeItem = egret.localStorage.removeItem.bind(localStorage);
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const nextTick = fn => {
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setTimeout(fn, 0);
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};
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/**
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* 利用共享区域实现快速锁
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*/
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class LockUtils {
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private _keyX: string;
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private _keyY: string;
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constructor(key){
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this._keyX = `mutex_key_${key}_X`;
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this._keyY = `mutex_key_${key}_Y`;
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}
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public lock(){
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return new Promise((resolve, reject) => {
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const fn = () => {
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setItem(this._keyX, THREAD_ID);
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if (!getItem(this._keyY) === null){
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// restart
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nextTick(fn);
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}
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setItem(this._keyY, THREAD_ID);
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if (getItem(this._keyX) !== THREAD_ID){
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// delay
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setTimeout(()=>{
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if (getItem(this._keyY) !== THREAD_ID){
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// restart
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nextTick(fn);
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return;
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}
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// critical section
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resolve();
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removeItem(this._keyY);
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}, 10);
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} else {
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resolve();
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removeItem(this._keyY);
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}
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};
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fn();
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});
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}
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}
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