120 lines
3.7 KiB
JavaScript
120 lines
3.7 KiB
JavaScript
const cleanPeriod = 60*1000;//1 минута
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const cleanTimeout = 60;//timeout в минутах (cleanPeriod)
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class LimitedQueue {
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constructor(enqueueAfter = 10, size = 100, timeout = cleanTimeout) {//timeout в минутах (cleanPeriod)
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this.size = size;
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this.timeout = timeout;
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this.freed = enqueueAfter;
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this.listeners = [];
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this.timer = setTimeout(() => { this.periodicClean(); }, cleanPeriod);
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}
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_addListener(listener) {
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this.listeners.push(Object.assign({regTime: Date.now()}, listener));
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}
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//отсылаем сообщение первому ожидающему и удаляем его из списка
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_emitFree() {
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if (this.listeners.length > 0) {
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let listener = this.listeners.shift();
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listener.onFree();
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const now = Date.now();
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for (let i = 0; i < this.listeners.length; i++) {
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listener = this.listeners[i];
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listener.regTime = now;
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listener.onPlaceChange(i + 1);
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}
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}
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}
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get(onPlaceChange) {
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return new Promise((resolve, reject) => {
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if (this.destroyed)
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reject('destroyed');
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const take = () => {
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if (this.freed <= 0)
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throw new Error('Ошибка получения ресурсов в очереди ожидания');
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this.freed--;
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let returned = false;
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return {
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ret: () => {
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if (!returned) {
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this.freed++;
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this._emitFree();
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returned = true;
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}
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}
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};
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};
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if (this.freed > 0) {
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resolve(take());
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} else {
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if (this.listeners.length < this.size) {
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this._addListener({
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onFree: () => {
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resolve(take());
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},
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onError: (err) => {
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reject(err);
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},
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onPlaceChange: (i) => {
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if (onPlaceChange)
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onPlaceChange(i);
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}
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});
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if (onPlaceChange)
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onPlaceChange(this.listeners.length);
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} else {
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reject('Превышен размер очереди ожидания');
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}
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}
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});
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}
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destroy() {
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if (this.timer) {
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clearTimeout(this.timer);
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this.timer = null;
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}
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for (const listener of this.listeners) {
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listener.onError('destroy');
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}
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this.listeners = [];
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this.destroyed = true;
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}
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periodicClean() {
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try {
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this.timer = null;
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const now = Date.now();
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//чистка listeners, убираем зависшие в очереди на одном месте
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let newListeners = [];
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for (const listener of this.listeners) {
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if (now - listener.regTime < this.timeout*cleanPeriod - 50) {
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newListeners.push(listener);
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} else {
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listener.onError('Время ожидания в очереди истекло');
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}
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}
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this.listeners = newListeners;
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} finally {
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if (!this.destroyed) {
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this.timer = setTimeout(() => { this.periodicClean(); }, cleanPeriod);
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}
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}
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}
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}
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module.exports = LimitedQueue; |