124 lines
2.0 KiB
JavaScript
124 lines
2.0 KiB
JavaScript
'use strict';
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class QuickLRU {
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constructor(options = {}) {
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if (!(options.maxSize && options.maxSize > 0)) {
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throw new TypeError('`maxSize` must be a number greater than 0');
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}
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this.maxSize = options.maxSize;
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this.onEviction = options.onEviction;
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this.cache = new Map();
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this.oldCache = new Map();
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this._size = 0;
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}
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_set(key, value) {
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this.cache.set(key, value);
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this._size++;
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if (this._size >= this.maxSize) {
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this._size = 0;
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if (typeof this.onEviction === 'function') {
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for (const [key, value] of this.oldCache.entries()) {
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this.onEviction(key, value);
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}
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}
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this.oldCache = this.cache;
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this.cache = new Map();
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}
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}
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get(key) {
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if (this.cache.has(key)) {
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return this.cache.get(key);
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}
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if (this.oldCache.has(key)) {
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const value = this.oldCache.get(key);
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this.oldCache.delete(key);
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this._set(key, value);
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return value;
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}
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}
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set(key, value) {
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if (this.cache.has(key)) {
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this.cache.set(key, value);
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} else {
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this._set(key, value);
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}
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return this;
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}
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has(key) {
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return this.cache.has(key) || this.oldCache.has(key);
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}
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peek(key) {
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if (this.cache.has(key)) {
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return this.cache.get(key);
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}
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if (this.oldCache.has(key)) {
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return this.oldCache.get(key);
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}
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}
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delete(key) {
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const deleted = this.cache.delete(key);
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if (deleted) {
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this._size--;
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}
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return this.oldCache.delete(key) || deleted;
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}
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clear() {
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this.cache.clear();
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this.oldCache.clear();
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this._size = 0;
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}
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* keys() {
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for (const [key] of this) {
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yield key;
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}
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}
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* values() {
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for (const [, value] of this) {
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yield value;
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}
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}
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* [Symbol.iterator]() {
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for (const item of this.cache) {
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yield item;
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}
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for (const item of this.oldCache) {
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const [key] = item;
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if (!this.cache.has(key)) {
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yield item;
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}
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}
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}
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get size() {
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let oldCacheSize = 0;
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for (const key of this.oldCache.keys()) {
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if (!this.cache.has(key)) {
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oldCacheSize++;
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}
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}
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return Math.min(this._size + oldCacheSize, this.maxSize);
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}
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}
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module.exports = QuickLRU;
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