@thermopylae/lib.cache/dist/policies/eviction/lfu-base.js

Modular cache.

import { createException } from "../../error.js";
import { OrderedBucketList } from "../../data-structures/bucket-list/ordered-bucket-list.js";
const IGNORED_BUCKET_ID = -1;
class BaseLFUEvictionPolicy {
    frequencies;
    cacheMaxCapacity;
    cacheBackendElementsCount;
    deleteFromCache;
    constructor(cacheMaxCapacity, cacheBackendElementsCount) {
        if (cacheMaxCapacity <= 0) {
            throw createException("INVALID_CACHE_MAX_CAPACITY" , `Capacity needs to be greater than 0. Given: ${cacheMaxCapacity}.`);
        }
        this.cacheMaxCapacity = cacheMaxCapacity;
        this.cacheBackendElementsCount = cacheBackendElementsCount;
        this.frequencies = new OrderedBucketList();
    }
    get size() {
        return this.frequencies.size;
    }
    onHit(entry) {
        const oldFrequency = OrderedBucketList.getBucketId(entry);
        const newFrequency = this.computeEntryFrequency(entry, oldFrequency);
        this.frequencies.move(IGNORED_BUCKET_ID, newFrequency, entry);
        return 1 ;
    }
    onMiss() {
        return undefined;
    }
    onSet(entry) {
        if (this.cacheBackendElementsCount.size > this.cacheMaxCapacity) {
            this.evict();
        }
        this.frequencies.add(this.initialFrequency, entry);
    }
    onUpdate(_entry) {
        return undefined;
    }
    onDelete(entry) {
        this.frequencies.remove(IGNORED_BUCKET_ID, entry);
    }
    onClear() {
        this.frequencies.clear();
    }
    setDeleter(deleter) {
        this.deleteFromCache = deleter;
    }
    evict() {
        const currentFreqListHead = this.frequencies.head;
        this.deleteFromCache(currentFreqListHead.bucket.tail);
        this.onEvict(currentFreqListHead.id);
    }
}
export { BaseLFUEvictionPolicy };