/// <reference types="node" />
import LRU = require("lru-cache");
import https = require("https");
import { Meta } from "./types";
declare type CachedMeta = {
    meta: Meta;
    etag?: string;
    timestamp: number;
};
export declare class Cache {
    agent: https.Agent;
    cache: LRU<string, CachedMeta | Promise<CachedMeta>>;
    logger: typeof console;
    registry: string;
    headers: Record<string, string>;
    fetchCount: number;
    pendingRefreshes: LRU<string, Promise<Meta>>;
    constructor({ maxSockets, cacheSize, logger, registry, headers, }?: {
        maxSockets?: number;
        cacheSize?: number;
        logger?: typeof console;
        registry?: string;
        headers?: Record<string, string>;
    });
    exists(qualified: string): Promise<boolean>;
    refreshMeta(qualified: string, etag?: string): Promise<null | CachedMeta>;
    getMeta(qualified: string, requestedVersion?: string): Promise<Meta>;
    export(): Promise<Record<string, any>>;
    import(data: Record<string, any>): void;
}
export {};