import type { CacheAdapter } from '../cache/adapters.js';
import type { NodeCacheEntry, NodeCachePolicy } from '../types/graph.js';
/** @internal */
export declare class NodeCache {
    private readonly graphName;
    private readonly graphStore;
    private readonly clock;
    /** Created the first time a caching node has no store of its own, and not before. */
    private fallback;
    constructor(graphName: string, graphStore: CacheAdapter<NodeCacheEntry> | undefined, clock: () => number);
    /** The key for one task, or `undefined` when its state cannot be keyed safely. */
    key(policy: NodeCachePolicy, node: string, state: unknown, input: unknown): string | undefined;
    read(policy: NodeCachePolicy, key: string): Promise<NodeCacheEntry | undefined>;
    write(policy: NodeCachePolicy, key: string, entry: NodeCacheEntry): Promise<void>;
    private store;
}