import type { FsCache } from "./cache.js";
export interface InMemoryFsCacheOptions {
    /** Maximum total payload size in bytes. Older entries are evicted in LRU order when exceeded. Default: 64 MiB. */
    maxBytes?: number;
}
/**
 * In-process LRU cache with a byte budget. Insertion order in the underlying
 * `Map` is the LRU ordering: a successful `get` re-inserts the entry to mark
 * it as most-recently-used. Eviction walks the iterator from the front (the
 * least-recently-used end) until the byte budget is satisfied.
 *
 * Single-process only. Sharing one instance across `PgFileSystem` instances
 * for the same workspace is safe; sharing across processes is not — use a
 * Redis adapter for that.
 */
export declare class InMemoryFsCache implements FsCache {
    private readonly store;
    private readonly maxBytes;
    private currentBytes;
    constructor(options?: InMemoryFsCacheOptions);
    get(key: string): Promise<Uint8Array | null>;
    set(key: string, value: Uint8Array, ttlMs?: number): Promise<void>;
    delete(keys: string[]): Promise<void>;
    clear(prefix: string): Promise<void>;
    /** Total bytes currently stored. Exposed for diagnostics and tests. */
    get sizeBytes(): number;
    /** Number of entries currently stored. Exposed for diagnostics and tests. */
    get size(): number;
}
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