/**
 * HTTP Cache Header parsing and utilities
 * Implements RFC 7234 (HTTP Caching)
 */
import type { ICacheMetadata } from '../webrequest.types.js';
/**
 * Parse Cache-Control header into metadata
 */
export declare function parseCacheControl(cacheControlHeader: string | null): Partial<ICacheMetadata>;
/**
 * Parse Expires header into timestamp
 */
export declare function parseExpires(expiresHeader: string | null): number | undefined;
/**
 * Extract cache metadata from response headers
 */
export declare function extractCacheMetadata(headers: Headers): ICacheMetadata;
/**
 * Check if a cached response is still fresh
 */
export declare function isFresh(cacheEntry: {
    timestamp: number;
    maxAge?: number;
}, metadata: ICacheMetadata): boolean;
/**
 * Check if revalidation is required
 */
export declare function requiresRevalidation(metadata: ICacheMetadata): boolean;
/**
 * Create conditional request headers for revalidation
 */
export declare function createConditionalHeaders(cacheEntry: {
    etag?: string;
    lastModified?: string;
}): HeadersInit;
/**
 * Convert Headers object to plain object for storage
 */
export declare function headersToObject(headers: Headers): Record<string, string>;
/**
 * Convert plain object back to Headers
 */
export declare function objectToHeaders(obj: Record<string, string>): Headers;