import type { ExistsResult, ExistsOptions } from './npm.js';
interface PurlObject {
    name: string;
    namespace?: string | undefined;
    qualifiers?: Record<string, string> | undefined;
    subpath?: string | undefined;
    type?: string | undefined;
    version?: string | undefined;
}
/**
 * Check if a Cargo crate exists in crates.io.
 *
 * Queries crates.io at https://crates.io/api/v1/crates to verify crate
 * existence and optionally validate a specific version. Returns the max_version
 * from crate metadata.
 *
 * **Note:** crates.io requires a User-Agent header for API requests.
 *
 * **Caching:** Responses can be cached using a TTL cache to reduce registry
 * requests. Pass `{ cache }` option with a cache instance from `createTtlCache()`.
 *
 * @param name - Crate name (e.g., 'serde', 'tokio')
 * @param version - Optional version to validate (e.g., '1.0.152')
 * @param options - Optional configuration including cache
 * @returns Promise resolving to existence result with latest version
 *
 * @example
 * ```typescript
 * // Check if crate exists
 * const result = await cargoExists('serde')
 * // -> { exists: true, latestVersion: '1.0.197' }
 *
 * // Validate specific version
 * const result = await cargoExists('tokio', '1.35.0')
 * // -> { exists: true, latestVersion: '1.36.0' }
 *
 * // With caching
 * import { createTtlCache } from '@socketsecurity/lib/cache-with-ttl'
 * const cache = createTtlCache({ ttl: 5 * 60 * 1000, prefix: 'cargo' })
 * const result = await cargoExists('serde', undefined, { cache })
 *
 * // Non-existent crate
 * const result = await cargoExists('this-crate-does-not-exist')
 * // -> { exists: false, error: 'Crate not found' }
 * ```
 */
export declare function cargoExists(name: string, version?: string, options?: ExistsOptions): Promise<ExistsResult>;
/**
 * Validate Cargo package URL.
 * Cargo packages must not have a namespace. Name must not contain injection characters.
 */
export declare function validate(purl: PurlObject, throws: boolean): boolean;
export {};