import type { PdfRenderOptions } from '../types/PdfRenderOptions.js';
/**
 * Validates `pdfToPngConvertOptions.outputFolder` with the same sandbox-parity contract
 * applied to `diffsOutputFolder` and `allowedInputRoot`:
 *
 * - rejects non-string / empty / whitespace-only values
 * - rejects a path that already exists as a non-directory
 * - rejects a path whose existing chain contains any symbolic link (closes CWE-59 /
 *   CWE-61 redirect attacks where an attacker pre-plants a symlink so the renderer
 *   writes intermediate PNGs to a target outside the intended workspace)
 * - takes library ownership of leaf-directory creation for the resolved path AND the
 *   `actual/` / `expected/` namespaces that `renderPdfPages` writes into, then re-asserts
 *   each leaf is a real (non-symlink) directory. This closes the residual validate→render
 *   TOCTOU window that the path walker cannot cover on its own: once a non-symlink
 *   directory exists at every future write destination, an attacker can no longer plant a
 *   symlink there between validation and the renderer's first write (CWE-367 / CWE-61).
 *
 * Returns the resolved absolute path so downstream renderer calls operate on a stable
 * location, regardless of process cwd changes between configuration and render time.
 * Returns `undefined` when no `outputFolder` was supplied (in-memory render).
 */
export declare function validateRenderOutputFolder(outputFolder: PdfRenderOptions['outputFolder']): string | undefined;