import childProcess from 'child_process';
import { Transform, Writable } from 'stream';
import _debug from 'debug';
import { System } from './system';
interface ChildProcessEnv {
    [key: string]: any;
}
interface ChildProcessOptions {
    env?: ChildProcessEnv;
    cwd?: string;
}
export declare function lines(chunk: unknown): Generator<string, void, undefined>;
export declare function createLineStream(): Transform;
export declare function createDebugStream(debug: ReturnType<typeof _debug>): Writable;
export declare function resolveChildExit(child: childProcess.ChildProcess): Promise<void>;
export declare function fork(sys: System, modulePath: string, args?: string[], { env, cwd, execArgv, }?: ChildProcessOptions & {
    execArgv?: string[];
}): childProcess.ChildProcess;
/**
 * For cross-OS compatibility, this method wraps the 3rd-party 'cross-spawn.sync()' method instead
 * of node's native child_process.spawnSync(). Essentially, all the workable options for using the
 * node's 'child_process' lib with Windows requires us to sanitize the inputs, which is tricky
 * because there are many edge cases. The 'cross-spawn' lib handles some args escaping and
 * processing for us.
 *
 * NOTE: This wraps the 'cross-spawn.sync()' method instead of the asynchronous
 * 'cross-spawn.spawn()' to simplify implementation - callers of this method should only care about
 * the results of the spawn execution after the child process has fully closed.
 *
 * CAUTION: This is potentially vulnerable to command injection attacks, especially on Windows OS
 * if it deals with user inputs in the 'args' parameter. Therefore, extra protection is required
 * if handling user inputs in the 'args' parameter (i.e. implement an allow-list, etc.).
 * Currently, we indirectly deal with user inputs in only one case - when handling the user's
 * block code directory name for transpilation in `block_builder.js` (i.e. the user could
 * potentially inject content into their directory path name, but this is difficult to do due to
 * reserved character restrictions in directory names for Windows).
 *
 * FAQ:
 * - Why doesn't using child_process.execFile() suffice, if it mitigates against bad args?
 *   Windows OS does NOT support executing child_process.execFile() on a single '.cmd' or '.bat'
 *   file. There are undocumented ways to use child_process.execFile() on Windows, but each option
 *   makes usage vulnerable to command injection:
 *   (1) Use child_process.execFile() for a single '.cmd|bat' file with the '{shell: true}' option.
 *       From the node docs: "If the shell option is enabled, do not pass unsanitized user input
 *       to this function."
 *       src: https://nodejs.org/dist/latest-v12.x/docs/api/child_process.html#child_process_spawning_bat_and_cmd_files_on_windows).
 *   (2) Use child_process.execFile() with the cmd.exe process itself, then pass in the '.cmd|bat'
 *       file as the args for execution. This spawns the actual Command Prompt process (which is
 *       essentially like passing in the '{shell: true}' option).
 * - Why not always use child_process.spawn()?
 *   Similar to the options above, for Windows compatibility we have to pass in the '{shell: true}'
 *   option when using child_process.spawn(), which puts us at risk against command injection.
 *
 * Also see:
 * - https://medium.com/@nodepractices/were-under-attack-23-node-js-security-best-practices-e33c146cb87d
 *   "Prefer using child_process.execFile which by definition will only execute a single command
 *   with a set of attributes and will not allow shell parameter expansion." The exception is
 *   Windows, as explained above.
 * - https://www.oreilly.com/library/view/securing-node-applications/9781491982426/ch01.html
 *   "Although execFile or spawn are safer alternatives to exec, these methods cannot completely
 *   prevent command injection... When writing the validation logic, use a whitelist approach..."
 */
export declare function dangerouslyCrossSpawn(sys: System, filePath: string, args: Array<string>, { env, cwd }?: ChildProcessOptions): childProcess.ChildProcessWithoutNullStreams;
export declare function dangerouslyCrossSpawnAndReturnTrimmedOutputAsync(sys: System, filePath: string, args: Array<string>, { env, cwd }?: ChildProcessOptions): Promise<string>;
export {};