/**
 * Environment check: is the system ssh present and what does it support
 *
 * The result is computed once per process: the client version doesn't
 * change on the fly, and spawning a process for every command would be wasteful.
 */
import { type RunnerConfig, type SshCapabilities } from './ssh-args.js';
/** Parsed OpenSSH version */
export interface SshVersion {
    major: number;
    minor: number;
    /** Original string, as printed by ssh -V */
    raw: string;
}
/** What the detected client supports */
export interface SshRuntime {
    /** Whether the binary was found */
    available: boolean;
    version?: SshVersion;
    /** Whether connection multiplexing is supported */
    multiplexing: boolean;
    /** Why multiplexing is unavailable */
    multiplexingDisabledReason?: string;
    /** Whether SSH_ASKPASS_REQUIRE=force is supported — without it a password can't be supplied */
    askpassForce: boolean;
    /**
     * Whether file transfers run over SFTP rather than the classic scp protocol.
     * This determines the fate of the remote path: in the classic protocol
     * it's parsed by the server's shell, in SFTP mode the destination path is
     * taken literally.
     */
    scpOverSftp: boolean;
    /** Directory for control sockets and the askpass script */
    controlDir: string;
}
/**
 * Parse the output of `ssh -V`
 *
 * Examples: "OpenSSH_10.2p1, LibreSSL 3.3.6",
 *           "OpenSSH_8.9p1 Ubuntu-3ubuntu0.4, OpenSSL 3.0.2",
 *           "OpenSSH_for_Windows_8.6p1, LibreSSL 3.4.3"
 */
export declare function parseSshVersion(output: string): SshVersion | undefined;
/**
 * Compute capabilities from version and platform — a pure function
 */
export declare function computeRuntime(input: {
    platform: NodeJS.Platform;
    version?: SshVersion;
    controlDir: string;
}): SshRuntime;
/**
 * Directory for control sockets.
 *
 * Not the system temp directory: a predictable name in a world-readable
 * location is an opportunity to plant a socket of one's own. 0700
 * permissions leave access to the owner only.
 */
export declare function resolveControlDir(env?: NodeJS.ProcessEnv): string;
/**
 * Detect the system ssh and its capabilities (result is cached)
 */
export declare function detectRuntime(options?: {
    force?: boolean;
}): Promise<SshRuntime>;
/** Reset the cache — used in tests */
export declare function resetRuntimeCache(): void;
/** Capabilities in the shape expected by argument building */
export declare function toCapabilities(runtime: SshRuntime): SshCapabilities;
/**
 * Check that the environment can handle this profile.
 *
 * @throws SSHUnsupportedConfigError if the profile needs secret input
 *         and the client can't do that
 */
export declare function assertProfileSupported(config: RunnerConfig, runtime: SshRuntime): void;