/**
 * Minimal JSON-RPC 2.0 line transport over a paired stream. One newline-
 * terminated JSON frame per message; request correlation by numeric id.
 *
 * The gateway core is intentionally dependency-free: it must run in any
 * environment (smoke tests, dsh host, standalone) without touching the
 * published dsh package set. This transport mirrors the framing semantics of
 * the official `@deepseek-ai/dsh-sdk-protocol` line transport.
 *
 * @module dsh-subagent-codex-plus/gateway/transport
 */
import type { Readable, Writable } from 'node:stream';
/** Structured JSON-RPC error carried to callers of {@link JsonRpcLineTransport.request}. */
export declare class JsonRpcTransportError extends Error {
    readonly code: number;
    readonly data?: unknown | undefined;
    constructor(code: number, message: string, data?: unknown | undefined);
}
export type JsonRpcRequestHandler = (method: string, params: unknown) => unknown | Promise<unknown>;
export type JsonRpcNotificationHandler = (method: string, params: unknown) => void;
/**
 * Frame, dispatch, and correlate JSON-RPC messages on one input/output pair.
 * Starts reading on {@link start}; requests reject once closed.
 */
export declare class JsonRpcLineTransport {
    private readonly input;
    private readonly output;
    private readonly pending;
    private buffer;
    private sequence;
    private closed;
    private requestHandler;
    private notificationHandler;
    constructor(input: Readable, output: Writable);
    /** Register the handler for server-initiated requests. */
    onRequest(handler: JsonRpcRequestHandler): void;
    /** Register the handler for server-initiated notifications. */
    onNotification(handler: JsonRpcNotificationHandler): void;
    /** Begin consuming input frames. Idempotent. */
    start(): void;
    /**
     * Send one request and await its correlated response.
     * @param method - RPC method name.
     * @param params - positional or named parameters.
     * @param signal - optional abort for this request only.
     */
    request(method: string, params: object, signal?: AbortSignal): Promise<unknown>;
    /** Send one fire-and-forget notification. */
    notify(method: string, params?: object): void;
    /** Reject all outstanding requests and stop accepting new ones. Idempotent. */
    close(): void;
    private onData;
    private handleLine;
    private handleServerRequest;
    private write;
    private failAll;
}