import { Observable } from 'rxjs';
import { Service } from './metadata';
import { MessageEnvelope } from '@scion/workbench-application-platform.api';
/**
 * Message bus to communicate with workbench application platform.
 */
export declare abstract class MessageBus implements Service {
    /**
     * Allows to receive messages sent by application platform.
     */
    abstract get receive$(): Observable<MessageEnvelope>;
    /**
     * Initiates a request and receives replies continuously.
     *
     * Provide options object to control the subscription.
     */
    abstract requestReceive$(envelope: MessageEnvelope, options?: {
        once: boolean;
    }): Observable<MessageEnvelope>;
    /**
     * Posts a message to the application platform.
     */
    abstract postMessage(envelope: MessageEnvelope): void;
    /**
     * Initiates a request-reply communication with the application platform.
     */
    abstract requestReply(envelope: MessageEnvelope): Promise<MessageEnvelope>;
    /**
     * Lifecycle hook that is called when this service is destroyed.
     */
    abstract onDestroy(): void;
}
/**
 * Default implementation of {MessageBus}.
 *
 * Communication is based on `postMessage` and `onmessage` to safely communicate cross-origin with the window parent.
 */
export declare class DefaultMessageBus implements MessageBus {
    private _destroy$;
    private _ancestorOrigin;
    private _stream$;
    constructor();
    installHostMessageListener(): void;
    get receive$(): Observable<MessageEnvelope>;
    postMessage(envelope: MessageEnvelope): void;
    requestReceive$(envelope: MessageEnvelope, options?: {
        once: boolean;
    }): Observable<MessageEnvelope>;
    requestReply(envelope: MessageEnvelope): Promise<MessageEnvelope>;
    onDestroy(): void;
}
/**
 * Returns the ancestor origin, or `null` if not supported by the user agent.
 */
export declare function determineAncestorOrigin(): string;