/**
 * Copyright 2020 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { APICaller } from '../apiCaller';
import { GRPCCall, SimpleCallbackFunction, RequestType } from '../apitypes';
import { APICallback } from '../apitypes';
import { OngoingCall, OngoingCallPromise } from '../call';
import { CallOptions } from '../gax';
import { GoogleError } from '../googleError';
import { PageDescriptor } from './pageDescriptor';
export declare class PagedApiCaller implements APICaller {
    pageDescriptor: PageDescriptor;
    /**
     * Creates an API caller that returns a stream to performs page-streaming.
     *
     * @private
     * @constructor
     * @param {PageDescriptor} pageDescriptor - indicates the structure
     *   of page streaming to be performed.
     */
    constructor(pageDescriptor: PageDescriptor);
    /**
     * This function translates between regular gRPC calls (that accepts a request and returns a response,
     * and does not know anything about pages and page tokens) and the users' callback (that expects
     * to see resources from one page, a request to get the next page, and the raw response from the server).
     *
     * It generates a function that can be passed as a callback function to a gRPC call, will understand
     * pagination-specific fields in the response, and call the users' callback after having those fields
     * parsed.
     *
     * @param request Request object. It needs to be passed to all subsequent next page requests
     * (the main content of the request object stays unchanged, only the next page token changes)
     * @param callback The user's callback that expects the page content, next page request, and raw response.
     */
    private generateParseResponseCallback;
    /**
     * Adds a special ability to understand pagination-specific fields to the existing gRPC call.
     * The original gRPC call just calls callback(err, result).
     * The wrapped one will call callback(err, resources, nextPageRequest, rawResponse) instead.
     *
     * @param func gRPC call (normally, a service stub call). The gRPC call is expected to accept four parameters:
     * request, metadata, call options, and callback.
     */
    wrap(func: GRPCCall): GRPCCall;
    /**
     * Makes it possible to use both callback-based and promise-based calls.
     * Returns an OngoingCall or OngoingCallPromise object.
     * Regardless of which one is returned, it always has a `.callback` to call.
     *
     * @param settings Call settings. Can only be used to replace Promise with another promise implementation.
     * @param [callback] Callback to be called, if any.
     */
    init(callback?: APICallback): OngoingCall;
    /**
     * Implements auto-pagination logic.
     *
     * @param apiCall A function that performs gRPC request and calls its callback with a response or an error.
     * It's supposed to be a gRPC service stub function wrapped into several layers of wrappers that make it
     * accept just two parameters: (request, callback).
     * @param request A request object that came from the user.
     * @param settings Call settings. We are interested in `maxResults`, autoPaginate`, `pageToken`, and `pageSize`
     * (they are all optional).
     * @param ongoingCall An instance of OngoingCall or OngoingCallPromise that can be used for call cancellation,
     * and is used to return results to the user.
     */
    call(apiCall: SimpleCallbackFunction, request: RequestType, settings: CallOptions, ongoingCall: OngoingCall): void;
    fail(ongoingCall: OngoingCallPromise, err: GoogleError): void;
    result(ongoingCall: OngoingCallPromise): import("../call").CancellablePromise<import("../apitypes").ResultTuple>;
}